大鼠腰髓背角星形胶质细胞对外伤性疼痛刺激的反应及其与神经元关系的免疫电镜研究

RESPONSE OF THE ASTROCYTES IN RAT LUMBAR SPINAL DORSAL HORN TO TRAUMATIC NOCICEPTIVE STIMULI AND ITS RELATIONSHIP WITH THE NEURONS-AN IMMUNO-ELECTRON-MICROSCOPIC STUDY

本研究采用抗缝隙连接蛋白 43 ( Cx43 )和抗缝隙连接蛋白 3 2 ( Cx3 2 )免疫电镜双标记方法 ,观察了一侧胫、腓骨骨折后大鼠腰髓背角星形胶质细胞与神经元的超微结构改变。结果发现 ,在脊髓背角星形胶质细胞与神经元之间的结合区域存在着如下的超微结构 :( 1)轴突终末直接与星形胶质细胞突起 ( Cx43阳性 )形成一种突触样结构 ;( 2 )由神经元突触前膜、突触后膜及星形胶质细胞突起形成的“三方突触结构”;( 3 )星形胶质细胞与星形胶质细胞之间的缝隙连接 ;( 4 )新发现的由一侧的神经元( Cx3 2阳性 )和另一侧的星形胶质细胞突起 ( Cx43阳性 )组成的一种超微结构 ,骨折后此结构数目显著增高 ,可能是缝隙连接的同源结构 ,暂称为异源性缝隙连接。结果提示 :异源性缝隙连接结构可被疼痛刺激激活 。

The ultrastructure and relation of astrocytes and neurons in dorsal horn of rat spinal cord after the unilateral tibia and fibula bone fracture were observed by using double immuno electron microscopic method. A new type of specialized ultrastructures at the junction areas between astrocytes and neurons within the dorsal horn of lumbar spinal cord were found. It consisted of the astrocytic process on one side and the neuronal dendrites on the other side, and had the cytomembrane thickening and dark staining, with a narrow cleft between both membranes. Connexin32 like immunoreactivity( LI) and connexin43 LI appeared in the neuron side and astrocyte side, respectively. In the experimental group this ultrastructure was increased notably compared with the control. We considered that the newly found ultrastructure might be an isogenous structure of gap junction, and was transiently called the heterologous gap junction (HGJ). These results suggest that the HGJ might be a functional area involved in signal transmission between the neurons and astrocytes after the stimulation.