Effect of Ethanol Withdrawal on Dunce Gene Expression and Learning in Drosophila melanogaster

Abstract

The purpose of this experiment was to test whether ethanol withdrawal inhibits short-term memory in Drosophila melanogaster. Prior research has shown that Drosophila who have experienced withdrawal from ethanol display an inability to associate a positive odorant with the negative response of a heat shock. For this experiment, it was hypothesized that these effects are due to a malfunction in cAMP Phosphodiesterase formation, which causes a buildup of cAMP and impairs intracellular neuronal cell signaling. This hypothesis was tested by measuring short-term memory formation and expression of the Dunce gene in Drosophila that experienced ethanol withdrawal. The dunce gene was chosen because its encoded protein plays an essential role in intracellular neuronal cell signaling. To test the hypothesis, experimental cultures of Drosophila were maintained in a nutrient rich media supplemented with 5% ethanol. The production of short-term memory was monitored using a non-reciprocal conditioning assay. This protocol was followed over the course of six, 24 and 48 hours following the withdrawal of ethanol. After 24 hours, RNA was extracted and Reverse Transcription – quantitative Polymerase Chain Reactions (RT-qPCRs) were performed to determine expression of the Dunce gene. It was predicted that ethanol withdrawal would inhibit short-term memory formation in Drosophila and that expression of the Dunce gene would be reduced.