The effect of dexamethasone on spinal glutamine synthetase and glutamate dehydrogenase expression in morphine-tolerant rats

Gong-Jhe Wu, Zhi Hong Wen, Wu Fu Chen, Yi Chen Chang, Chen Hwan Cherng, Chih Shung Wong

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

BACKGROUND: Excitatory amino acids play an important role in morphine tolerance. Recently, we demonstrated that a single morphine challenge induces an increase in spinal cerebrospinal fluid excitatory amino acid concentrations in morphine-tolerant rats, and that dexamethasone inhibits the development of morphine tolerance. We further examined the effect of intrathecal dexamethasone infusion on the development of morphine tolerance and on expression of the intracellular glutamate metabolizing enzymes, glutamate dehydrogenase and glutamine synthetase, in the spinal cord. METHODS: Male Wistar rats, implanted with an intrathecal catheter, were divided into four groups that were infused for 5 days with intrathecal morphine (15 μg/h), saline (1 μL/h), dexamethasone (2 μg/h), or dexamethasone (2 μg/h) plus morphine (15 μg/h). On Day 5, the spinal cords were removed and prepared for Western blot analysis of glutamate dehydrogenase and glutamate synthetase. RESULTS: Glutamate dehydrogenase and glutamate synthetase concentrations were downregulated in the morphine-tolerant rat spinal cords. Concurrent infusion of dexamethasone attenuated morphine tolerance and the associated glutamate dehydrogenase and glutamate synthetase downregulation. CONCLUSION: Intrathecal dexamethasone attenuates long-term morphine infusion-induced glutamate dehydrogenase and glutamate synthetase downregulation and antinociceptive tolerance.

Original languageEnglish
Pages (from-to)726-730
Number of pages5
JournalAnesthesia and Analgesia
Volume104
Issue number3
DOIs
Publication statusPublished - Mar 2007
Externally publishedYes

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Glutamate Dehydrogenase
Glutamate-Ammonia Ligase
Morphine
Dexamethasone
Glutamic Acid
Ligases
Spinal Cord
Excitatory Amino Acids
Down-Regulation
Cerebrospinal Fluid
Wistar Rats
Catheters
Western Blotting

ASJC Scopus subject areas

  • Anesthesiology and Pain Medicine

Cite this

The effect of dexamethasone on spinal glutamine synthetase and glutamate dehydrogenase expression in morphine-tolerant rats. / Wu, Gong-Jhe; Wen, Zhi Hong; Chen, Wu Fu; Chang, Yi Chen; Cherng, Chen Hwan; Wong, Chih Shung.

In: Anesthesia and Analgesia, Vol. 104, No. 3, 03.2007, p. 726-730.

Research output: Contribution to journalArticle

Wu, Gong-Jhe ; Wen, Zhi Hong ; Chen, Wu Fu ; Chang, Yi Chen ; Cherng, Chen Hwan ; Wong, Chih Shung. / The effect of dexamethasone on spinal glutamine synthetase and glutamate dehydrogenase expression in morphine-tolerant rats. In: Anesthesia and Analgesia. 2007 ; Vol. 104, No. 3. pp. 726-730.
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