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Omega-conotoxin CVIB differentially inhibits native and recombinant N- and P/Q-type calcium channels

Leonid Motin1, Takahiro Yasuda, Christina I Schroeder

  • 1School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia.

The European Journal of Neuroscience
|February 8, 2007
PubMed

Insights

Omega-conotoxins CVID and CVIB are potent blockers of voltage-gated calcium channels (VGCCs) in sensory neurons. CVID irreversibly blocks N-type VGCCs, while CVIB reversibly blocks N- and P/Q-type VGCCs, offering distinct research tools.

Area of Science:

  • Neuroscience
  • Pharmacology
  • Molecular Biology

Background:

  • Omega-conotoxins are critical tools for studying voltage-gated calcium channels (VGCCs) in excitable cells.
  • Understanding the differential effects of conotoxins on specific VGCC subtypes is crucial for their application in neuroscience research.

Purpose of the Study:

  • To investigate the blocking capabilities of omega-conotoxins CVID and CVIB on native VGCCs in rat dorsal root ganglion (DRG) neurons.
  • To characterize the reversibility and selectivity of CVID and CVIB against N-type (Ca(V)2.2) and P/Q-type (Ca(V)2.1) VGCCs.

Main Methods:

  • Electrophysiological recordings of whole-cell VGCC currents in rat DRG neurons.
  • Expression of recombinant VGCCs in Xenopus oocytes for functional analysis.
  • Nuclear Magnetic Resonance (NMR) structure determination of CVIB.

Main Results:

  • Both CVID and CVIB inhibited VGCC currents in DRG neurons, with CVID showing irreversible block and CVIB demonstrating reversible block.
  • CVIB selectively blocked N-type and P/Q-type VGCCs, but not R-type (Ca(V)2.3) VGCCs, in oocyte expression systems.
  • Structural analysis revealed differences between CVID and CVIB, potentially explaining their distinct selectivity profiles.

Conclusions:

  • Omega-conotoxins CVID and CVIB exhibit differential blocking properties on VGCC subtypes.
  • CVID and CVIB are valuable pharmacological tools for targeting N- and P/Q-type VGCCs, particularly in sensory neurons involved in pain processing.

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