Inhibition of calcium transients in cultured vascular smooth muscle cells by pertussis toxin.
Effects of pertussis toxin on Ca2+ transients in rat arterial smooth muscle cells in primary culture were monitored, using quin 2-microfluorometry. In the presence or the absence of extracellular Ca2+, norepinephrine, histamine, caffeine and high extracellular K+ induced elevations in cytosolic Ca2+ concentration. Cytosolic Ca2+ elevations induced by norepinephrine and histamine were inhibited by pretreatment of the cells with pertussis toxin, time- and dose-dependently. However, elevations induced by caffeine and K+-depolarization were unaffected by the pretreatment with this toxin. Thus, it is suggested that GTP binding protein, a pertussis toxin substrate and involved in the receptor-mediated cytosolic Ca2+ transients, is not involved in transient elevations in cytosolic Ca2+ induced by caffeine and K+-depolarization in cultured vascular smooth muscle cells.
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D019204:GTP-Binding Proteins / Q000502:physiology; D006632:Histamine / Q000494:pharmacology; D007295:Inositol Phosphates / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D009638:Norepinephrine / Q000494:pharmacology; D037342:Pertussis Toxin; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D010566:Virulence Factors, Bordetella / Q000494:pharmacology*
D007295:Inositol Phosphates; D010566:Virulence Factors, Bordetella; D006632:Histamine; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins; D011188:Potassium; D002118:Calcium; D009638:Norepinephrine