Methods of identifying inverse agonists of the serotonin 2A receptor

Abstract

The present invention relates to a method of identifying compounds which act as inverse agonists of the 5-HT2A receptor, the method comprising contacting a constitutively active 5-HT2A receptor with at least one test compound and determining any decrease in the level of basal activity of the receptor so as to identify a test compound which is an inverse agonist of the 5-HT2A receptor. Such inverse agonists may be used in the treatment of schizophrenia and related psychoses.

1 . A method of identifying a compound which is an inverse agonist of the 5-HT2A receptor, the method comprising: 
 (a) contacting a constitutively active 5-HT2A receptor with at least one test compound; and    (b) determining any decrease in basal activity level of the 5-HT2A receptor so as to identify a test compound which is an inverse agonist of the 5-HT2A receptor.    
     
     
         2 . A method of identifying a compound which is an inverse agonist of the 5-HT2A receptor, the method comprising: 
 (a) culturing cells which express a constitutively active 5-HT2A receptor;    (b) incubating the cells with at least one test compound; and    (c) determining any decrease in basal activity level of the 5-HT2A receptor so as to identify a test compound which is an inverse agonist of the 5-HT2A receptor.    
     
     
         3 . The method of  claim 2 , wherein the cells of step (a) overexpress said 5-HT2A receptor.  
     
     
         4 . The method of  claim 2 , wherein the identified inverse agonist is selective for the 5-HT2A receptor.  
     
     
         5 . A method of identifying mutation(s) in a gene encoding a constitutively active 5-HT2A receptor, the method comprising: 
 (a) extracting nucleic acid from a biological sample obtained from an individual having a disorder or condition putatively associated with constitutive activity of the 5-HT2A receptor;    (b) preparing cDNA from the extracted nucleic acid;    (c) selecting from the cDNA in step (b) cDNA encoding the 5-HT2A receptor;    (d) transfecting a cell with an expression vector comprising said selected cDNA;    (e) selecting a cell expressing constitutively active 5-HT2A receptor; and    (f) sequencing the cDNA in said selected cell to detect the mutation(s).    
     
     
         6 . The method of  claim 5 , wherein said biological sample comprises blood, platelets or brain tissue.  
     
     
         7 . The method of  claim 5 , wherein the extracted nucleic acid is RNA.  
     
     
         8 . The method of  claim 5 , further comprising prior to said transfecting step amplifying the cDNA.  
     
     
         9 . The method of  claim 5 , wherein said cDNA selection is performed using one or more oligodeoxynucleotide probes specific to the gene encoding the 5-HT2A receptor.  
     
     
         10 . A method of diagnosing a disorder or condition, or a susceptibility thereto, associated with constitutive activity of the 5-HT2A receptor, the method comprising: 
 (a) obtaining a biological sample from an individual putatively affected by or susceptible to a disorder or condition associated with constitutive activity of the 5-HT2A receptor;    (b) isolating from said biological sample a nucleic acid sequence encoding said receptor, or a portion of said nucleic acid sequence corresponding to the portion of the gene identified to include mutation(s) by the method of  claim 5;  and    (c) detecting the presence or absence of mutation(s) in said nucleic acid sequence or said portion thereof.    
     
     
         11 . The method of  claim 10 , wherein said biological sample comprises blood, platelets or brain tissue.  
     
     
         12 . A test kit for detecting mutation(s) in a gene encoding a constitutively active 5-HT2A receptor, the test kit comprising a nucleic acid sequence corresponding to a portion of the gene identified by the method of  claim 5  to include at least one mutation.  
     
     
         13 . A method of decreasing the basal activity level of the 5-HT2A receptor in a subject in need thereof, the method comprising contacting a 5-HT2A receptor in said subject with an inverse agonist of the 5-HT2A receptor in an amount effective to substantially decrease the basal activity level of said receptor.  
     
     
         14 . The method of  claim 13 , wherein the inverse agonist is selective for the 5-HT2A receptor.  
     
     
         15 . The method of  claim 13 , wherein the inverse agonist has little or substantially no anti-dopaminergic activity.  
     
     
         16 . A method of ameliorating symptoms of schizophrenia or psychosis in a subject in need thereof, the method comprising administering to the subject a therapeutically effective amount of an inverse agonist of the 5-HT2A receptor.  
     
     
         17 . Use of an inverse agonist of the 5-HT2A receptor for the preparation of a medicament for substantially decreasing the basal activity level of a constitutively active 5-HT2A receptor.  
     
     
         18 . Use according to  claim 17 , wherein the inverse agonist is selective for the 5-HT2A receptor.  
     
     
         19 . Use according to  claim 17 , wherein the inverse agonist has little or substantially no anti-dopaminergic activity.  
     
     
         20 . Use of a 5-HT2A receptor to identify a compound acting as an inverse agonist at said receptor.  
     
     
         21 . Use of a 5-HT2A receptor to identify a compound acting as an inverse agonist at said receptor and useful in the treatment of schizophrenia or psychosis.