Acid In Brain Tissue Research Articles

Effects of water extract of the spleen-brain-related mineral drug Shehanshi on mouse sleep

ObjectiveTo investigate the effects of water extract of the spleen-brain-related mineral drug Shehanshi on mouse sleep. MethodsShehanshi water extract was subjected to component analysis via X-ray photoelectron spectroscopy. Then, the effects of low-dose (50 mg kg-1) and high-dose (100 mg kg-1) Shehanshi water extract on mouse sleep were evaluated through behavioral tests such as pentobarbital sodium subthreshold and above-threshold sleep experiments and autonomic activity experiments. Furthermore, transcriptome sequencing and nontarget metabolomics analysis were performed on the spleen and brain tissues of the mice. ResultsThe Shehanshi water extract contains a total of 30 elements and can reduce sleep latency, increase sleep time, and increase the sleep rate of mice. In the open field experiment, the movement distance of the mice decreased, and the central residence time and rest time increased. Immunoinfiltration analysis and immunohistochemical verification of spleen tissue showed that compared with those in the control group, the immune abundance of neutrophils in the administration groups increased (P < 0.05). Transcriptome data analysis revealed that the Atp1b2 gene was located at the intersection of the spleen and brain and was positively correlated with neutrophil expression but negatively correlated with the expression of the metabolite oleic acid in brain tissue. Immunohistochemical results showed that Atp2a3 protein expression decreased and Plcg1 protein expression increased in the high-dose group, and the difference was statistically significant (P < 0.05). The Atp1b2 protein level in the spleen tissue was positively correlated with that in the brain tissue of the mice (R = 0.829, P = 0.038). Western blotting revealed that Atp1b2 protein levels in the brain and spleen increased significantly in the high-dose group (P < 0.05). ConclusionThe mechanism by which Shehanshi water extract influences sleep may be associated with the expression of genes related to the spleen-brain axis and calcium signaling pathways in brain tissues.

Exogenous leptin improves cerebral ischemia-reperfusion-induced glutamate excitotoxic injury in mice by up-regulating GLT-1 and GLAST expression in astrocytes

To investigate the protective effect of exogenous leptin against focal cerebral ischemia-reperfusion (I/R) injury in mice and explore the underlying mechanism. A total of 100 C57BL/6 mice were randomly divided into 5 groups, including a sham-operated group, cerebral I/R model group, and 3 leptin treatment groups with intraperitoneal injections of 0.5, 1.0 or 2.0 leptin immediately after occlusion of the internal carotid artery. At 24 h after reperfusion, neurological function scores of the mice were assessed, and TTC staining was used to determine the area of cerebral infarction. The pathological changes in the cortical brain tissue of the mice were observed using HE staining, and degenerative damage of the cortical neurons were assessed with Fluoro-Jade C staining. The expression of glial fibrillary acidic protein in cortical brain tissues was detected using immunohistochemistry and Western blotting. In another 45 C57BL/6 mice with sham operation, I/R modeling, or leptin (1 mg/kg) treatment, glutamic acid in the cortical brain tissue was detected using glutamate assay, and cortical glutamate-aspartate transporter (GLAST) and glutamate transporter-1 (GLT-1) protein expressions were detected using immunohistochemistry. Compared with the I/R model mice, the leptin-treated mice had significantly lower neurological deficit scores, smaller cerebral infarct area, milder pathologies in the cortical brain tissue, and lessened cortical neuronal damage with normal morphology and less excessive proliferation of the astrocytes. Leptin treatment significantly up-regulated the expressions of GLT-1 and GLAST and lowered the content of glutamic acid in the brain tissue of the I/R mice. Exogenous leptin has obvious neuroprotective effect against cerebral I/R injury in mice, mediated probably by controlling excessive astrocyte proliferation and up-regulating cortical GLT-1 and GLAST expressions to reduce glutamate-mediated excitotoxic injury of the astrocytes.

A new approach towards highly sensitive detection of endogenous N-acetylaspartic acid, N-acetylglutamic acid, and N-acetylaspartylglutamic acid in brain tissues based on strong anion exchange monolith microextraction coupled with UHPLC-MS/MS.

