Regulation of backpropagating action potentials in mitral cell lateral dendrites by A-type potassium currents

J. M. Christie, Gary Westbrook

Research output: Contribution to journalArticle

54 Citations (Scopus)

Abstract

Dendrodendritic synapses, distributed along mitral cell lateral dendrites, provide powerful and extensive inhibition in the olfactory bulb. Activation of inhibition depends on effective penetration of action potentials into dendrites. Although action potentials backpropagate with remarkable fidelity in apical dendrites, this issue is controversial for lateral dendrites. We used paired somatic and dendritic recordings to measure action potentials in proximal dendritic segments (0-200 μm from soma) and action potential-generated calcium transients to monitor activity in distal dendritic segments (200-600 μm from soma). Somatically elicited action potentials were attenuated in proximal lateral dendrites. The attenuation was not due to impaired access resistance in dendrites or to basal synaptic activity. However, a single somatically elicited action potential was sufficient to evoke a calcium transient throughout the lateral dendrite, suggesting that action potentials reach distal dendritic compartments. Block of A-type potassium channels (IA) with 4-aminopyridine (10 mM) prevented action potential attenuation in direct recordings and significantly increased dendritic calcium transients, particularly in distal dendritic compartments. Our results suggest that IA may regulate inhibition in the olfactory bulb by controlling action potential amplitudes in lateral dendrites.

Original languageEnglish (US)
Pages (from-to)2466-2472
Number of pages7
JournalJournal of Neurophysiology
Volume89
Issue number5
DOIs
StatePublished - May 1 2003

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Dendrites
Action Potentials
Potassium
Olfactory Bulb
Carisoprodol
Calcium
4-Aminopyridine
Potassium Channels
Synapses

ASJC Scopus subject areas

  • Physiology
  • Neuroscience(all)

Cite this

Regulation of backpropagating action potentials in mitral cell lateral dendrites by A-type potassium currents. / Christie, J. M.; Westbrook, Gary.

In: Journal of Neurophysiology, Vol. 89, No. 5, 01.05.2003, p. 2466-2472.

Research output: Contribution to journalArticle

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