Faculty of Life Sciences, The University of Manchester, Manchester, M13 9PT, UK.
Neurochem Res. 2012 Nov;37(11):2326-38. doi: 10.1007/s11064-012-0765-6. Epub 2012 Apr 3.
Two major neural cell types, glia, astrocytes in particular, and neurones can release chemical transmitters that act as soluble signalling compounds for intercellular communication. Exocytosis, a process which depends on an increase in cytosolic Ca(2+) levels, represents a common denominator for release of neurotransmitters, stored in secretory vesicles, from these neural cells. While neurones rely predominately on the immediate entry of Ca(2+) from the extracellular space to the cytosol in this process, astrocytes support their cytosolic Ca(2+) increases by appropriating this ion from the intracellular endoplasmic reticulum store and extracellular space. Additionally, astrocytes can release neurotransmitters using a variety of non-vesicular pathways which are mediated by an assortment of plasmalemmal channels and transporters. Once a neuronal and/or astrocytic neurotransmitter is released into the extracellular space, it can activate plasma membrane neurotransmitter receptors on neural cells, causing autocrine and/or paracrine signalling. Moreover, chemical transmission is essential not only for homocellular, but also for heterocellular bi-directional communication in the brain. Further detailed understanding of chemical transmission will aid our comprehension of the brain (dys)function in heath and disease.
两种主要的神经细胞类型，胶质细胞，特别是星形胶质细胞，和神经元，可以释放作为细胞间通讯的可溶性信号化合物的化学递质。胞吐作用，一个依赖于细胞溶质 Ca(2+)水平增加的过程，代表了从这些神经细胞中释放储存于分泌小泡中的神经递质的共同特征。虽然神经元在这个过程中主要依赖于细胞外 Ca(2+)的直接进入细胞质，但星形胶质细胞通过从细胞内内质网库和细胞外空间中摄取这种离子来支持其细胞质 Ca(2+)的增加。此外，星形胶质细胞可以使用多种非囊泡途径释放神经递质，这些途径由各种质膜通道和转运体介导。一旦神经元和/或星形胶质细胞的神经递质被释放到细胞外空间，它可以激活神经细胞膜上的神经递质受体，引起自分泌和/或旁分泌信号。此外，化学传递不仅对于同型细胞，而且对于大脑中的异型细胞双向通讯都是至关重要的。进一步详细了解化学传递将有助于我们理解健康和疾病中的大脑（功能）障碍。
