Polarized microtubule arrays in apical dendrites and axons

Alex C. Kwan, Daniel A. Dombeck, Watt W. Webb

Research output: Contribution to journalArticlepeer-review

77 Scopus citations


The polarization of microtubules within neurons in vivo is crucial in their role of determining the directions and speeds of intracellular transport. More than a decade ago, electron microscopy studies of mature hippocampal cultures indicated that their axons contained microtubules of uniform polarity and that dendrites contained microtubules of mixed polarity. Here, we evaluated polarity distributions in native brain tissues and in cultures by using multiphoton microscopy and second-harmonic generation from microtubules. We confirmed the expected polarized microtubule arrays in axons; however, we also unexpectedly found them ubiquitously in apical dendrites of mature hippocampal CA1 and cortical layer V pyramidal neurons. Some of these organized dendritic microtubule arrays extended for >270 μm with overall polarity of >80%. Our research indicates neurite-specific and age-dependent microtubule organizations that have direct implications for neuronal cargo transport.

Original languageEnglish (US)
Pages (from-to)11370-11375
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number32
StatePublished - Aug 12 2008


  • Intracellular transport
  • Multiphoton microscopy
  • Neurons
  • Second-harmonic generation

ASJC Scopus subject areas

  • General


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