A ganglion-stimulating principle present in peptone.

One of us (W. T. B.) has previously described a pressor effect of peptone in the rat. This effect was considered secondary to a release of sympathin by the stimulation of sympathetic ganglia. The present experiments show that peptone causes contraction of guinea-pig ileum and inferior eyelid of the rat which is antagonized by hexamethonium. Atropine inhibits equiactive doses of peptone and acetylcholine on the guinea-pig ileum and eserine potentiates them. Boiling peptone in concentrated hydrochloric acid or N sodium hydroxide destroys its activity; incubation with proteolytic enzymes (trypsin, pepsin, and chymotrypsin) has no effect on its activity. It is concluded that peptone acts upon the intramural ganglia of the guinea-pig ileum and on sympathetic ganglia which supply the inferior eyelid of the rat.