Regional Differential Expression of TREK-1 at Left Ventricle in Myocardial Infarction

Abstract

Background Altered membrane electrophysiology contributes to arrhythmias after myocardial infarction (MI). TREK-1 channel is essential in various physiological and pathological conditions through its regulation on resting membrane potential and voltage-dependent action potential duration. Objectives The aim of this study was to investigate changes in gene expression and electrophysiology of TREK-1 in the left ventricle in a MI model. Methods Fifty-five rats were divided into 5 groups: sham-operated group, 6 hours, 24 hours, 3 days, and 7 days post MI group ( n = 11 per group). TREK-1 messenger RNA (mRNA) expression level in the infarct region (IR) and infarct border region (IBR) were quantified by real-time polymerase chain reaction (PCR), and TREK-1 current density at the IBR was recorded with whole-cell patch-clamp technique. Results TREK-1 mRNA expression decreased significantly in both endocardial and epicardial cells in the infarct region after MI. Conversely, TREK-1 increased significantly in endocardial and epicardial cells from the IBR ( P < 0.01). Current density of TREK-1 at IBR increased significantly in both epicardial and endocardial cells after MI ( P < 0.01). Conclusions TREK-1 demonstrates specific changes in expression and electrophysiological function in left ventricle post MI. These results suggest that TREK-1 may participate in pathophysiologic alteration and electrical remodelling of left ventricular myocardium after MI, which may eventually lead to post-MI ventricular arrhythmias.