Single neuron activity in the Drosophila larval CNS detected with calcium indicators.
Although the Drosophila larva has been extensively used for genetic studies of synaptic transmission and locomotion, neurophysiological studies have lagged because it is difficult to investigate circuitry and synaptic function in the larval central nervous system (CNS). Here we introduce an optical technique to monitor neuronal activity in the intact Drosophila larval CNS. We loaded neurons retrogradely through cut axons with dextran-conjugated calcium indicators. Fluorescence responses to changes in the concentration of intracellular calcium are sufficiently fast and large to monitor electrical activity in single neurons. Responses to action potentials were detected in motor neuron cell bodies, axons, neurites, dendrites and sensory neuron afferents identified by genetically targeted green fluorescent protein expression. Our findings provide an experimental procedure for testing synaptic function and connectivity within the intact larval CNS.
Macleod
G T
GT
Department of Physiology, University of Toronto, Medical Sciences Building Rm. 3308, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8. greg.macleod@mail.utexas.edu
Suster
M L
ML
Charlton
M P
MP
Atwood
H L
HL
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002490:Central Nervous System / Q000033:anatomy & histology / Q000502:physiology*; D003712:Dendrites / Q000378:metabolism; D004307:Dose-Response Relationship, Radiation; D004330:Drosophila; D004558:Electric Stimulation; D005456:Fluorescent Dyes / Q000378:metabolism; D049452:Green Fluorescent Proteins; D007202:Indicators and Reagents / Q000378:metabolism; D007814:Larva / Q000502:physiology*; D008164:Luminescent Proteins / Q000378:metabolism; D018613:Microscopy, Confocal / Q000295:instrumentation / Q000379:methods*; D009434:Neural Pathways / Q000378:metabolism; D016501:Neurites / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D013569:Synapses; D013997:Time Factors
D005456:Fluorescent Dyes; D007202:Indicators and Reagents; D008164:Luminescent Proteins; D049452:Green Fluorescent Proteins; D002118:Calcium