Higgins M J, Hosseinzadeh H, MacGregor D G, Ogilvy H, Stone T W
Department of Pharmacology, University of Glasgow, Scotland.
Pharm World Sci. 1994 Apr 15;16(2):62-8. doi: 10.1007/BF01880657.
Adenosine is released from active neurons into the extracellular fluid at a concentration of about 1 mumol/l. Neither the precise cellular origin nor the biochemical form of release has been firmly established, though the nucleotide is probably released partly directly, as a result of raised intracellular levels, and partly as nucleotides, which are subsequently hydrolysed. Once in the extracellular medium, adenosine markedly inhibits the release of excitatory neurotransmitters and modulatory peptides and has direct inhibitory effects on postsynaptic excitability via A1 receptors. A population of A2 receptors may mediate depolarization and enhanced transmitter release. Adenosine also modulates neuronal sensitivity to acetylcholine and catecholamines, all these effects probably contributing to the behavioural changes observed in conscious animals. As a result of their many actions, adenosine analogues are being intensively investigated for use as anticonvulsant, anxiolytic, and neuroprotective agents.
腺苷从活跃的神经元释放到细胞外液中，浓度约为1微摩尔/升。尽管这种核苷酸可能部分是由于细胞内水平升高而直接释放，部分是以核苷酸形式释放，随后再水解，但确切的细胞来源和释放的生化形式尚未完全确定。一旦进入细胞外介质，腺苷会显著抑制兴奋性神经递质和调节肽的释放，并通过A1受体对突触后兴奋性产生直接抑制作用。一群A2受体可能介导去极化和增强递质释放。腺苷还调节神经元对乙酰胆碱和儿茶酚胺的敏感性，所有这些作用可能都导致了在清醒动物身上观察到的行为变化。由于其多种作用，腺苷类似物正在被深入研究用作抗惊厥、抗焦虑和神经保护剂。
