Increased non-rapid eye movement sleep by cocaine withdrawal: possible involvement of A2A receptors

This study attempted to clarify whether cocaine withdrawal altered sleep architecture and the role of adenosine receptors in this process. Cocaine (20 mg/kg) was administered subcutaneously once per day for 7 days to rat implanted with sleep/wake recording electrode. Polygraphic signs of undisturbed sleep/wake activities were recorded for 24 h before cocaine administration (basal recording as control); withdrawal-day 1 (after 1 day of repeated cocaine administration), withdrawal-day 8 (after 8 days of repeated cocaine administration), and withdrawal-day 14 (after 14 days of repeated cocaine administration), respectively. On cocaine withdrawal-day 1, wakefulness was significantly increased, total sleep was decreased, non-rapid eye movement sleep was markedly reduced, and rapid eye movement sleep was enhanced. Sleep/wake cycles were also increased on cocaine withdrawal day 1. However, non-rapid eye movement sleep was increased on withdrawal-day 8 and 14, whereas rapid eye movement sleep was decreased and no significant changes were observed in the total sleep and sleep/wake cycles during these periods. Adenosine A(2A) receptors expression was increased on withdrawal-day 8 and 14, whereas A(1) receptors levels were reduced after 14 days of withdrawal and the A(2B) receptors remained unchanged. Our findings suggest that alterations of sleep and sleep architecture during cocaine subacute and subchronic withdrawals after repeated cocaine administration may be partially involved in A(2A) receptors over-expression in the rat hypothalamus.

Magnolol enhances pentobarbital-induced sleeping behaviors: possible involvement of GABAergic systems

This study was performed to investigate whether magnolol enhances pentobarbital-induced sleeping behaviors through the GABAergic systems. Magnolol prolonged the sleeping time induced by pentobarbital. In addition, magnolol increased chloride influx in primary cultured cerebellar granule cells. The expression of the GABA(A) receptor alpha-subunit was increased selectively by magnolol, but magnolol had no effect on the abundance of beta- or gamma-subunits. The expression of glutamic acid decarboxylase (GAD) was not influenced by magnolol. It is suggested that magnolol may enhance pentobarbital-induced sleeping behaviors through the activation of GABAergic systems.

4-O-Methylhonokiol attenuates memory impairment in presenilin 2 mutant mice through reduction of oxidative damage and inactivation of astrocytes and the ERK pathway

Presenilin 2 (PS2) mutation increases Aβ generation and neuronal cell death in the brains of Alzheimer disease (AD) patients. In a previous study, we showed that increased oxidative damage and activation of extracellular signal-regulated kinase (ERK) were associated with Aβ generation and neuronal cell death in neuronal cells expressing mutant PS2. In this study, we show that oral treatment with 4-O-methylhonokiol, a novel compound isolated from Magnolia officinalis, for 3 months (1.0mg/kg) prevented PS2 mutation-induced memory impairment and neuronal cell death accompanied by a reduction in Aβ(1-42) accumulation. We also found that 4-O-methylhonokiol inhibited PS2 mutation-induced activation of ERK and β-secretase, and oxidative protein and lipid damage, but recovered glutathione levels in the cortex and hippocampus of PS2 mutant mice. Additionally, 4-O-methylhonokiol prevented PS2 mutation-induced activation of astrocytes as well as production of TNF-α, IL-1β, reactive oxygen species (ROS), and nitric oxide (NO) in neurons. Generation of TNF-α, IL-1β, ROS, and NO and ERK activation in cultured astrocytes treated with lipopolysaccharide (1μg/ml) were also prevented by 4-O-methylhonokiol in a dose-dependent manner. These results suggest that the improving effects of 4-O-methylhonokiol on memory function may be associated with a suppression of the activation of ERK and astrocytes as well as a reduction in oxidative damage. Thus, 4-O-methylhonokiol may be useful in the prevention and treatment of AD.

