大鼠大脑皮质前生长抑素原mRNA神经元的生后早期发育──原位杂交研究

THE EARLY DEVELOPMENT OF THE PREPROSOMATOSTATIN mRNA NEURONS IN CEREBRAL CORTEX OF THE POSTNATAL RAT ──IN SITU HYBRIDIZATION STUDY BY cRNA PROBE

以地高辛标记的前生长抑素原ｃＲＮＡ（Ｐ－Ｐ－ＳＳｃＲＮＡ）探针，用原位杂交技术研究了大鼠大脑皮质ＳＳｍＲＮＡ神经元的生后早期发育，结果显示：１．旧皮质中的梨状皮质，以扣带回皮质为代表的中间皮质和新皮质中均存在ＳＳｍＲＮＡ神经元。２．ＳＳｍＲＮＡ神经元主要位于梨状皮质深层，从生后第１ｄ（Ｐｌ）至生后第５ｄ（Ｐ５）阳性细胞数增多，体积变大，至生后第１０ｄ（Ｐｌ０）细胞数有减少的趋向。３．扣带回皮质的ＳＳ基因表达较为恒定，从Ｐｌ至Ｐｌ０，阳性细胞较均匀地分布于除第１层以外的各层。４．新皮质ＳＳｍＲＮＡ神经元呈特定的板层状分布，生后第１ｄ主要定位于颗粒下层（Ⅴ、Ⅵ层），至Ｐ５～Ｐｌ０，除仍占据颗粒下层外，颗粒上层亦出现较多淡染的阳性细胞。５，在个别大鼠，于生后第１ｄ的新皮质中见到许多特殊阳性束状结构，该束的深部夹杂一些ＳＳｍＲＮＡ神经元。有的细胞突起与束平行，似有沿束向皮质表面迁移的趋势。上述结果表明，出自同一前体原的ＳＳ１４，ＳＳ２８，ＳＳ２８（１～１２）可能均参与鼠脑早期发育的调节。

The early development of the preprosomatostatin mRNA neurons of cerebral cortex in the postnatal rat was studied by using of digoxigenin labelled cRNA(Dig-Ap-cRNA)probe. The SS mRNA neurons were observed in the piriform cortex, cingulate cortex and neocortex. SS mRNA neurons were predominantly localized in the deep layer of piriform cortex. The number and size of positive cells increase from 1st to 5th day(P1 to P5)postnatally, but the number of the SS mRNA neurons tended to diminished from 5th up to l0th day(Pl0) postnatally.SS gene expression was considerably constant in the cingulate cortex from P1 to P l0. The positive cells were distributed in all layers of the cingulate cortex except the layer l. Neocortical SS mRNA neurons presented a peculiar laminar distribution, the cells were mainly located in infragranular layer to P1. From P5 to P10, some SS mRNA neurons also appeared in the supragranular layer.It is of interest to note that many specific positive tract-like structures were found in one rat neocortex on P1. The deep part of the tract contained some SS mRNA neurons and their processes run parallel with the tract-like structure,Some positive neurons seemed to migrate along the tract from the deep layer toward the superfical layer of cortex,The results indicate that SS14,SS28,SS28(1～12)derived from same preprosomatostatin may be involved in the regulation of the rat brain development, during early neonatal period.