Sensitivity and kinetics of signal transmission at the first visual synapse differentially impact visually-guided behavior

Elife. 2015 Apr 16:4:e06358. doi: 10.7554/eLife.06358.

Abstract

In the retina, synaptic transmission between photoreceptors and downstream ON-bipolar neurons (ON-BCs) is mediated by a GPCR pathway, which plays an essential role in vision. However, the mechanisms that control signal transmission at this synapse and its relevance to behavior remain poorly understood. In this study we used a genetic system to titrate the rate of GPCR signaling in ON-BC dendrites by varying the concentration of key RGS proteins and measuring the impact on transmission of signal between photoreceptors and ON-BC neurons using electroretinography and single cell recordings. We found that sensitivity, onset timing, and the maximal amplitude of light-evoked responses in rod- and cone-driven ON-BCs are determined by different RGS concentrations. We further show that changes in RGS concentration differentially impact visually guided-behavior mediated by rod and cone ON pathways. These findings illustrate that neuronal circuit properties can be modulated by adjusting parameters of GPCR-based neurotransmission at individual synapses.

Keywords: G protein signaling; RGS proteins; mouse; neuroscience; retina; synaptic transmission; vision.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Cell Communication
  • Electroretinography
  • Evoked Potentials, Visual / physiology
  • Gene Expression Regulation
  • Kinetics
  • Light
  • Mice
  • Mice, Knockout
  • Photic Stimulation
  • RGS Proteins / deficiency
  • RGS Proteins / genetics
  • Receptors, G-Protein-Coupled / deficiency
  • Receptors, G-Protein-Coupled / genetics
  • Retinal Bipolar Cells / metabolism*
  • Retinal Bipolar Cells / ultrastructure
  • Retinal Cone Photoreceptor Cells / metabolism*
  • Retinal Cone Photoreceptor Cells / ultrastructure
  • Retinal Rod Photoreceptor Cells / metabolism*
  • Retinal Rod Photoreceptor Cells / ultrastructure
  • Single-Cell Analysis
  • Synapses / metabolism*
  • Synapses / ultrastructure
  • Synaptic Transmission / physiology*
  • Vision, Ocular / physiology

Substances

  • RGS Proteins
  • Receptors, G-Protein-Coupled
  • Rgs11 protein, mouse
  • Rgs7 protein, mouse