• Biomolecules & Therapeutics
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• v.5 no.1
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• pp.87-93
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• 1997

DA-5018, a new capsaicin derivative, showed potent analgesic effect comparable to that of morphine in various experimental acute pain models. in this study, whether the analgesic mechanism of DA-5018 is related to opiate receptors or prostanoids was investigated. The affinity of DA-5018 for opiate receptor was determined by receptor binding assay. The Ki values of DA-5018 for nonspecific and specific $\mu$, $textsc{k}$, $\delta$-opiate receptor was 299$\pm$8.88, 735$\pm$215, 2930$\pm$ 163, 1550$\pm$813 nM, respectively and DA-5018 exhibited lower affinity than morphine. DA-5018 (10-"~3$\times$10-′M) inhibited electrically-evoked contractions of the guinea ply ileum and rat vas deferens, and these inhibition was not antagonized by naloxone(10 nM), an opiate receptor antagonist. Antagonism of analgesic effect of 7A-5018 by naloxone was examined by tail pinch test. Analgesic action of DA-5018(0.1 ~2 mg/kg, 5.c.) was not antagonized by naloxone(1 mg/rg, i.p.). These results indicate that pharmacological action of DA-5018 is not related with opiate receptor. Cyclooxygenase and 5-lipoxygenase activities in rat peritoneal neutrophil treated with A23187 and arachidonic acid were measured by radioimmunoassay. DA-5018 stimulated the cyclooxygenase activity and the concentration show-ing the two fold increase of activity was 124$\mu$M. DA-5018 slightly inhibited 5-lipoxygenase activity and these results together indicate that analgesic action of 3A-5018 is not mediated through inhibition of cyclooxy genase or lipoxygenase. These results suggest that the analgesic effect of DA-5018 is not due to blocking opiate receptor or to inhibiting the synthesis of prostanoids in the arachidonic acid metabolism pathway.

• The Journal of Internal Korean Medicine
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• v.26 no.4
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• pp.864-874
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• 2005

This study was done as a general survey on oriental medical approaches for the detoxification and treatment of narcotics addiction. The treatment of narcotics addiction comprises the detoxification and the restoration of normal health. Medical detoxification in common use nowadays is largely divided into substitution therapy using opiate detoxicants and symptomatic therapy using non-opiate detoxicants. Experimentation was done on the supposition that non-opiate detoxicants provide a more viable therapy than opiate detoxicants in the treatment of narcotics addiction, because opiate detoxicants also produce a great dependency on a narcotic. At present, although the medication of oriental medicine that includes non-opiate detoxicants is not more effective in the detoxification than the opiate detoxicants, withdrawal symptoms are slight and few and there is a very low ratio of relapse, so treatment and restoration are relatively brief. Results of this survey suggest that detoxicants derived from oriental medical approaches are safe and effective, though further development of therapy with such detoxicants will be needed to provide reliable methods of treating narcotics addiction. Based on this survey, it is hoped that many more studies will be done on the issue of medication in the field of narcotics addiction treatment.

• The Korean Journal of Pharmacology
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• v.22 no.2
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• pp.88-95
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• 1986

Clinically, subhypnotic doses of barbiturates have been known to elicit hyperalgesia. In this experiment, effect of acute or chronic phenobarital treatment on the response to pain in rat was reevaluated by hot-plate method. To elucidate its mechanism, changes of ${\beta}-endorphin$ contents and [3H]-morphine binding of the rat midbrain as well as functional opiate receptor in vas deferens were also measured. Intraperitoneal injection of sub anesthetic dose phenobarbital induced initial hyperalgesia followed by successive analgesia, while chronic phenobarbital-treatment decreased reactivity to pain. Naloxone (10mg/kg, i.p.) markedly shortened hot plate latency period, and significantly inhibited the analgesic action of phenobarbital. Single dose of phenobarbital did not affect ${\beta}-endorphin$ contents and [3H]-morphine binding in rat mid brain, but in the chronic phenobarbital-treated groups, ${\beta}-endorphin$ contents was increased, while Bmax of opiate receptor binding was decreased. Moreover, very significant correlations among responses to pain, changes of ${\beta}-endorphin$ contents and opiate receptor binding were observed. However, Kd values of opiate receptor bindings were not changed in all preparations. In the chronic phenobarbital-treated vas deferens preparations, ID50 of morphine was increased witb concomittant decrease of maximum effect. But $pA_2 $, value for naloxone was not changed. From these results, it is suggested that phenobarbital can produce analgesia due to changes of ${\beta}-endorphin$ contents as well as functional opiate receptors by receptor regulation.

