Exocytotic Release of [³H]-Acetylcholine by Ouabain Involves Intracellular Ca²⁺ Stores in Rat Brain Cortical Slices

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• 作者：Lomeo ; Rosangela S. ; Gomez ; Renato S. ; Prado ; Marco Antonio M. ; Romano Silva ; Marco Aur&eacute ; lio ; Massensini ; Andr&eacute ; R. ; Gomez ; Marcus V.
• 关键词：ouabain ; acetylcholine release ; exocytotic ; intracellular calcium
• 刊名：Cellular and Molecular Neurobiology
• 出版年：2003
• 出版时间：2003
• 年：2003
• 卷：23
• 期：6
• 页码：917-927
• 全文大小：625 KB

文摘

1. The effect of ouabain on the release of [³H]acetylcholine ([³H]ACh) in rat brain cortical slices was investigated.

2. The ouabain-induced release of [³H]ACh was calcium-independent and not blocked by EGTA.

3. BAPTA-AM, a chelator of intracellular calcium, inhibited the ouabain effect suggesting the involvement of intracellular calcium stores.

4. Vesamicol, a drug that blocks the storage of acetylcholine in synaptic vesicles inhibited by 73% the ouabain-induced release of [³H]ACh, suggesting exocytotic release of the neurotransmitter.

5. Dantrolene and tetracaine, inhibitors of ryanodine and InP₃ receptors, inhibited by 57 and 66% respectively, the ouabain-elicited release of [³H]ACh in brain cortical slices.

6. Confocal microscopy and calcium imaging showed that ouabain increased the levels of [Ca²⁺]_i in cholinergic SN56 cells and that this increase was concentrated in the cell soma.

7. In conclusion, we suggested that ouabain causes Ca²⁺ release from intracellular stores that can increase [³H]ACh exocytosis from rat brain cortical slices.