title: BDNF regulates the intrinsic excitability of cortical neurons.
abstract: Neocortical pyramidal neurons respond to prolonged activity blockade by modulating their balance of inward and outward currents to become more sensitive to synaptic input, possibly as a means of homeostatically regulating firing rates during periods of intense change in synapse number or strength. Here we show that this activity-dependent regulation of intrinsic excitability depends on the neurotrophin brain-derived neurotrophic factor (BDNF). In experiments on rat visual cortical cultures, we found that exogenous BDNF prevented, and a TrkB-IgG fusion protein reproduced, the change in pyramidal neuron excitability produced by activity blockade. Most of these effects were also observed in bipolar interneurons, indicating a very general role for BDNF in regulating neuronal excitability. Moreover, earlier work has demonstrated that BDNF mediates a different kind of homeostatic plasticity present in these same cultures: scaling of the quantal amplitude of AMPA-mediated synaptic inputs up or down as a function of activity. Taken together, these results suggest that BDNF may be the signal controlling a coordinated regulation of synaptic and intrinsic properties aimed at allowing cortical networks to adapt to long-lasting changes in activity.
authors.affiliation: Department of Biology and Center for Complex Systems, Brandeis University, Waltham, Massachusetts 02454-9110, USA.
authors.forename: N S
authors.initials: NS
authors.lastname: Desai
authors.forename: L C
authors.initials: LC
authors.lastname: Rutherford
authors.forename: G G
authors.initials: GG
authors.lastname: Turrigiano
mesh_terms: D000818:Animals; D001923:Brain Chemistry / Q000502:physiology; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism / Q000502:physiology*; D002540:Cerebral Cortex / Q000166:cytology / Q000502:physiology*; D004594:Electrophysiology; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000502:physiology; D009473:Neuronal Plasticity / Q000187:drug effects; D009474:Neurons / Q000378:metabolism / Q000502:physiology*; D018408:Patch-Clamp Techniques; D051381:Rats; D013569:Synapses / Q000502:physiology; D013779:Tetrodotoxin / Q000494:pharmacology; D014793:Visual Cortex / Q000166:cytology / Q000502:physiology; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000494:pharmacology
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D013779:Tetrodotoxin; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid