title: Protein kinase C and IP3 in photoresponses of functionally intact rod outer segments: constraints about their role.
abstract: Protein kinase C and polyphosphoinositide metabolism are reported to affect light-activated processes in cell free systems. To investigate their role in phototransduction under more physiological conditions the effects of nonhydrolyzable inositol trisphosphate (IP3) analogs as well as of protein kinase C and phospholipase C inhibitors on the characteristics of the electrical light response were studied. Rod outer segments were dialyzed in whole-cell voltage clamp and photoresponses in the presence and absence of the tested compounds were compared. None of the compounds influenced the light responses suggesting that neither IP3 nor protein kinase C participate in the phototransduction cascade. A number of different proposals about the participation of protein kinase C and inositol trisphosphate (IP3) in the phototransduction process based on a wide variety of in vitro experiments should therefore be reevaluated.
authors.affiliation: Department of Physiology and Biophysics, University of Washington, Seattle 98195, USA.
authors.forename: H
authors.initials: H
authors.lastname: Jindrová
authors.forename: P B
authors.initials: PB
authors.lastname: Detwiler
mesh_terms: D000818:Animals; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D015544:Inositol 1,4,5-Trisphosphate / Q000031:analogs & derivatives / Q000502:physiology*; D008027:Light; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000502:physiology*; D012374:Rod Cell Outer Segment / Q000502:physiology* / Q000528:radiation effects; D015398:Signal Transduction; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors
chemical_list: D004791:Enzyme Inhibitors; D015544:Inositol 1,4,5-Trisphosphate; D011493:Protein Kinase C; D010738:Type C Phospholipases