Department of Internal Medicine, Division of Cardiology, Kiang Wu Hospital, Macau, China.
Cardiovascular Division, Fu Jen Catholic University Hospital, Fu Jen Catholic University, New Taipei City; Department of Cardiology, Lotung Poh-Ai Hospital, Yilan County, Taiwan.
Chin J Physiol. 2021 Mar-Apr;64(2):80-87. doi: 10.4103/cjp.cjp_93_20.
Ca-sensing receptors (CaSR), activated by elevated concentrations of extracellular Ca, have been known to regulate functions of thyroid cells, neurons, and endothelial cells (EC). In this report, we studied CaSR-mediated Ca influx in mouse cerebral microvascular EC (bEND.3 cells). Cytosolic free Ca concentration and Mn influx were measured by fura-2 microfluorometry. High (3 mM) Ca (CaSR agonist), 3 mM spermine (CaSR agonist), and 10 μM cinacalcet (positive allosteric modulator of CaSR) all triggered Ca influx; however, spermine, unlike high Ca and cinacalcet, did not promote Mn influx and its response was poorly sensitive to SKF 96365, a TRP channel blocker. Consistently, 2-aminoethoxydiphenyl borate and ruthenium red (two other general TRP channel blockers) suppressed Ca influx triggered by cinacalcet and high Ca but not by spermine. Ca influx triggered by high Ca, spermine, and cinacalcet was similarly suppressed by A784168, a potent and selective TRPV1 antagonist. Our results suggest that CaSR activation triggered Ca influx via TRPV1 channels; intriguingly, pharmacological, and permeability properties of such Ca influx depended on the stimulating ligands.
钙敏感受体（CaSR），在细胞外钙浓度升高时被激活，已被证明可以调节甲状腺细胞、神经元和内皮细胞（EC）的功能。在本报告中，我们研究了 CaSR 介导的小鼠大脑微血管内皮细胞（bEND.3 细胞）中的 Ca 内流。通过 fura-2 微荧光计测量细胞质游离 Ca 浓度和 Mn 内流。高浓度 Ca（CaSR 激动剂）、3 mM 亚精胺（CaSR 激动剂）和 10 μM 西那卡塞（CaSR 的正变构调节剂）都触发了 Ca 内流；然而，亚精胺与高 Ca 和西那卡塞不同，它不促进 Mn 内流，并且其反应对 TRP 通道阻滞剂 SKF 96365 的敏感性较差。一致地，2-氨基乙氧基二苯硼酸盐和钌红（两种其他通用 TRP 通道阻滞剂）抑制了西那卡塞和高 Ca 触发的 Ca 内流，但不抑制亚精胺触发的 Ca 内流。高 Ca、亚精胺和西那卡塞触发的 Ca 内流也被 TRPV1 拮抗剂 A784168 类似抑制。我们的结果表明，CaSR 激活通过 TRPV1 通道触发 Ca 内流；有趣的是，这种 Ca 内流的药理学和通透性特性取决于刺激配体。
