title: Identification of beta-adrenergic receptor subtypes mediating relaxation in isolated equine ileum.
abstract: OBJECTIVE
  To identify beta-adrenergic receptor subtypes in ileum smooth muscle of the horse.
  
  
  METHODS
  Isolated strips of equine longitudinal ileum smooth muscle and membrane preparations from smooth muscle of the intestinal wall.
  
  
  METHODS
  Functional assays and radioligand binding assays.
  
  
  RESULTS
  Relaxation of ileum longitudinal smooth muscle proved to be mainly caused by stimulation of beta-atypical and beta 2-adrenergic receptors. Binding studies on cell membranes indicated that the total beta-adrenergic receptors population consists of 54% beta-atypical, 34% beta 2- and 12% beta 1-subtypes.
  
  
  CONCLUSIONS
  The data suggest that sympathetic relaxation of equine ileum smooth muscle depends mainly on beta-atypical receptor subtypes activation, with a minor contribution by beta 2-subtypes.
  
  
  CONCLUSIONS
  The important role of beta-atypical adrenergic receptor subtypes in the relaxation of equine ileum suggests possible clinical use of selective beta-atypical receptor agonists to control intestinal disturbances.
authors.affiliation: Department of Animal Pathology, University of Turin, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Re
authors.forename: C
authors.initials: C
authors.lastname: Belloli
authors.forename: P
authors.initials: P
authors.lastname: Badino
authors.forename: F
authors.initials: F
authors.lastname: Arioli
authors.forename: A
authors.initials: A
authors.lastname: Novelli
authors.forename: C
authors.initials: C
authors.lastname: Girardi
authors.forename: C
authors.initials: C
authors.lastname: Beretta
mesh_terms: D000318:Adrenergic beta-Agonists / Q000378:metabolism / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D001667:Binding, Competitive; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure; D005260:Female; D006736:Horses / Q000502:physiology*; D007082:Ileum / Q000737:chemistry / Q000166:cytology / Q000502:physiology*; D008297:Male; D009126:Muscle Relaxation / Q000502:physiology*; D009130:Muscle, Smooth / Q000737:chemistry / Q000502:physiology* / Q000648:ultrastructure; D011412:Propanolamines / Q000378:metabolism / Q000494:pharmacology; D011485:Protein Binding; D011869:Radioligand Assay / Q000379:methods / Q000662:veterinary; D011943:Receptors, Adrenergic, beta / Q000032:analysis / Q000378:metabolism / Q000502:physiology*; D018342:Receptors, Adrenergic, beta-1 / Q000032:analysis / Q000378:metabolism / Q000502:physiology; D018343:Receptors, Adrenergic, beta-2 / Q000032:analysis / Q000378:metabolism / Q000502:physiology; D014316:Tritium
chemical_list: D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D011412:Propanolamines; D011943:Receptors, Adrenergic, beta; D018342:Receptors, Adrenergic, beta-1; D018343:Receptors, Adrenergic, beta-2; D014316:Tritium; C033394:CGP 12177