Bradykinin is degraded in hypoxic lungs and does not affect epithelial permeability
To investigate the effect of intravenous infusions of bradykinin (BK) on the permeability of the hypoxic pulmonary epithelium to small solutes, experiments (n = 7) were performed in yearling sheep with chronic vascular catheters. Sheep were anesthetized, intubated, paralyzed, and ventilated. After establishing stable and normal base-line pulmonary hemodynamics and blood gas tensions, the lungs were insufflated with a submicronic aerosol of technetium-/sup 99m/-labeled diethylenetriaminepentaacetate (/sup 99m/Tc-DTPA, mol wt = 492). Radioactivity arising from the right hemithorax was measured by an NaI probe with a parallel-holed collimator. The base-line pulmonary clearance rate (k) for /sup 99m/Tc-DTPA was 0.51 +/- 0.09% (SE)/min, while the sheep were ventilated with a fractional concentration of inspired O2 (FIO2) of 0.5 (arterial partial pressure of O2 (PaO2) = 196 +/- 11.4 (SE) Torr). Clearance of 99mTc-DTPA was unaffected by hypoxia alone or BK infusions in nonhypoxic lungs. The combination of an intravenous infusion of BK at either 1.2 (n = 3) or 2.4 micrograms . kg-1 . min-1 (n = 4) and alveolar hypoxia (FIO2 = 0.11, PaO2 = 28 +/- 1.6 (SE) Torr) did not affect pulmonary clearance of 99mTc-DTPA (k = 0.43 +/- 0.08% (SE)/min). In contrast, a 0.05-ml/kg intravenous infusion of oleic acid increased clearance 10-fold in one sheep. During combined hypoxia and BK infusion the pulmonary arterial BK concentration (radioimmunoassay) increased from 0.82 +/- 0.16 (SE) to 7.05 +/- 1.86 ng/ml (P less than 0.001), but the systemic arterial concentrations were unchanged (0.67 +/- 0.19 (SE) to 0.66 +/- 0.09 ng/ml).
- Research Organization:
- McMaster Univ. Health Sciences Centre, Hamilton, Ontario, Canada
- OSTI ID:
- 6332778
- Journal Information:
- J. Appl. Physiol.; (United States), Journal Name: J. Appl. Physiol.; (United States) Vol. 4; ISSN JAPYA
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
ANIMAL TISSUES
ANIMALS
ANOXIA
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
BRADYKININ
CARBOXYLIC ACIDS
CHELATING AGENTS
CLEARANCE
DOMESTIC ANIMALS
DRUGS
DTPA
EPITHELIUM
EXCRETION
HOURS LIVING RADIOISOTOPES
IMMUNOLOGY
INTERMEDIATE MASS NUCLEI
ISOMERIC NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KININS
LUNG CLEARANCE
LUNGS
MAMMALS
METABOLISM
MONOCARBOXYLIC ACIDS
NUCLEI
ODD-EVEN NUCLEI
OLEIC ACID
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PEPTIDES
PERMEABILITY
POLYPEPTIDES
PROTEINS
RADIOASSAY
RADIOIMMUNOASSAY
RADIOIMMUNOLOGY
RADIOISOTOPES
RADIOPROTECTIVE SUBSTANCES
RESPIRATORY SYSTEM
RUMINANTS
SHEEP
TECHNETIUM 99
TECHNETIUM ISOTOPES
TISSUES
TRACER TECHNIQUES
VERTEBRATES
YEARS LIVING RADIOISOTOPES