Antagonistic effects of methanolic extract of Polygala telephioides on morphine responses in mice

Nobuaki Egashira, Jian Chen Li, Ai Mizuki, Keita Yamauchi, Tomoko Matsuda, Megumi Osajima, Michihiko Matsushita, Kenichi Mishima, Katsunori Iwasaki, Shuji Hara, Nobufumi Ono, Ryoji Nishimura, Toshihiro Nohara, Michihiro Fujiwara

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7 Citations (Scopus)


The present study was undertaken to investigate the antagonistic effects of the methanolic extract of Polygala telephioides (PT) on morphine responses in mice. Single administration of PT tended to antagonize the morphine-induced analgesia in a hot-plate test. Moreover, PT (300 mg/kg, p.o.) improved the morphine-induced memory impairment in an elevated plus maze test. However, PT alone had no effect on behaviors in the open-field, hot-plate and elevated plus maze tests. We investigated the effects of PT on naloxone-induced jumping (as withdrawal sign) in morphine-dependent mice. To induce dependence, mice were twice daily treated with morphine (10-45 mg/kg, s.c.) for 5 days. Co-administrations of PT (10, 100 and 300 mg/kg, p.o.) during repeated morphine treatments significantly suppressed the naloxone (10 mg/kg, i.p.)-induced jumping. However, the naloxone-induced jumping was not affected by a single large administration of PT on the 5th day. The inhibitory effect of PT on the naloxone-induced jumping was due to the development of dependence rather than expression of withdrawal sign. Moreover, single administration of PT (300 mg/kg, p.o.) decreased the morphine levels in plasma. These results indicate that PT may be useful in facilitating narcotic detoxification.

Original languageEnglish
Pages (from-to)193-198
Number of pages6
JournalJournal of Ethnopharmacology
Issue number1-2
Publication statusPublished - Mar 8 2006
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Pharmacology
  • Drug Discovery


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