Nitric oxide and attenuated reflex cutaneous vasodilation in aged skin

Lacy A. Holowatz, Belinda L. Houghton, Brett J. Wong, Brad W. Wilkins, Aaron W. Harding, W. Larry Kenney, Christopher T. Minson

Research output: Contribution to journalArticlepeer-review

122 Scopus citations


Thermoregulatory cutaneous vasodilation is diminished in the elderly. The goal of this study was to test the hypothesis that a reduction in nitric oxide (NO)-dependent mechanisms contributes to the attenuated reflex cutaneous vasodilation in older subjects. Seven young (23 ± 2 yr) and seven older (71 ± 6 yr) men were instrumented with two microdialysis fibers in the forearm skin. One site served as control (Ringer infusion), and the second site was perfused with 10 mM NG-nitro-L-arginine methyl ester to inhibit NO synthase (NOS) throughout the protocol. Water-perfused suits were used to raise core temperature 1.0°C. Red blood cell (RBC) flux was measured with laser-Doppler flowmetry over each microdialysis fiber. Cutaneous vascular conductance (CVC) was calculated as RBC flux per mean arterial pressure, with values expressed as a percentage of maximal vasodilation (infusion of 28 mM sodium nitroprusside). NOS inhibition reduced CVC from 75 ± 6% maximal CVC (CVCmax) to 53 ± 3% CVCmax in the young subjects and from 64 ± 5% CVCmax to 29 ± 2% CVCmax in the older subjects with a 1.0°C rise in core temperature. Thus the relative NO-dependent portion of cutaneous active vasodilation (AVD) accounted for ∼23% of vasodilation in the young subjects and 60% of the vasodilation in the older subjects at this level of hyperthermia (P < 0.001). In summary, NO-mediated pathways contributed more to the total vasodilatory response of the older subjects at high core temperatures. This suggests that attenuated cutaneous vasodilation with age may be due to a reduction in, or decreased vascular responsiveness to, the unknown neurotransmitter(s) mediating AVD.

Original languageEnglish (US)
Pages (from-to)H1662-H1667
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Issue number5 53-5
StatePublished - May 1 2003
Externally publishedYes


  • Aging
  • Hyperthermia
  • Microdialysis
  • Skin blood flow
  • Thermoregulation

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)


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