Nucleus accumbens serotonin 1A receptor expression is altered by female reproduction and regulates postpartum affective and caregiving behaviors.

This article focuses on the role of serotonin 1A (5-HT1A) receptors in the nucleus accumbens shell (NAcSh) in regulating postpartum affective and maternal caregiving behaviors in rats. The study found that 5-HT1A receptor mRNA and binding in the NAcSh significantly increase around parturition, and that site-specific knockdown of these receptors impairs maternal motivation, increases anxiety-like behaviors, and reduces dopamine-related tyrosine hydroxylase expression in the NAcSh. Additionally, repeated pregnancy stress altered the normal pattern of 5-HT1A receptor binding in the NAcSh, disrupted caregiving behaviors, and induced affective deficits such as anhedonia and increased immobility in a forced swim test. These findings suggest that 5-HT1A receptor signaling in the NAcSh is critical for the behavioral adaptations of motherhood and may represent a target for pharmacotherapies addressing postpartum affective disorders.