Pkcα is essential for the proper activation and termination of rod bipolar cell response

Abstract

PURPOSE. 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. © Association for Research in Vision and Ophthalmology.