| Abstract: | Adult male rats (Rattus norvegicus) were exposed to a water supply in the home cage containing 100 ppm cadmium chloride and sodium saccharin (.65% wt/vol; cadmium group) or water containing only the saccharin amendment (group control). On Day 65 of exposure, animals from each group received jugular catheter implants and were subsequently trained over the course of 15 daily 2-hr sessions to self-administer a .25 mg/kg/infusion of cocaine HCl under a fixed ratio 1 schedule. Immediately following acquisition training, the full dose-effect function was determined for all animals by using cocaine doses of .03, .06, .125, .25, .50, and 1.0 mg/kg. Cadmium-exposed animals executed more active (cocaine) lever responses during acquisition training but were not different from controls in depressing a pharmacologically inactive lever. For dose-effect testing, cadmium exposed animals exhibited greater self-administration than controls at the higher doses of cocaine, and there was evidence that the cocaine dose that produced maximum responding was higher in cadmium-exposed than control animals. (PsycINFO Database Record (c) 2010 APA, all rights reserved) |
