Referenced in: none

Automatically associated channels: TRP , TRPV , TRPV1

Title: Role of TRPV1 and P2X receptors in the activation of lung vagal C-fiber afferents by inhaled cigarette smoke in rats.

Authors: Wen-Hui Weng, Chun-Chun Hsu, Ling-Ling Chiang, Yi-Jiun Peter Lin, You Shuei Lin, Chien-Ling Su

Journal, date & volume: Mol Med Rep, 2013 Apr , 7, 1300-4

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/23443231

Abstract
Inhaled cigarette smoke (CS) triggers airway reflexes that are thought to result from the activation of lung vagal C-fiber afferents (LVCAs) via the action of reactive oxygen species in rats. We investigated the role of transient receptor potential vanilloid 1 (TRPV1) and P2X receptors in LVCA activation. Activities of LVCAs were recorded in anesthetized and artificially ventilated rats. Airway challenge of CS produced a concentration-dependent fiber stimulation. Pretreatment with dimethylthiourea [DMTU; a scavenger of hydroxyl radical (OH)], capsazepine (CPZ; a TRPV1 receptor antagonist) and iso-pyridoxalphosphate-6-azophenyl-2',5'-disulphonate (iso-PPADS; a P2X receptor antagonist) separately reduced the fiber responses by 64, 40 and 44%, respectively, whereas pretreatment with hexamethonium (a nicotinic acetylcholine receptor antagonist) failed to alter the response. A combination of CPZ and iso-PPADS exerted a greater inhibitory effect compared with the effect of either single pretreatment. However, a combination of DMTU, CPZ and iso-PPADS did not further reduce the fiber response compared with the combined effect of CPZ and iso-PPADS. It was concluded that both TRPV1 and P2X receptors, but not nicotinic acetylcholine receptors, participate in the stimulation of LVCAs by inhaled CS, possibly through the action of OH.