Objective To investigate the change in potassium channel in ventricular myocytes in vitro derived from diabetic rats and the effect of insulin and dichloroaectic acid(DCA). Methods The diabetic rat model was established by injection of streptozocin(STZ) peritoneally using male Sprague-Dawley rats with body weight 150-200 gram. Ventricular myocytes were isolated by enzymatic method and the whole-cell patch clamp technique was used to record the potassiumion currents. Results The I to density of ventricular myocytes in diabetic rats was significantly decreased compared with control rats[at+60 mV, 15.90?1.19 pA/pF (n=25) vs 28.55?0.97 pA/pF (n=12), P