STATIONARY ORGANOTYPIC CULTURES OF OXYTOCIN AND VASOPRESSIN MAGNOCELLULAR NEURONS FROM RAT AND MOUSE HYPOTHALAMUS

Rat and mouse hypothalami from postnatal animals containing highly dif ferentiated neurones survive very well in long-term (>15 days in vitro , DIV) stationary organotypic cultures. Magnocellular oxytocin (OT) an d vasopressin (VP) neurones are present in identifiable paraventricula r (PVN), supraoptic (SON) and accessory (ACC) nuclei in these cultures . After 15 DIV in standard medium immunocytochemistry revealed 427 +/- 63 OT cells and 217 +/- 27 VP cells per cultured rat hypothalamus, an d 380 +/- 72 OT cells and 622 +/- 91 VP cells per cultured mouse hypot halamus. Following a 7-day adaptation period in standard culture mediu m containing serum, the rat slice-explants survived very well after su bsequent transfer to defined, serum- free media (SFM) for an additiona l 8 days. The number of OT cells surviving in SFM was 612 +/- 147 OT c ells per cultured rat hypothalamus. Only 0.5% of the magnocellular OT and VP neurones in the cultures appeared to express both peptides, Exp eriments on c-fos gene expression in these cultures showed that while only 12% of the magnocellular OT and VP neurones contained barely dete ctable Fos protein in their nuclei under control conditions, potassium depolarization of these cultures for 3 h produced intense c-fos expre ssion in 87-91% of these cells. Thus, magnocellular neurones in these cultures are sufficiently stable and responsive to permit long-term ph ysiological and gene expression studies to be done under defined media conditions.