• Biomolecules & Therapeutics
• /
• v.28 no.1
• /
• pp.45-57
• /
• 2020

In the neurovascular unit, the neuronal and vascular systems communicate with each other. O₂ and nutrients, reaching endothelial cells (ECs) through the blood stream, spread into neighboring cells, such as neural stem cells, and neurons. The proper function of neural circuits in adults requires sufficient O₂ and glucose for their metabolic demands through angiogenesis. In a central nervous system (CNS) injury, such as glioma, Parkinson's disease, and Alzheimer's disease, damaged ECs can contribute to tissue hypoxia and to the consequent disruption of neuronal functions and accelerated neurodegeneration. This review discusses the current evidence regarding the contribution of oxygen deprivation to CNS injury, with an emphasis on hypoxia-inducible factor (HIF)-mediated pathways and Notch signaling. Additionally, it focuses on adult neurological functions and angiogenesis, as well as pathological conditions in the CNS. Furthermore, the functional interplay between HIFs and Notch is demonstrated in pathophysiological conditions.

• Journal of fish pathology
• /
• v.7 no.1
• /
• pp.63-70
• /
• 1994

Nitric oxide(NO) has recently been shown to play an important role on central nervous system(CNS) function in mammals. It is synthesized from L-arginine by the enzyme NO synthase. In this study, we examined this enzyme's existence in CNS of rainbow trout(Oncorhynchus mykiss) and described the forms of microglia. astrocytes. and oligodendrocytes. Two forms of microglia are distributed in CNS. one resembling their mammalian counterpart(large microglia : LM). and the other comprising small microglia(SM) with very little cytoplasm. CNS contained astrocytes of a distinct type which form reticular network, but lack connections to capillaries. The oligodendrocyte was generally a much denser cell than the astrocyte. We have detected NOS($1.04{\pm}0.12\;pg/min/mg$) from rainbow trout CNS. It could be inhibited reversibly or irreversibly by $N^{G}MMA$ and EGTA. These result suggest that the formation of NO from L-arginine in CNS is calcium-dependent and a pathway of early evolutionary orgin.

• The Journal of Internal Korean Medicine
• /
• v.30 no.4
• /
• pp.674-684
• /
• 2009

Objectives : In conditions of brain infarction, irreversible axon damage occurs in the central nerve system (CNS), because gliosis becomes a physical and a mechanical barrier to axonal regeneration. Reactive gliosis induced by ischemic injury such as middle cerebral artery occlusion is involved with up-regulation of GFAP and CD81. This study was undertaken to examine the effect of the Gongjin-dan (GJD) on CD81 and GFAP expression and its pathway in the rat brain following middle cerebral artery occlusion (MCAO). Methods : In order to study ischemic injuries on the brain, infarction was induced by MCAO using insertion of a single nylon thread, through the internal carotid artery, into a middle cerebral artery. Cresyl violet staining, cerebral infarction size measurement, immunohistochemistry and microscopic examination were used to detect the expression of CD81 and GFAP and the effect on the infarct size and pyramidal cell death in the brain of the rat with cerebral infarction induced by MCAO. Also, c-Fos and ERK expression were measured to investigate the signaling pathway after GJD administration in MCAO rats. Results : Measuring the size of cerebral infarction induced by MCAO in the rat after injection of GJD showed the size had decreased. GJD administration showed pyramidal cell death protection in the hippocampus in the MCAO rat. GJD administration decreased GF AP expression in the MCAO rat. GJD administration decreased CD81 expression in the MCAO rat. GJD administration induced up-regulation of c-FOS expression compared with MCAO. GJD administration induced down-regulation of ERK expression compared with MCAO. Conclusion : We observed that GJD could suppress the reactive gliosis, which disturbs the axonal regeneration in the brain of a rat with cerebral infarction after MCAO by controlling the expression of CD81 and GFAP. The effect may be modulated by the regulation of c-Fos and ERK. These results suggest that GJD can be a candidate to regenerate CNS injury.

• Parasites, Hosts and Diseases
• /
• v.55 no.3
• /
• pp.267-285
• /
• 2017

Angiostrongylus cantonensis invades the central nervous system (CNS) of humans to induce eosinophilic meningitis and meningoencephalitis and leads to persistent headache, cognitive dysfunction, and ataxic gait. Infected mice (nonpermissive host), admittedly, suffer more serious pathological injuries than rats (permissive host). However, the pathological basis of these manifestations is incompletely elucidated. In this study, the behavioral test, histological and immunohistochemical techniques, and analysis of apoptotic gene expression, especially caspase-3, were conducted. The movement and motor coordination were investigated at week 2 post infection (PI) and week 3 PI in mice and rats, respectively. The cognitive impairs could be found in mice at week 2 PI but not in rats. The plaque-like lesion, perivascular cuffing of inflammatory cells, and dilated vessels within the cerebral cortex and hippocampus were more serious in mice than in rats at week 3 PI. Transcriptomic analysis showed activated extrinsic apoptotic pathway through increased expression of TNFR1 and caspase-8 in mice CNS. Immunohistochemical and double-labeling for NeuN and caspase-3 indicated the dramatically increased expression of caspase-3 in neuron of the cerebral cortex and hippocampus in mice but not in rats. Furthermore, western-blotting results showed high expression of cleaved caspase-3 proteins in mice but relatively low expression in rats. Thus, extrinsic apoptotic pathway participated in neuronal apoptosis might be the pathological basis of distinct behavioral dysfunctions in rodents with A. cantonensis infection. It provides the evidences of a primary molecular mechanism for the behavioral dysfunction and paves the ways to clinical diagnosis and therapy for A. cantonensis infection.

