The Dependence of Unloaded Shortening Velocity on Ca++, Calmodulin, and Duration of Contraction in “Chemically Skinned” Smooth Muscle
The Dependence of Unloaded Shortening Velocity on Ca++, Calmodulin, and Duration of Contraction in “Chemically Skinned” Smooth Muscle
复制标题
“化学剥皮”平滑肌中无负荷缩短速度对 Ca、钙调蛋白和收缩持续时间的依赖性
作者：
R. Paul;G. Doerman;C. Zeugner;J. C. Riiegg
在化学剥皮的豚鼠结肠带和猪颈动脉上研究了无负荷缩短速度，这是一个与跨桥循环速率相关的力学参数。通过Edman描述的技术测量缩短速度，由此将大长度的步骤快速施加于肌肉上，并且从等长肌电图确定在无负荷条件下的时间。以这种方式确定的缩短速度与活的和剥皮的结肠带的Hill力-速度关系报告的Vmax相似，并且在颈动脉的情况下，至少与活的肌肉报告的一样大。两种制剂的缩短速度行为在定性上相似。缩短速度强烈依赖于温度，Q10约为3.6。缩短速度被认为是依赖于Ca++和钙调素浓度。与等长收缩力对Ca++-钙调素的依赖性不同，在等长收缩力最大化的条件下，加入Ca++和/或钙调素可进一步提高缩短速度。与ATP-7S孵育，这可能是最大化的肌球蛋白的磷酸化，没有增加缩短速度超过在单独的Ca++-钙调蛋白的存在下获得的最大值。高Ca ~（++）溶液作用后，短缩速度的发展先于等长收缩力的发展。稳态值倾向于略低于最大缩短速度，观察到的最大差异小于1.5倍。因此，虽然等长力和缩短速度都依赖于皮肤平滑肌中的Ca++-钙调蛋白浓度，但依赖性并不相同，在时间发育和浓度方面有所不同。这些差异可能是在活平滑肌中观察到的维持等长力的速度下降的基础。
Unloaded shortening velocity, a mechanical parameter associated with the rate of cross-bridge cycling, was investigated in chemically skinned guinea pig taenia coli and hog carotid artery. Shortening velocity was measured by the technique described by Edman, whereby large length steps are rapidly imposed on the muscle and the time under unloaded conditions is determined from the isometric myograms. Shortening velocity determined in this manner was similar to Vmax from the Hill force-velocity relations reported for both living and skinned taenia coli, and, in the case of carotid artery, was at least as large as that reported for living muscle. The behavior of shortening velocity was qualitatively similar for both preparations. Shortening velocity was strongly temperature dependent, with a Q]o of approximately 3.6. Shortening velocity was found to be dependent on both the Ca++ and calmodulin concentration. In contrast to the dependence of isometric force on Ca++-calmodulin, shortening velocity could be increased further by the addition of Ca++ and/or calmodulin under conditions when isometric force was maximized. Incubation with ATP-7S, which presumably maximizes the phosphorylahon of myosin, did not increase shortening velocity beyond the maximum value obtained in the presence of Ca++- calmodulin alone. The development of shortening velocity after exposure to high Ca++ solution was found to precede that of isometric force. The steady state value tended to be slightly lower than the maximum shortening velocity, the largest difference observed being less than 1.5-fold. Thus, whereas both isometric force and shortening velocity are dependent on the Ca++-calmodulin concentration in skinned smooth muscle, the dependencies are not identical, differing with respect to temporal development and concentration. These differences may underlie the decline in velocity with maintained isometric force observed in living smooth muscle.
平滑肌肌球蛋白的磷酸化：肌球蛋白头之间协同作用的证据。
DOI：
10.1126/science.6455737
发表时间：
1981
期刊：
Science (New York, N.Y.)
影响因子：
--
作者：
Persechini,A;Hartshorne,DJ
通讯作者：
Hartshorne,DJ
气管平滑肌肌球蛋白轻链和磷酸化酶磷酸化的调节。
DOI：
--
发表时间：
1982
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Silver,PJ;Stull,JT
通讯作者：
Stull,JT