Effect of [I.sub.Ca,L] blockade on adrenergic stimulation in developing heart

The effect of verapamil-induced blockade of L-type calcium ionic currents ([I.sub.Ca,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-t...

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Bibliographic Details
Published in:Bulletin of experimental biology and medicine 2016-10, Vol.161 (6), p.746
Main Authors: Zefirov, T.L, Kuptsova, A.M, Biktemirova, R.G, Ziyatdinova, N.I, Zefirov, A.L
Format: Article
Language:English
Subjects:
Tachycardia
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Summary:The effect of verapamil-induced blockade of L-type calcium ionic currents ([I.sub.Ca,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. Key Words: adrenoreceptors; L-type [Ca.sup.2+] channels; chronotropy; ontogeny; heart
ISSN:0007-4888
DOI:10.1007/s10517-016-3500-5