Báo cáo Y học: Variations in receptor site-3 on rat brain and insect sodium channels highlighted by binding of a funnel-web spider d-atracotoxin

d-Atracotoxins (d-ACTXs) from Australian funnel-web spiders differ structurally from scorpion a-toxins (ScaTx) but similarly slow sodium current inactivation and compete for their binding to sodium channels at receptor site-3. Characterization of the binding of 125 I-labelled d-ACTX-Hv1a to various sodium channels reveals a decrease in anity for depolarized (0 mV;Kdˆ6.5 ‹1.4 nM) vs.polar-ized ()55 mV;Kdˆ0.6‹0.2nM) rat brain synaptosomes.