1
|
Vuong NT, Jackson TNW, Wright CE. Role of Phospholipases A 2 in Vascular Relaxation and Sympatholytic Effects of Five Australian Brown Snake, Pseudonaja spp., Venoms in Rat Isolated Tissues. Front Pharmacol 2021; 12:754304. [PMID: 34744732 PMCID: PMC8566954 DOI: 10.3389/fphar.2021.754304] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 10/11/2021] [Indexed: 11/13/2022] Open
Abstract
Human envenoming by Australian brown snakes (Pseudonaja spp.) may result in potentially life-threatening hypotension and subsequent cardiovascular collapse. There have been relatively few studies of the cardiovascular and sympathetic effects of Pseudonaja spp. venoms. In this study, we have examined the effects of venom from five brown snake species-P. affinis, aspidorhyncha, inframacula, nuchalis, and textilis-on cardiac inotropic and chronotropic responses, vascular tone, and sympathetic nerve-induced vascular contractions in rat isolated tissues. The role of phospholipases A2 (PLA2s) in venom-induced effects was assessed with the sPLA2 inhibitor varespladib. In rat isolated left and right atria, there were no physiologically relevant effects of Pseudonaja venoms (0.1-30 µg/ml) on left atrial force of contraction (inotropy) or right atrial rate (chronotropy). In contrast, in isolated small mesenteric arteries precontracted with a thromboxane mimetic, each of the five brown snake venoms (at 30 µg/ml) caused marked vasorelaxation (-60 to -90% of contractile tone). Pretreatment with varespladib (1 µM) significantly inhibited the vasorelaxation caused by P. aspidorhyncha, P. nuchalis, and P. textilis venoms. Electrically induced sympathetic nerve-mediated contractions of mesenteric arteries were significantly attenuated by only P. textilis, and P. affinis venoms (30 µg/ml) and these sympatholytic effects were inhibited by varespladib (1 µM). Based on their inhibition with the sPLA2 inhibitor varespladib, we conclude that PLA2 toxins in P. aspidorhyncha, P. nuchalis, and P. textilis venoms are involved in brown snake venom-induced vasorelaxation and the sympatholytic effects of P. affinis, and P. textilis venoms. Our study supports the promising potential role of varespladib as an initial (pre-referral) and/or adjunct (in combination with antivenom) therapeutic agent for brown snake envenoming.
Collapse
Affiliation(s)
- Nhi Thuc Vuong
- Cardiovascular Therapeutics Unit, Department of Biochemistry and Pharmacology, University of Melbourne, Parkville, VIC, Australia
| | - Timothy N W Jackson
- Australian Venom Research Unit, Department of Biochemistry and Pharmacology, University of Melbourne, Parkville, VIC, Australia
| | - Christine E Wright
- Cardiovascular Therapeutics Unit, Department of Biochemistry and Pharmacology, University of Melbourne, Parkville, VIC, Australia
| |
Collapse
|
2
|
Zdenek CN, Llinas J, Dobson J, Allen L, Dunstan N, Sousa LF, Moura da Silva AM, Fry BG. Pets in peril: The relative susceptibility of cats and dogs to procoagulant snake venoms. Comp Biochem Physiol C Toxicol Pharmacol 2020; 236:108769. [PMID: 32376497 DOI: 10.1016/j.cbpc.2020.108769] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 04/07/2020] [Accepted: 04/18/2020] [Indexed: 11/27/2022]
Abstract
Snakebite is a common occurrence for pet cats and dogs worldwide and can be fatal. In Australia the eastern brown snake (Pseudonaja textilis) is responsible for an estimated 76% of reported snakebite cases to domestic pets nationally each year, with the primary pathology being venom-induced consumptive coagulopathy. While only 31% of dogs survive P. textilis bites without antivenom, cats are twice as likely to survive bites (66%). Even with antivenom treatment, cats have a significantly higher survival rate. The reason behind this disparity is unclear. Using a coagulation analyser (Stago STA R Max), we tested the relative procoagulant effects of P. textilis venom-as well as 10 additional procoagulant venoms found around the world-on cat and dog plasma in vitro, as well as on human plasma for comparison. All venoms acted faster upon dog plasma than cat or human, indicating that dogs would likely enter coagulopathic states sooner, and are thus more vulnerable to procoagulant snake venoms. The spontaneous clotting time (recalcified plasma with no venom added) was also substantially faster in dogs than in cats, suggesting that the naturally faster clotting blood of dogs predisposes them to being more vulnerable to procoagulant snake venoms. This is consistent with clinical records showing more rapid onset of symptoms and lethal effects in dogs than cats. Several behavioural differences between cats and dogs are also highly likely to disproportionately negatively affect prognosis in dogs. Thus, compared to cats, dogs require earlier snakebite first-aid and antivenom to prevent the onset of lethal venom effects.
