Loss of nAChRa7 increases BBB permeability after TBI, an effect mimicked by exogenous administration of proinflammatory cytokines. A, Compared with injured wild-type mice, injured Chrna7^−/− mice had significantly increased extravasation of Evans Blue dye assessed 24 h after injury, indicating enhanced BBB permeability after TBI (n = 5/group). B, Administration of the combination of IL-1β and TNF-α (8 μg/kg each) to brain-injured wild-type mice (n = 6/group) significantly increased BBB permeability 24 h after injury, as indicated by increased Evans Blue dye extravasation into the injured brain. *p < 0.05 by Student's t test. Data are presented as the mean ± SEM.