RT Journal Article
SR Electronic
T1 ANALGESIC ω-CONOTOXINS CVIE AND CVIF SELECTIVELY AND VOLTAGE DEPENDENTLY BLOCK RECOMBINANT AND NATIVE N-TYPE CALCIUM CHANNELS
JF Molecular Pharmacology
JO Mol Pharmacol
FD American Society for Pharmacology and Experimental Therapeutics
SP mol.109.058834
DO 10.1124/mol.109.058834
A1 Geza Berecki
A1 Leonid Motin
A1 Alison Haythornthwaite
A1 Simone Vink
A1 Paramjit Bansal
A1 Roger Drinkwater
A1 Ching I Wang
A1 Melissa Moretta
A1 Richard J Lewis
A1 Paul F Alewood
A1 MacDonald J Christie
A1 David J Adams
YR 2009
UL http://molpharm.aspetjournals.org/content/early/2009/11/05/mol.109.058834.abstract
AB N-type Ca2+ channel-selective ω-conotoxins have emerged as potential new drugs for the treatment of chronic pain. In this study, two new ω-conotoxins, CVIE and CVIF, were discovered from a Conus catus cDNA library. Both conopeptides potently displaced 125I-GVIA binding to rat brain membranes. In Xenopus oocytes, CVIE and CVIF potently and selectively inhibited depolarization-activated Ba2+ currents through recombinant N-type (α1B-b/α2δ1/β3) Ca2+ channels. Recovery from block increased with membrane hyperpolarization, indicating that CVIE and CVIF have a higher affinity for channels in the inactivated state. The link between inactivation and the reversibility of ω-conotoxin action was investigated by creating molecular diversity in β subunits: N-type channels with β2a subunits almost completely recovered from CVIE or CVIF block, whereas those with β3 subunits exhibited weak recovery, suggesting that reversibility of the ω-conotoxin block may depend on the type of β subunit isoform. In rat dorsal root ganglion sensory neurons, neither peptide had an effect on low voltage-activated (T-type) channels, but potently and selectively inhibited high voltage-activated N-type Ca2+ channels in a voltage-dependent manner. In rat spinal cord slices, both peptides reversibly inhibited excitatory monosynaptic transmission between primary afferents and dorsal horn superficial lamina neurons. Homology models of CVIE and CVIF suggest that ω-conotoxin/voltage-gated Ca2+ channel interaction is dominated by ionic/electrostatic interactions. In the rat partial sciatic nerve ligation model of neuropathic pain, CVIE and CVIF (1 nM) significantly reduced allodynic behavior. These N-type Ca2+ channel-selective ω-conotoxins are therefore useful as neurophysiological tools and as potential therapeutic agents to inhibit nociceptive pain pathways.The American Society for Pharmacology and Experimental Therapeutics