Raffa R B, Bianchi C P, Narayan S R
Department of Pharmacology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania.
J Pharmacol Exp Ther. 1987 Oct;243(1):200-4.
The present study examined the effects of three heavy metals on the acetylcholine (ACh) contracture and Ca++ kinetics of the anterior byssus retractor muscle of Mytilus edulis. An isolated tissue bioassay using anterior byssus retractor muscle was prepared according to standard procedures and the isometric tension produced in response to ACh was measured. Ten millimolar Ni++, Co++ or Cd++ reduced the maximum contracture response to ACh in zero-Ca medium in a time-dependent manner. The inhibition was reversed upon restoration of medium containing 10 mM Ca++. The loss (and re-establishment) of contracture response to ACh corresponded to the influx (and efflux) of the heavy metal ions opposite to the direction of Ca++ flow. These results are consistent with the concept that the loss of the ACh contracture response is attributable to the displacement of tissue Ca++ from release sites by heavy metals.
本研究考察了三种重金属对紫贻贝前足丝牵缩肌乙酰胆碱（ACh）挛缩及钙离子动力学的影响。按照标准程序制备了使用前足丝牵缩肌的离体组织生物测定法，并测量了对ACh产生的等长张力。10毫摩尔的镍离子、钴离子或镉离子以时间依赖性方式降低了零钙培养基中对ACh的最大挛缩反应。当恢复含有10毫摩尔钙离子的培养基时，抑制作用被逆转。对ACh挛缩反应的丧失（和重新建立）与重金属离子与钙离子流动方向相反的流入（和流出）相对应。这些结果与以下概念一致，即ACh挛缩反应的丧失是由于重金属将组织中的钙离子从释放位点置换所致。
