title: LTP is accompanied by an enhanced local excitability of pyramidal neuron dendrites.
abstract: The propagation and integration of signals in the dendrites of pyramidal neurons is regulated, in part, by the distribution and biophysical properties of voltage-gated ion channels. It is thus possible that any modification of these channels in a specific part of the dendritic tree might locally alter these signaling processes. Using dendritic and somatic whole-cell recordings, combined with calcium imaging in rat hippocampal slices, we found that the induction of long-term potentiation (LTP) was accompanied by a local increase in dendritic excitability that was dependent on the activation of NMDA receptors. These changes favored the back-propagation of action potentials into this dendritic region with a subsequent boost in the Ca(2+) influx. Dendritic cell-attached patch recordings revealed a hyperpolarized shift in the inactivation curve of transient, A-type K(+) currents that can account for the enhanced excitability. These results suggest an important mechanism associated with LTP for shaping signal processing and controlling dendritic function.
authors.affiliation: Division of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA.
authors.forename: Andreas
authors.initials: A
authors.lastname: Frick
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Magee
authors.forename: Daniel
authors.initials: D
authors.lastname: Johnston
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D003712:Dendrites / Q000502:physiology*; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D006624:Hippocampus / Q000502:physiology; D007473:Ion Channels / Q000502:physiology; D017774:Long-Term Potentiation / Q000502:physiology*; D008568:Memory / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology*; D009924:Organ Culture Techniques; D018408:Patch-Clamp Techniques; D051381:Rats; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism
chemical_list: D007473:Ion Channels; D016194:Receptors, N-Methyl-D-Aspartate; D002118:Calcium