Aquaporin-4 water channels in enteric neurons

Mia M. Thi, David C. Spray, Menachem Hanani

Research output: Contribution to journalArticle

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Abstract

Aquaporin-4 is a water channel predominantly found in astrocytes in the central nervous system and is believed to play a critical role in the formation and maintenance of the blood-brain barrier and in water secretion from the brain. As enteric glial cells were found to share several similarities with astrocytes, we hypothesized that enteric glia might also contain aquaporin-4. We used immunohistochemistry to identify aquaporin-4 in the myenteric and submucosal plexuses of the mouse and the rat colon. We found that sub-populations of neurons in both enteric plexuses were positively labeled for human aquaporin-4. Double staining of the enteric ganglia with antibodies to the neuronal marker neurofilament-heavy chain 100 and to aquaporin-4 showed that a minority of myenteric neurons were aquaporin-4 positive (about 12% in the mouse and 13% in the rat). In contrast, in the submucosal plexus significant numbers of neurons were positive for aquaporin-4 (about 79% in both the mouse and the rat). Double labeling for aquaporin-4 and for the glial marker glial fibrillary acidic protein verified that glial cells were not immunoreactive to aquaporin-4. We further confirmed our findings with additional aquaporin-4 antibodies and Western blot analysis. We found that, in addition to expressing aquaporin-4, the myenteric plexus and, to a greater extent, the submucosal plexus both expressed aquaporin-1. We conclude that neurons rather than glial cells contain aquaporin-4 in the colonic enteric plexuses. It is known that submucosal neurons control transport processes in the intestinal mucosa, and the high percentage of aquaporin-4-postive submucosal neurons suggests that aquaporin-4 contributes to this function.

Original languageEnglish (US)
Pages (from-to)448-456
Number of pages9
JournalJournal of Neuroscience Research
Volume86
Issue number2
DOIs
StatePublished - Feb 1 2008

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Keywords

  • AQP1
  • AQP4
  • Mouse
  • Myenteric plexus
  • Rat
  • Submucosal plexus

ASJC Scopus subject areas

  • Cellular and Molecular Neuroscience

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