4-O-methylhonokiol attenuated β-amyloid-induced memory impairment through reduction of oxidative damages via inactivation of p38 MAP kinase

Oxidative stress induced neuronal cell death by accumulation of β-amyloid (Aβ) is a critical pathological mechanism of Alzheimer's disease (AD). Intracerebroventrical infusion of Aβ(1-42) (300 pmol/day per mouse) for 14 days induced neuronal cell death and memory impairment, but pre-treatment of 4-O-methylhonokiol (4-O-MH), a novel compound extracted from Magnolia officinalis for 3 weeks (0.2, 0.5 and 1.0 mg/kg) prior to the infusion of Aβ(1-42) and during the infusion dose dependently improved Aβ(1-42)-induced memory impairment and prevented neuronal cell death. Additionally, 4-O-MH reduced Aβ(1-42) infusion-induced oxidative damages of protein and lipid but reduced glutathione levels in the cortex and hippocampus. Aβ(1-42) infusion-induced activation of astrocytes and p38 mitogenic activated protein (MAP) kinase was also prevented by 4-O-MH in mice brains. In further study using culture cortical neurons, p38 MAP kinase inhibitor abolished the inhibitory effect of 4-O-MH (10 μM) on the Aβ(1-42) (5 μM)-induced reactive oxidative species generation and neuronal cell death. These results suggest that 4-O-MH might prevent the development and progression of AD through the reduction of oxidative stress and neuronal cell death via inactivation of p38 MAP kinase pathway.

(-)-Epigallocatechin-3-O-gallate (EGCG) reverses caffeine-induced anxiogenic-like effects

This study was designed to determine whether (-)-epigallocatethin-3-O-gallate (EGCG) could reverse caffeine-induced anxiogenic-like effects in animals. In mice, EGCG antagonized the caffeine-induced reduction in both the open arm entry number and time-spent in open arm on elevated plus-maze. In addition, EGCG also antagonized the caffeine-induced reduction in both the central zone distance and central zone time-spent on an open field apparatus, respectively. Electroencephalogram (EEG) was recorded from the rat anterior cerebral cortex. Caffeine increased the power density-ratios of fast (FW: 8.00-20.00 Hz) and slow (SW: 0.75-8.00 Hz) frequency spectrum bands in these EEG recordings. However, EGCG reduced the caffeine-induced increase of FW/SW ratios. Thus, EGCG reverses caffeine-induced anxiogenic-like effects. We also provide additional evidence that the EEG FW/SW (or SW/FW) ratios can be a useful tool for the prediction of anxiogenic and/or anxiolytic effects in an animal model.

Obovatol enhances docetaxel-induced prostate and colon cancer cell death through inactivation of nuclear transcription factor-kappaB

Nuclear transcription factor-kappaB (NF-kappaB) is constitutively activated in prostate and colon cancers and is related with the resistance of cancer cells against chemotherapeutics. Previously, we found that obovatol, an active compound isolated from Magnolia obovata, inhibited cancer cell growth through inhibition of NF-kappaB activity. We investigated here whether obovatol could sensitize cancer cells against docetaxel through inhibition of NF-kappaB activity in prostate cancer (LNCaP and PC-3) and colon cancer (SW620 and HCT116) cells. The combination treatment with each drug at one half the respective IC(50) dose (5 microM obovatol + 5 nM docetaxel) was more effective and significant (60%-70%) in the inhibition of cancer cell growth than single treatment by each drug (20%-40%); inhibition was exerted through a significant increase of apoptosis induction (60%-80%) by the combination treatment compared to the single treatment (10%-30%). Correlating well with the synergistic inhibition (combination indices are less than 1 in all cell types), the combination significantly inhibited NF-kappaB activities as well as expression of NF-kappaB target apoptotic cell death proteins, but decreased anti-apoptotic cell death proteins. Similar combination effects of obovatol with other chemotherapeutic agents (paclitaxel, cisplatin, and doxorubicin) on the inhibition of cell growth and NF-kappaB activity were also found. These results indicate that obovatol augments cell growth inhibition by chemotherapeutics through inactivation of NF-kappaB and suggest that obovatol may have therapeutic advantages in the combination treatment with other chemotherapeutics. [Supplementary Figure: available only at http://dx.doi.org/10.1254/jphs.09048FP].

