Light-evoked lateral GABAergic inhibition at single bipolar cell synaptic terminals is driven by distinct retinal microcircuits
| Autor: | Jozsef Vigh, Evan Vickers, Henrique von Gersdorff |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2011 |
| Předmět: |
Cyclopropanes
Male Retinal Bipolar Cells Patch-Clamp Techniques Light Carboxylic Acids Presynaptic Terminals Tetrodotoxin Biology In Vitro Techniques Inhibitory postsynaptic potential Article Retina Statistics Nonparametric GABA Antagonists chemistry.chemical_compound Glutamatergic Goldfish Quinoxalines medicine Animals Drug Interactions Photoreceptor Cells Patch clamp gamma-Aminobutyric Acid Feedback Physiological Analysis of Variance Dose-Response Relationship Drug General Neuroscience Sodium channel Retinal Neural Inhibition Electric Stimulation Pyridazines Light intensity medicine.anatomical_structure chemistry Inhibitory Postsynaptic Potentials Pertussis Toxin Excitatory postsynaptic potential Female Propionates Neuroscience Excitatory Amino Acid Antagonists Photic Stimulation Signal Transduction Sodium Channel Blockers |
| Popis: | Inhibitory amacrine cells (ACs) filter visual signals crossing the retina by modulating the excitatory, glutamatergic output of bipolar cells (BCs) on multiple temporal and spatial scales. Reciprocal feedback from ACs provides focal inhibition that is temporally locked to the activity of presynaptic BC activity, whereas lateral feedback originates from ACs excited by distant BCs. These distinct feedback mechanisms permit temporal and spatial computation at BC terminals. Here, we used a unique preparation to study light-evoked IPSCs recorded from axotomized terminals of ON-type mixed rod/cone BCs (Mb) in goldfish retinal slices. In this preparation, light-evoked IPSCs could only reach axotomized BC terminals via the lateral feedback pathway, allowing us to study lateral feedback in the absence of overlapping reciprocal feedback components. We found that light evokes ON and OFF lateral IPSCs (L-IPSCs) in Mb terminals having different temporal patterns and conveyed via distinct retinal pathways. The relative contribution of rods versus cones to ON and OFF L-IPSCs was light intensity dependent. ACs presynaptic to Mb BC terminals received inputs via AMPA/KA- and NMDA-type receptors in both the ON and OFF pathways, and used TTX-sensitive sodium channels to boost signal transfer along their processes. ON and OFF L-IPSCs, like reciprocal feedback IPSCs, were mediated by both GABAAand GABACreceptors. However, our results suggest that lateral and reciprocal feedback do not cross-depress each other, and are therefore mediated by distinct populations of ACs. These findings demonstrate that retinal inhibitory circuits are highly specialized to modulate BC output at different light intensities. |
| Databáze: | OpenAIRE |
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