Dynamic Restructuring of the Myocardial Mitochondria in Response to Uridine Modulation of the Activity of Mitochondrial ATP-Dependent Potassium Channel under Conditions of Acute Hypoxic Hypoxia.

We studied the effects of in vivo modulation of activity of mitochondrial ATP-dependent potassium channel (mitoKATP) by uridine on the morphofunctional state of mitochondria in rat cardiomyocytes under conditions of acute hypoxia. Preinjection of uridine to animals reduced the number of structurally modified mitochondria, but had practically no effect on their morphogenesis after hypoxia. Uridine in vivo stimulated the formation of micromitochondria and their release into the cytoplasm. The number of "maternal" mitochondria containing three and more new micromitochondria, increased as well. The use of mitoKATP blocker 5-hydroxydecanoate in parallel with uridine abolished its protective effect, as it significantly inhibited the formation of micromitochondria in rat cardiomyocytes after acute hypoxic exposure.

[Myoglobin content and distribution in muscle tissues of Black Sea dolphins]. / Soderzhanie i raspredelenie mioglobina v myshechnoi tkani chernomorskikh del'finov

Myoglobin content is found to be higher in skeletal than in cardiac muscle of Tursiops truncatus and Phocaena phocaena and much higher than that in skeletal muscles of terrestrial mammals. According to the myoglobin content muscle fibres are devided into five types: red, white and three intermediate types. Deep muscles contain more red fibres and less intermediate fibres than superficial ones. White fibres compose almost one half of all fibres of the superficial skeletal muscles of the dolphins. The role of myoglobin distribution and higher content in oxygen supply of muscular tissue is discussed in relation to the peculiarities of dolphin breathing and blood circulation.