EFFECTS OF ACUTE D-CPPENE ON MESOACCUMBENS DOPAMINE RESPONSES TO NICOTINE IN THE RAT

Acute administration of the NMDA receptor antagonist, D-CPPene (SDZ EA A 494; -(2-carboxypiperazin-4-yl)-1-propenyl-1-phosphonic acid; 2 mg/k g), abolished (P < 0.01) the sensitised mesoaccumbens dopamine respons e to nicotine (0.4 mg/kg) measured using in vivo microdialysis, but no t the increased locomotor activity, observed in rats pretreated with n icotine prior to the test day. D-CPPene enhanced (P < 0.01) the mesoac cumbens dopamine response, but not the locomotor response, to acute ni cotine given to drug-naive rats. The data suggest that sensitised meso accumbens dopamine responses to nicotine involve co-stimulation of NMD A receptors but that this effect is not closely related to sensitisati on of the locomotor response to the drug.