TY - JOUR
T1 - Distribution of cardiac myosin isozymes in human conduction system. Immunohistochemical study using monoclonal antibodies
AU - Kuro-o, M.
AU - Tsuchimochi, H.
AU - Ueda, S.
AU - Takaku, F.
AU - Yazaki, Y.
PY - 1986
Y1 - 1986
N2 - To determine the presence and distribution of cardiac myosin isozymes in the human conduction system, we performed an immunohistochemical study using monoclonal antibodies CMA19 and HMC14, which are specific for myosin heavy chains of human atrial type (α-type) and ventricular type (β-type), respectively. Serial frozen sections of human hearts were obtained from autopsy samples and examined by indirect immunofluorescence. α-Type was found in all myofibers of sinus node and atrio-ventricular node, and in 55.2 ± 10.2% (mean ± SD, n = 5) of the myofibers of ventricular conduction tissue, which consists of the bundle of His, bundle branches, and the Purkinje network. In contrast, β-type was found in all myofibers of the atrio-ventricular node and ventricular conduction tissue, whereas almost all myofibers of the sinus node were unlabeled by HMC14. Although the number of ventricular myofibers labeled by CMA19 was small, the labeled myofibers were more numerous in the subepicardial region than in the subendocardial region. These findings show that the gene coding for α-type is expressed predominantly in specialized myocardium compared with the adjacent ordinary working myocardium.
AB - To determine the presence and distribution of cardiac myosin isozymes in the human conduction system, we performed an immunohistochemical study using monoclonal antibodies CMA19 and HMC14, which are specific for myosin heavy chains of human atrial type (α-type) and ventricular type (β-type), respectively. Serial frozen sections of human hearts were obtained from autopsy samples and examined by indirect immunofluorescence. α-Type was found in all myofibers of sinus node and atrio-ventricular node, and in 55.2 ± 10.2% (mean ± SD, n = 5) of the myofibers of ventricular conduction tissue, which consists of the bundle of His, bundle branches, and the Purkinje network. In contrast, β-type was found in all myofibers of the atrio-ventricular node and ventricular conduction tissue, whereas almost all myofibers of the sinus node were unlabeled by HMC14. Although the number of ventricular myofibers labeled by CMA19 was small, the labeled myofibers were more numerous in the subepicardial region than in the subendocardial region. These findings show that the gene coding for α-type is expressed predominantly in specialized myocardium compared with the adjacent ordinary working myocardium.
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U2 - 10.1172/JCI112310
DO - 10.1172/JCI112310
M3 - Article
C2 - 3511096
AN - SCOPUS:0022551628
SN - 0021-9738
VL - 77
SP - 340
EP - 347
JO - Journal of Clinical Investigation
JF - Journal of Clinical Investigation
IS - 2
ER -