Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If You Use a Screen Reader

This content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.

Both Barium and Calcium Activate Neuronal Potassium Currents

Angeles B. Ribera and Nicholas C. Spitzer
Proceedings of the National Academy of Sciences of the United States of America
Vol. 84, No. 18 (Sep. 15, 1987), pp. 6577-6581
Stable URL: http://www.jstor.org/stable/29883
Page Count: 5
  • Read Online (Free)
  • Subscribe ($19.50)
  • Cite this Item
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Both Barium and Calcium Activate Neuronal Potassium Currents
Preview not available

Abstract

Amphibian spinal neurons in culture possess both rapidly inactivating and sustained calcium-dependent potassium current components, similar to those described for other cells. Divalent cation-dependent whole-cell outward currents were isolated by subtracting the voltage-dependent potassium currents recorded from Xenopus laevis neurons in the presence of impermeant cadmium (100-500 μ M) from the currents produced without cadmium but in the presence of permeant divalent cations (50-100 μ M). These concentrations of permeant ions were low enough to avoid contamination by macroscopic inward currents through calcium channels. Calcium-dependent potassium currents were reduced by 1 μ M tetraethylammonium. These currents can also be activated by barium or strontium. Barium as well as calcium activated outward currents in young neurons (6-8 hr) and in relatively mature neurons (19-26 hr in vitro). However, barium influx appeared to suppress the sustained voltage-dependent potassium current in most cells. Barium also activated at least one class of potassium channels observed in excised membrane patches, while blocking others. The blocking action may have masked and hindered detection of the stimulatory action of barium in other systems.

Page Thumbnails

  • Thumbnail: Page 
6577
    6577
  • Thumbnail: Page 
6578
    6578
  • Thumbnail: Page 
6579
    6579
  • Thumbnail: Page 
6580
    6580
  • Thumbnail: Page 
6581
    6581