title: Tityustoxin effect on nerve compound action potentials requires extracellular sodium.
abstract: Previous studies have demonstrated that Li(+) ions can substitute for Na(+) in a variety of functional systems. Using the single sucrose-gap recording technique, we measured the nerve compound action potential to study the effects of tityustoxin (an alpha-scorpion toxin that selectively inhibits fast Na(+) channel inactivation) upon removal of extracellular Na(+). Our results suggest that tityustoxin requires the presence of extracellular Na(+) to produce its typical pharmacological effect on Na(+) channel inactivation kinetics, but not to bind to its site.
authors.affiliation: Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Caixa Postal 486, CEP 30161-970, Belo Horizonte, Minas, Gerais, Brazil. cruz@umbi.umd.edu
authors.forename: J S
authors.initials: JS
authors.lastname: Cruz
authors.forename: A C
authors.initials: AC
authors.lastname: Matavel
authors.forename: H M
authors.initials: HM
authors.lastname: Leão-Filho
authors.forename: T
authors.initials: T
authors.lastname: Moraes-Santos
authors.forename: P S
authors.initials: PS
authors.lastname: Beirão
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D005110:Extracellular Space / Q000378:metabolism*; D066298:In Vitro Techniques; D009498:Neurotoxins / Q000494:pharmacology*; D011892:Rana catesbeiana; D012584:Sciatic Nerve / Q000187:drug effects* / Q000502:physiology; D012604:Scorpion Venoms / Q000494:pharmacology*; D012964:Sodium / Q000378:metabolism*; D026941:Sodium Channel Blockers
chemical_list: D009498:Neurotoxins; D012604:Scorpion Venoms; D026941:Sodium Channel Blockers; C003609:tityustoxin; D012964:Sodium