TOBET, SA; WALKER, HJ; SENEY, ML; The Shriver Center at UMMS; The Shriver Center at UMMS; The Shriver Center at UMMS: Viewing cell movements in the developing neuroendocrine brain

Many studies suggest that migratory guidance cues within the developing brain are diverse across many regions. To better understand the early development and differentiation of select brain regions; an in vitro method was developed using selected strains of embryonic mice. In particular, organotypic slices are used to test factors that influence the development of brain nuclei or layers. 250�m thick slices cut on a vibrating microtome are prepared and maintained in vitro for 0-3 days. Nissl stain analyses often show a uniform distribution of cells in the regions of interest on the day of plating (embryonic days 12-15). After 3 days in vitro, cellular aggregation suggesting nuclear or layer formation has occurred in several regions. Nuclear or layer formation in vitro suggests that key factors reside locally within the plane of the slices. Video microscopy studies are used to follow the migration of fluorescently-labeled cells in brain slices from mice maintained in serum-free media for 1 to 3 days. Transgenic mice with selective promoter driven expression of fluorescent proteins allows us to view specific cell types (e.g., neurons expressing gonadotropin releasing hormone). The accessibility of an in vitro system that provides for relatively normal brain development over key brief windows of time allows for the significant testing of important mechanisms.