• Proceedings of the PSK Conference
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• 2001.10a
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• pp.195.2-195.2
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• 2001

• The Korean Journal of Zoology
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• v.34 no.4
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• pp.491-499
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• 1991

The present experiment was carried out 1) to study the developmental topography of GnRH neuronal system and 2) to characterize the cellular localization of GnRH neurons in the prenatal brain development of the rat. At embryonic day (I) 14.5, immunoreactive cell bodies of GnRH were first seen in the nasal septum and in the ganglion terminate located in the ventral protion of the caudal olfactory bulb. Two days later (E 16.5), GnRH-containing neurons were observed at the level of olfactory tubercle and diagonal band of Broca, which is the first appearance in the intracerebral region. From 118.5, the topographic pattern of immunoreactive GnRH perikarya was similar to that of adult rats. The present data suggest that GnRH neurons were originated from the nasal septum and gradually extended to the hvpothalamic regions with increasing fetal age.

• Molecules and Cells
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• v.22 no.1
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• pp.8-12
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• 2006

Neuron-derived orphan receptor (NOR-1) is a member of the thyroid/steroid receptor superfamily that was originally identified in forebrain neuronal cells undergoing apoptosis. In addition to apoptotic stimuli, activation of several signal transduction pathways including direct neuronal depolarization regulates the expression of NOR-1. In this study we tested whether the expression of NOR-1 is changed following transient ischemic injury in the adult rat brain. NOR-1 mRNA increased rapidly in the dentate gyrus of the hippocampal formation and piriform cortex 3 h after transient global ischemia and returned to basal level at 6 h. On the other hand, oxygen-glucose deprivation of cultured cerebral cortical neurons did not alter the expression of NOR-1. These results suggest that expression of NOR-1 is differentially regulated in different brain regions in response to globally applied brain ischemia, but that hypoxia is not sufficient to induce its expression.

• Biomolecules & Therapeutics
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• v.6 no.1
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• pp.20-24
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• 1998

In the present study, we tested whether lead intoxication induces change of the thiamine content and the seizure threshold in rats and the changes of seizure threshold are related to the changes of thiamine status. It was also tested whether administration of excessive thiamine could reverse the toxic manifestation of lead in rats. Four groups of Wistar rats were prepared: 1) control group, 2) lead treated group, 3) lead plusthiamine treated group, and 4) thiamine deficient group. Each group of animals was divided into three subgroups based on age: 3, 7 and 16 weeks. In each group, thresholds of electroshock seizure and thiamine contents in brain regions including telencephalon, brain stem, cerebellum were measured. Thiamine contents in brain regions of the lead treated group were significantly lower than those of the control group and thiamine treatment reversed the decrease back to the control level. Thresholds of the electroshock seizure of the lead treated group in 3, 7 week old rats and those of thiamine deficient group in 3 week old rats were significantly lower than those of the control group. These observations were reversed by the supplementation with thiamine. These results from the present study suggest that increased seizure sensitivity induced by lead intoxication in rats may be mediated at least in part through the changes of thiamine status.

• Toxicological Research
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• v.14 no.4
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• pp.495-500
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• 1998

The effect of acute toluene exposure on behaviour and monoamine concentrations in the various brain regions were investigated in the rat. Toluene was adminstered via inhalation to rats at concentrations of 0, 1000, 10000, 40000 ppm for 20 min. During exposure to toluene, spontaneous locomotor activity was counted. After exposure, animals were sacrificed instantly and brains were separated. Regional concentratons of brain monoamines (norepinephrine, NE; dopamine, DA; 5- hydroxytryptamine, 5-HT) and its metabolites (3,4-dihydroxyphenylacetic acid, DOPAC; homovanillic acid, HVA; 5-hydroxyindole-3-acetic acid, 5-HIAA) were determined. The changes in locomotor activity during toluene exposure depended on the toluene concentration. At 1000 ppm concentration, spontaneous locomotor activity increased initially and thereafter decreased. At higher concentrations (10000 ppm and 40000 ppm), spontaneous locomotor activity decreased and eventually ceased. A regional analysis of VA, NE, 5-HT, VOPAC, HVA, and 5-HIAA indicated a significant decrease in VA concentrations in cerebellum and striatum while NE and 5-HT concentrations were significantly increased in the cerebellum and cortex. 5-HIAA concentrations were significantly increased in all brain regions. DOPAC concentrations were significantly increased in cerebellum and cortex while decreased in striatum. These results especially indicated that metabolic conversion of DA to HVA in striatum was highly increased by toluene inhalation. However, It remains to elucidate between behavioural responses and monoamine changes.

