Current source density analysis of the electroretinographic d wave of frog retina

Xu, Xijing; Karwoski, Chester J.

doi:10.1152/jn.1995.73.6.2459

Cited by 36 publications

(23 citation statements)

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“…More evidence to support the role of CPPG as an mGluR antagonist that affects On-bipolar cells comes from recordings of light-evoked intraretinal field potentials (ERGs) in the intact eyecup. In the ERG, the b wave represents the lightevoked electrical activity of the On-bipolar cells (Stockton and Slaughter, 1989), whereas the d wave reflects activity of Off-bipolar cells (Xu and Karwoski, 1995). The suppression of the b wave and not the d wave by CPPG supports the hypothesis that it specifically disrupts the light responses of On-bipolar cells.…”

Section: Pharmacological Properties Of Ap4-sensitive Mglurs In the Rementioning

confidence: 66%

Origin of Transient and Sustained Responses in Ganglion Cells of the Retina

2000

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Section: Pharmacological Properties Of Ap4-sensitive Mglurs In the Rementioning

confidence: 66%

Origin of Transient and Sustained Responses in Ganglion Cells of the Retina

2000

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“…The ERG d-wave is a population response originating largely from Off BC depolarization triggered at light offset by glutamate release from cones (Xu and Karwoski, 1995;Awatramani et al, 2001). Because the b-wave typically obscures the d-wave after shorter flashes, we bathed the eyecup in 10 µM of the mGluR6 agonist L-AP4 to block the b-wave and isolate the d-wave.…”

Section: Synaptic Filtering By Ca 2+ /Cam-dependent Replenishmentmentioning

confidence: 99%

Calmodulin enhances ribbon replenishment and shapes filtering of synaptic transmission by cone photoreceptors

Hook¹,

Parmelee²,

Chen³

et al. 2014

J Cell Biol

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At the first synapse in the vertebrate visual pathway, light-evoked changes in photoreceptor membrane potential alter the rate of glutamate release onto second-order retinal neurons. This process depends on the synaptic ribbon, a specialized structure found at various sensory synapses, to provide a supply of primed vesicles for release. Calcium (Ca 2+ ) accelerates the replenishment of vesicles at cone ribbon synapses, but the mechanisms underlying this acceleration and its functional implications for vision are unknown. We studied vesicle replenishment using paired whole-cell recordings of cones and postsynaptic neurons in tiger salamander retinas and found that it involves two kinetic mechanisms, the faster of which was diminished by calmodulin (CaM) inhibitors. We developed an analytical model that can be applied to both conventional and ribbon synapses and showed that vesicle resupply is limited by a simple time constant,  = 1/(Ds), where D is the vesicle diffusion coefficient,  is the vesicle diameter,  is the vesicle density, and s is the probability of vesicle attachment. The combination of electrophysiological measurements, modeling, and total internal reflection fluorescence microscopy of single synaptic vesicles suggested that CaM speeds replenishment by enhancing vesicle attachment to the ribbon. Using electroretinogram and whole-cell recordings of light responses, we found that enhanced replenishment improves the ability of cone synapses to signal darkness after brief flashes of light and enhances the amplitude of responses to higherfrequency stimuli. By accelerating the resupply of vesicles to the ribbon, CaM extends the temporal range of synaptic transmission, allowing cones to transmit higher-frequency visual information to downstream neurons. Thus, the ability of the visual system to encode time-varying stimuli is shaped by the dynamics of vesicle replenishment at photoreceptor synaptic ribbons.

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“…It results from electrical activity of the retinal pigment epithelium and Muller cell hyperpolarisation (Frishman 2006;Ekesten 2013). The d-wave is the next positive peak, being a late OFF-type response (Xu and Karwoski 1995). The i-wave is the following positive peak.…”

Section: Essence Of Ergmentioning

confidence: 95%

Electroretinography in dogs: a review

Drazek¹,

Lew²,

Lew³

et al. 2014

Vet. Med. - Czech

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Electroretinography (ERG) in the form of full-field, flash ERG is the most commonly used technique in veterinary ophthalmology for diagnosing the functioning of the outer retina. Under light stimulation spatially distributed different cell types within the retina produce time-varying electric responses. These are recorded in the form of ERG traces consisting of a series of positive and negative wavelets. The possibility of selective stimulation of individual types of retinal cells and the analysis of constituent components of ERGs are the basis for determining the source of abnormalities and diagnosis of various types of dysfunction. In many cases, the ERG allows diagnosis of hereditary retinal disorders in dogs before the appearance of behavioural and ophthalmoscopic symptoms. This review is an introduction to the electrophysiology of vision, intended for small animal practitioners, and aimed at presenting the benefits of ERG for early ophthalmic diagnostics in dogs.Keywords: ERG; ophthalmology; PRA; retina

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Current source density analysis of the electroretinographic d wave of frog retina

Cited by 36 publications

References 0 publications

Origin of Transient and Sustained Responses in Ganglion Cells of the Retina

Origin of Transient and Sustained Responses in Ganglion Cells of the Retina

Calmodulin enhances ribbon replenishment and shapes filtering of synaptic transmission by cone photoreceptors

Electroretinography in dogs: a review

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