Nitric oxide synthase and soluble guanylate cyclase are involved in spinal cord wind-up activity of monoarthritic, but not of normal rats.
While increasing evidence points to a role for the nitric oxide (NO)/cyclic guanosine 3,5-monophosphate (GMPc) cascade in hyperalgesia and allodynia, participation of the NO/GMPc pathway in synaptic processing in the spinal cord, i.e. wind-up activity, is less clear. We studied the effects of intrathecal administration of Nomega-nitro-L-arginine methyl ester (L-NAME) and methylene blue, inhibitors of NO synthase and guanylate cyclase respectively, on wind-up activity developed in a C-fiber reflex response paradigm. 5, 10 and 20 microg i.t. of L-NAME or methylene blue did not modify spinal wind-up in normal rats, while a dose-dependent inhibition of wind-up was observed in monoarthritic rats. Results suggest that the NO/GMPc pathway plays a non-significant role in wind-up activity evoked in normal animals, while it may be essential in chronic pain processing.
Laurido
Claudio
C
Laboratory of Neurobiology, Department of Biology, Faculty of Chemistry and Biology, University of Santiago of Chile, P.O. Box 40 Correo 33, Santiago, Chile.
Hernández
Alejandro
A
Constandil
Luis
L
Pelissier
Teresa
T
D000818:Animals; D001169:Arthritis, Experimental / Q000201:enzymology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006162:Guanylate Cyclase; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000502:physiology*; D010146:Pain / Q000201:enzymology*; D010147:Pain Measurement / Q000187:drug effects / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley; D018160:Receptors, Cytoplasmic and Nuclear / Q000037:antagonists & inhibitors / Q000502:physiology*; D000071756:Soluble Guanylyl Cyclase; D013116:Spinal Cord / Q000187:drug effects / Q000201:enzymology*
D004791:Enzyme Inhibitors; D018160:Receptors, Cytoplasmic and Nuclear; D019001:Nitric Oxide Synthase; D006162:Guanylate Cyclase; D000071756:Soluble Guanylyl Cyclase