An investigation of the biological activity of bullrout (Notesthes robusta) venom.

Bullrout envenomation is known to cause intense pain. Crude bullrout venom and venom fractions were assessed for protease, hyaluronidase, phospholipase and hemolytic activities, reactivity with stonefish antivenom, lethality to brine shrimp and ability to elicit pain in human subjects. Compared with venom obtained from frozen specimens, live fish venom-milking techniques rendered greater venom potency and improved storage characteristics. Although mild proteolytic and hemolytic activity was observed, crude venom demonstrated no hyaluronidase or phospholipase A2 activity, did not affect brine shrimp, or show antigenicity with stonefish antivenom. A single venom protein isolated from bullrout venom is attributed with causing pain in human subjects. The sensations elicited by this novel algesic protein are consistent with chemical stimulation of polymodal nociceptors.