The in vitro vascular effects of two chirodropid (Chironex fleckeri and Chiropsella bronzie) venoms.
Clinical observations suggest a primary cardiotoxic role in fatal Chironex fleckeri stings. The limited research available indicates that Chiropsella bronzie venom acts in a similar manner although appears to be less potent. The aim of the present study was to elucidate the vascular effects of C. fleckeri and C. bronzie venoms using rat isolated aorta. Both venoms produced a sustained contraction of endothelium-denuded aorta which was not significantly affected by prazosin or box jellyfish antivenom. Felodipine significantly reduced the contractile response to C. fleckeri venom but not C. bronzie venom. Both venoms produced an initial relaxation (Phase 1), followed by a sustained contraction (Phase 2), in pre-contracted endothelium-intact aorta. Removal of the endothelium significantly inhibited both phases of the response. NOLA significantly inhibited Phase 1, but not Phase 2, of the response to both venoms. Atropine, HOE 140 or BQ 123 did not have any significant inhibitory effect on either phase. In conclusion, neither C. fleckeri nor C. bronzie venoms appear to contain components with activity at alpha(1)-adrenoceptors. Antivenom was ineffective in reversing the effects of the venom suggesting it is incapable of completely neutralising nematocyst-derived venom. Determining the mechanism of action of these venoms will allow for the development of better treatment strategies.
Winter
Kelly L
KL
Monash Venom Group, Department of Pharmacology, Monash University, Victoria, Australia.
Fernando
Ross
R
Ramasamy
Sharmaine
S
Seymour
Jamie E
JE
Isbister
Geoffrey K
GK
Hodgson
Wayne C
WC
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D000997:Antivenins / Q000494:pharmacology; D001011:Aorta / Q000187:drug effects* / Q000502:physiology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D003064:Cnidarian Venoms / Q000633:toxicity*; D037462:Cubozoa; D004730:Endothelium, Vascular / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015736:Felodipine / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D019335:Nitroarginine / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014661:Vasoconstriction / Q000187:drug effects
D000317:Adrenergic alpha-Antagonists; D000997:Antivenins; D002121:Calcium Channel Blockers; D003064:Cnidarian Venoms; D004791:Enzyme Inhibitors; D019335:Nitroarginine; D015736:Felodipine; D011224:Prazosin