Effects of a metabotropic glutamate 1 receptor antagonist on light responses of retinal ganglion cells in a rat model of retinitis pigmentosa.
BACKGROUND: Retinitis pigmentosa (RP) is a progressive retinal degenerative disease that causes deterioration of rod and cone photoreceptors. A well-studied animal model of RP is the transgenic P23H rat, which carries a mutation in the rhodopsin gene. Previously, I reported that blocking retinal GAB...
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doaj-77bf3ee7e2ff41af9051dfaaee297d742020-11-24T21:50:43ZengPublic Library of Science (PLoS)PLoS ONE1932-62032013-01-01810e7912610.1371/journal.pone.0079126Effects of a metabotropic glutamate 1 receptor antagonist on light responses of retinal ganglion cells in a rat model of retinitis pigmentosa.Ralph J JensenBACKGROUND: Retinitis pigmentosa (RP) is a progressive retinal degenerative disease that causes deterioration of rod and cone photoreceptors. A well-studied animal model of RP is the transgenic P23H rat, which carries a mutation in the rhodopsin gene. Previously, I reported that blocking retinal GABAC receptors in the P23H rat increases light responsiveness of retinal ganglion cells (RGCs). Because activation of metabotropic glutamate 1 (mGlu1) receptors may enhance the release of GABA onto GABAC receptors, I examined the possibility that blocking retinal mGlu1 receptors might in itself increase light responsiveness of RGCs in the P23H rat. METHODOLOGY/PRINCIPAL FINDINGS: Electrical recordings were made from RGCs in isolated P23H rat retinas. Spike activity of RGCs was measured in response to brief flashes of light over a range of light intensities. Intensity-response curves were evaluated prior to and during bath application of the mGlu1 receptor antagonist JNJ16259685. I found that JNJ16259685 increased light sensitivity of all ON-center RGCs and most OFF-center RGCs studied. RGCs that were least sensitive to light showed the greatest JNJ16259685-induced increase in light sensitivity. On average, light sensitivity increased in ON-center RGCs by 0.58 log unit and in OFF-center RGCs by 0.13 log unit. JNJ16259685 increased the maximum peak response of ON-center RGCs by 7% but had no significant effect on the maximum peak response of OFF-center RGCs. The effects of JNJ16259685 on ON-center RGCs were occluded by a GABAC receptor antagonist. CONCLUSIONS: The results of this study indicate that blocking retinal mGlu1 receptors in a rodent model of human RP potentiates transmission of any, weak signals originating from photoreceptors. This augmentation of photoreceptor-mediated signals to RGCs occurs presumably through a reduction in GABAC-mediated inhibition.http://europepmc.org/articles/PMC3810128?pdf=render |
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DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Ralph J Jensen |
spellingShingle |
Ralph J Jensen Effects of a metabotropic glutamate 1 receptor antagonist on light responses of retinal ganglion cells in a rat model of retinitis pigmentosa. PLoS ONE |
author_facet |
Ralph J Jensen |
author_sort |
Ralph J Jensen |
title |
Effects of a metabotropic glutamate 1 receptor antagonist on light responses of retinal ganglion cells in a rat model of retinitis pigmentosa. |
title_short |
Effects of a metabotropic glutamate 1 receptor antagonist on light responses of retinal ganglion cells in a rat model of retinitis pigmentosa. |
title_full |
Effects of a metabotropic glutamate 1 receptor antagonist on light responses of retinal ganglion cells in a rat model of retinitis pigmentosa. |
title_fullStr |
Effects of a metabotropic glutamate 1 receptor antagonist on light responses of retinal ganglion cells in a rat model of retinitis pigmentosa. |
title_full_unstemmed |
Effects of a metabotropic glutamate 1 receptor antagonist on light responses of retinal ganglion cells in a rat model of retinitis pigmentosa. |
title_sort |
effects of a metabotropic glutamate 1 receptor antagonist on light responses of retinal ganglion cells in a rat model of retinitis pigmentosa. |
publisher |
Public Library of Science (PLoS) |
series |
PLoS ONE |
issn |
1932-6203 |
publishDate |
2013-01-01 |
description |
BACKGROUND: Retinitis pigmentosa (RP) is a progressive retinal degenerative disease that causes deterioration of rod and cone photoreceptors. A well-studied animal model of RP is the transgenic P23H rat, which carries a mutation in the rhodopsin gene. Previously, I reported that blocking retinal GABAC receptors in the P23H rat increases light responsiveness of retinal ganglion cells (RGCs). Because activation of metabotropic glutamate 1 (mGlu1) receptors may enhance the release of GABA onto GABAC receptors, I examined the possibility that blocking retinal mGlu1 receptors might in itself increase light responsiveness of RGCs in the P23H rat. METHODOLOGY/PRINCIPAL FINDINGS: Electrical recordings were made from RGCs in isolated P23H rat retinas. Spike activity of RGCs was measured in response to brief flashes of light over a range of light intensities. Intensity-response curves were evaluated prior to and during bath application of the mGlu1 receptor antagonist JNJ16259685. I found that JNJ16259685 increased light sensitivity of all ON-center RGCs and most OFF-center RGCs studied. RGCs that were least sensitive to light showed the greatest JNJ16259685-induced increase in light sensitivity. On average, light sensitivity increased in ON-center RGCs by 0.58 log unit and in OFF-center RGCs by 0.13 log unit. JNJ16259685 increased the maximum peak response of ON-center RGCs by 7% but had no significant effect on the maximum peak response of OFF-center RGCs. The effects of JNJ16259685 on ON-center RGCs were occluded by a GABAC receptor antagonist. CONCLUSIONS: The results of this study indicate that blocking retinal mGlu1 receptors in a rodent model of human RP potentiates transmission of any, weak signals originating from photoreceptors. This augmentation of photoreceptor-mediated signals to RGCs occurs presumably through a reduction in GABAC-mediated inhibition. |
url |
http://europepmc.org/articles/PMC3810128?pdf=render |
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