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Iu I Shcherbin

Publications and source records attributed to Iu I Shcherbin.

14 recordsLinked to original sources
PubMed2004

[Amplitude and frequency characteristics of sympathetic nerve discharge in normotensive rats].

Electrical discharges in the cervical sympathetic trunk and arterial blood pressure were recorded in chloralose-anaesthetized Wistar rats. Some experiments were performed in rats with impaired baroreceptor reflex. The efferent electrical activity was analysed in amplitude and frequency domain. It has been shown that arterial and cardio-pulmonary mechanoreceptors do not affect magnitude of the electrical activity. However, arterial and cardio-pulmonary baroreceptor reflex arc seems to be involved in frequency modulation of the efferent sympathetic activity.

Anesthetics↗
PubMed2003

[Comparison of somatosympathetic reflex in normotensive and spontaneously hypertensive rats].

In chloralose anaesthetized and paralyzed normotensive (Wistar, Wistar--Kyoto) and spontaneously hypertensive rats (SHR), a somatosympathetic reflex in the cervical sympathetic trunk elicited by a single electrical shock to forelimb afferent fibres in the median nerve was recorded. It has been shown that the elicited response of SHR is similar to the response of normotensive rats. Amplitude of somatosympathetic reflex in SHR is larger than that of somatosympathetic reflex in normotensive animals. It is supposed that somatosympathetic reflex in hypertensive and normotensive rats is formed in the same way. However, reflex excitability of sympathetic nervous system in SHR is greater.

Afferent Pathways↗
PubMed2000

[Study of tonic and evoked electrical activity in efferent fibers of the sympathetic nerve in white rats].

In anaesthetised Wistar rats, electrical sympathetic activity and a somatosympathetic reflex in the cervical sympathetic trunk elicited by a single electrical shock to forelimb or hindlimb afferent nerves, were recorded. The spontaneous activity was shown to conform with the pulse and respiratory waves of arterial pressure. Somatosympathetic reflex consists of early and late discharges evoked by somatic myelinated afferent fibres stimulation, and C-response elicited by stimulation of unmyelinated afferent fibres in spinal nerves.

Animals↗
PubMed1999

[Arterial mechanoreceptor reflex as a factor for execution of hypertensive responses to disturbing effects].

It has been shown in experiments on conscious cats and rats that arterial mechanoreceptor reflex is inhibited during averse emotional influence, and the changed reflex is a cause of elevation in arterial pressure. In one's turn the hypertension contributes to entry of blood plasma norepinephrine into brain and in this way increases the arterial baroreceptor reflex after the emotional influence is stopped. The augmentation of baroreflex promotes restoration of homeostasis after cessation of the stress situation.

Animals↗
PubMed1996

[The possible mechanism of the noradrenaline enhancement of the arterial baroreceptor reflex].

In anaesthetized cats intravenous infusion of norepinephrine induced the increase in arterial pressure and suppression of renal nerve electrical activity. The latter followed the infusion was stopped and arterial pressure returned toward control. The baroreflex suppression of sympathetic activity associated with norepinephrine increased in the case of preliminary mechanical damage to blood-brain barrier. Duration and intensity of the sympathetic activity suppression following norepinephrine infusion depended on the magnitude of hypertensive reaction and the rate of elevating in arterial pressure under the action of norepinephrine. Norepinephrine at the similar concentrations did not depress sympathetic activity if the arterial pressure was stabilized on the resting level. These data support the supposition that the elevation of arterial pressure due to norepinephrine infusion increases the ability of catecholamine to enter brain and in this way activates the central limb of arterial baroreceptor reflex.

Adrenergic alpha-Agonists↗
PubMed1991

[An analysis of the mechanisms enhancing arterial baroreceptor reflexes during noradrenaline infusion].

In cats-recipients with cut vagosympathetic trunks and hemodynamically isolated carotid sinuses, the latters were perfused with the blood from a cat donor. Noradrenaline infusion did not change the electrical activity of the renal nerve and induced an inhibition of the activity in high perfusion pressure. Noradrenaline seems to induce a short-term enhancement of arterial baroreflexes and to potentiate the effect on the central link of the reflex arch.

