Functional antagonists at the NMDA receptor complex exhibit antidepressant actions.
Inescapable, but not escapable, stress inhibits the induction of Long Term Potentiation (LTP) in the CA1 region of hippocampus, a process that is dependent upon activation of the N-methyl-D-aspartate (NMDA) subtype of glutamate receptor. Since inescapable stress also produces a syndrome of behavioral depression sensitive to clinically effective antidepressants, we examined the actions of functional antagonists at the NMDA receptor complex in animal models commonly used to evaluate potential antidepressants. A competitive NMDA antagonist (2-amino-7-phosphonoheptanoic acid [AP-7]), a non-competitive NMDA antagonist (Dizolcipine [MK-801]), and a partial agonist at strychnine-insensitive glycine receptors (1-aminocylopropanecarboxylic acid [ACPC]) mimicked the effects of clinically effective antidepressants in these models. These findings indicate that the NMDA receptor complex may be involved in the behavioral deficits induced by inescapable stress, and that substances capable of reducing neurotransmission at the NMDA receptor complex may represent a new class of antidepressants. Based on these findings, the hypothesis that pathways subserved by the NMDA subtype of glutamate receptors are involved in the pathophysiology of affective disorders may have heuristic value.
Trullas
R
R
Laboratory of Neuroscience, National Institutes of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892.
Skolnick
P
P
D015763:2-Amino-5-phosphonovalerate / Q000031:analogs & derivatives*; D000596:Amino Acids / Q000494:pharmacology*; D000598:Amino Acids, Cyclic; D000818:Animals; D000928:Antidepressive Agents / Q000494:pharmacology*; D001522:Behavior, Animal / Q000187:drug effects; D001923:Brain Chemistry / Q000187:drug effects; D016291:Dizocilpine Maleate / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D007099:Imipramine / Q000494:pharmacology*; D007103:Immobilization; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009043:Motor Activity / Q000187:drug effects; D018009:Receptors, Glycine; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors* / Q000378:metabolism; D017981:Receptors, Neurotransmitter / Q000378:metabolism; D013315:Stress, Psychological / Q000378:metabolism; D013331:Strychnine / Q000494:pharmacology; D013550:Swimming; D009435:Synaptic Transmission / Q000187:drug effects
D000596:Amino Acids; D000598:Amino Acids, Cyclic; D000928:Antidepressive Agents; D018009:Receptors, Glycine; D016194:Receptors, N-Methyl-D-Aspartate; D017981:Receptors, Neurotransmitter; C023863:1-aminocyclopropane-1-carboxylic acid; D016291:Dizocilpine Maleate; D015763:2-Amino-5-phosphonovalerate; D013331:Strychnine; D007099:Imipramine; C031231:2-amino-7-phosphonoheptanoic acid