The first radiolabeled histamine H₃ receptor antagonist, [¹²⁵I]iodophenpropit: Saturable and reversible binding to rat cortex membranes

Abstract

We describe the binding to rat cortex membranes of [¹²⁵I]iodophenpropit, the first radiolabeled histamine H₃ antagonist. The binding of [¹²⁵I]iodophenpropit is selective, saturable, readily reversible, and of high affinity (K_D 0.32 nM; B_max 209 fmol/mg of protein). Specific binding at a concentration of 0.3 nM accounted for 45–55% of the total binding. [¹²⁵I]Iodophenpropit seems to fulfill the criteria for a suitable ligand for histamine H₃ receptor binding studies.