Garella Rachele, Squecco Roberta, Baccari Maria Caterina
Department of Experimental and Clinical Medicine, Section of Physiology, University of Florence, Florence. Italy.
Department of Experimental and Clinical Medicine, Section of Physiology, University of Florence, Viale G.B. Morgagni 63, 50134 Florence. Italy.
Curr Protein Pept Sci. 2017;18(12):1254-1262. doi: 10.2174/1389203718666170612104719.
The peptide hormone relaxin (RLX), in addition to its effects on reproduction, has been reported to influence gastrointestinal motility. Interestingly, the digestive tract has been shown to express RLX receptors and the hormone appears to exert site-specific effects acting at the neural or at the smooth muscle level, mainly by a nitric oxide (NO)-mediated mechanism. NO, released by the enteric nerves and/or smooth muscle cells, is one of the main mediators of gastrointestinal relaxation. In fact, in murine in vitro preparations, RLX depresses organ motility acting at the neural level in the stomach and at the muscular level in the small intestine; conversely, in the colon, this hormone paradoxically increases contractility operating at both neural and muscle levels. These effects are ascribable to the ability of RLX to selectively regulate the expression of the different nitric oxide synthase (NOS) isoforms in the different gastrointestinal tracts. Furthermore, recent electrophysiological experiments have shown that RLX can directly affect the biophysical properties of ileal and colonic smooth muscle cells. This mini-review is intended to offer an update on the site-related actions of RLX on gastrointestinal tract motility in relation with its site-specific effects on NOS isoforms expression. Based on these properties, RLX might be considered a potential therapeutic approach to gastrointestinal motor dysfunctions related to an altered NO production.
肽类激素松弛素（RLX），除了对生殖有影响外，据报道还会影响胃肠蠕动。有趣的是，消化道已被证明可表达RLX受体，并且该激素似乎通过一氧化氮（NO）介导的机制在神经或平滑肌水平发挥位点特异性作用。由肠神经和/或平滑肌细胞释放的NO是胃肠舒张的主要介质之一。事实上，在小鼠体外实验中，RLX在胃的神经水平和小肠的肌肉水平发挥作用，从而抑制器官蠕动；相反，在结肠中，这种激素在神经和肌肉水平发挥作用，反常地增加收缩性。这些作用归因于RLX选择性调节不同胃肠道中不同一氧化氮合酶（NOS）同工型表达的能力。此外，最近的电生理实验表明，RLX可直接影响回肠和结肠平滑肌细胞的生物物理特性。这篇小型综述旨在就RLX对胃肠道蠕动的位点相关作用及其对NOS同工型表达的位点特异性影响提供最新信息。基于这些特性，RLX可能被认为是一种针对与NO生成改变相关的胃肠运动功能障碍的潜在治疗方法。
