Conditioned saccharin aversion induced by self-administered cocaine negatively correlates with the rate of cocaine self-administration in rats.
Previous studies showed that the degree of saccharin aversion induced by a self-administered drug correlated with the amount of drug taken. The present paradigm evaluated the relationship between conditioned saccharin (0.15% w/w) aversion and cocaine self-administration (0.15 mg/kg per injection) when drug intake was limited to 1 mg/kg per session over five taste-drug pairings. The low dose of self-administered cocaine induced a significant decrease in saccharin intake as a result of the conditioning pairings. In addition, conditioned saccharin intake was significantly correlated with the rate of cocaine self-administration (r=-0.54; P<0.05). A second experiment was designed to control for the effect of cocaine concentration in blood per unit of time. Saccharin was paired with one of three doses of non-contingent IV cocaine (0, 1, 3, 5 mg/kg) over five taste-drug pairings. Although, 3 or 5 mg/kg of non-contingent IV cocaine induced a dose-dependent decrease in saccharin intake after five taste-drug pairings, the low dose of 1 mg/kg was not effective in inducing the effect. Taken together, these results suggest that 1 mg/kg per session of cocaine was effective in inducing saccharin aversion only in rats that self-administered the drug at a high rate. It is suggested that a Pavlovian effect such as conditioned saccharin aversion induced by a self-administered drug may be an alternative tool to investigate the anticipation of addictive drugs.
Department of Pharmacology, University of Michigan, Ann Arbor 48109-0632, USA. felipeg@umich.edu
Felipe
F
Gomez
D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects*; D003042:Cocaine / Q000494:pharmacology*; D019970:Cocaine-Related Disorders / Q000523:psychology*; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D007279:Injections, Subcutaneous; D008297:Male; D008892:Milk; D051381:Rats; D017207:Rats, Sprague-Dawley; D012054:Reinforcement, Psychology; D012439:Saccharin / Q000494:pharmacology; D012646:Self Administration; D013549:Sweetening Agents / Q000494:pharmacology; D013649:Taste / Q000187:drug effects*
D018765:Dopamine Uptake Inhibitors; D013549:Sweetening Agents; D012439:Saccharin; D003042:Cocaine