Taste and Touch: The Electrophysiological Consequence of Lingual Nerve Injury on the Chorda Tympani Nerve
Presenter Type
UNO Undergraduate Student
Major/Field of Study
Neuroscience
Advisor Information
Suzanne I. Sollars, PhD.
Location
MBSC Ballroom Poster # 607 - U
Presentation Type
Poster
Start Date
24-3-2023 1:00 PM
End Date
24-3-2023 2:15 PM
Abstract
The tongue serves as a host to two distinct sensory systems: taste and touch. Across the surface of the tongue, mushroom shaped structures called papillae are sensitive to texture, temperature, and noxious chemicals like capsaicin. Located within the papillae, taste buds respond to chemicals associated with various tastes. Each structure relays information to the central nervous system via peripheral nerves, with the chorda tympani nerve (CT) connecting to the taste buds and the lingual nerve (LN) connecting to the papillae. Previous studies indicate that the injury of either nerve at an early developmental period leads to a long-lasting deterioration of both papillae and taste buds. The current study seeks to determine whether LN injury (LX) in young Sprague-Dawley rats leads to cross-sensory changes in CT responses across development. The LN was cut at 10 days of age in such a way that the CT remained intact. Another group of animals constituted the control group with some undergoing a SHAM surgery (wherein the LN was observed but not cut), and some undergoing no surgical procedure. Whole nerve electrophysiology was used at adolescent (14 - 21 days post LX) and adult (>50 days post LX) developmental periods to assess CT responses. Different concentrations of taste solutions associated with the basic tastes of salty (NaCl, sodium acetate), sweet (sucrose), sour (citric acid), and bitter (quinine) were used to elicit CT responses, which were recorded relative to a standard solution (ammonium chloride). In the taste bud, there are two kinds of sodium channels that initiate the CT response. By using the antagonist, amiloride, some sodium channels can be blocked, leaving amiloride-insensitive channels available. Assessing the CT response following amiloride indicates whether LX changes the proportion and distribution of these channels. Preliminary data indicate that LX leads to an increase in CT response to sodium acetate at high concentrations (0.5M and 1.0 M), regardless of the developmental period. The CT response to NaCl and sodium acetate is suppressed by amiloride. This suppression appears to occur to a greater degree at the mid-range concentrations (0.1M and 0.25M) of sodium acetate at the adult developmental period following LX. Continuing research will elucidate the effects of amiloride and identify whether changes occur at earlier developmental stages.
Scheduling
9:15-10:30 a.m., 10:45 a.m.-Noon, 1-2:15 p.m., 2:30 -3:45 p.m.
Taste and Touch: The Electrophysiological Consequence of Lingual Nerve Injury on the Chorda Tympani Nerve
MBSC Ballroom Poster # 607 - U
The tongue serves as a host to two distinct sensory systems: taste and touch. Across the surface of the tongue, mushroom shaped structures called papillae are sensitive to texture, temperature, and noxious chemicals like capsaicin. Located within the papillae, taste buds respond to chemicals associated with various tastes. Each structure relays information to the central nervous system via peripheral nerves, with the chorda tympani nerve (CT) connecting to the taste buds and the lingual nerve (LN) connecting to the papillae. Previous studies indicate that the injury of either nerve at an early developmental period leads to a long-lasting deterioration of both papillae and taste buds. The current study seeks to determine whether LN injury (LX) in young Sprague-Dawley rats leads to cross-sensory changes in CT responses across development. The LN was cut at 10 days of age in such a way that the CT remained intact. Another group of animals constituted the control group with some undergoing a SHAM surgery (wherein the LN was observed but not cut), and some undergoing no surgical procedure. Whole nerve electrophysiology was used at adolescent (14 - 21 days post LX) and adult (>50 days post LX) developmental periods to assess CT responses. Different concentrations of taste solutions associated with the basic tastes of salty (NaCl, sodium acetate), sweet (sucrose), sour (citric acid), and bitter (quinine) were used to elicit CT responses, which were recorded relative to a standard solution (ammonium chloride). In the taste bud, there are two kinds of sodium channels that initiate the CT response. By using the antagonist, amiloride, some sodium channels can be blocked, leaving amiloride-insensitive channels available. Assessing the CT response following amiloride indicates whether LX changes the proportion and distribution of these channels. Preliminary data indicate that LX leads to an increase in CT response to sodium acetate at high concentrations (0.5M and 1.0 M), regardless of the developmental period. The CT response to NaCl and sodium acetate is suppressed by amiloride. This suppression appears to occur to a greater degree at the mid-range concentrations (0.1M and 0.25M) of sodium acetate at the adult developmental period following LX. Continuing research will elucidate the effects of amiloride and identify whether changes occur at earlier developmental stages.