title: Motility changes induced by intraluminal FeSO4 in guinea pig jejunum.
abstract: BACKGROUND
  Dietary iron supplementation is associated with gastrointestinal (GI) side effects including vomiting, nausea, and diarrhea. Although inorganic iron in high concentrations may be damaging to the intestinal mucosa, we hypothesize that there are physiological effects on the GI tract that occur at concentrations achieved by supplementation. Thus, our aim was to investigate the effect of intraluminal ferrous sulfate (FeSO4 ) on jejunal motility.
  
  
  METHODS
  Segments of guinea pig jejunum were cannulated and the intraluminal pressure recorded with a transducer, while movements were recorded with a video camera. Peristaltic threshold was the oral pressure that evoked four consecutive propulsive contractions. The nutrients decanoic acid (1 mM), l-phenylalanine (50 mM), or the micronutrient FeSO4 (1 mM) were infused intraluminally. We also tested the effect of FeSO4 on electrochemically detected serotonin (5-HT, 5-hydroxytryptamine) released from in vitro tissues, both at rest and following mechanical stimulation.
  
  
  RESULTS
  The jejuna peristaltic threshold was significantly decreased by all three nutrients: FeSO4 : 31 ± 2-23 ± 3 mmH2 O; decanoic acid: 27 ± 2-14 ± 2 mmH2 O; and l-phenylalanine: 30 ± 3-14 ± 3mmH2 O. Of the three, only decanoic acid induced segmentation, while FeSO4 inhibited decanoic acid-induced segmentation. Resting 5-HT release was increased by FeSO4 (128% of control), but mechanically evoked 5-HT release was reduced (70% of control).
  
  
  CONCLUSIONS
  These data suggest that some luminal effects of inorganic iron on jejunal motility could be mediated through a pathway involving altered release of 5-HT. A better understanding of the interaction between luminal iron and 5-HT containing enterochromaffin cells could improve iron supplementation strategies, thus reducing side effects.
authors: Department of Physiology, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia.
authors: K
authors: K
authors: Wang
authors: R L
authors: RL
authors: Bertrand
authors: S
authors: S
authors: Senadheera
authors: K E
authors: KE
authors: Polglaze
authors: T V
authors: TV
authors: Murphy
authors: S L
authors: SL
authors: Sandow
authors: L
authors: L
authors: Liu
authors: J C
authors: JC
authors: Bornstein
authors: P P
authors: PP
authors: Bertrand
mesh_terms: D000818:Animals; D003652:Decanoic Acids / Q000633:toxicity; D019587:Dietary Supplements / Q000633:toxicity; D005260:Female; D005296:Ferrous Compounds / Q000633:toxicity*; D005769:Gastrointestinal Motility / Q000187:drug effects*; D006168:Guinea Pigs; D007583:Jejunum / Q000187:drug effects* / Q000503:physiopathology; D008297:Male; D010649:Phenylalanine / Q000633:toxicity; D012701:Serotonin / Q000032:analysis
chemical_list: D003652:Decanoic Acids; D005296:Ferrous Compounds; D012701:Serotonin; C020748:ferrous sulfate; D010649:Phenylalanine; C031071:decanoic acid
keywords: intestinal reflexes; iron supplementation; serotonin