title: Neuromuscular control of a single twitch muscle in wild type and mutant Drosophila, measured with an ergometer.
abstract: How do deficits in neuronal growth, aging or synaptic function affect the final, mechanical output of a single muscle twitch? We address this in vivo (indeed in situ) with a novel ergometer that records the output of a large specialised muscle, the Drosophila jump muscle. Here, we describe in detail the ergometer, its construction and use. We evaluated the ergometer by showing that adult fly jump muscle output varies little between 3 h and 7 days; but newly eclosed flies produce only 65%. In a mutant with little octopamine (Tbetah), jump muscle performance is reduced by 28%. The initial responses of synaptic growth mutants (highwire and spinster) do not differ from wild type, as expected on the homeostatic hypothesis. However, responses in highwire mutations gradually decline following repeated stimuli, suggesting physiological as well as anatomical abnormalities. We conclude that the assay is robust, sensitive and reliable with a good throughput.
authors.affiliation: Department of Biology, University of York, PO Box 373, York, UK.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Harvey
authors.forename: Holly
authors.initials: H
authors.lastname: Brunger
authors.forename: C Adam
authors.initials: CA
authors.lastname: Middleton
authors.forename: Julia A
authors.initials: JA
authors.lastname: Hill
authors.forename: Maria
authors.initials: M
authors.lastname: Sevdali
authors.forename: Sean T
authors.initials: ST
authors.lastname: Sweeney
authors.forename: John C
authors.initials: JC
authors.lastname: Sparrow
authors.forename: Christopher J H
authors.initials: CJ
authors.lastname: Elliott
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D004330:Drosophila / Q000235:genetics / Q000502:physiology*; D016552:Ergometry / Q000295:instrumentation / Q000379:methods; D009132:Muscles / Q000502:physiology*; D009154:Mutation; D009469:Neuromuscular Junction / Q000502:physiology*; D009655:Octopamine / Q000235:genetics
chemical_list: D009655:Octopamine