Vascular bed and vasoconstrictor-dependent selectivity of the calcium channel antagonist, PN 200-110

The potency of the dihydropyridine calcium channel blocker, PN 200-110 was assessed in vitro against contractions induced by potassium (20-55 mM) and histamine (1-300 microM) in rabbit thoracic aorta, coronary, basilar, renal and central ear arteries. PN 200-110 was particularly effective against potassium responses in the coronary and basilar arteries (IC50 30 and 50 pM) and of little effect against histamine responses in the renal artery and thoracic aorta (IC50 greater than 1 microM). These results suggest that PN 200-110 has some preferential actions dependent on both the vascular bed and also the constrictor used.