Toxicon : official journal of the International Society on Toxinology
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It has been demonstrated that spontaneous nociceptive behaviors, cutaneous hyperalgesia and paw edema can be induced by intraplantar injection of scorpion Buthus martensi Karch (BmK) venom in rats. In the present study, activation of spinal extracellular signal-regulated kinase (ERK) signaling pathway and its contribution to pain-related responses induced by scorpion BmK venom were investigated. It was found that ERK was activated not only in the superficial layers but also in deep layers of L4-L5 spinal cord dorsal horn, which started at 2 min, peaked at 30-60 min and almost disappeared at 4h following intraplantar injection of BmK venom. ⋯ In addition, BmK venom-induced spinal c-Fos expression could be inhibited by U0126 dose-dependently. Intrathecal delivery of NMDA receptor antagonist (5R, 10S)-(+)-5-methyl-10, 11-dihydro-5H-dibenzo [a,d]-cyclohepten-5-10-imine hydrogen maleate (MK-801) and the non-NMDA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) could partially inhibit activation of spinal ERK induced by BmK venom at 30 min. Thus, activation of ERK in spinal cord dorsal horn, partially mediated by NMDA and non-NMDA receptor, potentially contributes to BmK venom-induced pain-related behaviors.
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Many plant and animal toxins cause aversive behaviors in animals due to their pungent or unpleasant taste or because they cause other unpleasant senstations like pain. This article reviews the current state of knowledge of toxins that act at the TRPV1 ion channel, which is expressed in primary sensory neurons, is activated by multiple painful stimuli and is thought to be a key pain sensor and integrator. ⋯ Where possible, structural information about sites of interaction is considered in relation to toxin-binding sites on the Kv ion channel, for which more structural information exists. We discuss a developing model where toxin agonists such as resiniferatoxin and vanillotoxins are proposed to interact with a region of TRPV1 that is homologous to the "voltage sensor" in the Kv1.2 ion channel, to open the channel and activate primary sensory nerves, causing pain.
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Elapid snakes throughout the world are considered very lethal, containing neurotoxic venoms that affect the nervous system. When humans are envenomated it is considered a serious medical emergency, and antivenom is the main form of treatment considered, in spite of the fact that some patients may only survive under intensive therapy treatment such as respiratory support. Coral snakes are part of the family Elapidae and envenomations by these snakes are very low (<2% of total snakebites) in most countries from southeastern United States to Argentina. ⋯ Additionally, venom comparisons were determined through a non-reduced SDS-PAGE for M.f.fulvius, M.t.tener and the Mexican coral snake venom, Micrurus nigrocinctus nigrocinctus. Coralmyn antivenom was able to effectively neutralize three LD(50) doses of all venom from both M.t.tener and M.f.fulvius, while Wyeth antivenom only neutralized M.f.fulvius venom and was not effective in neutralizing three LD(50) doses of M.t.tener venom. Coralmyn is effective in the neutralization of both clinically important coral snake venoms in the US.
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The aim of this retrospective descriptive study was to describe the epidemiological and some common clinical symptoms and signs among humans stung by Hemiscorpius lepturus (H. lepturus) in the southwest province of Iran, Khuzestan. Cases were collected from hospital patients' files referred to two major Khuzestan hospitals over 5 years. Only definite stings of this species, identified by trained health-caring personnel, were included in this study. ⋯ The local symptoms ranged from erythema to severe necrosis with no immediate sensation of pain. Renal toxicity is one of the serious systemic effects, which, if not treated early by administration of the polyvalent antivenom, can progress to severe renal and cardio-respiratory failure. Overall, the findings demonstrate that the characteristic clinical features of envenomation produced by this scorpion differ significantly from those reported for other scorpions in the world.
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To examine antivenom use, premedication, early adverse reactions and patient outcomes after snake bite in rural Papua New Guinea. ⋯ Polyvalent antivenom is the main treatment for envenomation in rural health centres, and early adverse reactions are common. Adrenaline premedication appears to significantly reduce acute adverse reaction rates. Premedication with promethazine and/or hydrocortisone without adrenaline did not reduce early adverse reactions.