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Biomedical subjects

V M Moroz

Publications and source records attributed to V M Moroz.

At least 19 recordsLinked to original sources
PubMed2006

Dysfunction of ionic channels in cardiomyocyte sarcolemma and cardiac arrhythmias.

The arrhythmic effects of Na+ and Ca2+ intracellular imbalance were examined on rats with aconitine-induced cardiac arrhythmias. Under conditions of Na(+)-dependent arrhythmogenesis, blockade of Ca(2+)-channels with verapamil aggravated cardiac rhythm disturbances. Correction of ionic imbalance by intravenous injection of calcium preparations in aconitine-induced arrhythmia promoted recovery of stable sinus rhythm and decreased animal mortality. Intracellular imbalance of Na+ and Ca2+ ions can underlie the arrhythmogenic effects of antiarrhythmic drugs.

Animals↗
PubMed2006

Study of pathogenesis of ventricular arrhythmia in experimental rats by separation of sinus and ventricular substitutional rhythms.

Pathogenesis of cardiac arrhythmia was determined by EEC changes after ATP-induced complete atrioventricular block. The re-entry mechanism underlays extrasystoles with equal coupling intervals with complexes of ventricular substitution rhythms, which transformed into paroxysmal tachycardia with equal R-R intervals, ventricular flutter, and ventricular fibrillation. Ectopic automaticity was characterized by extrasystole unrelated to the complexes of substitutional rhythms, which was transformed into accelerated idioventricular rhythm and asystole. During trigger activity, the extrasystoles were associated with complexes of basic rhythm and transformed themselves into torsades de pointes and ventricular fibrillation.

Adenosine Triphosphate↗
PubMed2002

[The study and comparative evaluation of the actoprotective activity of ATF-LONG in experiment].

In the paper, results are reflected of a swimming test in 78 laboratory rats. ATF-LONG has been shown to be capable of augmenting the animals' powers of endurance during loading tests. The established dose-dependent actoprotective activity of ATF-LONG is superior to that of adenosine triphosphate, trimetasidine (preductal), and mildronate. Possible pharmacological mechanisms of its actoprotective activity are discussed. The authors come to the conclusion that performance capability gets improved under exposure to purine nucleotides.

Adenosine Triphosphate↗
PubMed1992

[Role of the frontal cortex in the organization of rapid ballistic movements of rats].

Rapid ballistic food-getting movement characteristics were studied in albino rats. After ablation of the second area of the frontal cortex contralaterally as to the preferred extremity the number of attempts increased and their duration with reorganization of the phase structure of movements decreased. The habit of food extraction was lost after bilateral ablation of the cortex. The obtained results have illustrated significance of the frontal cortex in formation and realization of moving programmes.

Animals↗
PubMed1984

Effects of lateralized reaching and cerebellar stimulation on unit activity of motor cortex and caudate nucleus in rats.

Rats trained to reach into a narrow tubular feeder for food were implanted with bipolar stimulation electrodes in the dentate nucleus (DNT) ipsilateral to the preferred forepaw. Unit activity was recorded in freely moving animals (N = 15) with capillary microelectrodes inserted with a head-mounted microdrive into the contralateral motor cortex and caudate nucleus. Single-pulse stimulation of the DNT, subthreshold for eliciting overt movement and for interfering with reaching, evoked in both structures short-lasting excitatory responses sometimes preceded by brief inhibition. Reach-triggered stimulation changed the perireach histograms of the motor cortex neurons (N = 46) not only by interference with the movement-related and stimulation-elicited activities in the poststimulus interval but also considerably prolonged the prereach excitation. The perireach histograms of caudate neurons (N = 50) were not changed by the reach-triggered DNT stimulation in the prereach or in the poststimulus interval, probably because the movement-related activity overrode the electrical perturbation. The results indicated that the impairment of reaching caused by DNT stimulation was due to disorganization of the neuronal activity patterns in the motor cortex rather than in the caudate nucleus. The earlier onset of movement-related excitation in the motor cortex during stimulus-triggering reaching reflects attempts to cope with the disturbance by predictive reorganization of the motor discharge.

Animals↗
PubMed1983

Caudate stimulation prolongs latency of acoustically and visually signalled reaching in rats.

Latencies of acoustically and visually signalled lateralized ballistic reaching were examined in rats with implanted electrodes in the caudate nuclei (Cd). Single pulse stimulation of Cd coinciding with CS onset increased the reach latency from 180 to 300 ms. Stimulation of Cd contralateral to the preferred forepaw was more disruptive than stimulation of ipsilateral Cd and the interference threshold was lower for Cd stimuli applied 100 ms after CS onset. Since reaching latencies were only moderately prolonged (by 85 ms) after electrolytic lesion of ipsilateral dentate nucleus. Cd stimulation does not only disrupt cerebellar preprogramming, but has a more general interfering effect.

Animals↗
PubMed1983

A telerecording analysis of reaching disruptions in rats after stimulation or lesion.

