An in vivo microdialysis assessment of concurrent MDMA and cocaine administration in Sprague-Dawley rats.
OBJECTIVE
Despite the popularity of polysubstance abuse among recreational methylendioxymethamphetamine (MDMA) users, relatively few controlled experimental studies have documented the neurobehavioral effects of MDMA in combination with other abused substances.


OBJECTIVE
In this study, the combined acute effects of MDMA and cocaine were examined by conducting in vivo microdialysis in the rat nucleus accumbens while simultaneously monitoring locomotor activity.


METHODS
Male Sprague-Dawley rats were administered cocaine (10 or 20 mg/kg, i.p.), MDMA (1.5 or 3.0 mg/kg, i.p.), or one of four combinations of cocaine and MDMA during microdialysis experiments. Locomotor activity was monitored, and dialysis samples were collected every 30 min for 3 h prior to injections, for one 30-min period following saline injections, and for an additional 3-h period following drug injections. Samples were analyzed for dopamine content by high-performance liquid chromatography with electrochemical detection.


RESULTS
Significant differences in locomotor activity and dopamine efflux were found among treatment groups, with some MDMA/cocaine combinations producing significantly greater increases compared to single doses of cocaine or MDMA within the first 30 min after injection.


CONCLUSIONS
Considering the popularity of polysubstance use among recreational MDMA users, the clinical implications of the current findings warrant further investigation.
Panos
John J
JJ
Department of Psychology, Western Michigan University, Kalamazoo, MI 49008, USA.
Baker
Lisa E
LE
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D002851:Chromatography, High Pressure Liquid; D003042:Cocaine / Q000008:administration & dosage / Q000633:toxicity*; D004298:Dopamine / Q000378:metabolism; D018765:Dopamine Uptake Inhibitors / Q000008:administration & dosage / Q000633:toxicity; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D006213:Hallucinogens / Q000008:administration & dosage / Q000633:toxicity; D008297:Male; D017551:Microdialysis; D009043:Motor Activity / Q000187:drug effects*; D018817:N-Methyl-3,4-methylenedioxyamphetamine / Q000008:administration & dosage / Q000633:toxicity*; D009714:Nucleus Accumbens / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
D018765:Dopamine Uptake Inhibitors; D006213:Hallucinogens; D003042:Cocaine; D018817:N-Methyl-3,4-methylenedioxyamphetamine; D004298:Dopamine