BEHAVIORAL DEFICITS INDUCED BY BINGELIKE EXPOSURE TO ALCOHOL IN NEONATAL RATS - IMPORTANCE OF DEVELOPMENTAL TIMING AND NUMBER OF EPISODES

The importance of the timing and number of episodes of bingelike alcoh ol exposure in neonatal rats on subsequent behavioral outcomes was eva luated with a parallel bar task and a spatial conditional alternation task. Different groups of Sprague-Dawley rat pups were exposed to alco hol delivered via artificial rearing procedures either on postnatal Da ys (PD) 4 and 5, on PD 8 and 9, or on both PD 4/5 and 8/9 (Combined), producing daily peak blood alcohol concentrations around 400 mg/dl. Co ntrols included an artificially reared group and a normally reared gro up. Exposure during PD 4/5 produced significantly more severe motor de ficits and significantly more severe reductions in cerebellar and brai nstem weights than did exposure on PD 8/9. Combined exposure produced greater deficits on these measures than either of the limited exposure s. Significant deficits in the acquisition rates for conditional alter nation were found only with the Combined exposure, although both the P D 8/9 and Combined groups committed significantly more within-trial er rors. All three alcohol treatments produced significant and comparable reductions in forebrain weight. The type and severity of behavioral a nd neural deficits induced by neonatal bingelike alcohol exposure depe nd on the timing and number of exposures. (C) 1996 John Wiley & Sons, Inc.