Rathbone Michel, Pilutti Lara, Caciagli Francesco, Jiang Shucui
Department of Medicine-Neurology, McMaster University, Hamilton, Canada.
Nucleosides Nucleotides Nucleic Acids. 2008 Jun;27(6):666-72. doi: 10.1080/15257770802143913.
Central nervous system (CNS) astrocytes release guanosine extracellularly, that exerts trophic effects. In CNS, extracellular guanosine (GUO) stimulates mitosis, synthesis of trophic factors, and cell differentiation, including neuritogenesis, is neuroprotective, and reduces apoptosis due to several stimuli. Specific receptor-like binding sites for eGUO in the nervous system may mediate its effects through both MAP kinase and PI3-kinase signalling pathways. Extracellular guanine (eGUA) also exerts several effects; the trophic effects of eGUO are likely regulated by conversion of eGUO to eGUA by a membrane located purine nucleoside phosphorylase (ecto-PNP) and by conversion of eGUA to xanthine by guanine deaminase.
中枢神经系统（CNS）星形胶质细胞在细胞外释放鸟苷，其具有营养作用。在中枢神经系统中，细胞外鸟苷（GUO）可刺激有丝分裂、营养因子的合成以及细胞分化，包括神经突形成，具有神经保护作用，并可减少多种刺激引起的细胞凋亡。神经系统中细胞外鸟苷（eGUO）的特异性受体样结合位点可能通过丝裂原活化蛋白激酶（MAP激酶）和磷脂酰肌醇-3激酶（PI3激酶）信号通路介导其作用。细胞外鸟嘌呤（eGUA）也具有多种作用；eGUO的营养作用可能受位于细胞膜的嘌呤核苷磷酸化酶（ecto-PNP）将eGUO转化为eGUA以及鸟嘌呤脱氨酶将eGUA转化为黄嘌呤的调控。
