Fig. 4. Dendritic and subsynaptic localization of GlyR α1 subunit mRNAs. A–C, Examples of optical sections of dendrites obtained with a confocal microscope (pixel size, 0.1 μm). In most cases, the mRNAs (red) were predominantly at the neurite periphery, here outlined by GlyR immunoreactivity (green; arrows), as seen on longitudinal (A) or transversal (B) views. Note that the mRNAs tend to form aggregates (arrowheads) within dendrites. In some dendrites (C), the mRNAs appear evenly distributed throughout the dendritic cross section. Colocalization of mRNA signal with GlyR immunoreactivity (yellow;A–C). D, EM ISH of mRNAs visualized in dendrites by HRP reaction product showing their tendency to accumulate peripherally to the dendritic center, and in front of synapses (arrows). Within dendrites, the mRNA signal is discontinuous and forms aggregates (arrowheads).E, The mRNAs detected by gold labeling (arrowheads) at the dendritic periphery are next to synapses. F, Decoration of the postsynaptic density by the HRP enzymatic reaction product. Note the presence of small subsynaptic cisternae (crossed arrow). G, Presence of gold-labeled mRNAs (arrowhead) on a minute cisterna, postsynaptic to a bouton containing pleomorphic vesicles. Scale bars: A–C, 5 μm;D, 1 μm; E, F, 0.5 μm;G, 0.25 μm.