title: A comparison of the effects of pirenzepine and atropine on gastric acid secretion, salivary secretion and pupil diameter in the rat.
abstract: The ability of pirenzepine and atropine, given i.v., to inhibit gastric acid and salivary secretion and increase pupil diameter has been assessed in the rat. Pirenzepine had a similar potency against acid secretion, ED 50 0.71 (0.41 to 1.1) mg.kg-1, and salivary secretion, ED 50 (0.43 to .59) mg.kg-1, whilst its potency was less in the eye, ED 50 1.8 (1.6 to 2.1) mg.kg-1. Atropine however, was more potent in reducing salivary secretion, ED 50 0.012 (0.010 to 0.016) mg.kg-1 and increasing pupil diameter, ED 50 0.028 (0.025 to 0.031) mg.kg-1 than in inhibiting gastric acid secretion, ED 50 0.056 (0.037 to 0.083) mg.kg-1. Therefore, that quantity of pirenzepine which inhibits gastric acid secretion by 50% will have only a slight effect on the eye and will inhibit salivary secretion by a similar magnitude. In contrast, the amount of atropine required to inhibit acid secretion by 50% will significantly increase pupil diameter and abolish salivary secretion.
mesh_terms: D000818:Animals; D001285:Atropine / Q000494:pharmacology*; D001570:Benzodiazepinones / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005744:Gastric Acid / Q000378:metabolism*; D008297:Male; D010890:Pirenzepine; D011680:Pupil / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains; D011976:Receptors, Muscarinic / Q000187:drug effects; D012463:Saliva / Q000378:metabolism*; D012469:Salivary Glands / Q000187:drug effects; D013270:Stomach / Q000187:drug effects
chemical_list: D001570:Benzodiazepinones; D011976:Receptors, Muscarinic; D010890:Pirenzepine; D001285:Atropine