Analysis of lipid raft molecules in the living brain slices.

Science.gov (United States)

Kotani, Norihiro; Nakano, Takanari; Ida, Yui; Ito, Rina; Hashizume, Miki; Yamaguchi, Arisa; Seo, Makoto; Araki, Tomoyuki; Hojo, Yasushi; Honke, Koichi; Murakoshi, Takayuki

2017-08-24

Neuronal plasma membrane has been thought to retain a lot of lipid raft components which play important roles in the neural function. Although the biochemical analyses of lipid raft using brain tissues have been extensively carried out in the past 20 years, many of their experimental conditions do not coincide with those of standard neuroscience researches such as neurophysiology and neuropharmacology. Hence, the physiological methods for lipid raft analysis that can be compatible with general neuroscience have been required. Herein, we developed a system to physiologically analyze ganglioside GM1-enriched lipid rafts in brain tissues using the "Enzyme-Mediated Activation of Radical Sources (EMARS)" method that we reported (Kotani N. et al. Proc. Natl. Acad. Sci. U S A 105, 7405-7409 (2008)). The EMARS method was applied to acute brain slices prepared from mouse brains in aCSF solution using the EMARS probe, HRP-conjugated cholera toxin subunit B, which recognizes ganglioside GM1. The membrane molecules present in the GM1-enriched lipid rafts were then labeled with fluorescein under the physiological condition. The fluorescein-tagged lipid raft molecules called "EMARS products" distributed differentially among various parts of the brain. On the other hand, appreciable differences were not detected among segments along the longitudinal axis of the hippocampus. We further developed a device to label the lipid raft molecules in acute hippocampal slices under two different physiological conditions to detect dynamics of the lipid raft molecules during neural excitation. Using this device, several cell membrane molecules including Thy1, known as a lipid raft resident molecule in neurons, were confirmed by the EMARS method in living hippocampal slices. Copyright © 2017 Elsevier Ltd. All rights reserved.

Specific binding of atrial natriuretic factor in brain microvessels

International Nuclear Information System (INIS)

Chabrier, P.E.; Roubert, P.; Braquet, P.

1987-01-01

Cerebral capillaries constitute the blood-brain barrier. Studies of specific receptors (neurotransmitters or hormones) located on this structure can be performed by means of radioligand-binding techniques on isolated brain microvessels. The authors examined on pure bovine cerebral microvessel preparations the binding of atrial natriuretic factor (ANF), using 125 I-labeled ANF. Saturation and competition experiments demonstrated the presence of a single class of ANF-binding sites with high affinity and with a binding capacity of 58 fmol/mg of protein. The binding of 125 I-labeled ANF to brain microvessels is specific, reversible, and time dependent, as is shown by association-dissociation experiments. The demonstration of specific ANF-binding sites on brain microvessels supposes a physiological role of ANF on brain microvasculature. The coexistence of ANF and angiotensin II receptors on this cerebrovascular tissue suggests that the two circulating peptides may act as mutual antagonists in the regulation of brain microcirculation and/or blood-brain barrier function

Interplay of electrostatics and lipid packing determines the binding of charged polymer coated nanoparticles to model membranes.

Science.gov (United States)

Biswas, Nupur; Bhattacharya, Rupak; Saha, Arindam; Jana, Nikhil R; Basu, Jaydeep K

2015-10-07

Understanding of nanoparticle-membrane interactions is useful for various applications of nanoparticles like drug delivery and imaging. Here we report on the studies of interaction between hydrophilic charged polymer coated semiconductor quantum dot nanoparticles with model lipid membranes. Atomic force microscopy and X-ray reflectivity measurements suggest that cationic nanoparticles bind and penetrate bilayers of zwitterionic lipids. Penetration and binding depend on the extent of lipid packing and result in the disruption of the lipid bilayer accompanied by enhanced lipid diffusion. On the other hand, anionic nanoparticles show minimal membrane binding although, curiously, their interaction leads to reduction in lipid diffusivity. It is suggested that the enhanced binding of cationic QDs at higher lipid packing can be understood in terms of the effective surface potential of the bilayers which is tunable through membrane lipid packing. Our results bring forth the subtle interplay of membrane lipid packing and electrostatics which determine nanoparticle binding and penetration of model membranes with further implications for real cell membranes.

PICK1 regulates the trafficking of ASIC1a and acidotoxicity in a BAR domain lipid binding-dependent manner

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Jin Wenying

2010-12-01

Full Text Available Abstract Background Acid-sensing ion channel 1a (ASIC1a is the major ASIC subunit determining acid-activated currents in brain neurons. Recent studies show that ASIC1a play critical roles in acid-induced cell toxicity. While these studies raise the importance of ASIC1a in diseases, mechanisms for ASIC1a trafficking are not well understood. Interestingly, ASIC1a interacts with PICK1 (protein interacting with C-kinase 1, an intracellular protein that regulates trafficking of several membrane proteins. However, whether PICK1 regulates ASIC1a surface expression remains unknown. Results Here, we show that PICK1 overexpression increases ASIC1a surface level. A BAR domain mutant of PICK1, which impairs its lipid binding capability, blocks this increase. Lipid binding of PICK1 is also required for PICK1-induced clustering of ASIC1a. Consistent with the effect on ASIC1a surface levels, PICK1 increases ASIC1a-mediated acidotoxicity and this effect requires both the PDZ and BAR domains of PICK1. Conclusions Taken together, our results indicate that PICK1 regulates trafficking and function of ASIC1a in a lipid binding-dependent manner.

