Histaminolytic Agents in a Crude Venom Extract from the Sea Anemone Bunodosoma cavernata

A crude extract from the sea anemone Bunodosoma cavernata antoganized histamine-induced contractions of the ileum in a dose-related fashion and shifted the histamine dose-response curve to the right. Doubling the dose of histamine failed to surmount the antagonism. Similar results were obtained when ACh was used as the agonist. While the extract appeared to have no effect on 5-HT-induced contractions, it potentiated KCl-induced contraction of the ileum. Therefore, we suggest that the crude extract from B. cavernata contains histaminolytic agent(s) which inhibited histamine-induced contractions of the ileum. The action of the extract was probably non-selective since ACh-induced contractions were similarly inhibited. Furthermore, the histamine antagonism was probably of a non-competitive type since it was not surmounted by doubling the concentration of histamine. Finally, that the extract failed to inhibit 5-HT- and KCl-induced contractions appear to exclude a general toxic or local anaesthetic action on the tissue, and a receptor action is favoured.