Does atropine block antigen-induced contraction in canine bronchial rings? A preliminary report.
Isometric contractions recorded with a strain gauge, were elicited with cumulative doses of ascaris suum antigen on fresh canine bronchial rings from 8 dogs. Fifteen rings from 2 spontaneously sensitized dogs reacted with contractions to the antigen, while 11 rings from other dogs did not react. Seven sensitized rings were re-challenged after atropine, which significantly prevented the antigen from contracting these rings at a time when antigen contracted 3 non-atropinized, simultaneously tested rings from the same bronchi. Acetylcholine may play a part in the smooth-muscle contraction induced by antigen, or atropine may inhibit early activation of the "arachidonic acid cascade". The findings may be of interest in the interpretation of anti-muscarinic drugs as inhibitors of reflex cholinergic activity versus local anti-allergic effect.
D000818:Animals; D000941:Antigens / Q000008:administration & dosage; D001285:Atropine / Q000494:pharmacology*; D001980:Bronchi / Q000187:drug effects*; D001985:Bronchial Provocation Tests; D004285:Dogs; D007537:Isometric Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*
D000941:Antigens; D001285:Atropine