title: Enhanced transmission of glutamate current flowing from the dendrite to the soma in rat neocortical layer 5 neurons.
abstract: The presence of tetrodotoxin (TTX)-sensitive slowly-inactivating Na+ channels in the dendrites of neocortical layer 5 neurons was tested by focal iontophoresis of glutamate on the dendrite while voltage clamping the soma and proximal dendrite. The glutamate-transmitted current was measured with the voltage clamp circuit. When the soma was depolarized the transmitted current increased indicating voltage-dependent properties in the dendrite. Over 50% of this increased voltage-dependence was blocked by TTX indicating a large portion of the enhanced dendro-somatic current was caused non-inactivating Na+ channel inward rectification. The glutamate-transmitted current measured with a voltage clamp of the soma at firing level was equal to the effective glutamate measured during repetitive firing.
authors.affiliation: Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195-7280, USA.
authors.forename: Wayne E
authors.initials: WE
authors.lastname: Crill
authors.forename: Peter C
authors.initials: PC
authors.lastname: Schwindt
authors.forename: John C
authors.initials: JC
authors.lastname: Oakley
mesh_terms: D000818:Animals; D003712:Dendrites / Q000187:drug effects / Q000502:physiology*; D018698:Glutamic Acid / Q000494:pharmacology / Q000502:physiology*; D019579:Neocortex / Q000502:physiology*; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D015222:Sodium Channels / Q000187:drug effects / Q000502:physiology; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*; D013779:Tetrodotoxin / Q000494:pharmacology
chemical_list: D015222:Sodium Channels; D018698:Glutamic Acid; D013779:Tetrodotoxin