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Direct-Coupled Electroretinogram (DC-ERG) for Recording the Light-Evoked Electrical Responses of the Mouse Retinal Pigment Epithelium
Published on: July 14, 2020
Multifocal electroretinogram in rhodopsin P347L transgenic pigs
Yiu-fai Ng1, Henry H L Chan, Patrick H W Chu
1Laboratory of Experimental Optometry (Neuroscience), School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR, China.
Investigative Ophthalmology & Visual Science
|January 29, 2008
Summary
Neural rewiring in retinitis pigmentosa (RP) alters signal processing. In transgenic pigs, ectopic cone-bipolar cell synapses changed the ON-pathway, modifying inner retinal neuron function.
Area of Science:
- Neuroscience
- Ophthalmology
- Retinal Degeneration
Background:
- Retinitis pigmentosa (RP) involves neural ectopic rewiring, potentially creating aberrant cone-bipolar cell synapses.
- This rewiring can lead to atypical retinal signal processing, impacting visual function.
Purpose of the Study:
- To investigate the sources and nature of altered signal processing in a large animal model of RP.
- To examine multifocal electroretinograms (mfERGs) in rhodopsin P347L transgenic (Tg) pigs.
Main Methods:
- mfERG responses were recorded from a Tg pig before and after drug application (TTX, NMDA, APB, PDA).
- Drug applications helped identify contributions from inner retinal neurons, ON-pathway, OFF-pathway, and photoreceptors.
- Tg mfERG data were compared to age-matched wild-type (WT) control pigs.
Main Results:
- Significant differences were observed in inner retinal response and ON-bipolar cell pathway contributions between Tg and WT pigs.
- Early inner retinal components in Tg mfERGs showed alterations, with inversions around 24 and 40 ms.
- OFF-bipolar cell pathway contributions and cone cell responses remained largely unchanged in Tg pigs.
Conclusions:
- Ectopic synapses between cones and rod bipolar cells in Tg retinas likely altered ON-bipolar cell pathway signal processing.
- Modified visual input from the outer retina resulted in altered signal processing within inner retinal neurons.
