Korbmacher C, Helbig H, Haller H, Erickson-Lamy K A, Wiederholt M
Institut für Klinische Physiologie, Freie Universität Berlin, Klinikum Steglitz, FRG.
Biochem Biophys Res Commun. 1989 Nov 15;164(3):1031-9. doi: 10.1016/0006-291x(89)91773-7.
The ciliary muscle which is involved in accommodation and regulation of aqueous humour outflow resistance resembles smooth muscle in other parts of the body. In the present investigation we used an established primary cell line (H7CM) to study the effects of endothelin, a novel vasoconstrictor peptide, on membrane voltage (V) and intracellular calcium in cultured human ciliary muscle cells. Membrane voltage was measured in confluent monolayers of H7CM cells using conventional microelectrodes. Intracellular calcium concentration [( Ca]i) was measured in single H7CM cells using the fluorescent calcium indicator fura-2. Under resting conditions V averaged -66.9 +/- 0.7 mV (mean +/- SEM, n = 125). Endothelin (10(-10)-10(-6)M) induced a dose-dependent reversible membrane voltage depolarization and a dose-dependent rise in [Ca]i. The initial calcium peak was followed by a recovery phase during which oscillations of [Ca]i occurred. The initial calcium peak was not dependent on the presence of extracellular calcium and was not abolished in the presence of the calcium antagonist verapamil (10(-4)M). Thus it is probably mediated by a release of calcium from intracellular reservoirs. We conclude that cultured human ciliary muscle cells express a functional endothelin receptor.
参与调节和房水流出阻力调节的睫状肌类似于身体其他部位的平滑肌。在本研究中，我们使用已建立的原代细胞系（H7CM）来研究内皮素（一种新型血管收缩肽）对培养的人睫状肌细胞膜电压（V）和细胞内钙的影响。使用传统微电极在H7CM细胞的汇合单层中测量膜电压。使用荧光钙指示剂fura-2在单个H7CM细胞中测量细胞内钙浓度[（Ca）i]。在静息条件下，V平均为-66.9 +/- 0.7 mV（平均值+/-标准误，n = 125）。内皮素（10（-10）-10（-6）M）诱导剂量依赖性可逆膜电压去极化和[Ca]i的剂量依赖性升高。最初的钙峰之后是一个恢复期，在此期间[Ca]i发生振荡。最初的钙峰不依赖于细胞外钙的存在，并且在钙拮抗剂维拉帕米（10（-4）M）存在下也不会消失。因此，它可能是由细胞内储存库释放钙介导的。我们得出结论，培养的人睫状肌细胞表达功能性内皮素受体。
