Department of Physiology, Brain Health Research Centre, Centre for Neuroendocrinology, University of Otago, Dunedin, New Zealand.
Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.
J Neuroendocrinol. 2020 Jun;32(6):e12856. doi: 10.1111/jne.12856. Epub 2020 May 14.
Somato-dendritic secretion was first demonstrated over 30 years ago. However, although its existence has become widely accepted, the function of somato-dendritic secretion is still not completely understood. Hypothalamic magnocellular neurosecretory cells were among the first neuronal phenotypes in which somato-dendritic secretion was demonstrated and are among the neurones for which the functions of somato-dendritic secretion are best characterised. These neurones secrete the neuropeptides, vasopressin and oxytocin, in an orthograde manner from their axons in the posterior pituitary gland into the blood circulation to regulate body fluid balance and reproductive physiology. Retrograde somato-dendritic secretion of vasopressin and oxytocin modulates the activity of the neurones from which they are secreted, as well as the activity of neighbouring populations of neurones, to provide intra- and inter-population signals that coordinate the endocrine and autonomic responses for the control of peripheral physiology. Somato-dendritic vasopressin and oxytocin have also been proposed to act as hormone-like signals in the brain. There is some evidence that somato-dendritic secretion from magnocellular neurosecretory cells modulates the activity of neurones beyond their local environment where there are no vasopressin- or oxytocin-containing axons but, to date, there is no conclusive evidence for, or against, hormone-like signalling throughout the brain, although it is difficult to imagine that the levels of vasopressin found throughout the brain could be underpinned by release from relatively sparse axon terminal fields. The generation of data to resolve this issue remains a priority for the field.
躯体-树突分泌在 30 多年前首次被证实。然而，尽管其存在已被广泛接受，但躯体-树突分泌的功能仍未被完全理解。下丘脑大细胞神经分泌细胞是最早被证实存在躯体-树突分泌的神经元表型之一，也是躯体-树突分泌功能研究得最好的神经元之一。这些神经元以顺行的方式从前垂体的轴突中分泌神经肽加压素和催产素到血液循环中，以调节体液平衡和生殖生理学。逆行的躯体-树突分泌加压素和催产素调节它们分泌的神经元以及邻近神经元群体的活性，以提供内部分群和外部分群信号，协调内分泌和自主反应，以控制外周生理学。躯体-树突分泌的加压素和催产素也被认为在大脑中充当激素样信号。有一些证据表明，大细胞神经分泌细胞的躯体-树突分泌调节了其局部环境之外的神经元的活性，尽管在大脑中没有含有加压素或催产素的轴突，但到目前为止，还没有确凿的证据支持或反对整个大脑中的激素样信号，尽管很难想象大脑中发现的加压素水平可以通过相对稀疏的轴突末梢释放来支撑。生成数据以解决这个问题仍然是该领域的一个优先事项。
