Neurocircuit Assays for Seizures in Epilepsy Mutants of Drosophila
Summary
Using high frequency electrical stimulation, seizure-like activity can be induced in Drosophila. This activity is easily recorded from the giant fiber system.
Abstract
Drosophila melanogaster is a useful tool for studying seizure like activity. A variety of mutants in which seizures can be induced through either physical shock or electrical stimulation is available for study of various aspects of seizure activity and behavior. All flies, including wild-type, will undergo seizure-like activity if stimulated at a high enough voltage. Seizure like activity is an all-or-nothing response and each genotype has a specific seizure threshold. The seizure threshold of a specific genotype of fly can be altered either by treatment with a drug or by genetic suppression or enhancement. The threshold is easily measured by electrophysiology. Seizure-like activity can be induced via high frequency electrical stimulation delivered directly to the brain and recorded through the dorsal longitudinal muscles (DLMs) in the thorax. The DLMs are innervated by part of the giant fiber system. Starting with low voltage, high frequency stimulation, and subsequently raising the voltage in small increments, the seizure threshold for a single fly can be measured.
Protocol
Specimen Preparation: The night before the experiment, male flies of the desired genotype are anesthetized and placed in a vial with a soft nylon plug. A cotton ball would also work. Following anesthetization, the seizure threshold is altered, so the flies are best left for at least 6 hours, though over night is ideal. On the day of the experiment, the flies are mounted one at a time to glass slides with a layer of dental wax on one side. A…
Discussion
This video has demonstrated the basic steps in determining the seizure threshold of an individual Drosophila fly. Instead of using the digital oscilloscope, a computerized digitizer may also be used. This technique is useful for determine the effects of a drug or genetic alteration on the seizure threshold of a fly.
Acknowledgements
This work was supported by an NIH research grant, an Epilepsy Foundation grant and a McKnight Foundation grant to M.T. Experiments on Drosophila fruit flies were performed in accordance with the guidelines and regulations set forth by the UC Berkeley Animal Use Committee.
Materials
| Material Name | Tipo | Company | Catalogue Number | Comment |
|---|---|---|---|---|
| Digital oscilloscope | Hitachi | VC-6523 | ||
| Stimulator | Cornerstone | S-900 | ||
| Preamplifier | World Precision Instruments | Electro 705 | ||
| Micromanipulators | Narishige | various |
Riferimenti
- Kuebler, D., Tanouye, M. A. Modifications of seizure susceptibility in Drosophila. J Neurophysiol. 83, 998-1009 (2000).
- Kuebler, D., Zhang, H., Ren, X., Tanouye, M. A. Genetic suppression of seizure susceptibility in Drosophila. J Neurophysiol. 86, 1211-1225 (2001).
- Song, J., Tanouye, M. A. Seizure suppression by shakB2, a gap junction mutation in Drosophila. J Neurophysiol. 95, 627-635 (2006).
Tags
Neurocircuit AssaysSeizuresEpilepsy MutantsDrosophila MelanogasterSeizure-like ActivityPhysical ShockElectrical StimulationGenotypeSeizure ThresholdDrug TreatmentGenetic SuppressionGenetic EnhancementElectrophysiologyHigh Frequency Electrical StimulationDorsal Longitudinal Muscles (DLMs)Giant Fiber System
Citazione di questo articolo
Howlett, I. C., Tanouye, M. A. Neurocircuit Assays for Seizures in Epilepsy Mutants of Drosophila. J. Vis. Exp. (26), e1121, doi:10.3791/1121 (2009).