• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.123-123
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• 2018

Premenstrual syndrome (PMS) is a common disorder affecting the emotional and physical health of women during certain periods of the menstrual cycle. Many researchers who have previously studied PMS have believed that PMS is associated with changes in sex hormones and serotonin levels at the beginning of the menstrual cycle. However, recent studies suggest that progesterone/estrogen imbalance and elevation of prolactin-induced by dopamine low-secretion play a crucial role in increasing PMS symptoms. Because of this, we have focused on mitigating PMS symptoms through the mechanism of prolactin secretion inhibition by dopamine receptor activation. The inhibition of prolactin secretion by 61-kinds of medicinal herb extracts was investigated in GH3 pituitary cells. Among them, Inula heleniun L. root extract (IHE) showed excellent prolactin secretion inhibitory effect. IHEs were prepared using 30, 50, and 70% ethanol. And the yield, cytotoxicity, dopamine receptor activity and inhibition of prolactin secretion of each extract were measured. Through a series of experiments, we found that prolactin secretion was significantly reduced (P<0.01) by the components present in IHE and that dopamine receptor regulation was possible (P<0.05). Considering yield and safety, we suggest the use of 30% ethanol IHE in the development of PMS symptom relief products.

• Korean Journal of Pharmacognosy
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• v.16 no.1
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• pp.31-35
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• 1985

Intraperitoneal administration of ginseng butanol fraction(GBF) to chronic morphinization in male Sprague-Dawley rats inhibited the development of tolerance to the analgesic effect and hyperthermic action of morphine. Rats were rendered tolerant to morphine by subcutaneous multiple morphine injections for a period of 8 days. The development of tolerance was evidenced by the decreased analgesic response to morphine and inhibition of tolerance by the greater analgesic response. Concomitant administration of morphine with GBF blocked the tolerance to the hyperthermic effect of morphine as evidenced by elevation of body temperature by morphine. Dopamine receptor sensitivity was enhanced in morphine tolerant rats as measured by apomorphine induced in spontaneous motor activity. GBF administration also blocked dopamine receptor supersensitivity induced by chronic morphinization.

• Biomolecules & Therapeutics
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• v.14 no.3
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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.

• Analytical Science and Technology
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• v.8 no.3
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• pp.365-370
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• 1995

A tissue biosensor for the measurement of dopamine has been constructed by immobilizing the slice of Sprague-Dawley rat liver on $NH_3$-sensing electrode. To overcome the defect of tissue sensors, the maximal velocity of response curve was measured and applied to the Lineweaver-Burk equation instead of the Nernst equation. And then compared the results with those obtained from Nernst equation. When we obtained calibration curves from Nernst equation, there were variances on the slope and the linear range. But from Lineweaver-Burk equation, the scale of variance was small. Response time was reduced from 7~12 minutes to 2~3 minutes.

• Archives of Pharmacal Research
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• v.26 no.12
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• pp.1074-1078
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• 2003

The effects of glycine on morphine-induced hyperactivity, reverse tolerance and postsynaptic dopamine receptor supersensitivity in mice was examined. A single administration of morphine (10 mg/kg, s.c.) induced hyperactivity as measured in mice. The morphine-induced hyperactivity was inhibited by pretreatment with glycine (100, 200 and 400 mg/kg, i.p.). In addition, it was found repeated administration of morphine (10 mg/kg, s.c.) to mice daily for 6 days caused an increase in motor activity which could be induced by a subsequent morphine dose, an effect known as reverse tolerance or sensitization. Glycine (100, 200 and 400 rng/kg, i.p.) also inhibited morphine-induced reverse tolerance. Mice that had received 7 daily repeated administrations of morphine also developed postsynaptic dopamine receptor supersensitivity, as shown by enhanced ambulatory activity after administration of apomorphine (2 mg/kg, s.c.). Glycine inhibited the development of postsynaptic dopamine receptor supersensitivity induced by repeated administration of morphine. It is suggested that the inhibitory effects of glycine might be mediated by dopaminergic (DAergic) transmission. Accordingly, the inhibition by glycine of the morphine-induced hyperactivity, reverse tolerance and dopamine receptor supersensitivity suggests that glycine might be useful for the treatment of morphine addiction.

