Homocystinuria is an inborn error on the pathway of the methionine metabolism. It is mainly caused by a cystathionine B-synthase deficiency in the brain or liver. Homocystinuria is biochemically characterized by: 1) an increase of the homocystine and methionine concentration in the plasma; and 2) a decrease of the cystine with an increased excretion of homocystine in the urine. The clinical manifestations of this autosomal recessive disorder include: ectopoia lentis, skeletal abnormalities, high incidence of thromboembolism and high frequency of mental retardation. We have been experiencing a case of a 10 year old female patient who has suffered from homocystinuria. She has undergone mental retardation, poor vision caused by ocular complications and Marfanoid feautures.
Brain ; Child ; Cystathionine ; Cystine ; Ectopia Lentis* ; Female ; Homocystine ; Homocystinuria* ; Humans ; Incidence ; Intellectual Disability ; Liver ; Metabolism ; Methionine ; Plasma ; Thromboembolism

We identified a neuroprotective single fraction among 62 ones of hexane extract from Uncaria sinensis (JGH43IA) and investigated its effects and mechanisms in primary cortical neurons. Pretreatment with JGH43IA showed a significantly increase cell viability in a dose-dependent manner with a decrease in the lactate dehydrogenase release. When we performed morphological assay and flow cytometry to determination of the type of cell death, pretreatment with JGH43IA showed a significant reduction of glutamate-induced apoptotic cell death. Then we explored the downstream signaling pathways of N-methyl-D-aspartate receptor (NMDAR) with calpain activation to elucidate possible pathways of neuroprotection by JGH43IA. Pretreatment with JGH43IA exhibited a significant attenuation of NMDAR GluN2B subunit activation and a decrease in active form of calpain 1 leading to subsequent cleavage of striatal-enriched protein tyrosine phosphatase (STEP). In addition, pretreatment with JGH43IA showed a marked increase of cAMP responsive element binding protein. These results suggest that JGH43IA may have neuroprotective effects through down-regulation of NMDAR GluN2B subunit and calpain 1 activation, and subsequent alleviation of STEP cleavage. This single fraction from U. sinensis might be a useful therapeutic agent for brain disorder associated with glutamate injury.
Brain Diseases ; Calpain ; Carrier Proteins ; Cell Death ; Cell Survival ; Down-Regulation ; Flow Cytometry ; Glutamates ; Glutamic Acid ; L-Lactate Dehydrogenase ; N-Methylaspartate ; Neurons* ; Neuroprotective Agents* ; Protein Tyrosine Phosphatases ; Receptors, N-Methyl-D-Aspartate ; Uncaria*

PURPOSE: Glutamate and aspartate are the excitatory amino acid neurotransmitters and NMDA (N-methyl-D-aspartate) is one of their major receptors. NMDA agonist may sti mulate serotonergic nervous system that inhibit the penile erection as well as induce the penile erection. We investigate the effects of NMDA agonist on serotonin release from hippocampus. MATERIALS AND METHODS: The slices of hippocampus were incubated in a buffer con taining 0.1mM [(3)H]5-hydroxytryptamine (5-HT) for uptake in the male rat. The release of 5-HT into the buffer during each 10 minutes period was measured and the radio activities in each buffer and the tissue were counted. After 50 min from the initiation, NMDA agonist were administered at 6th and 7th 10 min period respectively. The changes of 5-HT release were expressed as percent values compared to the 5th 10 min period. Tetrodotoxin was used to determine the possible involvement of interneuron on the action of these neurotransmitters. RESULTS: A steady release of 5-HT was observed up to 100 minutes after the rapid release during the first 40 minutes. Treatment of tetrodotoxin (10(-6)M) did not change the spontaneous release of 5-HT. The 5-HT released during 10 and 20 minutes of NMDA agonist (10(-4M)) treatment significantly higher than those of control group. The increase of 5-HT release by NMDA agonist was blocked by pretreatment with tetro dotoxin. The release of 5-HT was increased by NMDA agonist and this response was blocked by tetrodotoxin. CONCLUSIONS: NMDA agonist increases the release of 5-HT through the activation of the interneurons and these results suggest that NMDA agonist may stimulate the serotonergic nervous system that inhibit the penile erection as well as inducing the penile erection.
Animals ; Aspartic Acid ; Excitatory Amino Acids ; Glutamic Acid ; Hippocampus* ; Humans ; Interneurons ; Male ; N-Methylaspartate* ; Nervous System ; Neurotransmitter Agents ; Penile Erection ; Rats* ; Serotonin* ; Tetrodotoxin

