绝对不应期电刺激对健康和衰竭豚鼠心室肌细胞舒缩及钙瞬变的影响

目的　探讨绝对不应期电刺激对正常和慢性心力衰竭豚鼠心室肌细胞收缩幅度及同步钙瞬变的影响。方法　酶解分离心室肌细胞 ,应用单细胞收缩动缘测定仪 ,在基础刺激 (S1)同时给予绝对不应期电刺激 (S2 ) ,以F3 60 /F3 80 反映细胞钙瞬变 ,观察细胞收缩幅度和细胞钙瞬变的变化。结果　健康豚鼠心室肌细胞 :收缩幅值增高 (16 .5 5±5 .4 9) % ,收缩速度峰值增加 (17.4 3± 7.0 8) % ,舒张速度峰值增加 (19.74± 9.0 8) % (n =10 ) ;细胞收缩过程F3 60 /F3 80幅值增加 (2 5 .79± 6 .88) % ,F3 60 /F3 80 增高速度与减少速度分别增加 (2 9.4 7± 9.2 5 ) %和 (2 2 .5 2± 7.81) % (n =10 )。慢性心力衰竭豚鼠心室肌细胞 :收缩幅值增高 (15 .5 3± 5 .31) % ,收缩速度峰值增加 (10 .6 0± 3.0 2 ) % ,舒张速度峰值增加(2 3.32± 8.2 6 ) % (n =6 ) ;F3 60 /F3 80 幅值增加 (16 .82± 7.0 3) % ,F3 60 /F3 80 增高速度与减少速度分别增加 (16 .2 7± 5 .91) %和 (10 .32± 2 .4 6 ) % (n =6 )。结论　适宜的绝对不应期电刺激可增强健康和衰竭豚鼠心室肌细胞舒缩能力

Effects of electric stimulation applied during absolute refractory period on contraction and relaxation of ventricular myocytes in normal and failure guinea-pigs

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.