• Journal of Acupuncture Research
• /
• v.18 no.3
• /
• pp.56-68
• /
• 2001

Objective : Functional brain mapping study on acupuncture stimulation using the [14C]2-deoxyglucose([14C]2-DG) autoradiography provides quantitative data and visualized pathway in central nervous system(CNS). We aimed to investigate the neural pathway and spatial distribution of metabolic activity elicited in CNS on electroacupuncture stimulation using [14C]2-DG autoradiography. Methods : The study were divided into three groups by stimulation times. 45-mins stimulation group according to Sokoloffs method, 5-mins stimulation group according to Duncun's method, and 15-mins stimulation group. ;A venous catheter was equipped into right jugular vein. The rats (Sprague-Dawley rats, 230-260g) were kept fastened loosely on a holding platform without anesthesia. Electroacupuncture stimulation (5 ms, 2 Hz, 1~3 mA) were applied on the left Zusanli (ST36) acupoint and [14C]2-DG ($25{\mu}Ci/rat$) injection was performed through the catheter. After sacrifice, the brain and the spinal cord were made to sections for film image. The film images were digitalized as the isotope concentration based upon comparison of optical densities with that of the standards and normalized by the optical density of corpus callosum. Results : 1. 15-mins stimulation group was most effective among 3 experiments. 2. On 15-mins stimulation group, medial geniculate nucleus, intetpeduncular nucleus intermedius, ventral periolivary nucleus, caudal periolivary nucleus, medial superior olive, lateral paragigantocellular nucleus, including hypothalamic arcuate nucleus were increased by more than 25% (at least, p<0.05) by electroacupuncture stimulation. 3. Especially, the metabolism in hypothalamic arcuate nucleus was increased by 90% (p<0.05). 4. The fact that arcuate nucleus of hypothalamus might play a role of interconnection area between ascending and descending pathway of acupuncture stimulation was demonstrated visually. Conclusions : Advanced study on electroacupuncture stimulation elicited significant increase of metabolic activity in various nuclei of hypothalamus will provide the important experimental basis in research of the relationship between electroacupuncture stimulation and internal visceral functions.

• Korean Journal of Pharmacognosy
• /
• v.42 no.2
• /
• pp.175-181
• /
• 2011

Oxidative stress or accumulation of reactive oxygen species (ROS) leads neuronal cellular death and dysfunction, and it contributes to neuronal degenerative disease such as Alzheimer's disease, Parkinson's disease and stroke. Glutamate is one of the major excitatory neurotransmitter in the central nervous system (CNS). Glutamate contributes to fast synaptic transmission, neuronal plasticity, outgrowth and survival, behavior, learning and memory. In spite of these physiological functions, high concentration of glutamate causes neuronal cell damage, acute insults and chronic neuronal neurodegenerative diseases. Heme oxygenase-1 (HO-1) enzyme plays an important role of cellular antioxidant system against oxidant injury. NNMBS020, the water-insoluble fraction of the 70% EtOH extract of root barks of Dictamnus dasycarpus, showed dominant neuroprotective effects on glutamate-induced neurotoxicity in mouse hippocampal HT22 cells by induced the expression of HO-1 and increased HO activity. In mouse hippocampal HT22 cells, NNMBS020 makes the nuclear accumulation of Nrf2 and stimulates extracellular signal-regulated kinase (ERK) pathway. The ERK MAPK pathway inhibitor significantly reduced NNMBS020-induced HO-1 expression, whereas the JNK and p38 inhibitors did not. In conclusion, the water-insoluble fraction of the 70% EtOH extract of root barks of D. dasycarpus (NNMBS020) significantly protect glutamate-induced oxidative damage by induction of HO-1 via Nrf2 and ERK pathway in mouse hippocampal HT22 cells.

