Sex differences in the septo-hippocampal cholinergic system in rats: Behavioral consequences

Abstract

The hippocampus is processing temporal and spatial information in particular contexts or episodes. Using freely moving rats, we monitored extracellular levels of acetylcholine (ACh), a critical neurotransmitter activating hippocampal circuits. We found that the ACh release in the dorsal hippocampus increases during the period of learning or exploration, exhibiting a sex-specific 24-h release profile. Moreover, neonatal increase in circulating androgen not only androgenizes behavioral and hormonal features, but also produces male-type ACh release profile after the development. The results suggest neonatal sexual differentiation of septohippocampal cholinergic system. Environmental conditions (such as stress, housing or food) of animals further affected the ACh release. Although recent advances of neuroscience successfully revealed molecular/ cellular mechanism of learning and memory, most research were performed using The hippocampus is processing temporal and spatial information in particular contexts or episodes. Using freely moving rats, we monitored extracellular levels of acetylcholine (ACh), a critical neurotransmitter activating hippocampal circuits. We found that the ACh release in the dorsal hippocampus increases during the period of learning or exploration, exhibiting a sex-specific 24-h release profile. Moreover, neonatal increase in circulating androgen not only androgenizes behavioral and hormonal features, but also produces male-type ACh release profile after the development. The results suggest neonatal sexual differentiation of septohippocampal cholinergic system. Environmental conditions (such as stress, housing or food) of animals further affected the ACh release. Although recent advances of neuroscience successfully revealed molecular/ cellular mechanism of learning and memory, most research were performed using male animals at specific time period. Sex-specific or time-dependent hippocampal functions are still largely unknown. © Springer-Verlag Berlin Heidelberg 2011.