Yu J, Bose R
Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, Canada.
Gastroenterology. 1991 May;100(5 Pt 1):1448-60.
The molecular and biophysical characterization of Ca2+ channels in smooth muscle has lagged behind that in cardiac and skeletal muscles. This is caused by the difficulties in isolating viable cells and applying electrophysiological techniques to smooth muscle cells. The heterogeneity of smooth muscle cells from different organs also adds to the complexity. In spite of these problems there has been an increasing number of reports on Ca2+ channels in smooth muscle. This review provides an overview of this area. As in skeletal muscles, L (long-acting) and T (transient) voltage-dependent Ca2+ channels are found in smooth muscle; the former is better characterized. L channel is regulated by voltage, Ca2+, cyclic nucleotides, and protein kinase C. Ca2+ also influxes through receptor-operated channels that are voltage insensitive. The receptor-operated and T channels are insensitive to dihydropyridine. Clinically, Ca2+ blockers are extensively used for diseases of the cardiovascular system, with more limited use in the gastrointestinal tract. Further understanding of the properties of Ca2+ channels could lead to development of selective Ca2+ channel blockers for the gastrointestinal tract.
平滑肌中钙通道的分子和生物物理特性研究落后于心肌和骨骼肌。这是由于分离活细胞以及将电生理技术应用于平滑肌细胞存在困难。不同器官的平滑肌细胞异质性也增加了复杂性。尽管存在这些问题，但关于平滑肌中钙通道的报道仍越来越多。本综述对该领域进行了概述。与骨骼肌一样，平滑肌中也发现了L（长效）型和T（瞬时）型电压依赖性钙通道；前者的特征更为明确。L型通道受电压、钙离子、环核苷酸和蛋白激酶C的调节。钙离子也通过对电压不敏感的受体操纵通道内流。受体操纵通道和T型通道对二氢吡啶不敏感。临床上，钙通道阻滞剂广泛用于心血管系统疾病，在胃肠道的应用则较为有限。对钙通道特性的进一步了解可能会促使开发出用于胃肠道的选择性钙通道阻滞剂。
