JP2002012543A - N,n'-disubstituted guanidine and its use as stimulant amino acid antagonist - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a treatment agent for neuropathy associated with the excessive stimulation of neurocytes. SOLUTION: This treatment agent comprises, as an active ingredient, an N,N'-disubstituted guanidine having high affinity for PCP receptor of neurocytes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION Cross-Reference of Related Applications This application is a subject of U.S. application Ser. No. 0, filed Jul. 10, 1986.
No. 6,884,150, corresponding to a continuation-in-part application of PCT / US87 / 01545 (and its US counterpart) dated June 26, 1987, which is a continuation-in-part application of US Pat. No. 6,884,150.

[0002] The present invention relates to N, N'-
The present invention relates to disubstituted guanidine analogs and compounds and pharmaceutical compositions containing them. Further, the present invention provides a method for treating N-methyl-d-
The present invention relates to a method for treating a nervous system disease including excessive excitation of nerve cells by an agonist of aspartate (NMDA) receptor. Due to its excessive agitation, dysfunction of the nervous system in the case of epilepsy and hypoxia, hypoglycemia, ischemia, trauma and neurodegenerative diseases such as Huntington's chorea, amyotrophic lateral sclerosis (ALS ), Neuronal degeneration can occur in the case of Alzheimer's disease and Down's syndrome.

[0003]

BACKGROUND OF THE INVENTION A wide variety of substituted guanidines are disclosed in the patent literature. (Example) No. 1411731 and No. 1422506,
Diphenylguanidine is disclosed as a rubber cure accelerator. No. 1597233 discloses that N is used as a rubber curing accelerator.
-O-tolyl-N'-phenyl-guanidine is disclosed. No. 1672431 discloses N, N′-di-o-methoxyphenylguanidine, which is particularly useful for therapeutic purposes in the form of a water-soluble salt. No. 173338,
Np-dimethyl-amino-phenyl-N'-phenylguanidine is disclosed as a rubber cure accelerator. First
No. 795738 is N-diethyl-N′-phenyl-guanidine, N-diethyl-N-isoamylguanidine,
N-dimethyl-N'-isoamylguanidine and N-
Disclosed is a method for preparing N, N'-dialkyl-di-substituted guanidines, including dimethyl-N'-ethylguanidine. No. 1,850,682 discloses a process for preparing a disubstituted guanidine rubber accelerator having an additional substituent on the imine nitrogen atom. No. 2,145,214 discloses the use of disubstituted guanidines, such as diarylguanidines, especially dixylylguanidine, as anthelmintics.
As insecticides and moth larvicides, No. 2254509 discloses symmetric-di-2-octyl-guanidine, and Nos. 2274476 and 2289542 disclose:
A symmetric-dicyclohexylguanidine is disclosed. No. 2,633,474 discloses 1,3-bis (o-ethylphenyl) guanidine and 1,3-bis (p
-Ethylphenyl) guanidine is disclosed. Thirty first
No. 17994 discloses N, N ', N "-trisubstituted guanidines and their salts as bacteriostatic compounds.
No. 3140231 discloses N-methyl- as an antihypertensive drug.
And N-ethyl-N'-octylguanidines and their salts. No. 3248246,
The substituent is a hydrophobic hydrocarbon group, one of which is 1,3-naphthylmethyl and the other is n-butyl.
A disubstituted guanidine is described (Example 5). No. 3,252,816 discloses various N-substituted and unsubstituted sinamyl-guanidines and the corresponding N′- and N ″ -alkyl-substituted compounds and their salts as antihypertensive agents. No. 1 describes N-2-adamanto-1-yl- and N- with at most two lower alkyl groups on the N'- and / or N "-nitrogen atoms as sympathicolytic and antiviral agents. Disclosed are 2-homoadamant-1-yl-oxy-ethyl-thioethyl- and aminoethylguanidine derivatives. No. 3,301,755 discloses N-ethylene unsubstituted alkyl-guanidines and the corresponding N'- and / or N "-lower alkyl compounds as hypoglycemic and antihypertensive agents.
No. 669 discloses N-cyclohexylamino- (3,3-dialkyl-substituted-propyl) -guanidines and the corresponding N'-alkyl- and / or N "as hypotensive agents.
-Alkyl-substituted compounds are disclosed. 35479
No. 51 discloses 1,3-dioxolan-4-yl-alkyl-substituted guanidines having antihypertensive activity, and n- as a possible substituent on other amino groups.
Disclosed are lower alkyls, including butyl. 3639
No. 477 discloses propoxyguanidine compounds as having anorectic properties. No. 3681459
No. 3767927, No. 3803324, No. 39
No. 08013, 3976787 and 40149
No. 34 discloses aromatic substituted guanidine derivatives wherein the phenyl ring may contain hydroxy and / or halogen substituents for use in vasoconstriction treatment. Thirty-eighth
No. 04898 discloses N-benzylcyclobutenyl and N-benzylcyclobutenyl-alkyl-guanidines as blood pressure lowering agents and the corresponding N-alkyl and / or N "-alkyl-substituted compounds.
No. 8243 describes N as useful in the treatment of cardiac arrhythmias.
-Aralkyl-substituted guanidines and the corresponding N'-alkyl-n "alkyl and N ', N'-aralkyl compounds. No. 3,795,533 discloses o-halo as an antidepressant for overcoming mental depression. -Discloses benzylidene-aminoguanidines and their uses.
No. 4007181 discloses various N, N′-disubstituted guanidines having an arrhythmia and diuretic activity in which the imine nitrogen atom is replaced by adamantyl. No. 4051256 discloses N-phenyl- and N-pyridyl-N′-cycloalkyl- as antiviral agents.
Guanidines are disclosed. Nos. 4052455 and 4130663 disclose styrylamidines as analgesics or for the prevention of platelet aggregation. No. 41
No. 09014 discloses N-hydroxy substituted guanidines and the corresponding N-methyl disubstituted guanidines as vasoconstrictors. No. 4,169,154 discloses the use of guanidines in the treatment of depression. No. 4,393,007 discloses N-substituted and unsubstituted, N-substituted methyl-N'-unsubstituted, mono- and disubstituted-N "-unsubstituted and substituted guanidines as ganglionic blocking agents. No. 4,471,137 discloses N, N, N ', N "-tetraalkylguanidines as useful sterically hindered bases in chemical synthesis. No. 4709
No. 094 is a sigma brain receptor ligand.
Disclosed are 1,3-disubstituted-guanidines such as 1,3-dibutyl-guanidine and 1,3-di-o-tolyl-guanidine. For examples of other substituted guanidines, for example, No. 1422506, No. 1642180,
No. 1756315, No. 3159676, No. 3228
No. 975, No. 3248426, No. 3283003,
No. 3,320,229, No. 3,479,437, No. 3,547
No. 951, No. 3639477, No. 3784643,
No. 3949089, No. 3975533, No. 4060
See 640 and 4161541. Geluk et al., "Journal of Medicinal Chemistry"
(J. Med. Chem.), 12712 (1969) describe various adamantyl disubstituted guanidines as possible antiviral agents, such as N, N'-di- (adamantan-1-yl).
-Guanidine hydrochloride, N- (adamantan-1-yl-
It describes the synthesis of N'-cyclohexyl-guanidine hydrochloride and N- (adamantan-1-yl) -N'-benzyl-guanidine hydrochloride.

