Biological activities of ganglion extracts from a prosobranch mollusc, Fusinus ferrugineus.

Acetone extract of the ganglia of Fusinus ferrugineus was applied to C-18 cartridges, and the flowthrough and retained materials were bioassayed on the radula retractor muscle of the animal. The flowthrough was found to have a potent contractile action and the retained material a potent contraction-inhibiting action in addition to a weak contractile action. The retained material was then applied to a column (2.6 x 40 cm) of Sephadex G-15. Fractions of 4 ml each were collected, and their activities were assayed on twitch contractions of the radula retractor. Three peaks (E1, E2 and E3) of contraction-potentiating activity and one peak (I) of contraction-inhibiting activity were obtained. The maximum activities of peaks E1, E2 and E3 were found at fractions 22, 44 and 50, respectively. The maximum activity of peak I was found at fractions 28-30. All of the activities of these peaks were destroyed by incubating the fractions with the peptidase subtilisin, suggesting that the active substances in the peaks are peptides. Using some kinds of molluscan muscles, the actions of the substances were examined in greater detail. The results suggest that peak E1 may contain a novel excitatory peptide whose molecular weight is more than 1,000, and that peaks E2 and E3 may contain FMRFamide-related peptides. It is also suggested that peak I may contain two or more myomodulin-CARP-related inhibitory peptides.