The influence of lipid peroxidation (LPO) in isolated frog retina on dark adaptation of photoreceptors was studied. Stimulus-response functions, late receptor potential (LRP) as function of the stimulus light intensity were measured before bleach and in a steady state after dark adaptation. It was shown that accumulation of LPO products influenced dark adaptation in photoreceptors. Based on the displacements of the stimulus-response curves and experimental measurement data on the rate of LRP collapse after retina treatment with strophanthin it is concluded that the most probable mechanism of such an influence lies in a change of photoreceptor plasma membrane permeability.
Download full-text PDF |
Source |
---|
Open Biol
January 2025
Institute of Physical Chemistry, Polish Academy of Sciences , Warsaw, Poland.
The vertebrate visual cycle hinges on enzymatically converting all--retinol (at-ROL) into 11--retinal (11c-RAL), the chromophore that binds to opsins in photoreceptors, forming light-responsive pigments. When struck by a photon, these pigments activate the phototransduction pathway and initiate the process of vision. The enzymatic isomerization of at-ROL, crucial for restoring the visual pigments and preparing them to receive new light stimuli, relies on various enzymes found in both the photoreceptors and retinal pigment epithelium cells.
View Article and Find Full Text PDFBackground/objectives: Adaptive optics ophthalmoscopy (AOO) has the potential to provide insights into AMD pathology and to assess the risk of progression. We aim to utilise AOO to describe detailed features of intermediate AMD and to characterise microscopic changes during atrophy development.
Subjects/methods: Patients with intermediate AMD were recruited into PINNACLE, a prospective observational cohort study.
Acta Ophthalmol
January 2025
Harvard University, Boston, Cambridge, USA.
Purpose: There is evidence of the role of dark adaptation (DA) as a functional biomarker in age-related macular degeneration (AMD) where foveal cones are impacted during the initial stages of AMD. In this study we determine the repeatability of smartphone application (MOBILE DA) to evaluate the cone-mediated dark adaptation (DA) in healthy young adults.
Methods: Testing was done by placing a smartphone in front of the subject in a dark room.
Stem Cell Reports
January 2025
Research Center, Kobe City Eye Hospital, Kobe, Hyogo 650-0047, Japan; Research Organization of Science and Technology, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan; Laboratory for Animal Resources and Genetic Engineering, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan. Electronic address:
We have previously shown that the transplantation of stem cell-derived retinal organoid (RO) sheets into animal models of end-stage retinal degeneration can lead to host-graft synaptic connectivity and restoration of vision, which was further improved using genome-edited Islet1 ROs (gROs) with a reduced number of ON-bipolar cells. However, the details of visual function restoration using this regenerative therapeutic approach have not yet been characterized. Here, we evaluated the electrophysiological properties of end-stage rd1 retinas after transplantation (TP-rd1) and compared them with those of wild-type (WT) retinas using multi-electrode arrays.
View Article and Find Full Text PDFAsia Pac J Ophthalmol (Phila)
January 2025
Rescue, Repair and Regeneration Theme, UCL Institute of Ophthalmology, London, United Kingdom. Electronic address:
Purpose: Recovery rate of rod photoreceptor sensitivity (S2 gradient) following a bleach is reduced in age-related macular degeneration (AMD) due to diminished delivery of retinol across a grossly altered Bruch's membrane. Since triterpenoid saponins are known to improve transport across Bruch's, we have assessed their possible use for reversing the visual deficits in AMD.
Design: Double-blind, placebo controlled randomised clinical trial.
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!