Cohen E, Sterling P
J Comp Neurol. 1986 Aug 1;250(1):1-7. doi: 10.1002/cne.902500102.
Cone bipolar neurons in the cat retina were studied in serial sections prepared as electron microscope autoradiograms following intravitreal injection of (3H)glycine. The goal was to learn whether the cone bipolar types that accumulate glycine correspond to the types thought on other grounds to be inhibitory. About half of the cone bipolars in a given patch of retina showed specific accumulation of silver grains. The specificity of accumulation was similar to that shown by glycine-accumulating amacrines. All of the cone bipolars arborizing in sublamina b accumulated glycine but none of the cone bipolars arborizing in sublamina a did so. The types of cone bipolars accumulating glycine did not match the types thought to be inhibitory. Cone bipolar types CBb1 and CBb2 both form gap junctions with the glycine-accumulating AII amacrine, thus raising the possibility that glycine might accumulate in these cone bipolars by diffusion from the AII cell or vice versa. Thus it is logically impossible to tell which of these three cells contains a high-affinity uptake mechanism for glycine and consequently which of the three might actually use glycine as a neurotransmitter.
在向玻璃体内注射（3H）甘氨酸后，制备成电子显微镜放射自显影片的连续切片中，对猫视网膜中的视锥双极神经元进行了研究。目的是了解积累甘氨酸的视锥双极细胞类型是否与基于其他理由被认为具有抑制作用的类型相对应。在给定视网膜区域中，约一半的视锥双极细胞显示出银颗粒的特异性积累。积累的特异性与积累甘氨酸的无长突细胞所显示的相似。所有在b亚层分支的视锥双极细胞都积累甘氨酸，但在a亚层分支的视锥双极细胞均未积累。积累甘氨酸的视锥双极细胞类型与被认为具有抑制作用的类型不匹配。视锥双极细胞类型CBb1和CBb2都与积累甘氨酸的AII无长突细胞形成缝隙连接，因此增加了甘氨酸可能通过从AII细胞扩散而在这些视锥双极细胞中积累的可能性，反之亦然。因此，从逻辑上讲，无法确定这三个细胞中哪个含有甘氨酸的高亲和力摄取机制，因此也无法确定这三个细胞中哪个实际上可能将甘氨酸用作神经递质。
