Objective: To elucidate the effect of neurotrophin p75 receptor (p75NTR)on transmural dispersion repolarization (TDR) of the layers of left ventricular myocytes in rabbits with myocardial infarction (MI).
Methods: Forty Japanese rabbits were divided into four groups (n = 10): (1) Sham group, (2) Heald myocardial infarction (HMI) group, (3) p75 NTR activation group, (4) p75 NTR inhibition group. Cardiomyocytes were isolated with enzyme digestion and the currents were recorded by whole-cell patch-clamp technique.
Results: Compared with those in the sham group, the duration of 90% action potential repolarization (APD90) and transmural dispersion repolarization of three layers of left ventricular myocytes were obviously raised (P < 0.05). But significant reduction was observed in p75NTR(-) group. Current densities of Ito and I(Ks, tail) in the p75NTR(+) group and HMI group were significantly reduced (P < 0.05), especially in mid myocytes. And no obvious changes were observed in p75NTR(-) group.
Conclusion: Activation of p75NTR(+) increases transmural dispersion repolarization, which may lead to the incidence of arrhythmia.