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TRPV‐1 channels contribute to local and reflex cutaneous vasodilation in humans
Author(s) -
Wong Brett J.,
Fieger Sarah M.,
Ade Carl J.
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.991.21
Subject(s) - vasodilation , trpv , microdialysis , axon reflex , reflex , medicine , anesthesia , chemistry , endocrinology , trpv1 , transient receptor potential channel , central nervous system , receptor
TRPV‐1 channels are putative channels in afferent sensory nerves. The purpose of this project was to determine the contribution of TRPV‐1 channels to cutaneous vasodilation elicited via local heating (LH) and whole body heating (WBH). In 2 separate protocols , subjects were equipped with 2 microdialysis fibers on the forearm: saline (control; CON) or 20 mM capsazepine (CPZ), a selective TRPV‐1 antagonist. Systemic arterial pressure (SAP) was measured and skin blood flow (SkBF) was monitored via laser‐Doppler flowmetry (LDF). In protocol 1, CPZ was infused for at least 1 hour after which local vasodilation was elicited in both sites via LH from 32°C to 40°C (0.5°C/5 sec). In protocol 2, CPZ was infused for at least 1 hour after which subjects underwent WBH via water‐perfused suits sufficient to raise oral temperature 1.0°C above baseline and elicit reflex vasodilation. At the end of each protocol, maximal SkBF was achieved via LH to 43°C and infusion of 28 mM nitroprusside. Cutaneous vascular conductance (CVC) was calculated (LDF/SAP) and normalized to maximal SkBF. In protocol 1, CPZ attenuated the initial peak to LH compared to CON (45±3 vs. 78±4 %CVCmax) as well as the secondary plateau phase (35±2 vs. 82±4 %CVCmax). In protocol 2, CPZ attenuated the SkBF response to WBH compared to CON (51±4 vs. 68±4 %CVCmax). These data indicate TRPV‐1 channels contribute to local vasodilation elicited via LH as well as reflex‐mediated vasodilation elicited via WBH.