• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.50-62
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• 1994

Opium, morphine and rotated natural and synthetic opiates have been used since antiquity, and to the present, for the relief of moderate and severe pain. Morphine and pharmacologically related drugs, however, produced an array of undesired or dangerous side effect that limit their use as analgesics. Prominent among the limiting side effects are constipation, respiratory depression, release of prolactin, and liability for the production of drug dependence. It was our aim to develop, if possible, a drug or class of drugs with analgesic activity similar to that of morphine, but without the serious side effects associated with morphine. Our overall strategy was to take advantage of advancing knowledge concerning multiple types of opioid receptors, to develop ligands selective for the delta type receptors, to determine whether delta receptor agonists offer advantages over mu agonists, then to design compounds with pharmacokinetic properties compatible with practical therapeutic application. All but the last of these objectives have been realized.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.6
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• pp.687-693
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• 1998

This study was performed to examine the mean arterial pressure and nociceptive jaw opening reflex after microinjection of glutamate into the amygdala in freely moving rats, and to investigate the mechanisms of antinociceptive action of amygdala. Animals were anesthetized with pentobarbital sodium (40 mg/kg, ip). A stainless steel guide cannula (26 gauge) was implanted in the amygdala and lateral ventricle. Stimulating and recording electrodes were implanted into each of the incisor pulp and anterior digastric muscle. Electrodes were led subcutaneously to the miniature cranial connector sealed on the top of the skull with acrylic resin. After 48 hours of recovery from surgery, mean arterial pressure and digastric electromyogram (dEMG) were monitored in freely moving rats. Electrical shocks (200 ${\mu}sec$ duration, $0.5{\sim}2$ mA intensity) were delivered at 0.5 Hz to the dental pulp every 2 minutes. After injection of 0.35 M glutamate into the amygdala, mean arterial pressure was increased by $8{\pm}2$ mmHg and dEMG was suppressed to $71{\pm}5%$ of the control. Injection of 0.7 M glutamate elevated mean arterial pressure by $25{\pm}5$ mmHg and suppressed dEMG to $20{\pm}7%$ of the control. The suppression of dEMG were maintained for 30 minutes. Naloxone, an opioid receptor antagonist, inhibited the suppression of dEMG elicited by amygdaloid injection of glutamate from $28{\pm}4\;to\;68{\pm}5%$ of the control. Methysergide, a serotonin receptor antagonist, also inhibited the suppression of dEMG from $33{\pm}5\;to\;79{\pm}4%$ of the control. However, phentolamine, an ${\alpha}-adrenergic$ receptor antagonist, did not affect the suppression of dEMG. These results suggest that the amygdala can modulate both cardiovascular and nociceptive responses and that the antinociception of amygdala seems to be attributed to an augmentation of descending inhibitory influences on nociceptive pathways via serotonergic and opioid pathways.

• Journal of Ginseng Research
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• v.14 no.2
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• pp.178-186
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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 saponine intracerebrally or intrathecally. The development of morphine tolerance and dependence, and the abrupt expression of naloxone inducted abstinence syndrom were also inhibited by ginsenoside Rb1, Rb2, Rg1 and Re. These results suggest that ginsenoside Rbl, Hbs, 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 sindrome. In addition, further research on the minor components of Pnnnxkinsenl should be investigated. A single or daily treatment with ginseng saponins did not induce any appreciable changes in the brain in level of monoamines at the variolls 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 ($\mu$-receptor) and mouse vats deferens ($\delta$-receptor) were not mediated through opioid receptors. The antagonism of a $\chi$ receptor agonist, U-50, 488H was also not mediated through opioid receptors in the animals treated with ginseng saponins, but mediated through serotonergic mechanisms. Ginseng saponins inhibited morphine 6-dehydrogenase which catalyzed the production of morphinone from morphine, and increased hepatic glutathione contents for the detoxication of morphinone. 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 Pain
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• v.14 no.2
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• pp.150-155
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• 2001

