Visualization by high resolution immunoelectron microscopy of the transient receptor potential vanilloid-1 at inhibitory synapses of the mouse dentate gyrus

PLoS One. 2015 Mar 16;10(3):e0119401. doi: 10.1371/journal.pone.0119401. eCollection 2015.

Abstract

We have recently shown that the transient receptor potential vanilloid type 1 (TRPV1), a non-selective cation channel in the peripheral and central nervous system, is localized at postsynaptic sites of the excitatory perforant path synapses in the hippocampal dentate molecular layer (ML). In the present work, we have studied the distribution of TRPV1 at inhibitory synapses in the ML. With this aim, a preembedding immunogold method for high resolution electron microscopy was applied to mouse hippocampus. About 30% of the inhibitory synapses in the ML are TRPV1 immunopositive, which is mostly localized perisynaptically (∼60% of total immunoparticles) at postsynaptic dendritic membranes receiving symmetric synapses in the inner 1/3 of the layer. This TRPV1 pattern distribution is not observed in the ML of TRPV1 knock-out mice. These findings extend the knowledge of the subcellular localization of TRPV1 to inhibitory synapses of the dentate molecular layer where the channel, in addition to excitatory synapses, is present.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Body / metabolism
  • Dendrites / metabolism*
  • Dentate Gyrus / metabolism*
  • Female
  • Gene Knockout Techniques
  • Inhibitory Postsynaptic Potentials
  • Male
  • Mice
  • Microscopy, Immunoelectron
  • Synapses / metabolism*
  • TRPV Cation Channels / genetics*
  • TRPV Cation Channels / metabolism*

Substances

  • TRPV Cation Channels
  • TRPV1 protein, mouse

Grants and funding

P. Grandes’ laboratory is provided by Ministerio de Economía y Competitividad (BFU2012-33334); Basque Government grant IT764-13; University of the Basque Country (UFI11/41) and by Red de Trastornos Adictivos, RETICS, Instituto de Salud Carlos III, grant number: RD07/0001/2001, RD12/0028/0004. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.