A positive feedback synapse from retinal horizontal cells to cone photoreceptors

Skyler Jackman, Norbert Babai, James J. Chambers, Wallace B. Thoreson, Richard H. Kramer

Research output: Contribution to journalArticle

41 Citations (Scopus)

Abstract

Cone photoreceptors and horizontal cells (HCs) have a reciprocal synapse that underlies lateral inhibition and establishes the antagonistic center-surround organization of the visual system. Cones transmit to HCs through an excitatory synapse and HCs feed back to cones through an inhibitory synapse. Here we report that HCs also transmit to cone terminals a positive feedback signal that elevates intracellular Ca2+ and accelerates neurotransmitter release. Positive and negative feedback are both initiated by AMPA receptors on HCs, but positive feedback appears to be mediated by a change in HC Ca2+, whereas negative feedback is mediated by a change in HC membrane potential. Local uncaging of AMPA receptor agonists suggests that positive feedback is spatially constrained to active HC-cone synapses, whereas the negative feedback signal spreads through HCs to affect release from surrounding cones. By locally offsetting the effects of negative feedback, positive feedback may amplify photoreceptor synaptic release without sacrificing HC-mediated contrast enhancement.

Original languageEnglish (US)
Article numbere1001057
JournalPLoS Biology
Volume9
Issue number5
DOIs
StatePublished - May 1 2011
Externally publishedYes

Fingerprint

Retinal Horizontal Cells
Retinal Cone Photoreceptor Cells
cones (retina)
synapse
Synapses
Cones
Feedback
cells
AMPA Receptors
calcium
receptors
Membrane Potentials
neurotransmitters
photoreceptors
Neurotransmitter Agents
membrane potential
Cell membranes
agonists
cell membranes
Cell Membrane

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)
  • Neuroscience(all)

Cite this

A positive feedback synapse from retinal horizontal cells to cone photoreceptors. / Jackman, Skyler; Babai, Norbert; Chambers, James J.; Thoreson, Wallace B.; Kramer, Richard H.

In: PLoS Biology, Vol. 9, No. 5, e1001057, 01.05.2011.

Research output: Contribution to journalArticle

Jackman, Skyler ; Babai, Norbert ; Chambers, James J. ; Thoreson, Wallace B. ; Kramer, Richard H. / A positive feedback synapse from retinal horizontal cells to cone photoreceptors. In: PLoS Biology. 2011 ; Vol. 9, No. 5.
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