TY - JOUR
T1 - Glycinergic feedback enhances synaptic gain in the distal retina
AU - Jiang, Zheng
AU - Yang, Jinnan
AU - Purpura, Lauren A.
AU - Liu, Yufei
AU - Ripps, Harris
AU - Shen, Wen
PY - 2014/4/1
Y1 - 2014/4/1
N2 - Glycine input originates with interplexiform cells, a group of neurons situated within the inner retina that transmit signals centrifugally to the distal retina. The effect on visual function of this novel mechanism is largely unknown. Using gramicidin-perforated patch whole cell recordings, intracellular recordings and specific antibody labelling techniques, we examined the effects of the synaptic connections between glycinergic interplexiform cells, photoreceptors and bipolar cells. To confirm that interplexiform cells make centrifugal feedback on bipolar cell dendrites, we recorded the postsynaptic glycine currents from axon-detached bipolar cells while stimulating presynaptic interplexiform cells. The results show that glycinergic interplexiform cells activate bipolar cell dendrites that express the α3 subunit of the glycine receptor, as well as a subclass of unidentified receptors on photoreceptors. By virtue of their synaptic contacts, glycine centrifugal feedback increases glutamate release from photoreceptors and suppresses the uptake of glutamate by the type 2A excitatory amino acid transporter on photoreceptors. The net effect is a significant increase in synaptic gain between photoreceptors and their second-order neurons.
AB - Glycine input originates with interplexiform cells, a group of neurons situated within the inner retina that transmit signals centrifugally to the distal retina. The effect on visual function of this novel mechanism is largely unknown. Using gramicidin-perforated patch whole cell recordings, intracellular recordings and specific antibody labelling techniques, we examined the effects of the synaptic connections between glycinergic interplexiform cells, photoreceptors and bipolar cells. To confirm that interplexiform cells make centrifugal feedback on bipolar cell dendrites, we recorded the postsynaptic glycine currents from axon-detached bipolar cells while stimulating presynaptic interplexiform cells. The results show that glycinergic interplexiform cells activate bipolar cell dendrites that express the α3 subunit of the glycine receptor, as well as a subclass of unidentified receptors on photoreceptors. By virtue of their synaptic contacts, glycine centrifugal feedback increases glutamate release from photoreceptors and suppresses the uptake of glutamate by the type 2A excitatory amino acid transporter on photoreceptors. The net effect is a significant increase in synaptic gain between photoreceptors and their second-order neurons.
UR - http://www.scopus.com/inward/record.url?scp=84897437424&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84897437424&partnerID=8YFLogxK
U2 - 10.1113/jphysiol.2013.265785
DO - 10.1113/jphysiol.2013.265785
M3 - Article
C2 - 24421349
AN - SCOPUS:84897437424
SN - 0022-3751
VL - 592
SP - 1479
EP - 1492
JO - Journal of Physiology
JF - Journal of Physiology
IS - 7
ER -