Caffeine does not modulate nutritive blood flow to rat gastric submucosa--a microdialysis study.
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.
Cibicek
Norbert
N
Institute of Clinical Biochemistry and Diagnostics, Charles University, Prague, Czech Republic. cibicek@seznam.cz
Zivna
Helena
H
Cibicek
Jaroslav
J
Cermakova
Eva
E
Vorisek
Viktor
V
Malakova
Jana
J
Micuda
Stanislav
S
Palicka
Vladimir
V
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
D009569:Nitric Oxide; D002110:Caffeine; D008315:Malondialdehyde