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PMID: 10200319 Published · ppublish English Journal Article Research Support, Non-U.S. Gov't

An apamin-sensitive Ca2+-activated K+ current in hippocampal pyramidal neurons.

Proceedings of the National Academy of Sciences of the United States of America ·Vol. 96 ·No. 8 ·1999-04-13 ·Pages 4662-7

Stocker M, Krause M, Pedarzani P

Abstract

In hippocampal and other cortical neurons, action potentials are followed by afterhyperpolarizations (AHPs) generated by the activation of small-conductance Ca2+-activated K+ channels (SK channels). By shaping the neuronal firing pattern, these AHPs contribute to the regulation of excitability and to the encoding function of neurons. Here we report that CA1 pyramidal neurons express an AHP current that is suppressed by apamin and is involved in the control of repetitive firing. This current presents distinct kinetic and pharmacological features, and it is modulated differently than the apamin-insensitive slow AHP current. Furthermore, our in situ hybridizations show that the apamin-sensitive SK subunits are expressed in CA1 pyramidal neurons, providing a potential molecular correlate to the apamin-sensitive AHP current. Altogether, these results clarify the discrepancy between the reported high density of apamin-binding sites in the CA1 region and the apparent lack of an apamin-sensitive current in CA1 pyramidal neurons, and they may explain the effects of this toxin on hippocampal synaptic plasticity and learning.

MeSH Terms
Animals Apamin/pharmacology Base Sequence Bicuculline/pharmacology Cyclic AMP/analogs & derivatives,pharmacology Hippocampus/physiology In Situ Hybridization Male Membrane Potentials/drug effects,physiology Molecular Sequence Data Oligodeoxyribonucleotides/chemistry Oligodeoxyribonucleotides, Antisense/chemistry Potassium Channels/drug effects,genetics,physiology Potassium Channels, Voltage-Gated Pyramidal Cells/drug effects,physiology Rats Thionucleotides/pharmacology
Chemicals
Oligodeoxyribonucleotides Oligodeoxyribonucleotides, Antisense Potassium Channels Potassium Channels, Voltage-Gated Thionucleotides potassium channel protein I(sk) Apamin 8-((4-chlorophenyl)thio)cyclic-3',5'-AMP Cyclic AMP Bicuculline
Authors & Affiliations
3 authors, click to expand affiliations / ORCID
Stocker M
Max Planck Institute for Experimental Medicine, Department of Molecular Biology of Neuronal Signals, 37075 Göttingen, Germany.
Krause M
Pedarzani P
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Article Info
Journal
Proceedings of the National Academy of Sciences of the United States of America
Abbr.
Proc Natl Acad Sci U S A
ISSN
0027-8424
DOI
10.1073/pnas.96.8.4662
Published
1999-04-13
Pages
4662-7
Language
English
Region
United States
NLM ID
7505876
PMCID
PMC16389
Subset
IM
External Links
PubMed source DOI: 10.1073/pnas.96.8.4662 PMC Full Text View journal details
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