Several decades of research attempting to explain schizophrenia regarding dopamine hyperactivity hypothesis have produced disappointing results. New hypotheses focusing on serotonin-dopamine interactions and hypofunction of the NMDA glutamate transmitter system have been emerging as potentially more promising concepts. The next generation of treatments for schizophrenia, whether they are based on dopamine, serotonin, or glutamate etc., should be effective on negative symptoms and cognitive deficits as well as positive symptoms. In this article, I review the brief overview of these hypotheses and new drugs based on the hypotheses.
Dopamine ; Glutamic Acid* ; N-Methylaspartate ; Receptors, Glutamate* ; Schizophrenia ; Serotonin

Hypoxia (low oxygen level) is an important feature during infections and affects the host defence mechanisms. The host has evolved specific responses to address hypoxia, which are strongly dependent on the activation of hypoxia-inducible factor 1 (HIF-1). Hypoxia interferes degradation of HIF-1 alpha subunit (HIF-1α), leading to stabilisation of HIF-1α, heterodimerization with HIF-1 beta subunit (HIF-1β) and subsequent activation of HIF-1 pathway. Apical periodontitis (periapical lesion) is a consequence of endodontic infection and ultimately results in destruction of tooth-supporting tissue, including alveolar bone. Thus far, the role of HIF-1 in periapical lesions has not been systematically examined. In the present study, we determined the role of HIF-1 in a well-characterised mouse periapical lesion model using two HIF-1α-activating strategies, dimethyloxalylglycine (DMOG) and adenovirus-induced constitutively active HIF-1α (CA-HIF1A). Both DMOG and CA-HIF1A attenuated periapical inflammation and tissue destruction. The attenuation in vivo was associated with downregulation of nuclear factor-κappa B (NF-κB) and osteoclastic gene expressions. These two agents also suppressed NF-κB activation and subsequent production of proinflammatory cytokines by macrophages. Furthermore, activation of HIF-1α by DMOG specifically suppressed lipopolysaccharide-stimulated macrophage differentiation into M1 cells, increasing the ratio of M2 macrophages against M1 cells. Taken together, our data indicated that activation of HIF-1 plays a protective role in the development of apical periodontitis via downregulation of NF-κB, proinflammatory cytokines, M1 macrophages and osteoclastogenesis.
Alveolar Bone Loss ; metabolism ; prevention & control ; Amino Acids, Dicarboxylic ; pharmacology ; Animals ; Cytokines ; metabolism ; Down-Regulation ; Gene Expression ; drug effects ; Hypoxia-Inducible Factor 1, alpha Subunit ; physiology ; Macrophages ; physiology ; Mice ; NF-kappa B ; metabolism ; Osteogenesis ; physiology ; Periapical Periodontitis ; metabolism ; prevention & control ; Real-Time Polymerase Chain Reaction ; X-Ray Microtomography

The purpose of this study was, first, to devise a new model for topical application of excitatory amino acids(EAAs) to rat cerebral cortex that successfully and repeatdly initiate the cortical spreading depression(CSD). Then, by using this model, six major EAAs that are known to act on single or multiple subtypes of EAA receptor were examined; glutamate, kainate, aspartate, N-methyl-D-aspartate(NMDA), quisqualate, and alpha-amino-3-hydroxy-5-methyl-4-isoxazoie-proprite(AMPA). Through the model, with a cone-shaped well buried in 1.5mm depth of the cerebral cortex, these chemical agents were topically applied to the cortical gray matter. A total of 50 Sprague-Dawley rats were used and divided into seven groups including the sham group. Doses of each EAA between 10(-7) and 10(-4)M concentrations were escalated for triggering the CSD and its rate of consistency in triggering was also evaluated. In the overall results. CSDs were repeatedly initiated in all experimental groups with relatively consistent rates. Duration of CSDs were 1-4 minutes(mean 2.2+/-1.4) and amplitudes were 20-40mV. Effective dose(50)(ED(50)), that trigger over 50% of CSD was 10(-5)M(n=8) for glutamate, 10(-7)M(n=8) for aspartate, 10(-5)M(n=7) for AMPA, 10(-5)M(n=7) for quisqualate, and 10(-4)M(n=7) for NMDA and kainate group. Among those acting on the single receptor, AMPA was shown to be the most effective in triggering CSD, and NMDA, and kainate were in descending orders. Aspartate that was known to act on multiple EAA receptors, showed the highest rate of triggering CSD among all groups, but glutamate, known to act on all receptors of its subtypes, showed the most consistent rate of triggering CSD at dose escalation. These results revealed that those EAA acting on multiple receptors, namely aspartate and glutamate, showed the highest and most consistent rate of triggering CSD. Among those acting on single channel of receptors. AMPA was the most effective, although its consistency and rate of triggering of CSD was somewhat lower than.
alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid ; Animals ; Aspartic Acid ; Cerebral Cortex ; Cortical Spreading Depression* ; Excitatory Amino Acids* ; Glutamic Acid ; Kainic Acid ; N-Methylaspartate ; Quisqualic Acid ; Rats ; Rats, Sprague-Dawley ; Receptors, AMPA

