Intracellular chloride concentration of the mouse vomeronasal neuron.

Sangseong Kim,Limei Ma,Sean Mckinney,Jay Unruh,C Ron Yu

doi:10.1186/s12868-015-0230-y

Sangseong Kim, Limei Ma + Show 3 more

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https://doi.org/10.1186/s12868-015-0230-y

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Abstract

BackgroundThe vomeronasal organ (VNO) is specialized in detecting pheromone and heterospecific cues in the environment. Recent studies demonstrate the involvement of multiple ion channels in VNO signal transduction, including the calcium-activated chloride channels (CACCs). Opening of CACCs appears to result in activation of VNO neuron through outflow of Cl− ions. However, the intracellular Cl− concentration remains undetermined.ResultsWe used the chloride ion quenching dye, MQAE, to measure the intracellular Cl− concentration of VNO neuron in live VNO slices. The resting Cl− concentration in the VNO neurons is measured at 84.73 mM. Urine activation of the VNO neurons causes a drop in Cl− concentration, consistent with the notion of an efflux of Cl− to depolarize the cells. Similar observation is made for VNO neurons from mice with deletion of the transient receptor potential canonical channel 2 (TRPC2), which have a resting Cl− concentrations at 81 mM.ConclusionsThe VNO neurons rest at high intracellular Cl− concentration, which can lead to depolarization of the cell when chloride channels open. These results also provide additional support of TRPC2-independent pathway of VNO activation.

Highlights

The vomeronasal organ (VNO) is specialized in detecting pheromone and heterospecific cues in the environment
The vomeronasal organ is involved in detection of pheromone cues, which are contained in bodily fluids and excretions
Existing evidence suggests that Calcium-activated chloride channels (CACC) is involved in VNO signal transduction [12,13,14]

Summary

Introduction

The vomeronasal organ (VNO) is specialized in detecting pheromone and heterospecific cues in the environment. Recent studies demonstrate the involvement of multiple ion channels in VNO signal transduction, including the calcium-activated chloride channels (CACCs). Opening of CACCs appears to result in activation of VNO neuron through outflow of Cl− ions. The mammalian olfactory sensory neurons maintain an intracellular Cl− concentration of ~69 mM [1] or 40–50 mM [2]. Odor stimulation activates the cyclic nucleotide-gated (CNG) channel and results in calcium influx activating calcium-activated chloride channels (CACCs) to depolarize the neurons [3,4,5,6,7,8,9,10]. Recent studies have revealed the involvement of a chloride conductance in VNO activation. In VNO neuron, urinary stimulus appears to activate CACC currents.

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