Animals↗
PubMed1990

[The participation of arterial baroreceptor reflexes in the prolonged inhibition of the electrical activity of the sympathetic nerves].

In immobilised male cats, arterial and venous pressure, heart rate and electrical activity of the renal nerve were recorded during i.v. infusion of noradrenaline at a constant initial level of arterial and venous pressure. The electrical activity of the renal nerve was inhibited and the heart rate decelerated, the obviousness of these effects increasing with acceleration of the infusion rate. The bradycardia was transient in anesthesia. The section of both vago-sympathetic trunks prevented the bradycardia and weakened the inhibition of the renal nerve activity. Additional denervation of both carotid sinuses eliminated the inhibiting effect of noradrenaline. Possible mechanisms of the noradrenaline effects are discussed.

Afferent Pathways↗
PubMed1988

[Analysis of compensatory mechanisms of arterial hypertension in norepinephrine infusion].

The NA infusion induced a raise in the AP, inhibition of sympathetic vasomotor activity and a drop in the heart rate in alert male cats. The hypertensive effect of the NA was weakening during first 90 min of the infusion, a complete inhibition of sympathetic activity persisted during the whole period of infusion as well as a decrease in the heart rate, in anesthetized cats. After deafferentation, the markedness of the arterial hypertension weakening decreased and the effect of the infusion on sympathetic activity and heart rate was abolished. Administration of pentamine during the infusion did not affect the AP in anesthetized cats, increased it in alert animals and decreased the AP in deafferented cats. The organism seems to have no humoral mechanisms of compensation of arterial hypertension induced with the 3-hr infusion of noradrenaline.

Animals↗
PubMed1986

[Role of afferentation from mechanoreceptors of the aortic arch and carotid sinuses in the long-term control of sympathetic tone].

In anesthetized cats, the enhancement of sympathetic activity and increase of the blood pressure in exclusion of afferents (section of vagosympathetic trunks and clamping of common carotid arteries) as well as the disappearance of the activity in enhanced afferentation, were shown to be transient and to disappear within a few minutes-scores of minutes in spite of the going on deafferentation or enhancement of afferentation. The afferent influences from the arterial baroreceptors seem to have no major significance for the long-term control of sympathetic tone.

Animals↗
PubMed1985

[Hypothalamic modulation of baroreceptor inhibition of the electrical activity in the renal nerve].

Changes in the renal nerve sympathetic activity in response to electrical stimulation of posterior hypothalamus and vago-aortic nerve were studied in acute experiments on cats. It was shown that stimulation of certain points in hypothalamus defence area led to the suppression of baroreceptor reflex-mediated inhibition of the renal nerve sympathetic activity. Chloralosa depressed hypothalamic modulation of baroreceptor reflexes.

Animals↗
PubMed1984

[Comparative study of baroreceptor reflexes in cats and rats].

The sensitivity of baroreceptor reflexes, the intensity of heart rate changes, and the electrical activity of renal nerve were compared in acute and chronic experiments with changing activity of arterial baroreceptor afferents in rats and cats. Activation of the baroreceptor afferents was due to blood pressure elevations induced with phenylephrine, deceleration of electrical activity of renal nerve was induced by baroreceptor deafferentation. The sensitivity of baroreceptor reflexes, the absolute and relative acceleration of heart rate after baroreceptor deafferentation, as well as the intensity of renal nerve activity suppression were considerably higher in cats as compared with rats.

Animals↗
PubMedDate not supplied

[Study of the central and peripheral mechanisms in enhancement of arterial baroreflex in cats during noradrenaline infusion].

An increased suppression of electrical activity of the cardiac inferior nerve by the baroreflex during norepinephrine infusion can be eliminated by a preliminary infusion of monoamine. The data obtained corroborated our previous findings that an increase in arterial pressure due to norepinephrine infusion was essential for catecholamine increasing the baroreflex inhibition of electrical activity in sympathetic nerves.

Animals↗