Benidipine, an anti-hypertensive drug, relaxes mouse airway smooth muscle

Abstract

AimsBenidipine is a dihydropyridine (DHP) derived Ca2+ antagonist, can block triple Ca2+ channels (L, N, and T). It has been used as a safety anti-hypertensive drug because of its long-acting relaxant effect on vascular smooth muscle (VSM). However, whether benidipine has similar pharmacological actions in airway smooth muscle (ASM) is unknown. This research aims to reveal the relaxant property and Ca2+ antagonistic effect of benidipine on ASM. Main methodsThe relaxant property of mouse ASM was investigated by tissue tension tests, and Ca2+ antagonistic effect was evaluated through patch-clamp techniques. Key findingsBenidipine caused dose-dependent relaxations on high K+ (80 mM) induced precontraction in mouse ASM, which relied on inhibition of extracellular Ca2+ influx, and 1 μM benidipine totally blocked L-type voltage-dependent Ca2+ channels (LVDCCs) currents in airway smooth muscle cells (ASMCs). Benidipine also showed dose-dependent inhibition of ACh-induced precontraction with or without the LVDCCs blocker nifedipine, and 100 μM benidipine blocked ACh-stimulated Ca2+ influx through not only LVDCCs but also non-selective cation channels (NSCCs). SignificanceBenidipine blocked LVDCCs and NSCCs to abolish these channels-mediated Ca2+ influx, which relaxed precontracted ASM. This study represented benidipine with a new potential medicinal value for ASM hypercontractility.