Abstract
Purpose:
Retinitis pigmentosa is a neurodegenerative disease and designated by the degeneration of photoreceptors, finally leading to blindness. Analysis of animal models with a genetically caused retinal degeneration, e.g., the retinal dystrophic Royal College of Surgeons (RCS) rat, showed that photoreceptor degeneration induces a remodeling process of remaining neurons. As an effect of this process, the spontaneous spiking activity of retinal ganglion cells (GC) changes. In this study we analyzed in vitro the spontaneous firing activity of GCs in the RCS rat in a time-dependent manner and compared the results with recordings of coeval wild-type control animals.
Methods:
Retinae of RCS rats between postnatal week 2 (2we) and week 30 (30we) were analyzed. As control the activity of isolated wild-type wistar rat retinae was recorded. For detection of GC activity, the isolated whole mount retinae were placed on 8x8 three dimensional multi electrode arrays (3D MEA’s). The raw data were evaluated with different filter settings, e.g. 300 Hz HPF, 50 Hz LPF.
Results:
The spiking activity of the RCS ganglion cells changed during different time-points of retinal degeneration. Within the first weeks the firing rate was similar to the activity of the respective wild-type ganglion cells. In GCs of 15 week-old RCS rats the spontaneous spiking activity was lower than in the first weeks and in the respective control GCs. Our results revealed a decrease in the spiking rate over age in the RCS rat, which was in contrast to the control.
Conclusions:
The decrease in spiking activity during retinal degeneration in RCS rats showed that the photoreceptor loss leads to changes of spontaneous spiking activity in GCs. Furthermore, the changes in RCS GCs activity depended on the stage of retinal degeneration. In further experiments we are going to observe effects of synaptic blockers on electrophysiological properties in RCS rats. This could be an important aspect for the development of new treatments for retinitis pigmentosa.
Keywords: 494 degenerations/dystrophies •
688 retina •
508 electrophysiology: non-clinical