Figure 3.

Altered morphology and distribution of GnRH neurons in p75NGFRmutant (-/-) embryos. At E16.5, the majority of GnRH neurons have migrated into the forebrain associated with a subpopulation of olfactory axons. (A) Camera lucida of E16.5 sagittal head showing nasal forebrain junction (red asterisk) and location of anterior commissure (ac) and optic tract (OT) that were used as markers, from which a diagonal line was drawn separating rostral from caudal GnRH cell population. GnRH cells were found in the nasal area [between the VNO (black asterisk) and nasal forebrain junction (NFJ, red asterisk)], at the NFJ, and within the forebrain (black dots). (B) Histogram showing distribution of GnRH cells in the nasal and brain regions at E16.5, a decrease in the number of GnRH cells in the NFJ with a corresponding increase in the caudal cell population is observed in -/- mice. (C) Camera lucida of adult brain showing location of markers for rostral = before anterior commissure (ac), medial = between ac and before suporaoptic nucleus, Blue dots = location of GnRH cells, and caudal = from supraoptic nucleus to caudal brain areas. (D) In the adult, a decrease in the GnRH population within the rostral brain region with corresponding increase in caudal brain was observed. Measurements of GnRH cell diameter (E), perimeter (F) and area (G) revealed a significant reduction in all three parameters in p75NGFR^−/−embryos. ^*p < 0.001.