Significant age-related peculiarities in the dynamics of stroke volume and parameters of variational pulsogram are revealed in bilaterally vagotomized in rats. Asymmetry in vagal influences on cardiac function appear during puberty. Right-sided vagotomy predominantly affects variability of the cardiac rhythm, while left-sided vagotomy mostly affects the force of heart contractions.
In intact rats vagal stimulation reduced heart rate, but had no effect on stroke volume. In sympathectomized animals this treatment decreased both the heart rate and stroke volume. Sympathectomized rats displayed higher sensitivity to vagal nerve stimulation compared to intact animals of the same age (except for rats aging 21 and 56 days).
We studied age-related peculiarities of changes in stroke volume, heart rate, and parameters of variational pulsogram after bilateral vagotomy in rats. Positive responses of stroke volume and heart rate to vagotomy appeared on postnatal week 4.
Right-sided vagotomy induced more rapid and pronounced changes in chronotropic indices, while left-sided vagotomy predominantly affected stroke volume. Right-sided, left-sided, and bilateral vagotomy induced similar changes in the variational pulsogram.Key Words: vagus nerve; heart; stroke volume," heart rhythm variability; rat Extracardiac regulation of the cardiac function is provided by sympathetic and parasympathetic influences which are considered as antagonistic, synergic, and compensatory [2,7,9]. Heart response to removal of the parasympathetic influences is species-specific [3,6]. In dogs, the right vagus nerve (VN) regulates the chronotropic, while the left VN controls the inotropic function of the heart [4]. It can be assumed that contraction force and heart rate are regulated by different mechanisms [5]. Therefore, it is of interest to study the tonic influence of contralateral VN on the inotropic and chronotropic heart functions. We studied the dynamics of stroke volume (SV) and parameters of a variational pulsogram after selective vagotomy in rats. MATERIALS AND METHODSExperiments were carried out on 20-week-old outbred albino rats (n=24) anesthetized with intraperitoneal urethan (800 mg/kg, 25% solution). Vagotomy was performed after fixation of the animal on the operation table and VN preparation. In group 1, the right and left VN were cut consecutively with a 60-min interval. In group 2, first the left and then the right VN were cut. In group 3 simultaneous bilateral vagotomy was performed. ECG and differential rheogram were recorded throughout the experiment to analyze heart activity. RESULTSRight-sided vagotomy caused a transient but significant increase in HR and cardiac output (CO) ( Table 1). The most pronounced changes in these indices were observed for the first 5 min. During this period SV showed no significant changes, but then SV and HR decreased.On the contrary, left-sided vagotomy significantly changed SV and only little affected HR (Table 2 ). SV decreased by 9% for the first minute, then increased, and after 5 min exceeded the initial value by 12.4%. It did not return to the baseline within 60 min, while HR decreased after 30 min (p<0.01). Both right-sided and left-sided vagotomy increased the mode amplitude and stress index and decreased the variation amplitude (Table 1, 2). At the same time, the dynamics of SV and HR were different which testifies to the specific effects of the right and left VN on contraction force and HR.Right-sided vagotomy performed after transsection of the left VN increased SV. The increase was most pronounced after 5 min, then SV returned to the initial level (Table 2). HR increased by 3.7% during the first 5 min, then decreased, and after 60 min was 11% below the initial value.
Aim. The article deals with the individualization of training for football players with diabetes. Materials and methods. The study was conducted during a one-year cycle on football players with diabetes in Moscow (Olympic Village-80) and at the Championship on mini-football for people with diabetes DiaEuro-2016 in Bosnia and Herzegovina. The study consisted of several stages. In the experiment, 22 football players with diabetes mellitus took part, who were allowed to regular trainings and mini-football competitions. The experimental group consisted of 11 players of the Russian national team. The control group included 11 players of the Serbia national team. The age of players was from 18 to 41 years. In the control and experimental groups, we conducted control tests to assess the speed, speed and strength qualities and special endurance. We recorded the matches to analyze the technique and tactics of each player. We also assessed glycated hemoglobin before and after the experiment in football players from the Russian national team. The pedagogical experiment covered the annual training cycle 2015-2016. It consisted of the preparatory period, divided into two stages (general preparation and special preparation), and competitive period. At the end of the experiment, we conducted tests to analyze the effect of the method used on football players with manifestation of diabetes mellitus. Results. The experimental program of sports training for football players with diabetes mellitus covered a one-year training cycle. At the beginning and at the end of the experiment, we assessed glycated hemoglobin (HbA1c) and insulin dosage in athletes with diabetes mellitus. To achieve HbA1c targets the athletes kept strictly to a diet and controlled blood sugar 8-10 times a day. At the end of the experiment, we registered that the majority of players (7 people) had perfect HbA1c (63.64 %), 4 players had optimal HbA1c (36.36 %), and nobody demonstrated sub compensation and decompensation. Conclusion. As a result of the implementation of our method in the preparatory period, players with diabetes improved their physical fitness indicators and the average index of glycated hemoglobin in comparison with the control group. The results obtained for the players of the Russian national team during competitions (control games and games of the Championship on mini-football for people with diabetes) prove the necessity of training individualization for athletes with diabetes participating in mini-football competitions.
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