Anovel in-tube solid-phase microextraction coupled withan ultra-high performance liquid chromatography-mass spectrometry method has been established for simultaneous quantification of three crucial brain biomarkers N-acetylaspartic acid (NAA), N-acetylglutamic acid (NAG), and N-acetylaspartylglutamic acid (NAAG). A polymer monolith with quaternary ammonium as the functional group was designed and exhibited efficient enrichment of target analytes through strong anion exchange interaction. Under the optimized conditions, the proposed method displayed wide linear ranges (0.1-80 nM for NAA and NAG, 0.2-160 nM for NAAG) with good precision (RSDs were lower than 15%) and low limits of detection (0.019-0.052 nM), which is by far the most sensitive approach for NAA, NAG, and NAAG determination. Furthermore, this approach has been applied to measure the target analytes in mouse brain samples, and endogenous NAA, NAG, and NAAG were successfully detected and quantified from only around 5mg of cerebral cortex, cerebellum, and hippocampus. Compared with existing methods, the newly developed method in the current study provides highest sensitivity and lowest sample consumption for NAA, NAG, and NAAG measurements, which would potentially be utilized in determining and tracking these meaningful brain biomarkers in diseases or treatment processes, benefiting the investigations of pathophysiology and treatment of brain disorders.

Changes in the Serum and Tissue Levels of Free and Conjugated Sialic Acids, Neu5Ac, Neu5Gc, and KDN in Mice after the Oral Administration of Edible Bird’s Nests: An LC–MS/MS Quantitative Analysis

Edible bird’s nests have a variety of biological activities, the main components of which are sialic acids. Sialic acids are a group of nine-carbon N-acetylated derivatives of neuraminic acid containing a keto group at position C2 and play important roles in many biological processes. To verify whether the oral administration of edible bird’s nests would change the content and distribution of sialic acid components in vivo, a liquid chromatography–mass spectrometry method for the quantitative analysis of sialic acid levels in serum and tissues was developed. In the negative ion mode, the mobile phases consist of 0.1% formic acid in water (A) and acetonitrile (v/v) (B). Isocratic elution was performed with 60% B for 0−15 min. The chromatographic separation was performed on a Morphling HILIC Amide column (2.1 mm × 150 mm, 5 μm) at a flow rate of 0.5 mL min−1. The results showed that the correlation coefficients of the typical calibration curves were all higher than 0.995, exhibiting good linearity. The levels of free and conjugated forms of N-glycolylneuraminic acid (Neu5Gc), N-acetylneuraminic acid (Neu5Ac), and 2-keto-3-deoxy-D-glycero-D-galactonononic acid (KDN) in the serum and different tissues were simultaneously detected after the oral administration of the edible bird’s nests at a daily dose of 300 and 700 mg Kg−1 for seven days in mice. Our study found that the oral administration of edible bird’s nests can significantly increase the concentration of total sialic acids (Neu5Gc + Neu5Ac + KDN) in serum and spleen and lungs tissues, which may be related to the anti-inflammatory and immune function of edible bird’s nest, but further studies are needed to verify this. Neu5Ac was the dominant sialic acid in brain tissue, and Neu5Gc was the dominant sialic acid in serum and other tissues, including heart, liver, spleen, lungs, and kidney. Moreover, we found that the forms of Neu5Ac and Neu5Gc were mainly conjugated in all groups except liver tissue. In conclusion, the method we established had good linearity and accuracy; it allowed the analytes to be effectively separated from the matrix and endogenous substances in serum or tissues, so it could effectively detect the distribution and concentration of free and conjugated forms of sialic acids in serum and tissues, which was beneficial to the research and exploitation of edible bird’s nests and sialic acids.

Untargeted UHPLC-MS deferential screening method and targeted UHPLC-MS/MS quantitative method for the determination of amino acids in mouse brain tissue

