Acute effects of Helicobacter pylori extracts on gastric mucosal blood flow in the mouse.
OBJECTIVE
To investigate the mechanisms underlying the reduction in gastric blood flow induced by a luminal water extract of Helicobacter pylori (HPE).


METHODS
The stomachs of isoflurane-anesthetized mice were exteriorized, and the mucosal surface exposed. Blood flow was measured with the laser-Doppler technique, and systemic arterial blood pressure monitored. C57BL/6 mice were exposed to water extract produced from H pylori strain 88-23. To investigate the role of a nerve- or iNOS-mediated pathway, we used intraluminal lidocaine and iNOS-/- mice. Blood flow response to the endogenous nitric oxide synthase inhibitor asymmetric dimethyl arginine (ADMA) was also assessed.


RESULTS
In wild-type mice, HPE decreased mucosal blood flow by approximately 30%. This reduction was abolished in iNOS-deficient mice, and by pre-treatment with lidocaine. Luminally applied ADMA resulted in reduction in blood flow similar to that observed in wild-type mice exposed to HPE.


CONCLUSIONS
A H pylori water extract reduces gastric mucosal blood flow acutely through iNOS- and nerve-mediated pathways.
Henriksnäs
Johanna
J
Department of Medical Cell Biology, Uppsala University, PO Box 571, SE-751 23 Uppsala, Sweden. johanna.henriksnas@mcb.uu.se
Atuma
Christer
C
Phillipson
Mia
M
Sandler
Stellan
S
Engstrand
Lars
L
Holm
Lena
L
D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D001783:Blood Flow Velocity / Q000187:drug effects; D005753:Gastric Mucosa / Q000098:blood supply* / Q000187:drug effects / Q000294:innervation / Q000382:microbiology*; D016480:Helicobacter pylori / Q000737:chemistry / Q000472:pathogenicity*; D008012:Lidocaine / Q000494:pharmacology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D052247:Nitric Oxide Synthase Type II / Q000172:deficiency / Q000235:genetics / Q000502:physiology; D015398:Signal Transduction / Q000187:drug effects; D014867:Water
D014867:Water; C018524:N,N-dimethylarginine; D001120:Arginine; D008012:Lidocaine; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse