• The Korean Journal of Physiology and Pharmacology
• /
• v.17 no.5
• /
• pp.393-403
• /
• 2013

Baicalein (BA), a plant-derived active flavonoid present in the root of Scutellaria baicalensis, has been widely used for the treatment of stress-related neuropsychiatric disorders including depression. Previous studies have demonstrated that repeated restraint stress disrupts the activity of the hypothalamic-pituitary-adrenal (HPA) axis, resulting in depression. The behavioral and neurochemical basis of the BA effect on depression remain unclear. The present study used the forced swimming test (FST) and changes in brain neurotransmitter levels to confirm the impact of BA on repeated restraint stress-induced behavioral and neurochemical changes in rats. Male rats received 10, 20, or 40 mg/kg BA (i.p.) 30 min prior to daily exposure to repeated restraint stress (2 h/day) for 14 days. Activation of the HPA axis in response to repeated restraint stress was confirmed by measuring serum corticosterone levels and the expression of corticotrophin-releasing factor in the hypothalamus. Daily BA administration significantly decreased the duration of immobility in the FST, increased sucrose consumption, and restored the stress-related decreases in dopamine concentrations in the hippocampus to near normal levels. BA significantly inhibited the stress-induced decrease in neuronal tyrosine hydroxylase immunoreactivity in the ventral tegmental area and the expression of brain-derived neurotrophic factor (BDNF) mRNA in the hippocampus. Taken together, these findings indicate that administration of BA prior to the repeated restraint stress significantly improves helpless behaviors and depressive symptoms, possibly by preventing the decrease in dopamine and BDNF expression. Thus, BA may be a useful agent for the treatment or alleviation of the complex symptoms associated with depression.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.19 no.4
• /
• pp.982-992
• /
• 2005

Acupuncture as a therapeutic intervention is widely used for the treatment of many functional disorders such as substance abuse and mental dysfunction. Clinical trials are currently underway to determine the effectiveness of acupuncture in the treatment of drug addiction. Yet, there are still many unanswered questions about the basic mechanism of acupuncture. Studies have shown that both the psychomotor stimulant effects and rewarding properties of addictive drugs, including morphine, are sensitized by repeated drug administration and raised the possibility that both of these effects may De linked to the same or closely overlapping the mesolimbic dopamine systems. Neiguan (PC6) point on the pericardium channel which is associated with the brain and its mental function, has been used to treat mental, psychosomatic disorders and gastroenterological disorders. The present study was designed to investigate the effect of acupuncture on repeated morphine-induced changes in extracellular dopamine levels using in vivo microdialysis and to measure the effect of acupuncture on repeated morphine-induced behavioral changes. Male Sprague-Dawley rats were treated twice a day for three days with increasing doses of morphine (10, 20 and 40 mg/kg, s.c.) or with saline. After 15 days of withdrawal, rats were challenged with morphine hydrochloride (5 mg/kg, s.c.). Acupuncture was applied at bilateral Neiguan (PC6) points for 1min after the morphine challenge. Results showed that acupuncture at the specific acupoint PC6, but not at control points (tail and HE8) significantly decreased both dopamine release, behavior induced by a systemic morphine challenge or a single s.c. morphine injection in the morphine-repeated animals. These results suggest that reduction in sensitization may be one mechanism whereby acupuncture alleviates morphine craving in addicts. Moreover, in a more general sense these results suggest that acupuncture can be used as a therapeutic intervention for correcting reversible malfunction of the body by direction of brain pathway and thus acupuncture can contribute to the biochemical balance in the central nervous system by regulating neurotransmitters.

• The Journal of Internal Korean Medicine
• /
• v.25 no.4
• /
• pp.52-64
• /
• 2004

Objectives : This study was done to investigate the effect of Gamigehyuldeung-tang on hypertension. Methods : After administering Gamigehyuldeung-tang extract to SHR(Spontaneous Hypertensive Rats) for 5 weeks, changes in blood pressure, pulse rate, aldosterone and catecholamine levels in plasma were examined, and immunohistochemical changes and scanning electron microscopic changes were observed. Results : The following results were obtained; blood presure decreased significantly as well as levels of aldosterone, dopamine and epinephrine in SHR. But levels of norepinephrine were unaffected. No capillary vessel dilation was observed. A decrease in cell damage was seen in microscope investigation. Conclusions : These results support a role for Gamigehyuldeung-tang might be usefully applied in treatment of hypertension.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.20 no.3
• /
• pp.663-669
• /
• 2006

This study was done to investigate the effect of Ganyangsanghang-bang(GYSHB) on hypertension. After administering GYSHB extract to SHR for 5 weeks, changes in blood pressure, pulse rate, aldosterone and catecholamine levels in plasma were examined, and immunohistochemical changes were observed, and liver function test was done. The following results were obtained; blood presure decreased significantly as well as levels of aldosterone and norepinephrine in SHR. But levels of dopamine were unaffected. No capillary vessel dilation in adrenal cortex was observed. Safety against hepatic toxicity was showed. These results support a role for GYSHB might be usefully applied in treatment of hypertension.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.20 no.1
• /
• pp.131-137
• /
• 2006

This study was done to investigate the effect of Gamisamool-tang(GMSMT) on hypertension. After administering GMSMT extract to SHR for 5 weeks, changes in blood pressure, pulse rate, aldosterone and catecholamine levels in plasma were examined, and immunohistochemical changes were observed, and liver function test was done. The following results were obtained; blood presure decreased significantly as well as levels of aldosterone, norepinephrine and epinephrine in SHR, But levels of dopamine were unaffected. No capillary vessel dilation in adrenal cortex was observed. Safety against hepatic toxicity was showed. These results support a role for GMSMT might be usefully applied in treatment of hypertension.

