An Unidentified Pharmacologically Active Substance extracted from Cerebral Hemispheres

WHILE estimating the 5-hydroxytryptamine content of rat brain, it was observed that the acetone extract stimulated the isolated rat uterus even in the presence of atropine and 2-bromo-lysergic acid diethylamide (BOL-148, 10^-7 gm./ml.). Different parts of the rat brain were then separately extracted and examined, and by far the largest proportion of the active material was found in the cerebral hemispheres. Similar results were obtained when extracts of different areas of other mammalian brains were tested. A study was therefore made of the properties of this smooth-muscle-stimulating substance present in extracts of cerebral hemispheres of mammals.