Differential responses to prenatal and postnatal experiences in the adult rat

VG. BARROS, ID. MARTIJENA, P. RODRIGUEZ, AA. PEREZ, VA. MOLINA Y MC. ANTONELLI

Portland, Oregon. EE.UU.

Congreso; 37th Annual Meeting. American Society for Neurochemistry; 2006

American Society for Neurochemistry

Repeated restraint during the last week of pregnancy was used as a model of prenatal stress, and adoption at birth was used to change the postnatal environment. Adult offsprings of rats stressed during pregnancy (S) exhibited a decrease in benzodiazepine receptors (BDZ) binding sites in the central amygdala (Ce), CA1, CA3 and dentate gyrus (DG) areas of the hippocampus. The levels of BDZ receptors seems to be predictive of an anxiogenic behaviour that can be demostrated in the elevated plus maze (EPM). Adult offsprings of rats stressed during pregnancy (S) exhibited higher levels of anxiety than control rats (C). When analyzing the cross-fostering model we found that adoption per se (C vs C/C and S vs S/S) showed no significant differences both in the EPM and BDZ receptor levels. A significant decrease of was found in CA1, CA3, DG and Ce in BDZ binding sites between S/S and C offsprings raised by a stressed foster mother (C/S). However, BDZ binding sites in hippocampal regions of C/S were similar to control (C/C) except for Ce that showed a significant increase. In contrast, offsprings of control mothers raised by rats stressed during pregnancy (C/S) showed similar levels of anxiety to S/S. These results are suggesting that adult prenatally stressed rats suffer modifications in the GABA/BDZ receptors, that are associated to an anxiogenic behaviour in the adult life that can be modified by the postnatal environment. However, different mechanisms might be acting at BDZ receptors levels in the amygdala if the stress insult is inflicted postnatally as opposed to prenatally.