Behavioral sensitization to cocaine, but not cocaine-conditioned behavior, is associated with increased dopamine occupation of its receptors in the nucleus accumbens.
Rats had repeated treatments with cocaine associated with a specific context (paired group). Evidence for classical conditioning of cocaine's motor-activity effects and context-specific behavioral sensitization to cocaine was obtained, relative to vehicle-treated (control) and pseudoconditioned (unpaired) groups. Only the paired group exhibiting context-specific behavioral sensitization had more dopamine bound to both D1-like and D2-like receptors in the nucleus accumbens than did rats in the control group receiving cocaine on the test day. No effects on receptor occupation were found in rats showing a classical conditioned response to a context previously paired with cocaine. Thus, sensitization to cocaine, but not classical conditioning of cocaine's behavioral effects, was associated with greater dopaminergic neurotransmission selectively in the nucleus accumbens.
Burechailo
L
L
Department of Psychology, University of Alberta, Edmonton, Canada.
Martin-Iverson
M T
MT
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D003042:Cocaine / Q000494:pharmacology*; D003214:Conditioning, Classical; D004298:Dopamine / Q000032:analysis* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D008297:Male; D009043:Motor Activity / Q000187:drug effects* / Q000502:physiology; D009714:Nucleus Accumbens / Q000737:chemistry* / Q000187:drug effects*; D011804:Quinolines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011954:Receptors, Dopamine / Q000187:drug effects* / Q000378:metabolism
D011804:Quinolines; D011954:Receptors, Dopamine; C000470:EEDQ; D003042:Cocaine; D004298:Dopamine