Involvement of nitric oxide in long-term potentiation of spinal nociceptive responses in rats.
Nitric oxide plays an important role in spinal nociception. The present study explored the effects of nitric oxide on the spinal long-term potentiation associated with nociception. (1) Nitric oxide synthase inhibitor L-NAME (1 mM, 20 microl) and the nitric oxide scavenger hemoglobin (2 mg/ml, 20 mul) strikingly blocked the induction of tetanic sciatic stimulation-induced spinal long-term potentiation of C-fiber-evoked field potentials. L-arginine, a substrate of nitric oxide synthase, completely reversed L-NAME-induced inhibition. However, D-NAME (1 mM, 20 microl), an inactive form of L-NAME, had little effect on the spinal LTP. (2) The same tetanic sciatic stimulation induced long-term thermal hyperalgesia, which was blocked by pre-application of L-NAME. These results suggest the involvement of nitric oxide in the spinal long-term potentiation of C-fiber-evoked field potentials and related behavior changes.
Zhang
Xi-Chun
XC
Institute of Neurobiology, Fudan University, 220 Handan Road, Shanghai 200433, People's Republic of China.
Zhang
Yu-Qiu
YQ
Zhao
Zhi-Qi
ZQ
D000704:Analysis of Variance; D000818:Animals; D001120:Arginine / Q000494:pharmacology; D004347:Drug Interactions; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005071:Evoked Potentials / Q000502:physiology / Q000528:radiation effects; D007839:Functional Laterality; D006454:Hemoglobins / Q000494:pharmacology; D006930:Hyperalgesia / Q000503:physiopathology; D017774:Long-Term Potentiation / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D036421:Nerve Fibers, Unmyelinated / Q000502:physiology / Q000528:radiation effects; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D009619:Nociceptors / Q000502:physiology*; D010147:Pain Measurement / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000502:physiology / Q000528:radiation effects; D012584:Sciatic Nerve / Q000502:physiology / Q000528:radiation effects; D013116:Spinal Cord / Q000187:drug effects / Q000201:enzymology* / Q000503:physiopathology*; D013997:Time Factors
D004791:Enzyme Inhibitors; D006454:Hemoglobins; D001120:Arginine; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester