TY - JOUR
T1 - Breadth of tuning and taste coding in mammalian taste buds
AU - Tomchik, Seth M.
AU - Berg, Stephanie
AU - Joung, Woul Kim
AU - Chaudhari, Nirupa
AU - Roper, Stephen D.
PY - 2007/10/3
Y1 - 2007/10/3
N2 - A longstanding question in taste research concerns taste coding and, in particular, how broadly are individual taste bud cells tuned to taste qualities (sweet, bitter, umami, salty, and sour). Taste bud cells express G-protein-coupled receptors for sweet, bitter, or umami tastes but not in combination. However, responses to multiple taste qualities have been recorded in individual taste cells. We and others have shown previously there are two classes of taste bud cells directly involved in gustatory signaling: "receptor" (type II) cells that detect and transduce sweet, bitter, and umami compounds, and "presynaptic" (type III) cells. We hypothesize that receptor cells transmit their signals to presynaptic cells. This communication between taste cells could represent a potential convergence of taste information in the taste bud, resulting in taste cells that would respond broadly to multiple taste stimuli. We tested this hypothesis using calcium imaging in a lingual slice preparation. Here, we show that receptor cells are indeed narrowly tuned: 82% responded to only one taste stimulus. In contrast, presynaptic cells are broadly tuned: 83% responded to two or more different taste qualities. Receptor cells responded to bitter, sweet, or umami stimuli but rarely to sour or salty stimuli. Presynaptic cells responded to all taste qualities, including sour and salty. These data further elaborate functional differences between receptor cells and presynaptic cells, provide strong evidence for communication within the taste bud, and resolve the paradox of broad taste cell tuning despite mutually exclusive receptor expression.
AB - A longstanding question in taste research concerns taste coding and, in particular, how broadly are individual taste bud cells tuned to taste qualities (sweet, bitter, umami, salty, and sour). Taste bud cells express G-protein-coupled receptors for sweet, bitter, or umami tastes but not in combination. However, responses to multiple taste qualities have been recorded in individual taste cells. We and others have shown previously there are two classes of taste bud cells directly involved in gustatory signaling: "receptor" (type II) cells that detect and transduce sweet, bitter, and umami compounds, and "presynaptic" (type III) cells. We hypothesize that receptor cells transmit their signals to presynaptic cells. This communication between taste cells could represent a potential convergence of taste information in the taste bud, resulting in taste cells that would respond broadly to multiple taste stimuli. We tested this hypothesis using calcium imaging in a lingual slice preparation. Here, we show that receptor cells are indeed narrowly tuned: 82% responded to only one taste stimulus. In contrast, presynaptic cells are broadly tuned: 83% responded to two or more different taste qualities. Receptor cells responded to bitter, sweet, or umami stimuli but rarely to sour or salty stimuli. Presynaptic cells responded to all taste qualities, including sour and salty. These data further elaborate functional differences between receptor cells and presynaptic cells, provide strong evidence for communication within the taste bud, and resolve the paradox of broad taste cell tuning despite mutually exclusive receptor expression.
KW - Cell type
KW - Coding
KW - Presynaptic cell
KW - Receptor cell
KW - Taste bud
KW - Taste processing
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UR - http://www.scopus.com/inward/citedby.url?scp=35148813068&partnerID=8YFLogxK
U2 - 10.1523/JNEUROSCI.1863-07.2007
DO - 10.1523/JNEUROSCI.1863-07.2007
M3 - Article
C2 - 17913917
AN - SCOPUS:35148813068
VL - 27
SP - 10840
EP - 10848
JO - Journal of Neuroscience
JF - Journal of Neuroscience
SN - 0270-6474
IS - 40
ER -