Role of Ca2+ channel in development of tension in heart muscle.
Role of Ca2+ channel in development of tension in heart muscle.
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DOI：
10.1016/s0022-2828(87)80360-7
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发表时间：
1987-06
影响因子：
5
通讯作者：
M. Morad;L. Cleemann
中科院分区：
文献类型：
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作者：
M. Morad;L. Cleemann
在哺乳动物和两栖动物的心脏中，Ca2+ 通过电压门控 Ca2+ 通道进入心肌细胞。 Ca2+ 通道在从光不稳定的 Ca2+ 拮抗剂中逐步恢复后，通过检查电压钳位心肌条中张力和 ICa 的重建来探讨 Ca2+ 通道在运输激活剂 Ca2+ 中的作用。比较Ca2+通道阻滞剂光失活后青蛙和哺乳动物心脏张力重建的动力学表明，青蛙心脏张力在一次心跳中完全重建，而哺乳动物心脏张力完全重建需要5至7次。使用 Antipyrylazo III 进行的 Ca2+ 消耗研究表明，动作电位期间细胞外 Ca2+ 消耗主要通过 Ca2+ 通道发生。在青蛙心脏中，单次心跳期间从细胞外空间输送足够的 Ca2+ 来激活张力。在哺乳动物心脏中，ICa 触发内部储备的释放，只有在完全加载时才会引起张力的充分发展。ICa 还参与细胞内 Ca2+ 池的加载。在哺乳动物肌细胞中已鉴定出两种类型的 Ca2+ 通道。低阈值快速失活的 Ca2+ 通道似乎参与了 Ca2+ 的触发释放，而高阈值（传统 Ca2+ 通道）似乎主要参与了内部 Ca2+ 池的重新加载。
In mammalian and amphibian hearts Ca2+enters the myocardial cells via voltage-gated Ca2+channels. The role of Ca2+channels in transporting the activator Ca2+was probed by examining the redevelopment of tension andICain voltage-clamped myocardial strips after step recovery of Ca2+channel from photolabile Ca2+antagonist. Comparison of the kinetics of redevelopment of tension in the frog and mammalian heart following the photoinactivation of Ca2+channel blockers showed that in the frog heart tension redevelops fully in one beat, while 5 to 7 beats were required for full redevelopment of tension in the mammalian heart. Ca2+depletion studies using Antipyrylazo III showed that extracellular Ca2+depletion during the action potential occurs primarily via the Ca2+channel. In the frog heart sufficient Ca2+is transported from the extracellular space during a single beat to activate tension. In the mammalian heartICatriggers the release of internal stores, which when only fully loaded caused full development of tension.ICaalso was involved in loading the intracellular Ca2+pools. Two types of Ca2+channels have been identified in the mammalian myocytes. The low-threshold rapidly inactivating Ca2+channels appear to be involved in trigger release of Ca2+, while the high threshold (conventional Ca2+channels) seem to be involved primarily in reloading of internal Ca2+pools.