Combination of ginsenoside Rg3 with docetaxel enhances the susceptibility of prostate cancer cells via inhibition of NF-kappaB

Ginsenoside Rg3 has been a subject of interest for use as a cancer preventive or therapeutic agent. Nuclear factor-kappa (NF-kappaB) is constitutively activated in prostate cancer, and gives cancer cells resistance to chemotherapeutic agents. To investigate whether Rg3 can suppress the activation of NF-kappaB, and thus increase susceptibility of prostate (LNCaP and PC-3, DU145) cells against chemotherapeutics, prostate cancer cell growth as well as activation of NF-kappaB was examined. We found that a combination treatment of Rg3 (50 microM) with a conventional agent docetaxel (5 nM) was more effective in the inhibition of prostate cancer cell growth and induction of apoptosis as well as G(0)/G(1) arrest accompanied with the significant inhibition of NF-kappaB activity than those by treatment of Rg3 or docetaxel alone. It was also found that NF-kappaB target gene expression of Bax, caspase-3, and caspase-9 was much more significantly enhanced, but the expression of Bcl-2, inhibitor of apoptosis protein (IAP-1) and X chromosome IAP (XIAP), and the expression of cell cycle regulatory proteins cyclin B, D1 and E, and cyclin dependent kinases 2 and 4 was also much more significantly inhibited by the combination treatment. The combination of Rg3 (50 microM) with cisplatin (10 microM) and doxorubicin (2 microM) was also more effective in the inhibition of prostate cancer cell growth and NF-kappaB activity than those by the treatment of Rg3 or chemotherapeutics alone. These results indicate that ginsenoside Rg3 inhibits NF-kappaB, and enhances the susceptibility of prostate cancer cells to docetaxel and other chemotherapeutics. Thus, ginsenoside Rg3 could be useful as an anti-cancer agent.

Comparative antihypertensive activities of losartan and HM70186 in rats with hepatic dysfunction

HM70186, a medoxomil ester of EXP3174 which is an active metabolite of angiotensin II receptor blocker losartan, was synthesized, and its antihypertensive efficacy was evaluated in rats with hepatic dysfunction. Male Wistar rats were intraperitoneally injected with 0.5 mL/kg of carbon tetrachloride to cause hepatic injury, and implanted with an osmotic minipump containing angiotensin II (0.4 mg/kg/day) to induce hypertension. After confirmation of both hepatic damage and hypertension, the rats were orally administered losartan or HM70186, and then blood pressure and heart rate were monitored for 24 h. In normal animals, angiotensin II-induced hypertension was lowered by losartan, resulting in an ED(-30 mmHg) of 9.05 mg/kg. HM70186 also immediately decreased the blood pressure in a dose-dependent manner, exhibiting an ED(-30 mmHg) of 0.89 ng/kg (10,000 times the potency observed with losartan). Moreover, HM70186 (3 ng/kg) exerted a strong antihypertensive effect even in rats with hepatic injury, while losartan (10 microg/kg) was ineffective. These results suggest that HM70186 could be a promising candidate for the treatment of hypertension accompanied by hepatic dysfunction.

Relationship between body composition and bone mineral density (BMD) in perimenopausal Korean women

OBJECTIVES

Osteoporosis is a disease that increases the fracture rates and it is the major cause of increased mortality and morbidity in the elderly people. To determine which component of body composition is most important to bone health, we analysed the relationship between elements of the body composition and bone mineral density (BMD) in Korean women.

DESIGN

Cross-sectional clinical study.

PATIENTS

Totally 1694 women (mean age 51 years) were selected from subjects who participated in a medical check-up program.

MEASUREMENTS

Body composition analysis was performed by segmental bioelectric impedance method and lean mass, fat mass and per cent body fat measured. Waist: hip ratio (WHR) was assessed as a marker for visceral fat. Lumbar spine (L-spine) BMD was measured by dual X-ray absorptiometry (DEXA). As menopausal status could not be confirmed in all subjects, we divided the subjects into two groups according to the age > 50 years and < 50 years.

RESULTS

Among the entire population, 599 subjects (35.4%) were osteopaenic and 229 subjects (13.5%) were osteoporotic. The bivariate correlation among the variables showed that weight had the highest correlation with fat mass. Mean lean mass was decreased and the WHR increased as the subjects progressed from normal to osteoporotic status; fat mass was the highest among the osteopaenic subjects. L-spine BMD showed a positive correlation with lean mass, and a negative correlation with WHR by bivariate correlation analysis. However, fat mass had a negative correlation with L-spine BMD only after adjustment for age and weight. Multiple regression analysis with L-spine BMD as the dependent variable showed that age, height, fasting insulin, lean mass and WHR were significant determinants of the L-spine BMD (R(2) = 0.170, P < 0.05).

CONCLUSION

In this Korean female population, L-spine BMD showed a consistently positive correlation with lean mass and a negative correlation with WHR. Fat mass failed to show any consistent correlation with L-spine BMD in this study population.

