Evolution, immune responses and stress: studies on molluscan cells.

Using a variety of techniques we found the presence of ACTH and opioid-like molecules in the phagocytic spreading hemocytes (SH) and the serum of the mollusc Planorbarius corneus. In vitro experiments have shown that ACTH and beta-endorphin exert chemotactic activity on SH, while ACTH, but not beta-endorphin increases the phagocytic activity of SH. Moreover, ACTH and CRF provoked the release of biogenic amines from the hemocytes, mimicking a proto-stress type of response. Thus, the same mobile cell is capable of immune and proto-stress responses by using as mediators neuropeptides which remained fundamentally similar throughout evolution.