Effect of cadmium on lipid metabolism of brain. In vivo incorporation of labelled acetate into lipids

Energy Technology Data Exchange (ETDEWEB)

Gulati, S; Gill, K D; Nath, R

1987-01-01

The effect of early postnatal cadmium exposure on the in vivo incorporation of (1-/sup 14/C) sodium acetate into various lipid classes of the weanling rat brain was studied. A stimulated incorporation of the label was observed in total lipids, phospholipids, cholesterol, cerebrosides and sulphatides of the brain of Cd-exposed animals compared to controls.

Binding of Serotonin to Lipid Membranes

DEFF Research Database (Denmark)

Peters, Günther H.J.; Wang, Chunhua; Cruys-Bagger, Nicolaj

2013-01-01

Serotonin (5-hydroxytryptamine, 5-HT) is a prevalent neurotransmitter throughout the animal kingdom. It exerts its effect through the specific binding to the serotonin receptor, but recent research has suggested that neural transmission may also be affected by its nonspecific interactions...... with the lipid matrix of the synaptic membrane. However, membrane–5-HT interactions remain controversial and superficially investigated. Fundamental knowledge of this interaction appears vital in discussions of putative roles of 5-HT, and we have addressed this by thermodynamic measurements and molecular...... dynamics (MD) simulations. 5-HT was found to interact strongly with lipid bilayers (partitioning coefficient ∼1200 in mole fraction units), and this is highly unusual for a hydrophilic solute like 5-HT which has a bulk, oil–water partitioning coefficient well below unity. It follows that membrane affinity...

Air pollutant sulfur dioxide-induced alterations on the levels of lipids, lipid peroxidation and lipase activity in various regions of the rat brain

Energy Technology Data Exchange (ETDEWEB)

Haider, S S; Hasan, M; Khan, N H

1982-07-01

The exposure of rats to SO/sub 2/ (10 p.p.m.) for one hour daily for 30 days caused depletion of total lipids in all brain areas. The contents of phospholipid were elevated in cerebellum and brain stem, but were depleted in cerebral hemisphere. Cholesterol levels showed an increase in various brain regions. On the other hand, gangliosides were increased in cerebellum and brain stem, but were decreased in cerebral hemisphere. Interestingly, cholesterol/phospholipid ratio was increased in different regions of the brain. Lipase activity was elevated in cerebral hemisphere. Lipid peroxidation showed marked increment in whole brain and in all the brain areas studied. The results suggest that SO/sub 2/-exposure induces degradation of lipids. Interestingly, the lipid contents are affected differentially in the various parts of the brain.

Brain Glucose Metabolism Controls Hepatic Glucose and Lipid Production

OpenAIRE

Lam, Tony K.T.

2007-01-01

Brain glucose-sensing mechanisms are implicated in the regulation of feeding behavior and hypoglycemic-induced hormonal counter-regulation. This commentary discusses recent findings indicating that the brain senses glucose to regulate both hepatic glucose and lipid production.

Mu opioid receptor binding sites in human brain

International Nuclear Information System (INIS)

Pilapil, C.; Welner, S.; Magnan, J.; Zamir, N.; Quirion, R.

1986-01-01

Our experiments focused on the examination of the distribution of mu opioid receptor binding sites in normal human brain using the highly selective ligand [ 3 H]DAGO, in both membrane binding assay and in vitro receptor autoradiography. Mu opioid binding sites are very discretely distributed in human brain with high densities of sites found in the posterior amygdala, caudate, putamen, hypothalamus and certain cortical areas. Moreover the autoradiographic distribution of [ 3 H]DAGO binding sites clearly reveals the discrete lamination (layers I and III-IV) of mu sites in cortical areas

A novel lipid transfer protein from the pea Pisum sativum: isolation, recombinant expression, solution structure, antifungal activity, lipid binding, and allergenic properties.

Science.gov (United States)

Bogdanov, Ivan V; Shenkarev, Zakhar O; Finkina, Ekaterina I; Melnikova, Daria N; Rumynskiy, Eugene I; Arseniev, Alexander S; Ovchinnikova, Tatiana V

2016-04-30

Plant lipid transfer proteins (LTPs) assemble a family of small (7-9 kDa) ubiquitous cationic proteins with an ability to bind and transport lipids as well as participate in various physiological processes including defense against phytopathogens. They also form one of the most clinically relevant classes of plant allergens. Nothing is known to date about correlation between lipid-binding and IgE-binding properties of LTPs. The garden pea Pisum sativum is widely consumed crop and important allergenic specie of the legume family. This work is aimed at isolation of a novel LTP from pea seeds and characterization of its structural, functional, and allergenic properties. Three novel lipid transfer proteins, designated as Ps-LTP1-3, were found in the garden pea Pisum sativum, their cDNA sequences were determined, and mRNA expression levels of all the three proteins were measured at different pea organs. Ps-LTP1 was isolated for the first time from the pea seeds, and its complete amino acid sequence was determined. The protein exhibits antifungal activity and is a membrane-active compound that causes a leakage from artificial liposomes. The protein binds various lipids including bioactive jasmonic acid. Spatial structure of the recombinant uniformly (13)C,(15)N-labelled Ps-LTP1 was solved by heteronuclear NMR spectroscopy. In solution the unliganded protein represents the mixture of two conformers (relative populations ~ 85:15) which are interconnected by exchange process with characteristic time ~ 100 ms. Hydrophobic residues of major conformer form a relatively large internal tunnel-like lipid-binding cavity (van der Waals volume comes up to ~1000 Å(3)). The minor conformer probably corresponds to the protein with the partially collapsed internal cavity. For the first time conformational heterogeneity in solution was shown for an unliganded plant lipid transfer protein. Heat denaturation profile and simulated gastrointestinal digestion assay showed that Ps

Relation between plasma and brain lipids

DEFF Research Database (Denmark)

Wellington, Cheryl L; Frikke-Schmidt, Ruth

2016-01-01

: Plasma levels of traditional lipids and lipoproteins are not consistently associated with risk of dementia even though low plasma levels of apolipoprotein E, through unknown mechanisms, robustly predict future dementia. Experimental evidence suggests neuroprotective roles of several brain...... and cerebrospinal fluid apolipoproteins. Whether plasma levels of apolipoprotein E, or any other apolipoprotein with possible central nervous system and/or blood-brain barrier functions (apolipoproteins J, A-I, A-II, A-IV, D, C-I, and C-III) may become accessible biomarker components that improve risk prediction...

