| タイトル | WISE-2005: Adrenergic Responses Before and After 60 Days of 6 Degree Head-Down Bed-Rest in Women |
| 著者（英） | Greaves, D.; Hughson, R. L.; Custaud, M. A.; Dyson, K.; Arbeille, Ph.; Shoemaker, J. K.; Edgell, H.; Hughson, R. L. |
| 著者所属（英） | Waterloo Univ. |
| 発行日 | 2006-07-01 |
| 言語 | eng |
| 内容記述 | Sixteen women who participated in the WISE-2005 headdown bed rest (HDBR) were studied before and on day 56 of bed rest to test the hypothesis that chronic changes in circulating norepinephrine (NOR) would change the response to adrenergic receptor agonists. Five minute infusions of 2 doses of isoproterenol (ISO), and 2 doses of NOR were administered while heart rate (HR), mean arterial pressure (MAP) and total peripheral resistance (TPR) were measured. Before HDBR, the higher dose of ISO increased HR by 13 beats/min (P<O.OOl) and decreased TPR by -50% (P<O.OOl) with no changes in MAP, the higher dose of NOR increased MAP by 8 mmHg (P<O.OOl) and increased TPR -20% (P=0.007) with no change in HR. On HDBR day 56, subjects who took part in daily exercise+lower body negative pressure (EX+LBNP) countermeasures had no change in HR response to ISO while the control group (CON) had greater increases in HR. MAP tended to be lower post-HDBR in CON but not in EX+LBNP, while TPR was higher in both groups. In response to NOR, MAP increased with elevated TPR with no change in HR. Post-HDBR TPR increased more in the EX+LBNP group. These studies indicate that HDBR alters the HR response to IS0 but that EX+LBNP countermeasure prevented this change. The greater TPR response to NOR in the post-HDBR for the EX+LBNP group might reflect enhanced peripheral vasoconstrictor response that could reduce the risk of orthostatic intolerance after this countermeasure. |
| NASA分類 | Aerospace Medicine |
| 権利 | Copyright |
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