NITRIC-OXIDE SYNTHASE IN CEREBROVASCULAR ENDOTHELIAL-CELLS IS INHIBITED BY BREFELDIN-A

Nitric oxide synthase (NOS) is present within cerebrovascular endothelial cells in a distinct membrane-bound juxtanuclear location. The enzyme product, nitric oxide, causes vasodilation as well as stimulation of ADP-ribosylations of some proteins. The activity of specific stimulatory ADP-ribosylation factors, associated with the Golgi complex (GC), has been shown to be blocked by brefeldin A (BFA). We present evidence that BFA disperses the GC, disrupts NOS/NADPH diaphorase staining and inhibits NOS activity in addition to its previously described activities.