Lipid binding to cytoglobin leads to a change in haem co-ordination: a role for cytoglobin in lipid signalling of oxidative stress.

Science.gov (United States)

Reeder, Brandon J; Svistunenko, Dimitri A; Wilson, Michael T

2011-03-15

Cytoglobin is a recently discovered hexa-co-ordinate haemoglobin that does not appear to function as a classical oxygen-binding protein. Its function is unknown and studies on the effects of changes in its expression have not decisively determined its role within the cell. In the present paper, we report that the protein is transformed from hexa-co-ordinate to penta-co-ordinate on binding a lipid molecule. This transformation occurs with the ferric oxidation state of the protein, but not the ferrous state, indicating that this process only occurs under an oxidative environment and may thus be related to redox-linked cell signalling mechanisms. Oleate binds to the protein in a 1:1 stoichiometry and with high affinity (K(d)=0.7 μM); however, stopped-flow kinetic measurements yield a K(d) value of 110 μM. The discrepancy between these K(d) values may be rationalized by recognizing that cytoglobin is a disulfide-linked dimer and invoking co-operativity in oleate binding. The lipid-induced transformation of cytoglobin from hexa-co-ordinate to penta-co-ordinate does not occur with similar hexa-co-ordinate haemoglobins such as neuroglobin, and therefore appears to be a unique property of cytoglobin among the haemoglobin superfamily. The lipid-derived transformation may explain why cytoglobin has enhanced peroxidatic activity, converting lipids into various oxidized products, a property virtually absent from neuroglobin and much decreased in myoglobin. We propose that the binding of ferric cytoglobin to lipids and their subsequent transformation may be integral to the physiological function of cytoglobin, generating cell signalling lipid molecules under an oxidative environment.

[3H]cytisine binding to nicotinic cholinergic receptors in brain

International Nuclear Information System (INIS)

Pabreza, L.A.; Dhawan, S.; Kellar, K.J.

1991-01-01

Cytisine, a ganglionic agonist, competes with high affinity for brain nicotinic cholinergic receptors labeled by any of several nicotinic 3 H-agonist ligands. Here we have examined the binding of [ 3 H]cytisine in rat brain homogenates. [ 3 H]Cytisine binds with high affinity (Kd less than 1 nM), and specific binding represented 60-90% of total binding at all concentrations examined up to 15 nM. The nicotinic cholinergic agonists nicotine, acetylcholine, and carbachol compete with high affinity for [ 3 H]cytisine binding sites, whereas among nicotinic receptor antagonists only dihydro-beta-erythroidine competes with high affinity (in the nanomolar range). Comparison of binding in several brain regions showed that [ 3 H]cytisine binding is higher in the thalamus, striatum, and cortex than in the hippocampus, cerebellum, or hypothalamus. The pharmacology and brain regional distribution of [ 3 H]cytisine binding sites are those predicted for neuronal nicotinic receptor agonist recognition sites. The high affinity and low nonspecific binding of [ 3 H]cytisine should make it a very useful ligand for studying neuronal nicotinic receptors

Long-Term Effect of Docosahexaenoic Acid Feeding on Lipid Composition and Brain Fatty Acid-Binding Protein Expression in Rats

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Marwa E. Elsherbiny

2015-10-01

Full Text Available Arachidonic (AA and docosahexaenoic acid (DHA brain accretion is essential for brain development. The impact of DHA-rich maternal diets on offspring brain fatty acid composition has previously been studied up to the weanling stage; however, there has been no follow-up at later stages. Here, we examine the impact of DHA-rich maternal and weaning diets on brain fatty acid composition at weaning and three weeks post-weaning. We report that DHA supplementation during lactation maintains high DHA levels in the brains of pups even when they are fed a DHA-deficient diet for three weeks after weaning. We show that boosting dietary DHA levels for three weeks after weaning compensates for a maternal DHA-deficient diet during lactation. Finally, our data indicate that brain fatty acid binding protein (FABP7, a marker of neural stem cells, is down-regulated in the brains of six-week pups with a high DHA:AA ratio. We propose that elevated levels of DHA in developing brain accelerate brain maturation relative to DHA-deficient brains.

Lipid-regulated sterol transfer between closely apposed membranes by oxysterol-binding protein homologues.

Science.gov (United States)

Schulz, Timothy A; Choi, Mal-Gi; Raychaudhuri, Sumana; Mears, Jason A; Ghirlando, Rodolfo; Hinshaw, Jenny E; Prinz, William A

2009-12-14

Sterols are transferred between cellular membranes by vesicular and poorly understood nonvesicular pathways. Oxysterol-binding protein-related proteins (ORPs) have been implicated in sterol sensing and nonvesicular transport. In this study, we show that yeast ORPs use a novel mechanism that allows regulated sterol transfer between closely apposed membranes, such as organelle contact sites. We find that the core lipid-binding domain found in all ORPs can simultaneously bind two membranes. Using Osh4p/Kes1p as a representative ORP, we show that ORPs have at least two membrane-binding surfaces; one near the mouth of the sterol-binding pocket and a distal site that can bind a second membrane. The distal site is required for the protein to function in cells and, remarkably, regulates the rate at which Osh4p extracts and delivers sterols in a phosphoinositide-dependent manner. Together, these findings suggest a new model of how ORPs could sense and regulate the lipid composition of adjacent membranes.

