GALANIN AND CHOLECYSTOKININ IN CULTURED MAGNOCELLULAR NEURONS ISOLATED FROM ADULT-RAT SUPRAOPTIC NUCLEI - A CORRELATIVE LIGHT AND SCANNING ELECTRON-MICROSCOPIC STUDY

Cultured magnocellular neurons, isolated from adult rat supraoptic nuc lei, were characterized by immunocytochemistry, using the avidin-bioti n-peroxidase complex and antisera to vasopressin, oxytocin, galanin an d cholecystokinin. Light microscope examination of the immunostained c ultures revealed the presence of vasopressin- and oxytocin-like immuno reactivity, as well as neurons containing either galanin-or cholecysto kinin-like immunoreactivity. In contrast, no significant galanin- or c holecystokinin-like immunoreactivity could be observed in freshly disp ersed cells. Correlative scanning electron microscopical observations in the secondary electron imaging mode revealed that the stained neuro ns appeared significantly brighter than the unstained structures. Comp lementary observations with toad brain sections (preoptic area), immun ostained for galanin, led to the same result. Considering previous res ults, it is suggested that the presence of galanin-and cholecystokinin -like immunoreactivity in the cultured neurons and its virtual absence in freshly dispersed cells is indicating a participation of these pep tides in the regenerative processes taking place during culture. It is further concluded that the avidin-biotin-peroxidase method is suitabl e for correlative light and scanning electron microscopical studies of smooth surfaces and cultured cells.