• YAKHAK HOEJI
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• v.49 no.4
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• pp.347-354
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• 2005

Lipopolysaccharide (LPS) induces synthesis of several inflammatory cytokines and nitric oxide (NO). NO in brain is involved not only in the regulation of important metabolic pathways via intracellular cyclic GMP-dependent path­ways, but also in neurotoxic damage by reacting with superoxide ion leading to form peroxynitrite radical. Oxidative stress has suggested to be related to the inhibition of NO synthase/cyclic GMP pathway. OQ21 is a new fluorinated quinone compound that is recently known to have inhibitory effects on both NO synthase (NOS) and guanylyl cyclase (GC). In this study, we examined effects of OQ21, other known NOS or GC inhibitors, or an antioxidant, melatonin, on the oxidative stress produced by LPS in rat brain. Oxidative stress was observed by using the 2',7'-dichlorofluorescin diacetate to measure intra-cellular reactive oxygen species (ROS) production and by measuring the formation of thiobarbituric acid reactive substances to measure lipid peroxidation. LPS induced significant increase in both ROS produdction and lipid peroxidation in all brain regions tested (striatum, hippocampus and cortex), which were dissected 6hr after intraperitoneal administration of LPS to rats. Direct striatal injection of two NOS inhibitors, N-nitro-L-arginine methyl ester and diphenyleneiodonium, or a GC inhibitor, IH-[1,2,4]oxadiazolo[4,3-a]quinoxaline-l-one, produced no significant ROS increase. However, OQ21 enhanced ROS formation in striatal tissues from LPS-treated rats. Melatonin decreased LPS-induced ROS formation and decreased ROS formation increased by OQ21 in striatum of LPS-treated rats.

• Animal cells and systems
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• v.7 no.1
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• pp.49-55
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• 2003

The fiber projection from the prefrontal cortex to the locus coeruleus (LC) in the periventricular region was analyzed in rat using anterograde and retrograde tracing methods. Following injection of an anterograde tracer, Phaseolus vulgaris leucoagglutinin (PHA-L), into prelimbic and infralimbic regions of the medial prefrontal cortex, labeled axonal fibers with varicosities were observed bilaterally within the LC, with ipsilateral predominance. Terminal labeling was also observed in the region medial to the nucleus at rostral to middle levels of the LC, whereas axonal labeling in the caudal LC was minimal. Anterogradely-labeled axonal fibers were not found in the subcoerulear region. A retrograde tracer, gold-conjugated and inactivated wheatgerm-agglutinin horseradish-peroxidase (WGA-apo-HRP-gold), was injected into several rostro-caudal levels of the LC. Majority of retrogradely-labeled cells were observed in the prelimbic or infralimbic regions of the medial prefrontal cortex when the injections were made into rostral to middle levels of the LC. Only a few cells were observed in cingulate, dorsal peduncular, orbital, or insular cortices. The present findings suggest that the nucleus LC receives restricted, excitatory inputs from cognitive, emotional, and autonomic centers of the cerebral cortex and might secondarily have influences on widespread brain regions via its diversified monoaminergic innervation.

