Isolation of bioactive compounds from Helix aspersa nerve tissue and the effect of pQPPLPRYamide on heart, esophagus and central neurons of H. aspersa and rectum of Anodonta woodiana.

1. Both acetone and methanol extraction was used to isolate bioactive compounds from 1000 Helix aspersa brains. 2. Seven compounds were isolated of which four were identified as follows: Ha-1, 5-hydroxytryptamine; Ha-3, GSPYFVamide; Ha-4, pQPPLPRYamide; Ha-5, SGYLAFPRMamide. There was insufficient material to identify Ha-2, Ha-6 and Ha-7. 3. Ha-4, pQPPLPRYamide, was found to excite the heart of H. aspersa, relax the esophagus and both excite (mainly) and inhibit central neurons. In addition, this peptide contracted the rectum of Anodonta woodiana. 4. It is concluded that pQPPLPRYamide is an example of a new molluscan peptide family, designated as PRYamide.