Diadenosine Polyphosphates Suppress the Effects of Sympathetic Nerve Stimulation in Rabbit Heart Pacemaker


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Resumo

The modulatory influence of diadenosine tetraphosphate (Ap4A) and diadenosine pentaphosphate (Ap5A) on the effect of intramural autonomic nerve stimulation in isolated rabbit sinoatrial node were examined. Electrical activity of the sinoatrial node was recorded intracellularly. Against the background of blockade of adrenergic effects with propranolol (3×10—6 M) or in preparations isolated 2 h after injection of reserpine (2 mg/kg), nerve stimulation induced short-term membrane hyperpolarization and diminished the sinus node firing rate. These phenomena were not affected by Ap4A or Ap5A (10—5 M). Under the action of atropine (3×10—6 M) that completely eliminated the cholinergic influences, nerve stimulation enhanced the sinus node firing rate by 17.30±3.45% from the initial rate. Both Ap4A and Ap5A moderated the stimulation-induced elevation of firing rate to 9.9±2.8 and 10.5±2.9%, respectively. The data suggest that diadenosine polyphosphates significantly modulate the sympathetic influences on the heart rhythm, but have no effect on the parasympathetic control over activity of sinoatrial node.

Sobre autores

D. Abramochkin

Department of Human and Animal Physiology, Faculty of Biology, M. V. Lomonosov Moscow State University; Department of Physiology, N. I. Pirogov Russian National Research Medical University, Ministry of Health of the Russian Federation

Autor responsável pela correspondência
Email: abram340@mail.ru
Rússia, Moscow; Moscow

K. Pustovit

Department of Human and Animal Physiology, Faculty of Biology, M. V. Lomonosov Moscow State University; Department of Physiology, N. I. Pirogov Russian National Research Medical University, Ministry of Health of the Russian Federation

Email: abram340@mail.ru
Rússia, Moscow; Moscow

V. Kuz’min

Department of Human and Animal Physiology, Faculty of Biology, M. V. Lomonosov Moscow State University; Department of Physiology, N. I. Pirogov Russian National Research Medical University, Ministry of Health of the Russian Federation

Email: abram340@mail.ru
Rússia, Moscow; Moscow


Declaração de direitos autorais © Springer Science+Business Media, LLC, 2017

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