Yoo-Sun Moon

Protection against β-amyloid peptide-induced memory impairment with long-term administration of extract of Angelica gigas or decursinol in mice

We investigated the effect of long-term oral administration of ethanolic extract of Angelica gigas Nakai (Umbelliferae) (EAG) or decursinol, a coumarin isolated from A. gigas, on beta-amyloid peptide 1-42 (Abeta(1-42))-induced memory impairment in mice. Mice were allowed free access to drinking water (control) or water containing different concentrations of EAG. After 4 weeks, Abeta(1-42) (410 pmol) was administered via intracerebroventricular injection. Pretreatment of mice with EAG (0.1%) for 4 weeks significantly blocked the Abeta(1-42)-induced impairment in passive avoidance performance. Next, mice were fed with chow mixed with various doses of decursinol for 4 weeks before intracerebroventricular injection of Abeta(1-42) (410 pmol). Pretreatment of mice with decursinol (0.001%, 0.002%, and 0.004%) for 4 weeks significantly attenuated the Abeta(1-42)-induced impairment in passive avoidance performance. Decursinol (0.004%) also significantly blunted the Abeta(1-42)-induced decrease in alternation behavior (spatial working memory) in the Y-maze test without change in general locomotor activity. These findings suggest that EAG or decursinol may have preventive effect against memory impairment related with Abeta of Alzheimers disease.

Effects of ginseng saponin administered intraperitoneally on the hypothalamo-pituitary-adrenal axis in mice.

Intraperitoneal injection of ginseng total saponin (GTS; 5 and 20 mg/kg) raised plasma corticosterone levels in mice. However, interestingly, pretreatment of animals with the same doses of GTS (5 and 20 mg/kg) significantly attenuated the immobilization stress-induced increase in plasma corticosterone levels. Of the ginsenosides Rb(1), Rb(2), Rc, Rd, Re, Rf, Rg(1), 20(S)-Rg(3), and 20(R)-Rg(3) injected intraperitoneally at doses of 0.1-2 mg/kg, Rc (2 mg/kg) significantly inhibited the immobilization stress-induced increase in plasma corticosterone levels. GTS and Rc administered intraperitoneally did not affect the immobilization stress-induced elevation of plasma adrenocorticotropic hormone (ACTH) level. Pretreatment with GTS and Rc significantly attenuated the increase in plasma corticosterone levels induced by intraperitoneal injection of ACTH (30 microg/kg). These results suggest that GTS and Rc inhibit the immobilization stress-induced increase in plasma corticosterone levels by blocking ACTH action in the adrenal gland. Ginseng may be proposed to be useful for treatment of stress related disorders.

Effect of Zen Meditation on serum nitric oxide activity and lipid peroxidation.

This study was designed to investigate the effect of Zen Meditation on serum nitric oxide activity (NO) and oxidative stress (lipid peroxidation). The experimental group included 20 subjects who had practiced the Zen Meditation program in Meditation Center located in Seoul, South Korea. The control group included 20 subjects who did not practice any formal stress management technique and were age and sex matched with experimental group. To provide an assessment of nitric oxide production, the serum level of nitrate/nitrite was determined using the Griess reagent. Malondialdehyde (MDA) concentration was measured as a convenient index of lipid peroxidation by thiobarbituric acid (TBA) method. Meditation group showed a significant higher level of serum nitrate+nitrite concentration and a significant reduced level of serum malondialdehyde (MDA) than control group. A comprehensive randomized controlled trial should be performed to prove the causal relationship between meditation and level of nitric oxide or oxidative stress in reducing cardiovascular risk factors.

Correlates of quality of life after stroke

The relationship between lesion location and quality of life (QOL) in stroke patients has not yet been clearly revealed. The present study was undertaken to investigate the clinical and anatomical correlates which can predict future QOL in stroke patients. The study subjects consisted of 69 consecutive patients with ischemic stroke who were followed up 2 months after the stroke event at the stroke unit. Quality of life was evaluated during the 2-month follow up period after the stroke. Baseline information or data including clinical and anatomical correlates (Beck Depression Inventory, Beck Anxiety Inventory, Barthels Index, MRI data) at the time of the stroke event were collected by performing a review of each patients chart and research data files. Severe subcortical gray matter lesion and depressive symptoms in the acute phase of stroke were of importance in predicting low QOL 2 months after stroke.