Background: Tramadol is known to be a weak opioid. However, it has also been shown that tramadol is an effective norepinephrine and serotonin uptake blocker, which may be effective in the treatment of neuropathic pain. The present study was undertaken in order to assess the antinociceptive action of tramadol and to investigate possible antinociceptive mechanisms by using antagonists in an animal neuropathic pain models in rats. Methods: Rats were prepared with tight ligation at the left 5 and 6th lumbar spinal nerves (Kim and Chung's neuropathic pain model). The antinociceptive effects of tramadol (10, 20, and 50 mg/kg i.p.) in rats with neuropathic pain were assessed. Additionally, following coadministration of antagonists such as naloxone (1 mg/kg i.p.), yohimbine (1 mg/kg i.p.) and ritanserin (1 mg/kg i.p.) with 50 mg/kg of tramadol, the responses to mechanical and thermal stimuli were measured over a two-hour period. Results: Tramadol displayed potent antinociceptive effects in a dose-dependent manner on rats with neuropathic pain (P < 0.05). The effects of tramadol were inhibited by coadministered naloxone and yohimbine in rats with mechanical and thermal allodynia, respectively (P < 0.05). However, there were no significant changes in the pain behaviors in the case of ritanserin. Conclusions: Tramadol showed significant antinociceptive effects in rats with regards to neuropathic pain against both mechanical and thermal allodynia. The antinociceptive effect on the mechanical stimuli is medicated via an opioid receptor. However, it appears that the antinociceptive effects on thermal allodynia are mediated via a noradrenalin receptor vice a serotonergic receptor.

• Korean Journal of Acupuncture
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• v.35 no.1
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• pp.27-35
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• 2018

Objectives : The purpose of this study was to investigate the analgesic effect of electroacupuncture(EA) and radio-frequency warm needling(RFWN) stimulation in acupoint combination on ankle sprained pain in rats. Methods : The lateral ligaments of the Sprague-Dawley rats ankle were injured surgically resulting in sprain, of which was divided into EA, RFWN treatment groups and control group without treatment. The level of pain was measured through foot weight bearing force ratio followed by calculating pain relief. To stimulate proximal or distal area in ankle sprain, combination of proximal acupoints(GB34-GB39) and distal acupoints(GB39-GB42) from sprain area were applied, respectively, to either EA or RFWN stimulation. In addition, naltrexone or phentolamine was injected intraperitoneally before the stimulation to observe the pathway of analgesic effects. Results : In the proximal combination of GB34-GB39, EA and RFWN significantly increased pain relief compared to the control group (p<0.05). However, in distal combination with GB39-GB42, both EA and RFWN stimulation did not relieve pain due to ankle sprains. In the combination of GB34-GB39, the analgesia of EA was inhibited by blockade of the ${\alpha}$-adrenoceptor receptor. The analgesia of RFWN was inhibited by blockade of the ${\alpha}$-adrenoceptor receptor as well as ${\mu}$-opioid receptor. Conclusions : We observed that the proximal combination was effective in relieving pain when the treatment by acupoint combination was applied to the ankle sprain pain. Also, it was confirmed that this analgesia was also related to the pathways of ${\mu}$-opioid receptors and/or ${\alpha}$-adrenoceptors.

• Journal of Acupuncture Research
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• v.20 no.2
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• pp.85-97
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• 2003

Introduction : In this study, the analgesic effect and its mechanism of bee venom aqua-acupuncture on complete Freund's adjuvant-induced arthritis in rats was investigated. It has been reported from a neurochemical standpoint that bee venom exerts antinociceptive effects on inflammation and that the opioid system and adrenergic system play important roles in acupuncture analgesia. however, it is not known whether central opioid and ${\alpha}2$-adrenergic components of the intrinsic descending analgesic system are activated after bee venom aqua-acupuncture. Methods : Bee venom(1mg/kg) was subcutaneously aqua-acupunctured into Joksamni($ST_{36}$) of rats with complete Freund's adjuvant(CFA)- induced arthritis and was checked of increase in TFL. Opioid and ${\alpha}_2$-adrenergic neurotransmitter system were examined by naloxone as an opioid receptor antagonist, and yohimbine as ${\alpha}_2$-adrenoceptor antagonist prior to bee venom aqua-acupuncture. Results : The following results have been obtained. 1. The tail flick latency in the rat model with adjuvant-induced arthritis was significantly decreased in 2 weeks. 2. The tail flick latency in the rat model with adjuvant-induced arthritis was increased in bee venom aqua-acupuncture group compared to the normal saline aqua-acupuncture group. 3. Analgesic effect of bee venom was antagonized by yohimbine not by naloxone pretreatment in the rat model adjuvant-induced arthritis. Conclusions : Bee venom aqua-acupuncture has an analgesic effect on the rat model of adjuvant-induced of adjuvant-induced arthritis and has antinociception mediated by ${\alpha}_2$-adrenergic system.