According to the present invention, it has been found that certain N, N'-disubstituted guanidines have high PCP receptor binding activity.

[0005] The amino acid L-glutamate is widely believed to act as a chemical messenger at excitatory synapses in the central nervous system. The neuronal response to glutamate is complex, with at least three different receptor types: KA, QA and NMDA
It is likely that subtypes, each of which are named for their relatively specific ligands, namely kainate, quisqualate and N-methyl-D-aspartate, respectively. These receptors
Amino acids that activate one or more of the types
It is called excitatory amino acid (EAA).

[0006] The NMDA subtype of excitatory amino acid receptor is activated during normal excitatory synaptic transmission in the brain. Activation of NMDA receptors under normal conditions is a phenomenon of long-term synergy at excitatory synapses,
Involved in memory-like phenomena. Excessive neuronal excitation occurs during epileptic seizures and overactivation of NMDA receptors has been shown to contribute to the pathophysiology of epilepsy.

[0007] NMDA receptors also develop after cerebral ischemia
It is strongly involved in the death of living neurons. Ischemic brain attack,
Endogenous glutamer, eg after a stroke or heart attack
Over-release of the NMDA receptor
Overstimulation occurs. In connection with NMDA receptor
That is the ion channel. Recognition site, sand
That is, the NMDA receptor is located outside the ion channel.
It is. Glutamate interacts with NMDA receptor
Then, by opening the ion channel,
The flow of cations through the cell membrane, such as C
a²⁺And Na ⁺And K from cells⁺Flow
Become. Interaction between glutamate and NMDA receptor
The flow of this ion, especially Ca²⁺Ionic
Flow can play an important role in neuronal cell death
Is believed. For example, Rosman and Olney,
Lenses in Neuroscience
ci.), 10 (7), 299-302 (1987).

[0008] Thus, agents that block the response to NMDA receptor activation are caused by the treatment of neurological disorders, such as epilepsy, and hypoxia or hypoglycemia, or the brain that develops during stroke, trauma and heart attacks. It has therapeutic use in preventing neuronal cell death after ischemia. Some nervous system disorders involve neurodegeneration that can be due to over-activation of the NMDA receptor. Therefore, NMDA
Antagonists of the receptor-mediated response hold promise for the treatment of diseases such as Alzheimer's disease, Huntington's chorea, amyotrophic lateral sclerosis and Down's syndrome.

[0009] Studies of the NMDA receptor-ion channel complex have led to the determination of the receptor site within the ion channel known as the PCP receptor. Vincent, Kartarobsky, Geneste, Kamenka and Razdunsky, Proceedings of the National Academy of Sciences of the USA
c. Natl. Acad. Sci. USA), 76, 4678-46
82 (1979), Zookin, S. R. and Zookin, R.S., "Proceedings of the
National Academy of Sciences of the USA "(Proc. Natl. Acad. Sci. U.
SA), 5372-5376 (1979), Sonders,
Keana and Webber, "Trends in Neurosci.", 11 (1), 37-4.
0 (1988) and Anise, Berry, Burton and Lodge, "British Journal of Pharmacology" (Br. J. Pharmacol.), 79, 565-5.
75 (1983). Compounds that bind to the PCP receptor can interrupt the flow of ions through cell membranes by acting as ion channel blocks.
In this way, an agent that interacts with the PCP receptor
Acts as a non-competitive blocker that reduces the agonism of glutamate at the NMDA receptor.

[0010] Known PCP receptor ligands include P
CP [synthetic heroin], ie phencyclidine, analogs such as 1- [1- (2-thienyl) -cyclohexyl] -piperidine (TCP), benzomorphan (Sigma)
Opiates, dioxiranes and 5-methyl-10,1
There is 1-dihydro-5H-dibenzo [A, D] cycloheptane-5,10-imine (i.e., drug MK-801, see U.S. Patent No. 4,399,141). Also, Wong, Kemp, Priestley, Knight, Woodwolf and Ibersen, "Proceedings of the National Academy of Sciences of the USA" (Proc. Natl. Acad. Sc.)
i. USA), 83, 7104-7108 (1986). MK-801 is clearly the most potent selective PCP receptor ligand / NMD known to date
A channel blocker.

We have identified compounds that exhibit high activity for binding to the PCP receptor and are structurally different from known PCP ligands.

[0012]

SUMMARY OF THE INVENTION The object of the present invention is to
The object is to provide N, N'-disubstituted guanidines that exhibit a high affinity for the PCP receptor with respect to the MDA receptor-channel complex.

[0013] Another object of the present invention is to provide N, N'-disubstituted guanidines to facilitate PCP receptor research.

Still another object of the present invention is to provide a nerve condition,
For example, to provide N, N'-disubstituted guanidines useful for treating nervous system diseases associated with epilepsy and neurodegeneration.

Still another object of the present invention is to provide a method for treating a nervous system disease associated with excessive excitation of nerve cells by an agonist of NMDA receptor.

It is a further object of the present invention to relate to excessive excitation of neurons by agonists of the NMDA receptor by administering an effective amount of an N, N'-guanidine compound having a high affinity for the PCP receptor. For example, treating nervous system dysfunction that induces epilepsy.

Yet another object of the present invention is to administer an effective amount of an N, N'-disubstituted guanidine compound having a high affinity for the PCP receptor to provide hypoxia, ischemia, hypoglycemia, brain and To treat a neurodegenerative condition and / or neuronal death, such as due to spinal cord injury.

Yet another object of the present invention is to provide various neurodegenerative diseases such as Huntington's chorea, muscle by administering an effective amount of an N, N'-disubstituted guanidine compound having a high affinity for the PCP receptor. To treat neurodegenerative conditions associated with amyotrophic lateral sclerosis, Alzheimer's disease and Down's syndrome.

