All Spiking, Sustained ON Displaced Amacrine Cells Receive Gap-Junction Input from Melanopsin Ganglion Cells

Abstract

Due to an author oversight during the final stages of manuscript preparation, in the version of this article originally published online, the following sentence was inadvertently omitted from the end of the first paragraph of the section ''Synaptic Mechanisms'' on the fifth page: ''By contrast, the intrinsic light responses of ipRGCs (two M1 cells, one M3 cell, one M4 cell, and two M5 cells) were not significantly affected by MFA (p = 0.09; data not shown).'' Thus, the entire paragraph in question should read:The next series of experiments investigated the mechanisms through which ipRGCs transmit photoresponses to displaced amacrine cells. Based on a previous report of tracer coupling [10], we hypothesized that our sustained amacrines received ipRGC input through electrical synapses. To test this, we isolated melanopsin-driven light responses using the glutamate blockers and added 50-100 mM meclofenamic acid (MFA) to block gap junctions [15]. All amacrine cells' (n = 11) melanopsin-mediated light responses were dramatically reduced, indicating a critical role for gap junctions (Figure 6A). By contrast, the intrinsic light responses of ipRGCs (two M1 cells, one M3 cell, one M4 cell, and two M5 cells) were not significantly affected by MFA (p = 0.09; data not shown).The article has now been updated online to include the missing sentence. The authors apologize for the inconvenience.

A Cre Mouse Line for Probing Irradiance- and Direction-Encoding Retinal Networks

“…Because these ACs are melanopsin-immunonegative (Figs. 3 B , 5 G ), our findings parallel those of Reifler et al (2015) in suggesting that the sluggish depolarizing response seen under these recording conditions derives from electrical coupling to ipRGCs.…”

“…A recent study in rat retina found that all ON sustained wide-field displaced ACs are electrically coupled to ipRGCs (Reifler et al, 2015). The RACs we identify among the labeled Rbp4-Cre cells are similar morphologically to these rat ACs, so we suspected that RACs might have similar functional properties.…”

“…We used tracer coupling to test the hypothesis that the melanopsin-like response seen in RACs is attributable to gap junctional coupling to ipRGCs (Reifler et al, 2015). In Rbp4-Cre;Ai14 mice, two fluorescently tagged RACs were injected with Neurobiotin, which passes through gap junctions to label coupled cells.…”

“…However, recent work has identified several “centrifugal” outputs, through which ipRGC signals are injected back into retinal networks. ipRGCs make both chemical and gap junctional contacts with other retinal neurons (Zhang et al, 2004; Zhang et al, 2007; Zhang et al, 2008; Müller et al, 2010; Reifler et al, 2015; Arroyo et al, 2016; Prigge et al, 2016) and ocular structures (Semo et al, 2014). They influence spontaneous retinal waves (Renna et al, 2011; Kirkby and Feller, 2013) and perinatal vascular development of the eye (Rao et al, 2013).…”

“…They influence spontaneous retinal waves (Renna et al, 2011; Kirkby and Feller, 2013) and perinatal vascular development of the eye (Rao et al, 2013). Electrical coupling permits ipRGCs to inject excitatory currents into all ON displaced wide-field ACs (Reifler et al, 2015). Here, we demonstrate that in Rbp4-Cre mice, these ACs are tagged with enough selectivity to permit morphologic reconstruction, targeted patch recordings, and tracer-coupling studies.…”