摘要：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 recorded using standard intracellular microelectrode technique and contractility was recorded using. We studied the effects of adenosine on the action potential and desensitization of contractility and rebound of contractility. Results The results showed that action potential duration were shortened by 1,10, 100μ mol·L -1Ado, the ratio of shortened APD was ( 9.58± 1.40)%,(13.80±2.26)%,(24.80±3.19)%, respectively. 1 μ mol·L -1Ado had no desensitization ( P >0.05), but the time of desensitization of 10μ mol·L -1 Ado and 100μ mol·L -1 Ado was 1 minute( P <0.05) and 5 minutes( P < 0.05), respectively. The desensitization of contractility of 10?μ mol·L -1 Ado was obvious in atrial cells, the decrease of contractility of 10?μ mol·L -1 Ado was obvious in atrial cells, the decrease of contractility was changed from (31.4± 16.04)%(2 minutes) to (50.60±15.87)% (4 minutes), compared with control. After washing out Ado, contractility was shown to rebound, the ratio of increase of contractility by 1,10,100 μ mol·L -1 Ado was (12.38±7.50)%,(19.00± 8.14)% and (27.60±13.44)%, respectively. Conclusion Ado can abbreviate APD in atrial cells. The desensitization of Ado on APD is characterized by concentration-dependent and time-dependent in atrial cells, and the desensitization of contractility of Ado is obvious and contractility was shown to rebound after washing out Ado.
