A comparison of the actions of acetylcholine and bradykinin on the guinea pig ileum.
Procaine (8.5 x 10(-5) M) inhibited the action of acetylcholine but not that of bradykinin on the guinea pig ileum. Attempts were made to identify the difference in stimulus-response coupling which would explain this difference in sensitivity. The responses to both agonists were dependent upon the presence of Ca2+ in the extracellular fluid, were inhibited to approximately the same extent by the addition of 0.25 mM Mn2+ to the bathing fluid and were equally sensitivity to reduction in Na+ concentration of the extracellular fluid. Neither acetylcholine nor bradykinin could provoke ileal contraction when Sr2+ was substituted for Ca2+. Thus there was no indication of the difference in the stimulus-response pathways for the two agonists which must exist to explain the differential sensitivity to procaine.
D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D001920:Bradykinin / Q000494:pharmacology*; D002118:Calcium / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D008345:Manganese / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D011343:Procaine / Q000494:pharmacology; D012964:Sodium / Q000494:pharmacology; D013324:Strontium / Q000494:pharmacology
D008345:Manganese; D011343:Procaine; D012964:Sodium; D000109:Acetylcholine; D001920:Bradykinin; D002118:Calcium; D013324:Strontium