Estrogen increases Ca2+ efflux from female porcine coronary arterial smooth muscle

Y. S. Prakash, A. A. Togaibayeva, M. S. Kannan, V. M. Miller, L. A. Fitzpatrick, G. C. Sieck

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62 Scopus citations


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. 17β-Estradiol (E2β), but not 17α-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, E2β still decreased [Ca2+](i). The response was blocked by extracellular lanthanum. These data indicate that E2β decreases [Ca2+](i) in coronary artery smooth muscle by affecting Ca2+ efflux via a receptor-mediated mechanism.

Original languageEnglish (US)
Pages (from-to)H926-H934
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Issue number3 45-3
StatePublished - Mar 1999


  • Calcium adenosine 5'-triphosphatase
  • Endothelin
  • Receptor
  • Vasodilation


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