Characterization of the role of medial prefrontal cortex dopamine receptors in cocaine-induced locomotor activity.
Medial prefrontal cortex (mPFC) dopamine (DA) modulates the motor-stimulant response to cocaine. The present study examined the specific mPFC DA receptor subtypes that mediate this behavioral response. Intra-mPFC injection of the DA D2-like receptor agonist quinpirole blocked cocaine-induced motor activity, an effect that was prevented by coadministration of the D2 receptor antagonist sulpiride. Intra-mPFC injection of the selective D4 receptor agonist PD 168,077 or the selective D1 receptor agonist SKF 81297 did not alter the motor-stimulant response to cocaine. Finally, it was found that an intermediate dose of quinpirole, which only attenuated cocaine-induced motor activity, was not altered by SKF 81297 coadministration, suggesting a lack of synergy between mPFC D1 and D2 receptors. These results suggest that D2 receptor mechanisms in the mPFC are at least partly responsible for mediating the acute motor-stimulant effects of cocaine.
Beyer
C E
CE
Department of Pharmacology and Therapeutics, School of Graduate Studies, Louisiana State University Health Sciences Center, USA.
Steketee
J D
JD
D000818:Animals; D001931:Brain Mapping; D003042:Cocaine / Q000494:pharmacology*; D007267:Injections; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D017397:Prefrontal Cortex / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017448:Receptors, Dopamine D2 / Q000187:drug effects*
D017448:Receptors, Dopamine D2; D003042:Cocaine