[Role of GABA and its derivatives in regulating cerebral circulation].

GABA, its derivative -- gamma-hydroxybuturic acid and metabolite --succinic acid have a pronounced dilatatory activity on cerebral circulation in various brain parts. GABA increases cerebral circulation by 25.3%, gamma-hydroxybutyric acid by 35.9% and sucinic acid by 20.4%. In ischaemia of the brain a relationship has been established between cerebral circulation, changes in the GABA system in brain and in the walls of cerebral arteries. The content of GABA increases following enhancement of GAD activity and inhibition of GABA-T. The increase of endogenous GABA level in brain during hypoxia of the brain brings to an improvement of blood circulation through increasing collateral vessels. Experiments with GABA-T inhibition by aminooxyacetic acid give direct evidence about the role of the GABA system in cerebral blood circulation. This mechanism is evaluated by us as an example of an autoregulatory system that is realized by a feed-back mechanism providing the adaptability and compensatory function of cerebral haemodynamics to changing conditions.