It is interesting that the gene for endothelin 1 was up-regulated in the dorsolateral (dl) prefrontal cortex (PFC) of PTSD cases because endothelin 1 causes vasoconstriction, which would be deleterious but it has also been reported to correlate positively, which would be beneficial, with numbers of oligodendrocyte precursor cells (OPC) in humans with strokes and leukoencephalopathy [12]. The gene discussed is EDN1; the disease is post-traumatic stress disorder.