DNA synthesis in the Purkinje neurons.

(3H) Thymidine is incorporated into some cerebellar Purkinje cells of 6- to 30-day-old rats. The frequency of labelled neuronal nuclei was higher in the 12- to 30-day old rats than in the 6- to 10-day-old animals. The grain distribution pattern in autoradiographs was mostly nucleolar amounting to three to ten grains. Some other local labels were revealed, too. Only six Purkinje cells among 42,000 studied in 21 rats possessed heavy label (25 to 50 grains) distributed throughout the nucleus. Control estimations with deoxyribonuclease, hot perchloric acid and covering the autoradiographs again established that the Purkinje cells synthesize DNA perhaps for the purpose of DNA surplus accumulation and/or DNA repair in the neurons.