Maternal Separation affects neurocircuitry of ether and restraint stress in adulthood

Abstract

We investigated the effect of maternal separation on neural circuitry activation in response to stress in adulthood. Rats were submitted to maternal separation (180 min/day) during 2 first weeks of life. Two stress protocols were randomly performed at 10–12 weeks of age. 1) Restraint animals were placed into plastic tubes for 20 min or 2) exposed to ether for 10 min. After 90 min of the onset of stress situation rats were euthanized and brains were removed and processed for cFos immunohistochemistry in paraventricular (PVN), amygdaloid medial (AM), supraoptic nucleus (SO) and preoptic area (POA). Cathecolaminergic nucleus of brainstem tyrosine hydroxilase was also co‐localized. Maternal separation increased Fos activated neurons in both stress situations in most of nuclei evaluated, especially after ether stress. The number of neurons Fos positive was 180% higher on Locus Coeruleus (LC), 136% PVN and 170% APO after ether stress when compared to control group. On the other hand on restrain stress was 86% in LC, 125% in PVN, and 56% in APO higher. Maternal separation only affect activation in SO after restraint stress (73%). AM showed a similar response on both stress protocols (about 135% higher). Our data showed that maternal separation induces a heterogenic response on neural circuitry activation and interferes with the neuroendocrine programming early in life.Financial support CNPq, Fapemig