Horizontal cell density and mosaic regularity in pigmented and albino mouse retina

2002 ◽  
Vol 454 (2) ◽  
pp. 168-176 ◽  
Author(s):  
Mary A. Raven ◽  
Benjamin E. Reese

2001 ◽  
Vol 306 (2) ◽  
pp. 341-346 ◽  
Author(s):  
Sung-Jin Park ◽  
In-Beom Kim ◽  
Kyu-Ryong Choi ◽  
Jung-Il Moon ◽  
Su-Ja Oh ◽  
...  


2008 ◽  
Vol 28 (27) ◽  
pp. 6818-6825 ◽  
Author(s):  
J. Trumpler ◽  
K. Dedek ◽  
T. Schubert ◽  
L. P. de Sevilla Muller ◽  
M. Seeliger ◽  
...  


Author(s):  
Michael J. Camerino ◽  
Ian J. Engerbretson ◽  
Parker A. Fife ◽  
Nathan B. Reynolds ◽  
Mikel H. Berria ◽  
...  


2017 ◽  
Author(s):  
Camille A. Chapot ◽  
Christian Behrens ◽  
Luke E. Rogerson ◽  
Tom Baden ◽  
Sinziana Pop ◽  
...  

SummaryThe mouse retina contains a single type of horizontal cell, a GABAergic interneuron that samples from all cone photoreceptors within reach and modulates their glutamatergic output via parallel feedback mechanisms. Because horizontal cells form an electrically-coupled network, they have been implicated in global signal processing, such as large scale contrast enhancement. Recently, it has been proposed that horizontal cells can also act locally at the level of individual cone photoreceptors. To test this possibility physiologically, we used two-photon microscopy to record light stimulus-evoked Ca2+signals in cone axon terminals and horizontal cell dendrites as well as glutamate release in the outer plexiform layer. By selectively stimulating the two mouse cone opsins with green and UV light, we assessed whether signals from individual cones remain “isolated” within horizontal cell dendritic tips, or whether they spread across the dendritic arbour. Consistent with the mouse‘s opsin expression gradient, we found that the Ca2+signals recorded from dendrites of dorsal horizontal cells were dominated by M- and those of ventral horizontal cells by S-opsin activation. The signals measured in neighbouring horizontal cell dendritic tips varied markedly in their chromatic preference, arguing against global processing. Rather, our experimental data and results from biophysically realistic modelling support the idea that horizontal cells can process cone input locally, extending the “classical” view of horizontal cells function. Pharmacologically removing horizontal cells from the circuitry reduced the sensitivity of the cone signal to low frequencies, suggesting that local horizontal cell feedback shapes the temporal properties of cone output.HighlightsLight-evoked Ca2+signals in horizontal cell dendrites reflect opsin gradientChromatic preferences in neighbouring dendritic tips vary markedlyMouse horizontal cells process cone photoreceptor input locallyLocal horizontal cell feedback shapes the temporal properties of cone outputeTOC BlurbChapot et al. show that local light responses in mouse horizontal cell dendrites inherit properties, including chromatic preference, from the presynaptic cone photoreceptor, suggesting that their dendrites can provide “private” feedback to cones, for instance, to shape the temporal filtering properties of the cone synapse.



2004 ◽  
Vol 92 (5) ◽  
pp. 2789-2801 ◽  
Author(s):  
Andreas Feigenspan ◽  
Reto Weiler

GABA-induced currents have been characterized in isolated horizontal cells from lower vertebrates but not in mammalian horizontal cells. Therefore horizontal cells were isolated after enzymatical and mechanical dissociation of the adult mouse retina and visually identified. We recorded from horizontal cell bodies using the whole cell and outside-out configuration of the patch-clamp technique. Extracellular application of GABA induced inward currents carried by chloride ions. GABA-evoked currents were completely and reversibly blocked by the competitive GABAA receptor antagonist bicuculline (IC50 = 1.7 μM), indicating expression of GABAA but not GABAC receptors. Their affinity for GABA was moderate (EC50 = 30 μM), and the Hill coefficient was 1.3, corresponding to two GABA binding sites. GABA responses were partially reduced by picrotoxin with differential effects on peak and steady-state current values. Zinc blocked the GABA response with an IC50 value of 7.3 μM in a noncompetitive manner. Furthermore, GABA receptors of horizontal cells were modulated by extracellular application of diazepam, zolpidem, methyl 6,7-dimethoxy-4-ethyl-β-carboxylate, pentobarbital, and alphaxalone, thus showing typical pharmacological properties of CNS GABAA receptors. GABA-evoked single-channel currents were characterized by a main conductance state of 29.8 pS and two subconductance states (20.2 and 10.8 pS, respectively). Kinetic analysis of single-channel events within bursts revealed similar mean open and closed times for the main conductance and the 20.2-pS subconductance state, resulting in open probabilities of 44.6 and 42.7%, respectively. The ratio of open to closed times, however, was significantly different for the 10.8-pS subconductance state with an open probability of 57.2%.



2014 ◽  
Vol 34 (35) ◽  
pp. 11826-11843 ◽  
Author(s):  
R. Kemmler ◽  
K. Schultz ◽  
K. Dedek ◽  
T. Euler ◽  
T. Schubert


2021 ◽  
Author(s):  
Chi Sun ◽  
Xiaodong Zhang ◽  
Philip Andrew Ruzycki ◽  
Shiming Chen

MLL1 (KMT2A) and MLL2 (KMT2B) are homologous members of the mixed-lineage leukemia (MLL) family of histone methyltransferases involved in epigenomic transcriptional regulation. Their sequence variants have been associated with neurological and psychological disorders, but little is known about their roles and mechanism of action in CNS development. Using mouse retina as a model, we previously reported the roles of MLL1 in retinal neurogenesis and horizontal cell maintenance. Here we determine roles of MLL2 and MLL1/MLL2 together in retinal development using conditional knockout (CKO) mice. Deleting Mll2 from Chx10+ retinal progenitors resulted in a similar phenotype as Mll1 CKO, but removal of both alleles produced much more severe deficits than each single CKO: 1-month double CKO mutants displayed null light responses in electroretinogram; thin retinal layers, including shorter photoreceptor outer segments with impaired phototransduction gene expression; and reduced numbers of M-cones, horizontal and amacrine neurons, followed by fast retinal degeneration. Despite moderately reduced progenitor cell proliferation at P0, the neurogenic capacity was largely maintained in double CKO mutants. However, upregulated apoptosis and reactive gliosis were detected during postnatal retinal development. Finally, the removal of both MLLs in fated rods produced a normal phenotype, but the CKO in M-cones impaired M-cone function and survival, indicating both cell non-autonomous and autonomous mechanisms. Altogether, our results suggest that MLL1/MLL2 play redundant roles in maintaining specific retinal neurons after cell fate specification and are essential for establishing functional neural networks.



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