Blockade of the development of opioid tolerance and dependence by methylene blue

Mengwei Zang, Aimin Meng, Qi Shen, Yue Sun, Qing Wang, Jingsheng Liu

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

AIM: To explore the mechanism of blockade of opiate tolerance and dependence by methylene blue (MB), a soluble guanylyl cyclase (sGC) inhibitor. METHODS: An inducible nitric oxide synthase (iNOS) gene-expressing nerve cell line was used as an in vitro model system. Competitive protein binding assay and radioimmunoassay were used to examine the intracellular cAMP and cGMP content. iNOS catalytic activity was assayed by measuring the calcium-independent conversion of 3H-arginine to 3H-citrulline. Intracellular free Ca2+ concentration was monitored with confocal laser scanning microscopy. Cells were exposed to δ-opioid agonists DPDPE (D-Pen2, D-Pen5-enkephalin) or morphine alone, and MB (10-6 mol·L-1) combined with various opioid agonist for 48 hours. Cell withdrawal response was then precipitated by the addition of naloxone for 15 minutes. RESULTS: MB was found to significantly inhibit the elevation of cGMP level which resulted from long-term treatment with opioid agonists and not affect the changes of forskolin-stimulated cAMP accumulation, NOS activity and [Ca2+]i. CONCLUSION: Methylene blue attenuates the development of opioid tolerance and withdrawal effects mainly through inhibition of sGC activity and subsequent down-regulation of NO-cGMP pathway.

Original languageEnglish (US)
Pages (from-to)576-581
Number of pages6
JournalYaoxue Xuebao
Volume34
Issue number8
StatePublished - Aug 1 1999
Externally publishedYes

Keywords

  • Cyclic AMP
  • Cyclic GMP
  • Intercellular free calcium
  • Methylene blue
  • Nitric-oxide synthase
  • Opiate dependence

ASJC Scopus subject areas

  • Molecular Medicine
  • Pharmacology, Toxicology and Pharmaceutics(all)

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