If you are familiar with the art, this specification
By further reading (including the claims)
Still other objects and advantages of the present invention will become apparent.

BRIEF DESCRIPTION OF THE FIGURES The invention, when considered in conjunction with the accompanying drawings, will be better understood, and the evaluation of various other objects, features and attendant advantages of the invention will be more complete. Should be. FIG. 1 is a graph showing data obtained from the in vitro neurotoxicity assay described below. Normalize cell viability as a percentage of the highest cell number,
The results are plotted against glutamate concentration.

[0021]

SUMMARY OF THE INVENTION The foregoing objects have been achieved by the determination of certain N, N'-disubstituted guanidines that exhibit high binding affinity for the PCP receptor site.

[0022]

DETAILED DESCRIPTION OF THE INVENTION Preferred N, N'-disubstituted guanidines of the present invention have the formula

Embedded image Wherein R and R ′ are each an alkyl group having at least 4 carbon atoms or a carbocyclic aryl group having at least 6 carbon atoms, for example, R and R ′ can be the same or different; Alkyl having 4 or more carbon atoms, for example 4 to 12 carbon atoms, preferably a linear alkyl group, more preferably 4 to 4 carbon atoms.
Alkyl groups having 8 carbon atoms such as butyl, isobutyl, t-butyl, amyl, hexyl, octyl,
Nonyl and decyl, cycloalkyl having 3 to 12 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl, 1,4-methylene-cyclohexane, adamantyl, cyclopentylmethyl, cyclohexylmethyl, 1- or 2-cyclohexylethyl And 1-, 2- or 3-cyclohexylpropyl, for example having up to 18 carbon atoms,
Carbocyclic aryl, alkaryl or aralkyl containing 1-3 independent or fused aromatic rings, for example phenyl,
Benzyl, 1- and 2-phenylethyl, 1-, 2-
Or 3-phenylpropyl, o-, m- or p-
Tolyl, m, m'-dimethylphenyl, o-, m- or p
-Ethylphenyl, m, m'-diethylphenyl, m-methyl-m'-ethylphenyl and o-, m- or p-propylphenyl, naphthyl, 2-naphthyl and biphenyl, and aromatic heterocycles such as pyridyl, Pyrazinyl, pyrimidyl, furyl, pyrrolyl, thienyl, thiazolyl, oxazolyl, imidazolyl, indolyl and benzothiazolyl).

Further, R and R 'hydrocarbon groups include
2, 3, 3 or more substituents, for example 1-8
Alkyl having two carbon atoms, such as methyl, ethyl, halo, such as chloro, bromo, iodo, fluoro,
Nitro, azido, cyano, isocyanate, amino, lower alkylamino, di-lower alkylamino, trifluoromethyl, alkoxy having 1-8 carbon atoms,
For example, methoxy, ethoxy and propoxy, acyloxy, for example alkanoyloxy having 1-8 carbon atoms, for example acetoxy and benzoxy, amide,
For example, acetamido, N-ethylacetamido, carbamide such as carbamyl, N-methylcarbamyl, N,
N'-dimethylcarbamyl and the like may be present.

Particularly preferred are compounds of the formula (I) wherein R
And R ′ each represent, for example, one of the aforementioned substituents at the o-, m- or p-position or at the o-, p- or m, m′-position (when the phenyl group is disubstituted) or Is a phenyl group, which need not necessarily be the same, or R is as defined above and R 'is adamantyl.

Preferred compounds include N, N'-di-m-tolyl-guanidine (DMTG), N, N'-di-o-iodo-phenyl-guanidine (DOIPG), N, N'-di-o.
-Ethylphenyl-guanidine (DOEPG) and N,
N'-di-m-ethylphenyl-guanidine (DMEPG)
There is.

The compounds listed above are disubstituted guanidines, a compound of this type which is disclosed in US Pat.
No. 709094 (the disclosure of which is incorporated herein by reference). Preferred among the compounds described therein are compounds of the formula

Embedded image Wherein R and R ¹ are each independently an alkyl, cycloalkyl, carbocyclic aryl, alkaryl or aralkyl. As one class, the patent describes these compounds as exhibiting high selective binding activity to sigma brain receptors. DTG itself also exhibits strong selectivity for sigma receptors [Webber, Sonders, Calm, McLean, Pou and Keana, "Proceedings of the National Academy of Sciences of the You". S.A. "(Proc. Na
tl. Acad. Sci. USA) 83, 8786-8788 (1
986)]. However, it has been determined that certain members of this class of disubstituted guanidine also exhibit high binding activity for the PCP receptor.

These N, N'-disubstituted guanidines can be readily prepared by conventional chemical reactions, for example, when R and R 'are the same, reaction of the corresponding amine with cyanogen bromide. Other methods that can be used include the reaction of an amine with a preformed alkyl or aryl cyanamide. Safer et al., "Journal of Organic Chemistry" (J. Org. Chem.), 13: 924 (194).
See 8). This is a particularly good method for preparing N, N'-disubstituted guanidines whose substituents are not identical. For a new synthesis of asymmetric guanidines, see Durant et al.
"Journal of Medicinal Chemistry" (J.
Med. Chem.), 28: 1414 (1985) and Marianov et al., "Journal of Organic Chemistry" (J. Org. Chem.), 51: 1882 (1986). Do).

In a composition aspect, the invention is a pharmaceutical composition in unit dosage form suitable for systemic administration to a subject, eg, a human, which is effective to modify brain NMDA receptor mediated activity per unit dose. A large amount of N, N'-disubstituted guanidine, which is
The present invention relates to a pharmaceutical composition having a high affinity for a receptor.

In another composition embodiment, the present invention provides a composition comprising N,
N'-di-m-tolyl-guanidine, N, N'-di-o-iodo-phenyl-guanidine, N, N'-di-o-ethylphenyl-guanidine and N, N'-di-m-ethyl The present invention relates to a neuroprotective N, N'-disubstituted guanidine exhibiting high binding activity with respect to the PCP receptor in mammalian nerve cells, selected from the group consisting of phenyl-guanidine and physiologically acceptable salts thereof.

In a method aspect, the invention is directed to a method of treating or preventing a neurodegenerative disease, epilepsy or memory disorder, comprising administering to a subject in need of treatment an N, N'-disubstitution having a high affinity for the PCP receptor. A method comprising administering an effective amount of guanidine. Those N, N'-disubstituted guanidines have utility as non-competitive blockers of NMDA-receptor-mediated actions.

