Diminished vision in healthy aging is associated with increased retinal L-type voltage gated calcium channel ion influx.
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ABSTRACT: Extensive evidence implicates an increase in hippocampal L-type voltage-gated calcium channel (L-VGCC) expression, and ion influx through these channels, in age-related cognitive declines. Here, we ask if this "calcium hypothesis" applies to the neuroretina: Is increased influx via L-VGCCs related to the well-documented but poorly-understood vision declines in healthy aging? In Long-Evans rats we find a significant age-related increase in ion flux through retinal L-VGCCs in vivo (manganese-enhanced MRI (MEMRI)) that are longitudinally linked with progressive vision declines (optokinetic tracking). Importantly, the degree of retinal Mn(2+) uptake early in adulthood significantly predicted later visual contrast sensitivity declines. Furthermore, as in the aging hippocampus, retinal expression of a drug-insensitive L-VGCC isoform (α1D) increased - a pattern confirmed in vivo by an age-related decline in sensitivity to L-VGCC blockade. These data highlight mechanistic similarities between retinal and hippocampal aging, and raise the possibility of new treatment targets for minimizing vision loss during healthy aging.
SUBMITTER: Bissig D
PROVIDER: S-EPMC3572962 | biostudies-literature |
REPOSITORIES: biostudies-literature
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