Slice cultures of rat hypothalamus examined by immunohistochemical staining for neurohypophyseal peptides and GFAP.

Organotypic cultures were prepared from slices of neonatal rat hypothalami and were immunohistochemically stained for the neurohypophyseal peptides vasopressin and oxytocin, their associated neurophysins, and for glial fibrillary acidic protein (GFAP). Both glial and neural elements survived and matured within the cultures, expressing cellular morphologies and retaining a topographic organization similar to that found in vivo. Neurones producing peptides were readily identified and such peptidergic neurones elaborated processes with an appearance characteristic of beaded axons. These presumptive axons grew in a selective and specific manner over certain regions in the slice cultures while avoiding other regions in a manner similar to that found in vivo. In cocultures of hypothalamus and neurointermediate lobe tissue, peptidergic axons found and grew over the neurointermediate lobe tissue and elaborated extensive terminal arborizations. Thus, it appears that at least some of the cues used for appropriate axonal guidance are maintained in these cultures. Organotypic cultures retain many in vivo characteristics as regards cellular morphology and cellular interactions, yet provide an in vitro environment useful for the study of morphology, physiology, cell biology and neurone-target interaction of hypothalamic neurones.