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Developmental profile of SK2 channel expression and function in CA1 neurons
Author(s) -
BallesterosMerino Carmen,
Lin Mike,
Wu Wendy W.,
FerrandizHuertas Clotilde,
Cabañero María J.,
Watanabe Masahiko,
Fukazawa Yugo,
Shigemoto Ryuichi,
Maylie James,
Adelman John P.,
Luján Rafael
Publication year - 2012
Publication title -
hippocampus
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.767
H-Index - 155
eISSN - 1098-1063
pISSN - 1050-9631
DOI - 10.1002/hipo.20986
Subject(s) - apamin , postsynaptic potential , sk channel , excitatory postsynaptic potential , neuroscience , hippocampus , immunogold labelling , hippocampal formation , biology , pyramidal cell , apical dendrite , postsynaptic density , electrophysiology , microbiology and biotechnology , potassium channel , ion channel , anatomy , ultrastructure , inhibitory postsynaptic potential , biophysics , cerebral cortex , receptor , biochemistry
We investigated the temporal and spatial expression of SK2 in the developing mouse hippocampus using molecular and biochemical techniques, quantitative immunogold electron microscopy, and electrophysiology. The mRNA encoding SK2 was expressed in the developing and adult hippocampus. Western blotting and immunohistochemistry showed that SK2 protein increased with age. This was accompanied by a shift in subcellular localization. Early in development (P5), SK2 was predominantly localized to the endoplasmic reticulum in the pyramidal cell layer. But by P30 SK2 was almost exclusively expressed in the dendrites and spines. The level of SK2 at the postsynaptic density (PSD) also increased during development. In the adult, SK2 expression on the spine plasma membrane showed a proximal‐to‐distal gradient. Consistent with this redistribution and gradient of SK2, the selective SK channel blocker apamin increased evoked excitatory postsynaptic potentials (EPSPs) only in CA1 pyramidal neurons from mice older than P15. However, the effect of apamin on EPSPs was not different between synapses in proximal or distal stratum radiatum or stratum lacunosum‐moleculare in adult. These results show a developmental increase and gradient in SK2‐containing channel surface expression that underlie their influence on neurotransmission, and that may contribute to increased memory acquisition during early development. © 2011 Wiley Periodicals, Inc.