Structure and mechanism of calmodulin binding to a signaling sphingolipid reveal new aspects of lipid-protein interactions

Science.gov (United States)

Kovacs, Erika; Harmat, Veronika; Tóth, Judit; Vértessy, Beáta G.; Módos, Károly; Kardos, József; Liliom, Károly

2010-01-01

Lipid-protein interactions are rarely characterized at a structural molecular level due to technical difficulties; however, the biological significance of understanding the mechanism of these interactions is outstanding. In this report, we provide mechanistic insight into the inhibitory complex formation of the lipid mediator sphingosylphosphorylcholine with calmodulin, the most central and ubiquitous regulator protein in calcium signaling. We applied crystallographic, thermodynamic, kinetic, and spectroscopic approaches using purified bovine calmodulin and bovine cerebral microsomal fraction to arrive at our conclusions. Here we present 1) a 1.6-Å resolution crystal structure of their complex, in which the sphingolipid occupies the conventional hydrophobic binding site on calmodulin; 2) a peculiar stoichiometry-dependent binding process: at low or high protein-to-lipid ratio calmodulin binds lipid micelles or a few lipid molecules in a compact globular conformation, respectively, and 3) evidence that the sphingolipid displaces calmodulin from its targets on cerebral microsomes. We have ascertained the specificity of the interaction using structurally related lipids as controls. Our observations reveal the structural basis of selective calmodulin inhibition by the sphingolipid. On the basis of the crystallographic and biophysical characterization of the calmodulin–sphingosylphosphorylcholine interaction, we propose a novel lipid-protein binding model, which might be applicable to other interactions as well.—Kovacs, E., Harmat, V., Tóth, J., Vértessy, B. G., Módos, K., Kardos, J., Liliom, K. Structure and mechanism of calmodulin binding to a signaling sphingolipid reveal new aspects of lipid-protein interactions. PMID:20522785

Inhibition of fatty acid binding proteins elevates brain anandamide levels and produces analgesia.

Directory of Open Access Journals (Sweden)

Martin Kaczocha

Full Text Available The endocannabinoid anandamide (AEA is an antinociceptive lipid that is inactivated through cellular uptake and subsequent catabolism by fatty acid amide hydrolase (FAAH. Fatty acid binding proteins (FABPs are intracellular carriers that deliver AEA and related N-acylethanolamines (NAEs to FAAH for hydrolysis. The mammalian brain expresses three FABP subtypes: FABP3, FABP5, and FABP7. Recent work from our group has revealed that pharmacological inhibition of FABPs reduces inflammatory pain in mice. The goal of the current work was to explore the effects of FABP inhibition upon nociception in diverse models of pain. We developed inhibitors with differential affinities for FABPs to elucidate the subtype(s that contributes to the antinociceptive effects of FABP inhibitors. Inhibition of FABPs reduced nociception associated with inflammatory, visceral, and neuropathic pain. The antinociceptive effects of FABP inhibitors mirrored their affinities for FABP5, while binding to FABP3 and FABP7 was not a predictor of in vivo efficacy. The antinociceptive effects of FABP inhibitors were mediated by cannabinoid receptor 1 (CB1 and peroxisome proliferator-activated receptor alpha (PPARα and FABP inhibition elevated brain levels of AEA, providing the first direct evidence that FABPs regulate brain endocannabinoid tone. These results highlight FABPs as novel targets for the development of analgesic and anti-inflammatory therapeutics.

Structural Determinants of Specific Lipid Binding to Potassium Channels

NARCIS (Netherlands)

Weingarth, M.H.|info:eu-repo/dai/nl/330985655; Prokofyev, A.; van der Cruijsen, E.A.W.|info:eu-repo/dai/nl/330826743; Nand, D.|info:eu-repo/dai/nl/337731403; Bonvin, A.M.J.J.|info:eu-repo/dai/nl/113691238; Pongs, O.; Baldus, M.|info:eu-repo/dai/nl/314410864

2013-01-01

We have investigated specific lipid binding to the pore domain of potassium channels KcsA and chimeric KcsAKv1.3 on the structural and functional level using extensive coarse-grained and atomistic molecular dynamics simulations, solid-state NMR, and single channel measurements. We show that, while

Tailoring Lipid and Polymeric Nanoparticles as siRNA Carriers towards the Blood-Brain Barrier - from Targeting to Safe Administration.

Science.gov (United States)

Gomes, Maria João; Fernandes, Carlos; Martins, Susana; Borges, Fernanda; Sarmento, Bruno

2017-03-01

Blood-brain barrier is a tightly packed layer of endothelial cells surrounding the brain that acts as the main obstacle for drugs enter the central nervous system (CNS), due to its unique features, as tight junctions and drug efflux systems. Therefore, since the incidence of CNS disorders is increasing worldwide, medical therapeutics need to be improved. Consequently, aiming to surpass blood-brain barrier and overcome CNS disabilities, silencing P-glycoprotein as a drug efflux transporter at brain endothelial cells through siRNA is considered a promising approach. For siRNA enzymatic protection and efficient delivery to its target, two different nanoparticles platforms, solid lipid (SLN) and poly-lactic-co-glycolic (PLGA) nanoparticles were used in this study. Polymeric PLGA nanoparticles were around 115 nm in size and had 50 % of siRNA association efficiency, while SLN presented 150 nm and association efficiency close to 52 %. Their surface was functionalized with a peptide-binding transferrin receptor, in a site-oriented manner confirmed by NMR, and their targeting ability against human brain endothelial cells was successfully demonstrated by fluorescence microscopy and flow cytometry. The interaction of modified nanoparticles with brain endothelial cells increased 3-fold compared to non-modified lipid nanoparticles, and 4-fold compared to non-modified PLGA nanoparticles, respectively. These nanosystems, which were also demonstrated to be safe for human brain endothelial cells, without significant cytotoxicity, bring a new hopeful breath to the future of brain diseases therapies.

Brain-targeted solid lipid nanoparticles containing riluzole: preparation, characterization and biodistribution.

Science.gov (United States)

Bondì, Maria Luisa; Craparo, Emanuela Fabiola; Giammona, Gaetano; Drago, Filippo

2010-01-01

Developments within nanomedicine have revealed a great potential for drug delivery to the brain. In this study nanoparticulate systems as drug carriers for riluzole, with sufficiently high loading capacity and small particle size, were prepared to a reach therapeutic drug level in the brain. Solid lipid nanoparticles containing riluzole have great potential as drug-delivery systems for amyotrophic lateral sclerosis and were produced by using the warm oil-in-water microemulsion technique. The resulting systems obtained were approximately 88 nm in size and negatively charged. Drug-release profiles demonstrated that a drug release was dependent on medium pH. Biodistribution of riluzole blended into solid lipid nanoparticles was carried out after administration to rats and the results were compared with those obtained by riluzole aqueous dispersion administration. Rats were sacrificed at time intervals of 8, 16 and 30 h, and the riluzole concentration in the blood and organs such as the brain, liver, spleen, heart and kidney was determined. It was demonstrated that these solid lipid nanoparticles were able to successfully carry riluzole into the CNS. Moreover, a low drug biodistribution in organs such as the liver, spleen, heart, kidneys and lung was found when riluzole was administered as drug-loaded solid lipid nanoparticles. Riluzole-loaded solid lipid nanoparticles showed colloidal size and high drug loading, a greater efficacy than free riluzole in rats, a higher capability to carry the drug into the brain and a lower indiscriminate biodistribution.

Specific binding of 125I-salmon calcitonin to rat brain

International Nuclear Information System (INIS)

Nakamuta, Hiromichi; Furukawa, Shinichi; Koida, Masao; Yajima, Haruaki; Orlowski, R.C.

1981-01-01

Rat brain particulate fraction was found to contain binding sites for 125 I-Salmon Calcitonin-I ( 125 I-SCT). Maximum binding occurred in the physiological pH range of 7.25 - 7.5. The binding reaction proceeded in a temperature-dependent manner. Binding sites were broadly distributed among the various rat brain regions and considerable regional differences existed in the affinity and density as detected by Scatchard analysis. The highest affinity was recorded in the case of the hypothalamus and the lowest in the case of the cerebellum. The KD (nM) and Bmax (pmole/mg protein) estimated for the binding to four regions were as follows: hypothalamus: 1.4 and 0.19, midbrain, hippocampus plus striatum: 1.5 and 0.08, pon plus medulla oblongata: 3.0 and 0.15 and cerebellum: 8.3 and 0.20. Using a particulate fraction of rat brain void of cerebellum and cortices, a binding assay for calcitonins was developed. Binding of 125 I-SCT was inhibited by unlabeled salmon, [Asu sup(1,7)]-eel and porcine calcitonins in a dose-dependent manner and the IC50s were 2.0, 8.0 and 30 nM, respectively. The IC50s were comparable to those estimated using a kidney particulate fraction. Human calcitonin, β-endorphin and substance P were weak inhibitors of the binding. Other peptides, drugs and putative neurotransmitters tested (totally 23 substances) failed to inhibit the binding at concentrations of 1.0 μM. The physiological significance of brain binding sites for calcitonin, with the possibility that the brain may possess endogenous ligands for these sites are discussed. (author)

Size-exclusion chromatographic reconstitution of the bovine brain benzodiazepine receptor : Effects of lipid environment on the binding characteristics

NARCIS (Netherlands)

Viel, G.T; Yang, Q; Lundahl, P; Ensing, K; de Zeeuw, R.A

1997-01-01

The benzodiazepine receptor from calf brain was solubilized with sodium deoxycholate (2 mg/ml) in the presence of 0.5 M KCl and protease inhibitors, and bound flunitrazepam with an equilibrium dissociation constant (K-d) of 2.7+/-1.2 nM and with 0.40+/-0.04 pmol binding sites per mg protein (B-max).

Snake cytotoxins bind to membranes via interactions with phosphatidylserine head groups of lipids.

Directory of Open Access Journals (Sweden)

Anastasia G Konshina

Full Text Available The major representatives of Elapidae snake venom, cytotoxins (CTs, share similar three-fingered fold and exert diverse range of biological activities against various cell types. CT-induced cell death starts from the membrane recognition process, whose molecular details remain unclear. It is known, however, that the presence of anionic lipids in cell membranes is one of the important factors determining CT-membrane binding. In this work, we therefore investigated specific interactions between one of the most abundant of such lipids, phosphatidylserine (PS, and CT 4 of Naja kaouthia using a combined, experimental and modeling, approach. It was shown that incorporation of PS into zwitterionic liposomes greatly increased the membrane-damaging activity of CT 4 measured by the release of the liposome-entrapped calcein fluorescent dye. The CT-induced leakage rate depends on the PS concentration with a maximum at approximately 20% PS. Interestingly, the effects observed for PS were much more pronounced than those measured for another anionic lipid, sulfatide. To delineate the potential PS binding sites on CT 4 and estimate their relative affinities, a series of computer simulations was performed for the systems containing the head group of PS and different spatial models of CT 4 in aqueous solution and in an implicit membrane. This was done using an original hybrid computational protocol implementing docking, Monte Carlo and molecular dynamics simulations. As a result, at least three putative PS-binding sites with different affinities to PS molecule were delineated. Being located in different parts of the CT molecule, these anion-binding sites can potentially facilitate and modulate the multi-step process of the toxin insertion into lipid bilayers. This feature together with the diverse binding affinities of the sites to a wide variety of anionic targets on the membrane surface appears to be functionally meaningful and may adjust CT action against

Lysosomal lipid storage diseases.