An untargeted UHPLC-MS method was developed for the preliminary screening of differential amino acids between two mouse brain tissue samples, and a targeted UHPLC-MS/MS method was developed for the quantitative determination of amino acids in mouse brain tissue samples. The sample processing procedure, chromatographic conditions and MS parameters were optimized. The mouse brain tissue samples were homogenized with HCl solution (0.01 mol/L), protein precipitated with methanol and centrifugation. For the untargeted method, one sample was derivatized with butanol (D0)-HCl and another sample was derivatized with deuterated butanol (D9)-HCl, then combined together and analyzed with UHPLC-MS. Chromatographic peak area ratio for each amino acid was then used for differential analyses between two samples. Results showed good accuracy with standard spiked samples (83.4–113.0 %). For the targeted quantitative method, the sample supernatants were dried and residues were derivatized with butanol (D0)-HCl. Internal standards of amino acids derivatized with deuterated butanol (D9)-HCl were added before analyzed with UHPLC-MS/MS. The intra- and inter-day precisions were in the intervals of 0.5–8.1 % and 0.3–9.1 %. The LOD and the LOQ were ranged from 0.03 × 10−3 to 0.92 × 10−3 µg mL−1 and 0.08 × 10−3 to 3.08 × 10−3 µg mL−1, respectively. Spiked recoveries were from 96.8 % to 111.7 %. Both methods were applied to analyze amino acids in brain tissue of C57BL/6 mice treated and untreated with piperine and the result showed that the levels of glutamic acid, aspartic acid, histidine, asparagine, γ-aminobutyric acid, alanine, leucine and isoleucine significantly decreased in the piperine treated group comparing with the untreated group.

UHPLC-ESI-QE-Orbitrap-MS based metabolomics reveals the antioxidant mechanism of icaritin on mice with cerebral ischemic reperfusion.

Icaritin (ICT) has been previously demonstrated to display protective effects against cerebral ischemic reperfusion (I/R) by inhibiting oxidative stress, but the mechanism remains unclear. This study aimed to explore the mechanism from the perspective of metabolomics. A mice cerebral artery occlusion/reperfusion (MCAO/R) model was explored to mimic cerebral ischemic reperfusion and protective effect of ICT was assessed by neurologic deficit scoring, infarct volume and brain water content. Ultra-high-performance liquid chromatography electrospray ionization orbitrap tandem mass spectrometry (UHPLC-ESI-QE-Orbitrap-MS) based metabolomic was performed to explore potential biomarkers. Brain tissue metabolic profiles were analyzed and metabolic biomarkers were identified through multivariate data analysis. The protein levels of Nrf2, HO-1 and HQO1 were assayed by western blot. The release of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) were detected using corresponding assay kits. The results showed that after ICT treatment, the neurological deficit, cerebral infarction area, brain edema and the level of MDA in brain tissue of MCAO/R mice were significantly reduced. Meanwhile, ICT enhanced the activity of SOD, CAT and GSH-Px. Western blot results confirmed that ICT up-regulated the protein levels of antioxidant-related protein including Nrf2, HO-1 and NQO1. According to the metabolomic profiling of brain tissues, clear separations were observed among the Sham, Model and ICT groups. A total of 44 biomarkers were identified, and the identified biomarkers were mainly related to linoleic acid metabolism, arachidonic acid metabolism, alanine, aspartate and glutamate metabolism, arginine biosynthesis, arginine and proline metabolism, D-glutamine and D-glutamate metabolism, taurine and hypotaurine metabolism and purine metabolism, respectively. At the same time, the inhibitory effect of ICT on arachidonic acid and linoleic acid in brain tissue, as well as the promoting effect on taurine, GABA, NAAG, may be the key factors for the anti-neurooxidative function of mice after MCAO/R injury. Our results demonstrate that ICT has benefits for MCAO/R injury, which are partially related to the suppression of oxidative stress via stimulating the Nrf2 signaling and regulating the production of arachidonic acid, linoleic acid, taurine, GABA, NAAG in brain tissue.

Iron in Alzheimer's Disease: From Physiology to Disease Disabilities.

Reactive oxygen species (ROS) play a key role in the neurodegeneration processes. Increased oxidative stress damages lipids, proteins, and nucleic acids in brain tissue, and it is tied to the loss of biometal homeostasis. For this reason, attention has been focused on transition metals involved in several biochemical reactions producing ROS. Even though a bulk of evidence has uncovered the role of metals in the generation of the toxic pathways at the base of Alzheimer’s disease (AD), this matter has been sidelined by the advent of the Amyloid Cascade Hypothesis. However, the link between metals and AD has been investigated in the last two decades, focusing on their local accumulation in brain areas known to be critical for AD. Recent evidence revealed a relation between iron and AD, particularly in relation to its capacity to increase the risk of the disease through ferroptosis. In this review, we briefly summarize the major points characterizing the function of iron in our body and highlight why, even though it is essential for our life, we have to monitor its dysfunction, particularly if we want to control our risk of AD.

