| Full text | |
| Author(s): Show less - |
Couceiro, Fernanda Y. G. M.
;
Demico, Poliana J.
;
Dias, Samuel R.
;
Oliveira, Isabele N.
;
Pacagnelli, Francis L.
;
Silva, Elisangela O.
;
Sant'Anna, Savio S.
;
Grego, Kathleen F.
;
Morais-Zani, Karen
;
Torres-Bonilla, Kristian A.
;
Hyslop, Stephen
;
Floriano, Rafael S.
Total Authors: 12
|
| Document type: | Journal article |
| Source: | Toxicon; v. 234, p. 8-pg., 2023-10-01. |
| Abstract | |
In this work, we examined the neuromuscular blockade caused by venoms from four South-American coralsnakes (Micrurus altirostris - MA, M. corallinus - MC, M. spixii - MS, and M. dumerilii carinicauda - MDC) and the ability of varespladib (VPL), a phospholipase A2 (PLA2) inhibitor, to attenuate this blockade. PLA2 activity was determined using a colorimetric assay and a fixed amount of venom (10 mu g). Neurotoxicity was assayed using a single concentration of venom (10 mu g/ml) in mouse phrenic nerve-diaphragm (PND) preparations mounted for myographic recordings and then subjected to histological analysis. All venoms showed PLA2 activity, with MS and MA venoms having the highest (15.53 +/- 1.9 A425 nm/min) and lowest (0.23 +/- 0.14 A425 nm/min) activities, respectively. VPL (292 and 438 mu M) inhibited the PLA2 activity of all venoms, although that of MA venom was least affected. All venoms caused neuromuscular blockade, with MS and MDC venoms causing the fastest and slowest 100% blockade [in 40 +/- 3 min and 120 +/- 6 min (n = 4), respectively]; MA and MC produced complete blockade within 90-100 min. Preincubation of venoms with 292 mu M VPL attenuated the blockade to varying degrees: the greatest inhibition was seen with MDC venom and blockade by MS venom was unaffected by this inhibitor. These results indicate that PLA2 has a variable contribution to coralsnake venom-induced neuromuscular blockade in vitro, with the insensitivity of MS venom to VPL suggesting that blockade by this venom is mediated predominantly by post-synaptically-active alpha-neurotoxins. (AU) | |
| FAPESP's process: | 20/04287-6 - Structural and pharmacological characterization of toxins isolated from Bothrops bilineatus smaragdinus (forest viper) venom with potential modulatory activity of the motor synaptic release and cardiovascular functions |
| Grantee: | Rafael Stuani Floriano |
| Support Opportunities: | BIOTA-FAPESP Program - Regular Research Grants |
| FAPESP's process: | 20/07268-2 - Characterization of the coagulotoxic profile of venoms of Viperidae snakes with medical importance in Brazil |
| Grantee: | Karen de Morais Zani |
| Support Opportunities: | Regular Research Grants |
| FAPESP's process: | 23/01961-6 - Antagonistic action of marimastat, a metalloprotease synthetic peptide inhibitor, on the myotoxic, hemorrhagic and coagulant effects of Lachesis muta muta (South American Bushmaster) venom in rodents |
| Grantee: | Isabele Nascimento Oliveira |
| Support Opportunities: | Scholarships in Brazil - Scientific Initiation |
| FAPESP's process: | 22/05878-3 - Assessment of the enzymatic, neuromuscular and hemostatic action of Crotalus durissus ruruima (Viperidae: Crotalinae) venom and neutralization by commercial antivenom |
| Grantee: | Poliana de Jesus Demico |
| Support Opportunities: | Scholarships in Brazil - Scientific Initiation |