Suitability of the old fowl rectal caecum preparation for investigating the selectivity of beta-adrenergic drugs.
We tested alpha- and beta-adrenergic drugs on isolated strips of fowl rectal caecum from 14- to 16-week-old Warren hens. Basal tone and spontaneous motility were dose-dependently reduced by isoprenaline and all the selective beta-agonists tested (except xamoterol) with the following order of potency: isoprenaline=fenoterol=procaterol=clenbuterol>dobutamine> SR58611A. The results indicate that this tissue preparation consists almost entirely of beta2-adrenoceptors. This preparation may, therefore, be considered a suitable assay for discriminating beta1- from beta2-agonists according to their selectivity.
Carcano
R
R
Institute of Veterinary Pharmacology and Toxicology, Faculty of Veterinary Medicine, University of Milan, Italy.
Belloli
C
C
Arioli
F
F
Beretta
C
C
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000818:Animals; D002432:Cecum / Q000502:physiology*; D002645:Chickens; D002976:Clenbuterol / Q000494:pharmacology; D004280:Dobutamine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D005280:Fenoterol / Q000494:pharmacology; D005769:Gastrointestinal Motility / Q000187:drug effects*; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects*; D017265:Procaterol / Q000494:pharmacology; D013764:Tetrahydronaphthalenes / Q000494:pharmacology
D000316:Adrenergic alpha-Agonists; D000318:Adrenergic beta-Agonists; D013764:Tetrahydronaphthalenes; D005280:Fenoterol; D004280:Dobutamine; D007545:Isoproterenol; C076252:amibegron; D017265:Procaterol; D002976:Clenbuterol