[Aldehyde dehydrogenase activity in the rat brain during ontogenesis].

By means of the quantitative histochemical method aldehyde dehydrogenase (1.2.1.3; AlDH) activity has been studied in the rat brain and spinal cord structures. AlDH activity (acetaldehyde is used as a substrate) in the barrier structures of the brain (vascular and villous ependymocytes of the cerebral ventricles, endothelium of blood capillaries) makes only 10-30% during the antenatal period and then increases gradually, reaching the activity specific for mature animals by the 20th-40th day after birth. Up to the 10th day of the postnatal development AlDH activity of neurocytes of various types makes 45-70%, and then increases sharply, and by the 20th day is approaches the definitive one. AlDH activity of the spinal cord motoneurons in old rats (2-year-old) essentially surpasses the control. In the white cerebral substance and its gliocytes from the 10th up to the 40th day after birth AlDH activity sharply increases; this coincides with myelinization of the CNS. Dynamics of aldehyde-oxidating ability is probably connected with natural changes in the CNS metabolism during ontogenesis. At the same time, it reflects a low level in stability of the developing brain to the damaging effect of exogenic ethanol and especially to its toxic metabolite--acetaldehyde.