title: Dopaminergic modulation of arousal in Drosophila.
abstract: BACKGROUND
  Arousal levels in the brain set thresholds for behavior, from simple to complex. The mechanistic underpinnings of the various phenomena comprising arousal, however, are still poorly understood. Drosophila behaviors have been studied that span different levels of arousal, from sleep to visual perception to psychostimulant responses.
  
  
  RESULTS
  We have investigated neurobiological mechanisms of arousal in the Drosophila brain by a combined behavioral, genetic, pharmacological, and electrophysiological approach. Administration of methamphetamine (METH) suppresses sleep and promotes active wakefulness, whereas an inhibitor of dopamine synthesis promotes sleep. METH affects courtship behavior by increasing sexual arousal while decreasing successful sexual performance. Electrophysiological recordings from the medial protocerebrum of wild-type flies showed that METH ingestion has rapid and detrimental effects on a brain response associated with perception of visual stimuli. Recordings in genetically manipulated animals show that dopaminergic transmission is required for these responses and that visual-processing deficits caused by attenuated dopaminergic transmission can be rescued by METH.
  
  
  CONCLUSIONS
  We show that changes in dopamine levels differentially affect arousal for behaviors of varying complexity. Complex behaviors, such as visual perception, degenerate when dopamine levels are either too high or too low, in accordance with the inverted-U hypothesis of dopamine action in the mammalian brain. Simpler behaviors, such as sleep and locomotion, show graded responses that follow changes in dopamine level.
authors: The Neuroscience Institute, San Diego, California 92121, USA.
authors: Rozi
authors: R
authors: Andretic
authors: Bruno
authors: B
authors: van Swinderen
authors: Ralph J
authors: RJ
authors: Greenspan
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001143:Arousal / Q000187:drug effects*; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D004296:Dopa Decarboxylase / Q000378:metabolism; D004298:Dopamine / Q000096:biosynthesis* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004330:Drosophila / Q000235:genetics / Q000378:metabolism*; D029721:Drosophila Proteins / Q000235:genetics; D034281:Dynamins / Q000235:genetics; D004594:Electrophysiology; D008694:Methamphetamine / Q000494:pharmacology*; D009154:Mutation / Q000235:genetics; D012726:Sexual Behavior, Animal / Q000187:drug effects*; D012890:Sleep / Q000187:drug effects; D014796:Visual Perception / Q000502:physiology
chemical_list: D029721:Drosophila Proteins; D008694:Methamphetamine; D034281:Dynamins; C439628:shi protein, Drosophila; D004296:Dopa Decarboxylase; D004298:Dopamine