Korbmacher C, Helbig H, Coroneo M, Erickson-Lamy K A, Stiemer B, Tamm E, Lütjen-Drecoll E, Wiederholt M
Institut für Klinische Physiologie, Freie Universität Berlin, FRG.
Invest Ophthalmol Vis Sci. 1990 Nov;31(11):2420-30.
A smooth muscle cell line (H7CM) was established from the ciliary muscle of a 1-day-old human infant. The cultured cells had a normal female karyotype (46 XX) and could be maintained in cell culture for at least 11 generations. A common feature of confluent cultures was the presence of abundant bundles of 6-7 nm microfilaments associated with dense bodies. Both the ultrastructural appearance and the presence of smooth muscle-specific alpha-isoactin (also present in the human ciliary muscle in situ) support the smooth muscle origin of the H7CM cell line. Continuous membrane voltage (Vm) recordings were obtained in confluent monolayers of H7CM cells using glass microelectrodes. Resting Vm in 105 impalements averaged -66.2 +/- 0.7 mV (mean +/- standard error of the mean). In this system, rapid membrane transients induced by changing of the superfusing test solutions were detectable. Relative K+ conductance was characterized, and the contribution of electrogenic sodium/potassium adenosine triphosphatase to Vm was investigated. Under control conditions, H7CM cells were electrically quiescent. However, action potentials could be induced by application of 10 mM barium. Barium-induced action potentials were not abolished by removal of extracellular Na+ nor were they inhibited by the presence of tetrodotoxin. However, they were blocked by verapamil, fulfilling criteria believed to be typical for smooth muscle cells. Acetylcholine, carbachol, and to a lesser extent pilocarpine induced a reversible Vm depolarization. The effect of acetylcholine was blocked by atropine, implying muscarinic receptor involvement in the Vm response. Collectively, these findings show the potential usefulness of cultured ciliary muscle cells in understanding further the cellular mechanisms underlying drug-induced contraction of the human ciliary muscle.
从一名1日龄人类婴儿的睫状肌中建立了一种平滑肌细胞系（H7CM）。培养的细胞具有正常的女性核型（46 XX），并且可以在细胞培养中维持至少11代。汇合培养的一个共同特征是存在与致密体相关的大量6 - 7纳米微丝束。超微结构外观和平滑肌特异性α - 同工肌动蛋白的存在（也存在于原位的人类睫状肌中）都支持H7CM细胞系的平滑肌起源。使用玻璃微电极在H7CM细胞的汇合单层中获得连续的膜电压（Vm）记录。105次刺入的静息Vm平均为 - 66.2 +/- 0.7 mV（平均值 +/- 平均值的标准误差）。在这个系统中，由更换灌注测试溶液诱导的快速膜瞬变是可检测到的。对相对钾电导进行了表征，并研究了电生钠/钾三磷酸腺苷酶对Vm的贡献。在对照条件下，H7CM细胞电静息。然而，施加10 mM钡可诱导动作电位。钡诱导的动作电位不会因去除细胞外钠而消除，也不会被河豚毒素抑制。然而，它们被维拉帕米阻断，符合被认为是平滑肌细胞典型的标准。乙酰胆碱、卡巴胆碱以及程度较轻的毛果芸香碱诱导可逆的Vm去极化。乙酰胆碱的作用被阿托品阻断，这意味着毒蕈碱受体参与了Vm反应。总的来说，这些发现表明培养的睫状肌细胞在进一步理解人类睫状肌药物诱导收缩的细胞机制方面具有潜在的用途。