No abstract available.
Homocystine ; Homocystinuria*

Orthostatic hypotension is most common in elderly people, and its prevalence increases with age. Attenuation of the vestibulo-sympathetic reflex (VSR) is commonly associated with orthostatic hypotension. In this study, we investigated the role of glutamate on the vestibulo-solitary projection of the VSR pathway to clarify the pathophysiology of orthostatic hypotension. Blood pressure and expression of both pERK and c-Fos protein were evaluated in the nucleus tractus solitarius (NTS) after microinjection of glutamate into the medial vestibular nucleus (MVN) in conscious rats with sodium nitroprusside (SNP)-induced hypotension that received baroreceptor unloading via sinoaortic denervation (SAD). SNP-induced hypotension increased the expression of both pERK and c-Fos protein in the NTS, which was abolished by pretreatment with glutamate receptor antagonists (MK801 or CNQX) in the MVN. Microinjection of glutamate receptor agonists (NMDA or AMPA) into the MVN increased the expression of both pERK and c-Fos protein in the NTS without causing changes in blood pressure. These results indicate that both NMDA and AMPA receptors play a significant role in the vestibulo-solitary projection of the VSR pathway for maintaining blood pressure, and that glutamatergic transmission in this projection might play a key role in the pathophysiology of orthostatic hypotension.
Aged ; Animals ; Blood Pressure ; Denervation ; Excitatory Amino Acid Antagonists ; Glutamic Acid* ; Humans ; Hypotension* ; Hypotension, Orthostatic ; Microinjections ; N-Methylaspartate ; Nitroprusside ; Pressoreceptors ; Prevalence ; Rats* ; Receptors, AMPA ; Receptors, Glutamate ; Reflex ; Sodium* ; Solitary Nucleus ; Vestibular Nuclei

To investigate the mechanism of the excitatory signal transmission, the effects of N-methyl-D-aspartate(NMDA, ionotropic glutamate agonist) and kynurenic acid(glutamate antagonist) on catfish retinal neurons were explored using conventional intracellular recording techniques. Horizontal cells were depolarized by glutamate, kainate, quisqualate, and NMDA but gyperpolarized by kynurenate. Transient components of both ON-and OFF-bipolar cells were reduced either by glutamate or by NMDA. Kynurenate suppressed sustained components of the third-order neurons or OFF-bipolar cells. Furthermore, kynurenate blocked the depolarizing actions of NMDA on horizontal cells and ON-sustained cells with large ON-transient components. The results suggest that NMDA would exert a tonic depolarization in the horizontal cells and the 3rd-order neurons, and there might be a preferential suppression on the a NMDA receptors by kynurenic acid in the catfish retina.
Catfishes ; Glutamic Acid ; Kainic Acid ; Kynurenic Acid* ; N-Methylaspartate ; Neurons* ; Quisqualic Acid ; Receptors, N-Methyl-D-Aspartate ; Retina* ; Retinal Neurons

The present study was undertaken to characterize homocysteic acid (HCA)-and cysteic acid (CA)mediated formation of inositol phosphates (InsP) in primary culture of rat cerebellar granule cells. HCA and CA stimulated InsP formation in a dose-dependent manner, which was prevented by the N-methyl-D-aspartate (NMDA) receptor antagonist D,L-2-amino-5-phosphopentanoic acid (APV). CA-, but not HCA-, mediated InsP formation was in part prevented by the metabotropic glutamate receptor antagonist alpha-methyl-4-carboxyphenylglycine ((+/-)-MCPG). Both HCA- and CA-mediated increases in intracellular calcium concentration were completely blocked by APV, but were not altered by (+/-)-MCPG. CA-mediated InsP formation was in part prevented by removal of endogenous glutamate. In contrast, the glutamate transport blocker L-aspartic acid-beta-hydroxamate synergistically increased CA responses. These data indicate that in cerebellar granule cells HCA mediates InsP formation wholly by activating NMDA receptor. In contrast, CA stimulates InsP formation by activating both NMDA receptor and metabotropic glutamate receptor, and in part by releasing endogenous glutamate into extracellular milieu.
Animals ; Calcium ; Cysteic Acid* ; Glutamic Acid ; Inositol Phosphates* ; Inositol* ; N-Methylaspartate ; Rats* ; Receptors, Metabotropic Glutamate