Norepinephrine Suppresses Inducible Nitric Oxide Synthase Activity in Rat Astroglial Cultures

: Exposure of primary rat astrocyte cultures to bacterial endotoxin lipopolysaccharide (LPS) causes expression of a Ca 2+ ‐in‐dependent form of nitric oxide synthase (NOS). In these cells, the presence of norepinephrine (NE) caused a dose‐dependent inhibition of the LPS induction of NOS activity, with an IC 50 value of 100 nMand significant suppression at 100 pAf. Short incubations (5‐40 min) with NE were as effective as 24‐h continuous...