Stimulation of the slow calcium current in bullfrog skeletal muscle fibers by cAMP and cGMP.
Stimulation of the slow calcium current in bullfrog skeletal muscle fibers by cAMP and cGMP.
复制标题
cAMP 和 cGMP 刺激牛蛙骨骼肌纤维中的慢钙电流。
DOI：
10.1152/ajpcell.1993.265.1.c47
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
Sperelakis,N
中科院分区：
文献类型：
--
作者：
Kokate,TG;Heiny,JA;Sperelakis,N
采用电压钳技术研究了环磷酸腺苷（cAMP）和环磷酸鸟苷（cGMP）对牛蛙骨骼肌肌纤维慢钙电流（伊卡）的影响。cAMP和cGMP诱导的伊卡的振幅显着增加时，施加到纤维的切断端。这两种环核苷酸也减少了在所有膜电位的峰值电流的时间。cAMP和cGMP使电流-电压关系向更负的电位移动。cAMP和cGMP对伊卡的增强作用是相加的。8-两种核苷酸的溴类似物对伊卡具有相似的作用。β-肾上腺素能激动剂异丙肾上腺素，适用于细胞外，也产生了增加的振幅伊卡和产生的电流-电压关系的一个相移。这些结果表明，cAMP和cGMP调节牛蛙骨骼肌纤维中的钙慢通道，引起伊卡的刺激。环核苷酸对牛蛙骨骼肌中的伊卡的作用与哺乳动物心肌中的作用形成对比，在哺乳动物心肌中，相同的核苷酸对慢伊卡产生相反的作用，即，在心肌中，cAMP刺激缓慢的ICa，而cGMP抑制缓慢的伊卡。
The effects of adenosine 3',5'-cyclic monophosphate (cAMP) and guanosine 3',5'-cyclic monophosphate (cGMP) on slow calcium currents (ICa) were investigated using the Vaseline-gap voltage-clamp technique in bullfrog skeletal muscle cut fibers. Both cAMP and cGMP induced a pronounced increase in the amplitude of ICa when applied to the cut ends of fibers. Both cyclic nucleotides also decreased time to peak current at all membrane potentials. The current-voltage relationship was shifted toward more negative potentials by cAMP as well as cGMP. The potentiating effects of cAMP and cGMP on ICa were additive. 8-Bromo analogues of both nucleotides had similar effects on ICa. The beta-adrenergic agonist isoproterenol, applied extracellularly, also produced an increase in the amplitude of ICa and produced a leftward shift in the current-voltage relationship. These results suggest that both cAMP and cGMP modulate calcium slow channels in bullfrog skeletal muscle fibers, causing stimulation of the ICa. The effect of cyclic nucleotides on ICa in bullfrog skeletal muscle contrasts with that in mammalian cardiac muscle, in which the same nucleotides produce opposite effects on the slow ICa, i.e., in cardiac muscle cAMP stimulates, and cGMP inhibits, the slow ICa.