Effects of lead on cloned voltage-operated neuronal potassium channels. 1995

M Madeja, and N Binding, and U Musshoff, and O Pongs, and U Witting, and E J Speckmann
Institut für Physiologie, Münster, Germany.

The action of lead (Pb2+) on cloned voltage-operated potassium channels of the rat brain was investigated in oocytes of Xenopus laevis. Pb2+ was found to decrease the potassium currents. This effect was due to a shift of the current-voltage relation in a positive direction (up to 30 mV). The Pb2+ effect appeared at a threshold concentration of about 0.1 mumol/l and was maximal at a concentration of about 30 mumol/l. At a potential of -30 mV, the concentration needed for a 50% reduction of the potassium current was 1.0 mumol/l. The depressant effect of Pb2+ was obtained with all potassium channels tested (Kv1.1, Kv1.2, Kv1.4, Kv2.1, Kv3.4). It was minimal for the Kv2.1 channel and maximal for the Kv1.1 channel at potentials negative to 0 mV. An effect comparable with that of Pb2+ could not be induced by the application of magnesium or calcium. The external application of Pb2+ led to a decrease of potassium currents in outside-out but not in inside-out membrane patches. Overall, Pb2+ had a significant effect on the potassium channels which may contribute to the mechanisms of Pb2+ neurotoxicity.

UI MeSH Term Description Entries
D007854 Lead A soft, grayish metal with poisonous salts; atomic number 82, atomic weight 207.2, symbol Pb.
D008564 Membrane Potentials The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization). Resting Potentials,Transmembrane Potentials,Delta Psi,Resting Membrane Potential,Transmembrane Electrical Potential Difference,Transmembrane Potential Difference,Difference, Transmembrane Potential,Differences, Transmembrane Potential,Membrane Potential,Membrane Potential, Resting,Membrane Potentials, Resting,Potential Difference, Transmembrane,Potential Differences, Transmembrane,Potential, Membrane,Potential, Resting,Potential, Transmembrane,Potentials, Membrane,Potentials, Resting,Potentials, Transmembrane,Resting Membrane Potentials,Resting Potential,Transmembrane Potential,Transmembrane Potential Differences
D009474 Neurons The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM. Nerve Cells,Cell, Nerve,Cells, Nerve,Nerve Cell,Neuron
D002413 Cations, Divalent Positively charged atoms, radicals or groups of atoms with a valence of plus 2, which travel to the cathode or negative pole during electrolysis. Divalent Cations
D003001 Cloning, Molecular The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells. Molecular Cloning
D004594 Electrophysiology The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D012313 RNA A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. (Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed) RNA, Non-Polyadenylated,Ribonucleic Acid,Gene Products, RNA,Non-Polyadenylated RNA,Acid, Ribonucleic,Non Polyadenylated RNA,RNA Gene Products,RNA, Non Polyadenylated
D014982 Xenopus laevis The commonest and widest ranging species of the clawed "frog" (Xenopus) in Africa. This species is used extensively in research. There is now a significant population in California derived from escaped laboratory animals. Platanna,X. laevis,Platannas,X. laevi
D015221 Potassium Channels Cell membrane glycoproteins that are selectively permeable to potassium ions. At least eight major groups of K channels exist and they are made up of dozens of different subunits. Ion Channels, Potassium,Ion Channel, Potassium,Potassium Channel,Potassium Ion Channels,Channel, Potassium,Channel, Potassium Ion,Channels, Potassium,Channels, Potassium Ion,Potassium Ion Channel

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