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Distribution of cardiac myosin isozymes in human and rat heart-immunohistochemical study using monoclonal antibodies
J Mol Cell Cardiol 18 (Supplement 3) (1986) LYSOSOMAL MECHANISMS IN MYOCARDIAL ISCHEMIA. K. Wildentha], J.R. Wakeland, B.A. Mayhew. Univ. Texas Health Science Center Dallas, Dallas, Texas, U.S.A. Roles for lysosomes and their constituent hydolytic enzyme have been postulated in (a) mediating ischemic damage, (b) mediating repair after ischemia, and/or (c) mediating post-necrotic degradation of dead cells. We have undertaken studies to explore each of these p o s s i b i l i t i e s . We have demonstrated that translocation of lysosomal enzymes into the cytosol occurs at or just before the time of ischemic cell death in a variety of conditions; this is compatible with (but does not prove) a role for lysosomes in mediating damage. We have also demonstrated major lysosomal changes in myocardial cells recovering from reversible damageafter hypoxia and substrate depletion, and shown that the normal recovery process is inhibited by ]ysosomotropic agents; this suggests involvement of lysosomes in repair in at least some models of ischemia. In recent studies, we have found that total protein degradation in necrotic myocardium is reduced by leupeptin and pepstatin. The degradation of myosin is not altered by lysosomal interventions in normal myocardium; however, myosin breakdown is relatively accelerated in post-ischemic necrosis, especially at acid pH, and this is inhibited by leupeptin and pepstatin. Thus, abnormally distributed lysosoma] proteinases appear to be activated after ischemia and may assist in the degradation of necrotic tissue. In summary, ischemia causes major ]ysosomal alterations which are compatible with functionally important roles for these organelles and their enzymes in ~schemic damage, recovery, and/or post-necrotic degradation.
ABOLITION BY B~-ADRENOCEPTOR (B~-H) BLOCKADE OF SUPERSENSITIVITY TO ISOPROTEBENOL (ISO) EVOKED IN BEATING CULTURED NEONATAL RAT HEART CELLS (CNRNC) BY L (+)-LACTATE (L) AND PYHUVATE (P)~ A. Wollenberger and G. Wallukat. Berlln-Buob, C~rman Dem. ~ep. We previously reported (JMCC 13, Suppl. I, 99, 1981) that rocker-CNHHC, distinguished by a low L content, became supersensitive to ISO by 4 orders of magnitude, as measured by their positive chronotroplc response (PCR), after having been treated for at least 45 mln wlth I mM P or 3 NM L but not D (-)-lactate. The8sensltlzatlon, unaffected by puromycln, was not expressed in the presence of 10- M (-)- propranolol, indicating par~iolpstlon of ~-R's in this phenomenon. We now can report that this effect of propranolol, e non-seleotlve B-blocker, is dupllcated, wltb~ut change in the control PCR, by the ~o-R selective antagonist ICI 118, 551 (3xi0- M), but not by the ~1-seleetlve antagonist aoebutelol. CGP-12177, a hydrophil~c non-seleotlve ~-R ligand blocked, at IO---M, the PCR and cAMP response to ISO 10-~M, which also is hydrophillc, but did not influence, in the absence of added L or P, the corresponding responses to the llpophilic B^-seleotlve agonlst olenbuterol (B~-selectlve also in our system). However, in P o~ L-treated cultures CGP-12177 abolished the PCR response to clenbuterol. Similar results were obtained using autoantlbodles against B_-R's isolated from the serum of allergic asthmatics. It may be inferred from these f~ndlngs that sensitization to ISO evoked in beating CNRHC by L and P involves B2-R's that after exposure of the cells to these metabolltes become accesslble to hydrophs ~-R llgands.
