Age-related differences in the response of blood stroke volume to stimulation of the sympathetic ganglion in rats with β-adrenoceptor blockade

Blood stroke volume in rats aging 21 and 56 days decreased during β-adrenoceptor blockade with propranolol, but increased again by the 15th minute after treatment. Suprathreshold stimulation of the stellate ganglion decreased the stroke volume and increased the heart rate in control animals. Electrical stimulation after β-adrenoceptor blockade was followed by a further decrease in stroke volume in young rats. In 100-day-old animals this parameter remained unchanged, while the cardiac output improved. © Springer Science+Business Media, Inc. 2004

Effect of electrical stimulation of right stellate ganglion on cardiac function in rats during postnatal ontogeny

In all examined age groups of rats, the threshold amplitude of stellate ganglion stimulation is higher for the positive chronotropic effect than for the inotropic effect. The stimulation produced a more pronounced effect on stroke volume than on heart rate

Role of P2X and P2Y receptors in rat myocardial contractility during ontogeny

Stable agonist of P2 receptors 2-methylthio-ATP and selective antagonists of P2X and P2Y receptors PPADS and reactive blue-2 were used for evaluation of the role of P2 receptors in positive contractile reaction of atrial and ventricular myocardium in rats. PPADS significantly moderated the effects of 2-methylthio-ATP in 14-, 21-, and 56-day-old rat pups, but potentiated them in 100-day-old rats. Under conditions of reactive blue-2 treatment, the positive effect of the agonist was preserved in the atria and ventricles in all age groups and was age-dependent. © Springer Science+Business Media, Inc. 2007

Effect of β-adrenoceptor blockade on cardiac activity in rats during postnatal ontogeny

Electrical stimulation of the right stellate ganglion produces a positive chronotropic effect in 21-, 56-, and 100-day-old rats. The response of the heart rate to suprathreshold stimulation increased from the 21st to 100th day. By contrast, during β-adrenoceptor blockade the heart rate response decreased. The data suggest that the role of β-adrenoceptor in the regulation of cardiac chronotropic function increased with age. © 2003 Plenum Publishing Corporation

Age- and sex-related characteristics and mechanisms of adaptations during the prepubertal and pubertal periods of development

Integrated study of the functional state of the sympathoadrenal system and the adrenal cortex in children of both sexes aged 10-15 years. The study was conducted on the basis of the daily adrenaline, noradrenaline, 17-ketosteroid, and 17-oxycorticosteroid excretion values, which allowed certain synchrony to be established in the manifestation of the activity of the transmitter link of the sympathoadrenal system and the adrenal cortex androgenic and glucocorticoid functions with age, during sexual maturation. The heterogeneous character of maturation was found in the sex groups: in girls at an age of 10 and 12 years and in the boys at an age of 14-15 years. Changes in the excretion of the hormones and hormone metabolites with different directions and rates in the age-sex groups were observed throughout the academic year. In 14- to 15-year-old boys, a sharp increase in the daily excretion of the glucocorticoid metabolites accompanied by a substantial decrease in the age-related noradrenaline excretion values and the sex hormone metabolite values at an age of 15 years was observed. In the girls, these values varied within the age range, which indicates a more perfect character of the neuroendocrine regulation of their physiological functions in the period of sexual maturation. © 2009 Pleiades Publishing, Ltd

Purinergic regulation of rat heart function in ontogeny

The effect of exogenous ATP and its analogs on heart function was studied in 14-100-day-old rats. Extracellular purines had a positive chronotropic effect on the heart. Intravenous administration of exogenous ATP and its stable analogs induced a dose-dependent increase in heart rate depending on animal age. The analysis of isometric contraction of myocardial strips demonstrated a dose-dependent positive inotropic effect of ATP. The family and subtype of the P2 receptors realizing the positive chronotropic and inotropic effects were identified using selective agonists and blockers. P2X receptors demonstrated the highest sensitivity during early postnatal ontogeny. The age-related pattern of the receptor response to exogenous purines indicated the heterochronic maturation of P2X and P2Y receptors in the myocardium. © 2008 MAIK Nauka

Effect of ATP and its analogs on contractility of rat myocardium during ontogeny

The effects of P2-receptor agonists on myocardial contractility were examined in rats aging 14-100 days. ATP and its stable analog 2-methylthio-ATP potentiated the contraction force of isolated myocardial strips in a dose-dependent manner. The agonist concentrations producing the positive inotropic effect increased from days 14 to 100 of life. The efficiency of extracellular purines depends on animal age: in 14-and 56-day rats the positive inotropic effects of ATP and 2-methylthio-ATP were similar, while in 100-day rats ATP produced more pronounced effect than 2-methylthio-ATP. © Springer Science+Business Media, Inc. 2007

Puberty changes of haemodynamics in boys-athletes

The article describes the results of haemodynamics studies in hockey players aged 11-15 with regard to the stages of sexual maturation and their comparison characteristics with indicators of the boys from control class who do physical activity in terms of comprehensive secondary school. It has been shown that systematic muscle exercises have dominant effect on functional state of cardiovascular system in athletes in the prepubertal and pubertal periods of the development of their organisms; it is observed invariably high stroke volume of blood and systolic arterial pressure; maximum frequency indices of heart beats, volume of blood per minute and diastolic arterial pressure are observed at the 1-st and 2-nd stages of puberty, and minimum - at the 3-d stage, as distinct from the children of control class, whose parameter data dynamics has opposite direction. It may indicate to stress character of physical overactivity by effect of which the adaptive responses of cardiovascular system predominate over puberty change of its functional activity

Adrenal Gland Hormones in Primary School Children

© 2015 Springer Science+Business Media New York It was found that in 8-9-year-old children, the hormonal part of the sympathoadrenal system more rapidly develops in boys, while the transmitter part develops more rapidly in girls. The androgenic and glucocorticoid function of the adrenal cortex matures earlier in girls. To the end of the school year, excretion of epinephrine and norepinephrine decreased, which attests to the development of fatigue

Inotropic effect of dopamine on rat heart during postnatal ontogeny

We studied the effect of dopamine in concentrations of 10-9, 10-8, 10-7, 10-6, and 10-5 M on contraction strength of isolated myocardial strips from the right atrium and right ventricle of rats aging 21, 42, 56, and 100 days. Dopamine in a concentration of 10-9 M had a positive inotropic effect in rats of various ages. Increasing the concentration of dopamine to 10-7- 10-5 M was accompanied by a negative inotropic effect on the heart. © 2013 Springer Science+Business Media New York