Age-related decrease of potassium currents in glial (Müller) cells of the human retina.
BACKGROUND
Age-dependent alterations have been investigated far less in retinal glial cells than in retinal neurons. We investigated age-dependent alterations of inwardly rectifying potassium (Kir) currents in Müller glial cells of the human retina.


METHODS
Müller cells were isolated immediately post mortem from donors without a reported history of eye disease, and the amplitudes of Kir currents and of currents through high-voltage-activated (HVA) calcium channels were measured by whole-cell patch clamping.


RESULTS
The amplitude of the Kir currents was lower in the cells from donors older than 50 years than in the cells of younger donors; the decrease was strongly correlated with the donor's age (p < 0.001). The current amplitude in the cells from donors older than 60 years was about 40% lower than the amplitude in the cells from donors younger than 50 years. The amplitude of the HVA currents was greater in the cells from donors older than 55 years than in the cells from younger donors; the increase, up to about 500%, was strongly age-dependent (p < 0.001).


CONCLUSIONS
The age-related decrease in Kir-current amplitude in Müller cells may reflect the neuron loss in the aged retina. Our findings also indicate that retinal glial cells have enhanced cytoplasmic calcium signals in the course of aging.
Bringmann
Andreas
A
Department of Ophthalmology, Eye Clinic, University of Leipzig, Medical Faculty, Leipzig, Germany. bria@medizin.uni-leipzig.de
Kohen
Leon
L
Wolf
Sebastian
S
Wiedemann
Peter
P
Reichenbach
Andreas
A
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D015220:Calcium Channels / Q000378:metabolism; D006801:Humans; D008875:Middle Aged; D009457:Neuroglia / Q000502:physiology*; D018408:Patch-Clamp Techniques; D011188:Potassium / Q000378:metabolism*; D024661:Potassium Channels, Inwardly Rectifying / Q000378:metabolism*; D012160:Retina / Q000502:physiology*
D015220:Calcium Channels; D024661:Potassium Channels, Inwardly Rectifying; D011188:Potassium