Two voltage gated potassium currents on embryonic xenopus skeletal muscle cells growing in culture

• Main Author: Gilbert, Robert William.
• Other Authors: Memorial University of Newfoundland. Faculty of Medicine
• Format: Thesis
• Language: English
• Published: 1990
• Subjects: Potassium channels; Myogenesis; Voltage-clamp techniques (Electrophysiology); Striated muscle > Electric properties; Xenopus > embryology; Muscles; Newfoundland studies; University of Newfoundland
• Online Access: http://collections.mun.ca/cdm/ref/collection/theses3/id/35376

Thesis (M.Sc.) -- Memorial University of Newfoundland, 1990. Medicine Bibliography: leaves 134-143 At least 4 classes of voltage activated potassium currents have been identified on adult frog muscle using macroscopic voltage clamp techniques. This thesis deals with the identification and characterization of two potassium conductances present in the plasma membrane of embryonic Xenopus muscle cells growing in 24 hour old cultures. The tight seal whole cell recording technique was used in this study. One of the currents identified was a hyperpolarization gated inward potassium current thought to be mediated through anomalous rectifying potassium channels. This current activated when the membrane potential was hyperpolarized to values negative to the equilibrium potential for potassium and could be blocked by the external application of 1mM cesium chloride. A second depolarization activated outward current possesses characteristics similar to the delayed rectifier potassium current described on adult frog skeletal muscle ???rations. This conductance activated upon membrane depolarizations positive to membrane potentials of -30mV and could be reduced by the external application of 50mM Tetraethylammonium. Kinetic and pharmacological properties of these currents have been examined.