Role of P2X receptors in positive inotropic effect of rat myocardium during ontogeny

Abstract

Experiments with selective agonists and antagonists of purinoceptors allowed us to evaluate the subtype of P2X receptors. We showed that the myocardium of 14- 100-day-old rats contains functionally active P2X1 receptors. These receptors are involved in the realization of the positive inotropic effect of the atria and ventricles. Selective P2X1 receptor agonist beta,gamma-methylene-ATP induced a dose-dependent increase in the strength of atrial and ventricular contractions. P2X1 receptor antagonist TNP-ATP abolished the effect of the agonist in rats of all age groups.

Increased P2X7R expression in atrial cardiomyocytes of caveolin-1 deficient mice

“…The activation of P2 purinergic receptors causes an increased cardiac contractility in isolated mouse and rat hearts . Furthermore, functionally active P2X1 receptors are involved in the realization of the positive inotropic eVect of atria and ventricles (Zverev et al 2008). …”

Purinergic signalling and development of the autonomic nervous system

“…The response to P2X receptors is developmentally regulated, decreasing in the atria and increasing in the ventricles from postnatal day 14 to 100-day old animals. In 14 and 21 day old rats, β,γ-methylene ATP contracted both the atrial and ventricular myocardium, suggesting the involvement of either P2X 1 or P2X 2/3 receptors in the early postnatal inotropic positive response (Zverev et al, 2008). UTP concentrationdependently decreased myocardial contractions in the atria and ventricles of 7, 21 and 100-day old rats, possibly via P2Y 2 or P2Y 4 activation.…”