• Biomolecules & Therapeutics
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• 제9권3호
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• pp.201-208
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• 2001

The present study was conducted to examine the effects of cholinergic stimulation and membrane depolarization on secretion of epinephrine (EP) and norepinephrine (NE) in the perfused model of the rat adrenal gland and to investigate the effect of bromocriptine on secretion of EP and NE evoked by these secreta-gogues. Acetylcholine (ACh, 5.32 mM), high $K^{+}$(56mM), 1.1-dimethyl-4-phenyl piperazinium iodide (DMPP, 100 $\mu$M for 2 min), (3-(m-cholro-phenyl-carbamoyl-oxy)-2butynyl trimethyl ammonium chloride (McN-A-343, 100 $\mu$M for 2 min), cyclopiazonic acid (10 $\mu$M for 4 min) and methyl-1,4-dihydro-2,6-dimethyl-3-nitro-4-(2-trifluoromethylphenyl) -pyridine-5-carboxylate (Bay-K-8644, 10 $\mu$M for 4 min) evoked a 1.3~5.3-fold greater secretion of EP than NE in the perfused rat adrenal gland. The perfusion of bromocriptine (1-10 $\mu$M) into an adrenal vein for 20 min produced relatively dose-dependent inhibition in secretion of EP and NE evoked by ACh, high $K^{+}$, DMPP, and McN-A-343. Moreover, under the presence of bromocriptine (1~10 $\mu$M), releasing responses of EP and NE evoked by cyclopiazonic acid and Bay-K-8644 were also greatly reduced. Taken together, these results suggest that cholinergic stimulation and membrane depolarization enhance more release of EP than NE in the perfumed rat adrenal medulla, and that bromocriptine inhibits the release of EP and NE evoked by stimulation of cholinergic receptors as well as by membrane depolarization. It seems that this inhibitory effect of bromocriptine is associated with inhibition of calcium channels through activation of dopaminergic D2-receptors located in the rat adrenomedullary chromaffin cells.lls.

• 동의신경정신과학회지
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• 제20권1호
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• pp.21-42
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• 2009

Objectives : This Study was performed to assess the antioxidant and neuroprotective effect of Chunghyul-dan(Qingxuedan) in PC12 cells and primary rat mesencephalic dopaminergic neurons. Methods : The anioxidant effect was investigated using the DPPH radical and ABTS cation scavenging assays and total polyphenol amout of Chunghyul-dan(Qingxuedan). The neuroprotective effect of Chunghyul-dan(Qingxuedan) in PC12 cells was evaluated using MTT assay. The scavenging activity of Chunghyul-dan(Qingxuedan) on ROS production induced by 6-OHDA(6-hydroxydopamine) in PC12 cells was evaluated, as well as the attenuating effect on GSH reduction. Finally, we examined the neuroprotective effect of Chunghyul-dan(Qingxuedan) against 6-0HDA-induced toxicity in the primary culture of rat mesencephalic doperminergic neurons. Results : Chunghyul-dan(Qingxuedan) showed concentration-dependent scavenging activities in DPPH radical and ABTS cation scavenging assays and it was not cytotoxic to PC12 cells. In postand co-treatment, Chunghyul-dan(Qingxuedan) protected PC12 cells from the 6-OHDA induced toxicity at 50 and 100 ${\mu}$g/mL significantly. And Chunghyu!-dan(Qingxuedan) decreased the 6-OHDA induced ROS production at a dose dependent manner, while increaing the 6-OHDA induced GSH reduction at 50 and 100 ${\mu}$g/mL significantly. Finally, Chunghyul-dan(Qingxuedan) showed signicant protection of rat mescencephalic dopaminergic neurons from 6-OHDA at 1 ${\mu}$g/mL. Conclusions : These results demonstrate that Chunghyul-dan(Qingxuedan) has the antioxidant and neuroprotective effect against 6-0HDA induced cytotoxicity through decreasing ROS production and increasing GSH reduction.

• 대한한의학회지
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• 제30권4호
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• pp.79-92
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• 2009

Objectives: The aim of the present study was to explore the neuroprotective effect and the possible mechanism of the PD-1 extracts on 1-methyl-4-phenyl-1,2,3,6-tetrahydrophridine (MPTP)-lesioned C57BL/6 mouse model of Parkinson's disease (PD). Methods: The mice were supplemented (or not) with 50 or 100 mg/kg/day of PD-1 for 2 weeks, after which MPTP was injected intraperitoneally. We observed that daily administration of PD-1 prevented MPTP-induced depletion of striatal DA, and maintained striatal and nigral tyrosine hydroxylase (TH) protein levels. Results: Our results demonstrated that mice treated with PD-1 prior to MPTP administration showed more abundant TH-immunopositive (TH-ir) fibers and neurons than mice given only MPTP, indicating that PD-1 protects dopaminergic striatal fibers and nigral neurons from MPTP insults. Possible neuroprotective effect of PD-1 was further studied by the detection of antiapoptotic protein (bcl-2) and proapoptotic protein (Bax). In this assay, MPTP elevated the Bax protein and decreased the bcl-2 protein, while these expressions were prevented by PD-1 pre-treatment. Conclusions: The present results suggest that PD-1 is able to protect dopaminergic neurons from MPTP-induced neuronal injury with anti-apoptotic activity being one of the possible mechanisms.

• 생약학회지
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• 제49권3호
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• pp.231-239
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• 2018

Parkinson's disease (PD), one of common neurodegenerative diseases, is caused by the death of dopaminergic neurons in the substantia nigra pars compacta. The loss of dopaminergic neurons in PD is associated with oxidative stress and mitochondrial dysfunction. Hyperoside (quercetin 3-O-${\beta}$-D-galactopyranoside) was reported to have protective properties against oxidative stress by reducing intracellular reactive oxygen species (ROS) and increasing antioxidant enzyme activity. In this study, we examined the neuroprotective effect of hyperoside against 1-methyl-4-phenyl pyridinium ($MPP^+$)-induced cell model of PD and the underlying molecular mechanisms. Hyperoside significantly decreased $MPP^+$-induced cell death, accompanied by a reduction in poly ADP-ribose polymerase (PARP) cleavage. Furthermore, it attenuated $MPP^+$-induced intracellular ROS and disruption of mitochondrial membrane potential (MMP), with the reduction of Bax/Bcl-2 ratio. Moreover, hyperoside significantly increased the phosphorylation of Akt, but it has no effects on $GSK3{\beta}$ and MAPKs. Pharmacological inhibitor of PI3K/Akt abolished the cytoprotective effects of hyperoside against $MPP^+$. Taken together, these results demonstrate that hyperoside significantly attenuates $MPP^+$-induced neurotoxicity through PI3K/Akt signaling pathways in SH-SY5Y cells. Our findings suggest that hyperoside might be one of the potential candidates for the treatment of PD.

• Biomolecules & Therapeutics
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• 제20권1호
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• pp.1-18
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• 2012

Schizophrenia is a devastating psychiatric illness that afflicts 1% of the population worldwide, resulting in substantial impact to patients, their families, and health care delivery systems. For many years, schizophrenia has been felt to be associated with dysregulated dopaminergic neurotransmission as a key feature of the pathophysiology of the illness. Although numerous studies point to dopaminergic abnormalities in schizophrenia, dopamine dysfunction cannot completely account for all of the symptoms seen in schizophrenia, and dopamine-based treatments are often inadequate and can be associated with serious side effects. More recently, converging lines of evidence have suggested that there are abnormalities of glutamate transmission in schizophrenia. Glutamatergic neurotransmission involves numerous molecules that facilitate glutamate release, receptor activation, glutamate reuptake, and other synaptic activities. Evidence for glutamatergic abnormalities in schizophrenia primarily has implicated the NMDA and AMPA subtypes of the glutamate receptor. The expression of these receptors and other molecules associated with glutamate neurotransmission has been systematically studied in the brain in schizophrenia. These studies have generally revealed region- and molecule-specifi c changes in glutamate receptor transcript and protein expression in this illness. Given that glutamatergic neurotransmission has been implicated in the pathophysiology of schizophrenia, recent drug development efforts have targeted the glutamate system. Much effort to date has focused on modulation of the NMDA receptor, although more recently other glutamate receptors and transporters have been the targets of drug development. These efforts have been promising thus far, and ongoing efforts to develop additional drugs that modulate glutamatergic neurotransmission are underway that may hold the potential for novel classes of more effective treatments for this serious psychiatric illness.