• The Korean Journal of Pharmacology
• /
• v.28 no.1
• /
• pp.19-25
• /
• 1992

The effect of the nonbenzodiazepine anxiolytic, buspirone $(Buspar^R)$, a serotonin $(5-HT)_{1A}$ partial agonist, which also has dopamine $(DA)_2$ receptor antagonist properties, on prolactin and cortisol secretion was examined in eight normal male volunteers. The oral administration of buspirone (30 mg) significantly increased plasma prolactin concentrations but did not significantly increase plasma cortisol concentrations in this study. The oral administration of pindolol (30 mg), a beta adrenoceptor antagonist which is also a $5-HT_{1A}$ receptor antagonist, had no significant effect on basal prolactin or cortisol levels. Moreover, pretreatment with pindolol did not significantly inhibit the buspirone-induced increase in prolactin secretion. These preliminary data are suggestive that buspirone-induced prolactin secretion is not mediated via $5-HT_{1A}$ receptor activation.

• The Korean Journal of Physiology and Pharmacology
• /
• v.22 no.2
• /
• pp.183-192
• /
• 2018

Post-traumatic stress disorder (PTSD) is a trauma-induced psychiatric disorder characterized by impaired fear extermination, hyperarousal, anxiety, depression, and amnesic symptoms that may involve the release of monoamines in the fear circuit. The present study measured several anxiety-related behavioral responses to examine the effects of berberine (BER) on symptoms of anxiety in rats after single prolonged stress (SPS) exposure, and to determine if BER reversed the dopamine (DA) dysfunction. Rats received BER (10, 20, or 30 mg/kg, intraperitoneally, once daily) for 14 days after SPS exposure. BER administration significantly increased the time spent in the open arms and reduced grooming behavior during the elevated plus maze test, and increased the time spent in the central zone and the number of central zone crossings in the open field test. BER restored neurochemical abnormalities and the SPS-induced decrease in DA tissue levels in the hippocampus and striatum. The increased DA concentration during BER treatment may partly be attributed to mRNA expression of tyrosine hydroxylase and the DA transporter in the hippocampus, while BER exerted no significant effects on vesicular monoamine transporter mRNA expression in the hippocampus of rats with PTSD. These results suggest that BER had anxiolytic-like effects on behavioral and biochemical measures associated with anxiety. These findings support a role for reduced anxiety altered DAergic transmission and reduced anxiety in rats with PTSD. Thus, BER may be a useful agent to treat or alleviate psychiatric disorders like those observed in patients with PTSD.

• YAKHAK HOEJI
• /
• v.49 no.4
• /
• pp.355-364
• /
• 2005

A neurotoxin, 6-hydroxydopamine (6-OHDA) has long been used to form a Parkinson's disease (PD) model by inducing the lesion in catecholaminergic pathways, particularly the nigrostriatal dopamine (DA) pathway. Whereas l-deprenyl, a selective inhibitor of monoamine oxidase (MAO) type B, is now widely used in the treatment of PD, the precise action mechanism of the drug remains elusive. In this study, we investigated whether l-deprenyl shows protective effect against the DA depletion induced by 6-OHDA in rat brain, and against 6-OHDA-induced neurotoxicity and oxidative stress in catecholaminergic neuroblastoma SH-SY5Y cells that are known to lack MAO-B activity. Pretreatment of l-deprenyl significantly enhanced the striatal DA, 3,4-dihydroxyphenylacetic acid, homovanilic acid, and 3-methoxytyramine levels compared to the untreated 6-OHDA-lesioned rat, indicating that l-deprenyl pretreatment prevents 6-OHDA-induced depletion of not only striatal dopamine but also its metabolites. Treatment of 6-OHDA for 24hrs decreased the cell viability and increase the generation of ROS in dose-dependent manners. We further investigated whether caspase activity is involved in the action of l-deprenyl. Treatment of l-deprenyl $(0.1\~100{\mu}M)$ did not produce any changes in 6-OHDA-induced cleavage of poly (ADP-ridose) polymerase in SH-SY5Y cells. Our results suggest that the neuroprotective effect of l-deprenyl against 6-OHDA is due to its increased scavenger activity, but independent of inhibition of MAO-B or caspase-3 activation.

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

• Journal of Aquaculture
• /
• v.9 no.1
• /
• pp.3-10
• /
• 1996

Ovulation of maturing female yellow puffer, Takifugu obscrus, was induced by using single injection of human chorionic gonadotropin (HCG) or gonadotropin releasing hormone-analogue (GnRH-A) $des-Gly^{10}[D-Ala^6]$ GnRH-ethylamide plus pimozide. The response was evaluated using the fertilization and embryo-formation rate after insemination and the gonadotropin (GTH) level in blood plasma using radioimmunoassay. In the fertilization and embryo-formation, maximal effects were recorded by using 1,000 IU/kg HCG or $10\;{mu}g/kg$ GnRH-A plus 5 mg/kr pimozide. Pimozide (1, 5 mg/kg) or GnRH-A treatment alone was not effective in elevation of GTH level, however combinations of these treatments were particularly effective. Injection of dopamine blocked the rapid elevation of plasma GTH levels of blood. These data suggest that yellow puffer secrete GnRH and gonadotropin-releasing-inhibiting factor during the spawning or the other period.