| Co-Investigator(Kenkyū-buntansha) |
MATUMOTO Seiji SHINSHU UNIV., SCH.OF MED., ASOCIATE PROFESSOR, 医学部, 助教授 (40173893)
SAITO Muneo JIKKENDOUBUTU-CHUOU-KENKYUJYO CHAREMAN, 室長 (50167417)
TAKEOKA Michiko SHINSHU UNIV., SCH OF MED., ASSISTANT, 医学部, 助手 (30197280)
YANAGIDAIRA Yasunori SHINSHU UNIV., SCH OF MED., ASSISTANT PROFESSOR, 医学部, 講師 (10020760)
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| Research Abstract |
In this project, three studies were performed. First study was to investigate the comparison of susceptibility to high - altitude among three mammalian species. Adult male Sprague Dawley( SD,n=10 )rats, Suncs( n=5 )and Pika( n=6 )were used. The ratio of right to left ventricular weight ( RVW/LVW ), haematocrit ( Ht ) and smooth muscle in media of pulmonary arterioles in Pikas showed significantly low values compared with SD rats. But not differences were observed between SD rats and Suncs. Second, the comparison of susceptibility to high - altitude among rat strains were examined. In this study, six strains of rat i e LEW SSN( n=7 ), F344/N( n=7 ), WM/MS( N=3 ), WKAH/HOK( n=7 ), WF/N( n=3 )and SD( N=27 )were used. To investigate potential differences in lung vascular control among these six rat strains, we measured the pressure response to acute alveolar hypoxia(3%O_2 )or angiotensin 2 injection in isolated perfused lungs. As the result, F334/N showed smallest pressure response to acute alveolar hypoxia and WKAH/HOK showed biggest response to hypoxia. Third, to investigate the effects of cold - exposure on pulmonary pressure response to hypoxia, we studied pressure responses in perfused lungs from rat that had been exposed to a cold environment, and those kept at a normal temperature. The pressure responses of rat lungs to hypoxia just after removal from the cold were significantly lower than that control value, bat the responses began to increase within 12 hrs, and reached a maximum 3days after cessation of cold - exposure. The increase was time - dependent.
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