In yet another method embodiment, the present invention provides
A method of ameliorating the neurotoxic effects induced by glutamate that interacts with the NMDA receptor of a neuron, comprising administering to a subject, such as a human, who exhibits or is susceptible to the neurotoxic effect, the NMDA receptor.
The present invention relates to a method comprising administering an N, N'-disubstituted guanidine having a high affinity for the PCP receptor of a neuronal cell in an amount effective to block the ion channel of the ion channel complex. The term "high affinity" means that the compound exhibits an equilibrium dissociation constant of about 1 micromolar or less in a PCP receptor binding assay, typically the PCP receptor assay described below.

In another method embodiment, the invention comprises administering to a mammal an N, N'-disubstituted guanidine having a high affinity for the PCP receptor of a neuronal cell in an amount effective to inhibit neurotoxicity. , NMDA receptor-
The present invention relates to a method for inhibiting ion channel-related neurotoxicity.

The N, N'-disubstituted guanidines and other non-competitive blockers of the NMDA receptor agonists (a) increase the binding affinity for the PCP receptor by competitive substitution of tritiated TCP or MK-801. Measuring (b) measuring the current through the channel to assess the ability of the compound to block the passage of ions by the ion channel; (c) in an in vitro cytotoxicity test,
The ability of a compound to prevent neuronal cell death induced by exposure to glutamate can be measured and measured by methods that include (d) measuring in vivo neuroprotection using animal models.

The evaluation of the binding activity of the organic compound for the PCP receptor is performed using a radioligand binding assay. Compounds are tested by measuring their ability to replace tritiated TCP and tritiated MK-801 used for labeling PCP receptors. Evaluating the competitive displacement binding data, preferred compounds are those that exhibit high affinity (ie, low IC ₅₀ values) for the PCP receptor.

Under the binding activity test, at most about 1000
Nanomolar, preferably at most about 500 nanomolar IC
_A value of ₅₀ indicates a high binding affinity.

In electrophysiological studies, blocking the ion channels of the NMDA receptor channel complex allows Ca ²⁺ and Na to enter neurons.
⁺ Assess the ability of the compound to block the flow of ions. First, an ion channel is opened by activating the NMDA receptor. By measuring the passage of current, the flow of ions is measured. A decrease in current indicates blockage of the ion channel by ligand binding at the PCP receptor site.

Interference with ion channels is a dose dependent activity. In other words, as more NMDA receptor-channel complexes are activated by glutamate, blocking of the channel by non-competitive blockers becomes more effective.

In a neurotoxicity test, cultured mammalian neurons or cell lines expressing the EAA receptor were isolated from
In vitro exposure to glutamate and test compound.
The cell survival percentage indicates the ability of the compound to protect against glutamate-induced neuronal death. This in vitro cell death assay is described in further detail below.

In an in vivo neurotoxicity test, an experimental model such as McDonald's et al. [“Sigma and Phencylidine-Like Compounds as Molecular Probes in Biology” (Sigma and Phencylidine)
−like Compounds as Molecular Probes in Biology)
Pp. 697-707, eds.
88), NPP Books, Ann Arbor, Michigan]. In this model, N to the cerebral hemisphere
MDA injection induces lesions similar to those caused by hypoxia-ischemia. The ability of compounds to limit NMDA-induced lesions is a measure of their neuroprotective properties, and because the compound is administered intraperitoneally, the model also provides information about the ability of the compound to cross the blood-brain barrier.

Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. Accordingly, the preferred embodiments are described below, but are by way of example only and are not intended to limit the remainder of the specification in any way.

The entire text of all applications, patents and publications (if any) cited above are incorporated herein by reference.

[0042]

EXAMPLES In Production Examples 1 and 2, the melting points were measured in an open capillary tube with a Thomas-Hoover apparatus and are uncorrected. Analytical measurements for all of the compounds below are made by Desert Analytics (Tucson, Arizona) and are + 0.4% of theoretical for the given element. The NMR spectrum is CD _{3 on} General Electric QE-300.
Measured in OD, chemical shifts were determined in deuterated solvents (HCD ₂
(OD, 3.30). The IR spectrum is Nicolet 5DXB FT-IR
Was measured in KBr. All amines were purified by standard methods or used without direct purification where indicated. Cyanogen bromide was from Aldrich and stored with CaH ₂ molecular sieve 4A. Et ₂ O was distilled from benzophenone ketyl in the usual manner. All other solvents are reagent grade.

1. Preparation of N, N'-di-o-iodophenyl-guanidine (DOIPG) Cyanogen bromide solution (4.40 g, 38.2 mmol) and water
2-Iodoaniline (4.14 g, 18.9 mmol) in (70 ml) was heated at 70-80 ° C for 5 hours. The reaction mixture was decanted to separate an off-white solid (1.90 g), which was discarded and the supernatant was heated at the same temperature for another 16 hours.
The solution was cooled to 25 ° C. and precipitated from the solution as hydrobromide.
The OIPG is centrifuged and dried (500 mg, 10%).
The white powder thus formed is dissolved in boiling H ₂ O (20 ml) and to the clear solution is added 5N NaOH (2 ml). The resulting white precipitate was washed with water (3 × 4 ml), 95
%, Recrystallized from EtOH to obtain long white needle-like crystals DO
Obtain IPG (119 mg, 39% from hydrobromide): mp
161-162 ° C. Further recrystallization is repeated to obtain a sample for analysis: mp 161-162 ° C. Elementary analysis: Calculated _{(C 13 H 11 N 3 I} 2): C; 33.72, H; 2.
39, N; 9.07 Found: C; 33.80, H; 2.26, N; 8.78 ¹ H NMR: 7.506 (d, J = 7.8 Hz, 2H), 7.30
4 (t, J = 7.8 Hz, 2 H), 7.506 (d, J = 7.8 Hz,
2H), 7.817 (d, J = 7.8 Hz, 2H) IR: 729, 753, 1456, 1502, 157
2, 1613, 1647, 3056, 3387 cm ^-1

2. N, N'-di-m-tolyl-guanidine
Preparation of (DMTG) Cyanogen bromide (788 mg, 7.44 mmol) is placed in a 25 ml round bottom flask and m-toluidine (1.89 g, 17.6 mmol) is added dropwise. After the exothermic reaction had subsided, the residue was added to CH ₂ Cl ₂ (20 ml) and 5% HCl was added.
(5 × 10 ml). The pH of the aqueous extract is adjusted to 10 using 6N NaOH. Filtered off and the resulting precipitate (674mg, 38%), and recrystallized from _{EtOH / H 2 O, DMTG (} 240mg, 14%), white needles: Mp105-106 get ° C.. Elementary analysis: Calculated _{(C 15 H 17 N 3)} : C; 75.28, H; 7.1
6, N; 17.56 measurements: C; 75.42, H; 7.11 , N; 17.43 1 H NMR: δ2.289 (s, 6H), 6.814 (d, 2
H, J = 7.5 Hz), 6.939 (d, 2H, J = 7.5 Hz),
6.981 (s, 2H), 7.141 (t, 2H, J = 7.5 Hz) Kazarinova et al., Journal Analiceskoy Himii
(Zh.Anal.Khim.) 28: 1853 (1973)
And Chemical Abstracts (Chemical Abstracts)
s) 80: 97021 (1973).

