Cholinergic mechanisms of cutaneous active vasodilation during heat stress in cystic fibrosis

D. L. Kellogg, G. J. Hodges, C. R. Orozco, T. M. Phillips, J. L. Zhao, J. M. Johnson

Research output: Contribution to journalArticle

13 Scopus citations

Abstract

To test the hypothesis that cutaneous active vasodilation in heat stress is mediated by a redundant cholinergic cotransmitter system, we examined the effects of atropine on skin blood flow (SkBF) increases during heat stress in persons with (CF) and without cystic fibrosis (non-CF). Vasoactive intestinal peptide (VIP) has been implicated as a mediator of cutaneous vasodilation in heat stress. VIP-containing cutaneous neurons are sparse in CF, yet SkBF increases during heat stress are normal. In CF, augmented ACh release or muscarinic receptor sensitivity could compensate for decreased VIP; if so, active vasodilation would be attenuated by atropine in CF relative to non-CF. Atropine was administered into skin by iontophoresis in seven CF and seven matched non-CF subjects. SkBF was monitored by laser-Doppler flowmetry (LDF) at atropine treated and untreated sites. Blood pressure [mean arterial pressure (MAP)] was monitored (Finapres), and cutaneous vascular conductance was calculated (CVC = LDF/MAP). The protocol began with a normothermic period followed by a 3-min cold stress and 30-45 min of heat stress. Finally, LDF sites were warmed to 42°C to effect maximal vasodilation. CVC was normalized to its site-specific maximum. During heat stress, CVC increased in both CF and non-CF (P < 0.01). CVC increases were attenuated by atropine in both groups (P < 0.01); however, the responses did not differ between groups (P = 0.99). We conclude that in CF there is not greater dependence on redundant cholinergic mechanisms for cutaneous active vasodilation than in non-CF.

Original languageEnglish (US)
Pages (from-to)963-968
Number of pages6
JournalJournal of applied physiology
Volume103
Issue number3
DOIs
StatePublished - Sep 1 2007

Keywords

  • Acetylcholine
  • Human
  • Skin blood flow
  • Thermoregulation
  • Vasoactive intestinal peptide

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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