Reproductive experience alters brain Plasticity and spatial memory in response to mother-pup separation stress during the Postpartum period

RIVAROLA, M.A.; SUAREZ, M.; AGUGGIA, J.P.

Buenos Aires

Congreso; REUNIÓN CONJUNTA DE SOCIEDADES DE BIOCIENCIAS; 2017

In mammals, substantial behavioral and neurobiological changes occur throughout the female brain because of reproductive experience (RE: pregnancy, parturition, and mothering). This structural and functional modification remodels the neural circuits of the hippocampus and have a significant impact in learning and memory aspects. Since levels of hippocampal neurogenesis vary in response to a wide range of intrinsic and extrinsic factors, we considered the possibility that neurogenesis is deviated during RE, thus providing potential explanation for the changes in maternal cognitive performance during that period. Female Wistar rats were divided in the following experimental groups: Nulliparous (NP: none RE), Primiparous (PRI: one RE) and Multiparous (MULT: two RE). The PRI and MULT group were subjected to either animal facility rearing (C) or daily 4,5h of separation from pups (S) from postpartum day (PPD) 1 to 21. Spatial memory was evaluated in the Barnes Maze (PPD 21-26). To quantified cell survival dams were injected with bromodeoxyuridine (BrdU) on PPD1 and euthanized 21 days later. To evaluate cell proliferation were injected PPD21 and euthanized 24h later. Neurogenesis were also analyzed in Age-matched NP females. The results revealed that MULT and PRI-C dams show a better performance in spatial memory than PRI-S and NP females demonstrated by less errors in their search during the probe trial (p≤0.02), PRI-C and MULT-C spent more time in the goal sector than NP and S dams (p