Science.gov (United States)

Schulze, Heike; Sandhoff, Konrad

2011-06-01

Lysosomal lipid storage diseases, or lipidoses, are inherited metabolic disorders in which typically lipids accumulate in cells and tissues. Complex lipids, such as glycosphingolipids, are constitutively degraded within the endolysosomal system by soluble hydrolytic enzymes with the help of lipid binding proteins in a sequential manner. Because of a functionally impaired hydrolase or auxiliary protein, their lipid substrates cannot be degraded, accumulate in the lysosome, and slowly spread to other intracellular membranes. In Niemann-Pick type C disease, cholesterol transport is impaired and unesterified cholesterol accumulates in the late endosome. In most lysosomal lipid storage diseases, the accumulation of one or few lipids leads to the coprecipitation of other hydrophobic substances in the endolysosomal system, such as lipids and proteins, causing a "traffic jam." This can impair lysosomal function, such as delivery of nutrients through the endolysosomal system, leading to a state of cellular starvation. Therapeutic approaches are currently restricted to mild forms of diseases with significant residual catabolic activities and without brain involvement.

Binding, folding and insertion of a β-hairpin peptide at a lipid bilayer surface: Influence of electrostatics and lipid tail packing.

Science.gov (United States)

Reid, Keon A; Davis, Caitlin M; Dyer, R Brian; Kindt, James T

2018-03-01

Antimicrobial peptides (AMPs) act as host defenses against microbial pathogens. Here we investigate the interactions of SVS-1 (KVKVKVKV d P l PTKVKVKVK), an engineered AMP and anti-cancer β-hairpin peptide, with lipid bilayers using spectroscopic studies and atomistic molecular dynamics simulations. In agreement with literature reports, simulation and experiment show preferential binding of SVS-1 peptides to anionic over neutral bilayers. Fluorescence and circular dichroism studies of a Trp-substituted SVS-1 analogue indicate, however, that it will bind to a zwitterionic DPPC bilayer under high-curvature conditions and folds into a hairpin. In bilayers formed from a 1:1 mixture of DPPC and anionic DPPG lipids, curvature and lipid fluidity are also observed to promote deeper insertion of the fluorescent peptide. Simulations using the CHARMM C36m force field offer complementary insight into timescales and mechanisms of folding and insertion. SVS-1 simulated at an anionic mixed POPC/POPG bilayer folded into a hairpin over a microsecond, the final stage in folding coinciding with the establishment of contact between the peptide's valine sidechains and the lipid tails through a "flip and dip" mechanism. Partial, transient folding and superficial bilayer contact are seen in simulation of the peptide at a zwitterionic POPC bilayer. Only when external surface tension is applied does the peptide establish lasting contact with the POPC bilayer. Our findings reveal the influence of disruption to lipid headgroup packing (via curvature or surface tension) on the pathway of binding and insertion, highlighting the collaborative effort of electrostatic and hydrophobic interactions on interaction of SVS-1 with lipid bilayers. Copyright © 2017 Elsevier B.V. All rights reserved.

Localization of cellular retinol-binding protein and retinol-binding protein in cells comprising the blood-brain barrier of rat and human

International Nuclear Information System (INIS)

MacDonald, P.N.; Ong, D.E.; Bok, D.

1990-01-01

Brain is not generally recognized as an organ that requires vitamin A, perhaps because no obvious histologic lesions have been observed in severely vitamin A-deficient animals. However, brain tissue does contain cellular vitamin A-binding proteins and a nuclear receptor protein for retinoic acid. In the present study, immunohistochemical techniques were used to determine the cell-specific location of cellular retinol-binding protein in human and rat brain tissue. Cellular retinol-binding protein was localized specifically within the cuboidal epithelial cells of the choroid plexus, two primary sites of the mammalian blood-brain barrier. In addition, autoradiographic procedures demonstrated binding sites for serum retinol-binding protein in the choroidal epithelium. These observations suggest that a significant movement of retinol across the blood-brain barrier may occur

Lactoferrin bioconjugated solid lipid nanoparticles: a new drug delivery system for potential brain targeting.

Science.gov (United States)

Singh, Indu; Swami, Rajan; Pooja, Deep; Jeengar, Manish Kumar; Khan, Wahid; Sistla, Ramakrishna

