Whole-cell patch recording from Drosophila larval neurons

The fruit fly Drosophila melanogaster has been instrumental in expanding our understanding of early aspects of neural development. The use of this model system has greatly added to our knowledge of neural cell-fate determination, axon guidance, and synapse formation. It has also become possible to access and make electrophysiological recordings directly from neurons in situ in an intact central nervous system (CNS), which has facilitated studies of the development and regulation of neuronal signaling. This protocol describes a procedure for revealing larval motor neurons and applying whole-cell patch recording techniques to these cells. The useful lifetime of first-instar larval preparations is ∼30 min, and that of third-instar CNS preparations is up to 1 h. It is therefore recommended that fresh preparations are used and that no breaks are taken during the procedure, although there may be time to pull and polish a patch pipette.