Basic research and clinical aspects of the oscillatory potentials of the electroretinogram

Wachtmeister, Lillemor

doi:10.1007/bf00145232

Cited by 86 publications

(66 citation statements)

References 42 publications

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“…In this study, we observed a diabetes-induced increase in OP latency, and topically applied Nepafenac inhibited the increased OP latency despite persistent hyperglycemia. It is widely accepted that the OPs primarily originate from the amacrine cell layer, although some have observed a possible ganglion cell contribution in certain species (46,47). More detailed analysis is needed to discern if Nepafenac treatment directly affects amacrine cell function in diabetes.…”

Section: Discussionmentioning

confidence: 99%

Topical Administration of Nepafenac Inhibits Diabetes-Induced Retinal Microvascular Disease and Underlying Abnormalities of Retinal Metabolism and Physiology

et al. 2007

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Pharmacologic treatment of diabetic retinopathy via eyedrops could have advantages but has not been successful to date. We explored the effect of topical Nepafenac, an anti-inflammatory drug known to reach the retina when administered via eyedrops, on the development of early stages of diabetic retinopathy and on metabolic and physiologic abnormalities that contribute to the retinal disease. Streptozotocin-induced diabetic rats were assigned to three groups (0.3% Nepafenac eyedrops, vehicle eyedrops, and untreated control) for comparison to age-matched nondiabetic control animals. Eyedrops were administered in both eyes four times per day for 2 and 9 months. At 2 months of diabetes, insulin-deficient diabetic control rats exhibited significant increases in retinal prostaglandin E 2 , superoxide, vascular endothelial growth factor (VEGF), nitric oxide (NO), cyclooxygenase-2, and leukostasis within retinal microvessels. All of these abnormalities except NO and VEGF were significantly inhibited by Nepafenac. At 9 months of diabetes, a significant increase in the number of transferase-mediated dUTP nick-end labeling-positive capillary cells, acellular capillaries, and pericyte ghosts were measured in control diabetic rats versus nondiabetic controls, and topical Nepafenac significantly inhibited all of these abnormalities (all P < 0.05). Diabetes-induced activation of caspase-3 and -6 in retina was partially inhibited by Nepafenac (all P < 0.05). Oscillatory potential latency was the only abnormality of retinal function reproducibly detected in these diabetic animals, and Nepafenac significantly inhibited this defect (P < 0.05). Nepafenac did not have a significant effect on diabetes-induced loss of cells in the ganglion cell layer or in corneal protease activity. Topical ocular administration of Nepafenac achieved sufficient drug delivery to the retina and diabetes-induced alterations in retinal vascular metabolism, function, and morphology were inhibited. In contrast, little or no effect was observed on diabetes-induced alterations in retinal ganglion cell survival. Local inhibition of inflammatory pathways in the eye offers a novel therapeutic approach toward inhibiting the development of lesions of diabetic retinopathy.

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Section: Discussionmentioning

confidence: 99%

Topical Administration of Nepafenac Inhibits Diabetes-Induced Retinal Microvascular Disease and Underlying Abnormalities of Retinal Metabolism and Physiology

et al. 2007

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“…Therefore, the OP score behavior, besides specifying a more sensitive ERG pa rameter to differentiate the two rat strains, could hypothetically imply that the structure responsible for OP generation is involved very early in the progressive retinal deteriora tion in the WAG/Rij rats. On the basis of experimental studies also performed on the primate retina, the generation of OPs could involve the bipolar, the amacrine and/or the interplexiform cells [9,10]. In any case, the OPs should represent the activity of inhibi tory feedback circuits of the inner plexiform layer.…”

Section: Discussionmentioning

confidence: 99%

Electroretinographic Response in WAG/Rij Rats after Low-Intensity Cyclic Light Exposure

Cillino¹,

Guarneri²,

Guarneri

et al. 1993

Ophthalmic Res

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In order to investigate the combined influence of age and light, the b-wave and oscillatory potentials (OPs) of the electroretinogram (ERG) were recorded in 1.5-, 7- and 12-month-old WAG/Rij rats, reared under homogenous low-intensity cyclic light exposure. Wistar albino rats of the same ages, reared under the same conditions, served as controls. The b-wave amplitude decreased, and its implicit time increased in the older age groups significantly more in WAG/Rij than in Wistar rats. Statistical analysis indicated that the b-wave amplitude is a more suitable parameter than implicit time in differentiating the ERG variations of one rat strain from the other. The added amplitude of the OPs also decreased in older age groups, but differently from the b wave. This occurred in WAG/Rij rats already at 1.5 months of age.

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“…1990. ing with the normal synaptic/nonsynaptic neural func tions at different retinal or brain structures/subsystems [Grant. 1974: François andDe Rouck, 1978;Shagass and Straumanis, 1978: Bodis-Wollner et al, 1982, 1986aWachtmeister, 1987;Sannita, 1991], The evidence de-rives from clinical experience as well as from experimen tal approaches ranging from humans to animals, to in vitro models. The available knowledge about the physiol ogy of the visual system and the basic pharmacology of the retina, as well as the possibility of attributing electrophysiological changes to functional subsystems by relying on the response to the physical characteristics of the stim ulus (e.g.…”

Section: Introductionmentioning

confidence: 99%

Placebo Effects in Standard Human IMeuropharmacological Studies: Effects of Physiological Variations of Blood Glucose and Ammonia Concentration on the Electro-physiology of the Visual System

Sannita

Balestra²,

DiBon³

et al. 1992

Neuropsychobiology

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The effects on retinal and cortical visual evoked phenomena of the stimulus intensity/spatial frequency and of the spontaneous, physiological blood glucose/ammonia fluctuations were investigated comparatively in a pilot study on young male volunteers. Flash ERG and flash OPs to 5 different stimulus intensities and pattern VECP to 3 spatial frequencies were recorded at 2-hour intervals during a standard acute pharmaco-EEG experimental session (8 h) with administration of placebo; glucose and ammonia blood concentration levels were assessed concomitantly. The effects of the stimulus intensity/spatial frequency were statistically defined for each amplitude/latency measure by nonlinear regression analysis and were removed by computing the residuals from the regression function, which were then tested separately versus the glucose/ammonia concentration by linear regression. Glucose/ammonia statistically significant effects on the visual system were detected at concentration levels within the range of normality and were representative of a nonnegligeable portion of the data overall variance. These effects were selective on retinal/cortical evoked phenomena and it is conceivable that physiological or pathological metabolic changes might account for a still underestimated source of individual variability in human neuropharmacological studies otherwise adequately controlled.

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Basic research and clinical aspects of the oscillatory potentials of the electroretinogram

Cited by 86 publications

References 42 publications

Topical Administration of Nepafenac Inhibits Diabetes-Induced Retinal Microvascular Disease and Underlying Abnormalities of Retinal Metabolism and Physiology

Topical Administration of Nepafenac Inhibits Diabetes-Induced Retinal Microvascular Disease and Underlying Abnormalities of Retinal Metabolism and Physiology

Electroretinographic Response in WAG/Rij Rats after Low-Intensity Cyclic Light Exposure

Placebo Effects in Standard Human IMeuropharmacological Studies: Effects of Physiological Variations of Blood Glucose and Ammonia Concentration on the Electro-physiology of the Visual System

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