Diurnal and circadian variation of protein kinase C immunoreactivity in the rat retina.
We studied the dependence of the expression of protein kinase C immunoreactivity (PKC-IR) in the rat retina on the light:dark (LD) cycle and on circadian rhythmicity in complete darkness (DD). Two anti-PKC alpha antibodies were employed: One, which we call PKCalphabeta recognized the hinge region; the other, here termed PKCalpha, recognized the regulatory region of the molecule. Western blots showed that both anti-PKC antibodies stained an identical single band at approximately 80 kD. The retinal neurons showing PKC-IR were rod bipolar cells and a variety of amacrine neurons. After 3 weeks on an LD cycle, PKCalphabeta-IR in both rod bipolar and certain amacrine cells manifested a clear rhythm with a peak at zeitgeber time (ZT) of 06-10 hours and a minimum at ZT 18. No rhythm in total PKC-IR was observed when using the PKCalpha antibody, but, at ZT 06-10 hours, rod bipolar axon terminals showed increased immunostaining. After 48 hours in DD, with either antibody, rod bipolar cells showed increased PKC-IR. The PKCalpha antibody alone revealed that, after 48 hours, AII amacrine neurons, which lacked PKC-IR in an LD cycle, manifested marked PKC-IR, which became stronger after 72 hours. Light administered early in the dark period greatly increased PKCalphabeta-IR in rod bipolar and some amacrine neurons. Our data indicate that light and darkness exert a strong regulatory influence on PKC synthesis, activation, and transport in retinal neurons.
Gabriel
R
R
Department of General Zoology and Neurobiology, University of Pecs, H-7604 Pecs, Hungary.
Lesauter
J
J
Silver
R
R
Garcia-España
A
A
Witkovsky
P
P
D025042:Amacrine Cells / Q000166:cytology / Q000201:enzymology; D000818:Animals; D000918:Antibody Specificity / Q000276:immunology; D015153:Blotting, Western; D002940:Circadian Rhythm / Q000502:physiology*; D003623:Dark Adaptation / Q000502:physiology; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000378:metabolism; D055537:Light Signal Transduction / Q000502:physiology*; D008297:Male; D009474:Neurons / Q000166:cytology / Q000201:enzymology*; D010775:Photic Stimulation; D020033:Protein Isoforms / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism*; D064546:Protein Kinase C beta; D051571:Protein Kinase C-alpha; D017434:Protein Structure, Tertiary / Q000502:physiology; D051381:Rats; D020318:Rats, Long-Evans; D012160:Retina / Q000166:cytology / Q000201:enzymology*
D007527:Isoenzymes; D020033:Protein Isoforms; D011493:Protein Kinase C; D064546:Protein Kinase C beta; D051571:Protein Kinase C-alpha