Perineural capsaicin treatment attenuates reactive hyperaemia in the rat skin

Abstract

The neural mechanisms of reactive cutaneous hyperaemia were studied by using a novel experimental approach: the simultaneous measurement of cutaneous blood flow by laser-Doppler flowmetry in adjacent innervated and chemodenervated skin regions of the rat hindpaw served by the same artery. Transient occlusion of the femoral artery (0.5–6 min) resulted in reactive hyperaemia that was greatly reduced in the chemodenervated region. After 3 min arterial occlusion, peak cutaneous blood flow was 109±13% vs. 53±7%* (% change from baseline, n=11, * P<0.05), and the total hyperaemic response was 110±21 vs. 52±12* (arbitrary perfusion units) in intact vs. chemodenervated skin regions, respectively. The findings provide clear evidence for the involvement of peptidergic capsaicin-sensitive afferent nerves in the mechanism of reactive cutaneous hyperaemia.