The dependence of taste buds on innervation has been used as a model to understand nerve/tar interactions. Loss of innervation results in a loss of the normal morphological appearance of taste buds, while restoration of innervation results in a recovery of taste bud morphology and function. The adult regenerating gustatory system is especially susceptible to environmental manipulations. Combining unilateral chorda tympani nerve section and low sodium diet in adult rats results in a variety of functional and anatomical alterations in both taste buds and in the regenerating nerve. Furthermore, functional and anatomical alterations also occur in the intact, contralateral side of the tongue. In addition to injury-induced effects related to the peripheral portion of the chorda tympani nerve, there are also extreme morphological changes that involve the central portion of the sectioned nerve. Coordinated studies will take advantage of the remarkable functional and anatomical plasticity induced by combined unilateral chorda tympani nerve section and dietary sodium restriction. A systems-level approach will focus on neural plasticity in the adult rat gustatory system. Combined anatomical, neurophysiological, electron microscopic, and immunocytochemical techniques will permit a determination of: 1) the stability of innervation of single taste buds over time in normal adults and determine the accuracy of chorda tympani neurons in reinnervating their original targets;2) the extent and nature of terminal field plasticity in the NTS;3) the extent and nature of synaptic plasticity in the NTS;and 4) the functional consequences of unilateral chorda tympani nerve section and/or dietary sodium restriction on taste responses in the NTS. Findings from these studies will address the broader topics of sensory coding, the role of neural activity in maintenance of sensory function, and the temporal stability and accuracy of peripheral innervation under normal circumstances and in response to nerve damage. Results will also enable a clearer understanding of the neurobiological sequelae of human taste nerve damage sustained pathologically, or during middle ear or oral surgery.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Research Project (R01)
Project #
3R01DC006938-05S1
Application #
7869061
Study Section
Somatosensory and Chemosensory Systems Study Section (SCS)
Program Officer
Davis, Barry
Project Start
2009-07-17
Project End
2010-06-30
Budget Start
2009-07-17
Budget End
2010-06-30
Support Year
5
Fiscal Year
2009
Total Cost
$144,039
Indirect Cost
Name
University of Virginia
Department
Psychology
Type
Schools of Arts and Sciences
DUNS #
065391526
City
Charlottesville
State
VA
Country
United States
Zip Code
22904
Sun, Chengsan; Krimm, Robin; Hill, David L (2018) Maintenance of Mouse Gustatory Terminal Field Organization is Dependent on BDNF at Adulthood. J Neurosci :
Skyberg, Rolf; Sun, Chengsan; Hill, David L (2017) Maintenance of Mouse Gustatory Terminal Field Organization Is Disrupted following Selective Removal of Peripheral Sodium Salt Taste Activity at Adulthood. J Neurosci 37:7619-7630
Meng, Lingbin; Huang, Tao; Sun, Chengsan et al. (2017) BDNF is required for taste axon regeneration following unilateral chorda tympani nerve section. Exp Neurol 293:27-42
Sun, Chengsan; Dayal, Arjun; Hill, David L (2015) Expanded terminal fields of gustatory nerves accompany embryonic BDNF overexpression in mouse oral epithelia. J Neurosci 35:409-21
Meng, Lingbin; Ohman-Gault, Lisa; Ma, Liqun et al. (2015) Taste Bud-Derived BDNF Is Required to Maintain Normal Amounts of Innervation to Adult Taste Buds. eNeuro 2:
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May, Olivia L; Erisir, Alev; Hill, David L (2007) Ultrastructure of primary afferent terminals and synapses in the rat nucleus of the solitary tract: comparison among the greater superficial petrosal, chorda tympani, and glossopharyngeal nerves. J Comp Neurol 502:1066-78
Guagliardo, Nick A; Hill, David L (2007) Fungiform taste bud degeneration in C57BL/6J mice following chorda-lingual nerve transection. J Comp Neurol 504:206-16