Alterations in the functional activity and/or number of serotonin2 (5-HT2) and/or serotonin1C (5-HT-1c) receptors have been implicated in the pathophysiology of a large number of mental illnesses including obsessive- compulsive disorder, schizophrenia, depression, anxiety, dysthymia, suicide, aggression and eating disorders. Additionally, a number of psycho- and neuropharmacologic agents including antidepressants (mianserin, amitriptyline, imipramine), antipsychotic drugs (loxapine, clozapine), hallucinogens (lysergic acid diethylamide) and anti-dysthymic agents (ritanserin) bind to 5-HT2 and 5-HT-1c receptors. Determining the precise roles the 5-HT2 and 5-HT-1c receptors have in mediating the effects of these agents is difficult because no truly subtype selective agents are currently available. Insights we gain in understanding how drugs bind to each of these receptors should enhance our ability to design novel receptor-specific agents which can be used to treat mental illnesses. This proposal will determine how agonists and antagonists bind to 5-HT2 and 5-HT-1c receptors. We will utilize the techniques of molecular biology and receptor pharmacology to identify specific amino acids essential for specifying the ligand binding domains of each receptor. We are utilizing four major techniques. (1) chimeric protein construction (2) site directed mutagenesis, (3) molecular modelling and (4) structural biochemical measurements. Our strategy is to test three-dimensional molecular models of 5- HT2 and 5- HT-1c receptor-ligand interactions using a combination of molecular biological and structural-biochemical techniques. We will also take advantage of unique mutations we have produced to probe the molecular details responsible for hallucinogen- induced alterations of serotonin receptors in vitro. These findings will be useful for the design and synthesis of new medications to treat psychiatric diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM052213-02
Application #
2191153
Study Section
Molecular, Cellular, and Developmental Neurobiology Review Committee (MCDN)
Project Start
1994-07-01
Project End
1997-06-30
Budget Start
1995-07-01
Budget End
1996-06-30
Support Year
2
Fiscal Year
1995
Total Cost
Indirect Cost
Name
Case Western Reserve University
Department
Psychiatry
Type
Schools of Medicine
DUNS #
077758407
City
Cleveland
State
OH
Country
United States
Zip Code
44106
Roth, B L; Meltzer, H Y; Khan, N (1998) Binding of typical and atypical antipsychotic drugs to multiple neurotransmitter receptors. Adv Pharmacol 42:482-5
Roth, B L; Willins, D L; Kristiansen, K et al. (1998) 5-Hydroxytryptamine2-family receptors (5-hydroxytryptamine2A, 5-hydroxytryptamine2B, 5-hydroxytryptamine2C): where structure meets function. Pharmacol Ther 79:231-57
Roth, B L; Choudhary, M S; Khan, N et al. (1997) High-affinity agonist binding is not sufficient for agonist efficacy at 5-hydroxytryptamine2A receptors: evidence in favor of a modified ternary complex model. J Pharmacol Exp Ther 280:576-83
Roth, B L; Shoham, M; Choudhary, M S et al. (1997) Identification of conserved aromatic residues essential for agonist binding and second messenger production at 5-hydroxytryptamine2A receptors. Mol Pharmacol 52:259-66
Palvimaki, E P; Roth, B L; Majasuo, H et al. (1996) Interactions of selective serotonin reuptake inhibitors with the serotonin 5-HT2c receptor. Psychopharmacology (Berl) 126:234-40
Berry, S A; Shah, M C; Khan, N et al. (1996) Rapid agonist-induced internalization of the 5-hydroxytryptamine2A receptor occurs via the endosome pathway in vitro. Mol Pharmacol 50:306-13
Roth, B L; Palvimaki, E P; Berry, S et al. (1995) 5-Hydroxytryptamine2A (5-HT2A) receptor desensitization can occur without down-regulation. J Pharmacol Exp Ther 275:1638-46
Choudhary, M S; Sachs, N; Uluer, A et al. (1995) Differential ergoline and ergopeptine binding to 5-hydroxytryptamine2A receptors: ergolines require an aromatic residue at position 340 for high affinity binding. Mol Pharmacol 47:450-7
Roth, B L; Tandra, S; Burgess, L H et al. (1995) D4 dopamine receptor binding affinity does not distinguish between typical and atypical antipsychotic drugs. Psychopharmacology (Berl) 120:365-8