Meddle Simone L, Bishop Valerie R, Gkoumassi Effimia, van Leeuwen Fred W, Douglas Alison J
Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, University of Edinburgh, George Square, Edinburgh, United Kingdom.
Endocrinology. 2007 Oct;148(10):5095-104. doi: 10.1210/en.2007-0615. Epub 2007 Jul 12.
Oxytocin plays a pivotal role in rat parturition, acting within the brain to facilitate its own release in the supraoptic nucleus (SON) and paraventricular nucleus, and to stimulate maternal behavior. We investigated oxytocin receptor (OTR) expression and activation perinatally. Using a (35)S-labeled riboprobe complementary to OTR mRNA, OTR expression was quantified in proestrus virgin, 21- and 22-day pregnant, parturient (90 min. from pup 1 birth), and postpartum (4-12 h from parturition) rats. Peak OTR mRNA expression was observed at parturition in the SON, brainstem regions, medial preoptic area (mPOA), bed nucleus of the stria terminalis (BnST), and olfactory bulbs, but there was no change in the paraventricular nucleus and lateral septum. OTR mRNA expression was increased on the day of expected parturition in the SON and brainstem, suggesting that oxytocin controls the pathway mediating input from uterine signals. Likewise, OTR mRNA expression was increased in the mPOA and BnST during labor/birth. In the olfactory bulbs and medial amygdala, parturition induced increased OTR mRNA expression compared with pre-parturition, reflecting their immediate response to new stimuli at birth. Postpartum OTR expression in all brain regions returned to levels observed in virgin rats. Parturition significantly increased the number of double-immunolabeled cells for Fos and OTR within the SON, brainstem, BnST, and mPOA regions compared with virgin rats. Thus, there are dynamic region-dependent changes in OTR-expressing cells at parturition. This altered OTR distribution pattern in the brain perinatally reflects the crucial role oxytocin plays in orchestrating both birth and maternal behavior.
催产素在大鼠分娩过程中起着关键作用，它在大脑中发挥作用，促进自身在视上核（SON）和室旁核的释放，并刺激母性行为。我们研究了围产期催产素受体（OTR）的表达和激活情况。使用与OTR mRNA互补的（35）S标记核糖探针，对动情前期未孕、妊娠21天和22天、分娩期（距第一只幼崽出生90分钟）和产后（分娩后4 - 12小时）的大鼠进行OTR表达定量分析。在分娩时，SON、脑干区域、内侧视前区（mPOA）、终纹床核（BnST）和嗅球中观察到OTR mRNA表达峰值，但室旁核和外侧隔没有变化。在预期分娩日，SON和脑干中的OTR mRNA表达增加，表明催产素控制着介导子宫信号输入的途径。同样，在分娩/出生期间，mPOA和BnST中的OTR mRNA表达增加。与分娩前相比，在嗅球和内侧杏仁核中，分娩诱导OTR mRNA表达增加，反映了它们在出生时对新刺激的即时反应。产后所有脑区的OTR表达恢复到未孕大鼠中观察到的水平。与未孕大鼠相比，分娩显著增加了SON、脑干、BnST和mPOA区域内Fos和OTR双免疫标记细胞的数量。因此，分娩时OTR表达细胞存在动态的区域依赖性变化。围产期大脑中这种改变的OTR分布模式反映了催产素在协调分娩和母性行为中所起的关键作用。
