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Biomedical subjects

I L Cherednik

Publications and source records attributed to I L Cherednik.

29 records · Page 2Linked to original sources
PubMed1997

[The connection between the structure and activity of enkephalins in the realization of their cardiotropic effects in cats].

In experiments on anesthetized cats the ability of natural enkephalins to affect baseline heart rate, the magnitude of vagal chronotropic effect and its components, inhibitory tonic and synchronizing, was compared with activity of synthetic analogs and short fragments of enkephalins. Substitutions of met-enkephalin structure in second and fifth positions did not modify its cardiac activity. When Tyr1 was removed the peptide lost ability to affect baseline heart rate and the magnitude of synchronizing vagal component, but modulatory influence on inhibitory tonic vagal effect still persisted. The conclusion has been made that various parts of amino acid chain of met-enkephalin have different significance in realization of cardiac effects evoked by this peptide.

Amino Acid Sequence↗
PubMed1995

[The dynamics of cardiac vagal sinus arrhythmia in cats under the action of met-enkephalin].

When stimulating the peripheral and of the right n. vagus in anesthetised cats, the sinus arrhythmia occurred in case the vagal bursts were beyond the limits of the controlled bradycardia range. I. v. administration of met-enkephaline suppressed the arrhythmia immediately but the latter reappeared within 15-20 minutes. The data obtained suggests a biphasic effect of met-enkephaline upon the vagal sinus arrhythmia.

Animals↗
PubMed1993

[The effect of synthetic enkephalin analogs on the vagus regulation of the heart rhythm].

I.v. administration of different enkephalin's analogues inhibited the vagal chronotropic effect in anesthetised cats. The effect was due to selective decrease of the tonic component amplitude whereas that of the synchronizing component either remained unchanged or increased. Different mechanisms seem to be responsible for realisation of the tonic and synchronizing vagal cardiac actions.

Animals↗
PubMed1993

[The action of met-enkephalin on sinus arrhythmia during the burst stimulation of the vagus nerve].

The ranges of the controlled bradycardia were obtained in experimental anaesthetized cats when peripheral cut end of the right vagus nerve was stimulated with bursts of impulses. Within the range each burst of impulses delivered on the vagus induced a single heart contraction and the heart synchronously reproduced any changes of vagal burst frequency. Sinus arrhythmia was observed when vagal burst frequency was beyond the limits of the controlled bradycardia range. Sinus arrhythmia discontinued or considerably decreased after met-enkephalin injection that contributed to the appearance of controlled bradycardia again. It is concluded that met-enkephalin increased the susceptibility of the heart to the series of vagal bursts arriving from the central nervous system.

Animals↗
PubMedDate not supplied

[The components of the negative chronotropic effect of the vagus nerve on the heart and a method for their definition].

Stimulation of the peripheral end of the right n.vagus led to synchronizing of the vagal and cardiac rhythms in anesthetised cats. The stimulation of the n.vagus beyond the synchronizing range resulted in the sinus arrhythmia. The negative chronotropic effect of the vagus nerve on the heart was shown to consist of tonic as well as synchronizing components. The latter component did not depend on the heart rate and may be expressed as a difference between the maximal and minimal cardiac cycle during the sinus arrhythmia. The tonic component was determined as a difference between the initial cardiac cycle and the minimal cardiac cycle during the sinus arrhythmia. It seems to be cumulative in nature and to depend on the heart rate.

Animals↗