α-Adrenergic Receptor Blockade Inhibits Langendorff-Isolated Rat Heart Work.

We studied the effect of selective α-adrenergic receptor antagonist JP-1302 in concentrations of 10-10 M on inotropy, chronotropy, and coronary flow in the Langendorff-isolated rat heart. JP-1302 in all studied concentrations decreased the left-ventricular myocardium force contraction, HR, and coronary flow. The maximum inotropic, chronotropic, and vascular effects were observed when the antagonist was applied to the perfused solution in a concentration of 10 M.

Comparative Analysis of Cardiac Effects of α-Adrenoreceptor Stimulation In Vivo and Ex Vivo in Newborn Rats.

The study examined the effects of α-adrenoceptor stimulation on chronotropic function of Langendorff-perfused isolated heart ex vivo and on cardiac chronotropy in vivo in 7-day-old rats. α-Adrenergic receptor agonist A-61603 reduced heart chronotropy only in the whole organism. No chronotropic effects of selective stimulation of α-adrenergic receptors on isolated hearts were observed in ex vivo experiments.

Peculiar Aspects in Influence of α-Adrenoceptor Stimulation on Isolated Rat Heart.

The study examined the effect of α-adrenoceptor stimulation with methoxamine on chronotropic function of isolated heart perfused ex vivo according to Langendorff and cardiac chronotropy in vivo. Stimulation of α-adrenoceptors in isolated heart induced gradually developing bradycardia, which progressed during several minutes. Similar stimulation in vivo produced a short-term bradycardia probably terminated by the compensatory influences in the whole organism.

[Age-dependent peculiarities of the rat's heart cholinergic regulation].

In vitro and in vivo studies were performed to investigate the effects of M1-, M2-, M3-cholinoreceptors (M-AChR) blockade on the chronotropic and inotropic cardiac function in the rats of 1, 3, 6, 8 and 20 weeks old. These age groups were selected according to the development level of the autonomic regulation of the heart. It was found that the prior blockade of all three subtypes M-AChR did not prevent inhibitory effect of carbacholin on contractility of the atria and ventricles the animals of all studied age groups.

[Influence of hypokinezia of varying duration on the nitric oxide productions dynamics in rat's heart, spinal cord and liver].

By electron paramagnetic resonance method analyzed the production of nitric oxide (NO) in atrias and ventricles of the rat's heart, spinal cord and liver of rats after the contained in conditions of hypokinesia during 30, 60 and 90 days. It was discovered that the regime of hypokinesia leads to increase NO production in all the investigated tissues, and the largest increases were observed in 30-day hypokinesia.