The relationship between the contents of 13 amino acids in brain tissues and the progression of NAFLD via C57BL/6 model mice

The relationship between the contents of 13 amino acids in brain tissues and the progression of NAFLD via C57BL/6 model mice

Neurotherapeutic effects of prodigiosin conjugated with silver-nanoparticles in rats exposed to cadmium chloride-induced neurotoxicity

Prodigiosin is a red pigment produced by Serratia marcescens strain. Bacterial prodigiosin and its synthetic derivatives are efficacious antioxidants and proapoptotic agents. This study illustrates a new approach for use of prodigiosin conjugated silver nanoparticles (PG-AgNP2) against cadmium chloride (CdCl2) induced neurotoxicity in rats. Rats were (ip) injected with Cd (6.5 mg/kg) for 7 days with or without PG-AgNP2 (3 mg/kg). The concentration of Cd, DA, NE, 5-HT, amino acids, NO, MDA, SOD, GSH, catalase, TNF-α, IL-6, Bax, Bcl2 and Caspase-3. The Cd-intoxicated group showed a significant increase in Cd concentration in brain tissue, in addition, to an increase in MDA and NO and a decrease in the content of neurotransmitters (DA, NE, and 5-HT), inhibitory amino acids, and level of all studied antioxidant enzymes. PG-AgNP2 treatment, significantly reduced Cd-induced brain tissue injury as indicated by increased antioxidant molecules, neurotransmitters (DA, NE, and 5-HT), and inhibitory amino acids accompanied by lower oxidative stress indices (MDA and NO) and excitatory amino acids in brain tissue. PG-AgNP2 decreased inflammatory mediators including pro-inflammatory cytokines and prevented the development of apoptosis in the brain tissue. Our findings suggest that PG-AgNP2 can act as a therapeutic agent against neuronal impairments associated with Cd exposure.

Histogenous Hypoxia and Acid Retention in Schizophrenia: Changes in Venous Blood Gas Analysis and SOD in Acute and Stable Schizophrenia Patients.

Background: Oxidative stress may play an important role in the pathogenesis of schizophrenia (SCH), and there is considerable indirect evidence that hypoxia is closely related to SCH, but direct evidence of hypoxia in SCH has never been found.Methods:In this study, superoxide dismutase (SOD), venous blood gas, and Positive and Negative Syndrome Scale (PANSS) were examined in 40 SCH patients and compared with those of 40 healthy controls. The patients were treated with combination of atypical antipsychotics and Ditan Huayu Lishen decoction (a Chinese medicine decoction) and examined in the acute and stable period, respectively. Comparisons of indicators between two groups were performed using an independent-samples t-test, comparison of indicators between the acute and stable periods in the SCH group was performed using paired-samples t-test. Pearson correlation and multiple linear regression analyses were performed to investigate the relationships between the effect indicators.Results: Higher venous pH, PvO2, and fasting blood glucose levels and lower SOD, lactic acid, and PvCO2 levels were found in SCH patients compared with the control group; SOD was negatively correlated with the general psychopathology subscale score (PANSS-G), and PvO2 levels were closely related to venous pH in SCH and related to PvCO2 in the control group. It was also found that SOD activity showed no significant difference in acute and stable period, whereas PvO2 showed a downward trend, and venous pH was decreased significantly after treatment. Both the venous pH and PvO2 were higher in patients with SCH than that in healthy controls.Conclusion: It suggests that histogenous hypoxia and acid retention exist in relation to SCH, and there is an improvement of acid retention and a downward trend in histogenous hypoxia after combination treatment. Venous pH, PvO2, and PvCO2 are trait variables, but not state variables of SCH. The theory of histogenous hypoxia and acid retention can well explain the decrease in pH value and the increase in lactic acid in brain tissue of patients with SCH. Histogenous hypoxia and acid retention closely related to glucose metabolism. So they may play an important role in pathophysiology for SCH.

Ratiometric Detection of Hypochlorous Acid in Brain Tissues of Neuroinflammation and Maternal Immune Activation Models with a Deep-Red/Near-Infrared Emitting Probe.

Reactive oxygen species (ROS) produced by an inflammatory response in the brain are associated with various neurological disorders. To investigate ROS-associated neuroinflammatory diseases, fluorescent probes with practicality are in demand. We have investigated hypochlorous acid, an important ROS, in the brain tissues of neuroinflammation and maternal immune activation (MIA) model mice, using a new fluorescent probe. The probe has outstanding features over many known probes, such as providing two bright ratio signals in cells and tissues in deep-red/near-infrared wavelength regions with a large spectral separation, in addition to being strongly fluorescent, photo- and chemo-stable, highly selective and sensitive, fast responding, and biocompatible. We have found that the level of hypochlorous acid in the brain tissue of a neuroinflammatory mouse model was higher (2.7-4.0-fold) compared with that in normal brain tissue. Furthermore, the level of hypochlorous acid in the brain tissue of a MIA mouse model was higher (1.2-1.3-fold) compared with that in the normal brain tissue. The "robust" probe provides a practical tool for studying ROS-associated neurological disorders.

Natural Products with Analgesic Effect from Herbs and Nutraceuticals Used in Traditional Chinese Medicines.

Pain is one of the most common clinical symptoms . This review aims to describe research on herbs and their active ingredients in treating pain and provide a valuable reference for the development and utilization of analgesic traditional Chinese medicine (TCM). The literature search was performed from 1995 to October 2016, covering the relevant studies that concern the treatment of pain with TCM. Active ingredients extracted from TCM with analgesic activity are summarized and classified into six categories, including polysaccharides, saponins, alkaloids, flavonoids, terpenoids, and other constituents. There are two pathways constituting the analgesic mechanisms of TCM: through the central nervous system and the peripheral nervous system. The former pathway includes increasing the content of endogenous analgesic substances like opiate peptide, cutting down the second messenger of neurotransmitter like nitric oxide (NO), reducing the content of prostaglandin E2 (PGE2) in brain tissues, blocking the central calcium channel, reducing excitatory amino acids in brain tissues, inhibiting their receptors and raising the content of the central 5-hydroxytryptamine (5-HT). The latter one usually involves the decrease in the secretion of peripheral algogenic substances, the induction of pain-sensitive substances, the accumulation of a local algogenic substance, the increase in the release of peripheral endogenous analgesia materials and the regulation of c-Fos gene (immediate early gene).

Application of Butylamine as a Conjugative Reagent to On-Column Derivatization for the Determination of Antioxidant Amino Acids in Brain Tissue, Plasma, and Urine Samples.

(1) Antioxidants are involved in body protection mechanisms against reactive oxygen species. Amino acids such as glutathione (GSH) and N-acetylcysteine (NAC) are known to be involved in providing protection against oxidative lethality. A quick and simple method for the determination of NAC and GSH in various biological matrices such as urine, plasma, and homogenates of brain tissues has been developed and described in this work. (2) The assay is based on reversed phase high performance liquid chromatography with spectrofluorimetric detection and on-column derivatization. Butylamine and o-phthaldialdehyde have been used as derivatization reagents. Since o-phthaldialdehyde constitutes a part of the mobile phase, the derivatization reaction and chromatographic separation occur simultaneously. (3) Linearity in the detector response for NAC in human urine was observed in the range of 5–200 nmol mL−1, and NAC and GSH in the brain tissue homogenates were observed in the range of 0.5–5 nmol mL−1 and 0.5–15 nmol mL−1, respectively. Human plasma linearity ranges covered 0.25–5.00 nmol mL−1 and 0.5–15 nmol mL−1 for NAC and GSH, respectively. The LODs for NAC and GSH were 0.01 and 0.02 nmol mL−1 while the LOQs were 0.02 and 0.05 nmol mL−1, respectively. The usefulness of the proposed method was proven through its application to real samples.

CHANGES IN THE CHEMICAL COMPOSITION OF BLOOD AND BRAIN OF RATS UNDER THE CONDITIONS OF MODELING OF THE MYELOABLATION REGIMEN OF CYCLOPHOSPHAMIDE ADMINISTRATION

When modeling myeloablation cytostatic chemotherapy with cyclophosphamide in rats fulminant hyperammonemia was observed accompanied by an increase in the content of ammonia and glutamine, a decrease in the content of pyruvic and lactic acids in brain tissue. A positive correlation between the indicators of azotemia and the content of ammonia and glutamine in brain tissue was established. In loading test with ammonium acetate changes in the chemical composition of blood and brain tissue were more pronounced. The data obtained indicate the intensification of the intake of gastrointestinal ammonia into the brain from the blood, which leads to the depletion of the tissue pool of pyruvate with the introduction of cyclophosphane in doses used for myeloablation. Such changes create the conditions for disruption of energy supply of neurological functions during myeloablative cytotoxic chemotherapy using cyclophosphamide.

