^<60>Co-γ線で照射したキンギョCarassius auratusにおけるNaイオン排出量の変化と, その放射線死との関係について(予報)
スポンサーリンク
概要
- 論文の詳細を見る
It is well established in mammals that the whole body irradiation with higher doses of ionizing radiations causes increased Na^+ excretion in feces, which is possibly the primary cause of the acute radiation death of the animals (Bowers & Scott 1951, Curran et al. 1960). In lower vertebrates, however, there have been only a few reports on such phenomena. Van der Schueren and Bonte (1958) demonstrated that UV-irradiated frog skin shows disturbed permeability to electrolytes, and Na^+ is lost through the skin in the experimental animals. They have also proved that the administration of Na^+ elongates the survival time of irradiated frogs. The present author has made experiments on the net sodium loss of the irradiated and non-irradiated goldfish. The animals used were Japanese common goldfish (Wakin) weighing 3-5g, obtained from a dealer in Tokyo. Irradiations were carried out with γ-rays emitted from ^<60>Co. Conditions of irradiation are as follows; dose rate 213r/min., without filter, ten animals were irradiated at the same time in a plastic cylindrical vessel, 6cm in diameter and with water measuring 2cm in depth. After the irradiation, the animals were transferred in 500ml of deionized water, in which they had been kept for 15 days without change of water and food supply. Samples of 5ml water media were colledted on the different post-irradiation days. The loss of water by evaporation was made up by daily addition of comparable amount of deionized water. This procedure was carried out 3-4 hours before the sample collection. Concentrations of Na^+ and K^+ were determined with Hitachi flamephotometer. The results obtained are summarized as follows. 1. Irradiated goldfish with 5325r showed characteristic daily pattern of net Na^+ loss, which is quite different from that of the non-irradiated animals (Fig. 2). The irradiated fish lost much greater amount of Na^+ than the controls. The experimental animals died within 8-12 post-irradiation days after loss of 500-750μg of Na^+. The author provisionally calls this phenomenon as the "sodium reaction" of the irradiated goldfish. 2. Irradiation with 1065r did not result in a typical sodium reaction. (Fig. 1). 3. Dose range where the sodium reaction occured seems to be in accord with that of "10-day effect" in gold fish, i.e. the dose range which causes the death of the animals within 8-12 post-irradiation days (Egami & Etoh 1962, Egami et al. 1962). 4. Remarkable changes in the net K^+ excretion after irradiation were not observed. 5. Further tracer experiments suggest that destruction of the intestinal epithelium by radiation is not so serious in goldfish as to cause disturbed Na^+ transport (Fig. 3), and not essential for the sodium reactin. 6. Mechanical destruction of the skin by rubbing the animals with dry absorbent cotton, caused the increased net Na^+ loss in the experimental animals (Fig. 4). 7. Histopathology of the irradiated skin revealed that the animals showing the sodium reaction were suffering from the damages of their epidermin (Fig. 5). The tissues were fixed in Bouin's solution on 10th day after irradiation. These facts, taken together, seem to suggest that the primary cause of acute radiation death in goldfish is the abnormally increased Na^+ loss from the destructed skin. Further experimental investigations, however, especially those on Na^+ absorption capability of the gills, are requisite for the conclusive discussion.
- 社団法人日本動物学会の論文
- 1962-10-15
著者
関連論文
- 日本産イモリの脂肪体の内分泌的調節(実験形態・発生)
- マウス着床部位における局所的免疫反応の解析(発生学)
- キンギョのえら経由のナトリウム排出におよぼすX線照射の影響(実験形態)
- ^Coγ線被照射金魚におけるNa^+排泄量の変化について(発生・実験形態)
- γ線照射による脊椎動物の電解質行動の変化(生理・生化学)
- ^Co-γ線で照射したキンギョCarassius auratusにおけるNaイオン排出量の変化と, その放射線死との関係について(予報)
- キンギョとメダカにおけるX線被照射量と生存期間との関係