FPR1 and Stroke: Although the infiltrated fMLP in this condition might not be as high as it is in the blood, or even under detectable levels, it could still be a potential threat to DA neurons because fMLP is toxic to DA neurons at concentration as low as 10−13 M. In addition, in a number of acute cerebral pathologies, including stroke, trauma, and meningitis, the blood–brain barrier permeability increases, allowing plasma proteins to enter the brain parenchyma.