title: Anticholinergic agents prevent guinea-pig airway constriction induced by histamine, bradykinin and leukotriene C4: Relationship to circulating TXA2.
abstract: Various doses of histamine, bradykinin and leukotriene C4 caused bronchoconstriction in anaesthetized guinea-pigs which were breathing spontaneously or artificially ventilated; there was a simultaneous, dose-related increase in circulating TXA2. The animals were prepared for continuous recording of extracorporeal circulation in order to detect the appearance in the blood of bioassayable levels of TXA2 -like substance. Furthermore, a TXA2 derivative, the mono-O-Me-TXB2, was radioimmunoassayed. Atropine, oxytropium bromide and ipratropium bromide given in mumol doses prevented both the increased airway resistance and the release of TXA2-like substance in the blood Pirenzepine dihydrochloride was the least active of the drugs tested. The protecting activity of anticholinergics and the relationship with their ability to affect TXA2-like substance generation suggest a new site of action for these drugs besides the blockade of muscarinic receptors.
mesh_terms: D000403:Airway Resistance / Q000187:drug effects*; D000818:Animals; D001920:Bradykinin / Q000037:antagonists & inhibitors; D005260:Female; D006168:Guinea Pigs; D006633:Histamine Antagonists; D008297:Male; D010276:Parasympatholytics / Q000494:pharmacology*; D013189:SRS-A / Q000037:antagonists & inhibitors; D013928:Thromboxane A2 / Q000097:blood*; D013931:Thromboxanes / Q000097:blood*
chemical_list: D006633:Histamine Antagonists; D010276:Parasympatholytics; D013189:SRS-A; D013931:Thromboxanes; D013928:Thromboxane A2; D001920:Bradykinin