Cardiovascular activity of Micrurus lemniscatus lemniscatus (South American coralsnake) venom.

Autor: Floriano RS; Graduate Program in Health Sciences, University of Western São Paulo (UNOESTE), Rodovia Raposo Tavares km 572, B2-205, 19067-175, Presidente Prudente, SP, Brazil; Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Rua Tessália Vieira de Camargo, 126, 13083-887, Campinas, SP, Brazil., Torres-Bonilla KA; Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Rua Tessália Vieira de Camargo, 126, 13083-887, Campinas, SP, Brazil., Rojas-Moscoso JA; Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Rua Tessália Vieira de Camargo, 126, 13083-887, Campinas, SP, Brazil., Dias L; Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Rua Tessália Vieira de Camargo, 126, 13083-887, Campinas, SP, Brazil., Rocha T; Multidisciplinar Research Laboratory, São Francisco University (USF), Av. São Francisco de Assis, 218, 12916-900, Bragança Paulista, SP, Brazil., Silva NJ Jr; Graduate Program in Environmental Sciences and Health, School of Medical, Pharmaceutical and Biomedical Sciences, Pontifical Catholic University of Goiás (PUC Goiás), Rua 232, 128, 74605-140, Goiânia, GO, Brazil., Hyslop S; Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Rua Tessália Vieira de Camargo, 126, 13083-887, Campinas, SP, Brazil., Rowan EG; Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161Cathedral Street, G4 0RE, Glasgow, UK. Electronic address: e.g.rowan@strath.ac.uk.
Jazyk: angličtina
Zdroj: Toxicon : official journal of the International Society on Toxinology [Toxicon] 2020 Oct 30; Vol. 186, pp. 58-66. Date of Electronic Publication: 2020 Aug 02.
DOI: 10.1016/j.toxicon.2020.07.019
Abstrakt: Envenomation by coralsnakes (Micrurus spp.) is characterized by blockade of peripheral neurotransmission mediated by the presence of α- and β-neurotoxins. However, little is known about their cardiovascular activity. Micrurus lemniscatus lemniscatus is a coralsnake found in the Amazon basin and occasionally causes envenomation in humans. In this study, we examined the hemodynamic, vascular and atrial responses to M. l. lemniscatus venom. Anesthetized rats were used for hemodynamic and electrocardiogram (ECG) recordings; in vitro experiments were carried out in rat isolated thoracic aorta and atria preparations. In vivo, venom (0.1 and 0.3 mg/kg) caused immediate and persistent hypotension that was maximal within the first minute with both doses being lethal after ~40 and ~20 min, respectively. ECG, heart and respiratory rates were not altered during the transient hypotension phase induced by venom but all altered prior to death. There was no evidence of myonecrosis in cardiac muscle tissue, pulmonary hemorrhage nor thrombosis in anesthetized rats exposed to venom. In vitro, venom (10 μg/ml) did not contract aortic strips nor affected the maximal responses to pre-contraction with phenylephrine (PE, 0.0001-30 μM) in strips with and without endothelium. However, venom (10 μg/ml) relaxed aortic strips with endothelium pre-contracted with PE. In aortic strips pre-contracted with PE, venom prevented acetylcholine (0.0001-30 μM)-induced relaxation in strips with endothelium without affecting relaxation induced by sodium nitroprusside (0.1-100 nM) in strips without endothelium. Venom (30 μg/ml) produced a transient increase of atrial contractile force without affecting atrial rate. Taken together these findings indicate a predominantly vascular action of the venom, most likely involving toxins interacting with muscarinic receptors.
(Copyright © 2020 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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