Bezkorovaina H. Gender-specific differences in development of adrenaline-induced myocardial necrosis in a setting of light desynchronosis

This dissertation has established gender-specific differences in the degree of metabolic and structural alterations in ventricular myocardium, the pattern of effects exerted by autonomic nervous system on heart rhythm, the sensitivity of myocardial cholinergic receptors in development of adrenaline-induced myocardial necrosis in a setting of either light deprivation or permanent lighting, and the cardioprotective role of melatonin. In female rats, light deprivation (for 10 days) alleviated the damaging myocardial effect of adrenaline to a greater degree, which was due to a higher activity of antioxidant enzymes. In males, the development of adrenaline-induced myocardial necrosis in a setting of light deprivation caused a predominant activity of parasympathetic link of vegetative nervous system in a setting of increased sensitivity of cholinergic receptors, while in females the preservation of regulatory balance between the activities of both links of vegetative nervous system occurred with a facilitated release of acetylcholine from the presynaptic portion and with increased sensitivity of cardiac cholinergic receptors. Permanent lighting (500 lux) was found to facilitate implementation of toxic myocardial effects; this finding was more pronounced in males due to a more substantial inhibition of activity of enzymes in the antioxidant system. The lower degree of adrenaline-induced cardiac damage found under identical conditions in females was achieved through a more active involvement of cholinergic mechanisms in cardiac adaptation to damage. A substantial cardioprotective effect of melatonin has been demonstrated in an experimental model of adrenaline-induced myocardial necrosis in a setting of permanent lighting, a finding substantially more pronounced in females.