[Relation of binding by metabolism of gamma-aminobutyric acid and various reactions of the Krebs cycle in the rat brain].

The comparison has been made for the following items: intensity of pyruvate alpha-ketoglutarate, succinate oxidation, the gamma-aminobutyric acid (GABA) formation rate, utilization, total content of GABA, glutamate and alanine, the bound/free form ratio of GABA and glutamate, intensity of binding and desorption of exogenic [I-14C]GABA in homogenates of the cortex, cerebellum and brainstem of the Wistar rats. It is revealed that the intensity of ketoacids oxidation is significantly lower in the cerebellum than in the cortex, but the maximal activity of the enzymes of GABA formation and utilization is higher, due to which considerable oxidation of alpha-ketoglutarate transforming into succinate is possible proceeding the GABA shunt pathway. The cortex homogenates contrary to the cerebellum ones are characterized by the reliably higher intensity of ketoacid oxidation and by insignificant contribution of the GABA-shunt to the succinate production. These differences are in line with the reliably higher content of endogenic bound GABA in the cortex as compared to the cerebellum, with a higher level of binding of exogenic labelled GABA and with less pronounced desorption of the label from neurostructures. An assumption is advanced that the observed differences are related to the known high sensitivity of the cortex and to relative resistance of cerebellum to hypoxia and hypoglycemia.