8-OHDPAT effects upon cocaine unconditioned and conditioned behaviors: a role for drug stimulus effects.
The effects of the 5-HT1A agonist, (+/-)-8-hydroxy-dipropylaminotetralin (8-OHDPAT) upon the unconditioned and conditioned behavior induced by cocaine were assessed in rats. Separate groups (n=7) received saline, cocaine (10 mg/kg), 8-OHDPAT (0.2 mg/kg), or 8-OHDPAT (0.2 mg/kg) plus cocaine (10 mg/kg) for eight treatment sessions (two per week) in which the rats were tested for 20 min in an open-field. On the eighth treatment session, cocaine enhanced locomotion and rearing but decreased grooming. 8-OHDPAT also decreased grooming and, when given in combination with cocaine, enhanced locomotion but attenuated cocaine-induced rearing. The two 8-OHDPAT groups differed substantially from each other and from the cocaine group in terms of locomotion during the drug treatment phase. Subsequently, all groups received a series of conditioning tests in which they received saline, 0.1, 0.2, or 0.4 mg/kg 8-OHDPAT prior to testing. Groups which had received either 8-OHDPAT or cocaine prior to the conditioning tests exhibited equivalent conditioned effects on the saline conditioning test. When conditioning tests were conducted with 8-OHDPAT, however, only the group which had previously received the combined 0.2 mg/kg 8-OHDPAT plus cocaine treatment exhibited a conditioned response and this effect only occurred at the 0.2 8-OHDPAT dose level. These observations indicate the important influence of the stimulus properties of drugs for the study of drug conditioning and for understanding drug interactions with cocaine.
Carey
Robert J
RJ
Research and Development (151), VA Medical Center and SUNY Health Science Center, 800 Irving Avenue, Syracuse, NY 13210, USA. careyr@cnyrc.org
DePalma
Gail
G
Damianopoulos
Ernest
E
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology*; D000818:Animals; D003042:Cocaine / Q000494:pharmacology*; D003213:Conditioning, Psychological / Q000187:drug effects* / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D008297:Male; D009043:Motor Activity / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley
D004338:Drug Combinations; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D003042:Cocaine