title: Stimulation of beta-adrenoceptors with isoprenaline inhibits small intestinal activity fronts and induces a postprandial-like motility pattern in humans.
abstract: OBJECTIVE
  To investigate the effects of beta-adrenoceptor stimulation, using the agonist isoprenaline and the antagonist propranolol, on migrating motor complexes in the upper intestine of 16 healthy human volunteers.
  
  
  METHODS
  Fasting motility was monitored using a tube with water perfused side holes connected to a pneumohydraulic system. Continuous eight hour recordings were obtained from each volunteer after a 12 hour fasting period. In all experiments, saline was given as control for the first four hour period and beta-adrenergic agents for the next four hours. In separate control studies, saline was given for the whole eight hour period.
  
  
  RESULTS
  Isoprenaline (2.5 micrograms/kg/min) reduced the number of activity fronts (phase III) of migrating motor complexes from 3 (2-4) in controls to 1 (0-2) during isoprenaline infusion (p < 0.01). Also, phase II-like activity replaced the regular motility pattern (p < 0.01). By contrast, propranolol (25 micrograms/kg/min) did not induce any significant changes in phase III compared with controls. Saline alone had no effect on motor activity.
  
  
  CONCLUSIONS
  Isoprenaline inhibited activity fronts in the human proximal small intestine and induced a postprandial-like motility pattern, whereas propranolol did not affect motor patterns. Stimulation of beta-adrenoceptors is of importance in the control of motor activity of the human small intestine, especially under stressful conditions with high adrenergic activity.
authors.affiliation: Department of Medicine, Karolinska Hospital, Stockholm, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Thollander
authors.forename: T H
authors.initials: TH
authors.lastname: Svensson
authors.forename: P M
authors.initials: PM
authors.lastname: Hellström
mesh_terms: D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000328:Adult; D001794:Blood Pressure / Q000187:drug effects; D005769:Gastrointestinal Motility / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007421:Intestine, Small / Q000187:drug effects*; D007545:Isoproterenol / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D016065:Myoelectric Complex, Migrating / Q000187:drug effects*; D011433:Propranolol / Q000494:pharmacology; D013268:Stimulation, Chemical
chemical_list: D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D011433:Propranolol; D007545:Isoproterenol