Sex Differences in the Diurnal Variation of Dopamine Signaling

Abstract

Circadian rhythms regulate mammalian behavior and largely affect dopaminergic pathways. This results in rhythmic fluctuations in dopamine (DA) activity. These trends have been widely studied in male subjects and play a role in psychiatric illnesses such as anxiety and substance use disorder. Understanding how diurnal variations affect such illnesses is vital to creating treatment, however, sex differences within these trends have not been investigated. Stimulating DA release in the nucleus accumbens (NAc) core, a DA-rich area of the brain, using FSCV, it was seen that diurnal variation of DA release is consistent between males and females. Applying DhβE, a known nicotinic acetylcholine receptor antagonist, shows that cholinergic interneurons (CIN), known to mediate diurnal patterns of DA release in males seem to have little effect on this pattern in females. This seems to indicate a fundamental difference in the mechanism for the diurnal variation of DA signaling between the sexes.