CHARACTERIZATION OF THE BINDING OF [H-3] L-N(G)-NITRO-ARGININE IN RAT-BRAIN

In the present study tritiated L-N(G)-nitro-arginine (L-NOARG) has bee n shown to label specific binding sites in rat brain cytosol. We concl ude that this ligand is directly labelling nitric oxide synthase (NOS) . This conclusion is based on our observations (i) that binding was st ereoselectively inhibited by L-arginine, in preference to D-arginine, and (ii) that a number of different NOS inhibitors were able to displa ce [H-3]-L-NOARG binding at similar concentrations to those required t o inhibit the activity of rat brain cytosol NOS in functional studies.