Other suitable N, N'-disubstituted guanidines can be prepared in a similar manner.

Experimental procedure (Examples 3 and 4): Melting points were determined on a Thomas-Hoover apparatus and are uncorrected. NMR spectrum was measured by General Electric QE-300
The chemical shift was measured by a spectrometer, and the chemical shift was measured using a deuterated solvent (CHCl
₃ , expressed in ppm from the residual proton signal of δ7.265). IR spectrum is Nicolet FDXB FT
It was measured with an IR device. All solvents and reagents were reagent grade and used without purification. Microanalysis was performed at Desert Analytics in Tucson, Arizona.

3. N, N'-di -m- ethylphenyl - guanidine (DMEPG) manufacturing Et ₂ O (1 ml) Medium odor cyanide (650 mg, 6.14 mmol) of 3-ethylaniline (1.42 mg, 11.7 mmol ). After the exothermic reaction subsided, the viscous oil was heated at 150 ° C. for 15 minutes in a stream of N ₂ ,
Leave to cool to 25 ° C. The solid obtained is 95% EtOH
(20 ml) and 10% NaOH (20 ml) is added. A white precipitate formed which was filtered off and 50% EtOAc
The solution was recrystallized twice from an aqueous H solution to give N, N'-di-m-ethylphenyl-guanidine as white needles (620 mg, 20%).
To give: mp 96-98 ° C. Elementary analysis: Calculated _{(C 17 H 21 N 3)} : C; 76.37, H; 7.9
2, N; 15.72 Found: C; 75.93, H; 7.90, N; 15.76 ¹ H NMR (CDCl ₃ ): δ 1.216 (t, J = 7.5 H)
z, 6H), 2.608 (q, J = 7.5 Hz, 4H), 6.937
(m.6H), 7.222 (t, J = 7.8Hz, 2H) IR (CDCl 3): 2971,1629,1589,14
90, 1417, 1217 cm ^-1

4. Preparation of N, N'-di-o-ethylphenyl-guanidine (DOEPG) Cyanogen bromide solution (1.41 g, 1%) in 95% EtOH (3 ml)
(3.3 mmol) is added to an ice-cold solution of 2-ethylaniline (3.08 g, 25.4 mmol) in 95% EtOH (10 ml). The reaction mixture _{N 2} rapid stream for 30 minutes 150
Heat at ° C. The solid obtained is 95% EtOH (15 l)
And 10% NaOH (30 ml) is added. White needle-like crystals formed, which were collected by filtration and recrystallized twice from a 25% aqueous solution of EtOH to give white needle-like crystals of N, N'-di-o-ethylphenyl-guanidine (2.00 g, 59% Get): m
p158-161 ° C (Reference ¹ : 161.5-162 ° C). ¹ H NMR (CDCl ₃ ): δ 1.209 (t, J = 7.5H
z, 6H), 2.653 (q, J = 7.5 Hz, 4H), 7.054
-7.255 (m, 8H) IR ( CDCl 3): 2971,1629,1589,14
90, 1417, 1217 cm- ¹ Document ¹ : U.S. Pat. No. 2,633,474 (CA
47: 6171f), British Patent No. 716301 8399
82 (CA 49: 2112c), UK Patent 83998.
No. 2 (CA 55: 2166e)

5. Radioligand binding assay PCP receptor binding assays were performed using guinea pig or rat brain membranes as the receptor source. PC
The radioligand used for labeling the P receptor was (+) [ ³
H] is an MK-801 [97Ci / mmol] and ^[3 H] TCP (55Ci / mmol, Massachusetts, Cambridge, New England Nuclear, Inc.).

The (+) [ ³ H] MK-801 synthesis and PCP receptor binding assay protocols are described in Keina, Schertz, Qualum, Sonders and Weber,
It is reported in Life Science (Life Sci.) (1988, submitted). Briefly, in the protocol, guinea pig brain membrane final protein concentration is adjusted to 3 mg / ml and stored at -70 ° C. Rat brain membranes are labeled "detergent-treated membranes".
membranes)] [Mafi, Schneider, Boehm,
Lehman and Williams, Journal of Pharmacology and Experimental Therapeutics (J. Pharmacol. Exp. Ther.) 240
778-784 (1987)] and stored at -70 ° C at a protein concentration of 10 mg / ml. Receptor number or (+) [ ³ H] MK-801
Or with respect to affinity for ^{[3 H] 1- [1- (} 2- thienyl) cyclohexyl] Hiperijin ^([3 H] TCP), film storage (1 month) Effect of at -70 ° C. was observed.

For radioreceptor binding assays using guinea pig membranes, aliquots were thawed and 5 mM Tris HCl was added.
Alternatively, the cells were diluted with Tris acetate buffer (pH = 7.4) to the target concentration. Assays were performed with 0.8 ml membrane, 0.1 ml radiotracer and 0.1 ml buffer or unlabeled drug. For assays using rat membranes, thawed membranes were incubated at 32 ° C. at 1 mg / ml with 0.01% Triton X-1.
Incubated with 00 for 15 minutes, centrifuged three times to reduce the endogenous amino acid concentration, and finally reseated in assay buffer. Glycine and 1-glutamate were added to a final concentration of 1 μM each to give (+) [ ³ H] MK-801.
Alternatively, [ ³ H] TCP binding stimulation was maximized. Testing was performed with 400 μl membrane, 50 μl radioligand and 50 μl buffer or unlabeled drug.

In the case of (+) [ ³ H] MK-801 bond, 1
nM radioligand was incubated with 120 μg / ml guinea pig brain membrane protein or 200 μg / ml rat brain membrane for 4 hours at room temperature. 2 n for [ ³ H] TCP binding
M radioligand was incubated with 800 μg / ml guinea pig brain membrane or 300 μg / ml rat brain membrane for 45 minutes at room temperature. All assays were stopped by rapid vacuum filtration through Whatman GF / B glass fiber filters using a Brandel 48-well cell harvester (Brandel, Gethersburg, MD). The filter is 0. 0 when [ ³ H] TCP is used.
It was pre-soaked in 05% polyethyleneimine. The filters were washed three times with 5 ml of cold 5 mM Tris HCl (pH = 7.4). Each filter was dissolved in 10 ml of Cytoscint (ICN Biomedicals, Costa Mesa, Calif.) And radioactivity was measured by liquid scintillation spectrometry at a counting efficiency of 50%.

