PKC{alpha} is essential for the proper activation and termination of rod bipolar cell response.
OBJECTIVE
Protein kinase (PKC)-α is abundant in retinal bipolar cells. This study was performed to explore its role in visual processing.


METHODS
PKCα-knockout (Prkca(-/-)) mice and control animals were examined by using electroretinography (ERG), light microscopy, and immunocytochemistry.


RESULTS
The Prkca(-/-) mice showed no signs of retinal degeneration up to 12 months of age, but ERG measurements indicated a decelerated increase in the ascending limb of the scotopic (rod-sensitive) b-wave as well as a delayed return to baseline. These results suggest that PKCα is an important modulator that affects bipolar cell signal transduction and termination. Confocal microscopy of retinal sections showed that PKCα co-localized with calbindin, which indicates a PKCα localization in close proximity to the horizontal cell terminals. In addition, the implicit time of the ERG c-wave originating from the retinal pigment epithelium (RPE) and the recovery of photoreceptors from bleaching conditions were substantially faster in the knockout mice than in the wild-type control animals.


CONCLUSIONS
These results suggest that PKCα is a modulator of rod-bipolar cell function by accelerating glutamate-driven signal transduction and termination. This modulation is of importance in the switch between scotopic and photopic vision. Furthermore, PKCα seems to play a role in RPE function.
Ruether
Klaus
K
Charité- Eye-Hospital, Campus Virchow-Klinikum, Universitätsmedizin Berlin, Berlin, Germany. ruether@freenet.de
Feigenspan
Andreas
A
Pirngruber
Judith
J
Leitges
Michael
M
Baehr
Wolfgang
W
Strauss
Olaf
O
D000818:Animals; D015139:Blotting, Southern; D003623:Dark Adaptation; D004596:Electroretinography; D005260:Female; D005838:Genotype; D007150:Immunohistochemistry; D008027:Light; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008853:Microscopy; D016133:Polymerase Chain Reaction; D051571:Protein Kinase C-alpha / Q000502:physiology*; D051245:Retinal Bipolar Cells / Q000201:enzymology* / Q000528:radiation effects; D017948:Retinal Rod Photoreceptor Cells / Q000201:enzymology* / Q000528:radiation effects; D014785:Vision, Ocular / Q000502:physiology*
D051571:Protein Kinase C-alpha