The behavioral effects of nicotine were compared with those of its metabolites, nornicotine and cotinine, in beagle dogs and squirrel monkeys. Subjects responded under a multiple fixed-interval (FI) 300-sec, fixed-ratio (FR) 30 response schedule of food presentation. Nicotine (0.01-1.0 mg/kg i.m.) and nornicotine (0.03-3.0 mg/kg i.m.) produced qualitatively similar effects in both dogs and monkeys. Nicotine produced dose-related increases, then decreases in rates of responding during FI components; rates of responding during FR components were only decreased. Nornicotine produced only dose-dependent decreases in responding during both FI and FR components. In the dogs, cotinine (0.01-10.0 mg/kg i.m.) produced only dose-dependent decreases in rates of responding during both FI and FR components. In the squirrel monkeys, however, cotinine (0.1-3.0 mg/kg i.m.) increased responding during FI components; a high dose of 30.0 mg/kg decreased responding during both FI and FR components. The behavioral effects of cocaine (0.03-3.0 mg/kg i.m.) and its metabolite norcocaine (0.01-1.0 mg/kg i.m.) were compared in the dogs. FI rates of responding first increased and then decreased with increasing doses of each drug, whereas FR rates of responding only decreased in a dose-related manner. Norcocaine was slightly more potent than cocaine in producing these effects on schedule-controlled responding in dogs. These experiments indicate the metabolites of nicotine and cocaine are behaviorally active and may contribute to the pharmacological profile of the parent compounds.
|Original language||English (US)|
|Number of pages||7|
|Journal||Journal of Pharmacology and Experimental Therapeutics|
|State||Published - Jan 1 1985|
ASJC Scopus subject areas
- Molecular Medicine