Winkler H
Department of Pharmacology, University of Innsbruck, Austria.
Neurochem Res. 1997 Aug;22(8):921-32. doi: 10.1023/a:1022410506476.
The membrane proteins of adrenergic large dense cored vesicles, in particular those of chromaffin granules, have been characterized in detail. With the exception of the nucleotide carrier all major peptides have been cloned. There has been a controversy whether these vesicles contain antigens like synaptophysin, synaptotagmin and VAMP or synaptobrevin found in high concentration in synaptic vesicles. One can now conclude that large dense core vesicles also contain these peptides although in lower concentrations. The biosynthesis of large dense core vesicles is analogous to that of other peptide secreting vesicles of the regulated pathway. One cannot yet definitely define the biosynthesis of small dense core vesicles which apparently have a very similar membrane composition to that of large dense core vesicles. They may form directly from large dense core vesicles when their membranes have been retrieved after exocytosis. These membranes may become sorted in an endosomal compartment where peptides may be deleted or added. Such an addition could be derived from synaptophysin-rich vesicles present in adrenergic axons. However small dense core vesicle peptides may also be transported axonally independent of large dense core vesicles. For proving one of these possibilities some crucial experiments have been suggested.
肾上腺素能大致密核心囊泡的膜蛋白，尤其是嗜铬粒蛋白的膜蛋白，已得到详细表征。除核苷酸载体外，所有主要肽段均已被克隆。这些囊泡是否含有在突触小泡中高浓度存在的诸如突触素、突触结合蛋白和VAMP或突触小泡蛋白等抗原一直存在争议。现在可以得出结论，大致密核心囊泡也含有这些肽段，尽管浓度较低。大致密核心囊泡的生物合成与调节途径中其他肽分泌囊泡的生物合成类似。目前还不能明确界定小致密核心囊泡的生物合成，其膜组成显然与大致密核心囊泡非常相似。当它们的膜在胞吐作用后被回收时，它们可能直接从大致密核心囊泡形成。这些膜可能在内体区室中进行分选，在那里肽段可能被删除或添加。这种添加可能来自肾上腺素能轴突中富含突触素的囊泡。然而，小致密核心囊泡肽段也可能独立于大致密核心囊泡进行轴突运输。为了证明这些可能性中的一种，已经提出了一些关键实验。