The inhibitory effect of ginseng saponins on the stress-induced plasma interleukin-6 level in mice.

The effect of ginseng saponins on plasma interleukin-6 (IL-6) in non-stressed and immobilization-stressed mice were investigated. Ginseng total saponins, ginsenosides Rb2, Rg1 and Rd administered intraperitoneally attenuated the immobilization stress-induced increase in plasma IL-6 level. But, intracerebroventricular injection of each ginsenoside did not affect plasma IL-6 level induced by immobilization stress. Ginsenosides Rb2, Rd and Rg1 significantly decreased norepinephrine and/or epinephrine-induced increase of IL-6 level in macrophage cell line (RAW 264.7). Thus, it can be suggested that the inhibitory action of ginseng saponins against the immobilization stress-induced increase of plasma IL-6 level would be in periphery; at least in part, mediated by blocking norepinephrine- and/or epinephrine-induced increase of IL-6 level in macrophage rather than in the brain. Ginseng saponins might be proposed as a possible candidate in the research or therapeutic modulation of stress-related disorders.

The Effect of Depression on Serum VEGF Level in Alzheimer’s Disease

Objective. Growing evidence suggests that angiogenesis might represent a new pathogenic mechanism involved in the progression of Alzheimers disease (AD). Among angiogenic cytokines, vascular endothelial growth factor (VEGF) levels in AD patients have been evaluated, but the results are controversial among studies. We investigated serum levels of VEGF in AD patients with depression, AD patients without depression, and the controls, respectively. The aim of this study is to elucidate the relationship between VEGF, depression, and cognitive impairment in AD. Methods. The CDR (Clinical Dementia Rating), MMSE-KC (the Mini-Mental Status Examination-Korean version), and SGDS-K (the Korean version of the Geriatric Depression Scale-Short Form) were measured in the subjects. Serum VEGF levels were measured in 24 AD patients with depression, 25 AD patients without depression, and 26 controls, using an enzyme-linked immunosorbent assay kit. Results. Serum VEGF levels in AD patients with depression were significantly higher than AD patients without depression or the control. A correlation was observed between VEGF and scores on SGDS-K, but no correlation was detected between VEGF and MMSE-KC scores. Conclusion. Serum VEGF levels in AD patients with depression were higher than those without depression. Depression might be associated with changes in serum levels of VEGF in AD patients.

Route-dependent effects of the non-NMDA receptor antagonist CNQX on plasma corticosterone levels in mice

A non-N-methyl-D-aspartate (non-NMDA) receptor antagonist, 6-cyano-7-nitro-quinoxaline-2,3-dione (CNQX), administered intracerebroventricularly (0.1-0.5 microg), significantly inhibited the immobilization stress-induced plasma corticosterone levels in a dose-dependent manner. However, CNQX administered intraperitoneally (1-10 mg/kg) showed a dose-dependent increase of basal plasma corticosterone levels in nonstressed mice and an additive increase of plasma corticosterone levels at the dose of 10 mg/kg in 1 h immobilization-stressed mice. The results suggest that the central and peripheral non-NMDA receptors may be differently involved in the regulation of plasma corticosterone levels in non- and immobilization-stressed mice.

Central or peripheral norepinephrine depletion enhances MK-801-induced plasma corticosterone level in mice.

To investigate the involvement of central or peripheral catecholaminergic systems in the MK-801-induced increase in plasma corticosterone and interleukin-6 levels, we pretreated mice either intracerebroventricularly (i.c.v.) or intraperitoneally (i.p.) with 6-hydroxydopamine (6-OHDA) which depletes catecholamines. Pretreatment of animals with 6-OHDA (50 microg i.c.v. or 100 mg/kg i.p.) significantly enhanced the MK-801 (1 microg i.c.v.)-induced increase in plasma corticosterone level. On the other hand, pretreatment of mice with 6-OHDA (50 microg i.c.v. or 100 mg/kg i.p.) did not affect the MK-801 (1 microg i.c.v.)-induced increase in plasma IL-6 level. These results suggest that central and peripheral catecholaminergic systems are involved in the suppressive regulation of MK-801-induced plasma corticosterone level.