Contents of this page are copyrighted © Hirsh, 2002
Two decapitated Drosophila. Note the blurred wings and hindlegs on the lower fly caused by grooming activity. See Yellman et al (1997).
We have published to the web several quicktime videos illustrating the behaviors shown by decapitated flies as studied in Yellman et al (1997):
Decapitated flies show several behaviors prior to drug treatment, including spontaneous grooming, a provoked grooming response subsequent to stimulation of a sensory bristle, and a strong righting response.
Here are links to quicktime videos showing typical responses of decapitated flies to:
10 mM dopamine,
10 mM dopamine+ 1 mM Hydrazaline
Hydrazaline is an inhibitor of vertebrate monoamine oxidases, and potentiates the amine responses in the decapitated flies.
10 mM Octopamine
10 mM Octopamine+ 1 mM Hydrazaline
1 0 mM quinpirole, a vertebrate D2-like dopamine agonist
2 mM SCH23390, a vertebrate D1-like antagonist
10 mM eticlopride, a vertebrate D2-lik eantagonist
(see McClung et al, 1998), & more recent references.
Living flies are exposed by depositing ca. 75 micrograms of cocaine in ETOH onto a nichrome filament. The ETOH is dried off, then the cocaine is volatilized by heating the filament to ~200C. Flies remain in the exposure vial for ~1 min, then are transferred to a viewing chamber:
Control: flies exposed to +cocaine, the less active isoform of this drug. Flies exhibit normal locomotion & grooming, but no flight due to the limited height of the chamber.
Graded behaviors of flies exposed to increasing doses of free base cocaine:
Behavior 1: An inhibition of locomotion and an increase in grooming behaviors.
Behaviors 2-3: As Behavior 1, but with some meandering locomotion, & extended & pulsing movements of the proboscis.
Behavior 4: Circling behaviors, including forward circling & sideways locomotion.
Behaviors 5-6: Hyperkinetic wing buzzing, termed "seizures", and more strongly affected flies that are akinesic, often with tremor.
Higher magnification view of the circling behaviors.
All movies are copyright protected © Hirsh, 2002. Movies may not be duplicated in any form without written permission from the author.
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