The delayed rectifier, IKI, is the major conductance in type I vestibular hair cells across vestibular end organs

Pflugers Arch. 1996 May;432(1):34-42. doi: 10.1007/s004240050102.

Abstract

Hair cells were dissociated from the semicircular canal, utricle, lagena and saccule of white king pigeons. Type I hair cells were identified morphologically based on the ratios of neck width to cuticular plate width (NPR < 0.72) as well as neck width to cell body width (NBR < 0.64). The perforated patch variant of the whole-cell recording technique was used to measure electrical properties from type I hair cells. In voltage-clamp, the membrane properties of all identified type I cells were dominated by a predominantly outward potassium current, previously characterized in semicircular canal as IKI. Zero-current potential, activation, deactivation, slope conductance, pharmacologic and steady-state properties of the complex currents were not statistically different between type I hair cells of different vestibular end organs. The voltage dependence causes a significant proportion of this conductance to be active about the cell's zero-current potential. The first report of the whole-cell activation kinetics of the conductance is presented, showing a voltage dependence that could be best fit by an equation for a single exponential. Results presented here are the first data from pigeon dissociated type I hair cells from utricle, saccule and lagena suggesting that the basolateral conductances of a morphologically identified population of type I hair cells are conserved between functionally different vestibular end organs; the major conductance being a delayed rectifier characterized previously in semicircular canal hair cells as IKI.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 4-Aminopyridine / pharmacology
  • Animals
  • Columbidae
  • Electric Conductivity
  • Electrophysiology
  • Hair Cells, Vestibular / drug effects
  • Hair Cells, Vestibular / physiology*
  • Hair Cells, Vestibular / ultrastructure
  • Homeostasis
  • Kinetics
  • Models, Neurological
  • Potassium / physiology*

Substances

  • 4-Aminopyridine
  • Potassium