Morris B J, Reimer S, Höllt V, Herz A
Department of Neuropharmacology, Max-Planck-Institut für Psychiatrie, Planegg-Martinsried, F.R.G.
Brain Res. 1988 Aug;464(1):15-22. doi: 10.1016/0169-328x(88)90013-7.
Peptides derived from proenkephalin and prodynorphin are known to be located in striatal projection neurones. Anatomical studies have shown the presence of a major serotonergic projection from the dorsal raphe nucleus to the striatum, although the function of this pathway is unknown. We have used in situ nucleic acid hybridization to investigate a possible role of this serotonergic innervation in the regulation of striatal opioid gene expression. The levels of proenkephalin mRNA and prodynorphin mRNA were determined in rat striatum and nucleus accumbens. Destruction of the dorsal raphe nucleus by microinjection of 5,7-dihydroxytryptamine failed to affect the levels of proenkephalin mRNA in any region. However, the levels of prodynorphin mRNA were significantly reduced in the medial nucleus accumbens and caudomedial striatum. This implies that activity in the raphe-striatal serotonin pathway mediates a tonic and selective enhancement of prodynorphin gene expression in the striatal target cells. This is in contrast to the tonic suppression of proenkephalin gene expression mediated by the mesostriatal dopamine pathway.
已知源自脑啡肽原和强啡肽原的肽位于纹状体投射神经元中。解剖学研究表明，存在从背侧中缝核到纹状体的主要5-羟色胺能投射，尽管该通路的功能尚不清楚。我们使用原位核酸杂交来研究这种5-羟色胺能神经支配在纹状体阿片样物质基因表达调节中的可能作用。测定了大鼠纹状体和伏隔核中脑啡肽原mRNA和强啡肽原mRNA的水平。通过微量注射5,7-二羟基色胺破坏背侧中缝核未能影响任何区域的脑啡肽原mRNA水平。然而，伏隔核内侧和尾内侧纹状体中的强啡肽原mRNA水平显著降低。这意味着中缝-纹状体5-羟色胺通路的活动介导了纹状体靶细胞中强啡肽原基因表达的紧张性和选择性增强。这与中脑-纹状体多巴胺通路介导的脑啡肽原基因表达的紧张性抑制形成对比。
