Chloride-induced contraction in a skinned fiber of toad striated muscle.
Chloride-induced contraction in a skinned fiber of toad striated muscle.
复制标题
氯化物引起蟾蜍横纹肌带皮纤维的收缩。
DOI：
10.2170/jjphysiol.27.501
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发表时间：
1977
期刊：
影响因子：
--
通讯作者：
K. Hashizume
中科院分区：
文献类型：
--
作者：
S. Matsubara;T. Sakai;K. Hashizume
用离体蟾蜍缝匠肌带皮纤维研究了氯离子引起的收缩。当K-甲烷磺酸盐在松弛溶液中被等渗地用KCl取代时，由于“去极化”诱导的SR上的Ca++释放，皮肤纤维收缩。通过用含有不同浓度Cl-的溶液灌注纤维来诱导收缩。在2 mM EGTA的存在下，当松弛溶液被含有高达20 mM Cl-的Cl-溶液替代时，Cl-诱导的收缩发展，而在0.5 mM EGTA的存在下，收缩开始于15 mM Cl-。Cl-引起的收缩的峰值张力依赖于Cl-浓度，而不服从全有或全无定律。当用1.5 mM咖啡因处理纤维时，Cl-诱导收缩的阈值显著降低。尽管以前的应用程序中的Cl-在不同浓度低于80 mM，皮肤纤维收缩突然增加Cl-浓度，和张力与Cl-浓度曲线显示几乎相同的形状，在与Cl-无溶液平衡的纤维。这表明SR膜在Cl-浓度升高引起的短暂去极化后复极化。
Cl- -induced contraction was studied in a skinned fiber dissected from toad sartorius muscle. When K-methanesulphonate in a relaxing solution was replaced isotonically with KCl, the skinned fiber contracted due to 'depolarization'-induced Ca++ release on the SR. Contraction was induced by superfusing the fiber with solutions containing different concentrations of Cl-. In the presence of 2 mM EGTA, the Cl- -induced contraction developed when the relaxing solution was replaced by a Cl- solution which contained up to 20 mM Cl-, while contraction started at 15 mM-Cl- in the presence of 0.5 mM EGTA. The peak tension of the Cl- -induced contraction depended on Cl- concentration without obeying the all-or-none law. When the fiber was treated with 1.5 mM caffeine, the threshold for the Cl- -induced contraction was significantly lowered. In spite of previous application of Cl- at different concentrations below 80 mM, the skinned fiber contracted by sudden increase in Cl- concentration, and the tension versus Cl- concentration curve revealed almost the same shape as that in a fiber equilibrated with Cl- -free solution. This suggests that the SR membrane is repolarized after transient depolarization caused by elevation of Cl- concentration.