Molecular and genetic approaches to neurotransmitter and neuromodulator systems in drosophila

Drosophila melanogaster provides one of the most powerful experimental systems for studying genetic and molecular aspects of nervous system physiology and development. This chapter summarizes studies of compounds that are postulated to mediate or modulate neurotransmission in Drosophila with an emphasis on the genetic approaches used to study them. The premise is that the classical and molecular genetics have the potential to enhance biochemical, immunochemical, and physiological studies of neurotransmitter and neuromodulator function. This chapter covers four major classes of putative neurotransmitters or neuromodulators: (1) acetylcholine (Ach), (2) biogenic amines, (3) amino acids, and (4) neuropeptides. In no instance is there incontrovertible evidence for a role in neurotransmission, although the case for glutamate at the neuromuscular junction is quite strong. For acetylcholine, there is a great deal of circumstantial evidence that is often derived from genetic analyses. In other cases, postulated roles are based solely on analogies with work in other species.