Ahmed, A., El-Maraghy, N., El-Gharabawy, A., Mohamed, M., Nawrath, H. (1995). COMPARATIVE STUDY ON THE ELECTROPHYSIOLOGICAL EFFECTS OF MONENSIN ON ATRIAL AND VENTRICULAR MUSCLE PREPARATIONS OF GUINEA-PIG HEART. test, 4(2), 147-156. doi: 10.21608/zjps.1995.186268
Ahmed Ahmed; Nabila El-Maraghy; Atef El-Gharabawy; Mohamed Mohamed; Herman Nawrath. "COMPARATIVE STUDY ON THE ELECTROPHYSIOLOGICAL EFFECTS OF MONENSIN ON ATRIAL AND VENTRICULAR MUSCLE PREPARATIONS OF GUINEA-PIG HEART". test, 4, 2, 1995, 147-156. doi: 10.21608/zjps.1995.186268
Ahmed, A., El-Maraghy, N., El-Gharabawy, A., Mohamed, M., Nawrath, H. (1995). 'COMPARATIVE STUDY ON THE ELECTROPHYSIOLOGICAL EFFECTS OF MONENSIN ON ATRIAL AND VENTRICULAR MUSCLE PREPARATIONS OF GUINEA-PIG HEART', test, 4(2), pp. 147-156. doi: 10.21608/zjps.1995.186268
Ahmed, A., El-Maraghy, N., El-Gharabawy, A., Mohamed, M., Nawrath, H. COMPARATIVE STUDY ON THE ELECTROPHYSIOLOGICAL EFFECTS OF MONENSIN ON ATRIAL AND VENTRICULAR MUSCLE PREPARATIONS OF GUINEA-PIG HEART. test, 1995; 4(2): 147-156. doi: 10.21608/zjps.1995.186268

COMPARATIVE STUDY ON THE ELECTROPHYSIOLOGICAL EFFECTS OF MONENSIN ON ATRIAL AND VENTRICULAR MUSCLE PREPARATIONS OF GUINEA-PIG HEART

Zagazig Journal of Pharmaceutical Sciences
Article 23, Volume 4, Issue 2, December 1995, Pages 147-156    PDF (5.61 M)
Document Type: Original Article
DOI: 10.21608/zjps.1995.186268
Authors
Ahmed Ahmed* 1; Nabila El-Maraghy2; Atef El-Gharabawy3; Mohamed Mohamed1; Herman Nawrath4
1Department of Pharmacology, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt.
2Department of Pharmacology, Faculty of Pharmacy, Zagazig University, Egypt
3Dept. of Pharmacology, Faculty of Pharmacy, Zagazig University, Egypt
4Dept. of Pharmacology, Faculty of Medicine, University of Mainz-Germany
Abstract
The effects of monensin (10 µmol/L) alone and in presence of verapamil (3 µmol/L) or ouabuin (1 µmol/L) or glibenclamide (10 µmol/L) or BaCl2 separately were studied on the electrophysiological properties represented by force of contraction, duration of action potential, and membrane resting potential of isolated atrial and ventricular muscle of guinea –pig heart. Monensin induced a transient increase in the force of contraction of atrial and ventricular muscles. It caused a decrease in action potential duration of papillary muscle, this effect was reversed by glibenclamide. Monensin increased the action potential duration of atrial muscle in absence or presence of glibenclamide. In presence of ouabain monensin induced a significant depolarization of resting membrane potential in both atrial and ventricular muscles. Verapanil did not antagonize the effects monensin. Monensin induced an increase in Na+ a transient increase in Ca2+ and a decrease in K+ contents of atrial and ventricular tissues. From the data of the present work it could be concluded that, Na+ pumped out the cell by Na+/K+ pump was less in atria then in ventricles in presence of moninsin. Less consumption of intracellular ATP in ventricular cells than in atrial cells, thus the ATP of ventricular cells did not reach the critical concentration level which open ATP dependent K+ channels, The study also showed absence of Na+ dependent K+ channels in guinea-pig atria.
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