Non-specific binding was determined by (+) [ ³ H] MK-801.
For binding 10 μMPCP or (+) MK-801, [
³ H] TCP binding was defined as remaining in the presence of 100 μMPCP. Using the rat brain membrane prepared as described above, [ ³ H] CPP (3- (3) -N-methyl-D-aspartate-type glutamate receptor was used.
((±) 2-carboxypiperazin-4-yl) propyl-
1-phosphonic acid) [Murphy, Schneider,
Boehm, Lehmann and Williams, Journal of Pharmacology and Experimental
Therapeutics (J. Pharmacol. Exp.
r. ) 240, pp 778-784 (1987)], high affinity binding of ^[3 H] kainate for kainate glutamate receptors [Honor, de leisure and Nielsen, Neuroscience Letters (Neuroscience L
ett. ) Volume 65, pages 47-52 (1986)], and ^[3 H for quisqualate glutamate receptor] A
Binding of MPA (DL-α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid) [Murphy, Snowhill and Williams, Neurochem. Res. 12, Vol. 775-7.
82 (1987)].

The saturation data was obtained from EBDA [McPherson, Computer Programs Biomedicine.
(Computed. Program Biomed.) Vol. 17, 107-11.
4 (1983)] and LIGAND [Manson and Rhodebird, Analytical Biochemistry]
(Anal. Biochem.) 107: 220-239 (198).
0)] was evaluated by Scatchard analysis using both data analysis programs. IC ₅₀ values were determined by plotting and interpolating displacement curves on semi-log graph paper.

In a radioligand binding assay using a selective [ ³ H] -labeled ligand, DM was determined for binding to PCP receptors on guinea pig and rat brain membranes.
TG, DOIPG, DMEPG, DOEPG and DT
G was tested. (+) [ ³ H] MK-801 and [ ³ H] TCP were used for labeling PCP receptors. As is clear from Tables 1 and 2, guinea pigs (Table 1)
And DMTG, DOIPG, DOEPG and DMEPG show submicromolar affinities for PCP, as judged by their ability to displace two selective PCP receptor ligands for binding to brain membranes obtained from rat and rat (Table 2). Was. (The values in parentheses in Tables 1 and 2 indicate the number of experiments.) The parent compound DTG (Comparative Example)
It showed low affinity for the P receptor. That is,
PCP receptors are tolerant of a wide range of structural changes on compounds that bind to a site.

On the contrary, [ ³ H] CPP, [ ³ H] kainate and [ ³ H] CPP were used as specific radioligands, respectively.
^In assays using [3H] AMPA, none of the test compounds showed significant binding affinity for the N-methyl aspartate, kainate or quisqualate glutamate binding sites. DMTG and DOIPG did not cause more than 50% inhibition at 100 μM in these binding assays, implying that their neuroprotective effects were not due to direct blocking of the glutamate binding site.

[0057]

[Table 1]

[0058]

[Table 2]

6. Electrophysiological Assay Compounds were tested for their ability to achieve a dose-dependent inhibition of the NMDA-induced (+ glycine) response in rat hippocampal neurons maintained in cell culture. DOIPG and DMT
G was tested and each gave results very similar to the dose-dependent inhibitory effect exhibited by MK-801.

Hippocampal neurons were obtained from the CA1 region of the hippocampus of neonatal 1-3 day old rats (Long-Evans). Tissue lumps (<1 mm ³ ) are converted to papain (20 units m
l- ¹ ; Worthington-Cooper) for 30 minutes. Tissues were grown in complete growth medium (Earle's MEM, 20 mM glucose, 50 units / ml penicillin / streptomycin, 5% heat-inactivated fetal calf serum containing 2.5 mg / ml bovine serum albumin and 2.5 mg / ml trypsin inhibitor (Sigma), C
ollaborative Research serum extender) and dissociated into a single cell suspension by baking with a baked Pasteur pipette. Cells were mounted on glass-coated pieces coated with collagen / poly-D-lysine. Cultures were replenished by replacing half of the medium every three days. During the first week after placement, arabinosylcytosine (5 × 1
The 0 ^-6 M) by adding 1-2 days, inhibited the growth of non-neuronal cells.

All electrophysiological experiments were performed using whole-cell or outside-out patch clamp recordings from neurons grown for 1-3 weeks [Ha
mill, OD, Marty, A., Neher, E., Sakman, B. and Sigw
orth, FJ, Pflugers Arch., 391, 85-100 (1981)]. Agonists and antagonists were applied to neurons in whole cell experiments with a pressurized pipette (Picosprizer; General Valve). An irrigation pipette was used to insert the tip of the patch pipette into the opening through which the test solution was continuously flowing to apply the drug to the outer removal patch. External solutions were NaCl 165, KCl unless otherwise noted.
5, CaCl ₂ , HEPES 5 (N-2-hydroxyethylpiperazine-N′-2-ethanesulfonic acid, pH adjusted with NaOH)
Glycine 0.001 (unit: mM). The internal solution was CsCl 160, EGTA 10 (ethylene glycol-bis- (β-aminoethyl ether) -N, N,
N ', N'-tetraacetic acid), HEPES 5 (pH 7.
(Adjusted to 4) (all units are mM). The membrane current is
Filtered at 2,000 Hz (single channel recording) or 200 Hz (whole cell experiment) (-3 dB; 8-pole Bessel), respectively
Collected numerically at 100us or 8ms intervals. The experiments were performed at room temperature (20-25 ° C). [Chemical reagent source: N-methyl-
D-aspartate, Cambridge Research Biochemical
s; salt for recording solution, Aldrich (Gold Label) or Alfa
(Puratronic). ^[3 H] Kainate and ^[3 H] CPP and ^[3 H]
AMPA was purchased from Dupont / NEN (Boston, MA). ]

One second application of 50 μM NMDA in the presence of 1 μM glycine resulted in an internal total cell current at a holding potential of −40 mV.
100-400 pA was given. Repeated application to the same cells (every 30 seconds) resulted in less than 5% change in current for at least 30 minutes. NMDA for MK-801 (0.5-10μM)
When applied from the same pressure pipette, the internal current became progressively smaller with a series of applications. Recovery from this blocking state required repeated application of NMDA alone and was accelerated by maintaining the membrane potential at a positive voltage. PCP
(40 μM) had a similar effect. The effects of both antagonists were voltage-dependent, with a negative holding potential increasing inhibition, but at very high positive potentials (+80 mV) little antagonism was observed.

