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V I Kucher

Publications and source records attributed to V I Kucher.

12 recordsLinked to original sources
PubMed2005

Formation of locomotor patterns in decerebrate cats in conditions of epidural stimulation of the spinal cord.

Acute experiments on decerebrate cats were performed to study the mechanism of formation of the locomotor pattern in conditions of epidural stimulation of the spinal cord. These studies showed that only segments L3-L5 contributed to generating the stepping pattern in the hindlimbs. At the optimum frequency (5-10 Hz) of stimulation of these segments, formation of electromyographic burst activity in the flexor muscles was mainly due to polysynaptic reflex responses with latencies of 80-110 msec. In the extensor muscles, this process involved the interaction of a monosynaptic reflex and polysynaptic activity. In epidural stimulation, the stepping pattern was specified by spinal structures, while peripheral feedback had modulatory influences.

Animals↗
PubMed2003

[Features of stepping pattern formation in decerebrated cats under epidural spinal cord stimulation].

The mechanisms of stepping pattern formation initiated by epidural spinal cord stimulation in decerebrated cats, were investigated. It is shown that the ability to produce the stepping pattern involve the L3-L5 segments. In flexor muscle, the formation of stepping pattern under optimal stimulation frequency (5-10 Hz) of these segments is provided by polysynaptic activity with the latency 80-110 ms. In extensor muscle, this process is realized through interaction of monosynaptic reflex and polysynaptic activity. The stepping pattern under epidural stimulation is determined by spinal structures with modulation influence of the peripheral feedback.

Animals↗
PubMed1987

[Effect of the natriuretic factor on the transport of electrolytes and energy metabolism in kidney cortex sections].

The peptide material of the 2nd and 3rd fractions of the natriuretic factor did not affect the passive sodium transport while inhibiting the active transport in slices of the rat kidney cortex. This inhibition was accompanied by a decrease of both the succinic dehydrase system and Na+, K+-activated ATPase activities in the slices. The natriuresis caused by the natriuretic factor seems to be due to the inhibition of the active sodium transport.

Animals↗
PubMedDate not supplied

[Mathematical model of the digestion process regulation and its computer presentation].

The article presents a mathematic model, which describes regulation of the digestion process. The simulation was based on data on mutual influence of the factors participating in digestion regulation, which were acquired from analysis of over 1200 sources of experimental observations on digestion in dogs published in Russia and abroad, and on own experimental studies. The simulation includes 67 factors and about 400 interactions observed between them. The computer implementation of this simulation demonstrated descriptive coincidence of patterns of the variables respective to the factors of the model with experimental research data; the coincidence was observed in individual patterns and in combined patterns, as well as in coordinated responses in time.

Animals↗
PubMedDate not supplied

[Mathematical modeling of the mechanisms of locomotory pattern formation under epidural spinal cord stimulation with consideration of peripheral feedback].

The mechanisms of nervous regulation of locomotory activity of the spinal cord and participation of afferent peripheral feedback from lower limb muscles in the formation of locomotory patterns were investigated. The set of electromyograms of lower-limb muscle groups recorded in experiments on mesencephalic cats with application of electric epidural stimulations of lumbar segments of the spinal cord is described by a nonlinear dynamic model constructed on the basis of the Van-der-Pol equation with the compelling member. The conditions of occurrence of the regime of self-oscillations were investigated depending on the parameters of external influence. A modified equation was proposed, which takes into account the role of the afferent feedback and delay between the beginning of stimulation and muscle reaction. The conformity of the mathematical model with experimental data was shown, which makes possible its use both for the description of the mechanism of locomotory pattern formation under epidural spinal cord stimulation and the choice of optimum stimulation conditions.

Animals↗
PubMedDate not supplied

[Isolation of fractions containing natriuretic hormone from blood plasma and their testing in in vivo and in vitro experiments].

Natriuretic hormone (NUH) was isolated from the canine arterial blood plasma by means of gel chromatography on sefadex G-25. The plasma was preliminarily deproteinized with trichloro-acetic acid and the supernatant layer was lyophilized. Five peptide fractions were obtained by means of spectrophotometry in UV spectrum at 280 microns. The 2nd and 3d fractions of this material had a natriuretic activity in experiments on rats. The same fractions inhibited short-circuit current and the frog skin potential, as well as the frog skin oxygen consumption. For the present it is unlikely to confirm that this natriuretic activity should be caused by one or different chemical substances due to inaccurate separation of the 2nd and 3d fractions. The methods of a study of short-circuit current and the frog skin potential as well as a polarographic study of the frog skin oxygen consumption can be used for NUH testing.

Animals↗