Investigating the Neural Mechanisms Mediating Cold Nociception in Drosophila

Understanding the body’s response to nociception is valuable and crucial to survival. Drosophila melanogaster is a model system for understanding cold nociception. It is well known that Class II (CII) and Class III (CIII) multidendritic (md) neurons of Drosophila larvae are essential in cold nociception; however, there is little to no information on other groups of neurons that are involved. To further explore this gap in the literature, this proposal will employ activation and inactivation techniques on two different populations of neurons in Drosophila larvae marked by a specific GAL4 driver, either GMR 41F12 or GMR 31D03, in efforts to reveal any additional neural circuitry potentially involved in cold nociceptive behavior (i.e., bilateral contracting, slowing of movement, etc.). A cold-plate assay using toxin-induced inactivation of these specific neural populations is implemented to examine whether they are necessary for producing the typical nociceptive behaviors exhibited in response to cold stimulation, and optogenetic activation of these populations in the absence of any stimuli is separately performed to determine whether they are sufficient to produce the expected nociceptive behaviors. Examining whether these neuronal populations are necessary and/or sufficient for cold nociceptive behavior will provide us with additional information about the neural circuitry that underlies cold nociception on top of the already known influence of CII and CIII md neurons. Analyses provided some evidence for GMR 41F12 being a necessary component of the cold circuit, and evidence for GMR 31D03 potentially playing more of a modulatory role in nociceptive behavior in response to noxious cold.