Regulation of regional lung perfusion by nitric oxide.
Improved oxygenation has previously been shown in patients with acute lung injury when ventilated in prone position. We hypothesized that this was due to higher regional production of nitric oxide in dorsocaudal lung regions. We measured nitric oxide synthase mRNA expression and nitric oxide production by citrulline assay in ventral and dorsal lung tissue from patients. In volunteers, regional lung perfusion in prone and supine postures was assessed by single photon emission computed tomography using (99m)Tc macroaggregated albumin before and after inhibition of nitric oxide synthase by N(G)-monomethyl-L-arginine infusion. Nitric oxide synthase mRNA expression and nitric oxide production were significantly higher in dorsal compared with ventral lung regions. In supine posture, lung perfusion was shifted to ventral parts during nitric oxide synthase inhibition, whereas in the prone posture lung perfusion remained unchanged. Our results suggest a role for endogenous nitric oxide in regulation of regional pulmonary perfusion.
Rimeika
Danguole
D
Department of Anaesthesiology, Karolinska Hospital, S-171 76 Stockholm, Sweden. sten.lindahl@ks.se
Nyrén
Sven
S
Wiklund
N Peter
NP
Koskela
Lotta Renström
LR
Tørring
Anders
A
Gustafsson
Lars E
LE
Larsson
Stig A
SA
Jacobsson
Hans
H
Lindahl
Sten G E
SG
Wiklund
Claes U
CU
D000136:Acid-Base Equilibrium / Q000187:drug effects / Q000502:physiology; D000368:Aged; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000473:pathology; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011187:Posture / Q000502:physiology; D011652:Pulmonary Circulation / Q000187:drug effects / Q000502:physiology*; D011877:Radionuclide Imaging; D014018:Tissue Distribution; D019323:omega-N-Methylarginine / Q000494:pharmacology
D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase