The slow wave component of retinal activity in rd/rd mice recorded with a multi-electrode array
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Published on: July 14, 2020
1Department of Physiology, Chungbuk National University School of Medicine, Cheongju, 361-763, Korea.
Abstract:
We investigated the differences in the retinal activity between normal and degenerate retina. Multi-electrode recordings were performed in in vitro mice retinas. Only short duration (<2 ms) retinal spikes were recorded in normal mice by postnatal day 28. However, in rd/rd mice, a slow wave component with approximately 100 ms duration was also recorded along with the spikes. We attempted to understand the mechanism of this slow wave component in degenerate retina by applying various synaptic blockers. With CNQX/AP-7, the glutamate antagonist (n = 7), the slow wave component disappeared while the normally less-dominant retinal spikes became more apparent. With strychnine, the glycine antagonist (n = 3) or picrotoxin, GABA antagonist (n = 3), the amplitude of the slow wave component increased. These suggest that a stronger excitatory glutamate input from bipolar cells to ganglion cells is the main contributor to this slow wave component in rd/rd mice.
Insights
Degenerate mouse retinas exhibit a slow wave component in retinal activity, unlike normal retinas. This slow wave is primarily driven by glutamate input from bipolar to ganglion cells.
Area of Science:
- Neuroscience
- Retinal Physiology
- Molecular Biology
Background:
- Retinal degeneration leads to altered neuronal activity.
- Understanding these changes is crucial for developing therapeutic strategies.
Purpose of the Study:
- To investigate the electrophysiological differences between normal and degenerate mouse retinas.
- To elucidate the underlying mechanisms of the slow wave component observed in degenerate retinas.
Main Methods:
- Multi-electrode recordings were performed on in vitro mouse retinas.
- Synaptic blockers (glutamate, glycine, GABA antagonists) were applied to analyze the slow wave component.
Main Results:
- Normal retinas showed only short-duration spikes (<2 ms).
- Degenerate (rd/rd) retinas exhibited both spikes and a slow wave component (~100 ms).
- Glutamate antagonist (CNQX/AP-7) abolished the slow wave, while glycine and GABA antagonists increased its amplitude.
Conclusions:
- The slow wave component in rd/rd mice is mainly caused by enhanced excitatory glutamate input from bipolar cells to ganglion cells.
- This finding provides insights into the pathophysiology of retinal degeneration.
