GLIAL CELL MODULATION OF MOTORNEURON ACTIVITY AS REVEALED BY BEHAVIORAL ASSAYS IN DROSOPHILA LARVAE

picture of Cathy Tran presenting his/her poster: GLIAL CELL MODULATION OF MOTORNEURON ACTIVITY AS REVEALED BY BEHAVIORAL ASSAYS IN DROSOPHILA LARVAE

Cathy Tran , Sarah MacNamee, Lynne Oland

GLIAL CELL MODULATION OF MOTORNEURON ACTIVITY AS REVEALED BY BEHAVIORAL ASSAYS IN DROSOPHILA LARVAE

The field of neuroscience has historically emphasized the synaptic connections between neurons, while interactions between neurons and glial cells have largely been overlooked, despite increasing evidence of the importance of glial cells in development and in mature functioning of the nervous system.  In vertebrates, the number of glial cells is essentially the same as the number of neurons. Glia also have well-established roles in the pathology of many nervous system diseases, including neurodegenerative conditions like Alzheimer’s Disease, ALS, and Parkinson’s Disease, as well as brain tumors.  Full understanding of the physiology and pathology of the nervous system thus requires a picture that takes into account both glia and neurons, therefore creating a necessity to learn more about the roles of glial cells. We study glial-neuron interactions using a genetic fruit fly system (Drosophila).  Here, the motor neurons in the ventral nerve cord have dendrites that are intermingled among the processes of astrocyte-like neuropil glia; their axons terminate on muscles. The proximity of the two cells and their process overlap suggests that the signals from one cell class are received by the other and vice versa. Our experimental design uses motor neurons to identify changes in glial cell signaling mechanisms that affect neurons. We use genetic engineering to disrupt potential signaling mechanisms specifically in the glial cells. We are currently performing behavioral screens using locomotion assays, such as peristalsis counting, righting, and tail-touch tests. Because motor neurons send signals directly to the muscles, we can determine the impact of the glial disruptions on neurons by observing the locomotion behavior. Our preliminary data show that there is a significant decrease in peristaltic contractions when we disrupt the transporter for the neurotransmitter GABA, compared to control animals. Glial mutants that show strong behavioral effects will become subjects for detailed electrophysiological and morphological analysis.

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