▁channels , ▁as ▁it ▁seems ▁to ▁be ▁activ ated ▁by ▁a ▁large ▁number ▁of ▁no x ious ▁chemical s ▁found ▁in ▁many ▁plants , ▁food , ▁cos met ics ▁and ▁poll ut ants . ▁ ▁Activ ation ▁of ▁the ▁TR PA 1 ▁ion ▁channel ▁by ▁the ▁o live ▁oil ▁phen ol ic ▁comp ound ▁o le oc anth al ▁appears ▁to ▁be ▁responsible ▁for ▁the ▁p ung ent ▁or ▁" pe pp ery " ▁sens ation ▁in ▁the ▁back ▁of ▁the ▁thro at ▁caused ▁by ▁o live ▁oil . ▁ ▁Although ▁several ▁none lect roph il ic ▁agents ▁such ▁as ▁th ym ol ▁and ▁ment hol ▁have ▁been ▁reported ▁as ▁TR PA 1 ▁ag on ists , ▁most ▁of ▁the ▁known ▁activ ators ▁are ▁elect roph il ic ▁chemical s ▁that ▁have ▁been ▁shown ▁to ▁activ ate ▁the ▁TR PA 1 ▁re ceptor ▁via ▁the ▁formation ▁of ▁a ▁revers ible ▁c oval ent ▁bond ▁with ▁c yst e ine ▁resid ues ▁present ▁in ▁the ▁ion ▁channel . ▁For ▁a ▁broad ▁range ▁of ▁elect roph il ic ▁agents , ▁chemical ▁react ivity ▁in ▁combination ▁with ▁a ▁lip oph il icity ▁en abling ▁memb rane ▁per me ation ▁is ▁cru cial ▁to ▁TR PA 1 ▁ag on istic ▁effect . ▁A ▁di ben z [ b , f ][ 1 , 4 ] ox az ep ine ▁derivative ▁subst it uted ▁by ▁a ▁car box y lic ▁m eth yl ester ▁at ▁position ▁ 1 0 ▁is ▁the ▁most ▁pot ent ▁TR PA 1 ▁ag