• Toxicological Research
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• v.11 no.1
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• pp.63-68
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• 1995

N-methyl-D-aspartate(NMDA) receptor has been well known as an important mediator of several forms of neural and behavioral plasticity. But different results were reported about the effect of MK-801 or dextromethorphan on opioid dependence. The present studies examined whether NMDA receptor antagonists can alter the opioid dependence and tolerance in rodents. Naloxone precipitated withdrawal symptoms and changes of locomotor activities were observed in MK-801 or dextromethorphan pretreated morphine-dependent rats. Tail-flick assay was used for morphine analgesia and tolerance was found after 4 day's consecutive injections (10 mg/kg, s.c., twice/day) of morphine in mice. Locomotor activity was increased and the withdrawal symptoms were decreased by the pretreatment of MK-801 in morphine-dependent rats. But 0.3 mg/kg i.p. of MK-801 intensified the body weight loss and produced severe ataxia and rotation although some withdrawal signs were attenuated. Morphine induced analgesic tolerance was inhibited by the pretreatment of MK-801 and dextromethorphan. Dextromethorphan was more potent than MK-801 in inhibiting the development of the analgesic tolerance in mice. These results suggest that NMDA system may be involved in opioid withdrawal and analgesic tolerance but appropriate caution should be requested when MK-801 is used in combination with opioid because of untoward neurologic signs.

• The Korean Journal of Pain
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• v.19 no.1
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• pp.8-16
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• 2006

The regulators of the G protein signaling (RGS) proteins are responsible for the rapid acceleration of the GTPase-activity intrinsic to the heterotrimeric G protein alpha subunits. As GTPase-activating proteins (GAP), the RGS proteins negatively regulate the G-protein signals. Recently, the RGS proteins are known to be one of the important regulators of opioid signal transduction and the development of tolerance. The aim of this study was to review the recent discovery and understanding of the role of RGS proteins in opioid signaling and the development of tolerance. This information will be useful for medical personnel, particularly those involved in anesthesia and pain medicine, by helping them improve the effective use of opioids and develop new drugs that can prevent opioid tolerance.

• The Korean Journal of Pain
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• v.24 no.1
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• pp.7-12
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• 2011

Background: Adenosine has been shown to have a wide spectrum of unique pain-relieving effects in various clinical situations. The aim of this study was to investigate the effects of intraoperative adenosine infusion on acute opioid tolerance and opioid induced hyperalgesia induced by remifentanil in adult patients undergoing tonsillectomy. Methods: For this study, ninety patients were randomly allocated into groups that receive either adenosine (adenosine group) or saline (remifentnail group) intravenously under remifentanil based anesthesia and saline (sevoflurane group) under sevoflurane anesthesia. The patients in adenosine group received adenosine at dose of $80\;{\mu}g$/kg/min, and those in remifentnail group and sevoflurane group received an equal volume of saline 10 minutes after the induction of anesthesia until the end of surgery. Intraoperative evaluation included time weighted mean remifentanil dose, and postoperative evaluations included degree of pain severity at 1, 6, 12, and 24 hours, time to first postoperative requirement, and analgesic dose required during 24 hours after operation. Results: Time weighted mean remifentanil dose during intraoperative period in adenosine group was significantly lower than that of remifentnail group (P = 0.00). The first postoperative analgesic were required earlier in remifentanil group than sevoflurane group or adenosine group (P = 0.00). Pethidine requirement during 24 hours in sevoflurane group and adenosine group was significantly lower than that of remifentnail group (P = 0.00). The visual analog scale scores for pain in sevoflurane group and adenosine group were significantly lower than those of remifentnail group for 12 hours after operation (P = 0.00). Incidence of hypotension (P = 0.024) and number of ephedrine administered (P = 0.011) in adenosine group were significantly higher than those of sevoflurane group. Conclusions: The above results suggest that intraoperative adenosine infusion prevent acute opioid tolerance and opioid induced hyperalgesia induced by remifentanil.

• Journal of Ginseng Research
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• v.13 no.2
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• pp.239-241
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• 1989

Naloxone partially antagonized the analgesic effect of a large dose of morphine and inhibited the development of an acute type tolerance. Ginseng total saponins did not antagonize the analgesia of a large dose of morphine but inhibited the delrelopment of acute and delayed types tolerance. The morphine analgesia and the development of acute type tolerance were affected by the opioid receptor antagonist, naloxone, but the development of acute type tolerance was not. Ginseng total saponins partially inhibited the development of the delayed type tolerance that was not inhibited by naloxone, but also partially suppressed the development of the acute type tolerance that was completely inhibited by naloxone. These results imply that the partial inhibition of the development of the acute and delayed types tolerance by ginseng total saponins is not mediated by the opioid receptors.

