递质释放：使用钌红来证明含唾液酸底物的可能作用。

Transmitter release: ruthenium red used to demonstrate a possible role of sialic acid containing substrates.

作者信息

Baux G, Simonneau M, Tauc L

出版信息

J Physiol. 1979 Jun;291:161-78. doi: 10.1113/jphysiol.1979.sp012805.

DOI:10.1113/jphysiol.1979.sp012805

PMID:225472

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC1280893/

Abstract

The possible function of sialic acid-containing substrates (SACS) in synaptic terminals of Aplysia was studied by intracellular injection of ruthenium red and of neuraminidase. 2. Ruthenium red, a dye known to have sialic acid as a molecular target, blocked transmission irreversibly in both cholinergic (buccal ganglion) and non-cholinergic (cerebral ganglion) synapses. 3. An intracellular site of action is likely because much less ruthenium red was necessary to block transmission when it was injected intracellularly than when it was presented by bath perfusion. 4. Ca2+ spikes recorded in the presence of tetrodotoxin or in Na+-free solution were not modified by ruthenium red or neuraminidase injections or perfusions. It is therefore improbable that these substances blocked transmission by blocking voltage-dependent Ca2+ influx. 5. Strong electrotonic depolarization of a pre-synaptic interneurone in the presence of 10(-4) M-tetrodotoxin caused a sustained post-synaptic response, which was abolished by ruthenium red. This result eliminates axonal conduction block as the principal mechanism of ruthenium red action. 6. Post-synaptic responses to ionophoretically applied acetylcholine (ACh) were not modified by bath perfusion of 2 x 10(-2) M-ruthenium red. 7. Biochemical analysis of pools of [3H]ACh was performed after injection of a precursor, [3H]acetate, into an identified interneurone. Ruthenium red appeared to increase significantly the 'free' (cytoplasmic) ACh pool without any change of 'bound' (vesicular) [3H]ACh-pool. 8. A model is proposed in which SACS act as intracellular Ca2+ receptors involved in transmitter release.

摘要

通过向海兔突触终末内注射钌红和神经氨酸酶，研究了含唾液酸底物（SACS）的可能功能。2. 钌红是一种已知以唾液酸为分子靶点的染料，它能不可逆地阻断胆碱能（颊神经节）和非胆碱能（脑神经节）突触的传递。3. 其作用位点可能在细胞内，因为与通过浴灌流给药相比，细胞内注射时阻断传递所需的钌红要少得多。4. 在河豚毒素存在或无钠溶液中记录的Ca2+ 峰不受钌红或神经氨酸酶注射或灌流的影响。因此，这些物质不太可能通过阻断电压依赖性Ca2+ 内流来阻断传递。5. 在10(-4) M河豚毒素存在下，对突触前中间神经元进行强电紧张性去极化会引起持续的突触后反应，而钌红可消除这种反应。这一结果排除了轴突传导阻滞是钌红作用的主要机制。6. 2×10(-2) M钌红的浴灌流不改变对离子电泳施加乙酰胆碱（ACh）的突触后反应。7. 将前体[3H]乙酸盐注射到一个已鉴定的中间神经元后，对[3H]ACh库进行了生化分析。钌红似乎显著增加了“游离”（细胞质）ACh库，而“结合”（囊泡）[3H]ACh库没有任何变化。8. 提出了一个模型，其中SACS作为参与递质释放的细胞内Ca2+ 受体发挥作用。