Perinatal hypoxia-/ischemia-induced endothelin-1 mRNA in astrocyte-like and endothelial cells.

Under pathological conditions in the adult CNS, such as ischemia, subarachnoid hemorrhage and Alzheimer's disease, endothelin (ET)-1- and -3-like immunoreactivities are elevated in astrocytes of the injured adult brain. However, it is not clear whether this is due to increased synthesis or increased binding of ET-1. Further, it is not known whether ET-1 expression is altered in the perinatal brain after cerebral hypoxia/ischemia (H/I). Here, we determined the sites of ET-1 expression in perinatal mouse brain after H/I injury by in situ hybridization using a probe specific for the ET-1 gene. Astrocyte-like cells, which do not normally express ET-1 mRNA, showed high levels of ET-1 mRNA expression. Endothelial cells of the capillaries and small vessels also showed an increased level of ET-1 mRNA. Our data suggest that ET-1 mRNA levels in the astrocyte-like cells and vascular endothelial cells are dynamically regulated by ischemia and may participate in perinatal ischemia-related neural damage.