Collapse
Affiliation(s)
- Christina N Zdenek
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia.
| | | | - James Dobson
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Luke Allen
- Venom Supplies Pty Ltd, Stonewell Rd, Tanunda, SA 5352, Australia
| | - Nathan Dunstan
- Venom Supplies Pty Ltd, Stonewell Rd, Tanunda, SA 5352, Australia
| | - Leijiane F Sousa
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia; Laboratório de Imunopatologia, Instituto Butantan, São Paulo 05503-900, Brazil
| | | | - Bryan G Fry
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia.
| |
Collapse
|
3
|
|
4
|
Kakumanu R, Kemp-Harper BK, Silva A, Kuruppu S, Isbister GK, Hodgson WC. An in vivo examination of the differences between rapid cardiovascular collapse and prolonged hypotension induced by snake venom. Sci Rep 2019; 9:20231. [PMID: 31882843 PMCID: PMC6934742 DOI: 10.1038/s41598-019-56643-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 12/16/2019] [Indexed: 11/10/2022] Open
Abstract
We investigated the cardiovascular effects of venoms from seven medically important species of snakes: Australian Eastern Brown snake (Pseudonaja textilis), Sri Lankan Russell’s viper (Daboia russelii), Javanese Russell’s viper (D. siamensis), Gaboon viper (Bitis gabonica), Uracoan rattlesnake (Crotalus vegrandis), Carpet viper (Echis ocellatus) and Puff adder (Bitis arietans), and identified two distinct patterns of effects: i.e. rapid cardiovascular collapse and prolonged hypotension. P. textilis (5 µg/kg, i.v.) and E. ocellatus (50 µg/kg, i.v.) venoms induced rapid (i.e. within 2 min) cardiovascular collapse in anaesthetised rats. P. textilis (20 mg/kg, i.m.) caused collapse within 10 min. D. russelii (100 µg/kg, i.v.) and D. siamensis (100 µg/kg, i.v.) venoms caused ‘prolonged hypotension’, characterised by a persistent decrease in blood pressure with recovery. D. russelii venom (50 mg/kg and 100 mg/kg, i.m.) also caused prolonged hypotension. A priming dose of P. textilis venom (2 µg/kg, i.v.) prevented collapse by E. ocellatus venom (50 µg/kg, i.v.), but had no significant effect on subsequent addition of D. russelii venom (1 mg/kg, i.v). Two priming doses (1 µg/kg, i.v.) of E. ocellatus venom prevented collapse by E. ocellatus venom (50 µg/kg, i.v.). B. gabonica, C. vegrandis and B. arietans (all at 200 µg/kg, i.v.) induced mild transient hypotension. Artificial respiration prevented D. russelii venom induced prolonged hypotension but not rapid cardiovascular collapse from E. ocellatus venom. D. russelii venom (0.001–1 μg/ml) caused concentration-dependent relaxation (EC50 = 82.2 ± 15.3 ng/ml, Rmax = 91 ± 1%) in pre-contracted mesenteric arteries. In contrast, E. ocellatus venom (1 µg/ml) only produced a maximum relaxant effect of 27 ± 14%, suggesting that rapid cardiovascular collapse is unlikely to be due to peripheral vasodilation. The prevention of rapid cardiovascular collapse, by ‘priming’ doses of venom, supports a role for depletable endogenous mediators in this phenomenon.
Collapse
Affiliation(s)
- Rahini Kakumanu
- Monash Venom Group, Department of Pharmacology, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, 3168, Australia
| | - Barbara K Kemp-Harper
- Monash Venom Group, Department of Pharmacology, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, 3168, Australia
| | - Anjana Silva
- Monash Venom Group, Department of Pharmacology, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, 3168, Australia.,Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Saliyapura, 50008, Sri Lanka
| | - Sanjaya Kuruppu
- Department of Biochemistry & Molecular Biology, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, 3168, Australia
| | - Geoffrey K Isbister
- Monash Venom Group, Department of Pharmacology, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, 3168, Australia.,Clinical Toxicology Research Group, University of Newcastle, Callaghan, NSW, 2308, Australia
| | - Wayne C Hodgson
- Monash Venom Group, Department of Pharmacology, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, 3168, Australia.
