Nastuk M A, Graybiel A M
Department of Brain and Cognitive Science, Whitaker College of Health Science, Technology and Management, Massachusetts Institute of Technology, Cambridge, 02139.
J Neurosci. 1988 Mar;8(3):1052-62. doi: 10.1523/JNEUROSCI.08-03-01052.1988.
The autoradiographic distribution of M1 and M2 muscarinic cholinergic binding sites was studied in the striatum of the cat, monkey, and human, and concurrent binding assays were carried out on striatal tissue sections from the cat. M1 sites were directly labeled with 3H-pirenzepine; M2 sites were labeled as a consequence of binding competition between pirenzepine and 3H-N-methylscopolamine. Serial section analysis with autoradiograms and stained tissue sections allowed for comparisons among M1 and M2 binding distributions and AChE staining patterns. The 2 subtypes of binding sites demonstrated distinct striatal distributions. M2 sites were virtually homogeneous except in the ventral striatum, where zones of sparse and especially dense binding were observed. Striatal M1 sites were generally more abundant than M2 sites and showed similar heterogeneity in the ventral striatum. Dorsally, however, patches of dense M1 binding were found, and proved to correspond with AChE-poor striosomes, hallmarks of striatal compartmentalization. The finding of differing distributions for the 2 subtypes of muscarinic cholinergic binding sites suggests a mechanism for the intrinsic spatial segregation of striatal cholinergic function. Further, the striosomal patterning of M1 binding indicates that certain aspects of cholinergic function in the striatum may be constrained and thus regulated by the compartmental ordering characteristic of this region of the basal ganglia.
研究了猫、猴和人的纹状体中M1和M2毒蕈碱胆碱能结合位点的放射自显影分布，并对猫的纹状体组织切片进行了同步结合测定。M1位点用3H-哌仑西平直接标记；M2位点是由于哌仑西平和3H-N-甲基东莨菪碱之间的结合竞争而被标记。通过放射自显影图和染色组织切片的连续切片分析，可以比较M1和M2结合分布以及乙酰胆碱酯酶（AChE）染色模式。这两种结合位点亚型表现出不同的纹状体分布。M2位点几乎是均匀的，除了在腹侧纹状体中观察到结合稀疏和特别密集的区域。纹状体M1位点通常比M2位点更丰富，并且在腹侧纹状体中表现出类似的异质性。然而，在背侧发现了密集M1结合的斑块，并且证明与AChE缺乏的纹状体小体相对应，纹状体小体是纹状体分区的标志。毒蕈碱胆碱能结合位点的两种亚型分布不同，这一发现提示了纹状体胆碱能功能内在空间隔离的机制。此外，M1结合的纹状体小体模式表明，纹状体中胆碱能功能的某些方面可能受到限制，从而受到基底神经节该区域分区有序性的调节。
