• 수면정신생리
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• 제25권1호
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• pp.5-8
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• 2018

Restless legs syndrome (RLS) is a sleep disorder characterized by an urge to move the legs or arms and uncomfortable paresthesia in the legs. Treatment of RLS can be various depending on the causes, severity, and frequency of the symptoms. In the case of secondary RLS, it is important to identify and manage the cause of RLS. Dopamine agonists have been used as firstline treatments for primary RLS treatment. However, due to augmentation, which is a common side effect of dopamine agonists, recent treatment guidelines are changing to prefer to anticonvulsants such as pregabalin and gabapentin. Iron, opioid, or benzodiazepine may be used when anticonvulsants or dopamine agonists are not adequately treated. Because RLS is a chronic disease, it is essential to establish a long-term treatment plan considering both efficacy and side effects.

• Archives of Pharmacal Research
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• 제25권2호
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• pp.202-207
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• 2002

This study was performed to investigate the effect of tetrahydroisoxazolopyridine (THIP), a $GABA_A$ agonist, on the morphine-induced hyperactivity, reverse tolerance and postsynaptic dopamine receptor supersensitivity in mice. A single administration of morphine induced hyperactivity in mice. However, the morphine-induced hyperactivity was inhibited dose-dependently by the administration of THIP (0.2, 0.4 and 0.8 mg/kg, i.p.). In contrast, daily administration of morphine resulted in a reverse tolerance to the hyperactivity caused by morphine (10 mg/kg ,s.c.). THIP inhibited the development of reverse tolerance in the mice that had received the repeated same morphine (10 mg/kg s.c.) doses. The postsynaptic dopamine receptor supersensitivity, which was evidenced by the enhanced ambulatory activity its after the administration of apomorphine (2 mg/kg s.c.), also developed in the reverse tolerant mice. THIP also inhibited the development of the postsynaptic dopamine receptor supersensitivity indulged by the chronic morphine administration. These results suggest that the hyperactivity, reverse toterance and postsynaptic dopamine receptor supersensitivity induced by morphine can be inhibited activating the $GABA_A$ receptors.

• Clinical and Experimental Reproductive Medicine
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• 제26권2호
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• pp.287-291
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• 1999

Dopamine agonists are commonly used in the medical treatment of prolactinomas. Bromocriptine has been the most widely used ergot derivative for two decades. Its oral administration, at a daily dose of $2.5{\sim}7.5mg$, restored normal gonadal function and normoprolactinemia in about 80% of patients. Nevertheless, a subset of patients could not achieve normal prolactin levels or resume normal gonadal function despite $15{\sim}30mg$/day bromocriptine for at least 6 months. Subsequently, these prolactinomas were consedered to be resistant to bromocriptine. The percentage of bromocriptine - resistant prolactinoma patients reported in the literature varies between 5 and 17% according to the series. Patients with bromocriptine resistance or bromocriptine intolerance have, however, been treated with other dopamine agonists, such as lysuride, pergolide, cabergoline, or quinagolide. Until cabergoline recently gained a product licence in the UK, there was no alternative dopamine agonist with a licence for this purpose. Quinagolide (CV $205{\sim}502$, Norprolac, Sandoz) is a nonergot dopamine agonist with improved selectivity for the D2 receptor, designed to retain the active pharmacophore of bromocriptine without the ergot moiety that might be responsible for side - effects. We have experienced a case of bromocriptine resistant hyperprolactinemia which was reponsive to pergolide. So we report this case with a brief review of literatures.

• Biomolecules & Therapeutics
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• 제14권3호
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• pp.125-131
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• 2006

The inhibitory effects of (-)-epigallocatechin gallate (EGCG), a major compound of green tea, on the development of locomotor sensitization, conditioned place preference (CPP) and dopamine receptor supersensitivity induced by the repeated administration of morphine were investigated in mice. A single administration of morphine produces hyperlocomotion. The repeated administration of morphine develops sensitization, a progressive enhancement of locomotion, which is used as a model for studying the craving and drug-seeking behaviors characterizing addiction, and CPP, which is used as a model for studying drug reinforcement, respectively. EGCG inhibited morphine-induced hyperlocomotion, sensitization and CPP. In addition, EGCG inhibited the development of postsynaptic dopamine receptors supersensitivity, which may be an underlying common mechanism that mediates the morphine-induced dopaminergic behaviors such as sensitization and CPP. Apomorphine (a dopamine agonist)-induced climbing behaviors also were inhibited by a single direct administration of EGCG These results provide evidence that EGCG has anti-dopaminergic activity, as inhibiting the development of dopamine receptor supersensitivity and apomorphine-induced climbing behaviors. Therefore, it is suggested that green tea may be useful for the prevention and therapy of these adverse actions of morphine.

• Biomolecules & Therapeutics
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• 제27권6호
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• pp.514-521
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• 2019

G protein-coupled receptors (GPCRs) are membrane receptors whose agonist-induced dynamic conformational changes trigger heterotrimeric G protein activation, followed by GRK-mediated phosphorylation and arrestin-mediated desensitization. Cytosolic regions of GPCRs have been studied extensively because they are direct contact sites with G proteins, GRKs, and arrestins. Among various cytosolic regions, the role of helix 8 is least understood, although a few studies have suggested that it is involved in G protein activation, receptor localization, and/or internalization. In the present study, we investigated the role of helix 8 in dopamine receptor signaling focusing on dopamine D1 receptor (D1R) and dopamine D2 receptor (D2R). D1R couples exclusively to Gs, whereas D2R couples exclusively to Gi. Bioinformatic analysis implied that the sequences of helix 8 may affect GPCR-G protein coupling selectivity; therefore, we evaluated if swapping helix 8 between D1R and D2R changed G protein selectivity. Our results suggest that helix 8 is not involved in D1R-Gs or D2R-Gi coupling selectivity. Instead, we observed that D1R with D2R helix 8 or D1R with an increased number of hydrophobic residues in helix 8 relative to wild-type showed diminished ${\beta}$-arrestin-mediated desensitization, resulting in increased Gs signaling.

• 생물정신의학
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• 제6권2호
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• pp.193-201
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• 1999

This study was designed to evaluate the effects of opioid receptor agonists on the spontaneous alternation behaviour in an animal model of obsessivecompulsive disorder in rats. According to the theory that dopamine is related to the biological etiology of obsessive-compulsive disorder, the effect of the nalbuphine(opioid kappa agonist) and the tramadol(opioid mu agonist), which act as manipulating agents on the inhibition or stimulation of dopamine release, in the spontaneous alternation behaviour were evaluated. 24 hours prior to the experiment, rats were food-deprived. These rats were put into the T-maze, in which white and black goal boxes were baited with small amounts of chocolate milk. Each rat was given 2 set of 7 trials during which it was placed in the start box and allowed to choose the one of the goal boxes for each time. After identifying the stable baseline of spontaneous alternation behaviour, nonselective 5-HT agonist 5-MeODMT(1.25mg/kg/IP) disrupted spontaneous alternation. Rats were stratified into fluoxetine(10mg/kg/IP), nalbuphine(10mg/kg/IP), tramadol(46.4mg/kg/IP), and saline(0.5cc/IP) injection group with experimental drug treatment for 21 days. The effects on the 5-MeODMT(1.25mg/kg/IP) induced disruption of spontaneous alternation behaviour were checked at the next day of discontinuation of drug treatment. The results were as follows ; 1) At the day after 21 days of the drug treatment, the nalbuphine treated group and the fluoxetine treated group showed significant difference from the tramadol treated group and the saline treated group in the 5-MeODMT(1.25mg/kg/IP) induced suppression of spontaneous alternation behaviour. 2) Within each drug treatment group, the fluoxetine treated group showed significant difference between before and after the treatment of fluoxetine in the 5-MeODMT(1.25mg/kg/IP) induced suppression of spontaneous alternation behaviour. And also, the nalbuphine treated group showed significant difference between before and after the treatment of nalbuphine in the 5-MeODMT(1.25mg/kg/IP) induced suppression of spontaneous alternation behaviour. There was no difference between the baseline and after the treatment of nalbuphine in the 5-MeODMT(1.25mg/kg/IP) induced suppression of spontaneous alternation behaviour. We indentified that the opioid kappa agonist that act as dopamine release inhibitor affect the spontaneous alternation behaviour which is an animal model of obsessive-compulsive disorder in rat.

