Adrenoceptors in Dopaminergic Regulation of Rat Myocardial Contractility in Rats During Ontogeny.

The effects of different dopamine concentrations on contractility of myocardium with blocked α- or β-adrenoceptors were examined in vitro in 21- and 100-day old rats. In myocardial strips with blocked α-adrenoceptors, dopamine (10 M) increased the right atrial contractile force. By contrast, this neurotransmitter (10-10 M) reduced the contractile force of atrial and ventricular strips with blocked β-adrenoceptors.

[The impact of increased physical exertion on adrenal cortex state and puberty of the boys].

The research of the adrenal cortex (AC) functional state of 11-15-year-old boys-sportsmen, conducted on the basis of free and bound cortisol (Cf, C) daily excretion indicators, as well as their comparative characteristics with the test class boys revealed that the increased physical activities in the form of regular sport trainings have the overwhelming impact on the age dynamic of AC and puberty of the young sportsmen. It is shown that the Cfexcretion of the 12-14-year-old-sportsmen is characterized by the consistently high indices, and by age of 15 it is observed a significant decrease in the setting of high C values. In contrast to the boys that do not go in for sports and cortisol in urine of which is significantly lower (p < 0.

[Influence of the initial vegetative tone on the condition of haemodynamics of younger schoolboys].

The comparative analysis of the functional condition of cardiovascular system and their reaction to the local isometric exercise for the 7-8-year-old boys, who are practically healthy, and in relation ship with the initial tone of the vegetative nervous system is given in the article. By means of variation pulsometer analysis, as well as by means of tetrapolar breast rheography it is found that children with sympathetic influences on heart rate (67.00%-55.

[Human sympathoadrenal system and adrenal cortex in prepubertal and pubertal periods].

A complex study of the functional state of the sympathoadrenal system and adrenal cortex in 10-15-year-old children of both sexes was carried out using the indices of daily excretion of adrenaline, noradrenaline, 17-ketosteroids, and 17-hydroxycorticosteroids. A synchronism in the functional activity of the mediator component of the sympathoadrenal system as well as of the androgenic and glucocorticoid functions of the adrenal cortex was observed with age and during pubertal development of children. At the same time, heterochronic maturation was observed in the sex groups: in girls at the age of 10 and 12 years and in boys at the age of 14-15 years.