COCAINE AND COCAETHYLENE - EFFECTS ON EXTRACELLULAR DOPAMINE IN THE PRIMATE

Cocaine and cocaethylene (a psychoactive metabolite of concurrent coca ine and ethanol consumption) were studied in the anesthetized vervet m onkey. The ability of each to elevate extracellular DA in the caudate nucleus was assessed using microdialysis probes acutely lowered throug h chronic guide cannulae. Blood samples were also collected to determi ne plasma levels of the two drugs. Doses of 1.5 mu mol/kg cocaine (equ ivalent to 0.5 mg/kg cocaine-HCl) and cocaethylene were administered i ntravenously. Microdialysis and blood samples were collected at 5-min intervals immediately following drug administration. Both drugs caused a maximal four-fold increase in extracellular DA during the 5- to 10- min period following drug administration. This is the first report of cocaine (and cocaethylene) induced alterations in extracellular DA in primates. The abilities of cocaine and cocaethylene to produce euphori a are being compared in ongoing clinical research studies. The potenti al use of these results for interpreting the neurochemical basis of an y differences in those studies is discussed.