| |
Collapse
|
5
|
Kumara H, Seneviratne N, Jayaratne DS, Siribaddana S, Isbister GK, Silva A. Severe coagulopathy in Merrem's hump-nosed pit viper (Hypnale hypnale) envenoming unresponsive to fresh frozen plasma: A case report. Toxicon 2019; 163:19-22. [DOI: 10.1016/j.toxicon.2019.03.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 03/11/2019] [Accepted: 03/12/2019] [Indexed: 11/17/2022]
|
6
|
Kakumanu R, Kuruppu S, Rash LD, Isbister GK, Hodgson WC, Kemp-Harper BK. D. russelii Venom Mediates Vasodilatation of Resistance Like Arteries via Activation of K v and K Ca Channels. Toxins (Basel) 2019; 11:E197. [PMID: 30939844 PMCID: PMC6520720 DOI: 10.3390/toxins11040197] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 03/17/2019] [Accepted: 03/28/2019] [Indexed: 11/16/2022] Open
Abstract
Russell's viper (Daboia russelii) venom causes a range of clinical effects in humans. Hypotension is an uncommon but severe complication of Russell's viper envenoming. The mechanism(s) responsible for this effect are unclear. In this study, we examined the cardiovascular effects of Sri Lankan D. russelii venom in anaesthetised rats and in isolated mesenteric arteries. D. russelii venom (100 μg/kg, i.v.) caused a 45 ± 8% decrease in blood pressure within 10 min of administration in anaesthetised (100 μg/kg ketamine/xylazine 10:1 ratio, i.p.) rats. Venom (1 ng/mL⁻1 μg/mL) caused concentration-dependent relaxation (EC50 = 145.4 ± 63.6 ng/mL, Rmax = 92 ± 2%) in U46619 pre-contracted rat small mesenteric arteries mounted in a myograph. Vasorelaxant potency of venom was unchanged in the presence of the nitric oxide synthase inhibitor, L-NAME (100 µM), or removal of the endothelium. In the presence of high K⁺ (30 mM), the vasorelaxant response to venom was abolished. Similarly, blocking voltage-dependent (Kv: 4-aminopryidine; 1000 µM) and Ca2+-activated (KCa: tetraethylammonium (TEA; 1000 µM); SKCa: apamin (0.1 µM); IKCa: TRAM-34 (1 µM); BKCa; iberiotoxin (0.1 µM)) K⁺ channels markedly attenuated venom-induced relaxation. Responses were unchanged in the presence of the ATP-sensitive K⁺ channel blocker glibenclamide (10 µM), or H1 receptor antagonist, mepyramine (0.1 µM). Venom-induced vasorelaxtion was also markedly decreased in the presence of the transient receptor potential cation channel subfamily V member 4 (TRPV4) antagonist, RN-1734 (10 µM). In conclusion, D. russelii-venom-induced hypotension in rodents may be due to activation of Kv and KCa channels, leading to vasorelaxation predominantly via an endothelium-independent mechanism. Further investigation is required to identify the toxin(s) responsible for this effect.
Collapse
Affiliation(s)
- Rahini Kakumanu
- Department of Pharmacology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing & Health Sciences, Monash University, Clayton VIC 3800, Australia.
| | - Sanjaya Kuruppu
- Department of Biochemistry & Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton VIC 3800, Australia.
| | - Lachlan D Rash
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, St Lucia QLD 4072, Australia.
| | - Geoffrey K Isbister
- Clinical Toxicology Research Group, University of Newcastle, Callaghan NSW 2308, Australia.
| | - Wayne C Hodgson
- Department of Pharmacology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing & Health Sciences, Monash University, Clayton VIC 3800, Australia.
| | - Barbara K Kemp-Harper
- Department of Pharmacology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing & Health Sciences, Monash University, Clayton VIC 3800, Australia.
