Neurogenic vasodilation in the rat hairy skin measured using a laser Doppler flowmeter

Intradermal stimulation of the saphenous nerve of anesthetized rats at C-fiber strength elicited stimulus-dependent vasodilator responses in saphenous-innervated hairy skin. A laser Doppler flowmeter (Periflux, Pf1d) was used to measure these neurovascular responses non-invasively. Capsaicin pretreatment significantly attenuated the vasodilator response. Furthermore, intraperitoneal administration of atropine or mepyramine significantly reduced the skin vascular responses. The responses of halothane-anesthetized rats were significantly attenuated when compared with rats anesthetized with pentobarbitone. Results of this study suggest the presence of endothelium-dependent vasodilator peptidergic, cholinergic and histaminergic contributions to electrically-evoked axon reflex vasodilation in the rat hairy skin.