Local potassium signaling couples neuronal activity to vasodilation in the brain

Nat Neurosci. 2006 Nov;9(11):1397-1403. doi: 10.1038/nn1779.


The mechanisms by which active neurons, via astrocytes, rapidly signal intracerebral arterioles to dilate remain obscure. Here we show that modest elevation of extracellular potassium (K+) activated inward rectifier K+ (Kir) channels and caused membrane potential hyperpolarization in smooth muscle cells (SMCs) of intracerebral arterioles and, in cortical brain slices, induced Kir-dependent vasodilation and suppression of SMC intracellular calcium (Ca2+) oscillations. Neuronal activation induced a rapid (<2 s latency) vasodilation that was greatly reduced by Kir channel blockade and completely abrogated by concurrent cyclooxygenase inhibition. Astrocytic endfeet exhibited large-conductance, Ca2+-sensitive K+ (BK) channel currents that could be activated by neuronal stimulation. Blocking BK channels or ablating the gene encoding these channels prevented neuronally induced vasodilation and suppression of arteriolar SMC Ca2+, without affecting the astrocytic Ca2+ elevation. These results support the concept of intercellular K+ channel-to-K+ channel signaling, through which neuronal activity in the form of an astrocytic Ca2+ signal is decoded by astrocytic BK channels, which locally release K+ into the perivascular space to activate SMC Kir channels and cause vasodilation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arterioles / innervation
  • Arterioles / physiology
  • Astrocytes / physiology
  • Brain / physiology*
  • Calcium / metabolism
  • Cerebrovascular Circulation / physiology*
  • Electric Stimulation
  • Electrophysiology
  • In Vitro Techniques
  • Male
  • Membrane Potentials / physiology
  • Muscle, Smooth, Vascular / innervation
  • Muscle, Smooth, Vascular / physiology
  • Neurons / physiology*
  • Patch-Clamp Techniques
  • Potassium / physiology*
  • Potassium Channels, Inwardly Rectifying / physiology*
  • Rats
  • Rats, Sprague-Dawley
  • Signal Transduction / physiology*
  • Vasodilation / physiology*


  • Potassium Channels, Inwardly Rectifying
  • Potassium
  • Calcium