• The Korean Journal of Pharmacology
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• v.20 no.2
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• pp.23-34
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• 1984

To investigate diurnal variations of opiate receptor binding and its modification by experimental condition or treatment of various centrally-acting drugs, the amount of maximum $^3H-morphine$ binding in rat midbrain homogenates was measured at 4 hour intervals for 24 hours. Animals were conditioned under the controlled L : D, 12 : 12 cycle or D: D, 12 : 12 cycle, for 3 weeks and treated with 0.5 ml of physiological saline or drugs for 2 weeks. A highly significant diurnal rhythm with peak at 22 hour of early dark phase with an amplitude$(0.68{\pm}0.06\;pmole/mg\;protein)$ of +51.1% and nadir $(0.33{\pm}0.03\;mole/mg\;prtein)$ at 18 hour of late light phase with an amplitude of -26.6% was found in control group. 24 tour mean of $^3H-morphine$ binding was $0.45{\pm}0.03\;pmole/mg$ protein respectively. Constant dark adaptation or treatment of reserpine, pargyline, imipramine, amphetamine and chlorpromazine modified the diurnal rhythm in the time of peak and nadir binding shape, phase, amplitude of the diurnal curve and 24 hour mean of $^3H-morphine$ binding. However, Kd values were not changed in all experimental groups : Statistical analysis at times of least and great binding indicates that the differences in $^3H-morphine$ binding were due to changes not in the affinity, but in the number of binding sites. The results are interpreted with regard to the diurnal rhythm of opiate receptor finding. The modes of action of psychoactive drugs are closely related to postulated changes of receptor sensitivity in neuropharmacological aspects.

• The Korean Journal of Pharmacology
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• v.21 no.2
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• pp.128-141
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• 1985

To investigate the influence of phenobarbital sodium on the action of morphine and on the diurnal rhythms of both opiate receptor binding and ${\beta}-endorphin$ contents, the amount of specifically bound $(^3H)$-morphine and immunoreactive ${\beta}-endorphin$ were measured in the midbrain of phenobarbital-treated rats at 4h intervals in a day. Rats were housed and adapted to a controlled cycle of either 12 h light-12 h dark or 24 h constant dark. After 3 weeks of adaptation, 0.5 ml of physiological saline or phenobarbital sodium (20mg/kg/day, i.p.) were administered twice a day for 2 weeks. Highly significant diurnal rhythms of opiate receptor binding and ${\beta}-endorphin$ were present in rat midbrain. In control group, the peak of maximum $(^3H)$-morphine binding was observed at 22:00 h, whereas the peak of ${\beta}-endorphin$ content was found at 06:00 h. Even in the absence of time cues these diurnal rhythms persisted, but they were highly modified with respect to the wave form as well as differences in the timing of peak and nadir. In the phenobarbital-treated group, these diurnal rhythms were also modified in shape, phase and amplitude, as well as in timing of peak and nadir. In this group, 24 h mean of opiate receptor binding was significantly decreased, while the 24 h mean level of ${\beta}-endorphin$ content was highly increased. However, Kd values in all experimental groups did not change. This indicates that differences in binding were not due to changes in the affinity, but in the number of binding sites. Statistical analysis of regression line indicates that changes of receptor binding were closely correlated with the changes of ${\beta}-endorphin$ content. These results suggest that phenobarbital may influence the action of morphine by changing the number of opiate receptors and that the modification of diurnal rhythm of opiate receptor by the agent is possibly due to changes of ${\beta}-endorphin$ content.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1992.05a
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• pp.40-40
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• 1992

opiate receptor들의 중추신경계에서의 분포 및 작용에 관한 실험물은 널리 알려져 있어 그 웅용 방법도 많이 있으나, 말초에 있는 opiate receptor의 존재 및 약물작용을 관찰하는 실험은 별로 알려진 것은 없다. 저자는 214mM의 sucrose 용역을 이용하여 전기적 자극에 따른 말초신경 및 말초조직(근육)에서의 opiate receptor애 대한 작용을 관찰하였다. 실험은 3분류의 약물을 이용하였다. 1) Pure agonists: morphine, meperidine, methadone, 2) Agonist-antagonist: buprenorphine 3) Pure antagonist: naloxone 위의 약물들을 이용하여 excitable cell membrane(좌골신경 및 근육)에서 일어나는 potential의 변화를 관찰하여 다음과 같은 결과를 얻었다. a. pure agonists들은 좌골신경 및 근육절편에서 action potentials을 의의있게 억제시켰으며 meperidine이 가장 강한 작용을 보였다. b. 이들의 작용은 naloxone 투여로 억제되었다. c. Agonist-antagonist인 buprenorphine은 투여용량 및 동시 투여한 pure agonist의 종류에 따라 biphasic pattern을 나타내었다. d. opiates 작용기전 및 약물작용장소를 알고자 두 종류, 즉 single 및 double technique을 사용하여 비교하였다.

