title: An examination of cardiovascular collapse induced by eastern brown snake (Pseudonaja textilis) venom.
abstract: The Pseudonaja genus (Brown snakes) is widely distributed across Australia and bites account for significant mortality. Venom-induced consumption coagulopathy (VICC) and, less often, early cardiovascular collapse occur following envenoming by these snakes. We have previously examined possible mechanism(s) behind the early cardiovascular collapse following Papuan taipan (Oxyuranus scutellatus) envenoming. In the present study, we investigate early cardiovascular collapse in anaesthetized rats following administration of eastern brown snake (Pseudonaja textilis) venom, and prevention of this effect with prior administration of 'priming' doses (i.e. doses of venom which caused a transient hypotensive response) of venom. P. textilis venom (5-10 μg/kg, i.v.) induced cardiovascular collapse in anaesthetized rats, characterized by a rapid decrease in systolic blood pressure until non recordable. Prior administration of 'priming' doses of P. textilis venom (2 and 3 μg/kg) or, at least, 4-5 doses of O. scutellatus (2 μg/kg, i.v.) or Daboia russelii limitis (20 μg/kg, i.v.) venoms prevented cardiovascular collapse induced by P. textilis venom. Moreover, early collapse was also inhibited by prior administration of 2 discrete doses of Acanthophis rugosus venom. Prior administration of commercial polyvalent snake antivenom (500-3000 units/kg, i.v.) or heparin (300 units/kg, i.v.) also inhibited P. textilis venom-induced cardiovascular collapse. Our results indicate that P. textilis venom-induced cardiovascular collapse can be prevented by prior administration of sub-lethal doses of venom from P. textilis, O. scutellatus, A. rugosus and D. russelii limitis. This suggests that sudden cardiovascular collapse following envenoming is likely to involve a common mechanism/pathway activated by different snake venoms.
authors.affiliation: Monash Venom Group, Department of Pharmacology, Monash University, Victoria, Australia.
authors.forename: Janeyuth
authors.initials: J
authors.lastname: Chaisakul
authors.forename: Geoffrey K
authors.initials: GK
authors.lastname: Isbister
authors.forename: Sanjaya
authors.initials: S
authors.lastname: Kuruppu
authors.forename: Nicki
authors.initials: N
authors.lastname: Konstantakopoulos
authors.forename: Wayne C
authors.initials: WC
authors.lastname: Hodgson
mesh_terms: D000818:Animals; D000997:Antivenins / Q000494:pharmacology*; D001315:Australia; D002319:Cardiovascular System / Q000187:drug effects*; D004546:Elapid Venoms / Q000037:antagonists & inhibitors / Q000633:toxicity*; D017815:Elapidae; D006339:Heart Rate / Q000187:drug effects; D007022:Hypotension / Q000139:chemically induced* / Q000517:prevention & control / Q000628:therapy; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D000997:Antivenins; D004546:Elapid Venoms
keywords: ANOVA; Anaesthetized rat; Antivenom; Brown snake; Cardiovascular collapse; HRP; MAP; PVDF; TBST; Tris-buffered saline and Tween 20.; Venom; analysis of variance; horseradish peroxidase; i.p.; i.v.; intraperitoneal administration; intravenous administration; mean arterial pressure; polyvinylidene difluoride