Changes in nuclear volume of Purkinje cells in the cerebellum of the water frog (Rana Esculenta L.) in the annual cycle.

In sexually mature female and male Rana esculenta L. frogs directly from natural habitat, in six characteristic periods of their life cycle, nuclear volume in Purkinje cells of the cerebellum was determined. Nuclear volume in Purkinje cells changed distinctly in the course of the year. Nuclear volume was greatest in females in the breeding period (3rd decade of May), and in males in the middle of the period of active life (2nd decade of July). Nuclear volume was the smallest at the beginning of hibernation (3rd decade of October).