title: Nitric oxide modulates articular sensory discharge and responsiveness to bradykinin in normal and arthritic rats in vivo.
abstract: Nitric oxide is implicated in peripheral nociceptive processing. This study determined the effects of the nitric oxide synthase inhibitor, L-NAME, on neural discharge from articular C-fibre afferents innervating normal and arthritic ankle joints in anaesthetized rats. Intra-arterial injection of L-NAME (10-20 mg kg(-1)) increased neural discharge in normal and arthritic ankle joints, whereas D-NAME (30 mg kg(-1)) had no effect. The excitation induced by L-NAME (20 mg kg(-1)) was reduced by co-injecting the nitric oxide precursor, L-arginine (50 mg kg(-1)). L-NAME (20 mg kg(-1)) also enhanced responsiveness to bradykinin (10 microg) but only in arthritic rats, whereas L-arginine (50 mg kg(-1)) reduced the excitation by bradykinin (30 microg) in both groups. These results provide evidence that nitric oxide modulates articular C-fibre activity and reduces responsiveness to bradykinin.
authors.affiliation: Department of Neuroscience, University of Edinburgh Medical School, UK.
authors.forename: D C
authors.initials: DC
authors.lastname: Kelly
authors.forename: A U
authors.initials: AU
authors.lastname: Asghar
authors.forename: C G
authors.initials: CG
authors.lastname: Marr
authors.forename: D S
authors.initials: DS
authors.lastname: McQueen
mesh_terms: D000344:Afferent Pathways / Q000187:drug effects / Q000502:physiology; D000818:Animals; D000843:Ankle Joint / Q000187:drug effects* / Q000502:physiology; D001120:Arginine / Q000494:pharmacology; D001169:Arthritis, Experimental; D001920:Bradykinin / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D017746:Joint Capsule / Q000187:drug effects* / Q000502:physiology; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology*; D009412:Nerve Fibers / Q000187:drug effects* / Q000502:physiology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D051381:Rats; D017208:Rats, Wistar
chemical_list: D004791:Enzyme Inhibitors; D001120:Arginine; D019001:Nitric Oxide Synthase; D001920:Bradykinin; D019331:NG-Nitroarginine Methyl Ester