Characterization of Six Voltage-Gated K + Currents in Adult Rat Sensory
Neurons.
Gold, Michael S., Michael J. Shuster and Jon D. Levine.
Departments of Medicine, Anatomy, and Oral Surgery and Division of
Neuroscience, University of California, San Francisco CA 94143-0452.
APStracts 2:0361N, 1995.
SUMMARY AND CONCLUSIONS
1) Three voltage-gated K + currents have been described in neurons from
mammalian sensory ganglia: 2 transient and 1 sustained. Because there is
considerable variability in the gating properties of these 3 currents, we have
investigated the possibility that this variability reflects the presence of
additional currents in sensory neurons. 2) Using whole-cell patch clamp
techniques, we provide evidence for the existence of 6 voltage-gated K +
currents in cultured dorsal root ganglion (DRG) neurons from the adult rat.
The 6 currents were identified on the basis of distinct biophysical and
pharmacological properties; three currents are transient (I Af , I Aht and I
As ), and 3 are sustained (I Ki , I Klt and I Kn ). 3) In addition to distinct
biophysical and pharmacological properties, 4 of the 6 currents are
differentially expressed among subpopulations of DRG neurons. I Aht is
selectively expressed in small-diameter neurons. I Ki is expressed more
frequently in neurons with an action potential shoulder, and both I Aht and I
As are selectively co-expressed in neurons that respond to the algogenic agent
capsaicin. I Af is selectively expressed in large-diameter neurons and is the
only current expressed more frequently in neurons without an action potential
shoulder. 4) It is likely that much of apparent variability in the properties
of the 3 voltage-gated K + currents reported previously in vertebrate sensory
neurons can be accounted for by the existence of at least 3 additional
voltage-gated K + currents described in this report.
Received 22 June 1995; accepted in final form 30 November 1995.
APS Manuscript Number J401-5.
Article publication pending J. Neurophysiol.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 23 December 95