ABSTRACT
Objective To study the characteristic of ultra-rapid delayed rectifier-potassium channel K current (IKur) in rat isolated atrial myocytes using whole-cell patch clamp technique, and the effect of Ibulitide on rat isolated atrial myocytes. Methods Atrial myocytes of rats on an in vitro Langendorf perfusion system were obtained by double digestion (collagenase typeⅡ) method. Whole-cell patch-clamp recording technique was used to record IKur currents. The current-voltage (I-V) curves of K+currents of atrial myocytes were fitted. With filled Ibulitide (2μg/L, filled 3 minutes), IKur was recorded. Results The Results showed that IKur was activated rapidly, almost no lag,and deactivation slowly. This current was activated at about-20 mV, the peak current was present apparent voltage dependence. The peak current density was (2.01 ± 0.27) pA/pF. After filled with Ibulite, this current was no any changed activation. Ibulite decreased the peak current density from+30 mV to+50 mV,but no statistical significance. Conclusion The IKur of rats can activate rapidly with no delays and inactivate slowly. This current is ultra-rapid delayed rectify outside current,and obvious displays the characteristic of outward rectification of whole action potential duration. The 2 μg/L Ibulitide shows no statistical significance for this current.