Umami Responses in Mouse Taste Cells Indicate More than One Receptor

Maruyama, Yutaka; Pereira, Elizabeth; Margolskee, Robert F.; Chaudhari, Nirupa; Roper, Stephen D.

doi:10.1523/jneurosci.4329-05.2006

Cited by 134 publications

(100 citation statements)

References 46 publications

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“…Individual tastants were 30 M cycloheximide, 200 M denatonium, 500 mM sucrose, 100 M SC45647, 200 mM MPG plus 1 mM IMP, 500 mM NaCl, and 100 mM citric acid. These concentrations were selected based on previous studies showing that they produce robust and reliable calcium responses (Caicedo et al, 2002;Richter et al, 2003;Maruyama et al, 2006). All tastant solutions (except citric acid) contained 2 M fluorescein to monitor stimulus application, duration, and concentration.…”

Section: Methodsmentioning

confidence: 99%

Breadth of Tuning and Taste Coding in Mammalian Taste Buds

Tomchik¹,

Berg²,

Kim³

et al. 2007

J. Neurosci.

221

270

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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.

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Section: Methodsmentioning

confidence: 99%

Breadth of Tuning and Taste Coding in Mammalian Taste Buds

Tomchik¹,

Berg²,

Kim³

et al. 2007

J. Neurosci.

221

270

View full text Add to dashboard Cite

show abstract

“…Neurons in this region respond not only to each of the four classical prototypical tastes sweet, salt, bitter and sour (14,21) but also to umami tastants such as glutamate (which is present in many natural foods such as tomatoes, mushrooms and milk) (15) and inosine monophosphate (which is present in meat and some fish such as tuna) (16) . This evidence, taken together with the identification of glutamate taste receptors (22,23) , leads to the view that there are five prototypical types of taste information channels, with umami contributing, often in combination with corresponding olfactory inputs (24)(25)(26) to the flavour of protein. In addition, other neurons respond to water and others to somatosensory stimuli including astringency as exemplified by tannic acid (27) and capsaicin (28,29) .…”

Section: The Secondary Taste Cortexmentioning

confidence: 99%

Taste, olfactory and food texture reward processing in the brain and the control of appetite

Rolls

2012

Proc. Nutr. Soc.

106

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Complementary neuronal recordings and functional neuroimaging in human subjects show that the primary taste cortex in the anterior insula provides separate and combined representations of the taste, temperature and texture (including fat texture) of food in the mouth independently of hunger and thus of reward value and pleasantness. One synapse on, in the orbitofrontal cortex (OFC), these sensory inputs are for some neurons combined by learning with olfactory and visual inputs, and these neurons encode food reward in that they only respond to food when hungry, and in that activations correlate with subjective pleasantness. Cognitive factors, including word-level descriptions, and attention modulate the representation of the reward value of food in the OFC and a region to which it projects, the anterior cingulate cortex. Further, there are individual differences in the representation of the reward value of food in the OFC. It is argued that over-eating and obesity are related in many cases to an increased reward value of the sensory inputs produced by foods, and their modulation by cognition and attention that over-ride existing satiety signals. It is proposed that control of all rather than one or several of these factors that influence food reward and eating may be important in the prevention and treatment of overeating and obesity.

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“…Namely, Damak et al [98] recorded reduced but still appreciable nerve and behavioral responses to glutamate in T1R3-null mice. Maruyama et al [99] extended these studies by recording responses from individual taste cells in lingual slice preparations from mutant and wild-type mice. They also showed that although umami responses were somewhat diminished in T1R3-null mice, nonetheless, many cells responded to umami-taste stimulation.…”

Section: T2rs Are Gpc Receptors For Bitter Tastementioning

confidence: 99%

Signal transduction and information processing in mammalian taste buds

Roper

2007

Pflugers Arch - Eur J Physiol

272

215

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The molecular machinery for chemosensory transduction in taste buds has received considerable attention within the last decade. Consequently, we now know a great deal about sweet, bitter, and umami taste mechanisms and are gaining ground rapidly on salty and sour transduction. Sweet, bitter, and umami tastes are transduced by G-protein-coupled receptors. Salty taste may be transduced by epithelial Na channels similar to those found in renal tissues. Sour transduction appears to be initiated by intracellular acidification acting on acidsensitive membrane proteins. Once a taste signal is generated in a taste cell, the subsequent steps involve secretion of neurotransmitters, including ATP and serotonin. It is now recognized that the cells responding to sweet, bitter, and umami taste stimuli do not possess synapses and instead secrete the neurotransmitter ATP via a novel mechanism not involving conventional vesicular exocytosis. ATP is believed to excite primary sensory afferent fibers that convey gustatory signals to the brain. In contrast, taste cells that do have synapses release serotonin in response to gustatory stimulation. The postsynaptic targets of serotonin have not yet been identified. Finally, ATP secreted from receptor cells also acts on neighboring taste cells to stimulate their release of serotonin. This suggests that there is important information processing and signal coding taking place in the mammalian taste bud after gustatory stimulation.

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Umami Responses in Mouse Taste Cells Indicate More than One Receptor

Cited by 134 publications

References 46 publications

Breadth of Tuning and Taste Coding in Mammalian Taste Buds

Breadth of Tuning and Taste Coding in Mammalian Taste Buds

Taste, olfactory and food texture reward processing in the brain and the control of appetite

Signal transduction and information processing in mammalian taste buds

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