- Mice lacking the M3 muscarinic acetylcholine receptor are hypophagic and lean. Yamada, M., Miyakawa, T., Duttaroy, A., Yamanaka, A., Moriguchi, T., Makita, R., Ogawa, M., Chou, C.J., Xia, B., Crawley, J.N., Felder, C.C., Deng, C.X., Wess, J. Nature (2001)