DISTRIBUTION OF CARDIAC MYOSIN ISOZYMES IN HUMAN AND RAT HEART-IMMUNOHISTOCHEMICAL STUDY USING MONOCLONAL ANTIBODIES. Y.Yazaki*, Y.Kira**, Y.Ito***, * The Third and 9 * Fourth Dept. of Int. Med., the University of Tokyo, *** Sanraku Hospital, Tokyo, Japan. Distribution of cardiac myosin isozymes(HC~ and H C ~ i n human and rat was studied mainly by immunohistochemical method using monoclonal antibodies. Human specimens were obtained by autopsy or during cardiac surgery. The effects of right ventricular (RV) pressure overload were also examined in pulmonary hypertensive rats induced by monocrotaline. In normal human heart, distributions of HCI(%) and HC~(%) were 100 and 20-60 in atrium (A), 40-50 and 100 in His-Purkinje system, 0~2 and 100 in subendocardial region of left ventricle (LV), 10-15 and 100 in subepicardial region of LV, respectively. In A of mitral failure, HCg decreased and HC~ increased with the correlation to the elevated mean pressures. The papillary muscles of LV in aortic failure showed the distribution change of increased HC~ along with decreased HCX with the elevation of LV systolic pressure. Furthermore, characteristics of peptide map and ATPase activity of HC~ and HC~ in A and V were very similar respectively. In addition, the existence of microheterogeneity in HC was suggested. In monocrotaline-induced pulmonary hypertensive rats, HC~ increased markedly not only in hypertrophied RV but also moderately in LV compared with control rats.
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ABOLITION BY B~-ADRENOCEPTOR (B~-H) BLOCKADE OF SUPERSENSITIVITY TO ISOPROTEBENOL (ISO) EVOKED IN BEATING CULTURED NEONATAL RAT HEART CELLS (CNRNC) BY L (+)-LACTATE (L) AND PYHUVATE (P)~ A. Wollenberger and G. Wallukat. Berlln-Buob, C~rman Dem. ~ep. We previously reported (JMCC 13, Suppl. I, 99, 1981) that rocker-CNHHC, distinguished by a low L content, became supersensitive to ISO by 4 orders of magnitude, as measured by their positive chronotroplc response (PCR), after having been treated for at least 45 mln wlth I mM P or 3 NM L but not D (-)-lactate. The8sensltlzatlon, unaffected by puromycln, was not expressed in the presence of 10- M (-)- propranolol, indicating par~iolpstlon of ~-R's in this phenomenon. We now can report that this effect of propranolol, e non-seleotlve B-blocker, is dupllcated, wltb~ut change in the control PCR, by the ~o-R selective antagonist ICI 118, 551 (3xi0- M), but not by the ~1-seleetlve antagonist aoebutelol. CGP-12177, a hydrophil~c non-seleotlve ~-R ligand blocked, at IO---M, the PCR and cAMP response to ISO 10-~M, which also is hydrophillc, but did not influence, in the absence of added L or P, the corresponding responses to the llpophilic B^-seleotlve agonlst olenbuterol (B~-selectlve also in our system). However, in P o~ L-treated cultures CGP-12177 abolished the PCR response to clenbuterol. Similar results were obtained using autoantlbodles against B_-R's isolated from the serum of allergic asthmatics. It may be inferred from these f~ndlngs that sensitization to ISO evoked in beating CNRHC by L and P involves B2-R's that after exposure of the cells to these metabolltes become accesslble to hydrophs ~-R llgands.
DISTRIBUTION OF CARDIAC MYOSIN ISOZYMES IN HUMAN AND RAT HEART-IMMUNOHISTOCHEMICAL STUDY USING MONOCLONAL ANTIBODIES. Y.Yazaki*, Y.Kira**, Y.Ito***, * The Third and 9 * Fourth Dept. of Int. Med., the University of Tokyo, *** Sanraku Hospital, Tokyo, Japan. Distribution of cardiac myosin isozymes(HC~ and H C ~ i n human and rat was studied mainly by immunohistochemical method using monoclonal antibodies. Human specimens were obtained by autopsy or during cardiac surgery. The effects of right ventricular (RV) pressure overload were also examined in pulmonary hypertensive rats induced by monocrotaline. In normal human heart, distributions of HCI(%) and HC~(%) were 100 and 20-60 in atrium (A), 40-50 and 100 in His-Purkinje system, 0~2 and 100 in subendocardial region of left ventricle (LV), 10-15 and 100 in subepicardial region of LV, respectively. In A of mitral failure, HCg decreased and HC~ increased with the correlation to the elevated mean pressures. The papillary muscles of LV in aortic failure showed the distribution change of increased HC~ along with decreased HCX with the elevation of LV systolic pressure. Furthermore, characteristics of peptide map and ATPase activity of HC~ and HC~ in A and V were very similar respectively. In addition, the existence of microheterogeneity in HC was suggested. In monocrotaline-induced pulmonary hypertensive rats, HC~ increased markedly not only in hypertrophied RV but also moderately in LV compared with control rats.
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