Fig. 5

RTE-2_OV immunostaining in different areas of the brain. Coronal sections of the supra-esophageal (SEM; a–d) and sub-esophageal (SUB; e–h) masses and horizontal sections for the optic lobe (OL; i–l) following fluorescent-IHC (RTE-2_OV signal in green, DAPI used as a nuclear stain in magenta) highlight a differential pattern of positive cells and fibers in O. vulgaris brain. A schematic drawing of the brain parts is provided with areas of interest indicated in the green square. a Large positive cells are found in the vertical lobe (VL). These appear organized in trunks and clearly distinguishable from the population of numerous amacrine cells constituting the VL (DAPI stained layer). b Large cells in the sub-vertical lobe (cellular wall) and a part of the bundle of fibers are present at the beginning of the sub-frontal lobe (c). d Scattered positive cells are also identified in the posterior buccal lobe. Several positive cells are identified in the SUB in the cellular walls of the vasomotor lobe (e) and in discrete areas of the pedal lobe (f). A similar pattern of positive cells is recognized at the level of the anterior part of the pedal lobe (g). A detail in the higher magnification (h; square in g) of the cellular layer of the lobe serves to highlight the population of positive cells. In the OL, several amacrine cells are found positive in the external granular layer (i). The OL-medulla is populated by few immune-reactive neurons found in the cellular islands (j, k), and positive fibers dispersed in the surrounding neuropil (j, k). Positive cells and fibers are also identified in the peduncle lobe. The internal layer of cells of the neural wall of the olfactory lobe and the spine (l) are shown. Scale bars, 100 μm, with the exception of a and h (50 μm)