[Effect of neurotrophin p75 receptor activation on transmural dispersion repolarization in rabbits with myocardial infarction].
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.


CONCLUSIONS
Activation of p75NTR(+) increases transmural dispersion repolarization, which may lead to the incidence of arrhythmia.
Provincial Clinical Medicine College of Fujian Medical University, Fuzhou 350001, China.
Jian-Cheng
JC
Zhang
Mei-Yan
MY
Chen
Yang
Y
Li
Yi-Cheng
YC
Fu
Jin-Liao
JL
Gao
D000818:Animals; D001145:Arrhythmias, Cardiac / Q000503:physiopathology; D006352:Heart Ventricles / Q000503:physiopathology; D008564:Membrane Potentials; D009203:Myocardial Infarction / Q000503:physiopathology*; D032383:Myocytes, Cardiac / Q000502:physiology*; D018408:Patch-Clamp Techniques; D011817:Rabbits; D020800:Receptor, Nerve Growth Factor / Q000378:metabolism*
D020800:Receptor, Nerve Growth Factor