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Updated: Mar 13, 2026

Isolation of Human Atrial Myocytes for Simultaneous Measurements of Ca2+ Transients and Membrane Currents
Published on: July 3, 2013
Effect of ICa,L Blockade on Adrenergic Stimulation in Developing Heart
T L Zefirov1, A M Kuptsova2, R G Biktemirova2
1Department of Human Health Protection, Kazan (Volga Region) Federal University, Kazan, Russia. zefirovtl@mail.ru.
Abstract:
The effect of verapamil-induced blockade of L-type calcium ionic currents (ICa,L) on the action of non-selective adrenergic cardiac stimulation by norepinephrine was examined during different periods of early postnatal ontogeny. In 1-week-old rats, intravenous norepinephrine induced a short-term tachycardia both with and without preliminary injected verapamil. In 3-week-old rats, norepinephrine alone produced no chronotropic effect; in contrast, it induced a biphasic tachycardia in verapamil-treated rats. In 6- and 20-month-old rats, norepinephrine induced a short-term tachycardia, which could be prevented by verapamil. The age-related peculiarities of chronotropic action of non-selective adrenergic stimulation are indicative of the role of L-type calcium ionic channels in the development of sympathetic control over the heart.
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