Inhibition of NF-kappaB by ginsenoside Rg3 enhances the susceptibility of colon cancer cells to docetaxel

Ginsenoside Rg3, the main constituent isolated from Panax ginseng, has been of interest for use as a cancer preventive or therapeutic agent. We investigated here whether Rg3 can inhibit the activity of NF-kappaB, a key transcriptional factor constitutively activated in colon cancer that confers cancer cell resistance to chemotherapeutic agents. To investigate whether RG3 can suppress activation of NF-kappaB, and thus inhibit cancer cell growth, we examined the susceptibility of colon cancer cells (SW620 and HCT116) to treatment with Rg3 (25, 50, 75, 100 microM) and RG3-induced activation of NF-kappaB. RG3 dose-dependently inhibited cancer cell growth through induction of apoptosis and decreased NF-kappaB activity. In a further study of compounds in colon cancer, we used half of the IC(50) dose, values in combined treatments of Rg3 (50 microM) with conventional agents - docetaxel (5 nM), paclitaxel (10 nM) cisplatin (10 microM) and doxorubicin (2 microM). Compared to treatment with Rg3 or chemotherapy alone, combined treatment was more effective (i.e., there were synergistic effects) in the inhibition of cancer cell growth and induction of apoptosis and these effects were accompanied by significant inhibition of NF-kappaB activity. NF-kappaB target gene expression of apoptotic cell death proteins (Bax, caspase-3, caspase-9) was significantly enhanced, but the expression of anti-apoptotic genes and cell proliferation marker genes (Bcl-2, inhibitor of apoptosis protein (IAP-1) and X chromosome IAP (XIAP), Cox-2, c-Fos, c-Jun and cyclin D1) was significantly inhibited by the combined treatment compared to Rg3 or docetaxel alone. These results indicate that ginsenoside Rg3 inhibits NF-kappaB, and enhances the susceptibility of colon cancer cells to docetaxel and other chemotherapeutics. Thus, ginsenoside Rg3 could be useful as an anti-cancer or adjuvant anti-cancer agent.

Obovatol isolated from Magnolia obovata enhances pentobarbital-induced sleeping time: Possible involvement of GABAA receptors/chloride channel activation

This study aimed to investigate the effects of obovatol isolated from Magnolia obovata on pentobarbital-induced sleeping behaviors and to determine whether these effects were mediated by GABA(A) receptors/chloride channel activation, using a western blot technique and Cl(-) sensitive fluorescence probe. GABA(A) receptors subunits expression and chloride influx were investigated in cultured cerebellar granule cells. Obovatol (0.05, 0.1, and 0.2 mg/kg) prolonged the sleeping time induced by pentobarbital (42 mg/kg). In addition, obovatol (20 and 50 microM) significantly increased Cl(-) influx in the primary cultured cerebellar granule cells. Moreover, obovatol increased the expression of GABA(A) receptor alpha-, beta-, and gamma-subunits. However, it had no effect on the abundance of the expression of glutamic acid decarboxylase (GAD), suggesting that obovatol might not activate GAD. These results suggest that obovatol potentiates pentobarbital-induced sleeping time through the GABA(A) receptors/chloride channel activation.

Methanol extract of Longanae Arillus augments pentobarbital-induced sleep behaviors through the modification of GABAergic systems

This experiment was performed to investigate whether methanol extract of Longanae Arillus (MELA) has hypnotic effects and/or enhances pentobarbital-induced sleep behaviors through the GABAergic systems. MELA prolonged sleep time and reduced sleep latency induced by pentobarbital similar to muscimol, a GABAA receptors agonist. MELA also increased sleep rate and sleep time in the combined administration with pentobarbital at the sub-hypnotic dosage and showed synergic effects with muscimol in potentiating sleep onset and enhancing sleep time induced by pentobarbital. However, MELA itself did not induce sleep at higher dose which was used in this experiment. In addition, both of MELA and pentobarbital increased chloride influx in primary cultured cerebellar granule cells. MELA increased GABAA receptors gamma-subunit expression and had no effect on the expression of alpha- and beta-subunits, and glutamic acid decarboxylase (GAD) in primary cultured cerebellar granule cells, showing different expression of subunits from pentobarbital. In conclusion, MELA itself does not induce sleep, but it augments pentobarbital-induced sleep behaviors through the modification of GABAergic systems.

