Localization of the Na+-D-glucose cotransporter SGLT1 in the blood-brain barrier

Immunoreactivity of the Na+-D-glucose cotransporter SGLT1 was demonstrated in intracerebral capillaries of rat and pig. Immunostaining suggested that SGLT1 is located in the luminal membrane of the endothelial cells and in intracellular vesicles. Using in situ hybridization, SGLT1 mRNA was not detectable in intracerebral capillaries of non-treated or sham-operated Wistar rats. However, 1 day after a transient occlusion of the right middle cerebral artery, SGLT1 mRNA was detected in capillaries of both brain hemispheres. Expression of SGLT1 was also demonstrated in primary cultures of capillary endothelial cells from pig using polymerase chain reaction after reverse transcription and western blotting. The data suggest that SGLT1 participates in transport of D-glucose across the blood-brain barrier and is upregulated after brain ischemia and reperfusion.