Hyperglycemia alters cytoplasmic Ca2+ responses to capacitative Ca2+ influx in rat aortic smooth muscle cells

Academic Article

Abstract

  • Concentrations of free cytoplasmic Ca in rat aortic smooth muscle (RASM) cells were monitored using the ratiometric Ca indicator fura 2- acetoxymethyl ester (AM). In RASM cells cultured in 5 mM Glc, incubation with angiotensin II, ATP, or thapsigargin [a selective inhibitor of the sarcoplasmic reticulum (SR) Ca -ATPase] depleted SR Ca stores and initiated a capacitative Ca influx through the plasma membrane. This influx was resistant to verapamil, a selective inhibitor of L-type voltage- gated Ca channels, but was sensitive to SKF-96365, an inhibitor of the receptor-operated Ca entry pathway. RASM cells cultured in 25 mM Glc exhibited a significant decrease in cytoplasmic Ca responses to agonist- induced Ca release from SR stores and to subsequent capacitative Ca entry. In addition, the cytoplasmic response to thapsigargin-induced release of Ca from the SR in hyperglycemic cells peaked more sharply than in control cells and returned to baseline more rapidly. The effects of hyperglycemia were not overcome by myo-inositol supplementation. 2+ 2+ 2+ 2+ 2+ 2+ 2+ 2+ 2+ 2+ 2+
  • Authors

    Digital Object Identifier (doi)

    Author List

  • Rivera AA; White CR; Guest LL; Elton TS; Marchase RB
  • Volume

  • 269
  • Issue

  • 6 38-6