• YAKHAK HOEJI
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• v.47 no.4
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• pp.230-233
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• 2003

Previously, protoberberine alkaloids such as berberine and palmatine have been found to lower dopamine content in PC12 cells (Shin et at., 2000). In this study, the effects of berberine and palmatine on L-DOPA-induced increase in dopamine level and cytotoxicity in PC12 cells were investigated. Treatment of PC12 with L-DOPA at concentration ranges of 20∼50 $\mu$M increased dopamine content and the increase in dopamine levels by L-DOPA was inhibited by 10∼40 $\mu$M berberine and 10∼80 $\mu$M palmatine, which the concentration ranges did not show a cytotoxicity. However, berberine and palmatine at concentrations higher than 50 $\mu$M and 100 $\mu$M caused a cytotoxicity, respectively. In addition, berberine (10∼20 $\mu$M) and palmatine (10∼50 $\mu$M) at non-cytotoxic concentration ranges aggravated L-DOPA-induced cytotoxicity in PC12 cells (L-DOPA concentration ranges, 20∼50 $\mu$M). The L-DOPA-induced cytotoxicity was also significantly potentiated by berberine (50 $\mu$M) and palmatine (100 $\mu$M) with cytotoxic ranges. These data demonstrate that berberine and palmatine inhibit L-DOPA-induced increase in dopamine content and stimulate L-DOPA-induced neurotoxicity. Therefore, the possibility that the long-term L-DOPA treated patients with berberine and palmatine could be checked the adverse symptoms.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.2
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• pp.118-131
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• 2007

Neurotransmitter imaging with radiopharmaceuticals plays major role for understanding of neurological and psychiatric disorders such as Parkinson's disease and depression. Radiopharmaceuticals for neurotransmitter imaging can be divided to dopamine transporter imaging radiopharmaceuticals and serotonin trnasporter imaging radiopharmaceuticals. Many kinds of new dopamine transporter imaging radiopharmcaeuticals has a tropane ring and they showed different biological properties according to the substituted functional group on tropane ring. After the first clinical trials with $[^{123}I]{\beta}-CIT$, alkyl chain substituent introduced to tropane ring amine to decrease time for imaging acquisition and to increase selectivity. From these results, $[^{123}I]PE2I$, [18F]FE-CNT, $[^{123}I]FP-CIT$ and $[^{18}F]FP-CIT$ were developed and they showed high uptake on the dopamine transporter rich regions and fast peak uptake equilibrium time within 4 hours after injection. $[^{11}C]McN$ 5652 was developed for serotonin trnasporter imaging but this compound showed slow kinetics and high background radioactivity. To overcome these problems, new diarylsulfide backbone derivatives such as ADAM, ODAM, AFM, and DASB were developed. In these candidates, $[^{11}C]AFM$ and $[^{11}C]DASB$ showed high binding affinity to serotonin transporter and fast in vivo kinetics. This paper gives an overview of current status on dopamine and serotonin transporter imaging radiopharmaceuitcals and the development of new lead compounds as potential radiopharmaceuticals by medicinal chemistry.

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.5
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• pp.1149-1154
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• 2006

Repeated administration of all addictive drugs, including nicotine, can produce sensitization of extracellular dopamine levels in the nucleus accumbens and behavioral sensitization in rat, as evidenced by an enhanced locomotor response and increased dopamine release in brain to a subsequent injection of the drug. In order to investigate the effect of Zizyphus jujuba extract on repeated nicotin-induced sensitization, rats were given repeated injection of saline or nicotine (0.4 mg/kg s.c., twice a day for 7 d), followed by one challenge injection on the 4th day after the last daily injection. Systemic challenge with nicotine (0.4 mg/kg s.c.) and a direct local challenge of 3 mM a larger increase in locomotor activity and extracellular dopamine release in the nucleus accumbens in nicotine-pretreated rats than in saline-pretreated rats, respectively. Zizyphus jujuba extract significantly decreases locomotor activitiy and dopamine release in the nucleus accumbens induced by a nicotine challenge. These results suggest that Zizyphus jujuba extract may attenuate nicotine-induced neurochemical and behavioral sensitization and may be effective in suppressing compulsive nicotine-seeking behavior.

• Biomolecules & Therapeutics
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• v.27 no.6
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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.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.2
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• pp.158-165
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• 2007

Technological advances in molecular imaging made it possible to image synaptic neurotransmitter concentration in living human brain. The dopaminergic system has been most intensively studied because of its importance in neurological as well as psychiatric disorders. This paper provides a brief overview of recent progress in imaging studies of dopamine release induced by pharmacologic and nonpharmacologic stimulations.