Characterization of the binding of [3H]-L-NG-nitro-arginine in rat brain.

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