Action-potential modulation during axonal conduction

Science. 2011 Feb 4;331(6017):599-601. doi: 10.1126/science.1197598.


Once initiated near the soma, an action potential (AP) is thought to propagate autoregeneratively and distribute uniformly over axonal arbors. We challenge this classic view by showing that APs are subject to waveform modulation while they travel down axons. Using fluorescent patch-clamp pipettes, we recorded APs from axon branches of hippocampal CA3 pyramidal neurons ex vivo. The waveforms of axonal APs increased in width in response to the local application of glutamate and an adenosine A(1) receptor antagonist to the axon shafts, but not to other unrelated axon branches. Uncaging of calcium in periaxonal astrocytes caused AP broadening through ionotropic glutamate receptor activation. The broadened APs triggered larger calcium elevations in presynaptic boutons and facilitated synaptic transmission to postsynaptic neurons. This local AP modification may enable axonal computation through the geometry of axon wiring.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Action Potentials* / drug effects
  • Adenosine / metabolism
  • Adenosine / pharmacology
  • Adenosine A1 Receptor Antagonists / pharmacology
  • Animals
  • Astrocytes / metabolism
  • Axons / drug effects
  • Axons / physiology*
  • CA3 Region, Hippocampal / cytology*
  • CA3 Region, Hippocampal / physiology
  • Calcium / metabolism
  • Excitatory Postsynaptic Potentials
  • Glutamic Acid / pharmacology
  • In Vitro Techniques
  • Patch-Clamp Techniques
  • Potassium Channels / metabolism
  • Presynaptic Terminals / physiology
  • Pyramidal Cells / physiology*
  • Rats
  • Rats, Wistar
  • Receptor, Adenosine A1 / metabolism
  • Receptors, AMPA / metabolism
  • Synaptic Transmission*
  • Xanthines / pharmacology
  • gamma-Aminobutyric Acid / pharmacology


  • Adenosine A1 Receptor Antagonists
  • Potassium Channels
  • Receptor, Adenosine A1
  • Receptors, AMPA
  • Xanthines
  • Glutamic Acid
  • gamma-Aminobutyric Acid
  • 1,3-dipropyl-8-cyclopentylxanthine
  • Adenosine
  • Calcium