NMDA RECEPTOR ANTAGONISTS ENHANCE 5-HT2 RECEPTOR-MEDIATED BEHAVIOR, HEAD-TWITCH RESPONSE, IN MICE

The purpose of this study was to characterize behavioral interactions between glutamatergic and serotonergic 5-HT2 receptors. Both competiti ve (AP-5 [D-2-amino-5 -phosphovalerate] and D-CPP [3-(2carboxypiperazi ne-4yl)-propylphosphonate]) and noncompetitive (MK-801 [dizocilpine], ketamine, dextrorphan and dextromethorphan) N-methyl-D-aspartate (NMDA ),receptor antagonists markedly enhanced a selective serotonergic beha vior, the head twitch response (HTR), in mice. In contrast, NMDA itsel f inhibited 5-hydroxytryptamine (5-HT)-induced HTR in mice. These resu lts suggest that glutamatergic neurotransmission may modulate serotone rgic function at the 5-HT2 receptor.