Endothelin evoked Ca2+ transients and oscillations in A10 vascular smooth muscle cells.
Endothelin (200 nM) evoked a rapid rise in [Ca2+]i which was then followed by a maintained elevation of [Ca2+]i. The initial transient can be explained by the release of stored Ca2+ whilst the maintained plateau is likely to be an influx of Ca2+ as it was partially inhibited by nifedipine (5 microM) and the remaining component abolished by the removal of extracellular Ca2+. Vasopressin (1 nM) evoked a similar response which also showed a nifedipine insensitive component to it's plateau phase. Endothelin also evoked oscillations in [Ca2+]i; these where characterised by a rapid rising phase followed by a slower decline, with no 'pacemaker' rise in [Ca2+]i preceding the rising phase. The oscillations were inhibited by the addition of 5 microM nifedipine or the removal of extracellular Ca2+ suggesting they are at least in part dependent on voltage gated Ca2+ entry.
Simpson
A W
AW
University Laboratory of Physiology, Oxford, UK.
Ashley
C C
CC
D000818:Animals; D001572:Benzofurans; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D004533:Egtazic Acid / Q000494:pharmacology; D016232:Endothelins; D004730:Endothelium, Vascular / Q000502:physiology*; D005456:Fluorescent Dyes; D016257:Fura-2; D007700:Kinetics; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D009543:Nifedipine / Q000494:pharmacology; D009991:Oscillometry; D010455:Peptides / Q000494:pharmacology*; D014667:Vasopressins / Q000494:pharmacology
D001572:Benzofurans; D016232:Endothelins; D005456:Fluorescent Dyes; D010455:Peptides; D014667:Vasopressins; D004533:Egtazic Acid; D009543:Nifedipine; D002118:Calcium; D016257:Fura-2