| |
Collapse
|
7
|
Zdenek CN, Hay C, Arbuckle K, Jackson TNW, Bos MHA, Op den Brouw B, Debono J, Allen L, Dunstan N, Morley T, Herrera M, Gutiérrez JM, Williams DJ, Fry BG. Coagulotoxic effects by brown snake (Pseudonaja) and taipan (Oxyuranus) venoms, and the efficacy of a new antivenom. Toxicol In Vitro 2019; 58:97-109. [PMID: 30910521 DOI: 10.1016/j.tiv.2019.03.031] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 03/12/2019] [Accepted: 03/21/2019] [Indexed: 01/03/2023]
Abstract
Snakebite is a neglected tropical disease that disproportionately affects the poor. Antivenom is the only specific and effective treatment for snakebite, but its distribution is severely limited by several factors, including the prohibitive cost of some products. Papua New Guinea (PNG) is a snakebite hotspot but the high costs of Australian antivenoms (thousands of dollars per treatment) makes it unaffordable in PNG. A more economical taipan antivenom has recently been developed at the Instituto Clodomiro Picado (ICP) in Costa Rica for PNG and is currently undergoing clinical trials for the treatment of envenomations by coastal taipans (Oxyuranus scutellatus). In addition to potentially having the capacity to neutralise the effects of envenomations of non-PNG taipans, this antivenom may have the capacity to neutralise coagulotoxins in venom from closely related brown snakes (Pseudonaja spp.) also found in PNG. Consequently, we investigated the cross-reactivity of taipan antivenom across the venoms of all Oxyuranus and Pseudonaja species. In addition, to ascertain differences in venom biochemistry that influence variation in antivenom efficacy, we tested for relative cofactor dependence. We found that the new ICP taipan antivenom exhibited high selectivity for Oxyuranus venoms and only low to moderate cross-reactivity with any Pseudonaja venoms. Consistent with this genus level distinction in antivenom efficacy were fundamental differences in the venom biochemistry. Not only were the Pseudonaja venoms significantly more procoagulant, but they were also much less dependent upon the cofactors calcium and phospholipid. There was a strong correlation between antivenom efficacy, clotting time and cofactor dependence. This study sheds light on the structure-function relationships of the procoagulant toxins within these venoms and may have important clinical implications including for the design of next-generation antivenoms.
Collapse
Affiliation(s)
- Christina N Zdenek
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Chris Hay
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia; Reptile Kingdom Australia, Carrara, QLD, Australia
| | - Kevin Arbuckle
- Department of Biosciences, College of Science, Swansea University, SA2 8PP, United Kingdom
| | - Timothy N W Jackson
- Australian Venom Research Unit, Department of Pharmacology and Therapeutics, University of Melbourne, 3010, VIC, Australia
| | - Mettine H A Bos
- Division of Thrombosis and Hemostasis, Einthoven Laboratory for Vascular and Regenerative Medicine, Leiden University Medical Center, Albinusdreef 2, 2333, ZA, Leiden, the Netherlands
| | - Bianca Op den Brouw
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Jordan Debono
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Luke Allen
- Venom Supplies Pty Ltd, Stonewell Rd, Tanunda, SA 5352, Australia
| | - Nathan Dunstan
- Venom Supplies Pty Ltd, Stonewell Rd, Tanunda, SA 5352, Australia
| | | | - María Herrera
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José 11501-2060, Costa Rica
| | - José M Gutiérrez
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José 11501-2060, Costa Rica
| | - David J Williams
- Australian Venom Research Unit, Department of Pharmacology and Therapeutics, University of Melbourne, 3010, VIC, Australia; Charles Campbell Toxinology Centre, School of Medicine and Health Sciences, University of Papua New Guinea, Boroko 121, National Capital District, Papua New Guinea
| | - Bryan G Fry
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia.