• The Journal of Korea CHUNA Manual Medicine
• /
• v.3 no.1
• /
• pp.97-109
• /
• 2002

Objectives : Electroacupuncture(EA) has been suggested as a treatment for stroke rehabilitation. But whether, how much, by what mechanism and when it is effective has not been answered satisfactorily. Therefore it is important to critically review clinical trials and laboratory researches about EA for stroke rehabilitation. Subjectives : We researched various recent sources of EA for stroke rehabilitation such as medical journals and especially tried to review methodologically best randomized controlled trials(RCTs). Results and Conclusions : 1) EA increases brain plasticity, activity, blood flow and secretion of neuropeptides in CNS. 2) EA is significantly effective at the case that more than half of the neural motor pathway is reserved. 3) The acupoints, frequncy and intensity of EA should be determined by patient-specific symptoms of stroke. 4) More studies is needed for merdian functions for stroke rehabilitation.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.25 no.2
• /
• pp.217-226
• /
• 2011

The aim of this study is to identify central neural pathway of neurons following the projection to the large intestine and Hapgok(LI4) which is Won acupoint of the large intestine meridian of hand-yangmyeong. In this experiment, Bartha's strain of pseudorabies virus was used to trace central localization of neurons related with large intestine and acupoint(LI4) which has been known to be able to regulate intestinal function. The animals were divided into 3 groups: group 1, injected into the large intestine; group 2, injected into the acupoint(LI4); group 3, injected into the acupoint(LI4) after severing the radial, ulnar, median nerve. After four days survival of rats, PRV labeled neurons were identified in the spinal cord and brain by immunohistochemical method. First-order PRV labeled neurons following the projection to large intestine, acupoint(LI4) and acupoint(LI4) after cutting nerve were found in the cervical, thoracic, lumbar and sacral spinal cord. Commonly labeled neurons were labeled in the lumbosacral spinal cord and thoracic spinal cord. They were found in lamina V- X, intermediomedial nucleus and dorsal column area. The area of sensory neurons projecting was L5-S2 spinal ganglia and T12-L1 spinal ganglia, respectively. In the brainstem, the neurons were labeled most evidently and consistently in the nucleus tractus solitarius, area postrema, dorsal motor nucleus of vagus nerve, reticular nucleus, raphe nuclei(obscurus, magnus and pallidus), C3 adrenalin cells, parapyramidal area(lateral paragigantocellular nucleus), locus coeruleus, subcoeruleus nucleus, A5 cell group, periaqueductal gray matter. In the diencephalon, PRV labeled neurons were marked mostly in the arcuate nucleus and median eminence. These results suggest that overlapped CNS locations are related with autonomic nuclei which regulate the functions of large intestine-related organs and it was revealed by tracing PRV labeled neurons projecting large intestine and related acupoint(LI4).

• Parasites, Hosts and Diseases
• /
• v.58 no.3
• /
• pp.237-247
• /
• 2020

Dendritic cell is one of the first innate immune cell to encounter T. gondii after the parasite crosses the host intestinal epithelium. T. gondii requires intact DC as a carrier to infiltrate into host central nervous system (CNS) without being detected or eliminated by host defense system. The mechanism by which T. gondii avoids innate immune defense of host cell, especially in the dendritic cell is unknown. Therefore, we examined the role of host PI3K/AKT signaling pathway activation by T. gondii in dendritic cell. T. gondii infection or T. gondii excretory/secretory antigen (TgESA) treatment to the murine dendritic cell line DC2.4 induced AKT phosphorylation, and treatment of PI3K inhibitors effectively suppressed the T. gondii proliferation but had no effect on infection rate or invasion rate. Furthermore, it is found that T. gondii or TgESA can reduce H₂O₂-induced intracellular reactive oxygen species (ROS) as well as host endogenous ROS via PI3K/AKT pathway activation. While searching for the main source of the ROS, we found that NADPH oxidase 4 (NOX4) expression was controlled by T. gondii infection or TgESA treatment, which is in correlation with previous observation of the ROS reduction by identical treatments. These findings suggest that the manipulation of the host PI3K/AKT signaling pathway and NOX4 expression is an essential mechanism for the down-regulation of ROS, and therefore, for the survival and the proliferation of T. gondii.

• Biomolecules & Therapeutics
• /
• v.21 no.2
• /
• pp.107-113
• /
• 2013

Plasminogen activator inhibitor-1 (PAI-1) is a member of serine protease inhibitor family, which regulates the activity of tissue plasminogen activator (tPA). In CNS, tPA/PAI-1 activity is involved in the regulation of a variety of cellular processes such as neuronal development, synaptic plasticity and cell survival. To gain a more insights into the regulatory mechanism modulating tPA/PAI-1 activity in brain, we investigated the effects of proteasome inhibitors on tPA/PAI-1 expression and activity in rat primary astrocytes, the major cell type expressing both tPA and PAI-1. We found that submicromolar concentration of MG132, a cell permeable peptide-aldehyde inhibitor of ubiquitin proteasome pathway selectively upregulates PAI-1 expression. Upregulation of PAI-1 mRNA as well as increased PAI-1 promoter reporter activity suggested that MG132 transcriptionally increased PAI-1 expression. The induction of PAI-1 downregulated tPA activity in rat primary astrocytes. Another proteasome inhibitor lactacystin similarly increased the expression of PAI-1 in rat primary astrocytes. MG132 activated MAPK pathways as well as PI3K/Akt pathways. Inhibitors of these signaling pathways reduced MG132-mediated upregulation of PAI-1 in varying degrees and most prominent effects were observed with SB203580, a p38 MAPK pathway inhibitor. The regulation of tPA/PAI-1 activity by proteasome inhibitor in rat primary astrocytes may underlie the observed CNS effects of MG132 such as neuroprotection.