The c Fos immunoreactivities in the developing and adult rat cerebella

c Fos immunoreactivities were studied by immunohistochemistry in the developing and adult rat cerebella. c Fos immunoreactivities were observed in purkinje cells early in postnatal development (P26 d) and reached a peak by P40-P60 d, followed by a decline in the 3-month-old adult. The granule cells revealed c Fos immunoreactivities by P26 d but declined until P50 d. Then c Fos immunoreactivities increased in the granule layer by P50-P60 d and decreased again in the adult. The deep nuclei showed c Fos immunoreactivities by P40 d and persisted in the adult. In spite of the difference in the patterns of location in c Fos immunoreactivities from the early postnatal period to adulthood, no decrease in the amount of c Fos immunoreactivity was evident from immunoblotting studies. Thus, it is concluded that c Fos immunoreactivities change from development to adult, but this does not affect the total amount of c Fos protein expression in the cerebellum.