Department of Integrative Physiology, Gunma University Graduate School of Medicine, Maebashi, Japan.
Department of Nutrition, Takasaki University of Health and Welfare, Takasaki, Japan.
Dev Psychobiol. 2022 Mar;64(3):e22264. doi: 10.1002/dev.22264.
Elucidating the mechanisms underlying nurturing and neglect behaviors is meaningful but challenging. Recently, we found that CIN85-deficient mice had reduced pituitary hormone prolactin secretion during late pregnancy, and their pups later showed an inhibited nurturing behavior. To examine whether this phenomenon could be reproduced in normal mice and not just CIN85-deficient mice, we investigated the nurturing behavior of offspring born to mothers whose blood prolactin levels had been reduced by bromocriptine administration during late pregnancy. First, to determine when bromocriptine treatment should be started, we investigated the detailed changes in blood prolactin levels in late pregnancy in mice, resulting in the identification of the prepartum prolactin surge. Furthermore, prolactin receptors in the fetal hypothalamus were expressed to the same extent as in the adult hypothalamus. Treatment with bromocriptine decreased the plasma concentrations of prolactin to the basal range throughout late pregnancy. However, against expectations, the proportion of the resultant pups exhibiting nurturing behaviors as adults was as high as that in the mice without bromocriptine treatment. In conclusion, the elimination of prolactin secretion during late pregnancy alone does not induce neglect-like behavior in offspring, suggesting that CIN85-deficient mice appear to involve another factor due to CIN85 deficiency besides prolactin deficiency.
阐明养育和忽视行为的机制具有重要意义，但具有挑战性。最近，我们发现 CIN85 缺陷小鼠在妊娠晚期催乳素分泌减少，其后代随后表现出抑制养育行为。为了检查这种现象是否可以在正常小鼠中重现，而不仅仅是在 CIN85 缺陷小鼠中重现，我们研究了母亲在妊娠晚期用溴隐亭处理降低血液催乳素水平后所生后代的养育行为。首先，为了确定何时开始溴隐亭治疗，我们研究了妊娠晚期小鼠血液催乳素水平的详细变化，从而确定了产前催乳素激增。此外，胎儿下丘脑中的催乳素受体表达与成年下丘脑中的催乳素受体表达相同。溴隐亭治疗使整个妊娠晚期的血浆催乳素浓度降低到基础范围。然而，出乎意料的是，表现出养育行为的幼鼠比例与未用溴隐亭处理的小鼠一样高。总之，妊娠晚期催乳素分泌的消除本身并不会诱导后代出现类似忽视的行为，这表明 CIN85 缺陷小鼠似乎除了催乳素缺乏之外，还由于 CIN85 缺陷而涉及另一个因素。
