Fig. 3.

Characterization of density gradients for the fractionation of cerebral microvessels. Rat cerebral microvessels prepared from brains from either saline- or λ-carrageenan-injected animals were homogenized in a neutral pH, detergent-free buffer (containing MgCl₂ and CaCl₂) and fractionated in a discontinuous 0–20% OptiPrep gradient (in the absence of MgCl₂ and CaCl₂). One-millilitre fractions were collected from the top of the gradient. (a) Mean densities and standard errors from three separate gradients (per animal treatment) on different days (n = 15 rats). (b) Distribution of protein across a representative gradient. (c) Western blots of the first 15 fractions from a representative gradient (for each animal treatment) probed for plasma membrane lipid raft markers (Rab13 and caveolin-1), the Golgi membrane protein, β-COP, and the nuclear membrane protein, nucleoporin. Bars at the bottom of the figure indicate the distribution of lipid raft and non-raft markers on the gradient. Data shown are representative of at least two independent experiments (n = 10–15 rats) for each treatment condition. Sal, saline; Carr, carrageenan.