The voltage-gated anion channels encoded by clh-3 regulate egg laying in C. elegans by modulating motor neuron excitability

J Neurosci. 2014 Jan 15;34(3):764-75. doi: 10.1523/JNEUROSCI.3112-13.2014.

Abstract

CLC-2 is a hyperpolarization-activated, inwardly rectifying chloride channel. Although the properties of the CLC-2 channel have been well characterized, its function in vivo is not well understood. We have found that channels encoded by the Caenorhabditis elegans CLC-2 homolog clh-3 regulate the activity of the spontaneously active hermaphrodite-specific neurons (HSNs), which control the egg-laying behavior. We identified a gain-of-function mutation in clh-3 that increases channel activity. This mutation inhibits egg laying and inhibits HSN activity by decreasing its excitability. Conversely, loss-of-function mutations in clh-3 lead to misregulated egg laying and an increase in HSN excitability, indicating that these channels modulate egg laying by limiting HSN excitability. clh-3-encoded channels are not required for GABAA-receptor-mediated inhibition of the HSN. However, they require low intracellular chloride for HSN inhibition, indicating that they inhibit excitability directly by mediating chloride influx. This mechanism of CLH-3-dependent modulation may be conserved in other neurons in which the driving force favors chloride influx.

MeSH terms

  • Animals
  • Caenorhabditis elegans
  • Caenorhabditis elegans Proteins / physiology*
  • Chloride Channels / physiology*
  • Excitatory Postsynaptic Potentials / physiology*
  • HEK293 Cells
  • Humans
  • Motor Neurons / physiology*
  • Oviposition / physiology*

Substances

  • Caenorhabditis elegans Proteins
  • Chloride Channels
  • ClC-2 chloride channels
  • clh-3 protein, C elegans