The association of serum adipocyte fatty acid-binding protein with coronary artery disease in Korean adults

OBJECTIVES

Adipocyte fatty acid-binding protein (A-FABP), also known as aP2 or FABP4, is abundantly expressed in adipocytes and plays a role in glucose homeostasis. We analyzed the relationship between the coronary artery disease and serum FABP4 levels in Korean adults.

METHODS

In a total of 234 Korean adults, in whom coronary angiograms were performed, anthropometric measurements were done and fasting glucose and lipid profiles were measured. Serum FABP4 levels were measured using ELISA. The presence of metabolic syndrome was diagnosed according to American Heart Association/National Heart, Lung and Blood Institute (AHA/NHBL) criteria with body mass index (BMI) substituted for waist circumference.

RESULTS

Among the subjects, 31.6% had diabetes, 46.9% had metabolic syndrome, and mean log (FABP4) levels showed significantly higher levels in subjects with diabetes. Among the subjects, 42.4% had normal coronary vessel, 34.6% had 1-vessel disease, 13.7% had 2-vessel disease, and 9.4% had 3-vessel disease. Among the parameters, mean age, fasting glucose, and log (FABP4) levels increased significantly as the numbers of stenotic vessel increased from normal to 3-vessel disease, and for FABP4, these significances showed a consistent trend for difference after adjustment for age, gender, BMI, and fasting glucose (P=0.072). Mean log (FABP4) level showed lower values in subjects taking aspirin, and higher values in subjects taking statin and anti-hypertensive drugs.

CONCLUSIONS

Serum FABP4 levels increased as the numbers of stenotic coronary artery increased, although these differences were attenuated after adjustment for age and fasting glucose levels. Various anti-atherogenic medications showed different effects on the serum FABP4 levels, which need further investigation.

Anxiolytic-like effects of sanjoinine A isolated from Zizyphi Spinosi Semen: possible involvement of GABAergic transmission

This experiment was performed to investigate the anxiolytic-like effects of sanjoinine A, one of the major alkaloid compounds in Zizyphi Spinosi Semen (ZSS), by using experimental paradigms of anxiety in comparison with a known anxiolytic, diazepam. Sanjoinine A (2.0 mg/kg) increased the percentage of time spent on the open arms and the number of open arms entries in the elevated plus-maze test, increased the number of head dips in the hole-board test, and increased the percentage of time spent in the center zone and the center zone locomotor distance in the open field box experiment. However, sanjoinine A (0.5, 1.0, 2.0 mg/kg) had no effect on locomotor activity, while diazepam (2.0 mg/kg) significantly reduced locomotor activity. Sanjoinine A (0.5, 1.0, 2.0 mg/kg) did not influence the grip force in the grip strength meter test either. Molecular experiments showed that sanjoinine A (2.0, 5.0 microM) increased chloride influx in cultured cerebellar granule cells. In addition, sanjoinine A (5.0 microM) treatment resulted in over-expression of alpha- and gamma-subunits of GABA(A) receptors and glutamic acid decarboxylase (GAD65/67) in cultured cerebellar granule cells. It is concluded that sanjoinine A may have anxiolytic-like effects in the elevated plus-maze, hole-board test and open field test, and these effects may be mediated by GABAergic transmission.

Protective effects of sanjoinine A against N-methyl-D-aspartate-induced seizure

Sanjoinine A is a component of the alkaloid fraction of Zizyphi Spinosi Semen. This experiment was performed to investigate whether sanjoinine A acts as an anticonvulsive in the N-methyl-D-aspartate (NMDA)-induced experimental seizure model. We also examined whether it protects against seizure-form electroencephalogram (EEG) alterations induced by NMDA in vivo and/or cell killing due to NMDA in cultured cerebellar granule cells. Administration of sanjoinine A increased the survival rate and the latency of seizure onset, and decreased the seizure scores and the weight-loss induced by NMDA in mice, in a dose-dependent manner. In addition, sanjoinine A blocked seizure-form EEG alterations induced by NMDA and inhibited NMDA-induced cell killing in cultured rat cerebellar granule cells, measured by both the trypan blue exclusion test and the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. Moreover, sanjoinine A inhibited the elevation of intracellular calcium influx induced by NMDA, which was measured using a fluorescent dye, Furo 3-AM. It is suggested that sanjoinine A protects against NMDA-induced seizures by inhibiting intracellular calcium influx.