Pirvola U, Cao Y, Oellig C, Suoqiang Z, Pettersson R F, Ylikoski J
Department of Pathology, University of Helsinki, Finland.
Proc Natl Acad Sci U S A. 1995 Sep 26;92(20):9269-73. doi: 10.1073/pnas.92.20.9269.
Here we show that the mature cochlear neurons are a rich source of acidic fibroblast growth factor (aFGF), which is expressed in the neuronal circuitry consisting of afferent and efferent innervation. The site of action of neuronal aFGF is likely to reside in the organ of Corti, where one of the four known FGF receptor (FGFR) tyrosine kinases--namely, FGFR-3 mRNA--is expressed. Following acoustic overstimulation, known to cause damage to the organ of Corti, a rapid up-regulation of FGFR-3 is evident in this sensory epithelium, at both mRNA and protein levels. The present results provide in vivo evidence for aFGF being a sensory neuron-derived, anterogradely transported factor that may exert trophic effects on a peripheral target tissue. In this sensory system, aFGF, rather than being a neurotrophic factor, seems to promote maintenance of the integrity of the organ of Corti. In addition, aFGF, released from the traumatized nerve endings, may be one of the first signals initiating protective recovery and repair processes following damaging auditory stimuli.
在此我们表明，成熟的耳蜗神经元是酸性成纤维细胞生长因子（aFGF）的丰富来源，该因子在由传入和传出神经支配组成的神经回路中表达。神经元aFGF的作用位点可能位于柯蒂氏器，在那里四种已知的成纤维细胞生长因子受体（FGFR）酪氨酸激酶之一——即FGFR - 3 mRNA——被表达。在已知会对柯蒂氏器造成损伤的声学过度刺激后，在该感觉上皮中，FGFR - 3在mRNA和蛋白质水平上均有明显的快速上调。目前的结果为aFGF是一种感觉神经元衍生的、顺行运输的因子提供了体内证据，该因子可能对周围靶组织发挥营养作用。在这个感觉系统中，aFGF似乎并非神经营养因子，而是促进柯蒂氏器完整性的维持。此外，从受损神经末梢释放的aFGF可能是在有害听觉刺激后启动保护性恢复和修复过程的首批信号之一。
