Figure 3.
CCK-receptors (CCK-1R, CCK-2R) are expressed on OE and VNO, whereas CCK-1R is expressed by GnRH-1 neurons in nasal regions. A–I, Sagittal sections of E12.5 mouse immunostained with indicated antibodies. GnRH-1 cells migrate in association with olfactory axons. A–C, GnRH-1 (blue) and NCAM (brown; A, B) or GnRH-1 and peripherin (brown; C). Note that these sections have been counterstained with methyl green. B, High magnification of boxed area in A shows GnRH-1-positive neurons migrating out of the developing VNO along NCAM-immunoreactive axons (arrows). C, Picture similar to that in B, showing GnRH-1 neurons associated with peripherin-positive vomeronasal axons (arrows). D, CCK-2R-immunoreactive fibers (red) colocalized with NCAM-immunopositive olfactory axons (green) crossing the nasalmesenchyme (arrows). The labeling pattern resembles those described in B and C. E, F, Double-label immunofluorescence for CCK-2R (red) and GnRH-1 (green). OE, VNO, and axons extending toward the telecephalon are CCK-2R positive (E; arrows indicate olfactory axons emerging from VNO). GnRH-1 neurons were CCK-2R negative (F, inset). G–I, Double-label immunofluorescence for CCK-1R (red) and GnRH-1 (green). CCK-1R immuno reactivity was detected in the OE, VNO, along olfactory fibers (arrows), and in CCK-1R-positive cells spanning the nasal mesenchyme. CCK-1R-immunoreactive cells coexpressed GnRH-1 (I, inset, arrowheads). Scale bars: A, 245 μm; B, C, 70 μm; D, E, G–I, 34 μm; inset in D, F, 20 μm; inset in F, inset in I, 10 μm.