Mechanism of angiotensin II stimulation of Na-K-Cl cotransport of vascular smooth muscle cells

N. E. Owen, K. M. Ridge

Research output: Contribution to journalArticlepeer-review

21 Scopus citations

Abstract

Previous studies from this laboratory have demonstrated that Na-K-Cl cotransport of vascular smooth muscle cells is inhibited by hormones that increase intracellular adenosine 3',5'-cyclic monophosphate (cAMP) levels (e.g., catecholamines) and is stimulated by hormones that increase intracellular guanosine 3',5'-cyclic monophosphate (cGMP) levels (e.g., atrial natriuretic peptides). Others have suggested that calcium may also modulate Na-K-Cl cotransport of vascular smooth muscle cells. The goal of the present study was to characterize the mechanisms of angiotensin II stimulation of Na-K-Cl cotransport of early passage cultured vascular smooth muscle cells. We found that when vascular smooth muscle cells were treated with angiotensin II or a calcium ionophore, Na-K-Cl cotransport was markedly enhanced above basal levels. We found that when calcium influx was blocked with the calcium chelator EDTA or with three different chemical types of calcium-channel blockers, the stimulatory effects of angiotensin II on Na-K-Cl cotransport were markedly inhibited. Furthermore, when intracellular calcium mobilization was blocked with high concentrations of the calcium chelator quin2 or with the intracellular calcium antagonist 8-(diethylamino)octyl 3,4,5-trimethoxybenzoate (TMB-8), the stimulatory effects of angiotensin II on Na-K-Cl cotransport were also substantially inhibited. These results suggest that both calcium influx via receptor-operated calcium channels and intracellular calcium mobilization may play a role in stimulation of Na-K-Cl cotransport of vascular smooth muscle cells in response to angiotensin II.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Cell Physiology
Volume257
Issue number4
StatePublished - Jan 1 1989

ASJC Scopus subject areas

  • Cell Biology
  • Clinical Biochemistry
  • Physiology

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