Like MK-801, both DOPIG (3 and 30 μM) and DMTG (30 μM) blocked NMDA current in a dose- and voltage-dependent manner. Continuous application produced progressively smaller currents. DOIPG and DMTG
Was reversed only by continuous or repeated application of NMDA. This reversal was increased by holding the membrane at a positive potential.

Single channel currents generated by application of NMDA to an outer ablation patch derived from the membrane of cultured rat hippocampal neurons were blocked by DOIPG, similar to MK-801. Sustained treatment of patches for these compounds in the presence of NMDA resulted in a decrease in channel opening probability and average channel opening time. In the absence of an antagonist, NM
DA-generated channel openings occurred with the same probability for at least 20 minutes. As in whole cell recording, the probability of reduction of channel opening and mean opening time was reversed by the sustained presence of the agonist without the use of an antagonist, and recovery was improved by holding the membrane at a positive potential.

7. In vitro neurotoxin assay The method of Huettner and Baughman [Huettner, JE. and Baug
hman, RW, J. Neurosci., 6, 3044-3060 (1986)], dissociated rat hippocampus cultures were prepared. 1 to 3 day old rats anesthetized with chloral hydrate (Sprague
Except cortex from -Dawley), excised hippocampus, dissociation solution containing no chlorine ions supplemented with 1mM kynurenic acid and _{10mM MgSO 3 (Choi, DW,} J.Neurosci., 7,369~379 (198
7)). The hippocampus was washed in the dissociation solution, and 37% in a dissociation solution containing 10 units / ml papain (Worthington).
Incubated at 2 ° C for 2 x 20 minutes. After the enzyme treatment, the tissue was
3 with trypsin inhibitor (Sigma type II-O)
The cells were cultured three times at 7 ° C. for 5 minutes each.

Cells were dissociated by treatment in growth medium and placed in the center of a 35 mm Primaria (Falcon) dish as a 0.15 ml drop of cell suspension. This dish is Mecanex BB type (WPI, New
Haven, using CT), has been previously stamped with a label 26 × 26 grid with total area of about 0.64 cm ² coated with poly--D- lysine and laminin (Collaborative Reseach). The cell concentration was 2.5 to 4.0 × 10 ⁵ per dish. The growth medium was 5% fetal calf serum (CCL), 5% limited supplemented calf serum (HyClone), 50 mM glucose, 50 units / ml.
Eagles minimal essential medium (MEM, Earle's salts) supplemented with penicillin / streptomycin and MITO + serum extender (Collaborative Reseach). Cells were maintained at 37 ° C. in a humidified 4.5% CO ₂ atmosphere. Cells were allowed to adhere to the plate surface for 12-14 hours, 1.5 ml of growth medium was added to each dish, 1 ml was removed and replaced with 1 ml of fresh medium. This method removed most of the cell debris and unattached cells. The area of cell attachment and growth did not significantly exceed the central area treated. Culture 2
After ４4 days, non-neuronal cell division was blocked by exposure to 5 μm cytosine arabinoside for 2-3 days.

The cells were maintained in a medium similar to the growth medium but without fetal calf serum. The medium was changed weekly by replacing 2/3 volume with fresh medium. Glutamate present in this medium was only that contained in calf serum, and the final concentration was 12 μM.

Before treatment, the sister culture was observed under a phase contrast microscope to confirm that the cultures were of comparable concentration. Glutamate contact was performed at 32-34 ° C using Choi, DW, Maulicci-Gedde, M. and Viriegstei.
n, AR, HEPES-buffer similar to that reported in J. Neurosci., 7, 257-268 (1987), but with Tris-HCl replaced with 10 mM HEPES and buffered to pH 7.4 at 34 ° C. Performed in "control salt solution" (CSS). Cultures were washed twice with CSS and cultured for 5 minutes in CSS containing 1 μm glycine and the compound to be tested (controls contained only 1 μm glycine). The use of glycine has been shown to enhance the effects of glutamate at the NMDA site [Johson, JW. and Ascher,
P., Nature, 325, 529-530 (1987)], and preculture with the test agent enhances the neuroprotective effect (Finkbeiner,
SC, et al., Proc. Natl. Acad. Sci. USA, 85, 4071
~ 4074 (1988)). CSS containing 1 μM glycine + drug and a known concentration of glutamate (0-1000 μM) was added by three changes and the culture was incubated for 5 minutes. Cultures were CSS 4
Twice, then washed with medium solution and placed in incubator overnight. The next day, the culture was removed from the incubator, washed twice with CSS, and treated with 0.4% trypan blue (this dye is only taken up by dead cells) for 5 minutes. Cultures were washed three times and viable cells in the grid area were counted using a phase contrast microscope. Live cells expressed as% of the highest cell number,
The results were plotted as a function of glutamate concentration.
Cultures that were not contacted with glutamate generally yielded 4500-5500 viable cells in the grid area.

DOIPG, DMTG, DMEPG, DO
EPG, their parent compounds DTG and MK-8
01 was tested for neuroprotection in a range of glutamate concentrations. As shown in FIG.
mDOIPG, DMEPG, DOEPG or DMTG
Alternatively, 0.5 μm MK-801, when compared to control values,
At a glutamate concentration of 30 to 1000 μm, an increase in living cells was observed. The degree of neuroprotection conferred by these compounds was significant at P <0.05 for glutamate concentrations of 30 μm and above at the doses tested (ANOVA and 2-tailed t-test). In contrast, DTG did not give a significant neuroprotective response at a dose of 30 μm.

8. In Vivo Neurotoxicity Measurement The protocol was changed at one point with an intraperitoneal injection of the test compound 15 minutes after, but not before, the NMDA injection into the brain,
The experimental model of McDonald's et al. (Supra) was used. DOIPG, DMTG and DMEPG were tested in this assay and NMD at doses ranging from about 10-100 μM / kg body weight.
A injection was found to protect against lesions caused by A injection.

These observations on the in vitro and in vivo neuroprotective effects of DOIPG, DMTG, DMEPG and DOEPG are consistent with their affinity for the brain PCP binding site and the inhibition of NMDA movement described above.

