- PACAP and VIP promote initiation of electrophysiological activity in differentiating embryonic stem cells. Chafai, M., Louiset, E., Basille, M., Cazillis, M., Vaudry, D., Rostène, W., Gressens, P., Vaudry, H., Gonzalez, B.J. Ann. N. Y. Acad. Sci. (2006)