View Program - 63rd Annual Drosophila Research Conference

Aminergic neurons modulate cellular mechanisms involved in almost every human behavior. Norepinephrine in particular has been shown to modulate physiological processes ranging from heart rate to ovulation. Work from our lab and others has shown that the Drosophila equivalent to norepinephrine, octopamine (OA), also has a role in fly ovulation. Processes such as follicle cell rupture in the ovaries, muscle contraction in the oviduct, and sperm storage in the spermathecae have all been shown to be regulated by OA signaling. The specific neurons, receptors, and cellular mechanisms underlying such signaling, however, remain mostly unknown. OA signals to the Drosophila reproductive system from a central cluster of OA neurons in the abdominal ganglion, and both alpha and beta types of OA receptors, which are analogous to the alpha and beta types of mammalian adrenergic receptors, are expressed throughout the reproductive organs. Our lab has developed a set of novel preparations and assays for the optogenetic interrogation of this egg laying circuit. We show that stimulation of the OA cluster innervating the reproductive system produces rhythmic contractions of the lateral oviduct muscle. Our work also suggests that the circuit pathway facilitating this action is indirect, including OA signaling to other intermediate neurons rather than directly to the oviduct muscle, which lacks OA receptor expression. This indirect pathway includes a small group of neurons that express insulin-like peptide 7 (ILP7) and a variety of different neurotransmitters/peptides. OA-driven contractions of the lateral oviducts may therefore incorporate contributions from multiple different types of neurotransmission. By mapping the coexpression of other neurotransmitters and receptors in this circuit, such as glutamate and proctolin, and comparing optogenetically-driven behaviors to those of single-neurotransmitter/peptide perfusions, we aim to define the specific presynaptic and postsynaptic components of this indirect pathway in the OA egg laying circuit. We hypothesize that OA signaling in the egg laying circuit has multiple distinct roles governed by both direct and indirect pathways as well as differences in which OA receptors are expressed in each pathway. This work will help establish a model that can be used to uncover how aminergic neurons coordinate within a single central cluster to regulate multiple different behaviors.

An Octopaminergic Circuit in Egg Laying