Calcium antagonistic action of N-ethyl perhexiline maleate

N-ethyl perhrxilline (1, 1-dicyclohexyl-2-[2’(N-ethyl)piperidyl]ethane, NEP) exerted a negative inotropic action in isolated rabbit’s atrium and inhibited spontaneous beat frequency in isolated rabbit’s right atrium, which was antagonized by high concentration of exogenous Ca2+. NEP shifted the dose-effect curve to right in K+-depolarized taenia coli of guinea pig with PD’2 5.01 in contrast to that of perhexilline 4.90. NEP 71 microM inhibited the concentration induced by K+ at 6.25 microM and depressed the contraction induced by noradrenaline 0.6 microM significantly in isolated strips of rabbit’s aorta. It is suggested that the site acted by NEP may be at the potential-dependent Ca2+ channel in membrane of smooth muscle.