期刊
AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY
卷 286, 期 6, 页码 H2113-H2117出版社
AMER PHYSIOLOGICAL SOC
DOI: 10.1152/ajpheart.01054.2003
关键词
baroreceptors; blood pressure; antioxidants
资金
- NCRR NIH HHS [RR 00051] Funding Source: Medline
- NHLBI NIH HHS [HL 67624] Funding Source: Medline
- NIA NIH HHS [AG 13038, AG 19365, AG 06537] Funding Source: Medline
Cardiovagal baroreflex sensitivity (BRS) declines with advancing age in healthy men. We tested the hypothesis that oxidative stress contributes mechanistically to this age-associated reduction. Eight young (23 +/- 1 yrs, means +/- SE) and seven older (63 +/- 3) healthy men were studied. Cardiovagal BRS was assessed using the modified Oxford technique (bolus infusion of 50-100 mug sodium nitroprusside, followed 60 s later by a 100- to 150-mug bolus of phenylephrine hydrochloride) in triplicate at baseline and during acute intravenous ascorbic acid infusion. At baseline, cardiovagal BRS ( slope of the linear portion of the R-R interval-systolic blood pressure relation during pharmacological changes in arterial blood pressure) was 56% lower (P < 0.01) in older (8.3 +/- 1.6 ms/mmHg) compared with young (19.0 +/- 3.1 ms/mmHg) men. Ascorbic acid infusion increased plasma concentrations similarly in young (62 +/- 9 vs. 1,249 +/- 72 mu mol/l for baseline and during ascorbic acid; P < 0.05) and older men (62 +/- 4 vs. 1,022 +/- 55 mumol/l; P < 0.05) without affecting baseline blood pressure, heart rate, carotid artery compliance, or the magnitude of change in systolic blood pressure in response to bolus sodium nitroprusside and phenylephrine hydrochloride infusion. Ascorbic acid ( vitamin C) infusion increased cardiovagal BRS in older (Delta 58 +/- 16%; P < 0.01), but not younger (Delta - 4 +/- 4%) men. These data provide experimental support for the concept that oxidative stress contributes mechanistically to age-associated reductions in cardiovagal BRS in healthy men.
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