CCK-8S increased the filopodia and spines density in cultured hippocampal neurons of APP/PS1 and wild-type mice

Cholecystokinin (CCK), a neuropeptide, is widely distributed in the brain. The function of CCK is involved in many brain functions including learning and memory, but the cellular mechanism is poorly understood. In the present study, we investigated the effect of CCK on dendritic filopodia and spines of cultured hippocampal neurons from wild-type and APP/PS1 mice. The cultured hippocampal neurons were infected with CMV-GFP (CMV promoter with green fluorescent protein) adenovirus 24 h before image acquisition to display the subtle structure of dendrites. Cholecystokinin octapeptide sulfated (CCK-8S, 0.2 μM) was added into the cultured solution from divided in vitro day 2 (DIV 2). A decrease of filopodia and spines density was observed in APP/PS1 mice compared with that of wild type mice. CCK-8S increased the density of filopodia and spines at DIV 7, DIV 14 and DIV 21 in hippocampal neurons of both wild-type and APP/PS1 mice. In addition, this effect was inhibited by CI988, an antagonist of CCK-2 receptor. Those results indicate that CCK-8S can influence the dendritic development and spine genesis of cultured hippocampal neurons derived from both wild-type and APP/PS1 mice. These data suggest that CCK may play an important role in learning and memory.