Vilijn M H, Vaysse P J, Zukin R S, Kessler J A
Department of Neurology, Albert Einstein College of Medicine, Bronx, NY 10461.
Proc Natl Acad Sci U S A. 1988 Sep;85(17):6551-5. doi: 10.1073/pnas.85.17.6551.
Expression of preproenkephalin mRNA by developing glia and neurons was examined in cultures of embryonic and neonatal rat brain. Cultured glia from specific regions of embryonic day 17 and neonatal day 1 rat brain were identified as astrocytes on the basis of both morphology and expression of immunoreactivity for glial fibrillary acidic protein. The level of preproenkephalin mRNA in cultured neonatal hypothalamic astrocytes was comparable to levels present in cultured embryonic striatal and hypothalamic neurons. Levels of the mRNA were significantly higher in astrocytes derived from neonatal hypothalamus compared to astrocytes derived from other areas of the brain. Thus, there is heterogeneity among astrocytes with respect to preproenkephalin expression. Levels of preproenkephalin mRNA in cultured neonatal striatal astrocytes were only one-third as high as levels in embryonic striatal astrocytes; this observation suggests that glial expression of the gene may be down-regulated during development. Although cultured hypothalamic neurons contained substantial levels of prodynorphin mRNA, levels of this mRNA were not detectable in cultured astrocytes from any brain region or in cultured striatal neurons. Thus, glia do not express all opioid peptide genes during development. These observations suggest that expression of the preproenkephalin gene by astrocytes may play a role in development of the brain.
在胚胎和新生大鼠脑培养物中检测了前脑啡肽原mRNA在发育中的神经胶质细胞和神经元中的表达。根据形态学和胶质纤维酸性蛋白免疫反应性的表达，将来自胚胎第17天和新生第1天大鼠脑特定区域的培养神经胶质细胞鉴定为星形胶质细胞。培养的新生下丘脑星形胶质细胞中前脑啡肽原mRNA的水平与培养的胚胎纹状体和下丘脑神经元中的水平相当。与来自脑其他区域的星形胶质细胞相比，来自新生下丘脑的星形胶质细胞中该mRNA的水平显著更高。因此，星形胶质细胞在前脑啡肽表达方面存在异质性。培养的新生纹状体星形胶质细胞中前脑啡肽原mRNA的水平仅为胚胎纹状体星形胶质细胞中水平的三分之一；这一观察结果表明该基因的胶质细胞表达在发育过程中可能被下调。尽管培养的下丘脑神经元含有大量的强啡肽原mRNA，但在来自任何脑区域的培养星形胶质细胞或培养的纹状体神经元中均未检测到该mRNA的水平。因此，神经胶质细胞在发育过程中并不表达所有的阿片肽基因。这些观察结果表明星形胶质细胞表达前脑啡肽原基因可能在脑的发育中起作用。
