[Role of cholinergic and adrenergic mechanisms in the action of ketamine and thiopental sodium on the structures of the hippocampal-reticular complex and the neocortex].

Under conditions of free behaviour of rabbits with electrodes implanted into the brain structures it was found that ketamine and sodium thiopental decrease the excitability in the dorsal hippocamp, reticular formation and periaqueductal gray matter of the midbrain. Excitability of the frontal neocortex increases during general anesthesia with ketamine and decreases during thiopental narcosis. Changes in excitability of the studied cerebral structures during general anesthesia can be determined by common N-cholinoblocking and alpha-adrenomimetic properties of ketamine and thiopental at the level of the dorsal hippocamp, cholinoblocking and adrenoblocking properties at the level of the reticular formation and central gray matter. In the frontal cortex ketamine presented properties of an M-cholinomimetic and adrenomimetic agent, sodium thiopental--those of a M-cholinoblocker and beta-adrenoblocker.