Evidence in favor of a calcium-sensing receptor in arterial endothelial cells: Studies with calindol and Calhex 231

Arthur H. Weston, Mais Absi, Donald T. Ward, Jacqueline Ohanian, Robert H. Dodd, Philippe Dauban, Christophe Petrel, Martial Ruat, Gillian Edwards

    Research output: Contribution to journalArticlepeer-review

    Abstract

    Small increases in extracellular Ca2+ dilate isolated blood vessels. In the present study, the possibility that a vascular, extracellular Ca2+-sensing receptor (CaSR) could mediate these vasodilator actions was investigated. Novel ligands that interact with the CaSR were used in microelectrode recordings from rat isolated mesenteric and porcine coronary arteries. The major findings were that (1) raising extracellular Ca2+ or adding calindol, a CaSR agonist, produced concentration-dependent hyperpolarizations of vascular myocytes, actions attenuated by Calhex 231, a negative allosteric modulator of CaSR. (2) Calindol-induced hyperpolarizations were inhibited by the intermediate conductance, Ca2+-sensitive K + (IKca) channel inhibitors, TRAM-34, and TRAM-39. (3) The effects of calindol were not observed in the absence of endothelium. (4) CaSR mRNA and protein were present in rat mesenteric arteries and in porcine coronary artery endothelial cells. (5) CaSR and IKca proteins were restricted to caveolin-poor membrane fractions. We conclude that activation of vascular endothelial CaSRs opens endothelial cell IKca channels with subsequent myocyte hyperpolarization. The endothelial cell CaSR may have a physiological role in the control of arterial blood pressure. © 2005 American Heart Association, Inc.
    Original languageEnglish
    Pages (from-to)391-398
    Number of pages7
    JournalCirculation research
    Volume97
    Issue number4
    DOIs
    Publication statusPublished - 19 Aug 2005

    Keywords

    • Calcium-sensing receptor
    • Calhex 231
    • Calindol
    • Endothelium
    • Potassium channel

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