title: Heterogeneous expression of connexin 43 in the myocardium of rabbit right ventricular outflow tract.
abstract: The right ventricular outflow tract (RVOT) has been demonstrated as an important focus in idiopathic ventricular arrhythmias. However, the role of the gap junction in this region in arrhythmic events has not been fully investigated. The purpose of this study was to evaluate the expression and distribution of the gap junction protein connexin 43 (Cx43) in the myocardium of the RVOT area of normal adult rabbits. Tissue samples were obtained from 6 regions of normal rabbit heart, i.e. the left ventricle (LV) free wall, the LV papillary muscle, the RVOT free wall, and the RVOT septum which was subdivided into the RV side, the central layer, and the LV side. Immunohistochemical analysis was performed to investigate the characteristics of Cx43 distribution in the RVOT area. In the LV free wall and papillary muscle, Cx43 was abundantly, homogeneously, and approximately equally expressed in end-to-end- and side-to-side intercellular connections. In the free wall of the RVOT, Cx43 expression was poor compared to both these LV regions and side-to-side cell connections were predominant. Cx43 was as richly and homogeneously distributed in the central layer and LV side of the RVOT septum as in the two LV regions. However, in the RV side of the RVOT septum, its distribution was scant and an unstained area was noted. The heterogeneous expression of Cx43 in the RVOT area may serve as substrate for idiopathic ventricular arrhythmia.
authors.affiliation: Department of Cardiovascular Science, Division of Laboratory Medicine, Oita University Faculty of Medicine, 1-1 Idaigaoka, Hasama, Oita 879-5593, Japan.
authors.forename: Baiqing
authors.initials: B
authors.lastname: Ou
authors.forename: Mikiko
authors.initials: M
authors.lastname: Nakagawa
authors.forename: Munetaka
authors.initials: M
authors.lastname: Kajimoto
authors.forename: Seiki
authors.initials: S
authors.lastname: Nobe
authors.forename: Tatsuhiko
authors.initials: T
authors.lastname: Ooie
authors.forename: Masashi
authors.initials: M
authors.lastname: Ichinose
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Yonemochi
authors.forename: Noriaki
authors.initials: N
authors.lastname: Ono
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Shimada
authors.forename: Tetsunori
authors.initials: T
authors.lastname: Saikawa
mesh_terms: D000818:Animals; D018031:Connexin 43 / Q000032:analysis / Q000378:metabolism*; D004077:Digoxin / Q000494:pharmacology; D004562:Electrocardiography; D005260:Female; D017629:Gap Junctions / Q000502:physiology*; D006352:Heart Ventricles / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D009206:Myocardium / Q000276:immunology / Q000378:metabolism; D011817:Rabbits; D017180:Tachycardia, Ventricular / Q000378:metabolism*; D016276:Ventricular Function; D016278:Ventricular Function, Right / Q000502:physiology*
chemical_list: D018031:Connexin 43; D004077:Digoxin