title: Potentiation of adenosine A1 receptor agonist CPA-induced antinociception by paeoniflorin in mice.
abstract: The effect of paeoniflorin (PF), a major constituent isolated from Paeony radix, on N6-Cyclopentyladenosine (CPA), a selective adenosine A1 receptor (A1 receptor) agonist, induced antinociception was examined in mice. In the tail-pressure test, CPA (0.05, 0.1, 0.2 mg/kg, s.c.) could induce antinociception in a dose-dependent manner. PF (5, 10, 20 mg/kg, s.c.) alone failed to exhibit any antinociceptive effect in mice; however, pretreatment of PF (20 mg/kg, s.c.) could significantly enhance CPA-induced antinociception. Additionally, pretreatment of 8-Cyclopentyl-1,3-dipropylxanthine (DPCPX, 0.25 mg/kg, s.c.), a selective A1 receptor antagonist, could antagonize the antinociceptive effect of combining CPA with PF. Furthermore, in the competitive binding experiments, PF did not displace the binding of [3H]-8-Cyclopentyl-1,3-dipropylxanthine ([3H]-DPCPX) but displaced that of [3H]-2-Chloro-N6-cyclopentyladenosine ([3H]-CCPA, a selective A1 receptor agonist) to the membrane preparation of rat cerebral cortex. These results suggested that PF might selectively increase the binding and antinociceptive effect of CPA by binding with A1 receptor.
authors.affiliation: Department of Pharmacology, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, China.
authors.forename: Da-Zhi
authors.initials: DZ
authors.lastname: Liu
authors.forename: Fei-Li
authors.initials: FL
authors.lastname: Zhao
authors.forename: Jing
authors.initials: J
authors.lastname: Liu
authors.forename: Xin-Quan
authors.initials: XQ
authors.lastname: Ji
authors.forename: Yang
authors.initials: Y
authors.lastname: Ye
authors.forename: Xing-Zu
authors.initials: XZ
authors.lastname: Zhu
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D058907:Adenosine A1 Receptor Agonists; D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D001565:Benzoates / Q000494:pharmacology*; D001952:Bridged-Ring Compounds / Q000494:pharmacology*; D005960:Glucosides / Q000494:pharmacology*; D008297:Male; D051379:Mice; D039821:Monoterpenes; D011869:Radioligand Assay; D006027:Glycosides
chemical_list: D000241:Adenosine; D058907:Adenosine A1 Receptor Agonists; D000700:Analgesics; D001565:Benzoates; D001952:Bridged-Ring Compounds; D005960:Glucosides; D039821:Monoterpenes; C015423:peoniflorin; D006027:Glycosides; C048599:N(6)-cyclopentyladenosine