Role of sympathetic nerves in the vascular effects of local temperature in human forearm skin

P. E. Pergola, D. L. Kellogg, J. M. Johnson, W. A. Kosiba, D. E. Solomon

Research output: Contribution to journalArticle

175 Scopus citations

Abstract

The role of adrenergic nerve function in the cutaneous vascular response to changes in local skin temperature in the human forearm was examined using three protocols: 1) blocking release of norepinephrine presynaptically by local iontophoresis of bretylium (BT), 2) altering background adrenergic tone by changing whole body skin temperature, and 3) blocking cutaneous nerves by proximal infiltration of local anesthetic. Forearm skin blood flow was measured by laser-Doppler flowmetry (LDF) and cutaneous vascular conductance (CVC) was calculated as LDF/blood pressure. In protocol 1, local cooling (29°C) elicited a rapid and sustained fall in CVC at control sites (-43 ± 8%) in contrast to a biphasic response at BT-treated sites, consisting of an initial vasodilation followed by a vasoconstriction (percent change CVC = 28 ± 13 and -34 ± 18, respectively). Local warming (39°C) increased CVC at control and at BT-treated sites by 331 ± 46 and 139 ± 31%, respectively. In protocol 2, at a neutral, cool, or warm whole body skin temperature, local cooling (29°C) elicited similar reductions in CVC (-34 ± 8, -29 ± 5, and - 30 ± 4%, respectively), and local warming (38°C) produced similar increases in CVC (89 ± 15, 85 ± 21, and 74 ± 22%, respectively). In protocol 3, blocking cutaneous nerves did not affect either the vasoconstriction produced by local cooling to 29°C (CVC = -29 ± 12%, control; cutaneous nerve block = -41 ± 5%) or the vasodilator response to local warming to 39°C (increase in CVC, 320 ± 69%, control; cutaneous nerve block = 311 ± 42%). Our results suggest that 1) intact adrenergic nerve terminals and norepinephrine release, but not sympathetic nerve activity per se, are required for the immediate vasoconstrictor response to local cooling; 2) norepinephrine release can be locally initiated, perhaps through an axon reflex; 3) responses to prolonged local cooling involve mostly nonadrenergic mechanisms; and 4) the majority of the vasodilator response to local warming does not require an intact adrenergic system.

Original languageEnglish (US)
Pages (from-to)H785-H792
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume265
Issue number3 34-3
DOIs
StatePublished - 1993

Keywords

  • axon reflex
  • bretylium
  • iontophoresis
  • laser-Doppler flowmetry
  • nerve block
  • skin blood flow
  • thermoregulatory reflexes
  • vasoconstriction
  • vasodilation

ASJC Scopus subject areas

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

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