Introduction: In order to study the alterations of beta 1 and 2 integrins mRNA level in rat lumbar spinal cord following the induction of chronic pain and its effect on the development of tolerance to morphine analgesia, we examined the level of expression of these genes in the presence of chronic pain, which is an inhibitor of morphine tolerance. We used induction of chronic pain alone and ...

Previous studies have shown that the extract of Papaver rhoeas reduces morphine dependence, locomotor activity and reward. In present study, the effects of hydro-alcohol extract of Papaver Rhoeas on the tolerance to analgesic effects of morphine in mice have been investigated using tail flick method. Subcutaneous (s.c.) administration of morphine (1, 2, 5 and 10 mg/kg) induced analgesia. Howeve...

Previous studies have shown that the extract of Papaver rhoeas reduces morphine dependence, locomotor activity and reward. In present study, the effects of hydro-alcohol extract of Papaver Rhoeas on the tolerance to analgesic effects of morphine in mice have been investigated using tail flick method. Subcutaneous (s.c.) administration of morphine (1, 2, 5 and 10 mg/kg) induced analgesia. Howeve...

introduction: ultra low dose (uld) morphine induces hyperalgesia which is mediated by excitatory gscoupled opioid receptors. this study was designed to investigate the development of tolerance to hyperalgesic effect of morphine. also we attempt to seek possible similarity, in view of gs proteins, between hyperalgesic effect of uld and hyperalgesic effect after tolerance to hd. method: male wist...

introduction: transient receptor potential vanilloid type 1 (trpv1) and protein kinase cγ (pkcγ) are involved in sensitization/desensitization to noxious stimuli. we aimed to examine the gene expression levels of trpv1 and pkcγ in rat lumbosacral cord and midbrain on days 1, 4 and 8 of induction of morphine analgesic tolerance. methods: two groups of male wistar rats received twice daily saline...

Mice were rendered tolerant and dependent to morphine by subcutaneous injection of morphine over a period of 5 days. The effects of acute and chronic administration of dihydropyridine calcium channel antagonist nifedipine on the development of tolerance and naloxone-precipitated morphine withdrawal signs were investigated. A single injection of nifedipine proved to be effective in inhibiti...

Chronic use of morphine is accompanied by the development of morphine tolerance, which is one of the major problems associated with opiate treatment. Experimental evidence indicates that melanocortin 4 receptor (MC4R) is involved in development of morphine tolerance. Therefore, we investigated the influence of repeated intrathecal injection of a MC4R antagonist (HS014) on the development of mor...

Morphine analgesic tolerance is heritable in both humans and rodents, with some individuals and strains exhibiting little and others exhibiting robust tolerance. 129S6/SvEv and 129P3/J mice reportedly do not demonstrate tolerance to morphine analgesia. Using our laboratory's standard morphine tolerance regimen and a between-subjects design, tolerance developed in the hot plate and tail withdraw...

UNLABELLED Morphine is among the most prevalent analgesics prescribed for chronic pain. However, prolonged morphine treatment results in the development of analgesic tolerance. An abundance of evidence has accumulated indicating that central nervous system glial cell activity facilitates pain transmission and opposes morphine analgesia. While the midbrain ventrolateral periaqueductal gray (vlPA...