[The characteristics of the alpha-adrenergic regulation of the cardiovascular system in middle-aged and elderly subjects]. / Osoblyvosti al'fa-adrenerhichnoï rehuliatsiï sertsevo-sudynnoï systemy u liudei pokhyloho i staroho viku.

97 practically healthy young adult, elderly and old people were examined to study the age-associated changes in alpha-adrenergic regulation of the cardiovascular system. The values of central and renal hemodynamics, systolic and diastolic cardiac functions, skin and bulbar microcirculation and arterial blood pressure were determined in dynamics after injection of the alpha-stimulator phenylephrine (0.15 mg/kg of body mass intramuscularly) or alpha-blocker prazosin (0.015 mg/kg of body mass orally). In old age alpha-adrenergic effects on the heart were found to decrease. In elderly and old people the changes of peripheric blood circulation prevail in the structure of hemodynamic shifts arising in stimulation and alpha-adrenergic receptors blockage.

[Analysis of the effect of the alpha 1-adrenostimulator mezaton on plasma renin activity in healthy people of varying age]. / Analiz vliianiia al'fa1-adrenostimuliatora mezatona na aktivnost' renina plazmy u zdorovykh liudei raznogo vozrasta.

30 healthy people aged 20-34, 60-74 and 75-89 (10 subjects in each group) were examined to study the changes in plasma renin activity (PRA), the sympathetic nervous system tone, indices of central and renal haemodynamics after intramuscular injections of alpha 1-adrenostimulator mezaton (phenylephrine) in dose of 0.15 mg/kg of body mass. The pharmacological activity of postsynaptic alpha 1-adrenoreceptors was found to induce more considerable and prolonged increase of PRA in older persons. The increase of PRA was reliably correlated with a decrease of renal blood flow indices and was combined with an increase of sympathetic tone. As to the authors' opinion a more pronounced constrictor response of afferent renal arterioles to alpha 1-adrenoreceptors activation of vessels is the cause of more considerable changes of PRA in older age groups.