PHYSIOLOGY AND BIOCHEMISTRY
Drosophila testing used to determine role of genetic variation in dopamine drug
treatments. EMILY HOLSOPPLE1, EMILY RAYENS2, JORDAN RICE3, JOSH
TITLOW 1 AND ROBIN L. COOPER1 .
1University of Kentucky, Lexington KY 40508, USA; Department of Biology. 2Wittenberg
University, OH; 3Transylvania University, Lexington, KY 40508, USA
Dopamine (DA) is an ancient neurotransmitter known to exist in phyla ranging from
arthropods to humans. DA has been proven to modulate sensory-motor circuits,
affecting organisms’ physical reactions to stimuli. To examine this modulatory role we
tested genetically different strands of Drosophila using an assay on their larvae. The
results from this assay revealed pertinent information concerning the roles of different
genes and mutations in neural signaling in DA pathways. In this assay a control (RAL
820) and mutant (RAL 730) were used and tested with the HAT method. This method is
named after the regions where the stimulus is administered, H being head, A being
abdomen and T for tail. The larvae were poked in each of these regions and their
different responses were recorded and quantified. Responses were then examined after
treating the larvae with various DA concentrations for one hour. The data collected
showed that DA receptor expression levels in the RAL 820 line of flies were almost
twice as high as the 730 line. Our prediction was that this would result in them being
more sensitive to exogenous DA, which we found to be true. After being treated with the
exogenous DA, the RAL 820 reactions showed a much greater increase in sensitivity
than the 730 line. The biggest increase was in the tail region of the RAL 820 where the
sensitivity more than doubled. The change in sensitivity in the lines when exposed to
exogenous DA showed proof of a genetic link in DA expression.