- The increased proliferation of cultured neuroblastoma cells treated with vasoactive intestinal peptide is enhanced by simultaneous inhibition of neutral endopeptidase. Wollman, Y., Blumberg, S., Spungin, A., Brenneman, D.E., Fridkin, M., Wollman, J., Iaina, A., Gozes, I. Regul. Pept. (2002)