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| Poster #324 Does sour stimulation inhibit responses to sweet stimuli in the mouse geniculate ganglion? |
| Isabella R. Fleites1, Gennady Dvoryanchikov1, Yuryanni A. Rodriguez1, Nirupa Chaudhari1,2, Stephen D. Roper1,2 1Dept. of Physiology and Biophysics Univ. of Miami Miller School of Medicine, Miami, FL, United States 2Dept. of Otolaryngology Univ. of Miami Miller School of Medicine, Miami, FL, United States |
The mouse geniculate ganglion receives input from taste buds of the anterior tongue and palate. It is hypothesized that in taste buds, sour-sensing Type III taste cells inhibit sweet-sensing Type II taste cells when a mixture of sour and sweet stimuli is applied. If this is the case, geniculate ganglion cells should respond less robustly to a mixture of sucrose/citric acid than to sucrose alone. Indeed, consistent with data from other laboratories, we found that adding 10 mM citric acid to 300 mM sucrose reduced responses in sucrose-sensing ganglion neurons to 30% (n=27 neurons, p<0.0001). KCl also stimulates sour-sensing Type III taste bud cells and leads to the release of inhibitory transmitters in taste buds. Thus, we reasoned that KCl, too, should reduce sucrose responses. However, inconsistent with the proposed hypothesis, adding KCl to sucrose (250 mM KCl/300 mM sucrose) did not alter the sucrose responses in sucrose-sensing ganglion neurons. Sucrose responses in the presence of KCl were 87% of the control values, which was not a significant difference (n = 30 neurons, p = 0.09). Thus, when recorded in the geniculate ganglion, the modulation of sweet responses by acidified sucrose may or may not arise from interactions between Type II and Type III cells in the taste bud. To further explore if activation of acid-sensing Type III taste bud cells alters responses at the level of the geniculate ganglion, we are currently testing whether NH4Cl ꟷanother taste stimulus for Type III taste cellsꟷinhibits sucrose responses in the ganglion. |