title: In vitro spontaneous contractile activity of colonic smooth muscle in naive Lewis rats: Acute effect of gonadal hormones.
abstract: OBJECTIVE
  Functional gastrointestinal disorders affect females more often. Changes in colonic motility may be etiological co-factors for the clinical symptoms. The aim of the present study was to analyze the influence of gonadal hormones on colonic contractile activity.
  
  
  METHODS
  In vitro measurements of colonic contractile activity in longitudinal smooth muscle strips of female and male Lewis rats were performed in an organ chamber experiment. After the administration of a gonadal hormone estradiol [EST], progesterone [PROG] and testosterone [TEST]) or ethanol solution as control, stimulation with acetylcholine (ACh) or inhibition with norepinephrine (NE) was performed.
  
  
  RESULTS
  Compared to the smooth muscle strips of male rats, significantly higher spontaneous colonic contractile activity (SCCA) was observed in female animals. Increasing doses of ACh showed the progressive stimulation of SCCA whereas rising doses of NE resulted in a stepwise inhibition of SCCA, respectively. EST superfusion displayed an inhibitory effect on SCCA in both sexes and inhibited the ACh effect in female rats. Similarly, acute superfusion with high-dose PROG inhibited SCCA in females. Acute TEST superfusion inhibited SCCA in males and led to significant higher colonic contractile activity in males following subsequent stimulation with ACh. In female rats, the inhibitory effect of NE was reduced by prior exposure to TEST.
  
  
  CONCLUSIONS
  In our in vitro study the acute exposure of colonic smooth muscle tissue to gonadal hormones led to sex-dependent changes in SCCA and translated in a modified response of smooth muscle strips to both pro-contractile and anti-contractile neurotransmitters.
authors.affiliation: Department of Visceral Surgery and Medicine, University Hospital of Berne, Bern, Switzerland.|Department of Clinical Research, University Hospital of Berne, Bern, Switzerland.
authors.forename: Christine
authors.initials: C
authors.lastname: Baumgartner
authors.affiliation: Department of Visceral Surgery and Medicine, University Hospital of Berne, Bern, Switzerland.|Department of Clinical Research, University Hospital of Berne, Bern, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Hubacher
authors.affiliation: Department of Visceral Surgery and Medicine, University Hospital of Berne, Bern, Switzerland.|Department of Clinical Research, University Hospital of Berne, Bern, Switzerland.
authors.forename: Magali
authors.initials: M
authors.lastname: Krayer
authors.affiliation: Department of Visceral Surgery and Medicine, University Hospital of Berne, Bern, Switzerland.|Department of Clinical Research, University Hospital of Berne, Bern, Switzerland.|Department of Internal Medicine, Forchheim Clinic, Forchheim, Germany.
authors.forename: Juergen
authors.initials: J
authors.lastname: Gschossmann
mesh_terms: D000109:Acetylcholine / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D003106:Colon / Q000187:drug effects* / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D005769:Gastrointestinal Motility / Q000187:drug effects* / Q000502:physiology; D042341:Gonadal Hormones / Q000494:pharmacology*; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects* / Q000502:physiology; D009130:Muscle, Smooth / Q000187:drug effects* / Q000502:physiology; D018377:Neurotransmitter Agents / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D011374:Progesterone / Q000494:pharmacology; D011917:Rats, Inbred Lew; D012727:Sex Characteristics; D013739:Testosterone / Q000494:pharmacology; D046509:Tissue Culture Techniques
chemical_list: D042341:Gonadal Hormones; D018377:Neurotransmitter Agents; D013739:Testosterone; D011374:Progesterone; D004958:Estradiol; D000109:Acetylcholine; D009638:Norepinephrine
keywords: colonic smooth muscle; functional bowel disorder; gonadal hormone; irritable bowel syndrome; motility; organ chamber