Astroglial exocytosis: a note of caution from the perspective of a single-vesicle spectrosopist

old_uid1646
titleAstroglial exocytosis: a note of caution from the perspective of a single-vesicle spectrosopist
start_date2006/10/23
schedule11h30
onlineno
detailsInvité par JP Mothet CRI /INB
summaryGlial cells have recently been implicated in bidirectional signaling from and to neurons at central synapses. Equiped with a plethora of neurotransmitter receptors and releasing neuroactive substances that classically have been considered as transmitters and neuromodulators of only neuronal origin, astroglia are increasingly being placed in the concept of a 'tripartite synapse' that -in addition to the classically recognized pre- and postsynaptic compartments-- involves glial processes that actively stimulate neuronal activity. Among the different pathways suggested for a regulated 'gliotransmitter' release, our lab has focused on the Ca(2+)-regulated vesicular (exocytotic) release of neuroactive substances by cortical astroglia. Using a combination of molecular genetics, single-vesicle imaging and spectrocopic techniques, we tagged, tracked and classifed astroglial vesicular compartments and their response to various challenges. Our data contradicts earlier observations of a large abundance of glutamatergic near-membrane vesicles in cultured astroglia and calls for a reconsideration of co-localization data based on EGFP expression and Acridine Orange labelling. Instead, we emphasize the importance of a highly dynamic population of secretory lysosomes.
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