Antidromic-rectifying gap junctions amplify chemical transmission at functionally mixed electrical-chemical synapses

Nat Commun. 2017 Mar 20;8:14818. doi: 10.1038/ncomms14818.

Abstract

Neurons communicate through chemical synapses and electrical synapses (gap junctions). Although these two types of synapses often coexist between neurons, little is known about whether they interact, and whether any interactions between them are important to controlling synaptic strength and circuit functions. By studying chemical and electrical synapses between premotor interneurons (AVA) and downstream motor neurons (A-MNs) in the Caenorhabditis elegans escape circuit, we found that disrupting either the chemical or electrical synapses causes defective escape response. Gap junctions between AVA and A-MNs only allow antidromic current, but, curiously, disrupting them inhibits chemical transmission. In contrast, disrupting chemical synapses has no effect on the electrical coupling. These results demonstrate that gap junctions may serve as an amplifier of chemical transmission between neurons with both electrical and chemical synapses. The use of antidromic-rectifying gap junctions to amplify chemical transmission is potentially a conserved mechanism in circuit functions.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Caenorhabditis elegans / genetics
  • Caenorhabditis elegans / metabolism
  • Caenorhabditis elegans / physiology*
  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / metabolism
  • Electrical Synapses / physiology*
  • Gap Junctions / physiology*
  • Interneurons / physiology
  • Models, Neurological
  • Motor Neurons / physiology
  • Mutation
  • Synapses / physiology*
  • Synaptic Potentials / physiology
  • Synaptic Transmission / physiology*

Substances

  • Caenorhabditis elegans Proteins