Scopolamine does not differentially affect Morris maze performance in adult rats exposed prenatally to alcohol

Abstract

Rats exposed prenatally to alcohol have shown deficits in spatial learning in radial-arm and Morris mazes. Prenatal exposure to alcohol in rats has also been shown to alter central nervous system (CNS) cholinergic function. Since cholinergic dysfunction disrupts spatial learning in normal rats, the present experiment assessed the role of putative prenatal alcohol-induced cholinergic dysfunction in spatial learning in rats. Pregnant rats were fed alcohol via liquid diet from gestation day 6 to 20. Control dams were pair-fed liquid diet without alcohol or fed ad lib lab chow and water. Group housed adult male and female offspring (postnatal days 110 to 135) were given scopolamine-HCl (o, 0.5, or 1.0 mg/kg/day) and tested in a Morris maze, with four trials per day for four days. A 15-s probe trial preceded testing on days 2–4. On day 5, the rats were given four trials to learn a new platform location. Scopolamine produced dose-dependent increases in latency to find the platform for all groups. There were no significant differences among prenatal treatment groups in scopolamine-induced shifts in performance. The results did not support the hypothesis that prenatal alcohol-induced CNS cholinergic dysfunction is related to spatial learning performance in these rats.