Endothelin-induced changes in intracellular calcium concentration in rat vascular smooth muscle cells: effects of extracellular calcium and atrial natriuretic factor.
The purpose of this study was to examine whether different mechanisms might underlie the changes in intracellular calcium concentration ([Ca2+]i) stimulated by high and low concentrations of endothelin, and whether atrial natriuretic factor (ANF) has an inhibitory effect on endothelin-induced [Ca2+]i changes in cultured rat vascular smooth muscle cells (VSMCs). In calcium-replete buffer, cultured monolayers of rat VSMCs superfused with endothelin at a high concentration (10 nM) exhibited a marked transient rise in [Ca2+]i, followed by a sustained elevation, whereas a low concentration of endothelin (0.1 nM) induced a sustained monophasic elevation. When calcium-free buffer was used, 10 nM endothelin induced a transient rise in [Ca2+]i of lesser amplitude, whereas 0.1 nM endothelin did not produce a significant rise. Pretreatment of VSMCs with ANF and cosuperfusion with endothelin failed to inhibit either transient or sustained endothelin-induced changes in [Ca2+]i in calcium-replete buffer.
Nakamura
M
M
Department of Cardiology, Princess Margaret Hospital, Christchurch, New Zealand.
Abell
T J
TJ
Richards
A M
AM
Ikram
H
H
Espiner
E A
EA
Yandle
T G
TG
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000502:physiology*; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000502:physiology*; D046508:Culture Techniques; D016232:Endothelins / Q000502:physiology*; D005110:Extracellular Space / Q000378:metabolism*; D007424:Intracellular Fluid / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D014661:Vasoconstriction / Q000502:physiology*
D015220:Calcium Channels; D016232:Endothelins; C472610:atrial natriuretic peptide, rat; D009320:Atrial Natriuretic Factor; D002118:Calcium