Molecular Mechanisms of the Inner Blood-Retinal Barrier Transporters

  • Masatoshi Tomi
  • Ken-ichi Hosoya
Part of the Ophthalmology Research book series (OPHRES)


The inner blood–retinal barrier (inner BRB) forms complex tight junctions of retinal capillary endothelial cells to prevent the free diffusion of substances between the circulating blood and the neural retina. Thus, understanding of the inner BRB transport mechanisms could provide a basis for strategies of drug delivery to the retina. Recent development of several analytical methods has succeeded in showing that the inner BRB is equipped with several membrane transporters such as GLUT1, monocarboxylate transporter 1 (MCT1), creatine transporter (CRT), xCT, L-type amino acid transporter 1 (LAT1), taurine transporter (TauT), equilibrative nucleoside transporter 2 (ENT2), organic anion transporter polypeptide 1a4 (Oatp1a4), multidrug resistance 1a (mdr1a), and ATP-binding cassette transporter G2 (Abcg2). These transporters play essential roles in supplying nutrients to the retina and are responsible for the efflux of neurotransmitter metabolites, toxins, and xenobiotics.


Diabetic Retinopathy Organic Anion Neural Retina Goto Kakizaki Organic Anion Transporter Polypeptide 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



This work was supported, in part, by a grant-in-aid for scientific research from the Japan Society for the Promotion of Science and a grant for research on sensory and communicative disorders by the Ministry of Health, Labor, and Welfare, Japan. The authors thank Drs. T. Terasaki, S. Ohtsuki, K. Katayama, T. Kondo, and M. Tachikawa and Messrs. T. Funaki, T. Isobe, H. Abukawa, A. Minamizono, M. Mori, Y. Ohshima, T. Terayama, and K. Nagase for valuable suggestions and technical assistance.


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Copyright information

© Humana Press, a part of Springer Science + Business Media, LLC 2008

Authors and Affiliations

  • Masatoshi Tomi
    • 1
  • Ken-ichi Hosoya
    • 1
  1. 1.Department of PharmaceuticsGraduate School of Medical and Pharmaceutical Sciences, University of ToyamaJapan

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