Effects of lotusine on the action potentials in myocardium and slow inward current in cardiac purkinje fibers
- VernacularTitle:洛土辛对心肌动作电位及犬浦肯野纤维慢内电流的影响
- Author:
Jialing WANG
;
Zhifang ZHAO
;
Weixin YAO
;
Mingxing JIANG
;
- Publication Type:Journal Article
- Keywords:
lotusine;
action potentials;
slow inward current;
phosphodiesterase
- From:
Chinese Pharmacological Bulletin
1986;0(06):-
- CountryChina
- Language:Chinese
-
Abstract:
AIM To study the effects of Lotusine(Lot), a pure alkaloid extracted from the green seed embryo of Nelumbo nucifera Gaertn, on the action potentials(APs) in myocardium and slow inward current(Isi) in cardiac Purkinje fibers(PF). METHODS standard microelectrode and two microelectrodes voltage clamp techniques were used. RESULTS Lot 1～100 ?mol?L -1 could concentration dependently prolonged APD 20 and APD 90 of fast AP and increase the contractile force(Fc) in guinea pig papillary muscles. In papillary muscles pretreated with reserpine, similar results were also observed but the effect of Lot was weaker than those pretreated without reserpine. In guinea pig left atria, Lot 30 ?mol?L -1 could partly antigoniste the shortening APD effect of acetylcholine. Lot 3～100 ?mol?L -1 could enhance the action potential amplitude(APA)and maximal velocity of phase 0 depolarization ( V max ) of slow AP of papillary muscles induced by high K + (24 mmol?L -1 )and isolated sinoatral node(SAN) pacemaker cells of rabbits with dose dependent manner,But not obvousely short the sinus cycle length of SAN. Moreover, Lot increased the Isi of in canin cardiac PF with with time dependent and dose dependent manner. CONCLUSION The results suggest that Lot has effect of prolongation of APD and increase of Ca 2+ influx and these are very important in contribution to its positive inotropic effect, which may be related to inhibition of phosphodiesterase Ⅲ.
