Nitric oxide modulates articular sensory discharge and responsiveness to bradykinin in normal and arthritic rats in vivo.
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.
Kelly
D C
DC
Department of Neuroscience, University of Edinburgh Medical School, UK.
Asghar
A U
AU
Marr
C G
CG
McQueen
D S
DS
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
D004791:Enzyme Inhibitors; D001120:Arginine; D019001:Nitric Oxide Synthase; D001920:Bradykinin; D019331:NG-Nitroarginine Methyl Ester