Somogyi P, Soltész I
Neuroscience. 1986 Dec;19(4):1051-65. doi: 10.1016/0306-4522(86)90122-3.
To identify the putative transmitter of large basket and clutch cells in the cat's visual cortex, an antiserum raised against GABA coupled to bovine serum albumen by glutaraldehyde and a postembedding, electron microscopic immunogold procedure were used. Two basket and four clutch cells were revealed by intracellular injection of horseradish peroxidase. They were identified on the basis of the distribution of their processes and their synaptic connections. Large basket cells terminate mainly in layer III, while clutch cells which have a more restricted axon, terminate mainly in layer IV. Both types of neuron have a small radial projection. They establish type II synaptic contacts and about 20-30% of their synapses are made with the somata of other neurons, the rest with dendrites and dendritic spines. Altogether 112 identified, HRP-filled boutons, the dendrites of three clutch cells and myelinated axons of both basket and clutch cells were tested for the presence of GABA. They were all immunopositive. The postsynaptic neurons received synapses from numerous other GABA-positive boutons in addition to the horseradish peroxidase-filled ones. Dendritic spines that received a synapse from a GABA-positive basket or clutch cell bouton also received a type I synaptic contact from a GABA-negative bouton. A few of the postsynaptic dendrites, but none of the postsynaptic somata, were immunoreactive for GABA. The fine structural characteristics of the majority of postsynaptic targets suggested that they were pyramidal and spiny stellate cells. These results provide direct evidence for the presence of immunoreactive GABA in identified basket and clutch cells and strongly suggest that GABA is a neurotransmitter at their synapses. The laminar distribution of the synaptic terminals of basket and clutch cells demonstrates that some GABAergic neurons with similar target specificity segregate into different laminae, and that the same GABAergic cells can take part in both horizontal and radial interactions.
为了确定猫视觉皮层中大型篮状细胞和扣带细胞的假定递质，使用了一种通过戊二醛与牛血清白蛋白偶联的抗GABA抗血清以及一种包埋后电子显微镜免疫金法。通过细胞内注射辣根过氧化物酶揭示了两个篮状细胞和四个扣带细胞。根据它们的突起分布和突触连接对它们进行了鉴定。大型篮状细胞主要终止于III层，而轴突分布更局限的扣带细胞主要终止于IV层。这两种类型的神经元都有一个小的径向投射。它们形成II型突触联系，约20 - 30%的突触与其他神经元的胞体形成，其余与树突和树突棘形成。总共对112个已鉴定的、充满辣根过氧化物酶的终扣、三个扣带细胞的树突以及篮状细胞和扣带细胞的有髓轴突进行了GABA检测。它们均呈免疫阳性。除了充满辣根过氧化物酶的终扣外，突触后神经元还从许多其他GABA阳性终扣接收突触。从GABA阳性篮状细胞或扣带细胞终扣接收突触的树突棘也从一个GABA阴性终扣接收I型突触联系。少数突触后树突对GABA呈免疫反应，但突触后胞体均无。大多数突触后靶标的精细结构特征表明它们是锥体细胞和棘状星状细胞。这些结果为已鉴定的篮状细胞和扣带细胞中存在免疫反应性GABA提供了直接证据，并强烈表明GABA是它们突触处的神经递质。篮状细胞和扣带细胞突触终末的层状分布表明，一些具有相似靶标特异性的GABA能神经元分隔到不同的层中，并且相同的GABA能细胞可以参与水平和径向相互作用。
