The status of voltage-dependent calcium channels in alpha 1E knock-out mice.

Academic Article

Abstract

  • It has been hypothesized that R-type Ca currents result from the expression of the alpha(1E) gene. To test this hypothesis we examined the properties of voltage-dependent Ca channels in mice in which the alpha(1E) Ca channel subunit had been deleted. Application of omega-conotoxin GVIA, omega-agatoxin IVA, and nimodipine to cultured cerebellar granule neurons from wild-type mice inhibited components of the whole-cell Ba current, leaving a "residual" R current with an amplitude of approximately 30% of the total Ba current. A minor portion of this R current was inhibited by the alpha(1E)-selective toxin SNX-482, indicating that it resulted from the expression of alpha(1E). However, the majority of the R current was not inhibited by SNX-482. The SNX-482-sensitive portion of the granule cell R current was absent from alpha(1E) knock-out mice. We also identified a subpopulation of dorsal root ganglion (DRG) neurons from wild-type mice that expressed an SNX-482-sensitive component of the R current. However as with granule cells, most of the DRG R current was not blocked by SNX-482. We conclude that there exists a component of the R current that results from the expression of the alpha(1E) Ca channel subunit but that the majority of R currents must result from the expression of other Ca channel alpha subunits.
  • Keywords

  • Animals, Barium, Blotting, Western, Calcium, Calcium Channel Blockers, Calcium Channels, R-Type, Cell Survival, Cells, Cultured, Cerebellum, Electrophysiology, Ganglia, Spinal, Ion Transport, Mice, Mice, Inbred C57BL, Mice, Knockout, Neurons, Nimodipine, Patch-Clamp Techniques, Protein Subunits, Spider Venoms, Synaptic Transmission, omega-Agatoxin IVA, omega-Conotoxin GVIA
  • Author List

  • Wilson SM; Toth PT; Oh SB; Gillard SE; Volsen S; Ren D; Philipson LH; Lee EC; Fletcher CF; Tessarollo L
  • Start Page

  • 8566
  • End Page

  • 8571
  • Volume

  • 20
  • Issue

  • 23