Neutral endopeptidase-24.11 (NEP)-like activity in molluscan hemocytes

Using a spectrofluorimetric procedure, we found that the plasma membrane from hemocytes of two freshwater snails, Planorbarius corneus and Viviparus ater, shows neutral endopeptidase-24.11 (NEP)-like activity. Moreover, the addition of ACTH(1-24) to the hemolymph provokes an increase in NEP-like activity. This increased NEP-like activity is blocked by phosphoramidon, a potent inhibitor of mammalian NEP. These findings suggest that this peptidase has been well conserved in the course of evolution and plays an important role in immune-neuroendocrine mechanisms.