Peripheral modulation of rat knee joint afferent mechanosensitivity by nociceptin/orphanin FQ.
The peripheral effects of nociceptin were examined in normal and acutely inflamed rat knee joints by analyzing single unit recordings from articular primary afferents in response to normal and extreme rotation of the knee. Bolus close intraarterial injection of nociceptin (0.01, 1 and 100 microM) caused a sensitization of normal and inflamed knee joint afferents in response to movements in the normal working range of the joint. When the joint was hyper-rotated, nociceptin had no significant effect on afferent discharge rate in normal knees, however, in inflamed joints the top dose of the neuropeptide caused a decrease in articular mechanosensitivity. These findings suggest that nociceptin seems to be involved in the control of peripheral nociceptive mechanisms, although the behaviour of the peptide is dependent upon the inflammatory status of the tissue.
McDougall
J J
JJ
McCaig Centre for Joint Injury and Arthritis Research, University of Calgary, 3330 Hospital Drive NW,., T2N 4N1, Calgary AB, Canada. mcdougaj@ucalgary.ca
Pawlak
M
M
Hanesch
U
U
Schmidt
R F
RF
D000818:Animals; D018846:Excitatory Amino Acids / Q000819:agonists*; D007719:Knee Joint / Q000187:drug effects / Q000294:innervation* / Q000502:physiology; D008297:Male; D008465:Mechanoreceptors / Q000187:drug effects*; D009475:Neurons, Afferent / Q000187:drug effects* / Q000502:physiology*; D018847:Opioid Peptides / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D011957:Receptors, Opioid / Q000819:agonists*; D009435:Synaptic Transmission / Q000187:drug effects; D000097629:Nociceptin
D018846:Excitatory Amino Acids; D018847:Opioid Peptides; D011957:Receptors, Opioid; D000097629:Nociceptin