Abstract
1. The pharmacological actions of DPN and ADS on the blood vessels of a surviving ear, on the cardiac systole of a living rabbit's heart's heart and of a surviving guinea pig's heart and on the rabbit's blood pressure were tested.
2. Both DPN and ADS had a contracting effect on the blood vessels of a rabbit's ear, an inhibitory effect on the cardiac systole of living rabbits and of a surviving guinea pig's heart, and the hypotensive effect on rabbits.
3. The inhibitory effect of both DPN and ADS on the cardiac systole of living rabbits and the hypotensive effect of DPN on rabbits were not influenced by atropine. No difference was seen in their effects with or without bilateral vagotomy at the neck.
4. DPN acted hypotensively even in the state of hypotension caused by a hypodermic injection of chloral hydrate.
