Maternal isolation during the first two postnatal weeks affects novelty-induced responses and sensitivity to ethanol-induced locomotor activity during infancy

MS FERNÁNDEZ; NIZHNIKOV ME; SPEAR, N.E.; ABATE P; PAUTASSI RM

DEVELOPMENTAL PSYCHOBIOLOGY

JOHN WILEY & SONS INC

Lugar: New York; Año: 2014 vol. 56 p. 1070 - 1082

0012-1630

Abstract Animals exposed to chronic maternal separation exhibit enhanced ethanol self-administration and greater hormonal and behavioral responsiveness to stress in adulthood. Whether the effects of maternal separation are immediately evident in infancy or whether they appear only later on development is still an unanswered question This study tested sensitivity to ethanol?s behavioral stimulating effects in infant rats that experienced maternal separation (MS) from postnatal day 1 to 14. MS infants exhibited significantly greater reactivity to the motor stimulating effects of 1.25 g/kg ethanol than control animals, yet greater motor suppression after 2.5 g/kg ethanol. Baseline level of response to novelty was altered in MS infants, in a nor-binaltorphimine insensitive manner, i.e., despite modified activity of the kappa-opioid system. These results indicate that the consequences of chronic maternal isolation emerge early in ontogeny, affecting ethanol sensitivity in infancy.