[CHANGES IN RHEOGRAPHIC INDICATORS OF SHIN IN ATHLETES OF DIFFERENT KINDS OF SPORTS].

We determined the changes of time, amplitude and derivatives of these indicators of rheovasograms of shin in sportsmen of youth age and high level of skills engaged in volleyball, athletics and wrestling with sports experience at least 3 years. We determined significant differences in the value of time, amplitude and derivatives of these indicators ofrheovazograms of shin in males youth age, depending on the impact of intense exercise. The volleyball players compared to youth who do not exercise, reliably large values of the overall tone of the arteries (11,2%), arteries of large diameter (8,2%), arteries of medium and small diameters (13,5%), time ascending part of rheovazograms (2%) and a slow passage (5,9%) and less dycrotycs index (17%), duration ofrheographic wave (3,7%), time descending part of rheovazograms (10%). The persons of control group had higher values of baseline impedance than wrestlers (9,9%) and athletes (13,7%) and all amplitude indicators rheograms of the shin than athletes (average 12-15%) and wrestlers (22-23%). The size and volume of blood flow to the arteries of the extremities adapted to the metabolic needs of the relevant muscles. In volleyball players compared to the athletes, a lower duration of rheographic wave (10%), time of downlink part of the rheograms (12,7%), the base impedance (17,2%), amplitude of the systolic wave (17%) and rapid blood filling (21%), all indicators tone of arteries (12,2-16,9%) and greater value of time of rising part of rheograms (3,5%) and slow blood filling (5,9%). Wrestlers compared to the athletes have a lower duration of rheographic wave (6,1%), time of downlink part of the rheograms (6,1%), the amplitude of the systolic wave (9,3%), compared with volleyball players set lower values of average speed of fast blood filling (15,6%), tone of arteries with different diameters (15-16,5%), all amplitude indicators (20-28%), time slow blood filling (9,7%), ascending parts rheogram (10,3%). Thus, the level ofphysical activity and especially muscle activity has a significant effect on the performance of regional blood flow.

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.

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.

[Investigation of c-fos expression and NADPH-diaphorase activity in the spine cord and brain in the development of the neck muscle weakness in rats].

The distribution of c-fos expression as a marker of neuronal activation and NADPH-diaphorase reactivity were examined in the cervical spinal cord, limbic structures and hypothalamus in anaesthetized rats after fatigue induced by intermittent high-rate (100 s(-1)) electrical stimulation of the dorsal neck muscles (mm. trapezius and splenius). In comparison to the control or sham-stimulated animals fatiguing stimulation induced significant increase in ipsilaterally in the C -C4 spinal segments and the contralateral central (Ce), medial (Me) nuclei, paraventricular nucleus of hypothalamus (Pa) and ventrolateral periaqueductal gray (VLPAG). In spinal cord the highest mean number of Fos-immunoreactive (Fos-ir) neurons per section was found in layers 1,4 and 5 (5.8 +/- 0.9, 13.1 +/- 0.9 and 11.1 +/- 0.7, P < 0.05) of the dorsal horn. The order of intensity of c-fos expression in different regions of the brain was as following sequence: Pa > VLPAG > Ce (447.7 +/- 23.5, 196.3 +/- 12.7, 104.6 +/- 12.3, respectively). About 50 % of double-labeled (Fos-ir and NADPH-diaphorase reactive) cells were found in Pa nucleus. Received data show that limbic structures, hypothalamus and VLPAG are involved in activation after neck muscle fatigue and might contribute to nociceptive processing and generation of the autonomic and affective components of the muscle pain.

Simulation of cardiac hypopolarization arrhythmias and evaluation of cardiomyocyte membrane hypopolarization in experimental animals.

A method for simulating cardiac hypopolarization arrhythmias was developed in order to study changes in cardiomyocyte membrane hypopolarization under the effects of antiarrhythmics and other drugs. The method is based on registration of K(+)-induced arrhythmias after intravenous injection of a minimum arrhythmogenic dose of 1.5% KCl over 2 sec. Atrioventricular and intraventricular blockades without arrhythmias are recorded in first-degree membrane hypopolarization. The same changes and cardiac arrhythmias are characteristic of second-degree hypopolarization. Third degree is associated with transitory cardioplegia, fourth degree with heart arrest and animal death.

[The study and comparative evaluation of the actoprotective activity of ATF-LONG in experiment]. / Izuchenie i sravnitel'naia otsenka aktoprotektornoi aktivnosti ATF-LONG v éksperimente.

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.

[The organization of instrumental food-procuring movements in rats]. / Organizatsiia instrumental'nykh pishchedobyvatel'nykh dvizhenii u krys.

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.

[The role of the basolateral nuclei of the rat amygdala in organizing rapid food-acquisition movements]. / Rol' bazolateral'nykh iader myhdalepodibnoho kompleksu shchuriv v orhanizatsiï shvydkykh ïzhodobuvnykh rukhiv.

The influence of electrolytic destruction of the basolateral nucleus of amygdala (BLA) on rapid food-getting movements was studied in albino rats. After one side destruction of the BLA, contralateral to the working forelimb it was found that the number of movements and their frequency decreased with an increase of their duration. After two side destruction of the BLA the number of movements increased with a decrease of their frequency. Duration of movements was unstable. After the BLA destruction (especially two side) all parameters were unstable both each day and during each experiment. Different level and character of the compensation after one- and two side destruction of the BLA was observed. The conclusion is made about the activating, stabilizing and training influences of the BLA on the rapid food-getting movements in rats.

[Role of the ventromedial nucleus of the rats thalamus in food-procuring movements]. / Rol ventromedialnogo iadra talamusa shchuriv v organizatsii izhodobuvnykh rukhiv.

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.

[Role of the frontal cortex in the organization of rapid ballistic movements of rats]. / Rol' frontal'noi kory v organizatsii bystrykh ballisticheskikh dvizhenii krys.

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.

[Laterality of food handling movements in rats]. / Lateralizatsiia pishchedobyvatel'nykh dvizhenii u krys.

Lateralization of motor food skills has been investigated on 77 adult white rats. The predominance for the left anterior extremity while carrying out food was found in 53.5% of rats, the right extremity--in 36.4% of rats. 10.3% of rats belonged to ambidexters. Prevalence of using left extremity was peculiar to the females as against the male ones. Three generations of left-handed rats obtained by crossing have been followed. Rats making use of the left extremity to take out food predominated in the second and third generates.

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.

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.

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.