- 作者: Vladislav S. Kuzmin, Ksenia B. Pustovit and Denis V. Abramochkin
- 作者服務機構: Department of Human and Animal Physiology, Lomonosov Moscow State University , Leninskie gory 1, building 12, Moscow 119991, Russia Department of Physiology, Pirogov Russian National Research Medical University , Ostrovitjanova 1, Moscow 117997, Russia
- 中文摘要: --
- 英文摘要:
Background
Recently, NAD+ has been considered as an essential factor, participating in nerve control of physiological functions and intercellular communication. NAD+ also has been supposed as endogenous activator of P1 and P2 purinoreceptors. Effects of extracellular NAD+ remain poorly investigated in cardiac tissue. This study aims to investigate the effects of extracellular NAD+ in different types of supraventricular and ventricular working myocardium from rat and their potential mechanisms.
Methods
The standard technique of sharp microelectrode action potential recording in cardiac multicellular preparations was used to study the effects of NAD+.
Results
Extracellular NAD+ induced significant changes in bioelectrical activity of left auricle (LA), right auricle (RA), pulmonary veins (PV) and right ventricular wall (RV) myocardial preparations. 10–100 μM NAD+ produced two opposite effects in LA and RA – quickly developing and transient prolongation of action potentials (AP) and delayed sustained AP shortening, which follows the initial positive effect. In PV and RV only AP shortening was observed in response to NAD+ application. In PV preparations AP shortening induced by NAD+ may be considered as a potential proarrhythmic effect. Revealed cardiotropic effects of NAD+ are likely to be mediated by P2 purine receptors, since P1 blocker DPCPX failed to affect them and P2 antagonist suramin abolished NAD + −induced alterations of electrical activity. P2X receptors may be responsible for NAD + −induced short-lasting AP prolongation, while P2Y receptors mediate persistent AP shortening. The latter effect is partially removed by PLC inhibitor U73122 showing the potential involvement of phosphoinositide signaling pathway in mediation of NAD+ cardiotropic effects.
Conclusions
Extracellular NAD+ is supposed to be a novel regulator of cardiac electrical activity. P2 receptors represent the main target of NAD+ at least in the rat heart. - 中文關鍵字: --
- 英文關鍵字: Heart, Rat, Action potential, NAD+, Purine receptors, Pulmonary veins