Syntaxin 3 is not expressed at putative conventional glutamatergic synapses. A. Syntaxin 3 labeling is present in numerous terminals in the inner plexiform layer (IPL), corresponding to the ribbon synapse-containing terminals of bipolar cells (see text for details). B. Vesicular glutamate transporter 3 (VGLUT3) is expressed in a putative glutamatergic amacrine cell type and its terminals (arrows) in the mid-IPL. C. There is no colocalization of syntaxin 3- and VGLUT3-positive terminals, although there is some contact between these terminals. Images shown from a projection of 14 optical sections with total thickness of 1.89 μm. INL, inner nuclear layer, GCL, ganglion cell layer. Scale bars = 10 μm.