Mechanism of the excitatory Cl- response in mouse olfactory receptor neurons

Johannes Reisert, Jun Lai, King-Wai Yau, Jonathan Bradley

Research output: Contribution to journalArticle

Abstract

In vertebrate olfactory receptor neurons (ORNs), the odorant-triggered receptor current flows through two distinct ion channels on the sensory cilia: Ca2+ influx through a cyclic nucleotide-gated (CNG) channel followed by Cl- efflux through a Ca2+-activated anion channel. The excitatory Cl- current amplifies the small CNG current and crucially depends on a high intracellular Cl- concentration. We show here that a Na+-K+-2Cl- cotransporter, NKCC1, is required for this Cl- current, in that ORNs deficient in Nkcc1 or incubated with an NKCC blocker (bumetanide) lack the Cl- current. Surprisingly, immunocytochemistry indicates that NKCC1 is located on the somata and dendrites of ORNs rather than the cilia, where transduction occurs. This topography is remarkably similar to the situation in secretory epithelial cells, where basolateral Cl- uptake and apical Cl- efflux facilitate transepithelial fluid movement. Thus, a single functional architecture serves two entirely different purposes, probably underscoring the epithelial origin of the ORNs.

Original languageEnglish (US)
Pages (from-to)553-561
Number of pages9
JournalNeuron
Volume45
Issue number4
DOIs
Publication statusPublished - Feb 17 2005

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ASJC Scopus subject areas

  • Neuroscience(all)

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