Glutamate and glutamine in the brain of the neonatal rat during hypercapnia

In order to study the influence of hypercapnia on the content of glutamate and glutamine in the developing brain, pregnant rats and their offspring were kept in CO2 rich (6-10%) atmosphere and the litters were killed at different ages between 4 and 28 days. In the hypercapnic rats the content of both amino acids in the brain increases with age with almost the same time course as in normocapnic rats. At any age the glutamate content is lower in the hypercapnic animals than in control rats, whereas the glutamine content, beyond the first 8 days of life is increased. Both effects are rapidly reversible on return to air breathing. Although the glutamate-glutamine system is in full development, the influence of hypercapnia can be compared to that observed in adult rats. Hypercapnia did not change the glutaminase and the glutamine synthetase activity of the brain.