ATP inhibits the spontaneous contractility of atria in rats

Abstract

ATP is a multifunctional nucleotide. In recent years, strong evidence has accumulated that ATP may participate in intercellular signaling, where ATP acts as a cotransmitter. ATP participation in the regulation of physiological functions in the organism is carried out through specific purinoreceptors, which were found in many tissues of the organism, including the heart. The aim of our research was to study the role of ATP at different concentrations on the parameters of electrical activity and the contractility of the myocardium of the right atrium of rats with a preserved sinus node. The experiments were performed on the myocardium of the right atrium of rats with spontaneous activity. Isometric reduction and electrical activity of the drugs were recorded. ATP at the concentration of 10–8 M caused no significant changes in the parameters under study. ATP at the concentration of 10–7 M caused two-phase changes in the amplitude-time parameters of myocardial contractility and electrical activity of the right atrium myocardium. In the first minutes of the experiment, ATP caused an increase in the frequency and strength of myocardium contraction and the duration of the action potential at the level of 20, 50, and 90% repolarization. By the 15th minute, the studied parameters were restored. ATP at the concentration of 10–6 M caused a negative inotropic and chronotropic effect, through the activation of adenosine receptors.

Keywords

• purinoreceptors
• atp
• action potential
• myocardial contractility