Wang Z, Bianchi C P, Narayan S R
J Pharmacol Exp Ther. 1984 Jun;229(3):696-701.
Replacement of calcium in artificial sea water (ASW) by nickel causes a loss of calcium at a single exponential rate (tau = 23.2 min) and the loss of contracture response to acetylcholine (ACh) in the anterior byssus retractor muscle of Mytilus edulis L. The ACh contracture response is lost at two rates; 93% of the ACh contracture response is lost rapidly (tau = 7.43 min) and the remaining 7% of ACh contracture response is lost slowly (tau = 66.6 min). The rapid phase of loss of ACh contracture corresponds to the rapid exponential uptake of nickel (tau = 6.5 min). The loss of ACh contracture response is attributed to the displacement of calcium from membrane release sites by nickel. In O-Ca-Mg ASW, the ACh contracture responses are well maintained over a 35-min period when stimulated by ACh every 5 min. Stimulation by ACh after 1, 20 and 40 min in O-Ca-Mg ASW results in a reduction of ACh contracture response to 15% of the response in Ca ASW. Similar treatment in O-Ca-Ni ASW reduces the ACh contracture response to 4%. Potassium and caffeine contracture responses at 1, 20 and 40 min in O-Ca-Mg ASW are reduced to 25 and 28%. Similar treatment in O-Ca-Ni ASW produces a block of potassium contracture response and reduces caffeine contracture response to 3%. Our 45Ca uptake data demonstrate that calcium influx is not required for the ACh contracture responses of anterior byssus retractor muscle.
用镍替代人工海水中的钙会导致钙以单指数速率流失（时间常数τ = 23.2分钟），并且紫贻贝前足丝牵缩肌对乙酰胆碱（ACh）的挛缩反应丧失。ACh挛缩反应以两种速率丧失；93%的ACh挛缩反应迅速丧失（时间常数τ = 7.43分钟），其余7%的ACh挛缩反应缓慢丧失（时间常数τ = 66.6分钟）。ACh挛缩反应丧失的快速阶段与镍的快速指数摄取相对应（时间常数τ = 6.5分钟）。ACh挛缩反应的丧失归因于镍将钙从膜释放位点置换出来。在O - Ca - Mg人工海水中，每5分钟用ACh刺激时，ACh挛缩反应在35分钟内得到很好的维持。在O - Ca - Mg人工海水中分别在1、20和40分钟后用ACh刺激，会使ACh挛缩反应降低至钙人工海水中反应的15%。在O - Ca - Ni人工海水中进行类似处理会使ACh挛缩反应降低至4%。在O - Ca - Mg人工海水中，1、20和40分钟时钾和咖啡因的挛缩反应分别降低至25%和28%。在O - Ca - Ni人工海水中进行类似处理会导致钾挛缩反应受阻，并使咖啡因挛缩反应降低至3%。我们的⁴⁵Ca摄取数据表明，前足丝牵缩肌的ACh挛缩反应不需要钙内流。
