• The Korean Journal of Physiology and Pharmacology
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• v.11 no.4
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• pp.155-161
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• 2007

In order to characterize the role of sympathetic activity in obesity, we repeatedly assessed sympathetic activity via power spectral analyses of heart rate variability in the same subjects at 7, 11, 25, and 60 weeks, using monosodium glutamate (MSG)-induced obese and control rats. The effects of lower sympathetic activity on obesity were also evaluated. Fat mass in MSG rats was already higher at 7 weeks, but the sympathetic activity did not differ between 7 and 25 weeks. Between 25 and 60 weeks, the increase in fat mass, food efficiency, and body weight gain was higher in MSG rats. The increase in sympathetic activity between 25 and 60 weeks and sympathetic activity at 60 weeks were lower in MSG rats. Fat mass at 60 weeks was inversely correlated with changes in sympathetic activity between 25 and 60 weeks. Reduced plasma epinephrine levels by bilateral adrenal demedullation induced increase of fat mass. In, an attenuated increase of sympathetic activity with age may partly be responsible for aggravated obesity in MSG rats. Additionally, reduced sympathetic activity per se induced obesity in rats. These results suggest that lower sympathetic activity contributes to obesity in rats.

• YAKHAK HOEJI
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• v.35 no.5
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• pp.384-388
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• 1991

To explore the effect of monosodium-L-glutamate(MSG) on CCI$_{4}$-damaged liver in Wister male rat, 5% MSG solution as drink water were administered after S.C. injection of 0.1 mg/kg CC1$_{4}$ twice a week for 4 weeks. After last administration of MSG, heptic glutathione(GSH) dependent system was assayed. It showed that MSG increased significanly hepatic glutathione(GSH) and glutathione peroxidase(GSH$_{px}$), but decreased glutathione-S-transferase(GST) acivity in normal rats. MSG increased significantly the GSH$_{px}$ and GST activities in rats with CCI$_{4}$-induced liver damage. These results indicate that decrease of GSH dependent systems in CC1$_{4}$ liver injury might be partially elevated by coadministration of MSG.

• Journal of Veterinary Clinics
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• v.16 no.2
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• pp.265-271
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• 1999

These experiments were performed to investigate the effect of saline, monosodium L-glutamate(MSG), MSG-phenylalanine, and/or phenylalanine on TH-immunoreactivity in arcuate nucleus of hypothalamus and hind limb area of cerebral cortex in rats using the immunohistochemical methods. The result were as follows: 1. TH-immunoreactive neurons in hind limb area of cerebral cortex and arcuate nucleus of hypothalamus were decreased in MSG treated group compared to the saline treated group and also lesions in arcuate nucleus and median eminence of hypothalamus were increased with MSG treatment 2. TH-immunoreactive neurons in median eminence and arcuate nucleus were increased in phenylalanine treated group compared to the saline treated group and also neurons were more increased in lamina V of hind limb area of cerebral cortex with phenylalanine treatment. 3. TH-immunoreactive neurons in median eminence and arcuate nucleus were decreased in MSG-phenylalanine treated group compared to the phenylalanine treated group and increased compared to the MSG treated group. In lamina V of hind limb area of cerebral cortex, TH-immunoreactive neurons were more decreased in MSG-phenylalanine treated group than that of the phenylalanine treated group, and more increased than that of MSG treated group. These experiments indicated that TH-immunoreactive neurons in hypothalamus and cerebral cortex were increased due to the activation of phenylalanine and decreased by suppressing activation of phenylalanine through MSG treatment.

• Journal of Food Hygiene and Safety
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• v.30 no.1
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• pp.120-125
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• 2015

The objective of this study is to investigate the effect of MSG on cognitive function and anxiety by the T-maze and elevated-plus-maze test and repeated oral dose toxicity in SD rat of MSG. The rats were treated with MSG of control group, low group (3 g/kg) and high group (5 g/kg) intragastrically for 4 weeks, respectively. We examined the body weight, the clinical signs, T-maze, Elevated-plus-maze, hematological analysis and serum biochemical analysis, we also observed the histopathological changes of liver, kidney in rats. No significant differences in body weights, biochemical analysis and histopathological observations between control and MSG treatment group were found. In the elevated plus maze (EPM), MSG-treatment group has more open arm visited than controls. MSG-treatment group has been more activated in T-maze test. These data indicate the continuous high MSG intake could be increased the anxiety and could be decreased cognitive ability. In conclusion, MSG is physiologically safety, but high MSG intake could be increased the anxiety and could be decreased cognitive ability in juvenile rat.

