Verhaagen J, Zhang Y, Hamers F P, Gispen W H
Rudolf Magnus Institute, Department of Pharmacology, Utrecht University, The Netherlands.
J Neurosci Res. 1993 Jun 1;35(2):162-9. doi: 10.1002/jnr.490350206.
Neurons in the central nervous system regenerate poorly or not at all. In contrast neurons of the peripheral nervous system have the ability to regrow their nerve fibers over considerable distances. Previously it has been suggested that the absence of the reinduction of the expression of growth associated proteins such as B-50 (GAP43) may be an important factor in the differential response of CNS and PNS neurons to injury. We studied B-50(GAP43) mRNA expression following lesioning of a class of CNS neurons, the olfactory bulb mitral cells. Expression of B-50 mRNA in approximately 40% of the mitral cells was upregulated in response to transection of their axons in the lateral olfactory tract (LOT). Enhanced expression persisted for 10 days postlesion but had virtually declined to control levels by 4 weeks after the lesion. A large proportion of the mitral cells gradually degenerated subsequent to LOT transection. Thus a subpopulation of mitral cells maintains their ability to upregulate B-50, a protein characteristic of growing axons, but enhanced B-50 expression is not accompanied by regeneration of the severed LOT.
中枢神经系统中的神经元再生能力很差或完全无法再生。相比之下，外周神经系统的神经元有能力在相当长的距离内重新生长其神经纤维。此前有人提出，诸如B-50（GAP43）等生长相关蛋白的表达未能重新诱导，可能是中枢神经系统和外周神经系统神经元对损伤产生不同反应的一个重要因素。我们研究了一类中枢神经系统神经元——嗅球二尖瓣细胞受损后B-50（GAP43）mRNA的表达情况。约40%的二尖瓣细胞中，B-50 mRNA的表达在其轴突于外侧嗅束（LOT）被横断后上调。损伤后10天内，表达增强持续存在，但在损伤后4周时实际上已降至对照水平。大部分二尖瓣细胞在LOT横断后逐渐退化。因此，二尖瓣细胞的一个亚群保持了上调B-50（一种生长轴突特有的蛋白质）的能力，但B-50表达增强并未伴随切断的LOT再生。
