Time-dependently enhanced pressor responses in rat lungs after chronic exposure to high altitude.
To investigate the de-acclimatization process with respect to pulmonary vasoreactivity after high-altitude exposure, we performed a study of changes in pressor responses over time in salt-perfused lungs from rats that had been exposed to high altitude (HA, n = 41, 20 weeks at actual 2400 m). Comparisons were made with the lungs of rats kept at low altitude (n = 8, kept at 610 m). We studied HA rats from the time just after removal from high altitude to 2 weeks after the exposure. The pressor responses of HA lungs to both 0.5 microgram-angiotensin II and 5 min airway hypoxia (3% O2) just after the exposure did not differ from those of controls, but their responses began to increase within 12 h, and reached a maximum 3 days after exposure ended. The increase was time-dependent. We conclude that pulmonary vasopressor responses are enhanced time-dependently during the very early stages of de-acclimatization after high-altitude exposure.
Asano
K
K
Department of Environmental Physiology, Shinshu University School of Medicine, Matsumoto, Japan.
Sakai
A
A
D000531:Altitude; D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000502:physiology*; D006352:Heart Ventricles / Q000473:pathology / Q000503:physiopathology; D006400:Hematocrit; D000860:Hypoxia / Q000503:physiopathology; D008297:Male; D009929:Organ Size / Q000502:physiology; D011652:Pulmonary Circulation / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
D000804:Angiotensin II