• The Korean Journal of Physiology and Pharmacology
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• v.14 no.4
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• pp.213-221
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• 2010

The hypothalamic-pituitary-adrenal (HPA) axis is the primary endocrine system to respond to stress. The HPA axis may be affected by increased level of corticotrophin-releasing factors under chronic stress and by chronic administration of monosodium glutamate (MSG). The purpose of this study was to investigate whether chronic MSG administration aggravates chronic variable stress (CVS)-induced behavioral and hormonal changes. Twenty-four adult male Sprague-Dawley rats, weighing 200~220 g, were divided into 4 groups as follows: water administration (CON), MSG (3 g/kg) administration (MSG), CVS, and CVS with MSG (3 g/kg) administration (CVS＋MSG). In addition, for the purpose of comparing the effect on plasma corticosterone levels between chronic stress and daily care or acute stress, 2 groups were added at the end of the experiment; the 2 new groups were as follows: naive mice (n=7) and mice exposed to restraint stress for 2 h just before decapitation (A-Str, n=7). In an open field test performed after the experiment, the CVS＋MSG group significant decrease in activity. The increase in relative adrenal weights in the CVS and CVS＋MSG group was significantly greater than those in the CON and/or MSG groups. In spite of the increase in the relative adrenal weight, there was a significant decrease in the plasma corticosterone levels in the CVS＋MSG group as compared to all other groups, except the naive group. These results suggest that impaired HPA axis function as well as the decrease in the behavioral activity in adult rats can be induced by chronic MSG administration under CVS rather than CVS alone.

• Journal of Korean Medicine Rehabilitation
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• v.18 no.1
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• pp.33-46
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• 2008

Objectives : Obesity is a metabolic disease resulted from various causes including nutritional disproportion, hormonal imbalance, and hypothalamic nuclei disorder. Samhwang-tang(Sanhuang-tang, SHT) is composed of 5 herbs (Ephedrae Herba, Scutellariae Radix, Typhae pollen, Acori Rhizoma and Ansu Semen) and is frequently used for obese patients. This study investigated anti-obesity effects of SHT on the rats. Methods : Obesity was induced by high fat diet (HFD), monosodium L-glutamate injection (MSG) and ovariectomy (OVX) in the Sprague-Dawley rats. Water extract of SHT was treated for 2 weeks, then changes of body weight gain and epididymal fat cell size were measured. In OVX animals, c-Fos and neuropeptide Y (NPY) expressions in hypothalamic nuclei were observed with immunohistochemistry. Results : SHT treatment demonstrated significant decrease of body weight gain in obesity induced by HFD and OVX, but not in obesity induced by MSG. SHT treatment demonstrated significant decrease of fat cell size in obesity induced by HFD, but not in obesity induced by MSG. On c-Fos and NPY expressions in hypothalamic nuclei, SHT treatment resulted significant decrease of immuno-reactivity of c-Fos and NPY in obesity induced by OVX. Conclusions : These results suggest that SHT has a weight loss effect against obesity induced by nutritional disproportion of diet intake and hormonal imbalance, especially without central nervous system disorder.

• YAKHAK HOEJI
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• v.36 no.1
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• pp.73-79
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• 1992

To achieve better understanding of the effects of monosodium-L-glutamate(MSG) against $CCl_4$ fatty liver in Wister male rats, 5% MSG solution was given as drinking water and $CCl_4$ 0.1 ml/kg was injected subcutaneously twice a week for four weeks. It was showed that increased hepatic phospholipid and hepatic triacylglycerol levels by $CCl_4$ challenge were significantly decreased by additionnal MSG, respectively. However, MSG had no apparent effect on the elevated hepatic cholesterol level in the presence of $CCl_4$. Histologically, additional MSG markedly inhibited fatty degeneration, spotty necrosis, inflammation and periportal vascular proliferation manifested by $CCl_4$. respectively. These results indicated that effects of MSG against $CCl_4$ induced-fatty liver appeared to be involved with partial restoration of altered hepatic lipid composition.

