Inositol 1,4,5-trisphosphate-induced calcium release from platelet plasma membrane vesicles

Biochem Biophys Res Commun. 1988 Feb 15;150(3):1021-6. doi: 10.1016/0006-291x(88)90731-0.

Abstract

A platelet membrane preparation, enriched in plasma membrane markers, took up 45Ca2+ in exchange for intravesicular Na+ and released it after the addition of inositol 1,4,5-trisphosphate (IP3). The possibility that contaminating dense tubular membrane (DTS) vesicles contributed the Ca2+ released by IP3 was eliminated by the addition of vanadate to inhibit Ca+-ATPase-mediated DTS Ca2+ sequestration and by the finding that only plasma membrane vesicles exhibit Na+-dependent Ca2+ uptake. Ca2+ released by IP3 was dependent on low extravesicular Ca2+ concentrations. IP3-induced Ca2+ release was additive to that released by Na+ addition while GTP or polyethylene glycol (PEG) had no effect. These results strongly suggest that IP3 facilitates extracellular Ca2+ influx in addition to release from DTS membranes.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenosine Triphosphate / pharmacology
  • Blood Platelets / drug effects
  • Blood Platelets / metabolism*
  • Calcium / blood*
  • Calcium Radioisotopes
  • Cell Membrane / metabolism
  • Guanosine Triphosphate / pharmacology
  • Humans
  • Inositol 1,4,5-Trisphosphate
  • Inositol Phosphates / pharmacology*
  • Kinetics
  • Polyethylene Glycols / pharmacology
  • Sodium / blood
  • Sugar Phosphates / pharmacology*
  • Vanadates / pharmacology

Substances

  • Calcium Radioisotopes
  • Inositol Phosphates
  • Sugar Phosphates
  • Vanadates
  • Polyethylene Glycols
  • Inositol 1,4,5-Trisphosphate
  • Guanosine Triphosphate
  • Adenosine Triphosphate
  • Sodium
  • Calcium