| |
Collapse
|
8
|
Padula A, Leister E. Eastern brown snake ( Pseudonaja textilis ) envenomation in dogs and cats: Clinical signs, coagulation changes, brown snake venom antigen levels and treatment with a novel caprylic acid fractionated bivalent whole IgG equine antivenom. Toxicon 2017; 138:89-97. [DOI: 10.1016/j.toxicon.2017.08.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 08/10/2017] [Accepted: 08/17/2017] [Indexed: 10/19/2022]
|
9
|
Chaisakul J, Rusmili MR, Hodgson WC, Hatthachote P, Suwan K, Inchan A, Chanhome L, Othman I, Chootip K. A Pharmacological Examination of the Cardiovascular Effects of Malayan Krait (Bungarus candidus) Venoms. Toxins (Basel) 2017; 9:E122. [PMID: 28353659 DOI: 10.3390/toxins9040122] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 03/23/2017] [Accepted: 03/24/2017] [Indexed: 11/17/2022] Open
Abstract
Cardiovascular effects (e.g., tachycardia, hypo- and/or hypertension) are often clinical outcomes of snake envenoming. Malayan krait (Bungarus candidus) envenoming has been reported to cause cardiovascular effects that may be related to abnormalities in parasympathetic activity. However, the exact mechanism for this effect has yet to be determined. In the present study, we investigated the in vivo and in vitro cardiovascular effects of B. candidus venoms from Southern (BC-S) and Northeastern (BC-NE) Thailand. SDS-PAGE analysis of venoms showed some differences in the protein profile of the venoms. B. candidus venoms (50 µg/kg-100 µg/kg, i.v.) caused dose-dependent hypotension in anaesthetised rats. The highest dose caused sudden hypotension (phase I) followed by a return of mean arterial pressure to baseline levels and a decrease in heart rate with transient hypertension (phase II) prior to a small decrease in blood pressure (phase III). Prior administration of monovalent antivenom significantly attenuated the hypotension induced by venoms (100 µg/kg, i.v.). The sudden hypotensive effect of BC-NE venom was abolished by prior administration of hexamethonium (10 mg/kg, i.v.) or atropine (5 mg/kg, i.v.). BC-S and BC-NE venoms (0.1 µg/kg-100 µg/ml) induced concentration-dependent relaxation (EC50 = 8 ± 1 and 13 ± 3 µg/mL, respectively) in endothelium-intact aorta. The concentration-response curves were markedly shifted to the right by pre-incubation with L-NAME (0.2 mM), or removal of the endothelium, suggesting that endothelium-derived nitric oxide (NO) is likely to be responsible for venom-induced aortic relaxation. Our data indicate that the cardiovascular effects caused by B. candidus venoms may be due to a combination of vascular mediators (i.e., NO) and autonomic adaptation via nicotinic and muscarinic acetylcholine receptors.
Collapse
|
10
|
Chaisakul J, Isbister GK, O'Leary MA, Parkington HC, Smith AI, Hodgson WC, Kuruppu S. Prothrombin activator-like toxin appears to mediate cardiovascular collapse following envenoming by Pseudonaja textilis. Toxicon 2015; 102:48-54. [PMID: 25959508 DOI: 10.1016/j.toxicon.2015.05.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 05/04/2015] [Accepted: 05/06/2015] [Indexed: 11/16/2022]
Abstract
Brown snake (Pseudonaja spp.)-induced early cardiovascular collapse is a life-threatening medical emergency in Australia. We have previously shown that this effect can be mimicked in animals and is mediated via the release of endogenous mediators. In the present study, we aimed to purify and characterize the component in Pseudonaja textilis venom which induces cardiovascular collapse following envenoming. The component (fraction 3) was isolated using a combination of techniques including hydroxyapatite and reverse phase chromatography. Fraction 3 (10 or 20 μg/kg, i.v.) produced a rapid decrease in mean arterial pressure (MAP) followed by cardiovascular collapse. Fraction 3-induced early collapse was abolished by prior administration of smaller priming doses of fraction 3 (i.e. 2 and 5 μg/kg, i.v.) or heparin (300 units/kg, i.v.). P. textilis whole venom (1 and 3 μg/ml), but not fraction 3 (1 or 3 μg/ml), induced endothelium-dependent relaxation in isolated rat mesenteric arteries. SDS-PAGE gel indicated the presence of 9-10 protein bands of fraction 3. Using proteomic based analysis some protein bands of fraction 3 were identified as subunits of venom prothrombin activator, pseutarin C of P. textilis venom. Our results conclude that prothrombin activator-like toxin is likely to be a contributor to the rapid collapse induced by P. textilis venom.
Collapse
Affiliation(s)
- Janeyuth Chaisakul
- Monash Venom Group, Department of Pharmacology, Monash University, VIC, 3800, Australia; Department of Pharmacology, Phramongkutklao College of Medicine, Bangkok, 10400, Thailand
| | - Geoffrey K Isbister
- Monash Venom Group, Department of Pharmacology, Monash University, VIC, 3800, Australia; Department of Clinical Pharmacology and Toxicology, Calvary Mater, NSW, 2298, Australia
| | - Margaret A O'Leary
- Department of Clinical Pharmacology and Toxicology, Calvary Mater, NSW, 2298, Australia
| | | | - A Ian Smith
- Department of Biochemistry and Molecular Biology, Monash University, VIC, 3800, Australia
| | - Wayne C Hodgson
- Monash Venom Group, Department of Pharmacology, Monash University, VIC, 3800, Australia
| | - Sanjaya Kuruppu
- Department of Biochemistry and Molecular Biology, Monash University, VIC, 3800, Australia.
| |
Collapse
|