2016-01-01

Delivery of drugs to brain is a subtle task in the therapy of many severe neurological disorders. Solid lipid nanoparticles (SLN) easily diffuse the blood-brain barrier (BBB) due to their lipophilic nature. Furthermore, ligand conjugation on SLN surface enhances the targeting efficiency. Lactoferin (Lf) conjugated SLN system is first time attempted for effective brain targeting in this study. Preparation of Lf-modified docetaxel (DTX)-loaded SLN for proficient delivery of DTX to brain. DTX-loaded SLN were prepared using emulsification and solvent evaporation method and conjugation of Lf on SLN surface (C-SLN) was attained through carbodiimide chemistry. These lipidic nanoparticles were evaluated by DLS, AFM, FTIR, XRD techniques and in vitro release studies. Colloidal stability study was performed in biologically simulated environment (normal saline and serum). These lipidic nanoparticles were further evaluated for its targeting mechanism for uptake in brain tumour cells and brain via receptor saturation studies and distribution studies in brain, respectively. Particle size of lipidic nanoparticles was found to be optimum. Surface morphology (zeta potential, AFM) and surface chemistry (FTIR) confirmed conjugation of Lf on SLN surface. Cytotoxicity studies revealed augmented apoptotic activity of C-SLN than SLN and DTX. Enhanced cytotoxicity was demonstrated by receptor saturation and uptake studies. Brain concentration of DTX was elevated significantly with C-SLN than marketed formulation. It is evident from the cytotoxicity, uptake that SLN has potential to deliver drug to brain than marketed formulation but conjugating Lf on SLN surface (C-SLN) further increased the targeting potential for brain tumour. Moreover, brain distribution studies corroborated the use of C-SLN as a viable vehicle to target drug to brain. Hence, C-SLN was demonstrated to be a promising DTX delivery system to brain as it possessed remarkable biocompatibility, stability and efficacy than

Brain Levels of Prostaglandins, Endocannabinoids, and Related Lipids Are Affected by Mating Strategies

Directory of Open Access Journals (Sweden)

Jordyn M. Stuart

2013-01-01

Full Text Available Background. Endogenous cannabinoids (eCBs are involved in the development and regulation of reproductive behaviors. Likewise, prostaglandins (PGs drive sexual differentiation and initiation of ovulation. Here, we use lipidomics strategies to test the hypotheses that mating immediately activates the biosynthesis and/or metabolism of eCBs and PGs and that specific mating strategies differentially regulate these lipids in the brain. Methods. Lipid extractions and tandem mass spectrometric analysis were performed on brains from proestrous rats that had experienced one of two mating strategies (paced or standard mating and two nonmated groups (chamber exposed and home cage controls. Levels of PGs (PGE2 and PGF2alpha, eCBs (AEA and 2-AG, N-arachidonoyl glycine, and 4 related lipids (4 N-acylethanolamides were measured in olfactory bulb, hypothalamus, hippocampus, thalamus, striatum, midbrain, cerebellum, and brainstem. Results. Overall, levels of these lipids were significantly lower among paced compared to standard mated rats with the most dramatic decreases observed in brainstem, hippocampus, midbrain, and striatum. However, chamber exposed rats had significantly higher levels of these lipids compared to home cage controls and paced mated wherein the hippocampus showed the largest increases. Conclusions. These data demonstrate that mating strategies and exposure to mating arenas influence lipid signaling in the brain.

Thrombin binding to human brain and spinal cord

International Nuclear Information System (INIS)

McKinney, M.; Snider, R.M.; Richelson, E.

1983-01-01

Thrombin, a serine protease that regulates hemostasis, has been shown to stimulate the formation of cGMP in murine neuroblastoma cells. The nervous system in vivo thus may be postulated to respond to this blood-borne factor after it breaches the blood-brain barrier, as in trauma. Human alpha-thrombin was radiolabeled with 125I and shown to bind rapidly, reversibly, and with high affinity to human brain and spinal cord. These findings indicate the presence of specific thrombin-binding sites in nervous tissue and may have important clinical implications

Identification and in silico analysis of helical lipid binding regions in ...

Indian Academy of Sciences (India)

In supplementary table 1, all the results of the lipid binding region analysis for SecA from a number of ..... For those interested, a more detailed description will now be given for this particular analysis. First of ... MCPep Job Status Page Finished.

Discriminating binding and positioning of amphiphiles to lipid bilayers by {sup 1}H NMR

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Evanics, F. [Department of Chemistry, University of Toronto, UTM, 3359 Mississauga Rd. North Mississauga, Ont., L5L 1C6 (Canada); Prosser, R.S. [Department of Chemistry, University of Toronto, UTM, 3359 Mississauga Rd. North Mississauga, Ont., L5L 1C6 (Canada)]. E-mail: sprosser@utm.utoronto.ca

2005-04-04

The binding and positioning in lipid bilayers of three well-known drugs--imipramine, nicotine, and caffeine--have been studied using {sup 1}H NMR. The membrane model system consisted of 'fast-tumbling' lipid bicelles, in which a bilayered lipid domain, composed of the unsaturated lipid, 1,2-dimyristelaidoyl-sn-glycero-3-phosphocholine (DMLPC) was surrounded by a rim of deuterated detergent-like lipids, consisting of 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC-d22). Binding and immersion depth information was obtained by three experiments. (1) {sup 1}H chemical shift perturbations, upon transfer of the amphiphiles from water to a bicelle mixture, were used to estimate regions of the amphiphiles that interact with the membrane. (2) Water contact to resolvable protons was measured through a Nuclear Overhauser Effect (NOE) between water and resolvable drug and lipid resonances. In the case of both lipids and membrane bound drugs, positive NOEs with large cross-relaxation rates were measured for most resonances originating from the membrane hydrophilic region, while negative NOEs were observed predominantly to resonances in the hydrophobic region of the membrane. (3) {sup 1}H NMR measurements of oxygen-induced (paramagnetic) spin-lattice relaxation rates, which are known to increase with membrane immersion depth, were used to corroborate conclusions based on chemical shift perturbations and water-ligand NOEs.

PPAR-α, a lipid-sensing transcription factor, regulates blood-brain barrier efflux transporter expression.

