Two secreted retinal factors regulate different stages of development of the outer blood-retinal barrier

Brain Res Dev Brain Res. 2000 Feb 7;119(2):259-67. doi: 10.1016/s0165-3806(99)00183-2.


The retinal pigment epithelium (RPE) lies at the interface between the neural retina and the choriocapillaries where it forms a blood-retinal barrier. Like endothelial regions of the blood-brain barrier, the development of the RPE barrier is a gradual, multistep process. A culture model of chick RPE was used to study this development. The permeability of the tight junctions that limit diffusion between neighboring RPE cells was measured as the transepithelial electrical resistance (TER). Embryonic day 14 (E14) retinas were used to make a conditioned medium that lowered the permeability of cultured RPE. The TER of cultures prepared from E14 RPE was twice that of E7 RPE. In each culture, retinal conditioned medium increases the TER 2-2.5 fold. The active factors of conditioned medium that affected each culture had different physical properties. The factor that affected E7 was protease-resistant with a Mr<10 kDa, but the factor that affected E14 appeared to be a protein of approximately 49 kDa. Unlike the effect of astrocyte conditioned medium on endothelia, retinal conditioned medium did not act synergistically with cAMP. These data indicate that the chick retina, which lacks astrocytes, uses different diffusible factors to regulate different stages of tight junction development.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adrenergic Agonists / pharmacology
  • Animals
  • Biological Transport / drug effects
  • Blood-Brain Barrier / drug effects
  • Blood-Brain Barrier / physiology*
  • Catecholamines / pharmacology
  • Cell Fractionation
  • Cells, Cultured
  • Chick Embryo
  • Chromatography, Gel
  • Culture Media, Conditioned / chemistry
  • Culture Media, Conditioned / pharmacology
  • Dopamine Agonists / pharmacology
  • Electric Impedance
  • Endopeptidases / pharmacology
  • Eye Proteins / analysis
  • Eye Proteins / metabolism
  • Indoles
  • Pigment Epithelium of Eye* / growth & development
  • Pigment Epithelium of Eye* / metabolism
  • Serotonin Receptor Agonists / pharmacology
  • Tight Junctions / metabolism


  • Adrenergic Agonists
  • Catecholamines
  • Culture Media, Conditioned
  • Dopamine Agonists
  • Eye Proteins
  • Indoles
  • Serotonin Receptor Agonists
  • indolamine
  • Endopeptidases