| タイトル | Post-suspension hypotension is attenuated in Sprague-Dawley rats by prostacyclin synthase inhibition |
| 著者（英） | Bayorh, M. A.; Eatman, D.; Emmett, N.; Socci, R. R.; Walton, M. |
| 発行日 | 2002-05-01 |
| 言語 | eng |
| 内容記述 | Cardiovascular deconditioning, sometimes manifested in astronauts during standing postflight, may be related to the impairment of autonomic function and/or excessive production of endothelium-dependent relaxing factors. In the present study, we examined the cardiovascular responses to 7-day 30 degrees tail-suspension and a subsequent 6-h post-suspension period in conscious male Sprague-Dawley rats to determine the role of prostacyclin in the observed post-suspension reduction in mean arterial pressure (MAP). The specific prostacyclin synthase inhibitor U-51605 (0.3 mg/kg), or saline, was administered intravenously prior to release from suspension and at 2 and 4 h post-suspension. During 7 days of suspension, MAP did not change, however, there was a post-suspension reduction in MAP which was associated with significant increases in plasma prostacyclin and nitric oxide. U-51605 attenuated the observed post-suspension hypotension and reduced plasma prostacyclin levels, but not nitric oxide levels. The baroreflex sensitivity for heart rate was modified by U-51605: increased MAP threshold and effective MAP range. Thus, the post-suspension reduction in mean arterial pressure may be due to overproduction of prostacyclin and/or other endothelium-dependent relaxing factors and alteration in baroreflex activity. |
| NASA分類 | Aerospace Medicine |
| 権利 | Copyright |
| URI | https://repository.exst.jaxa.jp/dspace/handle/a-is/302092 |
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