Just L, Olenik C, Meyer D K
Department of Pharmacology, Albert-Ludwigs-University, Freiburg, Germany.
Cereb Cortex. 1999 Jun;9(4):332-9. doi: 10.1093/cercor/9.4.332.
There is controversial evidence that neocortical projections to the neostriatum may regulate the neostriatal expression of the proenkephalin (PEnk) gene. Therefore, we have studied PEnk gene expression in organotypic neocortico-neostriatal co-cultures as well as cultures of isolated neostriata. PEnk mRNA was determined with in situ hybridization. Removal of the neocortex caused a time-dependent reduction in the number of neostriatal cells which showed expression of the PEnk gene. A maximal decrease was seen after 3 days. Within 2 days after blockade of glutamate receptors of the NMDA type significantly fewer neostriatal cells expressed the PEnk gene, indicating that NMDA receptors mediated the expression of the gene. In isolated neostriatal slices in which the expression of the PEnk gene had been down-regulated, NMDA increased the number of cells which expressed the gene in a time-dependent manner. Maximal expression was observed after 3 days. This induction was reduced by nimodipine, which blocks L-type Ca2(+)-channels. The slow increase in PEnk gene expression caused by NMDA resembled a recruiting process. It seems to be specific for the neostriatum and may be due to the latter's neuronal organization.
有争议的证据表明，新皮质向新纹状体的投射可能调节脑啡肽原（PEnk）基因在新纹状体中的表达。因此，我们研究了器官型新皮质-新纹状体共培养物以及分离的新纹状体培养物中PEnk基因的表达。通过原位杂交测定PEnk mRNA。去除新皮质导致新纹状体中表达PEnk基因的细胞数量随时间减少。3天后观察到最大减少。在阻断NMDA型谷氨酸受体后2天内，表达PEnk基因的新纹状体细胞明显减少，表明NMDA受体介导了该基因的表达。在PEnk基因表达已下调的分离新纹状体切片中，NMDA以时间依赖性方式增加了表达该基因的细胞数量。3天后观察到最大表达。这种诱导作用被阻断L型Ca2(+)通道的尼莫地平所降低。NMDA引起的PEnk基因表达的缓慢增加类似于一种募集过程。它似乎对新纹状体具有特异性，可能是由于新纹状体的神经元组织所致。
