大鼠中枢神经系统碳酸酐酶Ⅳ免疫细胞化学定位研究

LOCALIZATION OF CARBONIC ANHYDRASE IV IN RAT CENTRAL NERVOUS SYSTEM BY IMMUNOCYTOCHEMISTRY

碳酸酐酶的活性在调节脑脊液生成中起着重要的作用,并且也影响神经的兴奋性和抽搐发作的敏感性。实验用免疫细胞化学方法对中枢神经系统碳酸酐酶Ⅳ的分布进行了定位研究。结果显示:光镜下碳酸酐酶Ⅳ免疫细胞化学阳性产物存在于大脑各部(大脑皮质、海马、纹状体、杏仁体等)、间脑、小脑、中脑、脑桥、延髓和脊髓的毛细血管壁;神经胶质细胞以及脉络丛的毛细血管壁均未见染色。对照试验阴性。碳酸酐酶Ⅳ超微结构定位于毛细血管内皮细胞腔面,染色深,而细胞浆和细胞器阴性。中枢神经系统碳酸酐酶Ⅳ特异性分布,表明碳酸酐酶Ⅳ在CO_2和HCO_3^-的输送中以及调节脑内酸碱平衡中起重要作用,可能与血脑屏障有关。

Carbonic anhydrase (CA) activity has a significant effect on the production of cerebrospinal fluid and also on the stimulation of nerves and their susceptibility to seizures. The present study focuses on the localization of carbonic anhydrase Ⅳ in the central nervous system in rats with the immunocytochemical method. The result showed that at the light microscopic level the immunoperoxidase reaction product of CA Ⅳ was distributed in the capillaries of the cerebrum (cerebral cortex, hippocapus. corpus striatum amygdaloid body and so on), diencephalon. cerebellum. midbrain, pons, medulla oblongata and spinal cord. Capillaries in these regions were intensely stained while neuroghal cells and the capillaries of the chroid plexus were unstained. Control sections showed negative reaction. By electron microscopy CA Ⅳ could be clearly localized on the lumminal side of the capillary endothelial cells whereas the cytoplasm. cytoplasmic organelles were negative. The specific localization of CA Ⅳ in the central nervous system indicates that CA Ⅳ plays an important role in regulating the electrolyte and acid-balance. CA Ⅳ can be considered an enzyme associated with the blood-brain-barrier.