Bloomquist E, Curtis B A
Am J Physiol. 1975 Nov;229(5):1244-8. doi: 10.1152/ajplegacy.1975.229.5.1244.
Calcium in the artificial seawater bathing whole Mytilus anterior byssus retractor muscles (ABRM) was measured by a specific Ca electrode under various conditions of activation, catch, and catch relaxation. Activation in response to ACh was associated with uptake of Ca by the muscles. Phasic contractions produced a small Ca uptake; catch contractions produced a larger and sustained Ca uptake. After tension relaxation, the muscle lost an amount of Ca roughly equal to that gained. Catch relaxation by 5-hydroxytryptamine (5HT) was associated with Ca release. ACh at identical concentrations, applied to the muscle for increasingly longer times, produced increasing amounts of Ca uptake. Regardless of the previous gain of Ca by the muscle, 5HT applied for a constant interval caused release of the same amount of Ca. A model for the Ca control system in ABRM based on this and previously obtained 45Ca efflux data is proposed.
在不同的激活、强直收缩和强直收缩松弛条件下，使用特定的钙离子电极测量了人工海水中浸泡的贻贝前足丝牵缩肌（ABRM）中的钙离子含量。对乙酰胆碱（ACh）的反应激活与肌肉对钙离子的摄取有关。相位收缩产生少量的钙离子摄取；强直收缩产生更大且持续的钙离子摄取。张力松弛后，肌肉损失的钙离子量大致与摄取的量相等。5-羟色胺（5HT）引起的强直收缩松弛与钙离子释放有关。相同浓度的ACh作用于肌肉的时间越来越长，会产生越来越多的钙离子摄取。无论肌肉之前摄取了多少钙离子，在固定间隔施加5HT都会导致相同量的钙离子释放。基于此以及之前获得的45Ca流出数据，提出了一个ABRM中钙离子控制系统的模型。
