GlyRα2, not GlyRα3, modulates the receptive field surround of OFF retinal ganglion cells.
GlyRα2, not GlyRα3, modulates the receptive field surround of OFF retinal ganglion cells.
复制标题
GlyRα2，而不是GlyRα3，调节OFF 视网膜神经节细胞的感受野周围。
DOI：
10.1017/s0952523815000280
复制
发表时间：
2015
影响因子：
1.9
通讯作者：
McCall,MaureenA
中科院分区：
文献类型：
--
作者：
Zhang,Chi;Nobles,ReginaD;McCall,MaureenA
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−/−), GlyRα3 (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 GlyRα knockouts (Glra2−/−, Glra3−/− and Glra2/3−/−) show that GlyRα2 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.
