Abstract: AIM: To investigate the effects of acanthopanax senticosus saponins (ASS) on myocardial mitochondrial ATP sensitive potassium channel (mito K_ATP) and sarcolemmal ATP sensitive potassium channel (sarcol K_ATP) and to discuss the protection mechanisms of ASS on myocardial ischemia.METHODS: Ventricular myocytes of rabbits were isolated by enzymatic dissociation.Laser scanning confocal microscope (multi-photon) was used for observe the effects of ASS on mito K_ATP.The whole-cell patch clamp technique was used for observe the effects of ASS on sarcol K_ATP.RESULTS: There was no obvious variation of mitochondrial fluorescence intensity in control group during 10 min observation.Mitochondrial fluorescence intensity increased significantly in 30 mg·L^-1ASS group, 100 mg·L^-1ASS group and 300 mg·L^-1ASS group after administration.The increments were (14.8±3.56) %, (30.4±4.34) % and (38.4±5.68) %, respectively.3 μmol·L^-1of glibenclamide had no effect on mitochondrial fluorescence intensity, but it could block the effects of ASS on mitochondrial fluorescence intensity. There was no significant differences in the peak of I_K-ATP between the control group, 30 mg·L^-1ASS group, 100 mg·L^-1ASS group, and 300 mg·L^-1ASS group.CONCLUSION: ASS can open mito K_ATP, and it has no effect on sarcol K_ATP.The protection mechanism of ASS onmyocardial ischemia is related to opening mito K_ATP.

Key words: acanthopanax senticosus saponins, cardiac myocyte, ATP sensitive potassium channel, patchclamp, laser scanning confocal microscope