LEAD ETHANOL INTERACTIONS .1. RATE-DEPRESSANT EFFECTS

Adult male rats were exposed to a diet containing 500 ppm added lead a s lead acetate (group lead-diet) or a control diet containing no added chemicals (group control-diet) for 61 days prior to commencing fixed- ratio 32 (FR 32) lever press training for water reinforcement. After s teady state responding was achieved, all animals received serial admin istrations of acute doses of ethanol prior to the daily training sessi on. Specifically, lead-diet and control-diet rats received i.p. inject ions of .25, .5, .75, 1.0, and 1.25 g/kg ethanol, in ascending order, alternating daily with injections of saline. The results revealed a do se-dependent rate-depressant effect, with higher doses of ethanol prod ucing more behavioral suppression than lower doses for both groups. In addition, at the dose of 1.0 g/kg it was observed that the suppressiv e effects of ethanol on schedule-controlled responding were reduced am ong lead-treated animals relative to controls. These data are discusse d in terms of lead-induced attenuation of the pharmacologic effects of ethanol.