Abteilung für Allgemeine Zoologie, FB Biologie, TU Kaiserslautern, Postfach 3049, 67653 Kaiserslautern, Germany.
Cerebellum. 2012 Mar;11(1):62-70. doi: 10.1007/s12311-010-0196-3.
Extracellular purines exert their action in the nervous system through purinergic neurotransmission and neuromodulatory processes. Among brain areas, efforts have been made to investigate the purinergic modulation of the cerebellar cortex. In addition, the use of granule cells in culture as a neuronal in vitro model provided important information about the implications of purines in mechanisms such as cell survival and differentiation. This short review is focused on the function of purines in the physiology of granule cells in situ and in vitro. In situ, adenosine has been shown to inhibit some of the glutamatergic and GABAergic synaptic inputs to granule cells. The inhibition of GABA input allows an increase in the excitability of the cell while the output (parallel fibers) of granule cells is also down-regulated by adenosine, suggesting a complex mode of regulation by purines. In vitro, granule cells have been shown to express members of all classes of purinergic receptors, P2X (ionotropic), P2Y (metabotropic) and adenosine receptors. The specific expression of these receptors and the downstream signaling pathways coupling them to cell survival and growth have been extensively studied.
细胞外嘌呤通过嘌呤能神经递质传递和神经调质过程在神经系统中发挥作用。在脑区中，人们已经努力研究嘌呤对小脑皮层的调制作用。此外，使用培养的颗粒细胞作为体外神经元模型提供了关于嘌呤在细胞存活和分化等机制中的重要信息。这篇简短的综述主要集中在嘌呤在原位和体外颗粒细胞生理学中的作用。在原位，已证明腺苷抑制颗粒细胞的一些谷氨酸能和 GABA 能突触输入。GABA 输入的抑制允许细胞兴奋性增加，而颗粒细胞的输出（平行纤维）也被腺苷下调，表明嘌呤的调节方式复杂。在体外，已证明颗粒细胞表达所有类别的嘌呤能受体，P2X（离子型）、P2Y（代谢型）和腺苷受体。这些受体的特异性表达及其与细胞存活和生长偶联的下游信号通路已得到广泛研究。
