Summary
Pressure-overloaded cardiac hypertrophy was induced by abdominal aortic constriction in 10-week-old male Wistar rats. 24–26 weeks after aortic constriction, the hearts were excised and a myocardial mechanical study was performed using isolated left ventricular papillary muscles. There was no significant difference in isometric developed tension (T) between sham-operated control and aortic constriction (AC) rats (control vs AC rats=2.9±0.6 vs 2.7±0.7 g/mm2). dT/dtmax of AC rats, on the other hand, was significantly lower than that of controls (controls vs AC rats=32.8±7.5 vs 26.3±6.1 g/mm2sp<0.05). Myocardial mechanical responses to isoproterenol (10−7 mol/l) were depressed in the group with aortic constriction compared with the control group (ΔT:18.5±6.7 vs 12.1±4.9%,p<0.05, ΔdT/dt: 25.2±6.2 vs 17.5±5.8%,p<0.02). Responses of the parameters to dibutyryl cyclic AMP (10−5 mol/l) were also smaller in the AC group than in the control group (ΔT: 18.0±5.6 vs 13.3±4.0%,p<0.05, ΔdT/dt: 20.4±6.9 vs 14.7±4.1%,p<0.05). Left ventricular myosin isoenzyme pattern, revealed by pyrophosphate gel electrophoresis, shifted towards VM-3 under pressure overload. The present study demonstrates that post-membrane processes may be mainly responsible for the decreased myocardial mechanical catecholamine responsiveness in pressure-overloaded cardiac hypertrophy.
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References
Ayobe MH, Tarazi RC (1983) Beta-receptors and contractile reserve in left ventricular hypertrophy. Hypertension 5 (suppl I):192–197
d'Albis A, Pantaloni C, Becher JJ (1979) An electrophoretic study of native myosin isoenzymes and of their subunits content. Eur J Biochem 99:261–272
Hoh JFY, McGrath PA, Hale PT (1978) Electrophoretic analysis of multiple forms of rat cardiac myosin: effects of hypophysectomy and thyroxine replacement. J Mol Cell Cardiol 10:1053–1076
Hoh JFY, Rossmanith GH (1983) Crossbridge dynamics in rat papillary muscles containing V1 and V3 isomyosins: effect of adrenaline. J Mol Cell Cardiol 15 (suppl 2):65 (abstr)
Imai S, Otorii T, Takeda K, Katano Y, Horii D (1974) Effects of cyclic AMP and dibutyryl cyclic AMP on the heart and coronary circulation. Jpn J Pharmacol 24:499–510
Jacob R, Rupp H, Ebrecht G, Gülch RW, Kissling G (1981) Chronic reactions of myocardium at the myofibrillar level. In: Nagano M, Seki I (eds) Cardiac structure and metabolism, Vol 4. Roppo (Tokyo), pp 1–28
Jacob R, Kissling G, Ebrecht G, Holubarsch C, Medugorac I, Rupp H (1983) Adaptive and pathological alterations in experimental cardiac hypertrophy. In: Chazov E, Saks V, Rona G (eds) Advances in myocardiology, Vol 4. Plenum Publishing Corporation, New York, pp 55–77
Kawamura M, Watari S, Nagata T, Iimura T, Ohkubo T, Kawanishi M, Nagano M (1983) Calcium binding and Na−Ca exchange in cardiac sarcolemma in experimental hypertension. In: Jacob R, Gülch RW, Kissling G (eds) Cardiac adaptation to hemodynamic overload, training and stress, Steinkopff, Darmstadt, pp 182–188
Lamers JMJ, Stinis JT (1979) Defective calcium pump in the sarcoplasmic reticulum of the hypertrophied rabbit heart. Life Sciences 24:2313–2320
Meerson FS (1976) Insufficiency of hypertrophied heart. Basic Res Cardiol 71:343–354
Rupp H, Jacob R (1982) Response of blood pressure and cardiac myosin polymorphism to swimming training in the spontaneously hypertensive rat. Can J Physiol Pharmacol 60:1098–1103
Takeda N, Dominiak P, Türck D, Rupp H, Jacob R (1985) The influence of endurance training on mechanical catecholamine responsiveness, β-adrenoceptor density and myosin isoenzyme pattern of rat ventricular myocardium. Basic Res Cardiol 80:88–99
Takeda N, Dominiak P, Türck D, Rupp H, Jacob R (1985) Myocardial catecholamine responsiveness of spontaneously hypertensive rats as influenced by swimming training. Basic Res Cardiol 80:384–391
Winegrad S, McClellan G, Tucker M, Lin LE (1983) Cyclic AMP regulation of myosin isoenzymes in mammalian cardiac muscle. J Gen Physiol 81:749–765
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Takeda, N., Ohkubo, T., Nakamura, I. et al. Mechanical catecholamine responsiveness and myosin isoenzyme pattern of pressure-overloaded rat ventricular myocardium. Basic Res Cardiol 82, 370–374 (1987). https://doi.org/10.1007/BF01907024
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DOI: https://doi.org/10.1007/BF01907024