Brauer M Mónica
Laboratory of Cell Biology, Instituto de Investigaciones Biológicas Clemente Estable, Avenida Italia 3318, Montevideo 11600, Uruguay.
Auton Neurosci. 2008 Jun;140(1-2):1-16. doi: 10.1016/j.autneu.2008.02.002. Epub 2008 Apr 9.
Dynamic responses of uterine sympathetic nerves to changes in the circulating levels of sex hormones represent one of the most remarkable examples of physiological plasticity in the adult autonomic nervous system. The density of uterine sympathetic nerves is markedly and irreversibly reduced following puberty, and shows phases of degeneration and regeneration during the natural oestrous cycle. Even more remarkable, uterine sympathetic nerves degenerate during normal pregnancy and regenerate following delivery. Plasticity in uterine sympathetic nerves was initially interpreted as a selective effect of sex hormones on the system of paracervical short adrenergic neurons supplying the uterus. In the last decade, the alternative explanation that sex hormones might alter the ability of the uterine tissue to support its innervation began to be explored and current evidence indicates that oestrogen and pregnancy elicit changes in the neuritogenic properties of the target uterine tissue. In addition, there are indications that sex hormones may also affect the receptivity of uterine-related sympathetic neurons to target-derived signals. Although the nature of these signals is still fragmentary, there is evidence for the contribution of a range of molecules, including neurotrophins, pro-neurotrophins and chemorepulsive signals of the semaphorin family. This review summarizes some general features of plasticity in uterine sympathetic nerves and highlights recent investigations of the cellular and molecular mechanisms underlying this dramatic model of natural plasticity.
子宫交感神经对循环中性激素水平变化的动态反应是成年自主神经系统中生理可塑性最显著的例子之一。青春期后，子宫交感神经的密度显著且不可逆地降低，并在自然发情周期中呈现退化和再生阶段。更值得注意的是，子宫交感神经在正常妊娠期间退化，并在分娩后再生。子宫交感神经的可塑性最初被解释为性激素对供应子宫的子宫颈旁短肾上腺素能神经元系统的选择性作用。在过去十年中，开始探索性激素可能改变子宫组织支持其神经支配能力的另一种解释，目前的证据表明雌激素和妊娠会引起靶子宫组织神经发生特性的变化。此外，有迹象表明性激素也可能影响与子宫相关的交感神经元对靶源性信号的反应性。尽管这些信号的性质仍然不完整，但有证据表明一系列分子发挥了作用，包括神经营养因子、前神经营养因子和信号素家族的化学排斥信号。本综述总结了子宫交感神经可塑性的一些一般特征，并重点介绍了对这种自然可塑性显著模型背后的细胞和分子机制的最新研究。
