- Cloning and expression of a human P2U nucleotide receptor, a target for cystic fibrosis pharmacotherapy. Parr, C.E., Sullivan, D.M., Paradiso, A.M., Lazarowski, E.R., Burch, L.H., Olsen, J.C., Erb, L., Weisman, G.A., Boucher, R.C., Turner, J.T. Proc. Natl. Acad. Sci. U.S.A. (1994)