We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
GlyRα2, not GlyRα3, modulates the receptive field surround of OFF retinal ganglion cells.
- Authors
CHI ZHANG; NOBLES, REGINA D.; McCALL, MAUREEN A.
- Abstract
Receptive fields (RFs) of most retinal ganglion cells (RGCs) consist of an excitatory center and suppressive surround. The RF center arises from the summation of excitatory bipolar cell glutamatergic inputs, whereas the surround arises from lateral inhibitory inputs. In the retina, both gamma amino butyric acid (GABA) and glycine are inhibitory neurotransmitters. A clear role for GABAergic inhibition modulating the RGC RF surround has been demonstrated across species. Glycinergic inhibition is more commonly associated with RF center modulation, although there is some evidence that it may contribute to the RF surround. The synaptic glycinergic chloride channels are formed by three homomeric β and two homomeric α subunits that can be glycine receptor (GlyR) α1, α2, α3, or α4. GlyRα composition is responsible for currents with distinct decay kinetics. Their expression within the inner plexiform laminae and neuronal subtypes also differ. We studied the role of GlyR subunit selective modulation of RGC RF surrounds, using mice lacking GlyRα2 ( Glra2-/- ), GlyR α 3 ( Glra3-/- ), or both ( Glra2/3-/- ). We chose this molecular genetic approach instead of pharmacological manipulation because there are no subunit selective antagonists and strychnine blocks all GlyRs. Comparisons of annulus-evoked responses among wild type (WT) and GlyR α knockouts ( Glra2-/-, Glra3-/- and Glra2/3-/-) show that GlyR α 2 inhibition enhances RF surround suppression and post-stimulus excitation in only WT OFF RGCs. Similarities in the responses in Glra2-/- and Glra2/3-/- RGCs verify these conclusions. Based on previous and current data, we propose that GlyRα2-mediated input uses a crossover inhibitory circuit. Further, we suggest that GlyRα2 modulates the OFF RGC RF center and surround independently. In summary, our results define a selective GlyR subunit-specific control of RF surround suppression in OFF RGCs.
- Publication
Visual Neuroscience, 2015, Vol 32, p1
- ISSN
0952-5238
- Publication type
Article
- DOI
10.1017/S0952523815000280