• Parasites, Hosts and Diseases
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• v.36 no.2
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• pp.127-132
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• 1998

Immunotherapy has been used in support of trimethoprim-sulfamethoxazole treatment for Pneumocvstis corinii pneumonia. The present study investigated the therapeutic or preventive effects of heterogeneous hyperimmune IgG antibody (HIA) in experimental rats. Their immunity was suppressed by steroid injection, and they were also injected peritoneally with HIA which reacted with 40-55, 92, 116, and 200 kDa bands of the crude antigen. All rats were infected by p. ccrinii and the cystic forms on lung impression smears were counted. The count was 20.5-76.5 (mean 52.5 ± 19.)1 in those which received steroid only, but decreased to 6.0-21.0 (mean 13.5 : 10.6) in those of group 3 which received HIA for the same duration. In other groups, the mean count ranged from 29.9 t 32.9 to 54.1 t 47.7, and in those which received 13.7 mg HIA the reduction effect was greater than in those which received 6.8 mg or 20.5 mg HIA. The present finding confirmed that in rats during the early stage of infection, the heterogeneous HIA to MSG antigen bands had a partial effect on p. cori,nii pneumonia, both prophylactically and therapeutically.

• Parasites, Hosts and Diseases
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• v.38 no.3
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• pp.151-158
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• 2000

Pneumocystis carinii is a major opportunistic pathogen which has been found in the lungs of a wide variety of mammalian host species, and the fact suggests the possibility of intraspecific variation. Until now, P. carinii from different mammalian species are differentiated as subspecies, and the rats are known to be infected by two subspecies. The present study investigated genetic heterogeneity of P. carinii isolates from two strains of rats in Korea and China by molecular karyotyping, RFLP and sequencing analysis. Karyotypes of P. carinii were grouped into three, two from two strains of rats In Korea and one from rats in China. However RFLP of PCR product of ribosomal and MSG gene of the P. carinii isolates showed same pattern. The sequence homology rates of ${\alpha}-tubulin$ DNA of the P. carinii isolates were 96% in Seoul Wistar rats, 93% in Seoul Sprague-Dawley rats, and 85% in Chinese Sprague-Dawley rats. The present finding confirmed that P. carinii from rats in Korea are grouped into two karyotype strains which are different from that of P. carinii from rats in China. The Chinese isolate shows a little different sequences of ${\alpha}-tubulin$ DNA.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1996.04a
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• pp.246-246
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• 1996

The glucuronide conjugates of morphine have been claimed to exert significant neuropharmacological effects. Morphine-6-glucuronide (M6G) may be a potent opioid agonist in vivo, and morphine-3-glucuronide (M3G) may act as a weak opioid antagonist. The present study addressed the permeability of the blood-brain barrier (BBB) for these metabolites compared to morphine. Tracers were prepared by enzymatic glucuronidation of U-methyl-$^3$H]-morphine. Brain uptake in rats was measured by the internal carotid artery perfusion technique and after i.v. bolus injections. In the perfusion experiments morphine showed a permeability-surface area product (PS) of 3.52${\pm}$0.61 ${\mu}$L min$\^$-1/ g$\^$-1/ Uptake seems to be mediated by passive diffusion and was not saturable by 100 ${\mu}$M morphine in the perfusate. The BBB permeability of [$^3$H]-M3G and [$^3$H]-M6G was too low to be quantified after 5 min of perfusion. Brain uptake of [$^3$H]-M3G and [$^3$H]-M6G 60 min after i.v. bolus injection reached 0.0060${\pm}$0.0003 and 0.0030${\pm}$0.0005% injected dose per g, respectively. From these brain concentrations and from the corresponding plasma concentration - time curves, BBB PS values of 0.14${\pm}$ 0.02 ${\mu}$L min$\^$-1/g$\^$-1/ and 0.11 ${\pm}$ 0.01 ${\mu}$L min$\^$-1/g$\^$-1/, respectively, were calculated. The ratio of BBB PS values is complementary to the analgesic potencies of morphine and M6G after different routes of administration. The low PS of MSG explains, why it is approximate]y equipotent to morphine after systemic injection, although it is about 2 orders of magnitude more potent than morphine after administration directly into the central nervous system.