title: Effect of hypericin on confocal imaging of Ca2+ signaling in cultured human retinal pigment epithelium.
abstract: OBJECTIVE
  To investigate the mechanism of the Ca2+ signaling in cultured human retinal pigment epithelial (RPE) cells with the protein kinase C(PKC) specific inhibitor-hypericin stimulation.
  
  
  METHODS
  Cultured human RPE cells were analyzed using the fluorescence Ca2+ dye fluo-3 AM and laser scanning confocal microscope(LSCM) after stimulation with 100 nM phorbol 12-myristate 13-acetate(PMA) and (or) 5 concentrations of hypericin(1, 2, 3, 4 and 5 microM).
  
  
  RESULTS
  The normal fluorescence in RPE cells was strong and distributed throughout the cells. The nucleus appeared to be more fluorescent than the cytoplasm. After stimulation with PMA alone or 5 concentrations of hypericin, a rapid decrease in flurescence intensity was observed. There was no obvious difference in decreased curve among 5 concentrations. However, after stimulation with a 24 hr preincubation of PMA and 5 concentrations of hypericin, a further decrease was not observed.
  
  
  CONCLUSIONS
  Fluo-3 AM appears to be a good indicator of the change in Ca2+ occurring in RPE cells and hypericin is a strong inhibitor of Ca2+ influx channel. Hypericin has potential as a therapeutic drug for proliferative vitreoretinopathy(PVR), the inhibitory effect on PVR might be caused by blocking the PKC activity and inhibiting Ca2+ influx pathway.
authors.affiliation: Department of Ophthalmology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Q
authors.initials: Q
authors.lastname: Gao
authors.forename: Y
authors.initials: Y
authors.lastname: Hui
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
authors.forename: L
authors.initials: L
authors.lastname: Wang
mesh_terms: D000328:Adult; D000814:Aniline Compounds / Q000378:metabolism; D000873:Anthracenes; D015220:Calcium Channels / Q000502:physiology; D020013:Calcium Signaling / Q000187:drug effects* / Q000502:physiology; D002450:Cell Communication; D005456:Fluorescent Dyes / Q000378:metabolism; D017629:Gap Junctions; D006801:Humans; D018613:Microscopy, Confocal / Q000379:methods; D010569:Perylene / Q000031:analogs & derivatives* / Q000494:pharmacology*; D010857:Pigment Epithelium of Eye / Q000166:cytology* / Q000378:metabolism / Q000648:ultrastructure; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D012160:Retina / Q000166:cytology* / Q000378:metabolism; D014966:Xanthenes / Q000378:metabolism
chemical_list: D000814:Aniline Compounds; D000873:Anthracenes; D015220:Calcium Channels; D005456:Fluorescent Dyes; D014966:Xanthenes; C059715:Fluo-3; D010569:Perylene; C004965:hypericin; D011493:Protein Kinase C