Tissue concentrations of glutamate transporters.

The number of molecules of GLAST or GLT-1 per volume of hippocampal tissue and per cell membrane area were calculated from the dot blot experiment using the following assumptions: the mouse hippocampus contains 97.8 g of protein per Kg of tissue [68], has a density of 1.05 g/cm3 [69], and that the molecular weigh of GLAST and GLT-1 are 59,619 and 62,027 Da, respectively (mean±SD; n = 3). The astrocyte plasma membrane density was set to 3.15 μm2/μm3 for mice (according to measures obtained from our 3D axial STEM tomography data) and rats (see Results section for details).