Honoré E, Dupuis B
Institut de pharmacologie moléculaire et cellulaire, centre national de la recherche scientifique, Valbonne.
Arch Mal Coeur Vaiss. 1991 Jan;84 Spec No 1:9-13.
Two phenomena may lead to an increase in intracellular calcium concentration of vascular smooth muscle cells: an increase in the permeability of the cell membrane to Ca2+ ions; liberation of Ca2+ ions from the intracellular reservoirs. The calcium channels of smooth muscle are varied. There are two types of voltage operated calcium channels: the fast (T) and the slow (L) channels. The calcium channels activated by extracellular membrane receptors are not voltage dependent. Only the L calcium channels are sensitive to dihydropyridines. The liberation of Ca2+ from the sarcoplasmic reticulum which is the intracellular reservoir of calcium can be controlled by two different mechanisms: a direct mechanism by the influx of Ca2+ into the cell through the voltage-operated channels; by the intermediary of a second intracellular messenger. High conductance calcium channels controlled by cytosolic Ca2+ and by IP2 have been demonstrated on the membrane of the sarcoplasmic reticulum. The contraction of smooth muscle may therefore be regulated directly through control of the phosphorylation of the contractile proteins by the intermediary of the systems of adenylate and guanylate cyclase.
细胞膜对Ca2+离子的通透性增加；Ca2+离子从细胞内储存库释放。平滑肌的钙通道多种多样。有两种电压门控钙通道：快速（T）通道和慢速（L）通道。由细胞外膜受体激活的钙通道不依赖电压。只有L型钙通道对二氢吡啶敏感。Ca2+从作为细胞内钙储存库的肌浆网释放可通过两种不同机制控制：一种直接机制是Ca2+通过电压门控通道流入细胞；通过第二种细胞内信使介导。在肌浆网膜上已证实存在受胞质Ca2+和IP2控制的高电导钙通道。因此，平滑肌的收缩可通过腺苷酸环化酶和鸟苷酸环化酶系统介导，直接通过控制收缩蛋白的磷酸化来调节。
