AJP - Gastrointestinal and Liver Physiology, Vol 271, Issue 6 1039-G1042, Copyright © 1996 by American Physiological Society
Continuous measurement of gastric nitric oxide production
A. Aneman, J. Snygg, L. Fandriks and A. Pettersson
Department of Anesthesiology, Sahlgrens' University Hospital, Gothenborg, Sweden.
With the use of a double-lumen catheter, nitric oxide (NO) was dialyzed
across a Gore-Tex membrane into a gas phase and subsequently analyzed
on-line by chemiluminescence. This new technique for the continuous
measurement of NO was evaluated bench-side and applied in the human stomach
in vivo to measure the nonenzymatic formation of NO generated from nitrite
in an acidic milieu. A linear relation (r2 = 0.991, P < 0.0001) between
concentrations of NO in aqueous solutions (2.5-52.5 mM) and NO in the
corresponding gas phases obtained by the dialysis technique (50-1,000 parts
per billion) validated the present method for quantitative analyses of NO.
Interassay and intra-assay coefficients of variation at all concentrations
of NO for six experiments were < 5%. High intragastric concentrations of
NO (in the micromolar range) were found during basal conditions. The
requirement of both nitrite from the saliva and an acidic environment for
NO formation is indicated, since depletion of saliva as well as acid
neutralization greatly reduced gastric NO concentrations. Furthermore,
large amounts of gastric NO were formed after intake of sodium nitrate.
With the use of this technique, NO can be continuously measured with
accuracy experimentally and clinically in any organ accessible to
intubation.
