Properties of Ba2+ currents arising from human α1E and α1Eβ3 constructs expressed in HEK293 cells: physiology, pharmacology, and comparison to native T-type Ba2+ currents

  • Yasunori M. Nakashima
  • , Slobodan M. Todorovic
  • , Alexei Pereverzev
  • , Juergen Hescheler
  • , Toni Schneider
  • , Christopher J. Lingle

Research output: Contribution to journalArticlepeer-review

Abstract

Currents arising from human α1E and α1Eβ3 Ca2+ channel subunits expressed in HEK-293 cells were examined with whole-cell recording methods and compared to properties of T-current in DRG neurons studied under identical ionic conditions. Coexpression of α1E subunit with the β3 subunit shifted activation to more negative potentials. Activation and deactivation of both variants were comparable at most voltages, with deactivation becoming faster, but less voltage-dependent, at more negative potentials. The inactivation time course for α1E and α1Eβ3 currents was best described by at least two exponential components. Recovery from inactivation was markedly voltage-dependent and similar for both constructs. In comparison to α1E and α1Eβ3 constructs, T current activation was shifted to more negative potentials, activation was typically slower, deactivation exhibited a steeper voltage-dependence, and recovery from inactivation was less voltage-dependent. Over most of the activation range, native T current inactivated more completely and in a single exponential fashion. Despite some pharmacological similarities (e.g. octanol, barbiturates) between α1E and T-type currents, aspects of blockade by amiloride and phenytoin appear to distinguish α1E current from T-type currents. The results define several distinguishing features of α1E currents that distinguish them from native T-type currents. Copyright (C) 1998 Elsevier Science Ltd.

Original languageEnglish
Pages (from-to)957-972
Number of pages16
JournalNeuropharmacology
Volume37
Issue number8
DOIs
StatePublished - Aug 1998

Keywords

  • Ca channel subunit
  • Ca currents
  • Ca currents (R-type)
  • Ca currents (T-type)
  • LVA current
  • α1E

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