The action of angiotensin on the human colon in vitro

Abstract

. The action of angiotensin on the circular and longitudinal muscle of the human colon has been studied in vitro. The ED50 value (g/ml) of circular muscle was 8.7 × 10−8 and of longitudinal muscle 3.1 × 10−8, while the corresponding figures for acetylcholine were 1.6 × 10−6 and 1.1 × 10−6, respectively. Angiotensin caused a sustained contraction associated with prolonged tachyphylaxis. . As the action of angiotensin was not antagonized by atropine, hexamethonium or procaine, angiotensin appeared to act directly on the smooth muscle of the human colon. . Lidoflazine is not a specific antagonist of angiotensin. 1970 British Pharmacological Society