title: Antinociceptive mechanisms of platycodin D administered intracerebroventricularly in the mouse.
abstract: Platycodin D administered intracerebroventricularly (i.c.v.) showed an antinociceptive effect in a dose-dependent manner as measured by the tail-flick assay. The antinociception induced by platycodin D was maintained at least 1 h. MK-801 [(+/-)-5-methyl-10,11-dihydro-5 H-dibenzo[ a,d]cyclohepten-5,10-imine maleate], a competitive N-methyl- D-aspartic acid (NMDA) receptor antagonist, or CNQX (6-cyano-7-nitroquinoxaline-2,3-dione), a non-NMDA receptor antagonist, muscimol (a GABA(A) receptor agonist), or baclofen (a GABA(B) receptor antagonist), or sulfated cholecystokinin (CCK-8 s; CCK A receptor agonist), injected i.c.v. significantly reduced the inhibition of the tail-flick response induced by platycodin D administered i.c.v. Additionally, intrathecal (i.t.) pretreatment with yohimbine (an alpha 2 -adrenergic receptor antagonist) or methysergide (a serotonin receptor antagonist) dose-dependently attenuated inhibition of the tail-flick response induced by i.c.v. administered platycodin D. However, naloxone (an opioid receptor antagonist) did not affect the inhibition of the tail-flick response induced by platycodin D. Our results suggest that platycodin D has an antinociceptive effect when it is administered supraspinally, and supraspinal GABA(A), GABA(B), NMDA and non-NMDA receptors are involved in platycodin D-induced antinociception. Furthermore, platycodin D administered supraspinally produces antinociception by stimulating descending noradrenergic and serotonergic, but not opioidergic, pathways.
mesh_terms: D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D058669:Adrenergic alpha-2 Receptor Antagonists; D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D001418:Baclofen / Q000494:pharmacology; D002240:Carbohydrate Sequence; D016291:Dizocilpine Maleate / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D018755:GABA Agonists / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D007276:Injections, Intraventricular; D007278:Injections, Spinal; D008297:Male; D008784:Methysergide / Q000494:pharmacology; D051379:Mice; D008813:Mice, Inbred ICR; D008969:Molecular Sequence Data; D009118:Muscimol / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D010147:Pain Measurement / Q000187:drug effects; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D031238:Platycodon; D011949:Receptors, Cholecystokinin / Q000037:antagonists & inhibitors / Q000187:drug effects; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors; D012503:Saponins / Q000737:chemistry / Q000494:pharmacology*; D012702:Serotonin Antagonists / Q000494:pharmacology; D012844:Sincalide / Q000031:analogs & derivatives* / Q000494:pharmacology; D013623:Tail / Q000187:drug effects; D014315:Triterpenes / Q000737:chemistry / Q000494:pharmacology*; D015016:Yohimbine / Q000494:pharmacology
chemical_list: C090019:8-sulfocholecystokinin octapeptide; D058669:Adrenergic alpha-2 Receptor Antagonists; D000316:Adrenergic alpha-Agonists; D000700:Analgesics; D018691:Excitatory Amino Acid Antagonists; D018755:GABA Agonists; D018756:GABA Antagonists; D009292:Narcotic Antagonists; D010936:Plant Extracts; D011949:Receptors, Cholecystokinin; D016194:Receptors, N-Methyl-D-Aspartate; D012503:Saponins; D012702:Serotonin Antagonists; D014315:Triterpenes; D009118:Muscimol; D015016:Yohimbine; D009270:Naloxone; D016291:Dizocilpine Maleate; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; C108953:platycodin D; D001418:Baclofen; D012844:Sincalide; D008784:Methysergide