Irreversible and reversible blockade of IMR32 calcium channel currents by synthetic MVIIA and iodinated MVIIC omega-conopeptides.
The actions of two omega-conopeptides on high-voltage-activated calcium channel currents in differentiated human neuroblastoma IMR32 cells were investigated. Similar to the previously reported action of omega-conopeptide GVIA, omega-conopeptide MVIIA irreversibly blocks IMR32 HVA calcium channel currents at low concentrations. Unlike GVIA action, however, novel omega-conopeptide SNX-260 (iodinated MVIIC) reversibly blocks these currents, also at low concentrations, with an IC50 near 50 nM. Different omega-conopeptides may be potent blockers of HVA calcium channel currents yet act either reversibly or irreversibly in a single cell.
Fox
J A
JA
Axon Instruments Inc., Foster City, CA 94404, USA.
D002121:Calcium Channel Blockers / Q000494:pharmacology*; D015220:Calcium Channels / Q000502:physiology*; D004553:Electric Conductivity; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D008978:Mollusk Venoms; D009447:Neuroblastoma; D010455:Peptides / Q000494:pharmacology*; D014407:Tumor Cells, Cultured; D020960:omega-Conotoxins
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D036341:Intercellular Signaling Peptides and Proteins; D008978:Mollusk Venoms; D010455:Peptides; C093823:SNX 260; D020960:omega-Conotoxins; C078452:ziconotide