Van der Zee E A, Luiten P G
Department of Animal Physiology, University of Groningen, Haren, The Netherlands.
Brain Res. 1994 Aug 1;652(2):263-72. doi: 10.1016/0006-8993(94)90236-4.
This study describes the cellular distribution of muscarinic acetylcholine receptors (mAChRs) in the medial septum (MS), employing the monoclonal antibody M35 raised against purified mAChR-protein. mAChR-positive neurons are found throughout the MS, but are predominantly located in the midline area and in the lateral compartments. The labeled cell bodies are variable in shape and size (largest diameter ranging from 10-30 microns), while both soma and the associated dendritic processes are densely stained for mAChRs. Astrocytes immunoreactive for mAChRs were frequently found associated with the large blood vessels in the midline area. To study the neurotransmitter nature of the mAChR-positive cells, immunofluorescence double-labeling experiments were performed for mAChRs and GABAergic and cholinergic markers. GABAergic cells were identified immunocytochemically using antisera against glutamic acid decarboxylase (GAD), parvalbumin (PARV) or calbindin protein (CaBP). The cholinergic transmitter nature of the mAChR-positive cells was studied using adjacent 8 microns thick serial sections stained immunocytochemically for choline acetyltransferase (ChAT), or histochemically for acetylcholinesterase (AChE). These experiments showed that approximately half (52.3%) of all mAChR-positive cells contain GAD, whereas the other half is cholinergic. Conversely, nearly all GABAergic (98.6%) and cholinergic (96.9%) cells are endowed with mAChRs. GAD-positive terminals were found surrounding mAChR-positive perikarya which were either GAD-positive or GAD-negative, indicating GABAergic innervation on both GABAergic and cholinergic MS neurons. In general, the staining intensity for mAChRs appeared to be considerably higher in GABAergic than in cholinergic neurons, suggesting a stronger cholinergic impact upon the GABAergic neurons. The current anatomical findings contribute to the concept that the MS neurons form a firmly interconnected cell group, in which cholinergic neurotransmission mediated through mAChRs seems to play a significant role.
本研究利用针对纯化的毒蕈碱型乙酰胆碱受体（mAChR）蛋白产生的单克隆抗体M35，描述了内侧隔区（MS）中毒蕈碱型乙酰胆碱受体的细胞分布情况。在整个内侧隔区均发现了mAChR阳性神经元，但主要位于中线区域和外侧区。标记的细胞体形状和大小各异（最大直径范围为10 - 30微米），而胞体和相关的树突状突起均被mAChR密集染色。在中线区域，经常发现对mAChR具有免疫反应性的星形胶质细胞与大血管相关联。为了研究mAChR阳性细胞的神经递质性质，对mAChR与GABA能和胆碱能标志物进行了免疫荧光双标记实验。使用针对谷氨酸脱羧酶（GAD）、小白蛋白（PARV）或钙结合蛋白（CaBP）的抗血清，通过免疫细胞化学方法鉴定GABA能细胞。利用相邻的8微米厚连续切片，通过免疫细胞化学方法对胆碱乙酰转移酶（ChAT）进行染色，或通过组织化学方法对乙酰胆碱酯酶（AChE）进行染色，研究mAChR阳性细胞的胆碱能递质性质。这些实验表明，所有mAChR阳性细胞中约有一半（52.3%）含有GAD，而另一半是胆碱能的。相反，几乎所有的GABA能（98.6%）和胆碱能（96.9%）细胞都具有mAChR。在mAChR阳性核周体周围发现了GAD阳性终末，这些核周体要么是GAD阳性，要么是GAD阴性，表明内侧隔区的GABA能和胆碱能神经元均接受GABA能神经支配。总体而言，GABA能神经元中mAChR的染色强度似乎明显高于胆碱能神经元，这表明胆碱能对GABA能神经元的影响更强。目前的解剖学研究结果支持了内侧隔区神经元形成紧密相互连接的细胞群这一概念，其中通过mAChR介导的胆碱能神经传递似乎起着重要作用。
