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Br J Pharmacol. 1988 August; 94(4): 1250–1256. | PMCID: PMC1854089 |
Inhibitory actions of amoxapine, a tricyclic antidepressant agent, on electrophysiological properties of mammalian isolated cardiac preparations. T. Kinugawa, H. Kotake, and H. Mashiba 1st Department of Internal Medicine, Tottori University, Yonago, Japan. Abstract 1. The electrophysiological effects of amoxapine were examined in guinea-pig isolated papillary muscles and rabbit sinoatrial nodes using a conventional microelectrode technique. 2. In papillary muscles, amoxapine above 10 microM caused a dose-dependent decrease in the maximum upstroke velocity (Vmax) of the action potential and in the action potential amplitude (APA), whereas the action potential duration at 90% repolarization (APD90) was significantly prolonged. For a decrease in Vmax, amoxapine produced a negative shift of the curve relating Vmax to the resting potential (Em) along the voltage axis to more negative membrane potentials. 3. Amoxapine also decreased Vmax and the overshoot potential of K+-depolarized slow action potentials of papillary muscle preparations. 4. In spontaneously beating sinoatrial node preparations, amoxapine above 3 microM reduced the heart rate, Vmax, APA and the slope of phase 4 depolarization in a dose-dependent manner. 5. It was concluded that amoxapine exerts inhibitory actions on fast- and slow-response fibres of the heart and these actions can be mainly explained by inhibition of both fast Na+ and slow Ca2+ channels. Full text Full text is available as a scanned copy of the original print version. Get a printable copy (PDF file) of the complete article (702K), or click on a page image below to browse page by page. Links to PubMed are also available for Selected References. These references are in PubMed. This may not be the complete list of references from this article. - Arita M, Kiyosue T, Aomine M, Imanishi S. Nature of "residual fast channel" dependent action potentials and slow conduction in guinea pig ventricular muscle and its modification by isoproterenol. Am J Cardiol. 1983 May 1;51(8):1433–1440. [PubMed]
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