Purpose: NiCl(2) (15 microM) enhances the ERG b-wave amplitude of vertebrate retina, up to 1.5-fold by blocking E/R-type voltage-gated Ca(2+) channels, which is mediated by blocking the release of GABA onto ionotropic GABA-A and GABA-C receptors. In vivo, it is likely that zinc, rather than nickel ions, may be involved in the modulation of retinal signalling. Therefore, we tested the effect of both, ZnCl(2) (10 to 500 microM) and DEDTC (100 to 500 microM), which chelates zinc ions for the capacity to influence the ERG b-wave amplitude.
Methods: Transretinal potentials from the isolated bovine retina were recorded as electroretinograms and Ca(2+) inward currents by patch-clamp recordings of stably Ca(v)2.3 transfected HEK-293 cells, yielding an IC(50) value of 5.3 microM for ZnCl(2).
Results: ZnCl(2) (10-15 microM) increased the b-wave amplitude by 1.52-fold +/- 0.12 (n = 6 retinas), which was partially reversible upon washout. The same 1.5-fold stimulation of the b-wave amplitude was reported recently for 15 microM NiCl(2). The superfusion of isolated retinas by DEDTC (100 microM) caused a transient decrease of the ERG b-wave amplitude (0.75-fold +/- 0.06; n = 4), suggesting that the co-secretion of Zn(2+) ions may occur under scotopic conditions.
Conclusion: The stimulatory effect of ZnCl(2) on the ERG b-wave amplitude resembles the stimulatory effect of NiCl(2) and may be mediated rather by the NiCl(2)-sensitive, Ca(v)2.3 E-/R-type voltage-gated Ca(2+) channels than by NiCl(2)-sensitive T-type channels.
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http://dx.doi.org/10.3109/02713680903509410 | DOI Listing |
Front Med (Lausanne)
December 2024
TowardPi Medical Technology Beijing, Beijing, China.
This study aims to investigate the protective effects of docosahexaenoic acid (DHA) combined with bilberry extract (BE) on myopic guinea pigs. In total, 105 healthy pigmented guinea pigs aged 2 weeks were selected and randomly divided into five groups. The normal control (NC) group received no treatment, while the experimental groups wore -6.
View Article and Find Full Text PDFIn Vivo
December 2024
Laboratory of Veterinary Ophthalmology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Republic for Korea
Background/aim: Diabetic retinopathy (DR), a complication of diabetes, causes damage to retinal blood vessels and can lead to vision impairment. Persistent high blood glucose levels contribute to this damage, and despite ongoing research, effective treatment options for DR remain limited. Dimethyl sulfoxide (DMSO) has shown anti-inflammatory and antioxidant properties in both in vivo and in vitro studies; however, its potential as an anti-inflammatory agent in the context of DR has not yet been explored.
View Article and Find Full Text PDFInvest Ophthalmol Vis Sci
December 2024
Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois, United States.
Purpose: The retina contains the highest concentration of the omega 3 fatty acid, docosahexaenoic acid (DHA), in the body. Although epidemiologic studies showed an inverse correlation between the consumption of omega 3 fatty acids and the prevalence of diabetic retinopathy, there are no data showing the effect of diabetes on retinal DHA in humans. In this study, we measured the DHA content of the retina in diabetic and non-diabetic humans as well as mice and determined the effect of diabetes on retinal thickness and function in mice.
View Article and Find Full Text PDFDoc Ophthalmol
December 2024
Behavioural and Brain Sciences Unit, Population Policy and Practice Programme, UCL Great Ormond Street Institute of Child Health, University College London, London, UK.
Purpose: To explore changes in the electroretinogram (ERG) following methylphenidate use in attention-deficit/hyperactivity disorder (ADHD).
Methods: Light adapted ERGs were recorded in five individuals (3 male and 2 female, age range 13.6-21.
Front Neurosci
November 2024
Department of Psychiatry and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
Background: Electroretinograms (ERG) are usually recorded with non-invasive corneal electrodes, requiring direct contact with the ocular surface. However, corneal electrode application is not tolerated by some individuals. The advent of handheld ERG devices has facilitated the use of skin electrodes for ERG measurements.
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