Related resources
Search for item elsewhere
University researcher(s)
Academic department(s)
Voltage-dependent calcium channels from brain incorporated into planar lipid bilayers.
Nelson MT, French R, Krueger B
Nature. 1984;308( 5954):77-80.
Access to files
Full-text and supplementary files are not available from Manchester eScholar. Use our list of Related resources to find this item elsewhere. Alternatively, request a copy from the Library's Document supply service.
Abstract
Many important physiological processes, including neurotransmitter release and muscle contraction, are regulated by the concentration of Ca2+ ions in the cell. Levels of cytoplasmic Ca2+ can be elevated by the entry of Ca2+ ions through voltage-dependent channels which are selective for Ca2+, Ba2+ and Sr2+ ions. We have measured currents through single, voltage-dependent calcium channels from rat brain that have been incorporated into planar lipid bilayers. Channel gating was voltage-dependent: membrane depolarization increased the channel open times and decreased the closed times. The channels were selective for divalent cations over monovalent ions. The well-known calcium channel blockers, lanthanum and cadmium, produced a concentration-dependent reduction of the apparent single-channel conductance. Contrary to expectations, the nature of the divalent cation carrying current through the channel affected not only the single-channel conductance, but also the channel open times, with mean open times being shortest for barium.
Keyword(s)
Animals; Cattle; Electric Conductivity; Lipid Bilayers; Rats; drug effects: Ion Channels; drug effects: Membrane Potentials; metabolism: Calcium; pharmacology: Barium; pharmacology: Strontium; physiology: Brain; physiology: Median Eminence