Localization of cholecystokinin-octapeptide-like-immunoreactivity in neurons cultured from rat cerebral cortex

Cholecystokinin-octapeptide-like-immunoreactivity (CCK-8-LI) is demonstrable by the indirect immunofluorescent technique in cerebral cortical neurons cultured from fetal rats. Prominent and widespread staining is seen in widely ramifying cellular processes throughout the cultures. Staining in neuronal cell bodies is enhanced by treatment of the cultures with colchicine prior to fixation and can be seen to extend from the perikaryal region into dendrites and axonal processes. While several morphological types of neurons contain CCK-8-LI, there is a relative preponderance of small and moderate-sized bipolar and, to a lesser extent, multipolar neurons. These findings are in concordance with the findings of several investigators in studies of brain sections. The further finding of frequent groupings of CCK-8 neurons is noted and discussed.