Presentation Details
| OTOP1 Mediates Chorda Tympani and Behavioral Responses to Ammonium Chloride (NH4Cl) Courtney E Wilson1, Ziyu Liang2, Bouchuan Teng3, Emily R Liman2, Sue C Kinnamon1. 1University of Colorado School of Medicine, Aurora, CO, USA.2University of Southern California, Los Angeles, CA, USA.3Caltech, Pasadena, CA, USA |
Abstract
Ammonium Chloride (NH4Cl) has been commonly used as a taste stimulus in gustatory vertebrate animal research for decades. Despite its prevalence, the mechanism by which it activates the gustatory system has been relatively unexamined. Here we present data indicating the involvement of sour receptor OTOP1 in the gustatory response to NH4Cl in mice. OTOP1 is a proton-selective channel expressed in Type III taste cells in mice. Chorda Tympani nerve responses to NH4Cl are greatly reduced or eliminated in mice lacking functional OTOP1 channels (Otop1-/- mice) as compared to wild-type littermates. Behaviorally, NH4Cl is an aversive stimulus to wild-type mice, eliciting increased avoidance as the concentration rises. In Otop1-/- mice, this avoidance is attenuated. When both OTOP1 and Type II taste receptor cells (those that respond to bitter, sweet, or umami stimuli) are eliminated in a double knockout Otop1-/-, Skn-1a-/- mouse line, behavioral avoidance of NH4Cl is abolished entirely. These data demonstrate that the sour receptor OTOP1, in addition to responding to acidic compounds, also mediates a large portion of the taste response to NH4Cl. How Type III cells and OTOP1 might differentially mediate responses to such disparate sensory stimuli as acids, water (Zocchi et al., 2017), and now ammonium remains a mystery.
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No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author.