Prakash Y S, Togaibayeva A A, Kannan M S, Miller V M, Fitzpatrick L A, Sieck G C
Departments of Anesthesiology, Physiology and Biophysics, Surgery, and Endocrinology, Mayo Foundation, Rochester 55905, USA.
Am J Physiol. 1999 Mar;276(3):H926-34. doi: 10.1152/ajpheart.1999.276.3.H926.
Acute estrogen administration relaxes vascular smooth muscle by decreasing intracellular Ca2+ concentration ([Ca2+]i). In the present study, we examined the hypothesis that this reduction in [Ca2+]i is mediated in part by enhanced Ca2+ efflux. Coronary artery smooth muscle cells were isolated from gonad-intact, sexually mature female pigs. The [Ca2+]i response to endothelin-1 was measured using fluo 3 and confocal microscopy. 17beta-Estradiol (E2beta), but not 17alpha-estradiol or triamcinolone acetonide, caused a concentration-dependent (IC50 = 10 nM) decrease in the [Ca2+]i response to endothelin-1. This decrease was blocked by the specific estrogen receptor antagonist ICI-182780. Under conditions in which Ca2+ influx and sarcoplasmic reticulum Ca2+ reuptake were blocked, E2beta still decreased [Ca2+]i. The response was blocked by extracellular lanthanum. These data indicate that E2beta decreases [Ca2+]i in coronary artery smooth muscle by affecting Ca2+ efflux via a receptor-mediated mechanism.
急性给予雌激素可通过降低细胞内钙离子浓度（[Ca2+]i）来舒张血管平滑肌。在本研究中，我们检验了这样一个假说，即[Ca2+]i的这种降低部分是由增强的钙离子外流介导的。从性腺完整、性成熟的雌性猪分离出冠状动脉平滑肌细胞。使用Fluo 3和共聚焦显微镜测量对内皮素-1的[Ca2+]i反应。17β-雌二醇（E2β），而非17α-雌二醇或曲安奈德，引起对内皮素-1的[Ca2+]i反应呈浓度依赖性（IC50 = 10 nM）降低。这种降低被特异性雌激素受体拮抗剂ICI-182780阻断。在钙离子内流和肌浆网钙离子再摄取被阻断的条件下，E2β仍可降低[Ca2+]i。该反应被细胞外镧阻断。这些数据表明，E2β通过受体介导机制影响钙离子外流，从而降低冠状动脉平滑肌中的[Ca2+]i。
