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DNA synthetic ability in cerebella from temperature and handling stressed neonatal rats.

DNA synthetic ability of neonatal rat cerebellum was studied in two stressful conditions (cooling and excessive handling) which may be inadvertently imposed during the course of certain experiments. A rate study of the ability of animals handled excessively for 10 min to incorporate 14C-thymidine into the DNA tissue fraction (DNAF) from the acid soluble tissue fraction (ASF) of the cerebellum revealed a decreased DNA synthetic ability which lasted for 1 hr. Animals with very low core temperatures incorporated little 14C into the DNAF from the ASF 2 hr after an IP injection of 14C-thymidine. There was a proportional decrease in the ability to synthesize DNA as core temperature decreased.

Animal Husbandry↗

PubMedDate not supplied

Quantification of cell death in developing cerebellum by a 14C tracer method.

To study the question of whether or not cell death contributes significantly to normal or stressed postnatal brain development in a way which is biochemically quantifiable, we carried out an experiment to assess the amount of cell death in developing cerebellum. By measuring the loss of DNA content and the loss of 14C from labelled thymidine previously incorporated into the DNA fraction (DNAF) in X-irradiated neonatal animals, shown by histological methods to have cell death to the degree of degranulating the external granular layer (EGL), we showed that when cells die both label and DNA content are greatly decreased in the cerebellum. Experiments on both normal and malnourished animals showed that cell death does not contribute significantly to cerebellar development in either malnutrition-stressed or normal animals. Here, we present a biochemical tool for assessing cell death and evidence that cell death does not contribute significantly to cerebellar development.

Animals↗