Senior Honors Projects, 2010-current

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Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Date of Graduation

Spring 2019

Document Type

Thesis

Degree Name

Bachelor of Science (BS)

Department

Department of Biology

Advisor(s)

Susan R. Halsell

Abstract

Nociception is the perception of and response to harmful stimuli. Nociception is essential for minimizing tissue damage, but aberrant nociceptive pathways can result in chronic pain. Chronic pain in the U.S. is commonly managed with wide-acting opioids, and precisely defining the components of nociceptive pathways could uncover novel targets for pain therapies. I hypothesize that the vitally quick process of nociception would utilize electrical synapses because they transmit signals between neurons more quickly than chemical synapses do. This study, therefore, aims to uncover the potential role of the eight Drosophila melanogaster gap junction proteins, the Innexins, in cold nociception. Wild type Drosophila larvae exhibit a characteristic full-body contraction, or cringe, in response to noxious cold. The expression level of individual Innexins was knocked down in the peripheral dendritic arborization (da) neurons that mediate cold nociception via the Drosophila GAL4/UAS RNAi system. Knocked-down larvae were subjected to a cold behavioral assay, and their behavior was videotaped and analyzed to quantify the “percent cringe” value in order to identify the number of “non-cringers” for statistical analysis. By comparing the proportion of non-cringers between the knock-down larvae and the wild type, the involvement of the knocked-down Innexin in the cold nociceptive pathway was inferred. A Class III da neuron-specific tetanus toxin control was used. All eight Drosophila Innexins were tested with at least one RNAi construct expressed in class III da neurons. Thirteen of the fourteen total RNAi constructs resulted in significantly fewer cringers (Fischer’s Two-Tailed Exact T-Test, p<0.05). Future studies are proposed to characterize the Innexins’ role in cold nociception further.

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