キンギョのX線照射により生じた黒色素胞に対するKイオンの果粒拡散効果

The responses of the melanophores induced by X-ray irradiation to K ion were examined in the scale of the goldfish, Carassius auratus. Melanin-containing cells, melanocytes, within 10 days after irradiation did not show any intracellular displacement of the pigment to isotonic KCl solution and also to 10^<-5> M adrenaline solution. During 2 to 3 weeks after irradiation, newly formed melanophores did not still induced concentration of the pigment granules to KCl solution, but they could respond with rapid concentration of the pigment to 10^<-5> M adrenaline solution. If the melanophores assuming such a responsibility were immersed in KCl solution on the way of recovery from the pigment concentration in physiological solution, which was caused by application of 10^<-5> M adrenaline solution for 5 min, the melanophores showed immediate dispersion of the pigment of a considerable extent, the pigment dispersion persisting during immersion of the solution of KCl. On return to physiological solution, the pigment became again concentrated to much the same degree as that in the physiological solution previous to the treatment. Isotonic NaCl solution did not induced such a rapid dispersion of the melanophore pigment. These results may confirm that K ion has a dispersing effect on the concentrated melanophore pigment by acting directly on the cells, because the melanophores in such a period may not yet receive the supplies of the nerves by which pigment movements within the melanopnores are regulated. In well developed melanophores in irradiated goldfish about a month after irradiation, KCl solution caused concentration of the pigment. Even when these melanophores were in an intermediate state of the pigment, which was induced previously by application of 10^<-5> M adrenaline solution, they responded with only pigment concentration to KCl solution. Thus, it is concluded that K ion possesses two actions on the intracellular movement of the melanophore pigment ; one is prgment concentration intermediating the stimulation of the nerve terminals and the other is dispersion of the pigment.