نقش جريان پتاسيمي اصلاحي، تنظيمي سريع IKR بر فعاليت خود به خودي (تنظيمي) گره سينوسي - دهليزي و دهليزي - بطني قلب موش

The Role of Rapid Delayed Rectifier K+Current on Pacemaker Activity of Mouse Sinoatrial And Atrioventricular Node

Introduction: In the heart cells, rapid delayed rectifier K+current is one of the important currents for action potential repolarization phase. Rapid delayed rectifier K+current is blocked by low concentration of E-4031. The aim of this research was to compare the effect of E- 4031 blocker on pacemaker activity of sinoatrial node (SAN) and atrioventricular node (AVN) of mouse heart. Materials & methodes: The pacemaker activity of distinct intact SAN and AVN by two separate metal microelectrodes that contact the endothelial surface of nodes, was recorded before and during IjiM E- Accepted: 25 May, 2008) 4031 and cycle length (CL) was measured. Findings: 1 jiM E-4031 increased CL on SAN preparations by 67.6+12.5% and on AVN preparations by 28+3.5 %. These changes were significants in two nodes. Conclusion: It is passible to conclude that 1) the rapid delayed rectifier K+current was present in two nodes 2) the effect of E-4031 on CL of two nodes was different.