title: Fetal ethanol exposure attenuates aversive oral effects of TrpV1, but not TrpA1 agonists in rats.
abstract: In humans, fetal ethanol exposure is highly predictive of adolescent ethanol use and abuse. Prior work in our labs indicated that fetal ethanol exposure results in stimulus-induced chemosensory plasticity in the taste and olfactory systems of adolescent rats. In particular, we found that increased ethanol acceptability could be attributed, in part, to an attenuated aversion to ethanol's aversive odor and quinine-like bitter taste quality. Here, we asked whether fetal ethanol exposure also alters the oral trigeminal response of adolescent rats to ethanol. We focused on two excitatory ligand-gated ion channels, TrpV1 and TrpA1, which are expressed in oral trigeminal neurons and mediate the aversive orosensory response to many chemical irritants. To target TrpV1, we used capsaicin, and to target TrpA1, we used allyl isothiocyanate (or mustard oil). We assessed the aversive oral effects of ethanol, together with capsaicin and mustard oil, by measuring short-term licking responses to a range of concentrations of each chemical. Experimental rats were exposed in utero by administering ethanol to dams through a liquid diet. Control rats had ad libitum access to an iso-caloric iso-nutritive liquid diet. We found that fetal ethanol exposure attenuated the oral aversiveness of ethanol and capsaicin, but not mustard oil, in adolescent rats. Moreover, the increased acceptability of ethanol was directly related to the reduced aversiveness of the TrpV1-mediated orosensory input. We propose that fetal ethanol exposure increases ethanol avidity not only by making ethanol smell and taste better, but also by attenuating ethanol's capsaicin-like burning sensations.
authors.affiliation: Department of Biology, Barnard College, Columbia University, New York, NY 10027, USA. jglendinning@barnard.edu
authors.forename: John I
authors.initials: JI
authors.lastname: Glendinning
authors.forename: Yael M
authors.initials: YM
authors.lastname: Simons
authors.forename: Lisa
authors.initials: L
authors.lastname: Youngentob
authors.forename: Steven L
authors.initials: SL
authors.lastname: Youngentob
mesh_terms: D000437:Alcoholism / Q000378:metabolism / Q000503:physiopathology; D000818:Animals; D002211:Capsaicin / Q000494:pharmacology; D002492:Central Nervous System Depressants / Q000009:adverse effects*; D000431:Ethanol / Q000009:adverse effects*; D005260:Female; D007509:Irritants / Q000494:pharmacology*; D009149:Mustard Plant; D010938:Plant Oils / Q000494:pharmacology; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000378:metabolism / Q000503:physiopathology*; D051381:Rats; D020318:Rats, Long-Evans; D000074025:TRPA1 Cation Channel; D050052:TRPC Cation Channels / Q000819:agonists*; D050916:TRPV Cation Channels / Q000819:agonists*; D014276:Trigeminal Nerve / Q000378:metabolism
chemical_list: D002492:Central Nervous System Depressants; D007509:Irritants; D010938:Plant Oils; D000074025:TRPA1 Cation Channel; D050052:TRPC Cation Channels; D050916:TRPV Cation Channels; C480976:Trpa1 protein, rat; C493922:Trpv1 protein, rat; D000431:Ethanol; D002211:Capsaicin; C027793:mustard oil