• Journal of Life Science
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• v.21 no.2
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• pp.176-182
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• 2011

Deep seawater (DSW) generally refers to seawater at depths equal to or greater than 200 meters. DSW is rich in inorganic materials which have attracted attention for its various applications. In this study we investigated the effects of the DSW upwelled from the East Sea, offshore Yang Yang (KangWon-do, Korea), on the expression of ${\mu}$-opioid receptor (MOR) of cultured rat hippocampal neurons. Neurons were grown in a minimal essential medium containing 10% (v/v) fetal bovine serum and either 25% (v/v) distilled water, or hardness (H) 800, or H 1000 DSW. Cultures grown in the presence of DSW with H 800 and H 1000 exhibited robust MOR immunoreactive signals in both neurons and astrocytes. Interestingly, the increase in MOR immunoreactive signals was more dramatic in astrocytes than in neurons. Statistical analysis revealed that the relative intensities for MOR clusters increased approximately 4-fold in astrocytes cultured in H 800 and H 1000 media. These increases were statistically very significant (p<0.001). In contrast, the increase in intensities for MOR immunoreactive signals was relatively less dramatic in neurons, where only the increase in the H 1000 culture was statistically very significant (p<0.001). These results indicated that DSW promotes expression of MOR in both neurons and astrocytes, and more significantly in the latter.

• Biomolecules & Therapeutics
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• v.18 no.3
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• pp.316-320
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• 2010

Pruritus is one of major symptoms in atopic dermatis. The pathophysiological mechanism of pruritus is unclear. The search for pruritogen is important in elucidating the pathophysiological mechanism of pruritus in atopic dermatitis. Glucosylsphingosine (Gsp) is upregulated in the strateum corneum of atopic dermatitis patients. We investigated to determine whether Gsp induces itch-scratch responses (ISRs) in mice. Intradermal administration of Gsp induces ISRs. Gsp dose-dependently induced scratching response at 50-500 nmol/site range. Pretreatment with naltrexone, an opioid $\mu$ receptor antagonist, and capsaicin, a TrpV1 receptor agonist, inhibited Gsp-induced ISRs. Additionally, Gsp-induced ISRs were also suppressed by cyproheptadine, an antagonist of serotonin receptor. These findings suggest that Gsp-induced scratching might be at least partly mediated by capsaicin-sensitive primary afferents, and the opioids receptor systems might be involved in transmission of itch signaling in the central nervous system. Furthermore, our findings suggest that Gsp-induced ISRs may be attributable to the serotonin-mediated pathways and Gsp is not any more one of byproducts of abnormal skin barrier but can lead to induce pruritus, one of typical symptoms of atopic dermatitis.

• Korean Journal of Plant Resources
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• v.23 no.6
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• pp.513-518
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• 2010

In the present study, the antinociceptive profiles of Dianthus chinensis L extract were examined in ICR mice. Dianthus chinensis L extract administered orally (200 mg/kg) showed an antinociceptive effect as measured by the tail-flick and hot-plate tests. In addition, Dianthus chinensis L extract attenuated the writhing numbers in the acetic acid-induced writhing test. Furthermore, the cumulative nociceptive response time for intrathecal (i.t.) injection of substance P ($0.7\;{\mu}g$) was diminished by Dianthus chinensis L extract. Intraperitoneal (i.p.) pretreatment with yohimbine ($\alpha_2$-adrenergic receptor antagonist) attenuated antinociceptive effect induced by Dianthus chinensis L extract in the writhing test. However, naloxone (opioid receptor antagonist) or methysergide (5-HT serotonergic receptor antagonist) did not affect antinociception induced by Dianthus chinensis L extract in the writhing test. Our results suggest that Dianthus chinensis L extract shows an antinociceptive property in various pain models. Furthermore, this antinociceptive effect of Dianthus chinensis L extract may be mediated by $\alpha_2$-adrenergic receptor, but not opioidergic and serotonergic receptors.

• YAKHAK HOEJI
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• v.35 no.4
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• pp.326-331
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• 1991

Brain serotonin and its utilization was investigated on stressed rats after feeding high tryptophan diet for a month. High tryptophan fed rats displayed significantly higher level of serum tryptophan, brain tryptophan, serotonin (5-hydroxytryptamine; 5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) than the control diet fed rats. When rats were treated with 3 hour immobilization (IMMB) stress, serotonin turnover was slightly increased, but not statistically significant, in control diet group rats. However in high tryptophan diet rats, 3 hr IMMB stress resulted in statistically significantly (p<0.05) decreased the serum tryptophan, brain tryptophan and 5-HT level. The concentration of 5-HIAA was significantly increased indicating accelerated utilization of the brain 5-HT of the high trp. fed rat. The utilization pattern of the serotonin was found to be similar among young and adult rats. Rats on a tryptophan enriched diet displayed higher coping ability to the stress as they exhibited smaller increment of corticosterone level. A possble involvement of opioid system was suggested in serotonin utilization by measuring total $^{3}$[H]-naloxone binding in brain.