Effects of electric stimulation applied during absolute refractory period on contraction and relaxation of ventricular myocytes in normal and failure guinea-pigs / 西安交通大学学报(医学版)

ABSTRACT

Objective To investigate the effect of electric stimulation applied during absolute refractory period on contraction and relaxation and Ca 2+ transient of ventricular myocytes from normal guinea-pigs. Methods The ventricular myocytes of guinea-pigs were obtained by enzyme digesting, and the extent of the contraction and relaxation and Ca 2+ transient were recorded through the motion edge detection system. The Ca 2+ transient was reflected by fluorescence ratio (360/380) ( F 360/F 380). Results The ventricular myocytes from the normal guinea-pigs ①The contraction extent of guinea-pig ventricular myocytes increased by (16.55?5.49)%. The peak velocity of shorting (contraction) and the peak velocity of relengthening (relaxation) increased by (17.43?7.08)% and (19.74?9.08)%, respectively(n=10); ②The extent of F 360/F 380 increased (25.79?6.88)%. The peak velocity of F 360/F 380 increased by (29.47?9.25)% and (22.52?7.81)% during shortening and relengthening, respectively(n=10). The ventricular myocytes from failure guinea-pigs ①The contraction extent of guinea-pig ventricular myocytes increased by (15.53?5.31)%. The peak velocity of shortening (contraction) and the peak velocity of relengthening (relaxation) increased by (10.60?3.02)% and (23.32?8.26)%, respectively(n=6); ②The extent of F 360/F 380 increased (16.82?7.03)%. The peak velocity of F 360/F 380 increased by (16.27?5.91)% and (10.32?2.46)% during shorenting and relengthening, respectively(n=6). Conclusion Appropriate electric stimulation applied during absolute refractory period might strengthen the contracting and relaxing function of normal and failing ventricular myocytes in guinea-pigs.