Tight junction proteins paracellular permeability

Baida MS, Whitney JA, Flores C, Gonzalez-Mariscal L, Cereijido M, and Matter K [1996] Functional dissociation of paracellular permeability and transepithelial electrical resistance and disruption of the apical-basolateral intramembrane diffusion barrier by the expression of a mutant tight junction membrane protein. J Cell Biol 134 1031-1049... 

The blood-brain barrier forms the interface between the bloodstream and the brain parenchyma and thus controls the passage of endogenous substances and xenobiotics into and out of the central nervous system. Brain microvessels exhibit a variety of unique structural features, such as an extremely tight endothelium without fenestration, a very low rate of pinocytosis, tight junctions between endothelial cells excluding paracellular permeability, and a series of polarized transport proteins. The following chapter describes the structural and functional characteristics of the blood-brain barrier with emphasis on transport proteins, as well as in vitro techniques, which allow studying this complex barrier in the brain. 

Fluorescein retention measurements are converted to relative amount of fluorescence normalized against protein concentration. Test chemical exposure causing disruption of tight junctions will allow fluorescein molecules to penetrate the comeal tissue and become trapped within its epithelial layer. Thus, fluorescein molecules are used as a permeability tracer and applied in defining comeal epithelial and endothelial permeability (Watsky et al. 1989). FITC-retention provides a quantitative assessment for paracellular leakage... 

Baida, M. S., Whitney, J. A., Flores, C., Gonzalez, S., Cereijido, M., and Matter, K. (1996). Functional dissociation of paracellular permeability and transepithelial electrical resistance and disruption of the apical-basolateral intramembrane diffusion barrier by expression of a mutant tight junction membrane protein. J. Cell Biol. 134, 1031-1049. Cereijido, M., Valdes, J., Shoshani, L., and Contreras, R. G. (1998). Role of tight junctions in establishing and maintaining cell polarity. Anna. Rev. Physiol. 60, 161-177. 

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