A natural peptide with NMDA inhibitory activity reduces tonic pain in the formalin model.
The aim of this study was to assess whether a natural peptide, histogranin, isolated from chromaffin cells and possessing NMDA receptor inhibitory activity, could reduce tonic pain. Rats received intrathecal injections of the stable analog [Ser1]histogranin (SHG), prior to induction of the formalin response. SHG markedly suppressed the second tonic phase of the formalin response compared with saline vehicle. A U-shaped dose-response curve was obtained. SHG had no effect on phase 1 acute pain responses. These findings indicate that SHG acts in a similar fashion as other, non-peptide, NMDA antagonists in suppressing tonic, but not acute pain. The presence of the natural peptide in chromaffin cells may contribute to the analgesic effects of adrenal medullary implants.
Siegan
J B
JB
Department of Anatomy and Cell Biology, University of Illinois at Chicago 60612, USA.
Sagen
J
J
D000818:Animals; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D007278:Injections, Spinal; D008297:Male; D010146:Pain / Q000188:drug therapy*; D010147:Pain Measurement; D011506:Proteins / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors*
D018691:Excitatory Amino Acid Antagonists; D011506:Proteins; D016194:Receptors, N-Methyl-D-Aspartate; C082312:histogranin