SNAP-25 Modulation of Calcium Dynamics Underlies Differences in GABAergic and Glutamatergic Responsiveness to Depolarization

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• 作者：Claudia Verderio ; Davide Pozzi ; Elena Pravettoni ; Francesca Inverardi ; Ursula Schenk ; Silvia Coco ; Vé ; ronique Proux-Gillardeaux ; Thierry Galli ; Ornella Rossetto ; Carolina Frassoni and Mi
• 刊名：Neuron
• 出版年：2004
• 出版时间：19 February 2004
• 年：2004
• 卷：41
• 期：4
• 页码：599-610
• 全文大小：1671 K

文摘

SNAP-25 is a component of the SNARE complex implicated in synaptic vesicle exocytosis. In this study, we demonstrate that hippocampal GABAergic synapses, both in culture and in brain, lack SNAP-25 and are resistant to the action of botulinum toxins type A and E, which cleave this SNARE protein. Relative to glutamatergic neurons, which express SNAP-25, GABAergic cells were characterized by a higher calcium responsiveness to depolarization. Exogenous expression of SNAP-25 in GABAergic interneurons lowered calcium responsiveness, and SNAP-25 silencing in glutamatergic neurons increased calcium elevations evoked by depolarization. Expression of SNAP-25_1-197 but not of SNAP-25_1-180 inhibited calcium responsiveness, pointing to the involvement of the 180–197 residues in the observed function. These data indicate that SNAP-25 is crucial for the regulation of intracellular calcium dynamics and, possibly, of network excitability. SNAP-25 is therefore a multifunctional protein that participates in exocytotic function both at the mechanistic and at the regulatory level.