• Journal of Ginseng Research
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• v.23 no.4
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• pp.239-246
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• 1999

The analgesic effect of ginsenosides or morphine was determined following intrathecal (i.t.) administration in rat tail-flick test. The effects of intrathecal co-administration of ginsenosides with morphine on the development of opioid tolerance and dependence were also examined using rat tail-flick test and naloxone-pre-cipitated withdrawal, respectively. Administration of ginsenosides (i.t.) produced a weak antinociception in a dose-dependent manner. Administration of morphine (i.t.) also produced antinociception in a dose-dependent manner. The $ED_50$ was $1.20\;{\mu}g\;(1.14\~1.29\;{\mu}g)$. However, the acute co-administration of $200{\mu}g$ ginsenosides with 0.1-1.0${\mu}g$ morphine did not show additive effect on morphine induced analgesia in rat tail-flick test. I.t. co-administration of 200 ${\mu}g$ ginsenosides with 10 ${\mu}g$ morphine for 7 days inhibited development of tolerance induced by 10 ${\mu}g$ morphine in rat tail-flick test, although i.t. co-administration of 50 or 100 ${\mu}g$ ginsenosides with morphine was without effect. I.t. co-administration of 200 ${\mu}g$ ginsenosides for 7 days also partially attenuated the development of morphine dependence as assessed by naloxone-precipitated withdrawal. In conclusion, these results suggest that i.t. administered ginsenosides produce a weak antinociception in rat tail-flick test and also prevent opioid tolerance and attenuate opioid dependence in chronic treatment with morphine at the spinal sites.

• The Korean Journal of Pain
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• v.22 no.1
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• pp.58-64
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• 2009

Background: Magnesium is a noncompetitive antagonist of the N-methyl-D aspartate (NMDA) receptor. Magnesium is thought to be involved in opioid tolerance by way of inhibiting calcium entry into cells. Methods: The patients were randomly assigned to three groups according to the anesthetic regimens: Group M received magnesium sulfate and Group C received saline intravenously under remifentanil-based anesthesia. Group S received saline intravenously under sevoflurane based anesthesia in place of remifentanil. The patients in the group M received 25% magnesium sulfate 50 mg/kg in 100 ml of saline, and those patients in groups C and S received an equal volume of saline before induction of anesthesia; this was followed by 10 mg/kg/h infusion of either magnesium sulfate (group M) or an equal volume of saline (groups C and S) until the end of surgery. Pain was assessed on a visual analog scale at 1, 6, 12, 24, and 36 hours after the operation. The time to the first postoperative analgesic requirement and the cumulative analgesic consumption were evaluated in the three groups. Results: The visual analog scales for pain and the cumulative analgesic consumption were significantly greater in group C than in other groups. The time to first postoperative analgesic requirement was significantly shorter in group C than that in the other groups. There were no differences between group M and S for side effects. Conclusions: A relatively high dose and continuous remifentanil infusion is associated with clinically relevant evidence of acute opioid tolerance. NMDA-receptor antagonist, magnesium sulfate as an adjuvant analgesic prevents opioid tolerance in patients who are undergoing major abdominal surgery under high dose and continuous remifentanil infusion-based anesthesia.

• The Korean Journal of Pain
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• v.37 no.3
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• pp.211-217
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• 2024

Background: Tolerance to the analgesic effects of opioids and non-steroidal anti-inflammatory drugs (NSAIDs) is a major concern for relieving pain. Thus, it is highly valuable to find new pharmacological strategies for prolonged therapeutic procedures. Biguanide-type drugs such as metformin (MET) are effective for neuroprotection and can be beneficial for addressing opioid tolerance in the treatment of chronic pain. It has been proposed that analgesic tolerance to NSAIDs is mediated by the endogenous opioid system. According to the cross-tolerance between NSAIDs, especially sodium salicylate (SS), and opiates, especially morphine, the objective of this study was to investigate whether MET administration can reduce tolerance to the anti-nociceptive effects of SS. Methods: Fifty-six male Wistar rats were used in this research (weight 200-250 g). For induction of tolerance, SS (300 mg/kg) was injected intraperitoneally for 7 days. During the examination period, animals received MET at doses of 50, 75, or 100 mg/kg for 7 days to evaluate the development of tolerance to the analgesic effect of SS. The hot plate test was used to evaluate the drugs' anti-nociceptive properties. Results: Salicylate injection significantly increased hot plate latency as compared to the control group, but the total analgesic effect of co-treatment with SS + Met50 was stronger than the SS group. Furthermore, the effect of this combination undergoes less analgesic tolerance over time. Conclusions: It can be concluded that MET can reduce the analgesic tolerance that is induced by repeated intraperitoneal injections of SS in Wister rats.

