New observations on the development of the gonadotropin-releasing hormone system in the mouse

✍ Scribed by Wu, T. J. ;Gibson, M. J. ;Rogers, M. C. ;Silverman, A. J.

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 493 KB
• Volume: 33
• Category: Article
• ISSN: 0022-3034
• DOI: 10.1002/(sici)1097-4695(199712)33:7<983::aid-neu9>3.0.co;2-4

✦ Synopsis

In ongoing efforts to study the onnervous system (CNS) and the nasal region. Hence, togeny of gonadotropin-releasing hormone (GnRH) the population of GnRH neurons during early develneurons, we serendipitously observed that increasing opment is much larger than previously appreciated; times of incubation in antibodies enhanced signal demechanisms for its decline are discussed. Neuritic extection. Here, we describe significant differences in tensions on the earliest GnRH neurons are short (30the early migration pattern, population dynamics, and 50 mm) and blunt and may represent the leading edge growth cone morphology from published reports. The of the moving cell. By E12.75, GnRH axons in the first immunoreactive GnRH cells were detected in the CNS had a ribboned or beaded morphology and inmouse at E10.75 (7.6 { 2.8 cells; morning after mating creasingly more complex growth cones were noted Å E0.5), prior to the closure of the olfactory placode. from this time until the day of birth. The most com-Although half of these cells were in the medial wall of plex growth cones were associated with apparent the olfactory pit, the other half had already initiated choice points along the axons' trajectory. By E13.75, their migration, and approximately one quarter had GnRH axons were seen at the presumptive median reached the telencephalic vesicle. Although the migraeminence in all animals, and it was at this stage that tory pattern of the GnRH cells after E11.00 was identithe axons began to branch profusely. Branching, as cal to that described previously, these earliest migratwell as the presence of growth cones, continued posting cells traveled singly rather than in cords, with natally. These results provide further insights into some reaching the presumptive preoptic area (postethe pathfinding mechanisms of GnRH cells and axons. rior to the ganglionic eminence) by E11.75. The num-