Overview
- Lewis, R.J. et al. (2000) J. Biol. Chem. 275, 35335.
Alomone Labs ω-Conotoxin CVIA inhibits CaV2.2 channels expressed in Xenopus oocytes.A. Time course of ω-Conotoxin CVIA (#STC-750) action on maximum CaV2.2 channels (α1B + α2δ1 + β1) current elicited in 2 mM Ba2+. Peak current amplitudes were plotted as a function of time. Membrane potential was held at -100 mV and oocytes were stimulated by a 100 ms voltage step to 50 mV. 50 nM ω-Conotoxin CVIA was perfused as indicated by the bar (green) for 5 min. B. Superimposed examples of CaV2.2 channel maximum peak current in the absence (control) and presence (green) of 50 nM ω-Conotoxin CVIA (taken from the experiment in A).
CaV channels mediate Ca2+ influx through cell membrane as a response to membrane depolarization. N-type channels require strong depolarization for activation and are mostly expressed in neurons where they initiate neurotransmission in fast synapses and mediate Ca2+ entry into cell bodies and dendrites1.
ω-conotoxin CVIA is a 27 amino acid neuropeptide2 belonging to a class of four new ω-conotoxins (CVIA-D) extracted from the venom of the Conus Catus snail. These peptides inhibit neuronal voltage sensitive Ca2+ channels in mammals. Interestingly, unlike other ω-conotoxins CVID has a loop 4 sequence and has the highest affinity to N-type channels over other types of Ca2+ channels while CVIA shows a lower affinity to N-type channels.
CVIA is efficient in the management of severe pain, has clinical potential in ischemic brain injury and was also found to inhibit the contraction of electrically stimulated rat vas deferens with an IC50 of 205 nM3.
