title: POTENTIATION OF THE ACTION OF BRADYKININ ON SMOOTH MUSCLE BY CHYMOTRYPSIN,  CHYMOTRYPSINOGEN AND TRYPSIN.
abstract: Chymotrypsin, chymotrypsinogen and trypsin sensitized the guinea-pig isolated ileum and rat isolated uterus preparations to the action of bradykinin, whilst the responses to histamine, acetylcholine and 5-hydroxytryptamine were unaffected. Chymotrypsin caused a quick contraction of the guinea-pig ileum which was abolished by mepyramine and therefore probably mediated by histamine. Trypsin contracted the rat uterus as well as the guinea-pig ileum; the latter contraction was slow, resistant to mepyramine and gave rise to tachyphylaxis. It is suggested that isolated smooth muscle preparations should be treated with chymotrypsin for use in the estimation of minute amounts of bradykinin.
mesh_terms: D000109:Acetylcholine; D000818:Animals; D018926:Anti-Allergic Agents; D001920:Bradykinin; D002918:Chymotrypsin; D002919:Chymotrypsinogen; D004792:Enzyme Precursors; D005260:Female; D006168:Guinea Pigs; D006632:Histamine; D006634:Histamine H1 Antagonists; D006801:Humans; D007082:Ileum; D009119:Muscle Contraction; D009130:Muscle, Smooth; D010600:Pharmacology; D051381:Rats; D012106:Research; D012701:Serotonin; D013618:Tachyphylaxis; D014357:Trypsin; D014599:Uterus
chemical_list: D018926:Anti-Allergic Agents; D004792:Enzyme Precursors; D006634:Histamine H1 Antagonists; D012701:Serotonin; D006632:Histamine; D002919:Chymotrypsinogen; D002918:Chymotrypsin; D014357:Trypsin; D000109:Acetylcholine; D001920:Bradykinin
keywords: ACETYLCHOLINE; ANTIHISTAMINICS; BRADYKININ; CHYMOTRYPSIN; ENZYME PRECURSORS; EXPERIMENTAL LAB STUDY; GUINEA PIGS; HISTAMINE; ILEUM; MUSCLE CONTRACTION; MUSCLE, SMOOTH; PHARMACOLOGY; RATS; SEROTONIN; TACHYPHYLAXIS; TRYPSIN; UTERUS