Ca(2+)-BK channel clusters in olfactory receptor neurons and their role in odour coding

Eur J Neurosci. 2015 Dec;42(11):2985-95. doi: 10.1111/ejn.13095. Epub 2015 Nov 11.


Olfactory receptor neurons (ORNs) have high-voltage-gated Ca(2+) channels whose physiological impact has remained enigmatic since the voltage-gated conductances in this cell type were first described in the 1980s. Here we show that in ORN somata of Xenopus laevis tadpoles these channels are clustered and co-expressed with large-conductance potassium (BK) channels. We found approximately five clusters per ORN and twelve Ca(2+) channels per cluster. The action potential-triggered activation of BK channels accelerates the repolarization of action potentials and shortens interspike intervals during odour responses. This increases the sensitivity of individual ORNs to odorants. At the level of mitral cells of the olfactory bulb, odour qualities have been shown to be coded by first-spike-latency patterns. The system of Ca(2+) and BK channels in ORNs appears to be important for correct odour coding because the blockage of BK channels not only affects ORN spiking patterns but also changes the latency pattern representation of odours in the olfactory bulb.

Keywords: Xenopus laevis; calcium; iberiotoxin; microdomains; voltage-gated calcium channels (VGCC).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Action Potentials / drug effects
  • Action Potentials / physiology
  • Animals
  • Calcium / metabolism
  • Calcium Channels / metabolism
  • Charybdotoxin / pharmacology
  • Large-Conductance Calcium-Activated Potassium Channels / antagonists & inhibitors
  • Large-Conductance Calcium-Activated Potassium Channels / metabolism*
  • Larva
  • Microscopy, Confocal
  • Neurotransmitter Agents / pharmacology
  • Olfactory Bulb / drug effects
  • Olfactory Bulb / physiology
  • Olfactory Perception / drug effects
  • Olfactory Perception / physiology
  • Olfactory Receptor Neurons / drug effects
  • Olfactory Receptor Neurons / physiology*
  • Patch-Clamp Techniques
  • Peptides / pharmacology
  • Smell / drug effects
  • Smell / physiology*
  • Tissue Culture Techniques
  • Voltage-Sensitive Dye Imaging
  • Xenopus laevis


  • Calcium Channels
  • Large-Conductance Calcium-Activated Potassium Channels
  • Neurotransmitter Agents
  • Peptides
  • Charybdotoxin
  • iberiotoxin
  • Calcium