[Effect of a postsynaptic alpha2-adrenoreceptor antagonist beditin on the rat resistance to seizure and Ca(+)-level in the brain tissue]. / Vliianie antagonista postsinapticheskikh alpha2-adrenoretseptorov beditina na ustoichivost' krys k sudorozhnym vozdeistviiam i soderzhanie Ca(2+) v tkani mozga.

In rats with a hemodynamic disorder caused by acute myocardial ischemia, preliminary administration of beditin in a dose of 25 mg/kg fully prevents a manifold increase in the level of 45Ca2+ in the cytosol of brain cells and leads to enhanced trapping and accumulation of labeled calcium in endoplasmic reticulum. With respect to calcium binding in endoplasmic reticulum, the action of beditin substantially differs from that of verapamil.

[Changes in the structure of DNA induced by sarcolysine in vivo and in vitro]. / Izmeneniia v strukture DNK, indutsiruemye sarkolizinom in vivo i in vitro.

Secondary structure and the rate of methylation of DNA, isolated from normal and malignant liver tissues (sarcoma 45) were studied in vivo and in vitro in presence of sarcolysine. The differential melting curve (DMC) in the DNA from malignant tissue was shifted, compared with that of the liver DNA, to the low temperature side and was characterized by appearance of an additional peak in the region of 50-60 degrees. A considerable increase in the level of methylation has been also noted in the DNA from malignant tissue. Sarcolysine caused a partial restoration of the DMC patterns and decreased by 20% the content of m5C in vivo; the DMC of the DNA from malignant tissue retained practically all its low-temperature features in vitro. The data obtained suggest that sarcolysine does not act directly on the DNA from malignant tissue but participates in an intermediate process, exhibiting a selective action on DNA.