Detection of the multidrug resistance of P-glycoprotein in healthy tissues: the example of the blood-brain barrier.
The blood-brain barrier is formed by the cerebral capillary endothelial cells, joined together by tight junctions. These cells express the general endothelial cell markers as well as specific markers found on endothelial cells forming physiological barriers such as gamma-glutamyltranspeptidase, the glucose transporter Glut1 and the neutral amino-acid transporter. Using the monoclonal antibodies C219 and MRK16, we have revealed by Western blot and immuno-histochemistry the expression of the multidrug resistance P-glycoprotein on isolated rat cerebral cortex capillaries. On the other hand, P-glycoprotein was not detectable in brain cortex homogenates. P-glycoprotein thus appears to be a blood-brain barrier endothelium-specific marker which could regulate brain penetration of xenobiotics and thus participate in the neuroprotection of the brain.
Lechardeur
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Centre de recherche de Vitry-Alfortville, UMR 133 CNRS/Rhône Poulenc Rorer, Vitry-sur-Seine, France.
Phung-Ba
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Wils
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Scherman
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D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000187:drug effects*; D000818:Animals; D001812:Blood-Brain Barrier / Q000187:drug effects*; D015153:Blotting, Western; D002540:Cerebral Cortex / Q000737:chemistry; D018432:Drug Resistance, Multiple; D006801:Humans; D007150:Immunohistochemistry; D051381:Rats; D017207:Rats, Sprague-Dawley
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1