Dynamics of local pressure-induced cutaneous vasodilation in the human hand.
We recently demonstrated that a pressure-induced vasodilation results from local nonnociceptive stimulation of the skin of the human hand. We aimed to test the hypothesis that this vasodilation was not a short-lived response to a single type of pressure strain, but could be a widely activated and prolonged protective cutaneous response. We studied the dynamics of pressure-induced vasodilation during various ramp changes in local externally applied pressure using laser Doppler flowmetry. Changes from an adjacent control probe were subtracted from pressure-induced local changes. Following an initial transient decrease, continuous 4.4, 5.6, and 11.1 Pa.s(-1) increases of pressure resulted in a secondary increase of blood flow whose amplitude was maximal for 11.1 Pa.s(-1) (22.9 +/- 12.6% above baseline) (mean +/- SEM). The increase in flow was not noted at 16.7 Pa.s(-1). If the 16.7 Pa.s(-1) ramp pressure increase was interrupted at min 2 or 4, a prolonged vasodilation response was found, but not if it was stopped at min 8. When the 16.7 Pa.s(-1) increasing pressure was returned to zero after 4 min of pressure increase (-8.1 +/- 8.9% before pressure removal), vasodilation occurred and reached a maximum of 26.0 +/- 9.6% at 7 min after removal of pressure (P < 0.05 from baseline). Pressure-induced vasodilation is a slow-responding and transient adaptive phenomenon, initiated by a wide range of pressure changes below the range of noxious stimulation. We propose that this response is a protective mechanism without which certain pressure-associated lesions may develop.
Abraham
P
P
Laboratoire de Physiologie et d'Explorations Vasculaires, Centre Hospitalier Universitaire d'Angers, Angers Cedex 01, 49033, France.
Fromy
B
B
Merzeau
S
S
Jardel
A
A
Saumet
J L
JL
D000328:Adult; D001794:Blood Pressure; D005260:Female; D006225:Hand; D006439:Hemodynamics; D006801:Humans; D017078:Laser-Doppler Flowmetry; D008297:Male; D008833:Microcirculation / Q000502:physiology; D012867:Skin / Q000098:blood supply*; D014664:Vasodilation / Q000502:physiology