Mechanism of inhibitory effect of MN9202 on contraction and relaxation functions of cardiac myocyte
- VernacularTitle:MN9202抑制心肌细胞收缩、舒张机制的研究
- Author:
Xiaoxing ZHU
;
Qibing MEI
;
Li LIU
- Publication Type:Journal Article
- Keywords:
MN9202;
myocardium;
function of cell shortening;
function of cell relengthening
- From:
Medical Journal of Chinese People's Liberation Army
2001;0(11):-
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the inhibitory effect on enhancement of contraction and relaxation functions of cardiomyocytes induced by of MN9202 TEA, Forskolin, and MB. Methods The twitch amplitude was measured with a video edge tracker method. The following indexes, including ph (peak height), peak height/baseline percent (ph/bl, %), maximal velocity of contraction (+dL/dt) and maximal velocity of diastolization (-dL/dt), were recorded by a computer. Results TEA, Forskolin and MB increased electrically-induced contraction as shown by the following indexes: ph, ph/bl%, +dL/dt and -dL/dt. Forskolin and MB markedly augmented function of cardiac myocyte contraction and diastolization. Comparing with the control group, Forskolin (10-8mol/L) increased ph from 0.12?0.03(um)to 0.24?0.06 (um), ph/bl % from 12?3% to 27?6%, +dL/dt from 1.8?0.5 (um/s) to 3.8?0.9 (um/s), -dL/dt from 1.8?0.22 (um/s) to 3.5?0.7 (um/s). These indexes increased by 91%, 123%, 110% and 89%, respectively. MB also increased significantly; ph, ph/bl %, +dL/dt and -dL/dt were 0.14?0.04um, 11?4%, 2.2?0.3um/s and 2.2?0.6um/s, respectively. MN9202 (3?10~ -6mol/L) decreased the indexes (+dL/dt and -dL/dt ) which were increased by Forskolin significantly. Conclusion TEA, Forskolin and MB increased function of cardiac myocyte contraction and diastolization. These drugs might elevate intracellular calcium content indirectly and directly. The effects of TEA, Forskolin and MB were attenuated by MN9202. MN9202 might not only block Dihydropyridine Receptor, but might also inhibit calcium influx. Further study is needed to elucidate exact mechanism of MN9202.
