Department of Gastroenterology, Renmin Hospital of Wuhan University, 430060 Wuhan, Hubei Province, China.
Department of Gastroenterology, Shanghai General Hospital, Shanghai Jiao Tong University, 200080 Shanghai, China.
Eur J Pharmacol. 2018 Jan 5;818:356-363. doi: 10.1016/j.ejphar.2017.11.002. Epub 2017 Nov 9.
Hydrogen sulfide (HS) can exert different effects on the gastrointestinal tract by modulating ion channels. Previously, we found that HS donor sodium hydrosulfide (NaHS) regulates colonic motility through L-type calcium channels, but the molecular mechanism remains unknown. The present study was designed to investigate possible mechanisms underlying the modulation of L-type calcium channels by NaHS in rat colonic smooth muscle cells. L-type calcium currents in colonic smooth muscle cells were recorded using the whole-cell patch-clamp technique. Spontaneous contractions of mid-colonic smooth muscle strips were measured in an organ bath system and a biological signal acquisition system. NaHS evoked a significant rightward shift in the steady-state activation curve of L-type calcium channels, changed the shape of the current-voltage (I-V) curve, and decreased the peak current density at 0mV, although it significantly increased with higher stimulatory voltage. The sulfhydryl-modifying reagent DL-dithiothreitol (DTT) enhanced the effects of NaHS on L-type calcium channels, while diamide (DM) and reduced L-glutathione (GSH) alleviated the effects of NaHS. Additionally, NaHS inhibited the spontaneous high-amplitude contractions of both longitudinal and circular smooth muscle strips in a dose-dependent manner. The inhibitory effects were reversible. DTT and GSH enhanced the effects of NaHS, while DM attenuated the effects of NaHS. In conclusion, NaHS modulates L-type calcium channels in rat colonic smooth muscle cells and regulates the contractile activity of colonic smooth muscle, potentially by modifying the free sulfhydryl groups of L-type calcium channels.
硫化氢 (HS) 可以通过调节离子通道对胃肠道产生不同的影响。先前，我们发现 HS 供体硫氢化钠 (NaHS) 通过 L 型钙通道调节结肠蠕动，但分子机制尚不清楚。本研究旨在探讨 NaHS 调节大鼠结肠平滑肌细胞中 L 型钙通道的可能机制。使用全细胞膜片钳技术记录结肠平滑肌细胞中的 L 型钙电流。在器官浴系统和生物信号采集系统中测量中结肠平滑肌条的自发性收缩。NaHS 引起 L 型钙通道稳态激活曲线明显右移，改变电流-电压 (I-V) 曲线的形状，并降低 0mV 时的峰值电流密度，尽管它随着刺激电压的升高而显著增加。巯基修饰试剂 DL-二硫苏糖醇 (DTT) 增强了 NaHS 对 L 型钙通道的作用，而二酰胺 (DM) 和还原型 L-谷胱甘肽 (GSH) 减轻了 NaHS 的作用。此外，NaHS 以剂量依赖的方式抑制纵向和环形平滑肌条的自发性高振幅收缩。抑制作用是可逆的。DTT 和 GSH 增强了 NaHS 的作用，而 DM 减弱了 NaHS 的作用。总之，NaHS 调节大鼠结肠平滑肌细胞中的 L 型钙通道，并调节结肠平滑肌的收缩活动，可能通过修饰 L 型钙通道的游离巯基基团。
