Functional properties of spontaneous excitatory currents and encoding of light/dark transitions in horizontal cells of the mouse retina

2015 ◽  
Vol 42 (9) ◽  
pp. 2615-2632 ◽  
Author(s):  
Andreas Feigenspan ◽  
Norbert Babai
Keyword(s):  
Functional Properties ◽  
Horizontal Cells ◽  
Mouse Retina

Unique functional properties of the APB sensitive and insensitive rod pathways signaling light decrements in mouse retinal ganglion cells

2006 ◽  
Vol 23 (1) ◽  
pp. 127-135 ◽  
Author(s):  
GUO-YONG WANG
Keyword(s):  
Functional Properties ◽  
Ganglion Cells ◽  
Amacrine Cells ◽  
Bipolar Cells ◽  
Mouse Retina ◽  
Clear Cut ◽  
Types Of Information ◽  
Rod Bipolar Cells ◽  
Rod Pathway ◽  
Cone Bipolar Cells

Light decrements are mediated by two distinct groups of rod pathways in the dark-adapted retina that can be differentiated on the basis of their sensitivity to the glutamate agonist DL-2-amino-phosphonobutyric (APB). By means of the APB sensitive pathway, rods transmit light decrementsviarod bipolar cells to AII amacrine cells, then to Off cone bipolar cells, which in turn innervate the dendrites of Off ganglion cells. APB hyperpolarizes rod bipolar cells, thus blocking this rod pathway. With APB insensitive pathways, rods either directly synapse onto Off cone bipolar cells, or rods pass light decrement signal to cones by gap junctions. In the present study, whole-cell patch-clamp recordings were made from ganglion cells in the dark-adapted mouse retina to investigate the functional properties of APB sensitive and insensitive rod pathways. The results revealed several clear-cut differences between the APB sensitive and APB insensitive rod pathways. The latency of Off responses to a flashing spot of light was significantly shorter for the APB insensitive pathways than those for the APB sensitive pathway. Moreover, Off responses of the APB insensitive pathways were found to be capable of following substantially higher stimulus frequencies. Nitric oxide was found to selectively block Off responses in the APB sensitive rod pathway. Collectively, these results provide evidence that the APB sensitive and insensitive rod pathways can convey different types of information signaling light decrements in the dark-adapted retina.

scholarly journals Local signals in mouse horizontal cell dendrites

2017 ◽  
Author(s):  
Camille A. Chapot ◽  
Christian Behrens ◽  
Luke E. Rogerson ◽  
Tom Baden ◽  
Sinziana Pop ◽  
...  
Keyword(s):  
Glutamate Release ◽  
Horizontal Cell ◽  
Horizontal Cells ◽  
Single Type ◽  
Mouse Retina ◽  
Gabaergic Interneuron ◽  
List Type ◽  
Cone Photoreceptor ◽  
Cone Photoreceptors ◽  
Temporal Properties

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.

Electrophysiological Properties of Mouse Horizontal Cell GABAA Receptors

2004 ◽  
Vol 92 (5) ◽  
pp. 2789-2801 ◽  
Author(s):  
Andreas Feigenspan ◽  
Reto Weiler
Keyword(s):  
Single Channel ◽  
Horizontal Cell ◽  
Chloride Ions ◽  
Horizontal Cells ◽  
Hill Coefficient ◽  
Mouse Retina ◽  
Patch Clamp Technique ◽  
Open Probability ◽  
Steady State Current ◽  
Single Channel Currents

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%.

scholarly journals Ptf1a is essential for the differentiation of GABAergic and glycinergic amacrine cells and horizontal cells in the mouse retina

Development ◽  
2007 ◽  
Vol 134 (6) ◽  
pp. 1151-1160 ◽  
Author(s):  
H. Nakhai ◽  
S. Sel ◽  
J. Favor ◽  
L. Mendoza-Torres ◽  
F. Paulsen ◽  
...  
Keyword(s):  
Amacrine Cells ◽  
Horizontal Cells ◽  
Mouse Retina

scholarly journals Dopamine D1 receptor modulation of calcium channel currents in horizontal cells of mouse retina

2016 ◽  
Vol 116 (2) ◽  
pp. 686-697 ◽  
Author(s):  
Xue Liu ◽  
James C. R. Grove ◽  
Arlene A. Hirano ◽  
Nicholas C. Brecha ◽  
Steven Barnes
Keyword(s):  
Steady State ◽  
Calcium Channel ◽  
Horizontal Cell ◽  
D1 Receptor ◽  
Horizontal Cells ◽  
Mouse Retina ◽  
Ca Channel ◽  
Transgenic Mouse Line ◽  
Receptor Modulation ◽  
Channel Currents

