[Mechanism of action of myotoxins isolated from snake venoms].

Abstract

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.

• Authors: J M Gutiérrez, L Cerdas
• Journal: Revista de biologia tropical (Rev Biol Trop) Vol. 32 Issue 2 Pg. 213-22 (Nov 1984) ISSN: 0034-7744 [Print] Costa Rica
• Vernacular Title: Mecanismo de acción de miotoxinas aisladas de venenos de serpientes.
• PMID: 6400184 (Publication Type: English Abstract, Journal Article, Review)

Chemical References

• Crotalid Venoms
• Elapid Venoms
• Naphthols
• Snake Venoms
• Toxins, Biological
• crotalid hemorrhagic factor B
• viriditoxin
• notexin
• taipoxin
• Crotoxin
• crotamine
• Calcium

Topics

• Animals
• Calcium (metabolism)
• Cell Membrane (drug effects)
• Crotalid Venoms (pharmacology)
• Crotoxin (pharmacology)
• Elapid Venoms (pharmacology)
• Muscle Contraction (drug effects)
• Muscles (drug effects, pathology)
• Naphthols (pharmacology)
• Necrosis
• Snake Venoms (analysis)
• Toxins, Biological (isolation & purification, pharmacology)