Loss of nicotine-induced effects on locomotor activity in fetal alcohol-exposed rats

Previous evidence from our laboratory showed that systemic injection of nic otine enhanced attention and memory in control rats, but not fetal alcohol- exposed (FAE) rats. The present study examined the effects of nicotine on t wo measures of locomotor activity in FAE rats. Subjects were 2-month-old ma le offspring of Sprague-Dawley rats fed a 35% ethanol-derived caloric diet, a pair-fed sucrose diet, or a chow-fed diet during the last 2 weeks of ges tation. The two experiments examined the effects of intraperitoneal injecti on of saline or nicotine (0.25 or 0.75 mg/kg) on rearing in an operant cham ber and locomotor activity in an open field for 60 min. The high dose of ni cotine produced a decrease in rearing in the first 10-min period, followed by a later increase in rearing in the pair-fed and chow-fed groups, but not the FAE group. Nicotine also produced an elevation of locomotor activity i n the open field in only the two control groups. These findings provide add itional evidence that FAE rats show less behavioral responsiveness to nicot ine. (C) 1999 Elsevier Science Inc. All rights reserved.