title: Caffeine does not modulate nutritive blood flow to rat gastric submucosa--a microdialysis study.
abstract: OBJECTIVE
  Coffee irritates the gastric mucosa disrupting its barrier and increasing the risk of peptic ulcers. However, caffeine's contribution to these effects has not yet been elucidated. In this study we looked at the local effect of caffeine on the microcirculation and nitric oxide production in rats together with systemic marker of oxidative stress malondialdehyde as possible mechanisms whereby caffeine might participate in mucosal barrier impairment.
  
  
  METHODS
  Four groups of rats were anesthetized and administered as a bolus four different intraperitoneal doses of caffeine (0, 1, 10 and 50 mg kg(-1) b.wt.). The gastric submucosal microcirculation and nitric oxide production were then recorded for 2.5 hours by in situ microdialysis using the flow marker ethanol. At the completion of the experiments, plasma caffeine and malondialdehyde levels as well as morphological mucosal injury were determined.
  
  
  RESULTS
  There were no major differences in the macro- or microscopic pictures of the mucosa among the groups. Local microcirculatory (ethanol out/in ratio) and nitric oxide monitoring failed to demonstrate statistically significant changes as did measurement of plasma malondialdehyde in response to caffeine injections.
  
  
  CONCLUSIONS
  Caffeine per se seems unlikely to contribute to the gastric mucosal barrier injury associated with coffee consumption by alterations in nutritive blood flow, nitric oxide production or aggravation of systemic oxidative stress. This information is relevant for better understanding of the mechanisms involved in caffeine-mediated influences on gastric physiology in relation to the irritant effects of coffee.
authors.affiliation: Institute of Clinical Biochemistry and Diagnostics, Charles University, Prague, Czech Republic. cibicek@seznam.cz
authors.forename: Norbert
authors.initials: N
authors.lastname: Cibicek
authors.forename: Helena
authors.initials: H
authors.lastname: Zivna
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Cibicek
authors.forename: Eva
authors.initials: E
authors.lastname: Cermakova
authors.forename: Viktor
authors.initials: V
authors.lastname: Vorisek
authors.forename: Jana
authors.initials: J
authors.lastname: Malakova
authors.forename: Stanislav
authors.initials: S
authors.lastname: Micuda
authors.forename: Vladimir
authors.initials: V
authors.lastname: Palicka
mesh_terms: D000818:Animals; D002110:Caffeine / Q000494:pharmacology*; D005753:Gastric Mucosa / Q000098:blood supply* / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D017551:Microdialysis; D009569:Nitric Oxide / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
chemical_list: D009569:Nitric Oxide; D002110:Caffeine; D008315:Malondialdehyde