Allosteric modulators of the NMDA receptor and their use in the treatment of CNS disorders and enhancement of CNS function

Abstract

Novel compounds and compositions for modulating NMDA receptor function comprising Conantokin-G and derivatives thereof; methods for modulating NMDA receptor function and methods for treating neuropsychopharmacological disorders, using the novel compounds and compositions of the invention; and a method for screening compounds capable of binding to a novel allosteric modulatory site, are described.

1 . A method for treating excitotoxicity resulting from over-stimulation of the NMDA receptor which comprises administering to a patient in need thereof a therapeutically effective amount of an active agent selected from the group consisting of Conantokin-T and pharmaceutically acceptable salts thereof, wherein Conantokin-T has the formula Gly-Glu-Xaa 1 -Xaa 2 -Tyr-Gln-Lys-Met-Leu-Xaa 1 -Asn-Leu-Arg-Xaa 1 -Ala-Glu-Val-Lys-Lys-Asn-Ala (SEQ ID NO:2)where Xaa 1  and Xaa 2  are each γ-carboxy-glutamic acid.  
     
     
         2 . The method of  claim 1 , wherein said excitotoxicity is associated with epilepsy or epileptic seizure.  
     
     
         3 . The method of  claim 1 , wherein said excitotoxicity is associated with brain ischemia caused by stroke or traumatic injury.  
     
     
         4 . The method of  claim 1 , wherein said treatment protects neurons from excitotoxic death.  
     
     
         5 . A method for treating a neuropsychopharmacological disorder resulting from over-stimulation of the NMDA receptor which comprises administering to a patient in need thereof a therapeutically effective amount of selected from the group consisting of Conantokin-T and pharmaceutically acceptable salts thereof an active agent, wherein Conantokin-T has the formula Gly-Glu-Xaa 1 -Xaa 2 -Tyr-Gln-Lys-Met-Leu-Xaa 1 -Asn-Leu-Arg-Xaa 1 -Ala-Glu-Val-Lys-Lys-Asn-Ala (SEQ ID NO:2) where Xaa 1  and Xaa 2  are each γ-carboxy-glutamic acid.  
     
     
         6 . The method of  claim 5 , wherein said disorder is selected from the group consisting of chemical toxicity, neurodegenerative disorder, mood disorder and depression.  
     
     
         7 . The method of  claim 6 , wherein said disorder is a mood disorder selected from the group consisting of bipolar disorder, dysthymia and seasonal affective disorder.  
     
     
         8 . The method of  claim 6 , wherein said disorder is a neurodegenerative disorder selected from the group consisting of Huntington's disease, Parkinson's disease and Alzheimer's disease.  
     
     
         9 . The method of  claim 6 , wherein said disorder is chemical toxicity selected from the group consisting of substance tolerance and addiction.  
     
     
         10 . A method for treating excitotoxicity resulting from over-stimulation of the NMDA receptor which comprises administering to a patient in need thereof a therapeutically effective amount of an active agent selected from the group consisting of Conantokin-T, Conantokin-G, a Conantokin-G derivative and pharmaceutically acceptable salts thereof, wherein Conantokin-T has the formula Gly-Glu-Xaa 1 -Xaa 2 -Tyr-Gln-Lys-Met-Leu-Xaa 1 -Asn-Leu-Arg-Xaa 1 -Ala-Glu-Val-Lys-Lys-Asn-Ala (SEQ ID NO:2) and Conantokin-G has the formula Gly-Glu-Xaa 1 -Xaa 2 -Leu-Gln-Xaa 1 -Asn-Gln-Xaa 1 -Leu-Ile-Arg-Xaa 1 -Lys-Ser-Asn (SEQ ID NO: 1) where Xaa 1  and Xaa 2  are each γ-carboxy-glutamic acid and wherein said Conantokin-G derivative is an antagonist of the NMDA receptor and has the following formula: 
       A 1 -A 2 -A 3 -A 4 -A 5 -A 6 -(A 7 ) x   c [A 8 -(A 9 -A 10 ) x   d —NH 2 ] n   
       wherein 
 A 1  is glycine, alanine, valine, leucine or isoleucine;  
 A 2  is glutamic acid, aspartic acid, γ-carboxyglutamate (Gla), 3-carboxyaspartic acid, D-glutamic acid, phosphoserine or phosphothreonine;  
 A 3  is glutamic acid, aspartic acid, γ-carboxyglutamate (Gla), 3-carboxyaspartic acid, D-glutamic acid, phosphoserine or phosphothreonine;  
 A 4  is Gla;  
 A 5  is glycine, alanine, valine, leucine or isoleucine;  
 A 6  is a peptide of 7-9 amino acids;  
 A 7  is an amino acid selected from the group consisting of natural, modified or non-natural amino acids;  
 A 8  is lysine or arginine;  
 A 9  is an amino acid selected from the group consisting of natural, modified or non-natural amino acids;  
 A 10  is an amino acid selected from the group consisting of natural, modified or non-natural amino acids;  
 x c  and x d  are independently 0 or 1; and  
 n is 0 or 1, wherein said treatment protects neurons from excitotoxic death.