THE EFFECT OF PHYSOSTIGMINE AND NEOSTIGMINE ON THE CONCENTRATION OF GLYCOGEN IN VARIOUS BRAIN STRUCTURES OF THE RAT

Abstract—

• 1 Hypothalamus, mesencephalon, cerebral cortex, cerebellar cortex and medulla oblongata of the rat brain contain varying amounts of glycogen. The highest concentration was found in the medulla, and the lowest in the hypothalamus.
• 2 Low doses of physostigmine produced a significant decrease in the concentration of glycogen in mesencephalon, cerebral cortex, cerebellar cortex and medulla. Higher doses of physostigmine were necessary to produce glycogenolysis in the hypothalamus. In the first four structures glycogen stores were almost equally sensitive to the action of physostigmine. Neostigmine did not affect brain glycogen. The glycogenolytic effect of physostigmine was dose-dependent.
• 3 Both atropine and propranolol were found to block the glycogenolytic effect of physostigmine in brain.
• 4 It is concluded that probably both cholinergic and adrenergic processes participate in the glycogenolytic effect of physostigmine. It is suggested that physostigmine initiates the cholinergic processes which then trigger adrenergic processes.