• Journal of Nutrition and Health
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• v.17 no.4
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• pp.313-319
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• 1984

The effect of morphine on food intake on freely fed Sprague - Dawley rats was examined Opiate receptor binding assay was used to investigate the possibility of the opioid system involved in food intake regulation of normal rats. When rats were treated with 5mg morphine per kg body weight, subcutaneously, the food intake of the rats for the first 2 hours was increased 125% of the control rats. The effect of morphine on food intake of male and female rats were greater when the morphine was injected at 10 : 00 a.m than that in the rats administered the morphine at 4 : 00 p.m. The morphine effect was not significant in older rats and female was more responsive than male rats. In morphine treated rats, opioid receptor density has exhibited 33% reduction as measured by the $^{3}H-naloxone$ binding assay with whole brain homogenate. These results indicate that the increase of food intake by morphine for 2 hours after the injection may be mediated through the opioid system in rat brain.

• The Korean Journal of Pharmacology
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• v.23 no.2
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• pp.123-131
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• 1987

The possible inolvement of central opiate system in the control of cardiovascular function and in the antihypertensive action of clonidine has been examined in unanesthetized rats with shamoperated or 2-kidney, 1-clip (2K1C) renal hypertension. In both groups of rats, intraventricular clonidine $(3-30\;{\mu}g/kg)$ produced hypotension and bradycardia. Hypotensive action of clonidine was more potent in the hypertensive rats than in the normotensive sham-operated rats. Yohimbine $(30\;{\mu}g/kg,\;i.v.t.)$ inhibited the hypotension and bradycardia produced by clonidine. Naloxone ($50\;{\mu}g/kg$, i.v.t.) inhibited the action of clonidine in 2K1C hypertensive rats but not influenced in the sham-operated rats. Intraventricular morphine $(10-100\;{\mu}g/kg)$ also reduced rats. Intraventricular morphine $(10-100\;{\mu}g/kg)$ also reduced blood pressure and heart rate in both groups of rats. But these effects were not affected by yohimbine, but antagonized by naloxone ($50\;{\mu}g/kg$, i.v.t.). Chronic treatment of 2K1C rats with clonidine ($3{\times}20\;{\mu}g/kg$, p.o.,) for 14 days from 1 day after 2K1C operation) suppressed the development of hypertension and maintained the blood pressure in normal level and this errect of clonidine was abolished by naloxone (2 mg/kg, i. p.). In the 2K1C hypertensive rats, immunoreactive ${\beta}-endorphin$ content was significantly decreased, but maximum binding (Bmax) of $(^3H)-naloxone$ was significantly increased in brain of 2K1C hypertensive rats. However, Kd value was not changed. These results suggest that the opioidergic component might be involved in the antihypertensive action of clonidine only in hypertensive and that central opiate system might play important roles in pathophysiology of development and maintenance of hypertension.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.6
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• pp.691-697
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• 1997

The mechanisms underlying opiate tolerance and dependence are not fully understood. We used human neuroblastoma SH-SY5Y cells as a model system for studying effects of morphine tolerance and withdrawal on c-myc induction and cAMP levels. It has been reported that regulation of c-fos by acute and chronic morphine withdrawal is mediated through alterations in CREB transcription factor. In this study, we examined the effects of morphine tolerance on c-myc expression and cAMP concentrations. The activation of opiate receptors by an acute morphine administration resulted in an increase in c-myc mRNA and a decrease in cAMP concentrations in a dose-dependent manner $(5,\;10,\;15,\;and\;20\;{\mu}M)$. On the other hand, the chronic treatment of morphine $(10\;{\mu}M\;for\;six\;days)$ did not induce the elevated expression of c-myc mRNA. The c-myc expression was slightly inhibited in comparison with that of the acute morphine response. However, cAMP concentrations were increased with regard to morphine withdrawal response. These results suggest that the alterations in c-myc expression might imply a significant opiate regulation relating to morphine tolerance. This observation differs from increased expression of c-fos via regulation of cAMP pathway.

• The Korean Journal of Pharmacology
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• v.28 no.2
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• pp.181-190
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• 1992

The present study was conducted to investigate the effect of opioids on catecholamine (CA) secretion evoked by a selective cholinergic nicotinic agonist, 1,1-dimethyl-4-phenyl piperazinium (DMPP) and acetylcholine from the retrogradely perfused rat adrenal glands. Methionine-enkephalin $(9.68{\times}10^{-6}\;M)$ caused a significant inhibition of CA secretion evoked by DMPP (100 uM) and $ACh\;(50\;{\mu}g)$, but had no effect on the spontaneous (basal) CA release. Morphine $(1.73{\times}10^{-5}\;M)$ attenuated considerablely the increase in CA release induced by DMPP and ACh. Morphine itself also did not affect the basal CA output. A 20 to 65% reduction of the DMPP- and ACh-evoked increase in CA release was observed after the pretreatment with methionine-enkephalin or morphine. The increase in CA release evoked by DMPP and ACh was reduced markedly by preloading with an opiate antagonist naloxone $(1.22{\times}10^{-7}\;M)$ while basal CA output was not affected by naloxone. These present experimental results suggest that the nicotinic stimulation-evoked CA release from the perfused rat adrenal gland is inhibited by endogenously released opioid peptides through activation of opiate receptors located in the adrenal gland.