• Molecules and Cells
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• 제26권3호
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• pp.243-249
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• 2008

Corticotropin releasing factor (CRF) mediates various responses to stress through CRF receptors 1 and 2. CRF receptor 2 has two forms, $2{\alpha}$ and $2{\beta}$ each of which appears to have distinct roles. Here we used dopaminergic neuron-derived MN9D cells to investigate the function of CRF receptor 2 in dopamine neurons. We found that n-butyrate, a histone deacetylase inhibitor, induced MN9D cell differentiation and increased gene expression of all CRF receptors. CRF receptor $2{\beta}$ was minimally expressed in MN9D cells; however, its expression dramatically increased during differentiation. CRF receptor $2{\beta}$ expression levels appeared to correlate with neurite outgrowth, suggesting CRF receptor $2{\beta}$ involvement in neuronal differentiation. To validate this statement, we made a CRF receptor $2{\beta}$-overexpressing $MN9D/CRFR2{\beta}$ stable cell line. This cell line showed robust neurite outgrowth and GAP43 overexpression, together with MEK and ERK activation, suggesting MN9D cell neuronal differentiation. From these results, we conclude that CRF receptor $2{\beta}$ plays an important role in MN9D cell differentiation by activating the MEK/ERK signaling pathway.

• 약학회지
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• 제55권6호
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• pp.510-515
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• 2011

Isoquinoline compounds including berberine enhance L-DOPA-induced cytotoxicity in PC12 cells. In this study, the effects of berberine on L-DOPA therapy in unilateral 6-hydroxydopamine (6-OHDA)-induced rat models of parkinsonism were investigated. Rats were prepared for the models of Parkinson's disease by 6-OHDA-lesioning for 14 days and then treated with L-DOPA (10 mg/kg) with or without berberine (5 and 30 mg/kg, i.p.) for 21 days. Treatment with berberine (5 and 30 mg/kg, i.p.) showed a dopaminergic cell loss in substantia nigra of 6-OHDA-lesioned rats treated with L-DOPA: 30 mg/kg berberine was more intensive neurotoxic. The levels of dopamine were also decreased by berberine (5 and 30 mg/ kg) in striatum-substantia nigra of 6-OHDA-lesioned rats treated with L-DOPA. These results suggest that berberine aggravates cell death of dopaminergic neurons in L-DOPA-treated 6-OHDA-lesioned rat models of Parkinson's disease. Therefore, the long-term L-DOPA therapeutic patients with isoquinoline compounds including berberine may need to be checked for the adverse symptoms.

• 고려인삼학회:학술대회논문집
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• 고려인삼학회 1998년도 Advances in Ginseng Research - Proceedings of the 7th International Symposium on Ginseng -
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• pp.168-173
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• 1998

