Hansson E
Institute of Neurobiology, University of Göteborg, P.O. Box 33 031, S-400 33 Göteborg, Sweden.
Neurochem Int. 1990;16(3):237-45. doi: 10.1016/0197-0186(90)90097-d.
Previously assumed as passive structural and metabolic support elements for the neurons, astrocytes are now considered to have key roles in normal physiology, in brain development and in the pathology of the nervous system. Using culture techniques it has been demonstrated that astroglia express receptors functionally coupled to second messenger systems, previously thought to be exclusively localized to neurons. Furthermore, the cells possess uptake carriers for amino acid neurotransmitters and enzyme systems for inactivation of several neurotransmitters. They can also regulate the extracellular ionic milieu including a clearing of K(+) from the extracellular space. With these specific functional characteristics and their strategic anatomy the cells might influence the passage of information between neurons. Data are accumulating that astrocytes are a heterogeneous class of cells both in terms of morphology, surface properties and in their distribution within the central nervous system. Taking such a heterogeneity into account, especially with respect to the expression of membrane receptors astroglia may be able to respond selectively to changes in their humoral environment which may provide new therapeutic approaches. In this acticle some data are presented, predominantly from experiments on primary cultures, on astroglial heterogeneity. Functional implications of such a heterogeneity are discussed.
星形胶质细胞以前被认为是神经元的被动结构和代谢支持元件，现在被认为在正常生理学、脑发育和神经系统病理学中起关键作用。利用培养技术已证明，星形胶质细胞表达与第二信使系统功能偶联的受体，而第二信使系统以前被认为仅存在于神经元中。此外，这些细胞拥有氨基酸神经递质的摄取载体和多种神经递质失活的酶系统。它们还可以调节细胞外离子环境，包括从细胞外空间清除钾离子。凭借这些特定的功能特性及其重要的解剖结构，这些细胞可能会影响神经元之间的信息传递。越来越多的数据表明，星形胶质细胞在形态、表面特性及其在中枢神经系统中的分布方面都是一类异质性细胞。考虑到这种异质性，特别是关于膜受体的表达，星形胶质细胞可能能够对其体液环境的变化做出选择性反应，这可能提供新的治疗方法。在本文中，主要从原代培养实验中给出了一些关于星形胶质细胞异质性的数据，并讨论了这种异质性的功能意义。