• Molecules and Cells
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• v.27 no.2
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• pp.263-268
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• 2009

Gamma knife surgery (GKS) is used for the treatment of various human brain disorders. However, the biological effects of gamma ray irradiation on both the target area, and the surrounding tissues are not well studied. The effects of gamma ray exposure to both targeted and untargeted regions were therefore evaluated by monitoring gene expression changes in the unilateral irradiated (60 Gy) and contralateral un-irradiated striata in the rat. Striata of irradiated and control brains were dissected 16 hours post-irradiation for analysis using a whole genome 44K DNA oligo microarray approach. The results revealed 230 induced and 144 repressed genes in the irradiated striatum and 432 induced and 239 repressed genes in the unirradiated striatum. Out of these altered genes 39 of the induced and 16 of the reduced genes were common to both irradiated and un-irradiated tissue. Results of semiquantitative, confirmatory RT-PCR and western blot analyses suggested that ${\gamma}$-irradiation caused cellular damage, including oxidative stress, in the striata of both hemispheres of the brains of treated animals.

• Preventive Nutrition and Food Science
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• v.7 no.3
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• pp.265-272
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• 2002

In this study, we examined the effects of dietary fatty acids on the fatty acid composition of phospholipid fractions in regions of the brain and on behavioral development in rats. The Sprague Dawley rats were fed the experimental diets 3~4 wks prior to the conception. Experimental diets consisted of 10% fat(wt/wt) which were from either safflower oil (SO, poor in $\omega$3 fatty acids), mixed oil MO, P/M/S ratio : 1:1.4:1, $\omega$6/$\omega$3 ratio = 6.3), or mixed oil supplemented with vitamin E (+500 mg/kg diet). At 3 and 9 weeks of age, frontal cortex (FC), corpus striatum (CS), hippocampus (H), and cerebellum (CB) were dissected from the whole brain. The fatty acid content was determined in the different phospholipid fractions: phosphatidylcholine (PC), phosphatidyl-serine (PS), and phosphatidylethanolamine (PE) in the rat brain regions. In the visual discrimination test, the order of the cumulative errors made in Y-water maze test were SO > MO > ME. This suggested that the balanced diet supplemented with vitamin I had the most beneficial effect on learning ability. The overall characteristics of correlation between fatty acids and behavior development were that the frequency of cumulative errors were negatively correlated significantly with monounsaturated fatty acids (MUFAs), ie., 18:1 $\omega$9 and 22:1 $\omega$9. Docosa-hexaenoic acid (22:6 $\omega$3) of PS in frontal cortex (FC) was negatively correlated with the number of errors made in the Y-water maze test.22:5 $\omega$6 PS in hippocampus (H), PC and PE in corpus striatum (CS), PC in cerebellum (CB) were positively correlated with cumulative errors. And these errors were negatively correlated with 20:4 $\omega$ 6 of PE in corpus striatum (CS) and PC in cerebellum (CB). Especially, O1eic acid (18:1 u 9) in all phospholipid fractions (PC, PS, PE) of hippocampus was negatively correlated with the number of errors. These findings demonstrate that the MUFAs were might be essential for proper brain development, especially in hippocampus which is generally thought to be the regions of memory and learning.

• The Korean Journal of Physiology and Pharmacology
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• v.18 no.2
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• pp.121-127
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• 2014

Acupuncture is the process of stimulating skin regions called meridians or acupoints and has been used to treat pain-related symptoms. However, the pain-relieving effects of acupuncture may be different depending on acupoints. In the present study, the effects of acupuncture on behavioral responses and c-Fos expression were evaluated using a formalin test in male Sprague-Dawley rats in order to clarify the analgesic effects of three different acupoints. Each rat received manual acupuncture at the ST36 (Zusanli), SP9 (Yinlingquan) or BL60 (Kunlun) acupoint before formalin injection. Flinching and licking behaviors were counted by two blinded investigators. Fos-like immunoreactivity was examined by immunohistochemistry in the rat spinal cord. Manual acupuncture treatment at BL60 acupoint showed significant inhibition in flinching behavior but not in licking. Manual acupuncture at ST36 or SP9 tended to inhibit flinching and licking behaviors but the effects were not statistically significant. The acupuncture at ST36, SP9, or BL60 reduced c-Fos expression as compared with the control group. These results suggest that acupuncture especially at the BL60 acupoint is more effective in relieving inflammatory pain than other acupoints.