Developmental changes of RNA, DNA, lipid, protein and glutamic acid decarboxylase of rat forebrain, anterior midbrain, posterior midbrain, and cerebellum

Abstract

The concentration of glutamic acid decarboxylase (/*moles of glutamic acid decarboxylated/hr/gm) was found higher in the anterior midbrain than in several other regions of the adult rat brain. It was the highest in the anterior colliculus.posterior midbrain showed that the four regions behaved as distinct organs as regards the deposition of structural constituents and the activity of glutamic acid decarboxylase. There was evidence of postnatal cell acquisition by the four regions. The rate of accretion of DNA, RNA, phospholipid, and protein was the highest in the cerebellum, but that of glutamic acid decarboxylase was highest in the forebrain during postnatal development. The results indicated that the average size of the cerebellar cell in the adult rat was smaller than that of the cell of the forebrain, anterior midbrain, and posterior midbrain. The phospholipid content compared to that of protein was higher in the posterior midbrain than in the other three brain regions.The presence of fully differentiated GABAergic neurons in the cerebellum appear by the end of the first postnatal week.A developmental study of the forebrain, cerebellum, anterior midbrain, and

Polyamines in the Developing Mouse Brain

“…In these tissues in the rat, ornithine decarboxylase activity and polyamine concentrations, particularly putrescine, are already declining at birth [26], This study extends and confirms a similar pattern for the development of the mouse brain polyamines. The later large increase in midbrain spermidine levels also supports pre vious evidence for a role of spermidine in myelin [4], In contrast to the other brain tissues exam ined, the cells of the rat cerebellum are pro duced during the first 3 weeks postnatally, with the major increase in cerebellar DNA occurring between 5 and 20 days after birth [2,26], Thymidine kinase activity and RNA concentration also peak during the second postnatal week [2,26]. The later decrease in DNA concentration and increase in protein concentration appear to be indicative of cel lular hypertrophy and maturation [2,26] and are similar to the changes reported here for the mouse cerebellum.…”