THE ANTINOCICEPTIVE EFFECT OF 1-(2-TRIFLUOROMETHYLPHENYL) IMIDAZOLE (TRIM), A POTENT INHIBITOR OF NEURONAL NITRIC-OXIDE SYNTHASE IN-VITRO, IN THE MOUSE

1-(2-trifluoromethylphenyl)imidazole (TRIM) is a potent inhibitor of n euronal (mouse cerebellar) and inducible (lung from endotoxin-pretreat ed rats) isoforms of nitric oxide synthase (NOS) with IC50 values of 2 8.2 mu M and 27.0 mu M, respectively. In contrast, TRIM is a poor inhi bitor of bovine aortic endothelial NOS with an IC50 of 1057.5 mu M TRI M (10-50 mg kg(-1)) administered i.p. exhibits dose-related antinocice ptive activity in the mouse (assessed as inhibition of late phase form alin-induced hindpaw licking behaviour) with an ED(50) of 85.8 mu mol kg(-1). In contrast, TRIM (50 mg kg(-1), i.p.) failed to influence mea n arterial blood pressure in the urethane-anaesthetized mouse. Thus, T RIM may be of use as an experimental tool with which to investigate th e biological roles of nitric oxide (NO) within the central nervous sys tem.