哇巴因引起的[3H]-乙酰胆碱胞吐释放涉及大鼠脑皮质切片中的细胞内钙储存。

Exocytotic release of [3H]-acetylcholine by ouabain involves intracellular Ca2+ stores in rat brain cortical slices.

Lomeo Rosangela S, Gomez Renato S, Prado Marco Antonio M, Romano-Silva Marco Aurélio, Massensini André R, Gomez Marcus V

Departamento de Farmacologia, ICB, UFMG, Av. Antonio Carlos 6627-Pampulha, 31270-901 Minas Gerais, Belo Horizonte, Brazil.

Cell Mol Neurobiol. 2003 Dec;23(6):917-27. doi: 10.1023/b:cemn.0000005320.06215.80.

Abstract

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.

摘要

研究了哇巴因对大鼠脑皮质切片中[3H]乙酰胆碱（[3H]ACh）释放的影响。2. 哇巴因诱导的[3H]ACh释放不依赖于钙，且不受乙二醇双四乙酸（EGTA）的阻断。3. 细胞内钙螯合剂1,2-双（2-氨基苯氧基）乙烷-N,N,N',N'-四乙酸乙酰甲酯（BAPTA-AM）抑制了哇巴因的作用，提示细胞内钙库参与其中。4. 维生霉素，一种阻断乙酰胆碱在突触小泡中储存的药物，抑制了73%的哇巴因诱导的[3H]ACh释放，提示神经递质通过胞吐作用释放。5. 丹曲林和丁卡因，分别为兰尼碱受体和三磷酸肌醇（InP3）受体的抑制剂，在脑皮质切片中分别抑制了57%和66%的哇巴因诱导的[3H]ACh释放。6. 共聚焦显微镜和钙成像显示，哇巴因增加了胆碱能SN56细胞中的细胞内钙离子（[Ca2+]i）水平，且这种增加集中在细胞体中。7. 总之，我们认为哇巴因导致细胞内钙库释放钙离子，从而增加大鼠脑皮质切片中[3H]ACh的胞吐作用。