Mechanisms of the Flare Reaction in Human Skin

Abstract

The diffuse area of arteriolar vasodilation surrounding a region of recently injured human skin (axon reflex flare) is dependent upon the integrity of nerve fibers with cell bodies located in dorsal root ganglia. Evidence is presented to indicate that a vasodilator peptide similar to a kinin, neurotensin, or substance P, is implicated in the chain of biochemical events responsible for the transient shift in vascular tonus observable as the flare reaction.

Dense innervation of Deiters' and Hensen's cells persists after chronic deefferentation of guinea pig cochleas

“…Such a suggestion is interesting in light of the existing evidence that the type II contacts with OHCs in primates form reciprocal synapses with characteristics of both afferent and efferent transmission (Nadol, 1981;Nadol and Burgess, 1990). The local circuitry of axon reflexes is also well described in the somatic nervous system, where it is responsible for the flare reaction of the skin (Chapman, 1977). Furthermore, the axon reflex is discussed as one mechanism for asthma in humans and probably plays a role in bronchial tree constriction in the guinea pig (Verleden, 1996).…”

Acute transient thyroid swelling following needle biopsy: An update

“…Lowered pain threshold in the involved area, action of inflammatory-vasoactive substances and vasodilation are the key-elements of this reaction. 14 Increased density of mast cells, a known source of vasoactive mediators, has been reported in human thyroid cancer, 15 although their abundance has not been explored in benign thyroid nodules. In support of this hypothesis, ultrasonographically enlarged intrathyroidal vessels with no sign of hemorrhage was described in one of the cases.…”

Radial artery spasm: Should we worry?

“…Possibly, sympathetic drive is simply a sympathetic postganglionic neuron ''local response'' that does not involve a classic afferent-efferent reflex arc, analogous to the cutaneous flare reaction secondary to the release of vasoactive substances from afferent axon terminals. 18 Of interest, RAS does not seem to be counter-regulated by sympathetic escape -a functional sympatholysis that may be observed in a variety of vascular networks during prolonged sympathetic stimulation. 19 Although radial nerve blockade, as described by Bhakta and Zaheer, 1 is a relatively simple solution to arterial linerelated RAS, an effective treatment may also be achieved with intra-arterial injection of vasodilators.…”

“…La stimulation sympathique et possiblement due à une simple « réponse locale » d'un neurone sympathique post ganglionnaire sans impliquer l'arc réflexe classique afférent -efférent, étant en cela analogue à une réaction de vasodilatation cutanée secondaire à la libération de substances vasoactives par la terminaison des axones afférents. 18 Il est intéressant de noter que le SAR ne semble pas être contre-régulé par un échappement sympathique, une sympatholyse fonctionnelle que l'on peut observer dans différents réseaux vasculaires au cours d'une stimulation sympathique prolongée. 19 Bien que le bloc du nerf radial, tel que décrit par Bhakta et Zaheer, 1 constitue une solution relativement simple au SAR liée au cathétérisme radial, un traitement efficace peut également être obtenu par l'injection intra-artérielle de vasodilatateurs.…”