Overview
- Favreau, P. et al. (2001) Biochemistry 40, 14567.
Alomone Labs ω-Conotoxin CnVIIA inhibits CaV2.2 channels heterologously expressed in Xenopus oocytes.A. Time course of ω-Conotoxin CnVIIA (#STC-800) action on CaV2.2 + α2δ1 + β1 currents. Peak current amplitude was plotted as a function of time. Membrane potential was held at -100 mV and oocytes were stimulated by a 100 ms voltage ramp to +50 mV. 1 µM ω-Conotoxin CnVIIA (applied for 180 sec, green) was perfused during the period marked by the bar, as indicated and showed 75% inhibition of control current. B. Superimposed traces of channel current in the absence (black) and presence (green) of 1 µM ω-Conotoxin CnVIIA (taken from experiment in A).
Ca2+ channels have been classified pharmacologically and biophysically. The channels are designated L-, T-, N-, P-, Q- and R-type. Each channel has different voltage ranges and rates for activation and inactivation. The N-type channels are typically inactivated more rapidly than the L-, P- and Q-types1.
ω-Conotoxin CNVIIA is a specific voltage-sensitive calcium channel blocker. It was first isolated from the fish-hunting cone snail Conus consors venom. This peptide consists of 27 amino acid residues folded by 3 disulfide bridges2. ω-Conotoxin CNVIIA exhibits a clear selectivity for N-type specific voltage-sensitive Ca2+ channels2. The therapeutic potential of ω-conotoxins is based on their ability to selectively inhibit mammalian CaV isoforms expressed in ascending pain pathways (especially CaV2.2, which underlies the N-type current present in sensory neurons) and to produce antinociception in animal models of pain3.
