title: Regulation of regional lung perfusion by nitric oxide.
abstract: 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.
authors.affiliation: Department of Anaesthesiology, Karolinska Hospital, S-171 76 Stockholm, Sweden. sten.lindahl@ks.se
authors.forename: Danguole
authors.initials: D
authors.lastname: Rimeika
authors.forename: Sven
authors.initials: S
authors.lastname: Nyrén
authors.forename: N Peter
authors.initials: NP
authors.lastname: Wiklund
authors.forename: Lotta Renström
authors.initials: LR
authors.lastname: Koskela
authors.forename: Anders
authors.initials: A
authors.lastname: Tørring
authors.forename: Lars E
authors.initials: LE
authors.lastname: Gustafsson
authors.forename: Stig A
authors.initials: SA
authors.lastname: Larsson
authors.forename: Hans
authors.initials: H
authors.lastname: Jacobsson
authors.forename: Sten G E
authors.initials: SG
authors.lastname: Lindahl
authors.forename: Claes U
authors.initials: CU
authors.lastname: Wiklund
mesh_terms: 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
chemical_list: D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase