Gill J S, Pitts K, Rusnak F M, Owen W G, Windebank A J
Molecular Neuroscience Program, Mayo Clinic and Mayo Foundation, 1501 Guggenheim Building, 200 First Street SW, Rochester, MN 55905, USA. gi
Brain Res. 1998 Jun 29;797(2):321-7. doi: 10.1016/s0006-8993(98)00344-8.
Thrombin is a multifunctional protease. Recent studies on cultured neuronal cells have suggested a function for thrombin in the development and maintenance of the nervous system. Thrombin has been found to induce neurite retraction and reverse stellation in neuroblastoma cell lines and rat astrocytes, respectively. The major focus of our study was to investigate the potential role of thrombin in peripheral nervous system development using the rat embryonic dorsal root ganglion model. We found a dose dependent inhibition of neurite outgrowth from explant dorsal root ganglion cultures upon exposure to 2 to 200 nM thrombin. This effect was reversed by the specific thrombin inhibitor, hirudin. A synthetic peptide that imitates the fully active receptor, thrombin receptor activating peptide, was also found to inhibit neurite outgrowth from dorsal root ganglia. bis-Benzimide stained neuronal cultures did not show any evidence of cell death after exposure to thrombin or thrombin receptor activating peptides. Immunohistochemical studies revealed specific staining of the thrombin receptor on neurons, with intense labeling along neurites. Enriched neuronal cultures exposed to thrombin and thrombin receptor activating peptides revealed rapid activation of phospholipase Cgamma-1, a second messenger associated with the thrombin receptor. These findings are the first to describe the localization of the thrombin receptor to dorsal root ganglion neurons. We propose that receptor activation is associated with thrombin induced inhibition of neurite outgrowth.
凝血酶是一种多功能蛋白酶。最近对培养的神经元细胞的研究表明，凝血酶在神经系统的发育和维持中具有一定作用。已发现凝血酶分别在神经母细胞瘤细胞系和大鼠星形胶质细胞中诱导神经突回缩和逆转星状化。我们研究的主要重点是使用大鼠胚胎背根神经节模型来研究凝血酶在周围神经系统发育中的潜在作用。我们发现，将外植背根神经节培养物暴露于2至200 nM凝血酶后，神经突生长受到剂量依赖性抑制。这种作用可被特异性凝血酶抑制剂水蛭素逆转。还发现一种模仿完全活性受体的合成肽，即凝血酶受体激活肽，也能抑制背根神经节的神经突生长。用双苯甲酰亚胺染色的神经元培养物在暴露于凝血酶或凝血酶受体激活肽后未显示任何细胞死亡迹象。免疫组织化学研究显示神经元上凝血酶受体有特异性染色，神经突上有强烈标记。暴露于凝血酶和凝血酶受体激活肽的富集神经元培养物显示磷脂酶Cγ-1迅速激活，磷脂酶Cγ-1是一种与凝血酶受体相关的第二信使。这些发现首次描述了凝血酶受体在背根神经节神经元中的定位。我们提出受体激活与凝血酶诱导的神经突生长抑制有关。
