Nakao S, Ebata H, Hamamoto T, Kagawa Y, Hirata H
Department of Biochemistry, Jichi Medical School, Tochigi, Japan.
Biochim Biophys Acta. 1988 Oct 20;944(3):337-43. doi: 10.1016/0005-2736(88)90503-2.
Highly purified sarcolemmal membranes, prepared from fresh bovine heart left ventricle, were solubilized by n-octyl beta-D-glucopyranoside and reconstituted into proteoliposomes with soybean phospholipids by the detergent-dialysis method. Ca2+ flux into the proteoliposomes was determined using the fluorescent probe Quin2. A membrane potential (negative in the proteoliposome interior) that was created by K+ diffusion mediated by valinomycin accelerated the Ca2+ influx. The voltage-dependent Ca2+ influx was dependent on pretreatment of the sarcolemmal membranes with Bay K 8644 and was inhibited by various calcium antagonists including nicardipine (K0.5 = 4.5.10(-7) M), verapamil (K0.5 = 9.2.10(-9) M), diltiazem (K0.5 = 26.10(-8) M) and omega-conotoxin (K0.5 = 9.5.10(-9) M).
从新鲜牛心脏左心室制备的高度纯化的肌膜，用正辛基-β-D-吡喃葡萄糖苷溶解，并通过去污剂透析法与大豆磷脂重组成蛋白脂质体。使用荧光探针喹啉-2测定进入蛋白脂质体的Ca2+通量。缬氨霉素介导的K+扩散产生的膜电位（蛋白脂质体内部为负）加速了Ca2+内流。电压依赖性Ca2+内流取决于用Bay K 8644对肌膜进行预处理，并受到包括尼卡地平（K0.5 = 4.5×10(-7) M）、维拉帕米（K0.5 = 9.2×10(-9) M）、地尔硫卓（K0.5 = 26×10(-8) M）和ω-芋螺毒素（K0.5 = 9.5×10(-9) M）在内的各种钙拮抗剂的抑制。
