Potentiation of adenosine A1 receptor agonist CPA-induced antinociception by paeoniflorin in mice.
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.
Liu
Da-Zhi
DZ
Department of Pharmacology, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, China.
Zhao
Fei-Li
FL
Liu
Jing
J
Ji
Xin-Quan
XQ
Ye
Yang
Y
Zhu
Xing-Zu
XZ
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
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