Decreased rates of cerebral protein synthesis measured invivo in a mouse model of Tuberous Sclerosis Complex: unexpected consequences of reduced tuberin.

Tuberous sclerosis complex (TSC) is an autosomal dominant neurogenetic disorder affecting about 1 in 6000 people and is caused by mutations in either TSC1 or TSC2. This disorder is characterized by increased activity of mammalian target of rapamycin complex 1 (mTORC1), which is involved in regulating ribosomal biogenesis and translation initiation. We measured the effects of Tsc2 haploinsufficiency (Tsc2+/- ) in 3-month-old male mice on regional rates of cerebral protein synthesis (rCPS) by means of the invivo L-[1-14 C]leucine method. This quantitative autoradiographic method includes an estimate of the integrated specific activity of the tracer amino acid in brain tissue. The estimate accounts for recycling of unlabeled amino acids from tissue protein breakdown by means of a factor (λ) that was determined in control and Tsc2+/- mice. The value of λ was higher in Tsc2+/- mice, indicating that a greater fraction of leucine in the tissue precursor pool for protein synthesis is derived from the plasma compared to controls, consistent with reduced rates of protein degradation. We determined rCPS in freely moving, awake male Tsc2+/- and control mice, and we used the determined values of λ in the calculation of rCPS. Unexpectedly, we found that rCPS were significantly decreased in 16 of the 17 brain regions analyzed in Tsc2+/- mice compared to controls. Our results indicate a complex role of mTORC1 in the regulation of cerebral protein synthesis that has not been previously recognized.

Inhibition of β-oxidation is not a valid therapeutic tool for reducing oxidative stress in conditions of neurodegeneration

According to recent reports, systemic treatment of rats with methylpalmoxirate (carnitine palmitoyltransferase-1 inhibitor) decreased peroxidation of polyunsaturated fatty acids in brain tissue. This was taken as evidence of mitochondrial β-oxidation in brain, thereby contradicting long-standing paradigms of cerebral metabolism, which claim that β-oxidation of activated fatty acids has minor importance for brain energy homeostasis. We addressed this controversy. Our experiments are the first direct experimental analysis of this question. We fueled isolated brain mitochondria or rat brain astrocytes with octanoic acid, but octanoic acid does not enhance formation of reactive oxygen species, neither in isolated brain mitochondria nor in astrocytes, even at limited hydrogen delivery to mitochondria. Thus, octanoic acid or l-octanoylcarnitine does not stimulate H2O2 release from brain mitochondria fueled with malate, in contrast to liver mitochondria (2.25-fold rise). This does obviously not support the possible occurrence of β-oxidation of the fatty acid octanoate in the brain. We conclude that a proposed inhibition of β-oxidation does not seem to be a helpful strategy for therapies aiming at lowering oxidative stress in cerebral tissue. This question is important, since oxidative stress is the cause of neurodegeneration in numerous neurodegenerative or inflammatory disease situations.

Efficient Docosahexaenoic Acid Uptake by the Brain from a Structured Phospholipid.

Docosahexaenoic acid (DHA) is the main essential omega-3 fatty acid in brain tissues required for normal brain development and function. An alteration of brain DHA in neurodegenerative diseases such as Alzheimer's and Parkinson's is observed. Targeted intake of DHA to the brain could compensate for these deficiencies. Blood DHA is transported across the blood-brain barrier more efficiently when esterified at the sn-2 position of lyso-phosphatidylcholine. We used a structured phosphatidylcholine to mimic 2-docosahexaenoyl-lysoPC (lysoPC-DHA), named AceDoPC (1-acetyl,2-docosahexaenoyl-glycerophosphocholine), that may be considered as a stabilized form of the physiological lysoPC-DHA and that is neuroprotective in experimental ischemic stroke. The aim of the present study was to investigate whether AceDoPC is a relevant delivery form of DHA to the brain in comparison with other forms of the fatty acid. By combining in vitro and in vivo experiments, our findings report for the first time that AceDoPC is a privileged and specific carrier of DHA to the brain, when compared with DHA-containing PC and non-esterified DHA. We also show that AceDoPC was hydrolyzed, in part, into lysoPC-DHA. Ex vivo autoradiography of rat brain reveals that DHA from AceDoPC was localized in specific brain regions playing key roles in memory, thoughts, and cognitive functions. Finally, using molecular modeling approaches, we demonstrate that electrostatic and lipophilic potentials are distributed very similarly at the surfaces of AceDoPC and lysoPC-DHA. Our findings identify AceDoPC as an efficient way to specifically target DHA to the brain, which would allow potential preventive and therapeutic approaches for neurological diseases.

