[Mechanism of action of myotoxins isolated from snake venoms].
Biochemically and pharmacologically, myotoxins isolated from snake venoms can be placed in four main groups: myotoxic phospholipases A, low molecular weight basic toxins, cardiotoxins, and hemorrhagic myotoxins. The myotoxic phospholipases A notexin, taipoxin, crotoxin, and Bothrops asper myotoxin induce muscle necrosis by first affecting the integrity of the plasma membrane, thereby inducing a calcium influx that culminates in cell death. The small basic myotoxin crotamine acts on the voltage-sensitive sodium channels of skeletal muscle sarcolemma, inducing a sodium influx which is responsible for depolarization and contraction of skeletal muscle, as well as for vacuolization of sarcoplasmic reticulum. Cardiotoxins are basic membrane-active polypeptides that disorganize the structure of membranes; the myotoxic activity of cardiotoxins results from their ability to disrupt skeletal muscle sarcolemma. Finally, two hemorrhagic toxins (hemorrhagic toxin b and viriditoxin) are myotoxic; apparently, they secondarily to ischemia which develops in muscular tissue as a consequence of the hemorrhagic action of these toxins.
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002462:Cell Membrane / Q000187:drug effects*; D003435:Crotalid Venoms / Q000494:pharmacology; D003439:Crotoxin / Q000494:pharmacology; D004546:Elapid Venoms / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects; D009132:Muscles / Q000187:drug effects / Q000473:pathology*; D009284:Naphthols / Q000494:pharmacology; D009336:Necrosis; D012910:Snake Venoms / Q000032:analysis*; D014118:Toxins, Biological / Q000302:isolation & purification / Q000494:pharmacology*
D003435:Crotalid Venoms; D004546:Elapid Venoms; D009284:Naphthols; D012910:Snake Venoms; D014118:Toxins, Biological; C041601:crotalid hemorrhagic factor B; C010375:viriditoxin; C005082:notexin; C015523:taipoxin; D003439:Crotoxin; C010563:crotamine; D002118:Calcium
Mecanismo de acción de miotoxinas aisladas de venenos de serpientes.