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Experimental studies of chronic noise exposure in modern urban life testified about oxidative stress due to the corresponding hormones effects leading to accumulation of reactive oxygen species and endothelial dysfunction. This study aims to evaluate the protective effect of α2-adrenoblockers to modulate oxidative stress and corticosterone levels due to chronic noise exposure. To achieve this, we examined the effects of beditin (2-aminothiozolyl-1,4-benzodioxane) and mesedin (2-(2-methyl-amino-thiozolyl)-1,4-benzodioxane hydrochloride), along with changes in corticosterone, Ca2 + content, and morphological alterations in various tissues under noise-induced stress. Beyond this, detection of immune-reactivity and proliferation of Galarmin-containing cells in adrenals, and isolation of the total fractions of superoxide-producing associate from the rat liver under noise exposure and the beditin and mesedin actions on them were pertinent. Experiments were provided on the albino female rats divided into four groups: (1) control, (2) noise-exposed, (3) noise-exposed and beditin-injected (2 mg/kg, i.p.), and (4) noise-exposed and mesedin-injected (10 mg/kg, i.p.) animals. The noise exposure was of 91 dBA noise on 60 days with a daily duration of 8 h. For the first time, the total fractions of superoxide-containing associates were separated from the cell membranes of the rat liver tissue under the chronic noise stress conditions and the regulative effects of the α2-adrenoblockers. Increased 45Ca2+ and decreased corticosterone levels in the mentioned tissues, as well as dystrophic changes, were observed under the chronic noise exposure. Prominently, α2-adrenoblockers showed antioxidant effects, modulating pathological shifts of the noise-induced stress. [ABSTRACT FROM AUTHOR]

One of the reasons of the development of pathologies causing death is hypoxia. The purposes of this study were (1) to study some physiological and biochemical mechanisms of α2-adrenoblockers, which ensure the tissue resistance increase to hypoxia; (2) to offer new drugs contributing to the increase of tissues' stability towards the hypoxic affection; and (3) to submit new medications to surpass by their anti-hypoxic activity of those already used in modern medicine and have some advantages. The reactivity of postsynaptic vascular α2-adrenoceptors was determined on the damaged spinal cord expressed by the blood pressure increase in response to intravenous administration of azepexole that selectively binds to α2-adrenoceptors. Determination of the systemic hemodynamic values and the vascular resistance to the blood flow was performed by the method with plastic microspheres of marked isotopes. pO2 in the blood and the oxygen-transporting function were determined in a sample of 0.1 ml of blood in 30, 90, and 180 min after the α2-adrenoblockers' injections. It has been found that one of the major hemodynamic effects of mesedin and beditin was an improvement in cardiac output, as well as a prolonged increase in coronary blood flow and vasodilation of the heart vessels. Some anti-hypoxic mechanisms of the studied α2-adrenoblockers are an improvement of blood oxygen-transporting function followed by tissue oxygenation and the increased level of corticosterone and resistance to hypoxia. Revealing the mechanisms of action of the postsynaptic α2-adrenoceptors suggests that mesedin and beditin are potentially effective therapeutic means for many hypoxic conditions. [ABSTRACT FROM AUTHOR]