[3H]Batrachotoxinin A 20.alpha.-benzoate binding to voltage-sensitive sodium channels: a rapid and quanitative assay for local anesthetic activity in a variety of drugs

Abstract

[3H]Batrachotoxinin A benzoate ([3H]BTX-B) binds with high affinity to sites on voltage-dependent Na channels in a vesicular preparation from guinea pig cerebral cortex. In this preparation, local anesthetics competitively antagonize the binding of [3H]BTX-B. The potencies of some 40 classical local anesthetics and a variety of catecholamine, histamine, serotonin, adenosine, GABA, Gly, acetylcholine, and Ca antagonists, tranquilizers, antidepressants, barbiturates, anticonvulsants, steroids, vasodilators, antiinflammatories, anticoagulants, analgesics and other agents were determined. An excellent correlation with the known local anesthetic activity of many of these agents indicate that antagonism of binding of [3H]BTX-B binding provides a rapid, quantitative and facile method for the screening and investigation of local anesthetic activity.