• Journal of Oriental Neuropsychiatry
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• v.18 no.1
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• pp.15-36
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• 2007

Objective : This study was to investigate the effects of several herbs on the levels of MT1 and MT2 melatonin receptors Methods: It was investigated the effects of several herbs such as WEDL, WEZV, WEFO, WEOC on the levels of MT1 and MT2 melatonin receptors using C6 glial cell model. ${\beta}-estradiol$ treatment, as a positive control group, under non-cytotoxic condition. Results : 1. The water extracts of Dimocarpus long (WEDL) induced the levels of MT2 melatonin receptor expression in a concentration-dependent manner without altering the levels of MT1 melatonin receptor expression. 2. The treatment with the water extract of Zizyphus vulgaris (WEZV) induced the levels of MT1 melatonin receptor expression and the levels of MT2 melatonin receptor expression was not affected. 3. The levels of MT1 as well as MT2 melatonin receptor expression were markedly up-regulated in the water extract of Fossilia ossis (WEFO) and the water extract of Ostreae caro (WEOC)-treated C6 cells. 4. The combination treatment with WEDL and WEZV induced not only the levels of MT1 melatonin receptor expression but also MT2 melatonin receptor expression, but the synergic effects of the combination treatment with WEFO and WEOC were not detected in C6 cells. Conclusion : The study provides important new insights into the possible mechanisms on the regulation of melatonin receptor synthesis by WEDL, WEZV, WEFO and WEOC.

• Journal of Oriental Neuropsychiatry
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• v.21 no.2
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• pp.103-123
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• 2010

Objectives : This study was to investigate the effect of several herbal prescriptions such as Tianwangbuxindan qu zhusha, Tianwangbuxindan, Wendantang, Guipitang on the level of $MT_1$ and $MT_2$ melatonin receptors in C6 glial cells. Methods : For this study, we exposed of C6 cells to several herbal prescriptions resulted in non-cytotoxic in various dose as measured by MTT assay, trypan blue count, morphology change and DAPI stain. Results : Tianwangbuxindan qu zhush and Tianwangbuxindan induced the levels of $MT_1$ melatonin receptor expression in a dose-dependent manner without altering the level of $MT_2$ melatonin receptor expression. However, the treatment with Wendantang, Guipitang don't effect of $MT_1$ and $MT_2$ melatonin receptor expression. Conclusions : This results suggest that Tianwangbuxindan can be a promising the regulation of melatonin receptor synthesis, and further studies will be needed to clarify the mechanism.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.2
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• pp.183-188
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• 2005

Two mammalian receptors are reported (MT1A and MT1B). In this experiments, MT1A is expressed at a little enhanced level (about 8 times) in hypothalamus of the 9 hours exposed mice. In other part of the brain, the expression level of the MT1A and MT1B is elevated at nearly same level: 16 times in cerebellum, 128 times in hippocampus and in thalamus, respectively. But MT1B is expressed at very high level (about thousand times) in hypothalamus of the 9 hours exposed mice.

• Biomolecules & Therapeutics
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• v.24 no.2
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• pp.115-122
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• 2016

Sleep, which is an essential part of human life, is modulated by neurotransmitter systems, including gamma-aminobutyric acid (GABA) and dopamine signaling. However, the mechanisms that initiate and maintain sleep remain obscure. In this study, we investigated the relationship between melatonin (MT) and dopamine D2-like receptor signaling in pentobarbital-induced sleep and the intracellular mechanisms of sleep maintenance in the cerebral cortex. In mice, pentobarbital-induced sleep was augmented by intraperitoneal administration of 30 mg/kg MT. To investigate the relationship between MT and D2-like receptors, we administered quinpirole, a D2-like receptor agonist, to MT- and pentobarbital-treated mice. Quinpirole (1 mg/kg, i.p.) increased the duration of MT-augmented sleep in mice. In addition, locomotor activity analysis showed that neither MT nor quinpirole produced sedative effects when administered alone. In order to understand the mechanisms underlying quinpirole-augmented sleep, we measured protein levels of mitogen-activated protein kinases (MAPKs) and cortical protein kinases related to MT signaling. Treatment with quinpirole or MT activated extracellular-signal-regulated kinase 1 and 2 (ERK1/2), p38 MAPK, and protein kinase C (PKC) in the cerebral cortex, while protein kinase A (PKA) activation was not altered significantly. Taken together, our results show that quinpirole increases the duration of MT-augmented sleep through ERK1/2, p38 MAPK, and PKC signaling. These findings suggest that modulation of D2-like receptors might enhance the effect of MT on sleep.