Investigating the Molecules, Cells, and Circuits for Aversive Taste Signaling

Research involving taste dysfunction in normal adults and adults with neurodegenerative diseases such as Alzheimer's throughout the years has pointed out the possibility of taste loss developing. It has also been pointed out how vital taste recognition and differentiation is for survival, specifically tastes such as bitter and sour. These tastes are known as "aversive" because they are those which the body usually rejects since they can be toxic or poisonous substances. Bitter substances are recognized by GPCRs which are comprised of a family of about 30 T2Rs. Whereas sour substances are ionic and are transduced via proton current which is recognized by the channel Otopetrin (Otop 1). Additionally, a study by Zhang et al. 2019 found that there are clusters of neurons that specifically mediate a single taste such as Penk does for sour which also responded to taste stimuli when citric acid was applied to the tongue. We therefore focus on the various concepts of aversive taste signaling. Our first aim was to discover if there was any taste dysfunction noted in APP/PS1 mouse models for which we used behavioral as well as immunohistochemical analysis. Our second aim was to find whether the antibody gustducin (GNAT3) could be a specific marker for bitter taste receptor cells. Our third aim was to discover if there was any specificity present in Penk-Cre tdTomato injected mice in order to prove or disprove the labelled-line hypothesis.