Kim I B, Lee M Y, Oh S, Kim K Y, Chun M
Department of Anatomy, Catholic University Medical College, 505 Banpo-Dong, Socho-Ku, Seoul 137-701, Korea.
Cell Tissue Res. 1998 Apr;292(1):17-25. doi: 10.1007/s004410051030.
The synaptic connectivity between rod bipolar cells and GABAergic neurons in the inner plexiform layer (IPL) of the rat retina was studied using two immunocytochemical markers. Rod bipolar cells were stained with an antibody specific for protein kinase C (PKC, alpha isoenzyme), and GABAergic neurons were stained with an antiserum specific for glutamic-acid decarboxylase (GAD). Some amacrine cells were also labeled with the anti-PKC antiserum. All PKC-labeled amacrine cells examined showed GABA immunoreactivity, indicating that PKC-labeled amacrine cells constitute a subpopulation of GABAergic amacrine cells in the rat retina. A total of 150 ribbon synapses established by rod bipolar cells were observed in the IPL. One member of the postsynaptic dyads was always an unlabeled AII amacrine cell process, and the other belonged to an amacrine-cell process showing GAD immunoreactivity. The majority (n=92) (61.3%) of these processes made reciprocal synapses back to the axon terminals of rod bipolar cells. In addition, 78 conventional synapses onto rod bipolar axons were observed, and among them 52 (66.7%) were GAD-immunoreactive. Thus GABA provides the major inhibitory input to rod bipolar cells.
利用两种免疫细胞化学标记物研究了大鼠视网膜内网状层（IPL）中视杆双极细胞与GABA能神经元之间的突触连接。视杆双极细胞用针对蛋白激酶C（PKC，α同工酶）的特异性抗体染色，GABA能神经元用针对谷氨酸脱羧酶（GAD）的抗血清染色。一些无长突细胞也用抗PKC抗血清标记。所有检测的PKC标记的无长突细胞均显示GABA免疫反应性，表明PKC标记的无长突细胞构成大鼠视网膜中GABA能无长突细胞的一个亚群。在IPL中观察到视杆双极细胞建立的总共150个带状突触。突触后二元组的一个成员总是一个未标记的AII无长突细胞突起，另一个属于显示GAD免疫反应性的无长突细胞突起。这些突起中的大多数（n = 92）（61.3%）与视杆双极细胞的轴突终末形成相互突触。此外，观察到78个与视杆双极轴突的常规突触，其中52个（66.7%）具有GAD免疫反应性。因此，GABA对视杆双极细胞提供主要的抑制性输入。
