Effects of nitrates and calcium channel blockers on Ca2+-ATPase in the microsomal fraction of porcine coronary artery smooth muscle cells.
Cell Calcium
; 8(5): 397-410, 1987 Oct.
Article
em En
| MEDLINE
| ID: mdl-2962738
ABSTRACT
The effects of the antianginal drugs nitroglycerin, nicorandil, diltiazem, verapamil and nicardipine on the activity of calcium-stimulated magnesium-dependent ATPase (Ca2+-ATPase) were investigated in the microsomal fraction from porcine coronary artery smooth muscle cells. Two discrete Ca2+-dependent ATPase components were observed [1] a high affinity component, which was a specific Ca2+-ATPase, [with a half saturation constant for Ca2+ (Km) of 0.44 microM, and maximum velocity (Vmax) of 124.3 pmol of phosphate (Pi) released/micrograms of protein/30 min] [2] a low affinity component in which Ca2+ could be replaced by Mg2+ without loss of its activity. Nitroglycerin and nicorandil (1 microM and 10 microM) both stimulated the activity of the Ca2+-ATPase significantly [142 +/- 12 (mean +/- standard error), and 137 +/- 10% of the control with nitroglycerin, and 152 +/- 17 and 135 +/- 20% with nicorandil] at a Ca2+ concentration of 0.3 microM. Diltiazem, verapamil and nicardipine did not cause significant stimulation. Nitroglycerin and nicorandil (1 microM), significantly decreased the Km for Ca2+ from the control value of 0.44 +/- 0.06 microM to 0.26 +/- 0.03 and 0.22 +/- 0.03 microM, respectively. Nitroglycerin and nicorandil may dilate coronary arteries by stimulating this Ca2+ extrusion pump enzyme through reduction of intracellular Ca2+ in smooth muscle cells.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Vasodilatadores
/
Bloqueadores dos Canais de Cálcio
/
ATPases Transportadoras de Cálcio
/
Microssomos
/
Músculo Liso Vascular
/
Nitratos
Limite:
Animals
Idioma:
En
Revista:
Cell Calcium
Ano de publicação:
1987
Tipo de documento:
Article
País de afiliação:
Japão