Different types of retinal inhibition have distinct neurotransmitter release properties

Johnnie M. Moore-Dotson, Justin S. Klein, Reece E. Mazade, Erika D Eggers

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Neurotransmitter release varies between neurons due to differences in presynaptic mechanisms such as Ca<sup>2+</sup> sensitivity and timing. Retinal rod bipolar cells respond to brief dim illumination with prolonged glutamate release that is tuned by the differential release of GABA and glycine from amacrine cells in the inner retina. To test if differences among types of GABA and glycine release are due to inherent amacrine cell release properties, we directly activated amacrine cell neurotransmitter release by electrical stimulation. We found that the timing of electrically evoked inhibitory currents was inherently slow and that the timecourse of inhibition from slowest to fastest was GABA<inf>C</inf> receptors ˃ glycine receptors ˃ GABA<inf>A</inf> receptors. Deconvolution analysis showed that the distinct timing was due to differences in prolonged GABA and glycine release from amacrine cells. The timecourses of slow glycine release and GABA release onto GABA<inf>C</inf> receptors were reduced by Ca<sup>2+</sup> buffering with EGTA-AM and BAPTA-AM, but faster GABA release on GABA<inf>A</inf> receptors was not, suggesting that release onto GABA<inf>A</inf> receptors is tightly coupled to Ca<sup>2+</sup>. The differential timing of GABA release was detected from spiking amacrine cells and not nonspiking A17 amacrine cells that form a reciprocal synapse with rod bipolar cells. Our results indicate that release from amacrine cells is inherently asynchronous and that the source of nonreciprocal rod bipolar cell inhibition differs between GABA receptors. The slow, differential timecourse of inhibition may be a mechanism to match the prolonged rod bipolar cell glutamate release and provide a way to temporally tune information across retinal pathways.

Original languageEnglish (US)
Pages (from-to)2078-2090
Number of pages13
JournalJournal of Neurophysiology
Volume113
Issue number7
DOIs
StatePublished - 2015

Fingerprint

Amacrine Cells
Neurotransmitter Agents
gamma-Aminobutyric Acid
Glycine
GABA-A Receptors
Glutamic Acid
Retinal Bipolar Cells
Glycine Receptors
Retinal Rod Photoreceptor Cells
A 17
GABA Receptors
Lighting
Synapses
Electric Stimulation
Retina
Neurons

Keywords

  • Amacrine cell
  • Bipolar cell
  • Release

ASJC Scopus subject areas

  • Physiology
  • Neuroscience(all)

Cite this

Different types of retinal inhibition have distinct neurotransmitter release properties. / Moore-Dotson, Johnnie M.; Klein, Justin S.; Mazade, Reece E.; Eggers, Erika D.

In: Journal of Neurophysiology, Vol. 113, No. 7, 2015, p. 2078-2090.

Research output: Contribution to journalArticle

Moore-Dotson, Johnnie M. ; Klein, Justin S. ; Mazade, Reece E. ; Eggers, Erika D. / Different types of retinal inhibition have distinct neurotransmitter release properties. In: Journal of Neurophysiology. 2015 ; Vol. 113, No. 7. pp. 2078-2090.
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