title: Modulatory Action by the Serotonergic System: Behavior and Neurophysiology in Drosophila melanogaster.
abstract: Serotonin modulates various physiological processes and behaviors. This study investigates the role of 5-HT in locomotion and feeding behaviors as well as in modulation of sensory-motor circuits. The 5-HT biosynthesis was dysregulated by feeding Drosophila larvae 5-HT, a 5-HT precursor, or an inhibitor of tryptophan hydroxylase during early stages of development. The effects of feeding fluoxetine, a selective serotonin reuptake inhibitor, during early second instars were also examined. 5-HT receptor subtypes were manipulated using RNA interference mediated knockdown and 5-HT receptor insertional mutations. Moreover, synaptic transmission at 5-HT neurons was blocked or enhanced in both larvae and adult flies. The results demonstrate that disruption of components within the 5-HT system significantly impairs locomotion and feeding behaviors in larvae. Acute activation of 5-HT neurons disrupts normal locomotion activity in adult flies. To determine which 5-HT receptor subtype modulates the evoked sensory-motor activity, pharmacological agents were used. In addition, the activity of 5-HT neurons was enhanced by expressing and activating TrpA1 channels or channelrhodopsin-2 while recording the evoked excitatory postsynaptic potentials (EPSPs) in muscle fibers. 5-HT2 receptor activation mediates a modulatory role in a sensory-motor circuit, and the activation of 5-HT neurons can suppress the neural circuit activity, while fluoxetine can significantly decrease the sensory-motor activity.
authors.affiliation: Department of Biology, University of Kentucky, Lexington, KY 40506, USA; Department of Biology, College of Science, Salahaddin University-Erbil, Erbil, Iraq.
authors.forename: Zana R
authors.initials: ZR
authors.lastname: Majeed
authors.affiliation: Department of Biology, University of Kentucky, Lexington, KY 40506, USA.
authors.forename: Esraa
authors.initials: E
authors.lastname: Abdeljaber
authors.affiliation: Department of Biology, University of Kentucky, Lexington, KY 40506, USA; Paul Laurence Dunbar High School, Lexington, KY 40513, USA.
authors.forename: Robin
authors.initials: R
authors.lastname: Soveland
authors.affiliation: Department of Biology, University of Kentucky, Lexington, KY 40506, USA.
authors.forename: Kristin
authors.initials: K
authors.lastname: Cornwell
authors.affiliation: Department of Biology, University of Kentucky, Lexington, KY 40506, USA.
authors.forename: Aubrey
authors.initials: A
authors.lastname: Bankemper
authors.affiliation: Veterinärmedizinische Fakultät, Universität Leipzig, 04103 Leipzig, Germany.
authors.forename: Felicitas
authors.initials: F
authors.lastname: Koch
authors.affiliation: Department of Biology, University of Kentucky, Lexington, KY 40506, USA.
authors.forename: Robin L
authors.initials: RL
authors.lastname: Cooper
mesh_terms: D006916:5-Hydroxytryptophan / Q000008:administration & dosage; D000818:Animals; D001921:Brain / Q000502:physiology*; D029721:Drosophila Proteins / Q000378:metabolism; D004331:Drosophila melanogaster; D004791:Enzyme Inhibitors / Q000008:administration & dosage; D019706:Excitatory Postsynaptic Potentials; D005247:Feeding Behavior / Q000187:drug effects / Q000502:physiology*; D010134:Fenclonine / Q000008:administration & dosage; D008124:Locomotion / Q000187:drug effects; D021122:Protein Subunits / Q000378:metabolism; D011985:Receptors, Serotonin / Q000502:physiology; D011984:Sensory Receptor Cells / Q000502:physiology; D059326:Serotonergic Neurons / Q000502:physiology*; D012701:Serotonin / Q000008:administration & dosage / Q000502:physiology*; D014365:Tryptophan Hydroxylase / Q000378:metabolism
chemical_list: D029721:Drosophila Proteins; D004791:Enzyme Inhibitors; D021122:Protein Subunits; D011985:Receptors, Serotonin; D012701:Serotonin; D006916:5-Hydroxytryptophan; D014365:Tryptophan Hydroxylase; D010134:Fenclonine