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The Life Cycle of Ca2+ Ions in Dendritic Spines

2002; Cell Press; Volume: 33; Issue: 3 Linguagem: Inglês

10.1016/s0896-6273(02)00573-1

1097-4199

Bernardo L. Sabatini, Thomas G. Oertner, Karel Svoboda,

Neural dynamics and brain function

Abstract Spine Ca 2+ is critical for the induction of synaptic plasticity, but the factors that control Ca 2+ handling in dendritic spines under physiological conditions are largely unknown. We studied [Ca 2+ ] signaling in dendritic spines of CA1 pyramidal neurons and find that spines are specialized structures with low endogenous Ca 2+ buffer capacity that allows large and extremely rapid [Ca 2+ ] changes. Under physiological conditions, Ca 2+ diffusion across the spine neck is negligible, and the spine head functions as a separate compartment on long time scales, allowing localized Ca 2+ buildup during trains of synaptic stimuli. Furthermore, the kinetics of Ca 2+ sources governs the time course of [Ca 2+ ] signals and may explain the selective activation of long-term synaptic potentiation (LTP) and long-term depression (LTD) by NMDA-R-mediated synaptic Ca 2+ .