Radiation Effects on Nervous System and Roentgen-Pigmentation of Goldfish (Carassius auratus)

Abstract

Summary and Conclusions

Histological examination of the central nervous system of irradiated goldfish revealed: (1) Pronounced pathological changes in all instances, predominantly in the medulla oblongata and extending into the anterior horns of the spinal cord. (2) Alterations degree depending on the dose of roentgen rays. (3) Changes similar in character to those observed in the central nervous system of mammals. These consisted chiefly in demyelinization of fiber tracts, destruction of ganglion cells and a more or less pronounced gliosis.

The fact that these changes are most pronounced in the medulla oblongata, where the chromatomotoric nerve center is located, seems to support the assumption that destruction of this center may be the cause of roentgen pigmentation in the goldfish. In the light of these observations the caudal spread of melanophores can easily be understood as a descending degeneration of the pigmento-motoric nerve fibers. This seems to agree with the experiments of Von Frisch, 6 who produced in another fish (Phoxinus laevis L) pigmentation throughout the entire body after mechanical destruction of the pigmento-motoric center in the medulla oblongata. These observations, besides throwing some more light on the interesting interrelationship between central nervous system and pigmentation in fish, seem to be important as a further evidence for the equality in the effects of rays and mechanical stimuli on living matter. 7 , 8 Furthermore, the similarity of the character of the histological changes in the central nervous system after irradiation in goldfish and mammals seems to emphasize the suitability of the goldfish for purposes of experimental radiation therapy.