Horizontal cells form the first laterally interacting network of inhibitory interneurons in the retina. Dopamine released onto horizontal cells under photic and circadian control modulates horizontal cell function. Using isolated, identified horizontal cells from a connexin-57-iCre × ROSA26-tdTomato transgenic mouse line, we investigated dopaminergic modulation of calcium channel currents ( ICa) with whole cell patch-clamp techniques. Dopamine (10 μM) blocked 27% of steady-state ICa, an action blunted to 9% in the presence of the L-type Ca channel blocker verapamil (50 μM). The dopamine type 1 receptor (D1R) agonist SKF38393 (20 μM) inhibited ICa by 24%. The D1R antagonist SCH23390 (20 μM) reduced dopamine and SKF38393 inhibition. Dopamine slowed ICa activation, blocking ICa by 38% early in a voltage step. Enhanced early inhibition of ICa was eliminated by applying voltage prepulses to +120 mV for 100 ms, increasing ICa by 31% and 11% for early and steady-state currents, respectively. Voltage-dependent facilitation of ICa and block of dopamine inhibition after preincubation with a Gβγ-blocking peptide suggested involvement of Gβγ proteins in the D1R-mediated modulation. When the G protein activator guanosine 5′- O-(3-thiotriphosphate) (GTPγS) was added intracellularly, ICa was smaller and showed the same slowed kinetics seen during D1R activation. With GTPγS in the pipette, additional block of ICa by dopamine was only 6%. Strong depolarizing voltage prepulses restored the GTPγS-reduced early ICa amplitude by 36% and steady-state ICa amplitude by 3%. These results suggest that dopaminergic inhibition of ICa via D1Rs is primarily mediated through the action of Gβγ proteins in horizontal cells.

scholarly journals Synaptic Remodeling in the Cone Pathway After Early Postnatal Horizontal Cell Ablation

2021 ◽  
Vol 15 ◽  
Author(s):  
Lena Nemitz ◽  
Karin Dedek ◽  
Ulrike Janssen-Bienhold
Keyword(s):  
Synapse Formation ◽  
Outer Nuclear Layer ◽  
Horizontal Cell ◽  
Bipolar Cells ◽  
Horizontal Cells ◽  
Mouse Retina ◽  
Retina Development ◽  
Synaptic Remodeling ◽  
Cell Ablation ◽  
Cone Pathway

The first synapse of the visual pathway is formed by photoreceptors, horizontal cells and bipolar cells. While ON bipolar cells invaginate into the photoreceptor terminal and form synaptic triads together with invaginating horizontal cell processes, OFF bipolar cells make flat contacts at the base of the terminal. When horizontal cells are ablated during retina development, no invaginating synapses are formed in rod photoreceptors. However, how cone photoreceptors and their synaptic connections with bipolar cells react to this insult, is unclear so far. To answer this question, we specifically ablated horizontal cells from the developing mouse retina. Following ablation around postnatal day 4 (P4)/P5, cones initially exhibited a normal morphology and formed flat contacts with OFF bipolar cells, but only few invaginating contacts with ON bipolar cells. From P15 on, synaptic remodeling became obvious with clustering of cone terminals and mislocalized cone somata in the OPL. Adult cones (P56) finally displayed highly branched axons with numerous terminals which contained ribbons and vesicular glutamate transporters. Furthermore, type 3a, 3b, and 4 OFF bipolar cell dendrites sprouted into the outer nuclear layer and even expressed glutamate receptors at the base of newly formed cone terminals. These results indicate that cones may be able to form new synapses with OFF bipolar cells in adult mice. In contrast, cone terminals lost their invaginating contacts with ON bipolar cells, highlighting the importance of horizontal cells for synapse maintenance. Taken together, our data demonstrate that early postnatal horizontal cell ablation leads to differential remodeling in the cone pathway: whereas synapses between cones and ON bipolar cells were lost, new putative synapses were established between cones and OFF bipolar cells. These results suggest that synapse formation and maintenance are regulated very differently between flat and invaginating contacts at cone terminals.

Functional expression of connexin57 in horizontal cells of the mouse retina

2004 ◽  
Vol 19 (10) ◽  
pp. 2633-2640 ◽  
Author(s):  
Sonja Hombach ◽  
Ulrike Janssen-Bienhold ◽  
Goran Sohl ◽  
Timm Schubert ◽  
Heinrich Bussow ◽  
...  
Keyword(s):  
Functional Expression ◽  
Horizontal Cells ◽  
Mouse Retina
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