【Objective】 To investigate the signal transduction pathway of β-adrenergic receptor (β-AR) regulating INCX in myocytes from infarcted rats. 【Methods】 Thirty adult Wistar rats were divided into two groups at random: the control group (n = 15) and the post-myocardial infarction (post-MI) group (n = 15). The chest of rats were opened and ligature were placed around the left anterior descending coronary artery. Rats in control group were sham-operated without coronary artery ligation. Myocytes were enzymatically disassociated by Langedorff perfusion. Whole cell-patch clamp recording technique was used to record INCX in specific pipette solution and superfusion according to specific holding potential and command potential program. 【Results】 In the control group and the post-MI group

treatment with forskolin increased inward INCX in ventricular myocytes by 108.9% and 70.3%(P < 0.05)

respectively. An inhibitory cAMP analog (Rp-cAMPS) and H89 attenuated the rise of INCX induced by salbutamol (a selective beta2-AR agonist)(P < 0.05); pertussis toxin enlarged the rise of INCX by 36.8% and 50.6%(P < 0.05)

respectively. 【Conclusion】 Beta -AR might regulate INCX through the pathway of Gi-cAMP-PKA.