title: In vivo bioluminescence imaging of Ca signalling in the brain of Drosophila.
abstract: Many different cells' signalling pathways are universally regulated by Ca(2+) concentration [Ca(2+)] rises that have highly variable amplitudes and kinetic properties. Optical imaging can provide the means to characterise both the temporal and spatial aspects of Ca(2+) signals involved in neurophysiological functions. New methods for in vivo imaging of Ca(2+) signalling in the brain of Drosophila are required for probing the different dynamic aspects of this system. In studies here, whole brain Ca(2+) imaging was performed on transgenic flies with targeted expression of the bioluminescent Ca(2+) reporter GFP-aequorin (GA) in different neural structures. A photon counting based technique was used to undertake continuous recordings of cytosolic [Ca(2+)] over hours. Time integrals for reconstructing images and analysis of the data were selected offline according to the signal intensity. This approach allowed a unique Ca(2+) response associated with cholinergic transmission to be identified by whole brain imaging of specific neural structures. Notably, [Ca(2+)] transients in the Mushroom Bodies (MBs) following nicotine stimulation were accompanied by a delayed secondary [Ca(2+)] rise (up to 15 min. later) in the MB lobes. The delayed response was sensitive to thapsigargin, suggesting a role for intra-cellular Ca(2+) stores. Moreover, it was reduced in dunce mutant flies, which are impaired in learning and memory. Bioluminescence imaging is therefore useful for studying Ca(2+) signalling pathways and for functional mapping of neurophysiological processes in the fly brain.
authors.affiliation: Equipe: Bases Neurales des Comportements chez la Drosophile, Laboratoire de Neurobiologie Cellulaire et Moléculaire (NBCM), Centre National de la Recherche Scientifique (CNRS), Unité UPR-9040, Gif-sur-Yvette, France. jean-rene.martin@inaf.cnrs-gif.fr
authors.forename: Jean-René
authors.initials: JR
authors.lastname: Martin
authors.forename: Kelly L
authors.initials: KL
authors.lastname: Rogers
authors.forename: Carine
authors.initials: C
authors.lastname: Chagneau
authors.forename: Philippe
authors.initials: P
authors.lastname: Brûlet
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001921:Brain / Q000033:anatomy & histology / Q000502:physiology*; D002118:Calcium / Q000502:physiology*; D004330:Drosophila / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects; D005819:Genetic Markers; D049452:Green Fluorescent Proteins / Q000235:genetics; D008027:Light; D049449:Luminescence; D008164:Luminescent Proteins / Q000235:genetics / Q000502:physiology; D015398:Signal Transduction
chemical_list: D005819:Genetic Markers; D008164:Luminescent Proteins; D049452:Green Fluorescent Proteins; D002118:Calcium