Presentation Title

Loss of the Chorda Tympani Taste Nerve during Development Substantially Decreases its Projections to the Brain

Advisor Information

Suzanne Sollars

Location

UNO Criss Library, Room 231

Presentation Type

Oral Presentation

Start Date

4-3-2016 1:30 PM

End Date

4-3-2016 1:45 PM

Abstract

Four taste nerves transmit sensory information to the nucleus of the solitary tract (NTS) in the brainstem. These nerves’ terminal fields (the area where the nerve contacts brain cells) overlap substantially, creating the potential for competition between nerves. We have previously found that after rats receive a cut of the chorda tympani taste nerve (CTX) at five days of age (P5), two of the other taste nerves change their terminal field organization. However, it is unclear how the CT terminal field is altered after P5 CTX. To address this issue, the CT was labeled to visualize its terminal field 50 days after early nerve transection. At P5, the CT was either transected (CTX) or left intact serve as a control (sham). Fifty days later, adult rats were anesthetized and the CT was loaded with biotinylated dextran amine, a nerve tracer. Following transport of the tracer, brain tissue was collected, sectioned, and processed to allow visualization of the CT terminal field. The terminal field was then traced and volumes were calculated for each group. There was a significant and substantial loss of CT terminal field volume after P5 CTX. After cutting the CT, rats displayed 9% of the total CT volume of sham animals. The largest decrease in volume occurred in the dorsal NTS, the area where other taste nerves expand after P5 CTX. These results suggest that loss of CT terminal fields at an early age create an opportunity for adjacent nerves to expand due to decreased competition.

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Mar 4th, 1:30 PM Mar 4th, 1:45 PM

Loss of the Chorda Tympani Taste Nerve during Development Substantially Decreases its Projections to the Brain

UNO Criss Library, Room 231

Four taste nerves transmit sensory information to the nucleus of the solitary tract (NTS) in the brainstem. These nerves’ terminal fields (the area where the nerve contacts brain cells) overlap substantially, creating the potential for competition between nerves. We have previously found that after rats receive a cut of the chorda tympani taste nerve (CTX) at five days of age (P5), two of the other taste nerves change their terminal field organization. However, it is unclear how the CT terminal field is altered after P5 CTX. To address this issue, the CT was labeled to visualize its terminal field 50 days after early nerve transection. At P5, the CT was either transected (CTX) or left intact serve as a control (sham). Fifty days later, adult rats were anesthetized and the CT was loaded with biotinylated dextran amine, a nerve tracer. Following transport of the tracer, brain tissue was collected, sectioned, and processed to allow visualization of the CT terminal field. The terminal field was then traced and volumes were calculated for each group. There was a significant and substantial loss of CT terminal field volume after P5 CTX. After cutting the CT, rats displayed 9% of the total CT volume of sham animals. The largest decrease in volume occurred in the dorsal NTS, the area where other taste nerves expand after P5 CTX. These results suggest that loss of CT terminal fields at an early age create an opportunity for adjacent nerves to expand due to decreased competition.