Epilepsy Like Anomaly of Mice

Abstract

An epilepsy-like anomaly of mice was encountered in the course of investigations of spontaneous hydrocephalus of mice in November, 1954. When mice were thrown up gently about 10-15cm high on a board for several times, they fell down suddenly on the plate followd by violent convulsions (Photo. 1-3) . After about 5 minutes, they stood up and recovered completely. These convulsions occurred suddenly and recovered very rapidly. Neuro-physiologically, loss of wrightening reflex, tonic convulsion, clonic convulsion and locomotive movement were observed. Reproduction of the anomaly by inoculation of a brain emulsion from the mice into normal ones resulted all negative. Bacteriological and PPLO examinations were also negative. In histopathological examinations, no significant lesions were noted either in the brain or in the visceral organs.
On the contrary, the characters were transmitted to their offsprings by mating. Homogeneous mating indicated 100 per cent positive, over four generations. A certain time lag (about 7 weeks or more) was required for the occurrence of the anomaly. At present (1959, January), it has reached to 12 generations and 7 or 8 weeks are necessary for the occurrence after their birth.
It is evident that this anomaly was due to genetic background. From an experiment of outcross, these characters seemed to be transmitted dominantly, however, it is difficult to make any conclusion about genes at present. Sex and food seemed to have no influence upon the occurrence of the anomaly.
Finally, it was concluded that this anomaly of micee is a new character being different from any mutants which are known, or from augiogenic seizures in several points.