Contribution of α-adrenoceptors to the contractility of the human myocardium in chronic coronary heart disease
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The inotropic response of isolated myocardial strips to α1-adrenoceptor stimulation was compared for patients with chronic coronary heart disease (CHD) and patients with WPW syndrome. The α1-adrenoceptors were stimulated with 1 × 10− M phenylephrine after blocking of the β-adrenoceptors with 3 × 10−1 M propranolol. The inotropic activity was recorded in the isometric mode. In the myocardium without signs of ischemic damage, stimulation of the α1-receptors caused a slowly developing single-phase positive inotropic response. The myocardium of the CHD patients was characterized by a three-phase response. The specific features of the inotropic response to α1-adrenoceptor stimulation in the CHD patients were assumed to be determined by changes in intracellular homeostasis of Ca2+. Electromechanical coupling in cardiac myocytes of CHD patients depends on Ca2+ deposited in the sarcoplasmic reticulum to a greater extent than coupling in the intact myocardium. An additional positive inotropic effect is possible upon exogenous calcium influx into cardiac myocytes.
KeywordsPropranolol Sarcoplasmic Reticulum Cardiac Myocytes Phenylephrine Electromechanical Coupling
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- 1.Afanas’ev, S.A., Lishmanov, Yu.B., Kondrat’ev, B.Yu., et al., Pharmacological Evidence of the Adrenergic Disturbance in Myocardium under the Conditions of Chronic Coronary Ischemia, Fiziol. Chel., 1997, vol. 23, no. 5, p. 58.Google Scholar
- 2.Osnes, J.B., Aass, H., and Skomedal, T., Adrenoceptors in Myocardial Regulation: Concomitant Contribution from Both α-and β-Adrenoceptor Stimulation to the Inotropic Response, Basic. Res. Cardiol., 1989, vol. 84, suppl., no. 1, p. 9.Google Scholar
- 3.Zarco, P. and Zarco, M.N., Biochemical Aspects of Cardioprotection, Medicographia, 1996, vol. 18, no. 2, p. 18.Google Scholar
- 4.Chazov, E.I., Controversial Issues of Chronic Heart Failure, Ter. Arkhiv, 1993, vol. 65, no. 9, p. 4.Google Scholar
- 5.Afanas’ev, S.A., Bogomaz, S.A., Alekseeva, E.D., et al., Changes of the Rhythmoinotropic Response of the Myocardium in Chronic Ischemia: Pathology or Adaptation?, Byull. Eksp. Biol. Med., 1994, no. 5, p. 457.Google Scholar
- 6.Otani, H., Otani, H., and Das, D.K., α1-Adrenoceptor-Mediated Phosphoinositide Breakdown and Inotropic Response in Rat Left Ventricular Papillary Muscles, Int. Bottler Parker, 1987, vol. 61, no. 11, p. 8.Google Scholar
- 7.Meerson, F.Z., Kopylov, Yu.N., and Baldenkov, G.N., α1-Desencitisation of the Heart during Adaptation to Stress, Fiziol. Zh., 1991, vol. 37, p. 3.Google Scholar
- 8.Kopylov, Yu.N. and Meerson, F.Z., Role of the Inositol Phosphate Cycle in Cardioprotective Adaptation to Periodical Hypoxia, Kardiologiya, 1992, vol. 32, nos. 9–10, p. 45.Google Scholar
- 9.Hawthorne, J.N. and Simmonds, S.H., Second Messengers Involved in the Muscarinic Control of the Heart: The Role of the Phosphoinositide Response, Mol. Cell. Biochem., 1989, vol. 89, no. 2, p. 187.Google Scholar
- 10.Mitchell, M.R., Powell, T., Terrer, D.A., and Twist, V.W., Electrical Activity and Contraction in Cells Isolated from Rat and Guinea-Pig Ventricular Muscle: A Comparative Study, J. Physiol., 1987, vol. 391, p. 527.Google Scholar
- 11.Kim, D. and Smith, T.W., Temporal Variation in Contractile State and [Ca++] in Isolated Adult Rat and Guinea Pig Cardiac Myocytes, in Biol. Isol. Adult Cardiac Myocytes, New York, 1988, p. 370.Google Scholar