Autonomic neurons innervate pancreatic islets of Langerhans and maintain blood glucose homeostasis by regulating hormone levels. We previously showed that cell adhesion molecule 1 (CADM1) mediated the attachment and interaction between nerves and aggregated pancreatic islet alpha cells. In this study, we cocultured alpha TC6 cells, a murine alpha cell line, with mouse superior cervical ganglion (SCG) neurons. The oscillation of intracellular Ca2+ concentration ([Ca2+](i)) was observed in 27% and 14% of alpha TC6 and CADM1-knockdown alpha TC6 cells (alpha TC6(siRNA-CADM1) cells) in aggregates, respectively, within 1 min after specific SCG nerve stimulation with scorpion venom. In alpha TC6(siRNA-CADM1) cells, the responding rate during 3 min after SCG nerve stimulation significantly increased compared with that within 1 min, whereas the increase in the responding rate was not significantly different in alpha TC6 cells. This indicated that the response. of alpha TC6 cells according to nerve stimulation occurred more rapidly and effectively than that of alpha TC6(siRNA-CADM1) cells, suggesting CADM1 involvement in promoting the interaction between nerves and alpha cells and among alpha cells. In addition, because we found that neurokinin (NK)-1 receptors, which are neuropeptide substance P receptors, were expressed to a similar extent by both cells, we investigated the effect of substance P on nerve-alpha cell interaction. Pretreatment with CP99,994 (0.1 mu g/ml), an NK-1 receptor antagonist, reduced the responding rate of both cells, suggesting that substance P released from stimulated neurites was a mediator to activate alpha TC6 cells. In addition, alpha cells that were attached to neurites in a CADM1-mediated manner appeared to respond effectively to neurite activation via substance P/NK-1 receptors. (C) 2013 Elsevier Inc. All rights reserved.