Martínez A, Ruiz M, Soriano E
Department of Animal and Plant Cell Biology, Faculty of Biology, University of Barcelona, Spain.
J Comp Neurol. 1999 Feb 22;404(4):438-48. doi: 10.1002/(sici)1096-9861(19990222)404:4<438::aid-cne2>3.0.co;2-k.
We have used the Golgi method and Golgi electron microscopic techniques to analyze the axonal arborization and efferent connections of spiny calretinin-immunoreactive neurons in the CA3 region and hilus of the rat hippocampal formation. In the hilus, the axons of spiny calretinin-immunoreactive neurons sent out numerous collaterals that arborized in the hilar region and the molecular layer. In the CA3 region, these axons extended mainly to the stratum radiatum and pyramidal layer but also to the stratum oriens and stratum lacunosum-moleculare. Axonal varicosities were distributed widely throughout the axonal collaterals. Electron microscopic studies revealed that the axon terminals of spiny calretinin-immunoreactive neurons established synaptic contacts mainly with dendritic shafts. We next analyzed the expression of glutamic acid decarboxylase (GAD65/67) mRNAs in spiny nonpyramidal neurons that were identified by calretinin immunoreactivity. We found that spiny calretinin-positive neurons in the CA3 region and hilus of the rat hippocampal formation expressed the two isoforms of GAD: GAD65 and GAD67 mRNAs. These findings show that the spiny calretinin-immunoreactive neurons of hippocampus give rise to local axonal arborizations, suggesting that they are inhibitory.
我们运用高尔基方法和高尔基电子显微镜技术，分析了大鼠海马结构CA3区和齿状回中棘状钙视网膜蛋白免疫反应性神经元的轴突分支和传出连接。在齿状回中，棘状钙视网膜蛋白免疫反应性神经元的轴突发出大量侧支，这些侧支在齿状回区域和分子层形成分支。在CA3区，这些轴突主要延伸至辐射层和锥体细胞层，但也延伸至原层和腔隙-分子层。轴突膨体广泛分布于轴突侧支上。电子显微镜研究显示，棘状钙视网膜蛋白免疫反应性神经元的轴突终末主要与树突干建立突触联系。接下来，我们分析了通过钙视网膜蛋白免疫反应性鉴定的棘状非锥体神经元中谷氨酸脱羧酶（GAD65/67）mRNA的表达情况。我们发现，大鼠海马结构CA3区和齿状回中棘状钙视网膜蛋白阳性神经元表达GAD的两种同工型：GAD65和GAD67 mRNA。这些发现表明，海马中棘状钙视网膜蛋白免疫反应性神经元产生局部轴突分支，提示它们具有抑制性。
