弱视猫外侧膝状体γ－氨基丁酸能神经元变化的免疫细胞化学研究

Experimental studies on the changes of immunocy-tochelnistry of γ-aminobutyric acidergic neurons in thelateral geniculate nuclei of amblyopic kittens

以２～４周龄幼猫制作单眼剥夺弱视模型。应用ＰＶＥＰ对比手术前及饲养１２周后的视觉变化。在证实动物产生弱视后，冠状切取外侧膝状体（ｌａｔｅｒａｌｇｅｎｉｃｕｌａｔｅｎｕｃｌｅｕｓ，ＬＧＮ），对其γ－氨基丁酸（ｇａｍａ－ａｍｉｎｏｂｕｔｙｒｉｃａｃｉｄ，ＧＡＢＡ）能神经元行免疫细胞化学ＡＢＣ技术处理，由计算机图像分析对照组正常眼和实验组剥夺眼对侧ＬＧＮ的Ａ，Ａ＿１和Ｃ层ＧＡＢＡ免疫阳性神经元数量和灰度变化。结果表明，幼猫的ＬＧＮ三层均有ＧＡＢＡ能神经元分布，与对照组比较，剥夺眼输入层的ＧＡＢＡ免疫阳性神经元的数量、灰度显著降低。提示：（１）ＬＧＮ的ＧＡＢＡ能神经元在幼猫生后早期视觉发育中，对视剥夺具有敏感性，其活性依赖有无正常视觉信息输入及视网膜功能如何。（２）ＧＡＢＡ能神经元对视信号输入和处理起调制作用。

Abstract 14 kittens at 2～4weeks of age were randornly di-vided into normal (N)and monocular deprived ( MD )groups. Before the MD amblyopic models were made,pattern visual evoked potentials(PVEPs)were elicitedfrom the experimental eyes. After the closure of 7 uni-lateral eyes(right 3, left 4 )with operation,the twokitten groups were fed for 12 weeks under a same visualenvironment. At the end of 12 weeks, PVEPs were re-examined and amblyopia was confirmed in the MDgroup.The γ-aminobutyric acidergic(GABAergic)neu-rons in the layers A, A_1 and C in the contralateral genic-ulate nucleus (CLGN) inputs from N and MD eyes werestained with antibiotin-peroxidase complex(ABC)method.The changes in number and grey degree ofGABA imrnunopositive neurons in the lavers A ,A_1 andC in CLGN inputs from N and MD eves were analvsedby a computer image analysis system. The results showthat GABA immunopositive neurons are reduced innumber and their grey degree is decreased in the layerinputs from MD eyes in the comparisonsbetween thelayers of inputs from MD and N eyes. The experimentindicates that(1) GABAergic neurons in thekitten lat-eral geniculate nucleus (LGN ) are susceptible to visualdeprivation during the postnatal critical period and theirfunctions are dependent on the import of visual sense in-formation and the retinal activity.(2)GABAergic neu-rons in the LGN act as regulators in dealing with andimporting visual signal toward striate cortex.