Dally J J, Schaefer M, Greenfield S A
University Department of Pharmacology, Oxford, U.K.
Neurochem Int. 1996 Dec;29(6):629-35. doi: 10.1016/s0197-0186(96)00057-5.
Acetylcholinesterase release in the guinea-pig substantia nigra has been previously investigated 'on-line', using a sensitive chemiluminescent system. Since histological observations suggest that there is a difference in acetylcholinesterase distribution in the rat substantia nigra compared to that of the guinea-pig, the first aim of the present study was to use this chemiluminescent method to characterise acetylcholinesterase release in this brain region of the freely moving rat, and the second was explore the relationship between acetylcholinesterase release and dopamine systems in this region. Accordingly, acetylcholinesterase release in the rat substantia nigra was studied under basal conditions of spontaneous release and following the local administration of (a) elevated potassium ions (30, 45, 60'mM), (b) a stimulator of dopamine/acetylcholinesterase release-D-amphetamine (10(-7), 10(-6) and 10(-5) M), (c) an inhibitor of dopamine uptake-GBR12909 (10(-7), 10(-6) and 10(-5) M). Spontaneous release of acetylcholinesterase in this brain region of the rat appears to be comparable with that observed in the guinea-pig, despite the smaller number of acetylcholinesterase-containing neurones. Furthermore, not only elevated potassium ions, but D-amphetamine as well as GBR12909, all produced significant increases in the percentage spontaneous release of acetylcholinesterase. Thus, the release of acetylcholinesterase in this region may be triggered by levels of dopamine outside of the neurone.
先前已使用灵敏的化学发光系统对豚鼠黑质中的乙酰胆碱酯酶释放进行了“在线”研究。由于组织学观察表明，与豚鼠相比，大鼠黑质中的乙酰胆碱酯酶分布存在差异，因此本研究的首要目标是使用这种化学发光方法来表征自由活动大鼠该脑区中乙酰胆碱酯酶的释放，其次是探究该区域中乙酰胆碱酯酶释放与多巴胺系统之间的关系。因此，在自发释放的基础条件下以及在局部施用以下物质后，研究了大鼠黑质中乙酰胆碱酯酶的释放：(a) 升高的钾离子（30、45、60 mM），(b) 多巴胺/乙酰胆碱酯酶释放刺激剂——右旋苯丙胺（10^(-7)、10^(-6) 和 10^(-5) M），(c) 多巴胺摄取抑制剂——GBR12909（10^(-7)、10^(-6) 和 10^(-5) M）。尽管含乙酰胆碱酯酶的神经元数量较少，但大鼠该脑区中乙酰胆碱酯酶的自发释放似乎与豚鼠中观察到的相当。此外，不仅升高的钾离子，而且右旋苯丙胺以及 GBR12909 均使乙酰胆碱酯酶的自发释放百分比显著增加。因此，该区域中乙酰胆碱酯酶的释放可能由神经元外的多巴胺水平触发。
