Influence of a perinatal hypoxia on the carbonic anhydrase activity in different brain regions of the rat.

Homogenates of striatum, hippocampus and cerebral cortex of the rat brain were investigated for carbonic anhydrase activities. During ontogeny the enzyme activities increase with proceeding gliogenesis. At the 5th postnatal day (PD) prenatal hypoxia (17th day of gestation (GD)--birth) is followed by a 4-fold increase of carbonic anhydrase (CA) activity in the hippocampus. After postnatal hypoxia (2nd-10th day of life) CA activity in all investigated brain regions rise. At the 11th PD the values were 190 (cerebral cortex), 242 (striatum) and 176 (hippocampus) per cent of control. Noradrenaline (10(-6)M) enhanced CA activity in cerebral cortex and hippocampus about 2-fold. Dopamine (10(-6)M) caused an increase in the striatum up to 210% of control. The increased CA activity after hypoxia is assumed to be a functional response to activation of the glia by catecholamines.