腺苷对离体豚鼠心房肌细胞动作电位与收缩力的脱敏与反跳

Effects of desensitization and rebound to adenosine on action potential and contractility in atrial cells in guinea-pigs

目的 :研究腺苷 (Adenosine,Ado)对离体豚鼠心房肌细胞动作电位时程 (Actionpotentialduration ,APD)及收缩力的脱敏与反跳。方法 :采用标准玻璃微电极细胞内记录动作电位和肌力换能器记录心肌收缩力的方法 ,观察了Ado(1、10、10 0 μmol·L-1对离体豚鼠心房肌细胞动作电位 (Actionpotential,AP)的影响及对APD、收缩力的脱敏与反跳。结果 :(1) 1、10、10 0 μmol·L-1Ado缩短心房肌细胞APD的变化率分别为 9.5 8± 1.40 %、13.80± 2 .2 6 %、2 4.80±3.19% ,(2 ) 1μmol·L-1Ado对心房肌细胞APD无脱敏 (P >0 .0 5 ) ,10 μmol·L-1Ado与 10 0 μmol·L-1Ado对心房肌细胞APD均有脱敏 ,脱敏持续时间分别为 1min和 5min(P <0 .0 5 ) ;(3) 10 μmol·L-1Ado对心房肌收缩力有明显的脱敏现象 ,与对照值相比 ,收缩力的减小由 31.40± 16 .0 4% (2min)变为 5 0 .6 0± 15 .87% (4min) ;(4 )当洗脱Ado后 ,出现收缩力的反跳现象 ,与正常值相比 ,1、10、10 0 μmol·L-1Ado增加收缩力分别为 12 .38± 7.5 0 %、19.2 0± 8.44 %、2 7.6 0± 13.44 %。结论 :Ado可缩短心房肌细胞APD ;Ado对心房肌APD有脱敏现象 ,且呈浓度依赖性和时间依赖性 ;

Objective:To investigate the effects of desensitization and rebound to adenosine(Ado)on action potential duration(APD)and contractility in guinea-pig atrial cells.Methods:Electrical activity was I min (P<0.05) and 5min (P<0.05)respetively.The desensitization of contractility of 10μmol·L\+\{-1\}Ado was recorded using standard intracellular mcroelectrode technique and contractility was recorded using force transducer.We studied the effects of adenosine on the action potential and desensitization of contractility and rebound of contractility.Results:The results showed action potential duration were shortened by 1?10?100μmol·L\+\{-1\}Ado,the ratios of shortened APD were 9.58±1.40%,13.80±2.26%,24.80±3.19%,respectively.1μmol·L\+\{-1\}Ado had no desensitization(P>0.05),but the time of desensitization of 10μmol·L\+\{-1\}Ado and 10μmol·L\+\{-1\}Ado was 1 min(P<0.05) and 5 min (P<0.05),repectively. The desensitization of contractility of 10μmol·L -1 Ado was obvious in atrial cells,the decrease of contractility was changed 31.40±16.04%(2min) into 50.60±15.87%(4min),compared with control.After washing out Ado,contractility was shown to rebound,the ratio of increase of contractility by 1?10?100μmol·L\+\{-1\}Ado were 12.38±7.50%?19.20±8.44%?27.60±13.44%?respectively.Conclusion:Ado could abbreviate APD in atrial cells,the desensitization of Ado on APD was characterized by concentration-dependent and time-dependent in atrial cells,and the desensitization of contractility of Ado was obvious and contractility was shown to rebound after washing out Ado.