• Journal of Ginseng Research
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• v.32 no.1
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• pp.1-7
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• 2008

Ginseng saponin has been shown to inhibit the development of dependence on morphine, cocaine, methamphetamine, but the antinarcotics effects of ginseng on nalbuphine remains still largely unknown. Ginseng administration attenuated the naloxone-induced jumping behavior on nalbuphine dependent mice. The development of morphine dependence was mediated through ${\mu}-opioid$ receptor, however, development of nalbuphine dependence was mediated through ${\kappa}-opioid$ receptor. However, it was found that the efficacy of analgesic antagonism of GTS was mediated through the serotonergic mechanism, not mediated through the opioid receptor. In addition, ginseng administration modulated cellular signal transduction in the brain. The increased NMDA receptor subunit (NR1, pNR1), phosphate extracellular signal regulated protein kinase (pERK), phosphate cAMP response element binding protein (pCREB) expression by nalbuphine was decreased by the administration of ginseng powder in cortex, hippocampus, striatum of rat brain. These results suggest that ginseng could be one of the targets of antinarcotic therapies to reduce the development of tolerance and dependence on nalbuphine as well as morphine.

• Proceedings of the Ginseng society Conference
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• 1990.06a
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• pp.36-44
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• 1990

The analgesic effect of morphine was antagonized and the development of tolerance was suppressed by the modification of the neurologic function in the animals treated with ginseng saponins. The activation of the spinal descending inhibitory systems as well as the supraspinal structures by the administration of morphine was inhibited in the animals treated with ginseng saponins intracerebrally or intrathecally The development of morphine tolerance and dependence, and the abrupt expression of naloxone induced abstinence syndrome were also inhibited by ginsenoside Kbl , Rba, Rgl and Re. These results suggest that ginsenoside Kbl, Rba, Rgl and Re are the bioactive components of panax ginseng on the inhibition of the development of morphine tolerance and dependence, and the inhibition of abrupt abstinence syndrome. In addition, further research on the minor components of Panax ginseng should be investigated. A single or daily treatment with ginseng saponins did not induce any appreciable changes in the brain level of monoamines at the various time intervals and at the various day intervals, respectively The inhibitory or facilitated effects of ginseng saponins on electrically evoked contractions in guinea pig ileum (U-receptor) and mouse was definers (5·receptor) were not mediated through opioid receptors. The antagonism of a x receptor agonist, U-, iO.488H was also not mediated through opioid receptors in the animals treated with ginseng saponins, bolt mediated through serotonergic mechanisms. Ginseng saponins inhibited morphine S-dehydrogenase that catalyzed the production of morphine from morphine, and increased hepatic glutathione contents for the detoxification of morphine. This result suggests that the dual action of the above plays an important role in the inhibition of the development of morphine tolerance and dependence.

• The Korean Journal of Physiology and Pharmacology
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• v.4 no.4
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• pp.291-299
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• 2000

Morphine or butorphanol was continuously infused into cerebroventricle (i.c.v.) with the rate of $26\;nmol/{\mu}l/h$ for 3 days, and the withdrawal from opioid was rendered 7 hrs after the stopping of infusion. The expression of physical dependence produced by these opioids was evaluated by measuring the naloxone-precipitated withdrawal signs. The withdrawal signs produced in animals dependent on butorphanol (kappa opioid receptor agonist) were similar to those of morphine (mu opioid receptor agonist). Besides the behavioral modifications, opioid withdrawal affected G protein expression in the central nervous system. The G-protein ${\alpha}-subunit$ has been implicated in opioid tolerance and withdrawal. The effects of continuous infusion of morphine or butorphanol on the modulation of G protein ${\alpha}-subunit$ mRNA were investigated by using in situ hybridization study. In situ hybridization showed that the levels of $G\;{\alpha}s$ and $G\;{\alpha}i$ were changed during opioid withdrawal. Specifically, the level of $G\;{\alpha}s$ mRNA was decreased in the cortex and cerebellar granule layer during the morphine and butorphanol withdrawal. The level of $G\;{\alpha}i$ mRNA was decreased in the dentate gyrus and cerebellar granule layer during the morphine withdrawal. However, the level of $G\;{\alpha}i$ mRNA was significantly elevated during the butorphanol withdrawal. These results suggest that region-specific changes of G protein ${\alpha}-subunit$ mRNA were involved in the withdrawal from morphine and butorphanol.