• Archives of Pharmacal Research
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• 제29권10호
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• pp.904-910
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• 2006

The inhibitory effects of paeonol, a major compound of Paeoniae radix, on the development of locomotor sensitization, conditioned place preference (CPP) and dopamine receptor supersensitivity induced by the repeated administration of morphine were investigated through behavioral experiments. A single administration of morphine produces hyperlocomotion. Repeated administration of morphine develops sensitization (reverse tolerance), a progressive enhancement of locomotion, which is used as a model for studying the drug-induced drug-seeking behaviors, and CPP, which is used as a model for studying drug reinforcement. Paeonol inhibited morphine-induced hyperlocomotion, sensitization and CPP. In addition, paeonol inhibited the development of postsynaptic dopamine receptors supersensitivity, which may be an underlying common mechanism that mediates the morphine-induced dopaminergic behaviors such as sensitization and CPP. Apomorphine (a dopamine agonist)-induced climbing behaviors also were inhibited by a single direct administration of paeonol. These results provide evidence that paeonol exerts anti-dopaminergic activity, and it is suggested that paeonol may be useful for the prevention and therapy of these adverse actions of morphine.

• 대한약리학회지
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• 제28권1호
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• pp.19-25
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• 1992

Nonbenzodiazepine계 항불안제인 buspirone을 이용하여 건강한 8명의 남자를 대상으로 prolactin과 cortisol분비를 측정하였다. Buspirone는 $Dopamine_2$ 수용체 antagonist 성질 뿐 아니라 $5-HT_{1A}$ partial agonist 효과가 있는 것으로 보고되고 있다. Buspirone 30mg 경구투여시 혈청 prolactin 농도는 유의한 증가를 보였으나 혈청 cortisol 농도의 변화는 차이가 없었다. beta adrenoreceptor antagonist이면서 $5-HT_{1A}$ 수용체 antagonist로 알려진 pindolol (30mg)을 경구 투여한 결과 기초 혈청 prolactin이나 cortisol 농도는 유의한 차이가 없었다. Pinodlol을 전처치한 경우 buspirone-induced prolaction 분비의 유의한 억제효과는 없었다. 이상의 성적은 buspirone-induced prolactin 분비증가는 아마도 $5-HT_{1A}$ 수용체 활성과 관련되지 않음을 시사하는 것으로 사료된다.

• The Korean Journal of Physiology and Pharmacology
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• 제9권5호
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• pp.263-268
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• 2005

Striatum has important roles in motor control, habitual learning and memory. It receives glutamatergic inputs from neocortex and thalamus, and dopaminergic inputs from substantia nigra. We examined effects of dopamine (DA) on the corticostriatal synaptic transmission using in vitro extracellular recording technique in rat brain corticostriatal slices. Synaptic responses were elicited by stimulation of cortical glutamatergic inputs on the corpus callosum and recorded in the dorsal striatum. Corticostriatal population spike (PS) amplitudes were decreased ($39.4{\pm}7.9$%) by the application of $100{\mu}M$ DA. We applied receptor subtype specific agonists and antagonists and characterized the modulation of corticostriatal synaptic transmission by different DA receptor subtypes. $D_2$ receptor agonist (quinpirole), antagonist (sulpiride), and $D_1$ receptor antagonist (SKF 83566), but not $D_1$ receptor agonist (SKF 38393), induced significantly the reduction of striatal PS. Pretreatment neither with SKF 83566 nor sulpiride significantly affected corticostriatal synaptic inhibition by DA. However, the inhibition of DA was completely blocked by pretreatment with mixed solution of both SKF 83566 and sulpiride. These results suggest that DA inhibits corticostriatal synaptic transmission through both $D_1$ and $D_2$ receptors in concert with each other.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1996년도 춘계학술대회
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• pp.214-214
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• 1996

Intraperitoneal injection of morphine (5 mg/kg) in mice every other day for 8 days produced conditioned place preference (CPP). CPP effects were evaluated by assessing the difference in time spent in the drug-paired compartment and the saline-paired compartment of the place conditioning apparatus. The injection of a non-competitive NMDA antagonist, MK-801 (0.05 and 0.1 mg/kg, i.p.), prior to and during morphine treatment in mice Inhibited morphine-induced CPP. The development of postsynaptic dopamine (DA) receptor supersensitivity in mice displaying a morphine-induced CPP was evidenced by the enhanced response in ambulatory activity to the DA agonist, apomorphine (2 mg/kg). MK-801 inhibited that development of postsynaptic DA receptor supersensitivity MK-801 also inhibited apomorphine-induced climbing behavior, suggesting that MK-801 Inhibits dopaminergic activation mediated via the NMDA receptor.