The Journal of Neuroscience, October 1, 2002, 22(19):8607-8613
Injury-Induced Functional Plasticity in the Peripheral
Gustatory System
Susan J.
Hendricks1,
Suzanne I.
Sollars2, and
David L.
Hill3
1 Bloedel Hearing Research Center, University of
Washington, Seattle, Washington 98195, 2 Department of
Psychology, University of Nebraska, Omaha, Nebraska 68182, and
3 Department of Psychology, University of Virginia,
Charlottesville, Virginia 22904
Combining unilateral denervation of anterior tongue taste buds with
a low-sodium diet in rats results in a rapid, dramatic, and selective
attenuation of neurophysiological sodium taste responses from the
intact side of the tongue. The transduction pathway responsible for the
attenuated response is through the epithelial sodium channel (Hill and
Phillips, 1994). Current experiments extend these findings by detailing
the effects of experimentally induced injury on taste responses from
anterior tongue taste receptors in sodium-restricted rats. Experiments
focused on functional salt taste responses from the intact chorda
tympani nerve in sodium-restricted rats in which a gustatory nerve was
sectioned that innervates the anterior tongue (chorda tympani), the
posterior tongue (glossopharyngeal), or palatal taste receptors
(greater superficial petrosal) or in which a nongustatory nerve was
sectioned that also has its target in the anterior tongue (trigeminal).
An additional group was studied that received thermal injury to the
anteroventral tongue. Substantial and selective suppression of sodium
salt responses occurred in a graded manner generally related to the
distance from the target field of the injury to anterior tongue taste
buds. The order of effectiveness was: chorda tympani section > trigeminal section > thermal injury = glossopharyngeal
section > greater superficial petrosal section. These results
support the hypothesis that local, diffusible factors liberated from
immune-derived cells as a result of neural and/or epithelial damage are
involved in regulating the transduction pathway responsible for sodium
salt sensation, and that these factors may become evident through
dietary sodium restriction.
Key words:
taste; degeneration; ENaC; chorda tympani nerve; sodium
restriction; immune; epithelia
Copyright © 2002 Society for Neuroscience 0270-6474/02/22198607-07$05.00/0
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