Document Type

Journal Article

Department/Unit

School of Chinese Medicine

Title

Analgesic effect of paeoniflorin in rats with neonatal maternal separation-induced visceral hyperalgesia is mediated through adenosine A1 receptor by inhibiting the extracellular signal-regulated protein kinase (ERK) pathway

Language

English

Abstract

Paeoniflorin (PF), a chief active ingredient in the root of Paeonia lactiflora Pall (family Ranunculaceae), is effective in relieving colorectal distention (CRD)-induced visceral pain in rats with visceral hyperalgesia induced by neonatal maternal separation (NMS). This study aimed at exploring the underlying mechanisms of PF's analgesic effect on CRD-evoked nociceptive signaling in the central nervous system (CNS) and investigating whether the adenosine A1 receptor is involved in PF's anti-nociception. Results: CRD-induced visceral pain as well as phosphorylated-extracellular signal-regulated protein kinase (p-ERK) and phospho-cAMP response element-binding protein (p-CREB) expression in the CNS structures of NMS rats were suppressed by NMDA receptor antagonist dizocilpine (MK-801) and ERK phosphorylation inhibitor U0126. PF could similarly inhibit CRD-evoked p-ERK and c-Fos expression in laminae I-II of the lumbosacral dorsal horn and anterior cingulate cortex (ACC). PF could also reverse the CRD-evoked increased glutamate concentration by CRD as shown by dynamic microdialysis monitoring in ACC, whereas, DPCPX, an antagonist of adenosine A1 receptor, significantly blocked the analgesic effect of PF and PF's inhibition on CRD-induced p-ERK and p-CREB expression. These results suggest that PF's analgesic effect is possibly mediated by adenosine A1 receptor by inhibiting CRD-evoked glutamate release and the NMDA receptor dependent ERK signaling. © 2009 Elsevier Inc. All rights reserved.

Keywords

Adenosine A1 receptor, Analgesia, Extracellular signal-regulated protein kinase (ERK), Neonatal maternal separation, Paeoniflorin

Publication Date

2009

Source Publication Title

Pharmacology Biochemistry and Behavior

Volume

94

Issue

1

Start Page

88

End Page

97

Publisher

Elsevier

DOI

10.1016/j.pbb.2009.07.013

Link to Publisher's Edition

http://dx.doi.org/10.1016/j.pbb.2009.07.013

ISSN (print)

00913057

ISSN (electronic)

18735177

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