Organization of the olfactory bulb and hypothalamus in wt and Jacob-deficient mice.

(A-C) Microphotographs showing the morphology of the olfactory bulb (BO) of wt (+/+) and Jacob/Nsmf ko (-/-) mice. (A) Nissl stained sections display the general morphology and subregions of the olfactory bulb (Bregma 2.8 mm, 50x magnification, scale bar 500 μm; Gl, stratum glomerulosum; EPl, stratum plexiforme externum, Mi, mitral cell layer, IPl, internal plexiform layer, AON, anterior olfactory nucleus, aci, anterior commissure, intrabulbar part, lo, lateral olfactory tract). (B) shows sections of both genotypes stained against GnRH (50x magnification, scale bar 500 μm). The frames in (B) indicate the image sections shown in (C). In (C) (200x magnification, scale bar 100 μm) the sample fields are marked, which were used to analyze the fiber densities in Gl and EPl. There are no differences in general morphology between wt and Jacob-deficient mice. (D, E) Quantification of GnRH-IR neurons (D) and fiber densities (E) in brains of wt (+/+) and Jacob/Nsmf ko (-/-) mice. (D) The number of GnRH-positive neurons was estimated in the olfactory bulb (Gl, EPl), in the medial septum (MS), ventral diagonal (VDB) and horizontal diagonal band (HDB) of Broca and preoptic area (PA). (E) The density of GnRH-IR fibers was analyzed in the same regions and furthermore in anteroventral paraventricular hypothalamic nucleus (AVPe) and nucleus arcuatus hypothalami (Arc). No significant differences were found between wt and Jacob/Nsmf ko mice (data are reported as mean ± SEM, two-way repeated measures ANOVAs were performed using REGION as within-subject factor and MOUSE LINE as between-subject factor. Post hoc analyses were performed using unpaired t-tests (Welch’s test) with Bonferroni-Holm adjustment). (F-H) Microphotographs showing the distribution of GnRH-IR neurons and fibers in the hypothalamic area of wt and Jacob/Nsmf ko mice. (F) and (G) display the periventricular (Pe) and arcuate hypothalamic nuclei (Arc) around the third ventricle (III) (Bregma -1.70 mm, scale bars are 100 μm). (H) shows exemplary GnRH-IR neurons in the medial preoptic area (PA) of wt and Jacob/Nsmf ko mice (Bregma 0.5 mm, scale bars are 20 μm).