Article
Pharmacological manipulation of oscillatory activity in the retina of the retinitis pigmentosa mouse model rd10
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Published: | November 30, 2017 |
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Objective: To eliminate oscillatory activity that occurs upon photoreceptor degeneration and that may compromise the efficiency of retinal ganglion cell (RGC) stimulation by an electrical prosthesis.
Materials and Methods: Local field potentials (LFP) and spike activity of RGCs were recorded in vitro from retinae of 3–4 months old wildtype (WT) and rd10 mice using multi electrode arrays (MEA). RGCs were stimulated electrically. The effects of different agonists and antagonists at inhibitory neurotransmitter receptors on oscillatory activity were investigated.
Results: In rd10 retinae but not in WT retinae, we observed oscillations in the LFP at a frequency of around 6 Hz. Often oscillations were observed to wax and wane. Blockade of either glycine receptors with strychnine or GABAA-receptors with bicuculline, or the simultaneous blockade of both receptor types changed the frequency of the oscillations, but did not abolish them. In contrast, the agonists glycine and GABA abolished retinal oscillations in a reversible and reproducible way. We found that the efficiency of electrical stimulation – measured as ratio of spike rate before and after the stimulation pulse – was lower in rd10 retina than in WT retina.
Discussion: In rd10 retina, the lower efficiency of electrical stimulation may result from interference of the pathological oscillatory activity with RGC excitability. Future experiments will show whether pharmacological blockade of oscillatory activity will improve stimulation efficiency in rd10 retina.
Acknowledgement: The study was supported by the DFG grants MU-3036/3-3, WA-1472/6-3, JO-1263/1-3.