Differential regulation of action potentials by potassium channels

ORCiD

Carlos A. Villalba-Galea: 0000-0002-6489-4651

Document Type

Poster

Conference Title/Conference Publication

Society for Neuroscience Annual Meeting

Organization

Society for Neuroscience

Location

San Diego, CA

Conference Dates

November 12-16, 2016

Date of Presentation

11-13-2016

Abstract

Potassium channels, found throughout the animal and plant kingdoms, play important roles in maintaining membrane potentials and regulating action potential firing, shape, and duration, among other functions. Using the Xenopus laevis (frog) oocyte as model system, we induced high expression of sodium and potassium voltage-gated channels and recorded action potentials by a modification of the two-electrode voltage-clamp recording technique. The voltage-dependent sodium conductance was due to expression of the skeletal muscle NaV channel (NaV1.4) and the delayed rectifier voltage-dependent potassium conductance was due to expression of a Shaker (Kv1) potassium channel. Upon this background, we mixed different potassium-selective ion channels, such as inwardly rectifying potassium (KIR) channels, tandem pore domain (K2P) potassium channels and voltage-gated (KV) channels. We analyzed how these potassium channels affected firing thresholds, reliability of action potential generation, action potential duration, after-hyperpolarization potentials, and refractory periods. Phase plots in which the rate of change of the membrane potential with respect to time (dV/dt) is plotted as a function of membrane potential, revealed the impact of specific potassium channel currents on the rising and falling phases of the action potential. The results of the differential regulation of action potentials by potassium channels expressed in oocytes are compared to action potentials reported in native neurons and muscle cells.

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