The neuronal voltage-gated N-type calcium channel (Ca(v)2.2) is a validated target for the treatment of neuropathic pain. A small library of anthranilamide-derived ω-Conotoxin GVIA mimetics bearing the diphenylmethylpiperazine moiety were prepared and tested using three experimental measures of calcium channel blockade. These consisted of a ¹²⁵I-ω-conotoxin GVIA displacement assay, a fluorescence-based calcium response assay with SH-SY5Y neuroblastoma cells, and a whole-cell patch clamp electrophysiology assay with HEK293 cells stably expressing human Ca(v)2.2 channels. A subset of compounds were active in all three assays. This is the first time that compounds designed to be mimics of ω-conotoxin GVIA and found to be active in the ¹²⁵I-ω-conotoxin GVIA displacement assay have also been shown to block functional ion channels in a dose-dependent manner.
Keywords: Ca2+ fluorescence assay; Cav2.2; conotoxin; patch clamp electrophysiology; peptidomimetics; radioligand binding.