title: Synergistic analgesic effects between neuronostatin and morphine at the supraspinal level.
abstract: Neuronostatin, a 13-amino acid peptide, is encoded in the somatostatin pro-hormone. I.c.v. administration of neuronostatin produces a significant antinociceptive effect in the mouse tail-flick test, which is mediated by endogenous opioid receptor. However, the direct functional interaction between morphine and neuronostatin has not been characterized. In the present study, effect of neuronostatin on morphine analgesia was investigated in the tail-flick test. Our findings showed that i.c.v. administration of neuronostatin (0.3nmol/mouse i.c.v.) significantly enhanced the antinociceptive effect of morphine (2.5, 5 or 10μg/kg) at the supraspinal level. Results of antagonism experiments suggested that the synergistic analgesia induced by morphine and neuronostatin was mediated by μ- and к-opioid receptors not δ-opioid receptor. In conclusion, there may be a cascade amplification phenomenon when morphine and neuronostatin were co-administered in acute pain model. The above results provide evidence for the potential use of neuronostatin in combination with morphine to control pain and addiction.
authors.affiliation: Institute of Biochemistry and Molecular Biology, School of Life Sciences, Lanzhou University, 222 Tian Shui South Road, Lanzhou 730000, PR China.
authors.forename: Shao-Bin
authors.initials: SB
authors.lastname: Yang
authors.forename: Ai-Min
authors.initials: AM
authors.lastname: Yang
authors.forename: Ting-Ji
authors.initials: TJ
authors.lastname: Shao
authors.forename: Shu-Fang
authors.initials: SF
authors.lastname: Su
authors.forename: Qiang
authors.initials: Q
authors.lastname: Chen
mesh_terms: D000698:Analgesia; D000701:Analgesics, Opioid / Q000494:pharmacology*; D000818:Animals; D004357:Drug Synergism; D007276:Injections, Intraventricular; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D009270:Naloxone / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D059225:Nociception / Q000187:drug effects; D010446:Peptide Fragments / Q000494:pharmacology* / Q000502:physiology; D011957:Receptors, Opioid / Q000378:metabolism; D013004:Somatostatin / Q000494:pharmacology* / Q000502:physiology
chemical_list: D000701:Analgesics, Opioid; D009292:Narcotic Antagonists; D010446:Peptide Fragments; D011957:Receptors, Opioid; C554543:neuronostatin protein, rat; D009270:Naloxone; D013004:Somatostatin; D009020:Morphine