Chloride-dependent calcium transients induced by angiotensin II in vascular smooth muscle cells

Yunn Hwa Ma*, Hsiao Wen Wei, Kwan Hwa Su, Harlan E. Ives, R. Curtis Morris

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

5 Scopus citations

Abstract

Cl- is essential for the vasoconstrictive response to angiotensin II (ANG II). In vascular smooth muscle cells (VSMC), we determined whether ANG II-induced transient increase in intracellular Ca2+ concentration ([Ca2+]i) is Cl- dependent. After incubating the cells at different extracellular Cl- concentration ([Cl-]e) for 40 min, the ANG II-induced Ca2+ transients at 120 meq/l Cl- were more than twice those at either 80 or 20 meq/l Cl-. Replacing Cl- with bicarbonate or gluconate yielded similar results. In addition, after removal of extracellular Ca2+, ANG II-induced as well as platelet-derived growth factor-induced Ca2+ release exhibited Cl- dependency. The difference of Ca2+ release with high vs. low [Cl -]e was not affected by acutely altering [Cl -]e 1 min before administration of ANG II when [Cl -]i was yet to be equilibrated with [Cl-] e. Pretreatment of a Cl- channel inhibitor, 5-nitro-2-(3-phenylpropylamino)benzoic acid, increased ANG II-induced Ca 2+ release and entry at 20 meq/l Cl- but did not alter those at 120 meq/l Cl-. However, after equilibration, a reduced [Cl-]c did not affect thapsigargin-induced Ca 2+ release, suggesting that Cl- may not affect the size of intracellular Ca2+ stores. Nevertheless, at high [Cl-], the peak increase of inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] induced by ANG II was approximately sixfold that at low [Cl-]. Thus the Cl--dependent effects of ANG II on Ca2+ transients may be mediated, at least in part, by a Cl--dependent Ins(1,4,5)P3 accumulation in VSMC.

Original languageEnglish
Pages (from-to)C112-C118
JournalAmerican Journal of Physiology - Cell Physiology
Volume286
Issue number1 55-1
DOIs
StatePublished - 01 2004

Keywords

  • Anion
  • Ca release
  • Inositol 1,4,5-trisphosphate

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