West M J, Ostergaard K, Andreassen O A, Finsen B
Institute of Anatomy, University of Aarhus, Denmark.
J Comp Neurol. 1996 Jun 17;370(1):11-22. doi: 10.1002/(SICI)1096-9861(19960617)370:1<11::AID-CNE2>3.0.CO;2-O.
Somatostatin-containing neurons of the striatum constitute fewer than 5% of the total neuronal population. Their involvement in the feedforward inhibition of the spiny projection neurons, the modulation of other interneurons, and the regulation of regional blood flow indicates that this small population of neurons plays an important role in the processing of information in the striatum. As a first step in developing a quantitative structural framework within which a more rigorous analysis can be made of the functional circuitry of the striatum, we used modern unbiased stereological techniques to make estimates of the total number of neurons expressing mRNA for somatostatin in the striatum of rats. The strategy developed involved the application of the optical fractionator technique to relatively thick tissue sections that were hybridized in situ with a relatively short oligonucleotide probe conjugated to a nonradioactive reporter molecule. The approach is generally applicable to other subpopulations of in situ hybridized cells in other parts of the brain and can provide a link between molecular neurobiology and stereology. The mean total number of neurons on one side of the striatum was estimated to be 21,300. An analysis of the sampling scheme indicated that counting no more than 200 neurons in a systematic sample of not more than 15 sections per individual results in an estimate with a precision that is more than sufficient for comparative and experimental studies. The issues that must be considered when analyzing in situ hybridized tissue with modern stereological methods, the interpretive caveats inherent in the resulting data, and the unique perspectives provided by data like that presented here for striatal somatostatin neurons are discussed.
纹状体中含生长抑素的神经元占神经元总数不到5%。它们参与棘状投射神经元的前馈抑制、对其他中间神经元的调节以及区域血流的调控，这表明这一小部分神经元在纹状体的信息处理中发挥着重要作用。作为建立定量结构框架的第一步，以便能更严格地分析纹状体的功能回路，我们使用现代无偏立体学技术来估计大鼠纹状体中表达生长抑素mRNA的神经元总数。所开发的策略包括将光学分选技术应用于相对较厚的组织切片，这些切片与结合了非放射性报告分子的相对短的寡核苷酸探针进行原位杂交。该方法一般适用于大脑其他部位原位杂交细胞的其他亚群，并且能在分子神经生物学和立体学之间建立联系。估计纹状体一侧的神经元平均总数为21,300个。对抽样方案的分析表明，在每个个体不超过15个切片的系统样本中计数不超过200个神经元，所得到的估计精度对于比较和实验研究来说绰绰有余。本文讨论了用现代立体学方法分析原位杂交组织时必须考虑的问题、所得数据中固有的解释性注意事项，以及像这里呈现的关于纹状体生长抑素神经元的数据所提供的独特观点。
