LOCALIZATION OF ALPHA-1,2,3-SUBUNIT ISOFORMS OF NA,K-ATPASE IN CULTURED NEONATAL AND ADULT-RAT MYOCARDIUM - THE IMMUNOFLUORESCENCE AND IMMUNOCYTOCHEMICAL STUDY

By indirect immunofluorescence and preembedding peroxidase-diaminobenz idine technique the localization of polyclonal and monoclonal antibodi es against alpha 1, alpha 2 and alpha 3 isoforms of the Na,K-ATPase we re studied in rat myocardium. The alpha 1-subunit was identified predo minantly on sarcolemma of cultured myocytes, neonatal, as well as adul t cardiocytes. The alpha 2 signal was localized around nuclei of cultu red cardiocytes, very weak signals were seen in neonatal and more inte nse signal, were dispersed throughout the adult myocytes. The alpha 3- subunit immunoreactivity was weak and localized in cell processes conn ecting individual cultured cells, on sarcolemma and intercalated discs of neonatal cells and very weak in adult working myocytes. Cytochemic ally demonstrated ouabain resistant Na,K-ATPase localized in junctiona l sarcoplasmic reticulum may represent al isoenzyme which is directly involved in modulation of action potential fluxes.