Moderate prenatal alcohol exposure reduces parvalbumin expressing GABAergic interneurons in the dorsal hippocampus of adult male and female rat offspring

Abstract

Prenatal alcohol exposure (PAE) negatively impacts hippocampal development and impairs hippocampal-sensitive learning and memory. However, hippocampal neural adaptations in response to moderate PAE are not completely understood. To explore the effects of moderate PAE on GABAergic interneuron expression, this study used a rat model of moderate PAE to examine the effects of PAE on parvalbumin (PARV)-positive cells in fields CA1, CA3 and the dentate gyrus (DG) of the dorsal hippocampus (dHC). Long-Evans dams were given daily access to 5 % (vol/vol) ethanol or saccharine (SAC) control solutions throughout the course of gestation. Offspring were divided into four separate groups: PAE (n = 7) or SAC (n = 7) males, or PAE (n = 8) or SAC (n = 8) females. All rats were aged to adulthood and, following testing in the Morris water task, their brains were analyzed for the expression of the GABAergic neuronal marker PARV. We report a main effect of PAE on GABAergic expression, with significant reductions in PARV-positive cells in area CA3 for males and the DG for females. There was also a trend for a reduction in PARV expressing neurons in fields CA1 and CA3 in females. The results are discussed in relation to hippocampal GABAergic interneuron function, PAE and behavior.

Keywords: Fetal alcohol spectrum disorder; Interneuron; Memory; PAE; Prenatal alcohol exposure.