Action of drugs on the central nervous system with special reference to acetyl choline

Abstract

1. Stimulation of the central end of the vagus and injection of acetyl choline in the ventricles of the brain have a similar effect on respiration, namely a marked depression of respiratory movements.2. Atropine and physostigmine do not modify the effect of central vagal stimulation or intraventricular acetyl choline injection.3. In a small proportion of cases an acetyl-cholinelike substance appears in the cerebro- spinal fluid after stimulation of the central end of the vagus when no such substance is present in the normal cerebro-spinal fluid.4. The physiological and physico -chemical properties of the brain extracts of cats and rabbits show a close resemblance to the properties of acetyl choline.5. Various biological tests applied to the brain extracts show that acetyl choline is normally presents in the brain.6. The concentration of acetyl choline is highest i the basal ganglia, and lowest in the cerebellum; !the concentration in the cortex is slightly lower than that in the basal ganglia.7.. The acetyl choline equivalent in the basal ganglia, is about 0.44 y in cats and about 0.14γ in rabbit's.8. It is suggested that the effects of stimulation of the central end of the vagus are due to liberation' of acetyl choline in the central nervous system.