title: Complete inhibition of purinoceptor agonist-induced nociception by spinorphin, but not by morphine.
abstract: We found that spinorphin, a novel neuropeptide showed analgesia in a different manner compared with morphine. By measuring flexor responses induced by the intraplanter injection of substances, the presence of three different types of sensory neurons were demonstrated. Although spinorphin completely blocked 2-metylthioadenosine (2-MeS ATP, a P2X(3) agonist)-induced responses, morphine did not. On the other hand, morphine-induced blockade of bradykinin (BK, a B(2)-receptor agonist)-responses was attenuated by pertussis toxin (PTX) treatment, whereas that of spinorphin was not. Thus it is suggested that spinorphin has a spectrum of analgesia which covers the blockade of nociception insensitive to morphine.
authors.affiliation: Department of Molecular Pharmacology and Neuroscience, Nagasaki University School of Pharmaceutical Sciences, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Ueda
authors.forename: S
authors.initials: S
authors.lastname: Matsunaga
authors.forename: M
authors.initials: M
authors.lastname: Inoue
authors.forename: Y
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: T
authors.initials: T
authors.lastname: Hazato
mesh_terms: D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D000241:Adenosine / Q000031:analogs & derivatives* / Q000378:metabolism; D000701:Analgesics, Opioid / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn; D001920:Bradykinin / Q000378:metabolism; D002211:Capsaicin / Q000494:pharmacology; D016291:Dizocilpine Maleate / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D008297:Male; D051379:Mice; D009020:Morphine / Q000494:pharmacology*; D009475:Neurons, Afferent / Q000187:drug effects; D018696:Neuroprotective Agents / Q000494:pharmacology; D009842:Oligopeptides / Q000494:pharmacology*; D010146:Pain / Q000188:drug therapy*; D037342:Pertussis Toxin; D010880:Piperidines / Q000494:pharmacology; D011480:Protease Inhibitors / Q000494:pharmacology*; D058913:Purinergic Agonists; D013872:Thionucleosides / Q000378:metabolism; D013997:Time Factors; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
chemical_list: D000701:Analgesics, Opioid; D018691:Excitatory Amino Acid Antagonists; D018696:Neuroprotective Agents; D009842:Oligopeptides; D010880:Piperidines; D011480:Protease Inhibitors; D058913:Purinergic Agonists; D013872:Thionucleosides; D010566:Virulence Factors, Bordetella; C080755:3-(2-methoxybenzylamino)-2-phenylpiperidine; C082392:spinorphin; C021714:2-methylthioadenosine; D016291:Dizocilpine Maleate; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D009020:Morphine; D037342:Pertussis Toxin; D000241:Adenosine; D002211:Capsaicin; D001920:Bradykinin