In the so-called "handedness" experiments rats learn to retrieve food pellets from a narrow tubular feeder preferentially with the left or right forepaw. Frame-by-frame analysis of videotape recordings showed that the stereotype movement consists of a fast forepaw extension (54 msec), followed by isolated finger flexion (46 msec) overlapping later with slow forelimb retraction (180 to 400 msec). Reach-triggered single pulse stimulation of contralateral caudate nucleus or ipsilateral dentate nucleus interfered with finger flexion and disorganized the time course of the movement. Electrolytic lesion of the ipsilateral dentate nucleus caused marked slowing of the extension (80 msec) and finger flexion (140 msec) phases of the movement. Videoanalysis confirms the ballistic character of the initial phase of the reaching movement.

Animals↗
PubMed1981

Reaching-related potentials in caudate nucleus and cerebellum of rats.

Electrical correlates of the lateralized reaching reaction was studied in rats with implanted electrodes. Averaged event-related potentials (ERPs) in the cerebellar dentate nucleus consisted of a negative wave coinciding with reach onset and followed 70 msec later by a positive deflection. The most prominent component of the more variable caudate ERPs was a negative wave culminating 60--120 msec after reach onset. The positive and negative ERP deflections corresponded to inhibitory and excitatory reactions respectively, at the single neuron level.

Action Potentials↗
PubMed1978

[Responses of cat cerebellar cortex neurons to stimulation of the caudate nucleus, globus pallidus and substantia nigra].

Impulsive responses (IR) of the Purkinje cells (PC) and other units of the cerebellar cortex in the paramedian lobules, lobulus simplex and tuber vermis were evoked by stimulation of nucleus caudatus (NC) in cats under chloraloze-nembutal narcosis. The phasic IR as simple discharges (due to mossy fibre activation) were exhibited mainly with a latency of 5-12 and 14-20 ms; a latency of the compound responses ) due to climbing fibre PC activation) was equal to 5-6, 9-22 ms and more. There were differences in rhythmic reproduction of the responses depending on their latency. The recruitment responses were found during a 4-6/s NC stimulation. There was an inhibitory pause as an obligatory component of the tonic neuronal responses. Reactions of the same types (phasic and tonic) as in the case of the NC stimulation, but differing in unit's quantitative distribution according to the latency appeared in the globus pallidus (GP) stimulation. The minimal latency was 4 ms. Recruitment was observed as well. The substantia nigra (SN) stimulation evoked PC responses, activated by the climbing fibres with a stable latency (8.5 +/- 0.3 ms). SN, GP, n. inferior olive as well as thalamic nuclei are considered to play a definite role in realizing caudate-cerebellar connections, both oligosynaptic and polysynaptic.

Animals↗
PubMed1976

[Antagonistic interrelationships between the staphylococci and Sarcina isolated from the upper respiratory tracts of virtually healthy persons].

The antagonistic activity of staphylococci isolated from the mucosa of the anterior parts of the nose of practically healthy persons was studied with respect to 102 strains of Sarcinia. Staphylococcus aureus had the most pronounced inhibitory effect on Sarcinia. No difference in the antagonistic activity of the staphylococci isolated from the carriers of the permanent and transitory types was found. However, Staphylococcus aureus isolated from the permanent carriers had a broader activity spectrum.

Antibiosis↗
PubMedDate not supplied

[The organization of instrumental food-procuring movements in rats].

The roles of the lateral hypothalamus, basolateral nucleus of the amygdalar complex, the second field of the frontal cortex, and ventromedial thalamic nucleus in organization of the fast ballistic food-procuring movements were studied in albino rats. Sequences of uni- and bilateral destruction of the brain structures were assessed by photorecording. Movement-related neuronal activity in these structures was recorded in freely moving animals. A specific involvement of each of the above listed structures in organization of food-procuring movements was shown. The lateral hypothalamus seems to participate in initiation of the motor program and its efficient realization, the basolateral amygdala appears to produce activatory, training, and stabilizing effects. The second field of the motor cortex leads in movement acquisition (i.e., in memorizing) and decision making about triggering the program. The idea about the relay role of the thalamic motor nucleus is supplemented by understanding of its more complex integrative function.

Amygdala↗
PubMedDate not supplied

[Role of the ventromedial nucleus of the rats thalamus in food-procuring movements].

The characteristics of ballistic food-procuring movements were studied in albino rats. After electrolytic destruction of ventromedial nucleus of thalamus (VM) of contralaterally preferred extremity the number of attempts and frequency of movements were determined to increase with a decrease of their duration. The restoration of parametres of movements took place during a week. A phase structure of movements also undergoes some modifications: in the case of invariance of initial ballistic components, conditioned by strict links of programme one-side switching off of VM tells on the following components, subject to correction. Re-teaching, requiring the modification of motor programme caused considerable difficulties in rats with switched off VM. The obtained results illustrate the significance of rats' VM in the formation and realization of motor programmes.

Animals↗