Choline and its homolog, acetylcholine, found in tissue extracts,1 are believed to stimulate primitive receptors or end-organs2 which are often, but not necessarily, related to the vagus or parasympathetic nerves. The action of choline on the heart, iris and gastro-intestinal system closely resembles that which follows stimulation of the parasympathetic nerves. Whereas its action on blood vessels, vasodilatation,3 although it follows vagus or depressor nerve stimulation, cannot be said to result directly from the action of parasympathetic impulses on the blood vessel and organs.
The parallelism4 between the action of acetylcholine and vagus stimulation makes it of interest to determine whether the vessels of the brain, which also dilate on vagus stimulation, act similarly after injections of acetylcholine.
F. Muller.5 using the Gottlieb modification of the Roy and Sherrington brain oncometer, studied the changes in brain volume and in blood pressure when choline was injected
WOLFF HG. THE CEREBRAL CIRCULATIONXI a. THE ACTION OF ACETYLCHOLINE. Arch NeurPsych. 1929;22(4):686-690. doi:10.1001/archneurpsyc.1929.02220040041003