Methylenetetrahydrofolate reductase deficiency alters levels of glutamate and γ-aminobutyric acid in brain tissue

Methylenetetrahydrofolate reductase (MTHFR) is an enzyme key regulator in folate metabolism. Deficiencies in MTHFR result in increased levels of homocysteine, which leads to reduced levels of S-adenosylmethionine (SAM). In the brain, SAM donates methyl groups to catechol-O-methyltransferase (COMT), which is involved in neurotransmitter analysis. Using the MTHFR-deficient mouse model the purpose of this study was to investigate levels of monoamine neurotransmitters and amino acid levels in brain tissue. MTHFR deficiency affected levels of both glutamate and γ-aminobutyric acid in within the cerebellum and hippocampus. Mthfr−/− mice had reduced levels of glutamate in the amygdala and γ-aminobutyric acid in the thalamus. The excitatory mechanisms of homocysteine through activation of the N-methyl-d-aspartate receptor in brain tissue might alter levels of glutamate and γ-aminobutyric acid.

Determination of endogenous amino Acids in brain tissues after cerebral ischemia by RRLC-QQQ

To establish a method to determine underivatized endogenous amino acids in brain tissues after cerebral ischemia based on RRLC-QQQ. Diamonsil chromatographic column C18 (4.6 mm x 250 mm, 5 microm) was adopted to determine 12 amino acids in 15 min, with acetonitrile-0.1% formic acid for gradient elution. The flow rate was set at 0.5 mL x min(-1). With ESI as the ion source, positive ion scanning mode was adopted for multi-reaction monitoring. Each amino acid standard curve (AAs) showed good linear relationship within the detection range (r > 0.996), with the limit of detection of less than 11%, the limit of quantitation of less than 3.09 microg x L(-1). The RSD of intra- and inter-day precisions at high, middle and low concentrations were less than 11%. The determination results of actual samples showed that compared with the levels of AAs of the sham operation group, all of the remaining amino acids apart from N-acetyl-aspartate increased in brain tissues. Some amino acids showed significant changes in a time-dependent manner after the operation. The method is so simple, rapid and sensitive that it can be used for finding biological metabolite markers of cerebral ischemia, and exploring cerebral ischemia molecular mechanisms and synergistic mechanism of combined administration of multi-component traditional Chinese medicines.

Decreased levels of free d-aspartic acid in the forebrain of serine racemase (Srr) knock-out mice

d-Serine, an endogenous co-agonist of the N-methyl-d-aspartate (NMDA) receptor is synthesized from l-serine by serine racemase (SRR). A previous study of Srr knockout (Srr-KO) mice showed that levels of d-serine in forebrain regions, such as frontal cortex, hippocampus, and striatum, but not cerebellum, of mutant mice are significantly lower than those of wild-type (WT) mice, suggesting that SRR is responsible for d-serine production in the forebrain. In this study, we attempted to determine whether SRR affects the level of other amino acids in brain tissue. We found that tissue levels of d-aspartic acid in the forebrains (frontal cortex, hippocampus and striatum) of Srr-KO mice were significantly lower than in WT mice, whereas levels of d-aspartic acid in the cerebellum were not altered. Levels of d-alanine, l-alanine, l-aspartic acid, taurine, asparagine, arginine, threonine, γ-amino butyric acid (GABA) and methionine, remained the same in frontal cortex, hippocampus, striatum and cerebellum of WT and mutant mice. Furthermore, no differences in d-aspartate oxidase (DDO) activity were detected in the forebrains of WT and Srr-KO mice. These results suggest that SRR and/or d-serine may be involved in the production of d-aspartic acid in mouse forebrains, although further detailed studies will be necessary to confirm this finding.