FMRFamide-like activity in the ganglia and in a single identified neurone of Helix aspersa

Abstract

1. Extracts of cell F1, the largest neurone in the right parietal ganglion, contain FMRFamide-like activity when assayed on the radula protractor muscle of Busycon contrarium. 2. The activity, in terms of FMRFamide equivalents, varied from 1 to 7 pmol/cell. The neurones of recently aestivating snails had about twice the activity of cells from continually nonaestivating animals. 3. The active substance from F1 had a higher R f value (0.83) on thin-layer chromatograms than authentic FMRFamide (0.75). 4. Extracts of pooled ganglia contain FMRFamide-like activity that coelutes with authentic FMRFamide on Sephadex G-15 columns, but that separates from authentic FMRFamide during cation-exchange chromatography. This activity has a slightly higher R f value (0.82) than FMRFamide on cellulose thin-layer chromatograms. 5. The FMRFamide-like factor in the giant cell F1 is probably the same as that found in whole brain extracts. Both substances are peptide analogues of FMRFamide, probably with some modifications at the N-terminal.