Biomaterial Database

Nitric oxide modulation of pulmonary blood flow distribution in lobar hypoxia. 1995

F Fredén, and S Z Wei, and J E Berglund, and C Frostell, and G Hedenstierna

Department of Clinical Physiology, Uppsala University Hospital, Sweden.

BACKGROUND Nitric oxide, endogenously produced or inhaled, has been shown to play an important role in the regulation of pulmonary blood flow. The inhalation of nitric oxide reduces pulmonary arterial pressure in humans, and the blockade of endogenous nitric oxide production increases the pulmonary vascular response to hypoxia. This study was performed to investigate the hypothesis that intravenous administration of an nitric oxide synthase inhibitor and regional inhalation of nitric oxide can markedly alter the distribution of pulmonary blood flow during regional hypoxia. METHODS Hypoxia (5% O2) was induced in the left lower lobe of the pig, and the blood flow to this lobe was measured with transit-time ultrasound. Nitric oxide was administered in the gas ventilating the hypoxic lobe and the hyperoxic lung regions with and without blockade of endogenous nitric oxide production by means of N omega-nitro-L-arginine methyl ester (L-NAME). RESULTS Hypoxia in the left lower lobe reduced blood flow to that lobe to 27 +/- 3.9% (mean +/- SEM) of baseline values (P < 0.01). L-NAME caused a further reduction in lobar blood flow in all six animals to 12 +/- 3.5% and increased arterial oxygen tension (PaO2) (P < 0.01). Without L-NAME, the inhalation of nitric oxide (40 ppm) to the hypoxic lobe increased lobar blood flow to 66 +/- 5.6% of baseline (P < 0.01) and, with L-NAME, nitric oxide delivered to the hypoxic lobe resulted in a lobar blood flow that was 88 +/- 9.3% of baseline (difference not significant). When nitric oxide was administered to the hyperoxic lung regions, after L-NAME infusion, the blood flow to the hypoxic lobe decreased to 2.5 +/- 1.6% of baseline and PaO2 was further increased (P < 0.01). CONCLUSIONS By various combinations of nitric oxide inhalation and intravenous administration of an nitric oxide synthase inhibitor, lobar blood flow and arterial oxygenation could be markedly altered during lobar hypoxia. In particular, the combination of intravenous L-NAME and nitric oxide inhalation to the hyperoxic regions almost abolished perfusion of the hypoxic lobe and resulted in a PaO2 that equalled the prehypoxic values. This possibility of adjusting regional blood flow and thereby of improving PaO2 may be of value in the treatment of patients undergoing one-lung ventilation and of patients with acute respiratory failure.

UI	MeSH Term	Description	Entries
D009569	Nitric Oxide	A free radical gas produced endogenously by a variety of mammalian cells, synthesized from ARGININE by NITRIC OXIDE SYNTHASE. Nitric oxide is one of the ENDOTHELIUM-DEPENDENT RELAXING FACTORS released by the vascular endothelium and mediates VASODILATION. It also inhibits platelet aggregation, induces disaggregation of aggregated platelets, and inhibits platelet adhesion to the vascular endothelium. Nitric oxide activates cytosolic GUANYLATE CYCLASE and thus elevates intracellular levels of CYCLIC GMP.	Endogenous Nitrate Vasodilator,Mononitrogen Monoxide,Nitric Oxide, Endothelium-Derived,Nitrogen Monoxide,Endothelium-Derived Nitric Oxide,Monoxide, Mononitrogen,Monoxide, Nitrogen,Nitrate Vasodilator, Endogenous,Nitric Oxide, Endothelium Derived,Oxide, Nitric,Vasodilator, Endogenous Nitrate
D011652	Pulmonary Circulation	The circulation of the BLOOD through the LUNGS.	Pulmonary Blood Flow,Respiratory Circulation,Circulation, Pulmonary,Circulation, Respiratory,Blood Flow, Pulmonary,Flow, Pulmonary Blood,Pulmonary Blood Flows
D001794	Blood Pressure	PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.	Systolic Pressure,Diastolic Pressure,Pulse Pressure,Pressure, Blood,Pressure, Diastolic,Pressure, Pulse,Pressure, Systolic,Pressures, Systolic
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D000860	Hypoxia	Sub-optimal OXYGEN levels in the ambient air of living organisms.	Anoxia,Oxygen Deficiency,Anoxemia,Deficiency, Oxygen,Hypoxemia,Deficiencies, Oxygen,Oxygen Deficiencies
D001120	Arginine	An essential amino acid that is physiologically active in the L-form.	Arginine Hydrochloride,Arginine, L-Isomer,DL-Arginine Acetate, Monohydrate,L-Arginine,Arginine, L Isomer,DL Arginine Acetate, Monohydrate,Hydrochloride, Arginine,L Arginine,L-Isomer Arginine,Monohydrate DL-Arginine Acetate
D013552	Swine	Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).	Phacochoerus,Pigs,Suidae,Warthogs,Wart Hogs,Hog, Wart,Hogs, Wart,Wart Hog
D014661	Vasoconstriction	The physiological narrowing of BLOOD VESSELS by contraction of the VASCULAR SMOOTH MUSCLE.	Vasoconstrictions
D019331	NG-Nitroarginine Methyl Ester	A non-selective inhibitor of nitric oxide synthase. It has been used experimentally to induce hypertension.	L-NAME,N omega-Nitro-L-arginine Methyl Ester,NG-Nitro-L-Arginine Methyl Ester,N(G)-Nitro-L-arginine Methyl Ester,N(G)-Nitroarginine Methyl Ester,N(omega)-Nitro-L-arginine Methyl Ester,NG-Nitroarginine Methyl Ester, D-Orn-Isomer,NG-Nitroarginine Methyl Ester, L-Orn-Isomer, Monohydrochloride,Methyl Ester, NG-Nitro-L-Arginine,Methyl Ester, NG-Nitroarginine,N omega Nitro L arginine Methyl Ester,NG Nitro L Arginine Methyl Ester,NG Nitroarginine Methyl Ester,NG Nitroarginine Methyl Ester, D Orn Isomer