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The experiments on dogs showed that Latranum, a selective blocker of serotonin 5-HT3-receptors, has a moderate capacity to modify emetic reaction caused by dophamin-stimulating action of Apomorphinum. These results, taking in account of our preliminary experimental data obtained by a model of early radiation-induced emetic reactions, show that the high antiemetic effect of Latranum may affect another mechanisms of the initiation of early radiation-inducing vomiting which do not connect immediately with the chemoreceptor trigger zone.

The experiments on dogs exposed to 137Cs gamma quanta at doses of 8 and 20 Gy showed that Latranum, a selective blocker of serotonin 5-HT3-receptors, is a more efficient antiemetic than Dimetpramidum, a D2-dophamin lytic. This is suggested by fewer animals with emetic reaction or by less severe vomiting in case they have any. The results, taking account of earlier data obtained in the experiments on M. fascicularis monkeys, show that the antiemetic effect of the blocker of serotonin 5-HT3-receptors Latranum is not species-specific and equally well manifests itself in animals with different constitutions of the chemoreceptor trigger zone.

The DNA and RNA contents, RNA/DNA ratio, and spontaneous and latex-induced oxidant activity indices of the whole blood were studied in the nitroblue tetrazolium test of mono- and polymorphonuclear blood leucocytes of intact dogs after injection of lipopolysaccharide pyrogenal. Significant changes in the above parameters were revealed for radioresistant (survived) and radiosensitive (lost) animals exposed to a subsequent prolonged gamma irradiation with a lethal dose of 7.64 Gy (LD75/45). Peroral introduction of 30 mg/kg indometofen (an indole analog of tamoxifen), which is a potential radioprotector, to dogs increased the survival rates of the irradiated dogs up to 93% and aided in the adaptive biochemical changes in the nuclear cell compartment of blood to induce a radioresistant status of the organism.

It was shown that indomethaphen (IM) is capable of stimulation of the synthesis of DNA, RNA, and protein precursors in mice. The IM-induced elevated level of the ribonucleotide reductase activity and, hence, deoxyribonucleotide pool in the spleen at the moment of irradiation and during the early postradiation period provides for complete DNA repair. As a result, the damaging effect of ionizing irradiation is weakened. At later stages (2-20 days) IM activates protein and DNA synthesis leading to the recovery of the ribonucleotide reductase activity in the spleen, on increased content of Fe3(+)-transferrin, cytochrome-c-oxidase, and ferrosulfuric components of the mitochondrial electron transport chain, and increased potential of the detoxication system due to the elevated content of cytochrome P-450. IM stimulates ATP synthesis. Thus, IM enhances compensatory-restorative reactions of the cell systems, more pronounced in the spleen than in the liver.

The influence of NS-1539, a potential anti-irradiation agent and indole analogues of tamoxifen on the DNA repair synthesis in the bone marrow and lymphocytes of peripheral blood was studied. It was found that the DNA repair processes from damages caused by chemical mutagen N-nitroso-N-methylurea or physical factor UV-irradiation in the bone marrow cells after the NS-1539 protection of mice as well as in lymphocytes of peripheral blood of human donors were enhanced. The enhancing of DNA repair synthesis was seen not earlier than 18 hours after the NS-1539 injection to mice in vivo or when NS-1539 was added to lymphocyte suspension in vitro and observed up to the third day. This period of time coincides with the time of formation of radioresistance of organism under the influence of this agent as well as with the time of realization effects of steroid hormones on target cells.