Augustine Rachael A, Seymour Alexander J, Campbell Rebecca E, Grattan David R, Brown Colin H
Department of Physiology Brain Health Research Centre, Centre for Neuroendocrinology.
Department of Anatomy, University of Otago, Dunedin, New Zealand.
J Neuroendocrinol. 2018 Jan 11. doi: 10.1111/jne.12569.
Oxytocin is required for normal birth and lactation. Oxytocin is synthesised by hypothalamic supraoptic and paraventricular nuclei neurons and is released into the circulation from the posterior pituitary gland. Under basal conditions, circulating oxytocin levels are relatively constant but during birth and lactation, pulsatile oxytocin release triggers rhythmic contraction of the uterus during birth and milk ejection during suckling. Oxytocin levels are principally determined by the pattern of action potential firing that is, in turn, determined by the interplay between the intrinsic properties of the oxytocin neurons, regulation of their excitability by surrounding glia as well as by synaptic drive from their afferent inputs. During birth and suckling, oxytocin neurons fire high-frequency bursts of action potentials that are coordinated across the population of neurons and these bursts underpin the pulsatile secretion of oxytocin required for normal birth and lactation. Neuroglial regulation of oxytocin neurons changes during pregnancy to favour burst firing. However, these changes still require afferent input activity to drive activity. While it has long been known that noradrenergic inputs to oxytocin neurons are activated during birth and lactation, the involvement of other afferent inputs is less clear. Here, we provide a brief overview of the current understanding of the mechanisms that regulate oxytocin neuron activity during pregnancy and lactation, and focus on recent evidence from our laboratory identifying an input that increases kisspeptin production to excite oxytocin neurons in late pregnancy. This article is protected by copyright. All rights reserved.
正常分娩和泌乳需要催产素。催产素由下丘脑视上核和室旁核神经元合成，并从垂体后叶释放进入循环系统。在基础状态下，循环中的催产素水平相对恒定，但在分娩和泌乳期间，脉冲式催产素释放会在分娩时触发子宫的节律性收缩，并在哺乳时引发喷乳。催产素水平主要由动作电位发放模式决定，而动作电位发放模式又反过来由催产素神经元的内在特性、周围神经胶质细胞对其兴奋性的调节以及来自其传入输入的突触驱动之间的相互作用所决定。在分娩和哺乳期间，催产素神经元会发放高频动作电位爆发，这些爆发在神经元群体中是协调一致的，并且这些爆发是正常分娩和泌乳所需的催产素脉冲式分泌的基础。在怀孕期间，神经胶质细胞对催产素神经元的调节会发生变化，以利于爆发式发放。然而，这些变化仍然需要传入输入活动来驱动其活动。虽然长期以来人们都知道在分娩和泌乳期间，去甲肾上腺素能输入到催产素神经元会被激活，但其他传入输入的参与情况尚不清楚。在这里，我们简要概述了目前对怀孕期间和泌乳期间调节催产素神经元活动机制的理解，并重点关注我们实验室最近的证据，该证据确定了一种在妊娠晚期增加 kisspeptin 产生以兴奋催产素神经元的输入。本文受版权保护。保留所有权利。
