Maternal separation has no effect on voluntary ethanol intake in female Wistar rats

Abstract 

Adverse experiences, early in life or during adulthood, can increase the vulnerability for development of drug dependence. Investigators have shown that short and prolonged periods of maternal separation during the postnatal period can affect voluntary ethanol intake in male rats. Recent study findings have indicated sex-dependent effects of maternal separation, and, in the current study, the effects of maternal separation on acquisition of voluntary ethanol intake in female Wistar rats were investigated. Rat pups were subjected to daily maternal separation for 15 min (MS15) or 360 min (MS360) during the first 3 weeks of life or reared under normal animal facility rearing (AFR) conditions. During 25 days, starting at 10 weeks of age, the effects of maternal separation on acquisition of voluntary ethanol intake were investigated. In contrast with previous study results for male rats, neither MS15 nor MS360 affected acquisition of voluntary ethanol intake in female rats. A stressful situation in adulthood, restraint stress, resulted in a significant increase in ethanol intake during the restraint period compared with baseline levels in the animals reared under normal AFR conditions, an effect that persisted throughout the postrestraint period. In rats subjected to MS15 or MS360, a significant increase in ethanol intake was shown during the postrestraint period compared with baseline levels. The current study findings therefore give further evidence for sex differences in the consequences of maternal separation. Compared with previous findings in male rats, acquisition of ethanol intake was not affected, and restraint-induced effects were less pronounced but more prolonged, in female rats.

Keywords: Stress, Handling, Environmental manipulation, Maternal deprivation, Alcohol, Restraint stress, Sex differences