Transmural Heterogeneity of the Action Potential Configuration in the Feline Left Ventricle

概要

論文の詳細を見る
There are M cells in the canine, rabbit, guinea pig, and human left ventricle (LV), but it is not known if they are present in the feline LV. Arterially perfused feline LV preparations were used for the recording of transmembrane action potentials from the epicardium (Epi), midmyocardium (M) and endomyocardium (Endo) under control conditions (n=12) and in the presence of IKs blocker (chromanol 293B : 10μmol/L, n=6) or Ik_r blocker (E-4031 : 2μmol/L, n=6). The steady-state action potential duration at 90% repolarization and cycle length (APD90/CL) relation was obtained and fitted by the hyperbolic function APD_<90>=CL/[(a×CL)+b]. In control, the shortest and longest action potential duration (APD) were observed in Epi and M, respectively, and the APD_<90>/CL-relation curve was steeper in the M or Endo than in the Epi. Chromanol 293B prolonged APD in Epi, but not in M or Endo, resulting in no significant difference of the APD_<90>/CL-relation curve among the 3 regions. E-4031 markedly, but homogeneously, prolonged APD in all regions, giving rise to decreased transmural dispersion of repolarization. In conclusion, there exists an M cell layer with a longer APD than the Epi and Endo layers and there is transmural electrical heterogeneity in the feline LV ; however, the response to IK_r blocker is different from that of the canine LV probably because of species differences in the IK_r and IK_s.
社団法人日本循環器学会の論文
2003-04-20