Inositol phosphate production and Ca2+ mobilization in human umbilical-vein endothelial cells stimulated by thrombin and histamine.
Human umbilical-vein endothelial cells (HUVECs) were cultured, and their inositol phosphate formation and Ca2+ mobilization in response to thrombin and histamine were studied. Evidence from measurement of intracellular Ca2+ in the absence of extracellular Ca2+ established that the two agonists were both acting on a single cell population, and suggested that a Ca2+-influx component was stimulated which was dependent on receptor-occupancy. After 30 s of stimulation in the presence of 10 mM-LiCl, the effects of 20 microM-histamine and 1 unit of thrombin/ml on formation of inositol phosphates were additive, but at 5 min they were not. HUVECs labelled with myo-[3H]inositol for 72 h synthesized radiolabelled inositol pentakis- and hexakis-phosphate. The predominant isomers of inositol mono-, bis- and tris-phosphates whose formation was stimulated were the 4-phosphate, the 1,4-bisphosphate and the 1,3,4-trisphosphate.
Pollock
W K
WK
Department of Biochemistry, AFRC Institute of Animal Physiology, Babraham, Cambridge, U.K.
Wreggett
K A
KA
Irvine
R F
RF
D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism*; D006632:Histamine / Q000494:pharmacology; D006801:Humans; D007295:Inositol Phosphates / Q000378:metabolism*; D007536:Isomerism; D013403:Sugar Phosphates / Q000378:metabolism*; D013917:Thrombin / Q000494:pharmacology; D014471:Umbilical Veins / Q000378:metabolism*
D007295:Inositol Phosphates; D013403:Sugar Phosphates; D006632:Histamine; D013917:Thrombin; D002118:Calcium