Human cerebrovascular receptor expression. (A) Double staining with actin shows expression of angiotensin II type 1 (AT1) receptors in the medial layer. (B) AT1 receptor expression in fresh and in cultured vessel segments in the presence of vehicle, SB-590885, or SB-386023. The increase in AT1 receptor immunoreactivity after culture was diminished significantly after treatment with SB-590885, and diminished slightly after treatment with SB-386023. (C) No difference in endothelin type A (ETA) receptor expression was observed. Autofluorescence was observed in internal elastic lamina. Data were obtained with epifluorescence microscopy. MED - medial layer, ADV - adventitial layer, and IEL - internal elastic lamina.