A calcium antagonist drug binding site in skeletal muscle sarcoplasmic reticulum: evidence for a calcium channel.
A calcium antagonist drug binding site in skeletal muscle sarcoplasmic reticulum: evidence for a calcium channel.
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骨骼肌肌浆网中的钙拮抗剂药物结合位点：钙通道的证据。
DOI：
10.1016/0024-3205(83)90807-x
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发表时间：
1983
期刊：
影响因子：
6.1
通讯作者：
David A. Beatty
中科院分区：
文献类型：
--
作者：
Alan S. Fairhurst;Stanley A. Thayer;Jack E. Colker;David A. Beatty
肌浆网（S.R.）已发现兔骨骼肌中含有钙拮抗剂药物[3 H] -尼群地平的单一高亲和力结合位点。研究了两个亚组分的网，重（HSR）和轻（LSR）的制剂，表现出类似的尼群地平平衡解离常数（KD）为1 nM。在相同条件下测定的粗制心肌和脑膜显示出0.2-0.3nM的KD值。每毫克的结合位点浓度。发现HSR中的蛋白质（Bmax）非常高，即6.7皮摩尔/mg，比LSR的蛋白质（Bmax）高约4倍。[3H]- 尼群地平与HSR的结合是可逆的，并被钙拮抗剂氟桂利嗪和维拉帕米以及细胞内钙释放拮抗剂TMB-8（8-二乙基氨基-辛基3，4，5-三甲基苯甲酸酯盐酸盐）抑制。然而，未标记的尼群地平（浓度为2 × 10− 5 M）对电刺激离体兔蚓状肌或大鼠膈肌的收缩没有影响，也不影响大鼠膈神经-膈肌标本中研究的神经肌肉接头。此外，2 × 10− 5 M尼群地平对HSR的净45 Ca摄取几乎没有影响。这些结果提示[~ 3 H] -尼群地平与骨骼肌S.R.类似于脑细胞膜，其也含有对[3 H] -尼群地平的高亲和性结合位点，并且类似地对这种二氢吡啶型Ca通道阻断剂不敏感。由于HSR也富含钙螯合蛋白和末端胱氨酸，在体内从其中释放钙，因此似乎可能S. R.与S.R.中的Ca通道相关。
The sarcoplasmic reticulum (S.R.) of rabbit skeletal muscle has been found to contain a single, high affinity binding site for the Ca antagonist drug [3H] -nitrendipine. Two subfractions of the reticulum were studied, the heavy (HSR) and light (LSR) preparations, which exhibited similar nitrendipine equilibrium dissociation constants (KD) of 1nM. Crude cardiac and brain membranes assayed under the same conditions exhibited KDvalues of 0.2–0.3nM. The concentration of binding sites per mg. protein (Bmax) in HSR was found to be very high, namely 6.7 picomoles/mg, some four times greater than that of LSR. [3H] -nitrendipine binding to HSR was reversible and inhibited by the Ca antagonists flunarizine and verapamil, and by the intracellular Ca release antagonist TMB-8 (8-diethylamino-octyl 3,4,5- trimethylbenzoate hydrochloride). However, unlabelled nitrendipine at 2 × 10−5M had no effect on contraction of isolated electrically stimulated rabbit lumbrical or rat diaphragm muscles, nor did it affect the neuromuscular junction as studied in rat phrenic nerve-diaphragm preparations. Also, little effect of 2 × 10−5M nitrendipine was seen on net45Ca uptake by HSR. These results suggest that [3H] -nitrendipine binding to skeletal muscle S.R. resembles that of brain membranes, which also contain a high affinity binding site for [3H] -nitrendipine and which similarly are pharmacologically insensitive to this dihydropyridine type of Ca channel blocking agent. Since HSR is also enriched in calsequestrin and terminal cysternae from which Ca is released in vivo, it seems likely that the [3H]- nitrendipine binding sites in S.R. are associated with Ca channels in the S.R.
大鼠大脑中[3H]尼群地平结合位点的放射自显影可视化：突触区的定位。
影响因子：
5
作者：
Murphy,KM;Gould,RJ;Snyder,SH
通讯作者：
Snyder,SH