IJPPP Copyright © 2009-All rights reserved. Published by e-Century Publishing Corporation, Madison, WI 53711
Int J Physiol Pathophysiol Pharmacol 2013;5(3):148-160

Original Article
The effect of topical capsaicin-induced sensitization on heat-evoked cutaneous
vasomotor responses

Thomas A Nielsen, Larissa Bittencourt da Silva, Lars Arendt-Nielsen, Parisa Gazerani

Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Faculty of Medicine, Aalborg University,
Aalborg, Denmark

Received May 4, 2013; Accepted August 19, 2013; Epub September 10, 2013; Published September 15, 2013

Abstract: Brief, localized, cutaneous, non-painful thermal stimuli can evoke a transient vasomotor response, causing increased
cutaneous blood flow and elevated skin temperature. The aims of this study were to investigate 1) if cutaneous sensitization by topical
application of capsaicin (TRPV1 receptor agonist) can facilitate the size, duration and spatial extent of this vasomotor response and 2) if
males and females respond differently. Thermal pulses (43°C for 60 seconds) were applied on left/right volar forearms of 15
age-matched males and females. Skin temperature and cutaneous blood flow were measured 1, 5, 10, 15, and 30 minutes after heat
application before and after topical capsaicin (1%, 30 min application) with contralateral arm serving as the control. Recordings were
made from the region of interest at distances of 2, 4, 6, 8, and 10 cm from the capsaicin application site. Sensitization significantly
enhanced skin temperature for up to 30 min and compared with non-sensitized skin at 10 min. Females showed the strongest
response after sensitization, but the response lasted longer and spread more widely in males. The blood flow responses were
significantly longer after capsaicin (from 5 to 30 minutes after thermal application). This increased blood flow extended outside the
treated area up to 10 min after stimulation. After sensitization, the area under the blood flow response curves showed significantly
stronger responses in females, spreading 4 cm outside the stimulation site. Cutaneous sensitizing caused prolonged and spatially
expanded vasomotor responses to standardized thermal stimulation with sex specific differences. (IJPPP1305003).

Keywords: Neurogenic inflammation, vasomotor response, thermal stimulation, sensitization, capsaicin, cutaneous

Address correspondence to: Dr. Parisa Gazerani, Center for Sensory-Motor Interaction (SMI), Department of Health Science and
Technology, Faculty of Medicine, Aalborg University, Fredrik Bajers Vej 7-D3, DK-9220 Aalborg, Denmark. Tel: +45 99 40 24 12; Fax: +45
98 15 40 08; E-mail: gazerani@hst.aau.dk