Taste activity in the parabrachial region in adult rats following neonatal chorda tympani transection

Authors

Louis J. Martin, University of Nebraska at Omaha
Joseph M. Breza, Eastern Michigan University
Suzanne I. Sollars, University of Nebraska at OmahaFollow

Author ORCID Identifier

Louis J. Martin: https://orcid.org/0000-0002-5168-8904

Suzanne I. Sollars:

Document Type

Article

Publication Date

6-1-2021

Publication Title

Journal of Neurophysiology

Volume

125

Issue

6

First Page

2178

Last Page

2190

Abstract

The chorda tympani is a gustatory nerve that fails to regenerate if sectioned in rats 10 days of age or younger. This early denervation causes an abnormally high preference for NH₄Cl in adult rats, but the impact of neonatal chorda tympani transection on the development of the gustatory hindbrain is unclear. Here, we tested the effect of neonatal chorda tympani transection (CTX) on gustatory responses in the parabrachial nucleus (PbN). We recorded in vivo extracellular spikes in single PbN units of urethane-anesthetized adult rats following CTX at P5 (chronic CTX group) or immediately prior to recording (acute CTX group). Thus, all sampled PbN neurons received indirect input from taste nerves other than the CT. Compared to acute CTX rats, chronic CTX animals had significantly higher responses to stimulation with 0.1 and 0.5 M NH₄Cl, 0.1 NaCl, and 0.01 M citric acid. Activity to 0.5 M sucrose and 0.01 M quinine stimulation was not significantly different between groups. Neurons from chronic CTX animals also had larger interstimulus correlations and significantly higher entropy, suggesting that neurons in this group were more likely to be activated by stimulation with multiple tastants. Although neural responses were higher in the PbN of chronic CTX rats compared to acute-sectioned controls, taste-evoked activity was much lower than observed in previous reports, suggesting permanent deficits in taste signaling. These findings demonstrate that the developing gustatory hindbrain exhibits high functional plasticity following early nerve injury.

Comments

Copyright (2021) the American Physiological Society

This is an Accepted Manuscript of an article published in The Journal of Neurophysiology on June 1, 2021, available online: https://doi.org/10.1152/jn.00552.2020

Recommended Citation

Martin, Louis J.; Breza, Joseph M.; and Sollars, Suzanne I., "Taste activity in the parabrachial region in adult rats following neonatal chorda tympani transection" (2021). Psychology Faculty Publications. 239.
https://digitalcommons.unomaha.edu/psychfacpub/239