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dc.contributor.advisor Tracey, William Daniel en_US
dc.contributor.author Hwang, Richard Yi-Jen en_US
dc.date.accessioned 2009-08-27T18:39:48Z
dc.date.available 2011-08-27T04:30:07Z
dc.date.issued 2009 en_US
dc.identifier.uri http://hdl.handle.net/10161/1348
dc.description Dissertation en_US
dc.description.abstract <p>Pain is defined by the international association of pain as an "unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage". Most people have experienced one form of pain or another and although such experiences can be unsavory, pain serves the basic need for the detection of dangerous stimuli that can cause bodily harm. Because pain serves such an essential need, it is important to understand how the nervous system processes and encodes noxious or potentially tissue damaging stimuli. This neural processing is called nociception. </p><p>In this study, I use Drosophila larvae as a genetic model organism to study nociception. In response to noxious thermal and mechanical stimuli, Drosophila larvae perform a nociceptive defensive behavior (termed nocifensive) where larvae rotate in a corkscrew like fashion along the long axis causing them to move in a lateral direction. Using this behavior and genetic tools which can manipulate neuronal output, we have identified the sensory neurons which serve as larval nociceptors as class IV multidendritic sensory neurons. Further characterization of these larval nociceptors, has also shown that they are both cholinergic and peptidergic.</p><p>After the identifying the larval nociceptors, I next identified several molecular components which are required for larval mechanical nociception. I have found that the degenerin epithelial sodium channel (DEG/ENaC) called pickpocket is required for larval mechanical nociception by using genetic mutants and RNAi knockdwon. In addition, after performing a screen using RNAi to knockdown ion channel transcripts in larval nociceptors, I have identified two other DEG/ENaC channels which are required for larval mechanical nociception. DEG/ENaCs are particularly interesting because they have been identified as candidate mechanotransducers in C. elegans for the gentle touch behavior. I propose that DEG/ENaCs may serve as candidate mechanotransducers in larval mechanical nociception because they are not generally required for neuronal excitability. However, future research will be required to establish their true role in mechanical nociceptive signaling.</p><p>In addition to DEG/ENaCs, transient receptor potential (TRP) channels also play a role in nociception. painless, a channel that was first identified in a thermal nociception screen on Drosophila larvae, is required for both thermal and mechanical nociception. The last section shows that multiple isoforms of painless exist and that these different isoforms may play different roles in thermal and mechanical nociception. </p><p>Taken together, these results have begun to establish Drosophila larva as a model for studying nociception. I have identified the sensory neurons used as larval nociceptors and shown that DEG/ENaC channels play an important role in larval mechanical nociception.</p> en_US
dc.format.extent 1925153 bytes
dc.format.mimetype application/pdf
dc.language.iso en_US
dc.subject Biology, Neuroscience en_US
dc.subject drosophila en_US
dc.subject ion channel en_US
dc.subject larva en_US
dc.subject mechanosensation en_US
dc.subject nociception en_US
dc.subject pain en_US
dc.title Circuitry and Genes of Larval Nociception in Drosophila Melanogaster en_US
dc.type Dissertation en_US
dc.department Neurobiology en_US
duke.embargo.months 24 en_US

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