Halothane Inhibits the Cholinergic‐receptor-mediated Influx of Calcium in Primary Culture of Bovine Adrenal Medulla Cells
Halothane Inhibits the Cholinergic‐receptor-mediated Influx of Calcium in Primary Culture of Bovine Adrenal Medulla Cells
复制标题
氟烷抑制牛肾上腺髓质细胞原代培养物中胆碱能受体介导的钙内流
DOI：
10.1097/00000542-198604000-00009
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发表时间：
1986
期刊：
影响因子：
8.8
通讯作者：
F. Izumi
中科院分区：
文献类型：
--
作者：
N. Yashima;A. Wada;F. Izumi
肾上腺髓质细胞是胆碱能感受性细胞。刺激乙酰胆碱受体导致钙内流到细胞内，而钙是刺激-分泌耦合的耦合器。在这项研究中，作者利用培养的牛肾上腺髓质细胞，研究了氟烷对受体介导的45Ca内流的影响。临床浓度(0.5-2%)的氟烷抑制卡巴胆碱引起的~(45)Ca内流，同时抑制儿茶酚胺的分泌。高浓度镁可抑制钾去极化引起的~(45)Ca内流和儿茶酚胺的分泌，并与钙在钙通道上竞争，但不受氟烷的抑制。增加卡巴胆碱浓度不能克服氟烷对~(45)Ca内流的抑制作用。用Scatchard分析比较了氟烷和高浓度镁对~(45)Ca内流的抑制作用及其与外界钙浓度的关系。氟烷可减少45Ca的最大内流，但不改变钙-钙通道的表观动力学常数。相反，较大浓度的镁增加了表观动力学常数，但不改变45Ca的最大内流。根据这些发现，作者认为氟烷对~(45)Ca内流的抑制不是由于钙通道的直接竞争抑制，也不是由于激动剂-受体相互作用的竞争性拮抗。氟烷可能通过干扰受体和钙通道之间的偶联来抑制受体介导的钙通道的激活。
Adrenal medulla cells are cholinoceptive cells. Stimulation of the acetylcholine receptor causes the influx of Ca to the cells, and Ca acts as the coupler of the stimulus–secretion coupling. In this study, the authors investigated the effects of halothane on the receptor-mediated influx of 45Ca using cultured bovine adrenal medulla cells. Halothane at clinical concentrations (0.5–2%) inhibited the influx of 45Ca caused by carbachol, with simultaneous inhibition of catecholamine secretion. The influx of 45Ca and the secretion of catecholamines caused by K depolarization were inhibited by a large concentration of Mg, which competes with Ca at Ca channels, but not inhibited by halothane. Inhibition of the 45Ca influx by halothane was not overcome by increase in the carbachol concentration. Inhibition of the 45Ca influx by halothane was examined in comparison with that caused by a large concentration of Mg by the application of Scatchard analysis as the function of the external Ca concentration. Halothane decreased the maximal influx of 45Ca without altering the apparent kinetic constant of Ca to Ca channels. On the contrary, a large concentration of Mg increased the apparent kinetic constant without altering the maximal influx of 45Ca. Based on these findings, the authors suggest that inhibition of the 45Ca influx by halothane was not due to the direct competitive inhibition of Ca channels, nor to the competitive antagonism of agonist-receptor interaction. As a possibility, halothane seems to inhibit the receptor-mediated activation of Ca channels through the interference of coupling between the receptor and Ca channels.