Intrathecal interferon-gamma facilitates the spinal nociceptive flexor reflex in the rat.
The effect of intrathecal (i.t.) injection of the cytokine interferon-gamma) (IFN-gamma) on the spinal nociceptive flexor reflex was examined in decerebrate, spinalized, unanesthetized rats. IFN-gamma elicited an initial intense, brief facilitation of the flexor reflex followed by a sustained reflex facilitation lasting 40 +/- 5 min (range 20-65 min). The initial and prolonged reflex facilitations by IFN-gamma were partially and totally blocked, respectively, by i.t. pretreatment with nitro-L-arginine-ester, an inhibitor of nitric oxide synthase, at doses which did not influence spinal cord blood flow. Spinal application of IFN-gamma produced powerful and prolonged facilitation of the flexor reflex, possibly reflecting a hyperalgesic action of this cytokine. The facilitatory effect of IFN-gamma was mediated, at least in part, by the activation of the L-arginine-nitric oxide pathway. Thus, IFN-gamma released in the CNS may participate in eliciting pain and hyperalgesia in infectious or neuroinflammatory diseases where there is increased production of this cytokine.
Xu
X J
XJ
Department of Laboratory Medical Science and Technology, Karolinska Institute, Huddinge, Sweden.
Hao
J X
JX
Olsson
T
T
Kristensson
K
K
van der Meide
P H
PH
Wiesenfeld-Hallin
Z
Z
D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D016207:Cytokines / Q000494:pharmacology; D005260:Female; D007278:Injections, Spinal; D007371:Interferon-gamma / Q000494:pharmacology*; D019331:NG-Nitroarginine Methyl Ester; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012018:Reflex / Q000187:drug effects*; D013116:Spinal Cord / Q000187:drug effects*
D016207:Cytokines; D009569:Nitric Oxide; D007371:Interferon-gamma; D001120:Arginine; D019331:NG-Nitroarginine Methyl Ester