Fast subplasma membrane Ca2+ transients control exo-endocytosis of synaptic-like microvesicles in astrocytes

Autor: Haiyan Li, Julie Marchaland, Corrado Calì, Robert H. Edwards, Susan M. Voglmaier, Paola Bezzi, Romano Regazzi
Jazyk: angličtina
Rok vydání: 2008
Předmět:
astrocytes
secretion
imaging
Green Fluorescent Proteins
Astrocytes
Calcium
Endocytosis
Exocytosis
Glutamate release
Imaging
Biology
Transfection
Article
Methoxyhydroxyphenylglycol
Cell membrane
Glutamatergic
Glial Fibrillary Acidic Protein
medicine
Animals
Calcium Signaling
Cells
Cultured
Calcium signaling
Analysis of Variance
Dose-Response Relationship
Drug
Glial fibrillary acidic protein
General Neuroscience
Endoplasmic reticulum
Cell Membrane
Analysis of Variance Animals Animals
Newborn Astrocytes/*cytology Calcium/*metabolism Calcium Signaling/drug effects/physiology Cell Membrane/drug effects/*physiology Cells
Cultured Dose-Response Relationship
Drug Endocytosis/drug effects/*physiology Glial Fibrillary Acidic Protein/metabolism Green Fluorescent Proteins/metabolism Kinetics Methoxyhydroxyphenylglycol/analogs & derivatives/pharmacology Rats Transfection/methods Vesicular Glutamate Transport Protein 1/genetics/metabolism
Microvesicles
Rats
Cell biology
Kinetics
medicine.anatomical_structure
Animals
Newborn
Vesicular Glutamate Transport Protein 1
biology.protein
Zdroj: Journal of Neuroscience, vol. 28, no. 37, pp. 9122-9132
Popis: Astrocytes are the most abundant glial cell type in the brain. Although not apposite for long-range rapid electrical communication, astrocytes share with neurons the capacity of chemical signaling via Ca2+-dependent transmitter exocytosis. Despite this recent finding, little is known about the specific properties of regulated secretion and vesicle recycling in astrocytes. Important differences may exist with the neuronal exocytosis, starting from the fact that stimulus-secretion coupling in astrocytes is voltage independent, mediated by G-protein-coupled receptors and the release of Ca2+from internal stores. Elucidating the spatiotemporal properties of astrocytic exo-endocytosis is, therefore, of primary importance for understanding the mode of communication of these cells and their role in brain signaling. We here take advantage of fluorescent tools recently developed for studying recycling of glutamatergic vesicles at synapses (Voglmaier et al., 2006; Balaji and Ryan, 2007); we combine epifluorescence and total internal reflection fluorescence imaging to investigate with unprecedented temporal and spatial resolution, the stimulus-secretion coupling underlying exo-endocytosis of glutamatergic synaptic-like microvesicles (SLMVs) in astrocytes. Our main findings indicate that (1) exo-endocytosis in astrocytes proceeds with a time course on the millisecond time scale (τexocytosis= 0.24 ± 0.017 s; τendocytosis= 0.26 ± 0.03 s) and (2) exocytosis is controlled by local Ca2+microdomains. We identified submicrometer cytosolic compartments delimited by endoplasmic reticulum tubuli reaching beneath the plasma membrane and containing SLMVs at which fast (time-to-peak, ∼50 ms) Ca2+events occurred in precise spatial-temporal correlation with exocytic fusion events. Overall, the above characteristics of transmitter exocytosis from astrocytes support a role of this process in fast synaptic modulation.
Databáze: OpenAIRE
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