[Sympathetic regulation of heart rhythm under the effect of delta sleep peptide and its deficiency]. / Simpaticheskaia reguliatsiia serdechnogo ritma pri deistvii peptida del'ta-sna i ego defitsite v organizme.

In acute experiments on 16 rabbits we've studied effects of delta-sleep peptide and its deficiency on the irritation of the stellate ganglion. It has been revealed, that peptide injection (60 nM/kg) produces lowered positive chronotropic effect and elongated response development during irritation of this ganglion. Administration of antiserum to delta-sleep peptide (T = 1:3000) causes opposite effect: enhances sympathetic response during irritation of the stellate ganglion. Thus, delta-sleep peptide promoted lowered sympathetic influences on the heart.

[The role of delta sleep-inducing peptide in the electric stability of the heart]. / Rol' peptida delta-sna v élektricheskoi stabil'nosti serdtsa.

An experimental study in 38 rabbits explored the effect of delta-sleep peptide and its deficiency on thresholds of ventricular fibrillation or its precursors. The delta-sleep peptide (60 nM/kg) was shown to increase electric stability of the heart by elevating the thresholds of ventricular fibrillation and its precursors (ventricular extrasystoles and paroxysmal ventricular tachysystoles). Systemic deficiency of this peptide (the administration of antiserum T = 1:2000--1:3000, at 1:60 dilution) was, on the contrary, associated with lower ventricular arrhythmia thresholds. Therefore, delta-sleep peptide is shown to possess antiarrhythmic activity which may account for its protective cardiac effect under emotional stress.

[Parasympathetic regulation of cardiac rhythm in delta sleep-inducing peptide deficiency]. / Parasimpaticheskaia reguliatsiia serdechnogo ritma v usloviiakh defitsita peptida del'ta-sna v organizme.

The effect of delta-sleep peptide (DSP) deficiency on the parasympathetic regulation of the heart rate was studied on 35 rabbits. It was established that the injection of an-serum (titer-1:2000-1:3000) leads to the attenuation of parasympathetic influences: heart rate increase in freely behaving animals and a decrease in negative chronotropic effect with direct vagus irritation. Antiserum, like DSP, administration causes practically no damage of the myocardial ultrastructure.