A single administration of cocaine (CO), morphine (MOR) and methamphetamine (MA) showed hyperactivity in mice. Ginseng total saponin (GTS), ginsenosides Rbl and Rgl inhibited the hyperactivity induced by the drugs. The repeated administration of CO, MOR and MA showed the development of psychological dependence showing a.: the development of conditioned place preference (CPP) in mice and the development of dopamine (DA) receptor supersensitivity showing as sensitization of the drugs. GTS and Rgl inhibited the development of not only psychological dependence but also of DA receptor supersensitivity induced by CO and MA Rbl prevented also the development of psychological dependence and DA receptor supersensitivity induced by CO and MA but not by MOR. These results suggest that the development psychological dependence induced by the drugs is closely related with the development of DA receptor supersensitivity since both phenomena were inhibited by them. Apomorphine induced climbing behavior was also inhibited by G75 but not by both of Rbl and Rgl, indicating that GTS modulate dopaminergic action at both of pre and postsynaptic sites, but both of Rbl and Rgl , only at the presynaptic site. These results suggest that active components acting at the postsynaptic site exist in GTS. In this study, it was found that GTS, ginsenosides Rbl and Rgl inhibited tyrosine hydroxylase (TH) and these components exerted inhibitory effects on both Cal' currents and $\Delta$ Cm in rat adrenal chromaffin cells. These results suggest that G75 and ginsenosides regulate catecholamine synthesis and secretion. Meanwhile, it has been demonstrated that Rbl, at high doses has more powerful inhibition of cartecholamine secretion at the presynaptic site than Rbl. Therefore, it was presumed that inhibition of morphine induced psychological dependence by Rgl, but not by Rbl results from differences in the extent of this inhibitory action on dopaminergic synthesis and secretion.

• Journal of Ginseng Research
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• 제17권3호
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• pp.187-195
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• 1993

We have examined the functional role of central dopaminergic processes on the behavioral pharmacological effects induced by psychotropics and red ginseng saponins of normal rats and compared with that of brain damaged rats. Desipramine and clomipramine produced, a significant depression of the locomotor activity in normal rats, but in brain damaged rats, they did not have any effect throughout the experimental period of 4 hours. Total saponin (50~200 mg/kg), PT (25~50 mg/kg), PD (25~50 mg/kg), $Rg_1$(12.5~25 mg/kg), $Rb_1$ (12.5~50 mg/kg) did not change, and high concentrations of PT (100 mg/kg), PD (100 mg/kg) and $Rg_1$ (50 mg/kg) showed a significant decrease in the locomotor activity of one hour after administration but total saponin (100 mg/kg), PD (25~50 mg/kg), Rgl (12.5 mg/kg), $Rb_1$ (12.5 mg/kg) markedly increased the locomotor activity of four hour after administration in normal rats. On the other hand, total saponin (50 mg/kg), PT (100 mg/kg) and PD (100 mg/kg) Produced a prominent stimulation of the locomotor activity in brain damaged rats. These results suggest that the inhibition of the locomotor activity induced by antidepressants was not affected by the sensitivity of cerebral DA system, whereas red ginseng saponin showed antifatigue effect and also the stimulation of the locomotor activity induced by red ginseng saponin was mediated by the inhibition of cerebral DA system. These psychotropic action of red ginseng saponins could be responsible for the beneficial effects on conditions of fatigue and decreased alertness.

• Journal of Ginseng Research
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• 제42권4호
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• pp.429-435
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• 2018

Background: Recent studies have shown that Korean Red Ginseng (KRG) successfully protects against dopaminergic neuronal death in the nigrostriatal pathway of a Parkinson's disease (PD) mouse model induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) administration; however, the mechanism has yet to be identified. Therefore, in this study we used two-dimensional electrophoresis to investigate the effects of KRG on the changes in protein expression in the substantia nigra (SN) of MPTP-treated mice. Methods: Male C57BL/6 mice (9 wk old) were intraperitoneally administered MPTP (20 mg/kg) four times at 2-h intervals, after which KRG (100 mg/kg) was orally administered once a day for 5 d. Two hours after the fifth KRG administration, a pole test was conducted to evaluate motor function, after which the brains were immediately collected. Survival of dopaminergic neurons was measured by immunohistochemistry, and protein expression was measured by two-dimensional electrophoresis and Western blotting. Results: KRG alleviated MPTP-induced behavioral dysfunction and neuronal toxicity in the SN. Additionally, the expression of eight proteins related to neuronal formation and energy metabolism for survival were shown to have changed significantly in response to MPTP treatment or KRG administration. KRG alleviated the downregulated protein expression following MPTP administration, indicating that it may enhance neuronal development and survival in the SN of MPTP-treated mice. Conclusion: These findings indicate that KRG may have therapeutic potential for the treatment of patients with PD.