The long-term objectives of this proposal are twofold: (1) to identify neurotransmitters released from taste bud cells during gustatory stimulation and (2) to investigate signal processing within the taste bud. These both are significant unanswered questions in the field of chemosensory reception. To date, there is only indirect evidence for candidate neurotransmitters in taste cells, including serotonin, glutamate, norepinephrine, acetylcholine, ATP, and peptides. We have developed a novel methodology to identify the neurotransmitter(s) released from mouse taste buds during gustatory stimulation. Our methodology uses Chinese Hamster Ovary (CHO) cells stably expressing high affinity receptors for candidate neurotransmitters and loaded with the calcium-sensitive dye, Fura 2.
The specific aims i nclude investigating whether taste stimulation elicits release of serotonin, norepinephrine, acetylcholine, glutamate, ATP, CCK, and VIP from taste buds. Further, we aim to investigate whether such release is mediated by Ca2+ influx, intracellular Ca2* release, or via transporter mediated mechanisms. We also will study whether gap junctions mediate signal transfer between taste cells during taste stimulation. The project will illuminate information processing in peripheral taste organs and may solve the conundrum of if/how signals generated in one cell (receptor cells) are transmitted to other cells (output cells) in the taste bud. The results may resolve the dilemma that taste cells appear to express a limited set of taste receptors (i.e. bitter, or sweet GPCRs, but not both) yet some taste cells and many sensory afferent nerve fibers respond to multiple taste stimuli: signals generated in dedicated receptor cells are transmitted to other (output) cells and integrated within processing units prior to the final output from the taste bud. ? ? ?

National Institute of Health (NIH)
National Institute on Deafness and Other Communication Disorders (NIDCD)
Research Project (R01)
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Somatosensory and Chemosensory Systems Study Section (SCS)
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Davis, Barry
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University of Miami School of Medicine
Schools of Medicine
United States
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Roper, Stephen D; Chaudhari, Nirupa (2017) Taste buds: cells, signals and synapses. Nat Rev Neurosci 18:485-497
Dando, Robin; Pereira, Elizabeth; Kurian, Mani et al. (2015) A permeability barrier surrounds taste buds in lingual epithelia. Am J Physiol Cell Physiol 308:C21-32
Meredith, Tricia L; Corcoran, Alan; Roper, Stephen D (2015) Leptin's effect on taste bud calcium responses and transmitter secretion. Chem Senses 40:217-22
Roper, Stephen D (2015) The taste of table salt. Pflugers Arch 467:457-63
Roper, Stephen D (2014) Sensory end-organs: signal processing in the periphery: a symposium presented at the 2013 Annual Meeting of the Society for Neuroscience, San Diego, CA, USA. J Physiol 592:3383-5
Roper, Stephen D (2014) TRPs in taste and chemesthesis. Handb Exp Pharmacol 223:827-71
Roper, Stephen D (2013) Taste buds as peripheral chemosensory processors. Semin Cell Dev Biol 24:71-9
Roper, Stephen D (2013) Introduction to signal processing in peripheral sensory organs. Semin Cell Dev Biol 24:1-2
Dando, Robin; Roper, Stephen D (2012) Acetylcholine is released from taste cells, enhancing taste signalling. J Physiol 590:3009-17
Dando, Robin; Dvoryanchikov, Gennady; Pereira, Elizabeth et al. (2012) Adenosine enhances sweet taste through A2B receptors in the taste bud. J Neurosci 32:322-30

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