Immunocytochemical localization of phosphatidylinositol-4,5-bisphosphate in dark- and light-adapted rat retinas.
Light-mediated hydrolysis of phosphatidylinositol-4,5-bisphosphate (TPI) to 1,2-diacylglycerol and D-myo-inositol 1,4,5-triphosphate (IP3) has been reported in the visual photoreceptor cells. We have investigated the localization of the TPI antigenic sites in dark- and light-adapted rat retinas using rabbit anti TPI antibodies (Ab). Sprague-Dawley rats were dark-, or light-adapted, or were exposed to a light flash. The eyes were fixed immediately and the tissue sections stained with the rabbit anti TPI Ab. The peroxidase-antiperoxidase method was used to find the localization of the TPI antigenic site. Image analysis of the sections was performed to obtain optical density profiles of the stain. Dark-adapted retinas showed intense staining of the rod outer segment (OS) layer but much less staining of the rod inner segment layer. Compared with the OS of dark-adapted retinas, those of the flash-bleached retinas were stained much less. The OS of fully bleached retinas showed little or no staining. The anti TPI Ab-protein A-gold conjugate intensely stained disks from dark-adapted retina but those from bleached retina much less. Our results suggest that rapid hydrolysis of TPI in rat rod outer segments occurs in vivo in response to light.
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ND
Das
T
T
Yoshioka
D
D
Samuelson
H
H
Shichi
D000818:Animals; D000906:Antibodies / Q000276:immunology; D000918:Antibody Specificity; D003623:Dark Adaptation; D000939:Epitopes; D006651:Histocytochemistry; D007124:Immunoenzyme Techniques; D008027:Light; D019269:Phosphatidylinositol 4,5-Diphosphate; D010716:Phosphatidylinositols / Q000032:analysis*; D010786:Photoreceptor Cells / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012160:Retina / Q000166:cytology / Q000276:immunology / Q000378:metabolism*
D000906:Antibodies; D000939:Epitopes; D019269:Phosphatidylinositol 4,5-Diphosphate; D010716:Phosphatidylinositols