In the mouse retina, dopaminergic amacrine (DA) cells synthesize both dopamine and GABA. Both transmitters are released extrasynaptically and act on neighbouring and distant retinal neurons by volume transmission. In simultaneous recordings of dopamine and GABA release from isolated perikarya of DA cells, a proportion of the events of dopamine and GABA exocytosis were simultaneous, suggesting co-release. In addition, DA cells establish GABAergic synapses onto AII amacrine cells, the neurons that transfer rod bipolar signals to cone bipolars. GABAA but not dopamine receptors are clustered in the postsynaptic membrane. Therefore, dopamine, irrespective of its site of release-synaptic or extrasynaptic-exclusively acts by volume transmission. Dopamine is released upon illumination and sets the gain of retinal neurons for vision in bright light. The GABA released at DA cells' synapses probably prevents signals from the saturated rods from entering the cone pathway when the dark-adapted retina is exposed to bright illumination. The GABA released extrasynaptically by DA and other amacrine cells may set a 'GABAergic tone' in the inner plexiform layer and thus counteract the effects of a spillover of glutamate released at the bipolar cell synapses of adjacent OFF and ON strata, thus preserving segregation of signals between ON and OFF pathways.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4455755 | PMC |
| http://dx.doi.org/10.1098/rstb.2014.0186 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Modelling neurodegeneration and inflammation in early diabetic retinopathy using 3D human retinal organoids.
In Vitro Model
February 2024
iNOVA4Health, NOVA Medical School|Faculdade de Ciências Médicas, NMS|FCM, Universidade Nova de Lisboa, Rua Camara Pestana, 6, Lisbon, Portugal.
Purpose: Diabetic retinopathy (DR) is a complication of diabetes and a primary cause of visual impairment amongst working-age individuals. DR is a degenerative condition in which hyperglycaemia results in morphological and functional changes in certain retinal cells. Existing treatments mainly address the advanced stages of the disease, which involve vascular defects or neovascularization.
View Article and Find Full Text PDFD e h ydro d olichyl d iphosphate s ynthase (DHDDS) is an essential enzyme required for several forms of protein glycosylation in all eukaryotic cells. Surprisingly, three mutant alleles, ( (K42E/K42E), (T206A/K42E), and found in only one patient, (R98W/K42E) have been reported that cause non-syndromic retinitis pigmentosa (RP59), an inherited retinal degeneration (IRD). Because T206A was only observed heterozygously with the K42E allele in RP59 patients, we used CRISPR/CAS9 technology to generate T206A/T206A, and subsequently T206A/K42E alleles in mice to assess the contribution of the T206A allele to the disease phenotype, to model the human disease, and to compare resulting phenotypes to our homozygous K42E mouse model.
View Article and Find Full Text PDFVirtual Human Retina: Simulating Neural Signalling, Degeneration, and Responses to Electrical Stimulation.
Brain Stimul
January 2025
Graduate School of Biomedical Engineering, UNSW, Sydney, NSW 2052, Australia; Tyree Foundation Institute of Health Engineering (IHealthE), UNSW, Sydney, NSW 2052, Australia. Electronic address:
Introduction: Current brain-based visual prostheses pose significant challenges impeding adoption such as the necessarily complex surgeries and occurrence of more substantial side effects due to the sensitivity of the brain. This has led to much effort toward vision restoration being focused on the more approachable part of the brain - the retina. Here we introduce a novel, parameterized simulation platform that enables study of human retinal degeneration and optimization of stimulation strategies.
View Article and Find Full Text PDFCapacitance Measurements of Exocytosis From AII Amacrine Cells in Retinal Slices.
Bio Protoc
January 2025
Department of Biomedicine, University of Bergen, Bergen, Norway.
During neuronal synaptic transmission, the exocytotic release of neurotransmitters from synaptic vesicles in the presynaptic neuron evokes a change in conductance for one or more types of ligand-gated ion channels in the postsynaptic neuron. The standard method of investigation uses electrophysiological recordings of the postsynaptic response. However, electrophysiological recordings can directly quantify the presynaptic release of neurotransmitters with high temporal resolution by measuring the membrane capacitance before and after exocytosis, as fusion of the membrane of presynaptic vesicles with the plasma membrane increases the total capacitance.
View Article and Find Full Text PDFRetinal ganglion cells encode the direction of motion outside their classical receptive field.
Proc Natl Acad Sci U S A
January 2025
Department of Brain Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel.
Retinal ganglion cells (RGCs) typically respond to light stimulation over their spatially restricted receptive field. Using large-scale recordings in the mouse retina, we show that a subset of non- direction-selective (DS) RGCs exhibit asymmetric activity, selective to motion direction, in response to a stimulus crossing an area far beyond the classic receptive field. The extraclassical response arises via inputs from an asymmetric distal zone and is enhanced by desensitization mechanisms and an inherent DS component, creating a network of neurons responding to motion toward the optic disc.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!