TY - JOUR
T1 - SK channels and NMDA receptors form a Ca2+-mediated feedback loop in dendritic spines
AU - Ngo-Anh, Thu Jennifer
AU - Bloodgood, Brenda L.
AU - Lin, Michael
AU - Sabatini, Bernardo L.
AU - Maylie, James
AU - Adelman, John P.
PY - 2005/5
Y1 - 2005/5
N2 - Small-conductance Ca2+-activated K+ channels (SK channels) influence the induction of synaptic plasticity at hippocampal CA3-CA1 synapses. We find that in mice, SK channels are localized to dendritic spines, and their activity reduces the amplitude of evoked synaptic potentials in an NMDA receptor (NMDAR)-dependent manner. Using combined two-photon laser scanning microscopy and two-photon laser uncaging of glutamate, we show that SK channels regulate NMDAR-dependent Ca2+ influx within individual spines. SK channels are tightly coupled to synaptically activated Ca2+ sources, and their activity reduces the amplitude of NMDAR-dependent Ca2+ transients. These effects are mediated by a feedback loop within the spine head; during an excitatory postsynaptic potential (EPSP), Ca2+ influx opens SK channels that provide a local shunting current to reduce the EPSP and promote rapid Mg2+ block of the NMDAR. Thus, blocking SK channels facilitates the induction of long-term potentiation by enhancing NMDAR-dependent Ca2+ signals within dendritic spines.
AB - Small-conductance Ca2+-activated K+ channels (SK channels) influence the induction of synaptic plasticity at hippocampal CA3-CA1 synapses. We find that in mice, SK channels are localized to dendritic spines, and their activity reduces the amplitude of evoked synaptic potentials in an NMDA receptor (NMDAR)-dependent manner. Using combined two-photon laser scanning microscopy and two-photon laser uncaging of glutamate, we show that SK channels regulate NMDAR-dependent Ca2+ influx within individual spines. SK channels are tightly coupled to synaptically activated Ca2+ sources, and their activity reduces the amplitude of NMDAR-dependent Ca2+ transients. These effects are mediated by a feedback loop within the spine head; during an excitatory postsynaptic potential (EPSP), Ca2+ influx opens SK channels that provide a local shunting current to reduce the EPSP and promote rapid Mg2+ block of the NMDAR. Thus, blocking SK channels facilitates the induction of long-term potentiation by enhancing NMDAR-dependent Ca2+ signals within dendritic spines.
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U2 - 10.1038/nn1449
DO - 10.1038/nn1449
M3 - Article
C2 - 15852011
AN - SCOPUS:17844385283
VL - 8
SP - 642
EP - 649
JO - Nature Neuroscience
JF - Nature Neuroscience
SN - 1097-6256
IS - 5
ER -