... concentration of the radiolabeled toxin was determinedaccording to the specific activity of the 125I corresponding to2500–3000 d.p.m.Æfmol)1 of monoiodotoxin, depending on the age of the radiotoxin and ... similar to the anti-insect depressant toxin,LqhIT2, in its toxic symptoms induced in blowfly larvae, and the ability to compete for the binding site of the excitatory toxin, Bj-xtrIT, in insect NaChs ... Nonspecific toxin binding was determined in the presence of a high concentration of unlabeled toxin, asspecified in figure legends, and consisted typically of 5–15% of total binding. Equilibrium...