Lee K S, Ladinsky H, Choi S J, Kasuya Y
J Gen Physiol. 1966 Mar;49(4):689-715. doi: 10.1085/jgp.49.4.689.
Sarcoplasmic reticulum fragments (S.R.F.) were isolated from skeletal and heart muscles. These fragments were found to take up Ca(++) very actively from media. When monophasic square waves were passed through the S.R.F. suspension, the Ca(++) uptake by S.R.F. was decreased. When the suspension was stimulated electrically after the Ca(++) was taken up by S.R.F., the initiation and the cessation of the stimulation were followed by the release and re-uptake of Ca(++) by S.R.F., respectively. The degree of inhibition of the Ca(++) uptake as well as of the Ca(++) release by electrical stimulation was dependent on the voltage and the frequency of stimulation. The presence of inorganic phosphate or oxalate modified the influence of electrical stimulation on the release and the uptake of Ca(++) by S.R.F. Attempts were made to observe the release of Ca(++) by electrical stimulation from unfractionated sarcoplasmic reticulum remaining in myofibers, and the interaction of the released Ca(++) with myofibrils in vitro. For this purpose, the glycerol-extracted fiber was selected as a muscle model, since it contains both sarcoplasmic reticulum and myofibrils. It was found that electrical stimulation of skeletal and heart glycerol-extracted fibers resulted in the contraction of fibers. It appeared that the contraction of glycerol fibers by electrical stimulation was caused by the Ca(++) release from sarcoplasmic reticulum by stimulation.
从骨骼肌和心肌中分离出肌浆网碎片（S.R.F.）。发现这些碎片能非常活跃地从培养基中摄取钙离子（Ca(++)）。当向S.R.F.悬浮液施加单相方波时，S.R.F.对Ca(++)的摄取减少。当Ca(++)被S.R.F.摄取后对悬浮液进行电刺激时，刺激的开始和停止分别伴随着S.R.F.对Ca(++)的释放和重新摄取。电刺激对Ca(++)摄取以及Ca(++)释放的抑制程度取决于刺激的电压和频率。无机磷酸盐或草酸盐的存在改变了电刺激对S.R.F.释放和摄取Ca(++)的影响。尝试观察电刺激从肌纤维中残留的未分级肌浆网释放Ca(++)，以及释放的Ca(++)与体外肌原纤维的相互作用。为此，选择甘油抽提纤维作为肌肉模型，因为它同时含有肌浆网和肌原纤维。发现对骨骼肌和心脏甘油抽提纤维进行电刺激会导致纤维收缩。似乎电刺激引起甘油纤维收缩是由于刺激使肌浆网释放Ca(++)所致。