The disubstituted guanidines of the present invention are PCP
It is not chemically related to known NMDA channel blockers that act through the receptor. As aforementioned,
Conventionally, PCP / ketamine type, benzomorphane opiate, benz [f] isoquinoline compound and MK-
Only 801 was known to interact with the PCP receptor [Zukin and Zukin, Trends in Neurosci.
(1988), Sonders, Keena and Webber, Trends in Neuroscience
rosci. Vol. 11, No. 37-40 (1988), Wong, Kemp, Priestley, Knight, Woodruff and Iversin, Proceedings of the National Academy USA (Proc. Natl. Aca).
d. ScL USA, 83, 7104-7108 (1986)].

[0073]

The compounds of the invention can be administered intranasally, orally or by injection, for example, intramuscularly, intraperitoneally or intravenously.
Can be administered. The optimal dose can be determined by standard methods. Because most, if not all, of the N, N'-disubstituted guanidines used in this invention are substantially water-insoluble, they are usually pharmaceutically acceptable with protonated forms, such as organic or inorganic acids. Salts, such as hydrochlorides,
It is administered in the form of sulfate, hemi-sulfate, phosphate, nitrate, acetate, oxalate, citrate and the like.

The compound of the present invention is prepared by using a conventional excipient,
That is, it can be used as a mixture with a pharmaceutically acceptable organic or inorganic carrier substance for parenteral, enteral or nasal administration that does not decompose by reacting with the active ingredient. Suitable pharmaceutical carriers include water, salt solutions, alcohols, vegetable oils, polyethylene glycols, gelatin, lactose, analogs, magnesium stearate, talc, silicic acid, viscous paraffin, aromatic oils, fatty acid monoglycerides and diglycerides, petroleum ether Examples include, but are not limited to, fatty acid esters, hydroxymethylcellulose, polyvinylpyrrolidone, and the like. The pharmaceutical preparations can be sterilized and, if desired, adjuvants, such as lubricants,
Preservatives, stabilizers, wetting agents, emulsifiers, salts for osmotic pressure adjustment,
Those which do not adversely react with the buffering agent, coloring agent, flavoring agent and / or fragrance substance and other active ingredients can be mixed.

For parenteral administration, particularly suitable are solutions, preferably oily or aqueous solutions and implants, including suspensions, emulsions, or suppositories. Ampules are a convenient unit dosage form.

For oral administration, particularly suitable are tablets, dragees or capsules and the like, which contain talc and / or carbohydrate carriers / binders, where the carriers are lactose and / or corn starch and / or potato starch. preferable. Syrups, elixirs and the like can also be used using a medium imparted with sweetness. The long-acting composition can be formulated by applying the active ingredient to a coating having a different disintegration property, for example, by microencapsulation or a multilayer coating.

Parenteral administration, eg, intraperitoneal, intramuscular, etc., is preferred, and the compounds of this invention may be used in the treatment (treatment) of mammals, eg, humans, wherein the pathology of the disease is associated with hyperexcitation of neurons by agonists of the NMDA receptor. ) Is particularly useful.
Typically, such subjects include Huntington's chorea, amyotrophic lateral sclerosis, Alzheimer's disease and neurodegenerative diseases such as Down's syndrome. It is also suitable for the treatment of a subject suffering from dysfunction of the nervous system, for example due to epilepsy, and degeneration of nerve cells resulting from hypoxia, ischemia, hypoglycemia or trauma. Typical candidates for treatment include patients with cardiac onset, stroke, brain and spinal cord injury.

The practically suitable amount of the active ingredient to be used depends on the particular compound used, the particular dosage form, the mode of administration and the site of administration. Optimal dosage rates for a given dosing protocol can be readily determined by one of ordinary skill in the art using conventional dosage determination tests performed on the basis of the foregoing principles.

The above examples can likewise be successful if the reactants and / or operating conditions described in the examples are changed overall or individually.

From the above description, those skilled in the art can easily ascertain the essential features of the present invention, make various changes and modifications to the present invention without departing from the spirit thereof, and And conditions.

[Brief description of the drawings]

FIG. 1 is a graph showing the results of an in vitro neuroprotection assay.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) A61P 25/14 A61P 25/14 25/28 25/28 43/00 111 43/00 111 (72) Inventor John F. Keena 97405 U.S.A., Onyx Street, Eugene, Onyx Street 3854 F-term (reference) 4C206 AA01 AA02 HA31 KA01 MA01 MA04 NA14 ZA01 ZA02 ZA06 ZA16 ZA36 ZC21 ZC35 ZC42

Claims (9)

[Claims] 1. An agent for treating a nervous system disease accompanied by excessive excitation of nerve cells, comprising as an active ingredient N, N'-disubstituted guanidine having high affinity for PCP receptor of nerve cells. 2. The method according to claim 1, wherein the nervous system disease is Alzheimer's disease, Huntington's disease, amyotrophic lateral sclerosis or Down's syndrome. 3. The method according to claim 1, wherein the N, N′-disubstituted guanidine is NMDA.
The therapeutic agent according to claim 1 or 2, which blocks an ion channel of the (N-methyl-d-aspartate) receptor ion-channel complex. 4. The N, N′-disubstituted guanidine has the formula: (Wherein R and R ′ each represent an alkyl group having 4-12 carbon atoms, a cycloalkyl group having 3-12 carbon atoms, 6-18 carbon atoms, and 1-3 Carbocyclic aryl, alkaryl or aralkyl, or heterocyclic compound containing two independent or condensed rings, and R and R ′ can each be substituted at the 1-3 position.) The treatment agent according to any one of claims 1 to 3. 5. The method according to claim 5, wherein the N, N′-disubstituted guanidine is about 10-1.
2. The composition of claim 1, which is administered at a dose of 00 μm / kg (body weight).
4. The therapeutic agent according to any one of 4. 6. An inhibitor of NMDA receptor-ion channel-related neurotoxicity, comprising an N, N'-disubstituted guanidine having a high affinity for a PCP receptor of a nerve cell as an active ingredient. 7. The inhibitor of claim 6, wherein the neurotoxicity is due to excessive release of endogenous glutamate after the onset of ischemic stroke. 8. The N, N′-disubstituted guanidine has the formula: (Wherein R and R ′ each represent an alkyl group having 4-12 carbon atoms, a cycloalkyl group having 3-12 carbon atoms, 6-18 carbon atoms, and 1-3 Carbocyclic aryl, alkaryl or aralkyl, or heterocyclic compound containing two independent or condensed rings, and R and R ′ can each be substituted at the 1-3 position.) The inhibitor according to claim 6 or 7, which is present. 9. The method according to claim 9, wherein the N, N′-disubstituted guanidine is about 10-1.
7. The composition according to claim 6, which is administered at a dose of 00 μm / kg (body weight).
9. The inhibitor according to any one of 8.