Elsevier

Neuroscience

Volume 6, Issue 12, December 1981, Pages 2439-2444
Neuroscience

Ionic currents in the somatic membrane of rat dorsal root ganglion neurons —III. Potassium currents

https://doi.org/10.1016/0306-4522(81)90090-7Get rights and content

Abstract

Potassium transmembrane currents induced by membrane depolarization have been studied on isolated dorsal root ganglion neruons of 5–10 day-old rats using the voltage-clamp technique. The neurons were intracellularly dialysed with solutions containing a fixed amount of K+ ions, and the correspondence between the reversal potentials of the measured currents and the theoretical potassium equilibrium potential was determined. Sodium and calcium transmembrane currents were eliminated by replacement of Na+ ions in the extracellular solution and by introduction of fluoride into the cell.

In all cells studied, the total potassium current could be separated into two components—fast and slow (IKf and IKsby changing the holding potential level. IKfwas inactivated comparatively fast obeying first-order kinetics. The dependence h (V) for this current was S-shaped with meanV12 = −75 mV. Therefore, this current could be almost completely switched off at holding potentials more positive than −50 mV. On the contrary, the inactivation of IKs developed very slowly even at stronger depolarizing potential shifts. The mean activation time constants calculated on the basis of Hodgkin-Huxley model for potassium currents were 0.5 ms at zero testing potential for IKf and 40 ms at + 30 mV for IKs.

The reversal potential for IKf determined from instantaneous current-voltage characteristics was close to the equilibrium potential for a potassium electrode. The reversal potential for IKs was shifted in the depolarizing direction by about 25 mV indicating lower selectivity of the corresponding channels.

Reference (13)

There are more references available in the full text version of this article.

Cited by (70)

  • Distinct cellular distributions of Kv4 pore-forming and auxiliary subunits in rat dorsal root ganglion neurons

    2012, Life Sciences
    Citation Excerpt :

    Voltage-gated K+ (Kv) currents in sensory neurons are divided into two major categories; sustained delayed rectifier (KDR) and transient A-type K+ (KA) currents (Kostyuk et al., 1981; Hall et al., 1994; Gold et al., 1996; Yoshimura et al., 1996).

  • Sensory neurons in culture

    2015, Pain Models: Translational Relevance and Applications
View all citing articles on Scopus
View full text