Neurotoxicity of Micrurus altirostris (Uruguayan coral snake) venom and its neutralization by commercial coral snake antivenom and specific antiserum raised in rabbits.
In this work, we studied the neuromuscular blockade caused by Micrurus altirostris venom (0.1-10 microg/mL) in indirect stimulated chick biventer cervicis and mouse phrenic nerve-diaphragm preparations and the ability of commercial antivenom (Instituto Butantan) and antiserum raised in rabbits to neutralize neurotoxicity and lethality in chicks and mice (LD(50) 0.042 and 0.255 mg/kg), injected i.m. and i.p., respectively, with venom (5 LD(50)):antivenom or antiserum mixtures (n = 6) of 1:1-1:2.5-1:5-1:10-1:20. The venom caused a complete and irreversible neuromuscular blockade in both preparations, inhibited the acetylcholine and carbachol contractures, without interfering on KCl response. The neuromuscular blockade was not Ca(2+) or temperature-dependent and did not affect the response to direct stimulation. Only a venom:antivenom or antiserum ratio of 1:20 neutralized the neuromuscular blockade in vitro and protected chicks and mice against 5 LD(50) of venom. Our results indicated that Micrurus altirostris venom interferes with postsynaptic neurotransmission and that commercial antivenom and rabbit antiserum have low efficacy in neutralizing the neurotoxicity and lethality of this venom.
de Abreu
Valdemir Aparecido
VA
Faculdade de Ciencias Medicas, Universidade Estadual de Campinas, Departamento de Farmacologia, Campinas, Brazil.
Leite
Gildo Bernardo
GB
Oliveira
Caroline Borja
CB
Hyslop
Stephen
S
Furtado
Maria de Fatima Domingos
Mde F
Simioni
Lea Rodrigues
LR
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D000997:Antivenins / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D002217:Carbachol / Q000494:pharmacology; D002645:Chickens; D004546:Elapid Venoms / Q000633:toxicity*; D017815:Elapidae; D006736:Horses; D007106:Immune Sera / Q000494:pharmacology*; D007273:Injections, Intramuscular; D007274:Injections, Intraperitoneal; D007928:Lethal Dose 50; D008297:Male; D051379:Mice; D009119:Muscle Contraction / Q000187:drug effects*; D018482:Muscle, Skeletal / Q000187:drug effects; D010791:Phrenic Nerve / Q000187:drug effects / Q000378:metabolism; D011817:Rabbits; D009435:Synaptic Transmission / Q000187:drug effects; D013696:Temperature
D000997:Antivenins; D004546:Elapid Venoms; D007106:Immune Sera; D002217:Carbachol; D000109:Acetylcholine; D002118:Calcium