Figure 6.

GABA-immunoreactive neuron with output synapses. Details from one out of four consecutive immunogold-labeled sections through the CBL near its dorsal boundary with the CBU. Dilution of the GABA antiserum 1:4000. The GABA-immunoreactive neuron (GN) makes four output synapses (s1-s4) with non-classified small profiles (A–D; asterisks) surrounding GN. Arrowheads point to presynaptic densities. All synapses are of type I. The small profiles B and C receive dual synaptic input. Both profiles are, in addition, postsynaptic to another probably also GABA-immunolabeled profile E. Arrow points to presynaptic density. One of the postsynaptic profiles at s3 and s4, respectively, contains granular dense core vesicles (D, right asterisk). The mean GP densities (n = 4) were 10.1 ± 4.0 GP/μm² (GN), 1.3 ± 0.7 GP/μm² for the profile NN, and 0.8 ± 0.7 GP/μm² for a second unlabeled profile (not shown). The GP density in GN was significantly different from those of the two other profiles (one-way ANOVA, Tukey-HSD, p < 0.05). Scale bar: 1 μm.