Hattori T, Takei N, Mizuno Y, Kato K, Kohsaka S
Department of Neurochemistry, National Institute of Neuroscience, Tokyo, Japan.
Neurosci Res. 1995 Jan;21(3):191-8. doi: 10.1016/0168-0102(94)00849-b.
We previously reported that the gamma gamma-isozyme of enolase, NSE), one of the glycolytic enzymes, promoted the survival of embryonic rat neocortical neurons in culture, but alpha alpha-isozyme (non-neuronal enolase) had no effect. In the present study, the neurotrophic effects of NSE on cultured mesencephalic and spinal neurons from rat embryo were examined. NSE promoted the survival of neurons not only in neocortical cultures but also in mesencephalic and spinal cord cultures. Furthermore, NSE showed neuroprotective action on cultured neocortical neurons in a low-oxygen atmosphere. By contrast, non-neuronal enolase did not show any neurotrophic or neuroprotective activities. To clarify the mechanism of the neurotrophic effect of NSE, the binding of NSE to cultured neurons was determined by radio-receptor assay using 125I-labelled NSE. The specific binding, which was dose-dependent, saturable, and calcium-dependent, could be detected. These results suggest that NSE has neurotrophic and neuroprotective effects on rather a broad spectrum of neurons in the central nervous system. The existence of specific binding of NSE to cultured neurons suggests the possibility that receptor-like or carrier-like molecules on the neuronal surface are involved in the neurotrophic activity of NSE.
我们之前报道过，烯醇化酶的γγ同工酶（神经元特异性烯醇化酶，NSE），作为糖酵解酶之一，可促进培养的胚胎大鼠新皮质神经元的存活，但αα同工酶（非神经元烯醇化酶）则无此作用。在本研究中，检测了NSE对大鼠胚胎中脑和脊髓培养神经元的神经营养作用。NSE不仅能促进新皮质培养物中神经元的存活，还能促进中脑和脊髓培养物中神经元的存活。此外，NSE在低氧环境下对培养的新皮质神经元具有神经保护作用。相比之下，非神经元烯醇化酶未表现出任何神经营养或神经保护活性。为阐明NSE神经营养作用的机制，通过使用125I标记的NSE进行放射受体分析来测定NSE与培养神经元的结合。可检测到特异性结合，其具有剂量依赖性、饱和性且依赖于钙。这些结果表明，NSE对中枢神经系统中相当广泛的神经元具有神经营养和神经保护作用。NSE与培养神经元的特异性结合的存在表明，神经元表面的受体样或载体样分子可能参与了NSE的神经营养活性。
