Differential blockade of agonist- and depolarization-induced super(45)Ca super(2+) influx in smooth muscle cells

ATP stimulated super(45)Ca super(2+) influx in rat aortic smooth muscle cells in a concentration-dependent manner. ADP and GTP were less effective than ATP in stimulating super(45)Ca super(2+) influx. The data indicate that ATP-stimulated Ca super(2+) influx in rat aortic smooth muscle cells is resistant to darodipine but is reduced by La super(3+), Cd super(2+), and other inorganic blockers of Ca super(2+) channels. (DBO)