title: Effects of lead on temporally-spaced responding in rats.
abstract: The effects of lead acetate and aging on temporally-spaced responding (differential reinforcement of low rate or DRL-20 seconds) were studied. Three groups of animals were considered along with their respective controls. Neonate-treated Long-Evans rats were orally intubated with 200 mg/kg lead acetate from the third to 30th day after birth. Some of these animals were tested at 3 months (adult group) and some at 21 months (geriatric group) of age. A continuously treated group was exposed to 250 ppm lead in utero and throughout their life after birth and was treated at 8 months of age. Lead-treated animals exhibited a more variable response to d-amphetamine and a more pronounced number of IRTs in the first class interval. Aging shifted the pentobarbital dose-response curve to the left in both control and lead-treated animals and flattened interresponse time (IRT) distributions.
mesh_terms: D000375:Aging; D000818:Animals; D000831:Animals, Newborn; D003216:Conditioning, Operant / Q000187:drug effects*; D003913:Dextroamphetamine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D007854:Lead / Q000494:pharmacology*; D008297:Male; D010424:Pentobarbital / Q000494:pharmacology; D051381:Rats; D012055:Reinforcement Schedule; D013997:Time Factors
chemical_list: D007854:Lead; D010424:Pentobarbital; D003913:Dextroamphetamine