Detection of endogenous dopamine changes in Drosophila melanogaster using fast-scan cyclic voltammetry.
Drosophila melanogaster, the fruit fly, is a commonly used model organism because of its homology to mammals and facile genetic manipulations. However, the size of the nervous system is very small. We report a method to evoke and detect rapid changes in extracellular dopamine in a single nerve cord isolated from a Drosophila larva. Flies were genetically modified to express Channelrhodopsin-2, a blue-light activated cation channel, in only dopaminergic neurons. Extracellular dopamine changes were measured with fast-scan cyclic voltammetry at an implanted carbon-fiber microelectrode. Stimulations of 7 s with blue light result in an average peak dopamine concentration of 810 +/- 60 nM, similar to electrically-stimulated release in mammals. Stimulations repeated at 15 min intervals are stable for 65 min, allowing pharmacological experiments in the same sample. Peak duration is extended after cocaine or nisoxetine, inhibitors of the dopamine transporter (DAT). Release was reduced upon exposure to reserpine, which inhibits vesicular packaging. Chronic administration of NSD-1015, a dopamine synthesis inhibitor, decreased dopamine release and inhibited pupation, showing a link between neurotransmission and physiology. This is the first method to measure endogenous dopamine in an intact larval Drosophila nervous system and will allow studies of genetic and pharmacological manipulations of dopamine release and uptake.
Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, USA.
Trisha L
TL
Vickrey
Barry
B
Condron
B Jill
BJ
Venton
D000818:Animals; D030801:Animals, Genetically Modified; D002490:Central Nervous System / Q000187:drug effects / Q000378:metabolism; D003042:Cocaine / Q000494:pharmacology; D004298:Dopamine / Q000378:metabolism*; D050483:Dopamine Plasma Membrane Transport Proteins / Q000037:antagonists & inhibitors; D004331:Drosophila melanogaster / Q000378:metabolism*; D005473:Fluoxetine / Q000031:analogs & derivatives / Q000494:pharmacology; D006834:Hydrazines / Q000494:pharmacology; D008839:Microelectrodes; D012110:Reserpine / Q000494:pharmacology
D050483:Dopamine Plasma Membrane Transport Proteins; D006834:Hydrazines; D005473:Fluoxetine; C011386:nisoxetine; D012110:Reserpine; C004297:3-hydroxybenzylhydrazine; D003042:Cocaine; D004298:Dopamine