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. 2023 Mar 29;90:104535. doi: 10.1016/j.ebiom.2023.104535

Fig. 4.

Fig. 4

AMH induces morphological plasticity in the ME of the adult female brain. (a) Schematic representation summarizing the different steps of the EM experiments. (b–e) Representative electron micrographs of GnRH-immunoreactive axon terminals (immunogold) from hypothalamic explants containing the ME of female rat in diestrus, incubated in the absence (b and c) or the presence (d and e) of AMHC (1 μg/ml) for 30 min. GnRH axonal endings are pseudo-coloured in blue and the pericapillary space (p.s.) in pink. Insets in b and d are high-magnification views of boxes drawn in b and d. Arrowheads in insets point to GnRH-immunoreactive vesicles. (c and e) Photomicrographs were filled with pseudocolors to highlight respectively the GnRH terminals (blue), other neuroendocrine nerve terminals contained in the external layer of the ME (yellow), the pericapillary space (p.s.) in pink and the tanycytic end-feet (green). (f) Quantitative analysis of the percentage of area occupied by tanycytes in the external zone of the ME at 2 μm from the pericapillary space, in explants from rats in diestrus treated or not with AMHC (∗∗∗∗P < 0.0001; Wilcoxon–Mann–Whitney test; n = 5 controls, N = 110 number of analysed EM photomicrographs in controls; n = 3 AMH-treat group, N = 150 number of analysed EM photomicrographs in the AMH-treat group). (g) Quantitative analysis of the percentage of GnRH nerve terminals located at less than 1 μm from the pericapillary space in the external zone of the ME, in explants from rats in diestrus treated or not with AMHC (∗P < 0.05; Wilcoxon–Mann–Whitney test; n = 5 controls, N = 110 number of GnRH-immunoreactive axon terminals measured per explant in controls; n = 3 AMH-treat group, N = 150 number of GnRH-immunoreactive axon terminals measured per explant in the AMH-treat group). The horizontal line in each plot corresponds to the median value. The vertical line represents the 25th–75th percentile range. (h) Schematic representation of the micro-structural changes occurring periodically in the ME during the different phases of the estrous cycle and in diestrous ME explants treated in acute with AMH. Abbreviations: b.l., basal lamina; cap, capillary; EM, electron microscopy; ME, median eminence; n, neurons; p.s., pericapillary space; tan, tanycytes.