Novel Neuroexcitatory peptides in injected venom of the fish-hunting cone snail, Conus catus

Abstract

Fish-hunting cone snails ( Conus catus ) from the Indo-pacific region contain venom that have great pharmacological potential. The venom injected by one C. catus can have a unique composition when compared to another, therefore each snail is identified and venom samples are analyzed individually. The venom from C. catus exhibits excitatory or blocking activity depending on the individual. I focused on one C. catus individual and tested the injected venom using two types of neuromuscular preparations. In one preparation, a muscle with an intact nerve was stimulated with a suction electrode and a focal electrode recorded the extracellular muscle action potentials before and after the addition of the venom to the chamber. The venom contained excitatory activity that induced tetanus and the frequency of repetitive action potentials showed a negative trend from the first stimulation at 120 Hz and decreased ten stimulations later (20 sec/stim) to 20 Hz. In another preparation two chambers separated the connected nerve from the muscle and the venom was diluted into the chamber containing the nerve, resulting in muscle tetanus. The results provide evidence suggesting that the venom targets the nerve, not specifically the muscle. The results from the preliminary experiments of this C. catus individual have now been compared to another C. catus whose venom contains a novel neuroexcitatory peptide and exhibits similar tetanus action potential patterns and time course. This physiological comparison of the venom from C. catus individuals indicates there is common neuroexcitatory peptide.