Science.gov (United States)

More, Vijay R; Campos, Christopher R; Evans, Rebecca A; Oliver, Keith D; Chan, Gary Ny; Miller, David S; Cannon, Ronald E

2017-04-01

Lipid sensor peroxisome proliferator-activated receptor alpha (PPAR- α) is the master regulator of lipid metabolism. Dietary release of endogenous free fatty acids, fibrates, and certain persistent environmental pollutants, e.g. perfluoroalkyl fire-fighting foam components, are peroxisome proliferator-activated receptor alpha ligands. Here, we define a role for peroxisome proliferator-activated receptor alpha in regulating the expression of three ATP-driven drug efflux transporters at the rat and mouse blood-brain barriers: P-glycoprotein (Abcb1), breast cancer resistance protein (Bcrp/Abcg2), and multidrug resistance-associated protein 2 (Mrp2/Abcc2). Exposing isolated rat brain capillaries to linoleic acid, clofibrate, or PKAs increased the transport activity and protein expression of the three ABC transporters. These effects were blocked by the PPAR- α antagonist, GW6471. Dosing rats with 20 mg/kg or 200 mg/kg of clofibrate decreased the brain accumulation of the P-glycoprotein substrate, verapamil, by 50% (in situ brain perfusion; effects blocked by GW6471) and increased P-glycoprotein expression and activity in capillaries ex vivo. Fasting C57Bl/6 wild-type mice for 24 h increased both serum lipids and brain capillary P-glycoprotein transport activity. Fasting did not alter P-glycoprotein activity in PPAR- α knockout mice. These results indicate that hyperlipidemia, lipid-lowering fibrates and exposure to certain fire-fighting foam components activate blood-brain barrier peroxisome proliferator-activated receptor alpha, increase drug efflux transporter expression and reduce drug delivery to the brain.

[18F]haloperidol binding in baboon brain in vivo

International Nuclear Information System (INIS)

Yousef, Khalil A.; Fowler, Joanna S.; Volkow, Nora D.; Dewey, Stephen L.; Shea, Colleen; Schlyer, David J.; Gatley, S. John; Logan, Jean; Wolf, Alfred P.

1996-01-01

The binding of [ 18 F]haloperidol to dopamine D2 and to sigma recognition sites in baboon brain was examined using positron emission tomography (PET). Studies were performed at baseline and after treatment with either haloperidol (to evaluate saturability), (+)-butaclamol (which has specificity for dopamine D2 receptors) or (-)-butaclamol (which has specificity for sigma sites). Binding was widespread. Treatment with (-)-butaclamol had no effect, whereas (+)-butaclamol selectively reduced the uptake in striatum. Haloperidol increased the clearance rate from all brain regions. These results indicate that the binding profile of [ 18 F]haloperidol does not permit the selective examination of either dopamine D2 or sigma sites using PET

Lipid binding defects and perturbed synaptogenic activity of a Collybistin R290H mutant that causes epilepsy and intellectual disability.

Science.gov (United States)

Papadopoulos, Theofilos; Schemm, Rudolf; Grubmüller, Helmut; Brose, Nils

2015-03-27

Signaling at nerve cell synapses is a key determinant of proper brain function, and synaptic defects--or synaptopathies--are at the basis of many neurological and psychiatric disorders. In key areas of the mammalian brain, such as the hippocampus or the basolateral amygdala, the clustering of the scaffolding protein Gephyrin and of γ-aminobutyric acid type A receptors at inhibitory neuronal synapses is critically dependent upon the brain-specific guanine nucleotide exchange factor Collybistin (Cb). Accordingly, it was discovered recently that an R290H missense mutation in the diffuse B-cell lymphoma homology domain of Cb, which carries the guanine nucleotide exchange factor activity, leads to epilepsy and intellectual disability in human patients. In the present study, we determined the mechanism by which the Cb(R290H) mutation perturbs inhibitory synapse formation and causes brain dysfunction. Based on a combination of biochemical, cell biological, and molecular dynamics simulation approaches, we demonstrate that the R290H mutation alters the strength of intramolecular interactions between the diffuse B-cell lymphoma homology domain and the pleckstrin homology domain of Cb. This defect reduces the phosphatidylinositol 3-phosphate binding affinity of Cb, which limits its normal synaptogenic activity. Our data indicate that impairment of the membrane lipid binding activity of Cb and a consequent defect in inhibitory synapse maturation represent a likely molecular pathomechanism of epilepsy and mental retardation in humans. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

MR spectroscopy detection of lactate and lipid signals in the brains of healthy elderly people

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Sijens, P.E.; Heijboer, R.J.J.; Oudkerk, M. [Dept. of Radiology, Univ. Hospital Groningen (Netherlands); Heijer, T. den; Leeuw, F.E. de; Groot, J.C. de; Hofman, A.; Breteler, M.M.B. [Dept. of Epidemiology and Biostatistics, Erasmus University Medical School, Rotterdam (Netherlands); Achten, E. [Dept. of Magnetic Resonance, Gent University Hospital (Belgium)

2001-08-01

Magnetic resonance spectroscopy was used to assess the presence of brain lactate and lipid signals, frequently associated with the presence of pathology, in healthy persons of 60-90 years old (n=540). Lactate and lipid signals were observed in, respectively, 25 and 6% of women, and 18 and 2% of men. Upon adjustment for age, and for MRI-detected cerebral atrophy and white matter lesions, the gender differences in lactate and lipid remained the same (p=0.05 and p=0.03, respectively). Brain lactate and lipid signals appear to be intrinsic to aging. However, the presence of these metabolites in very focal areas only, rather than in any distributed fashion within the brain (the latter generally the case with cerebral atrophy and white matter lesions), strongly suggests the existence of asymptomatic focal pathology not shown on MRI. (orig.)

Distribution of [3H]diadenosine tetraphosphate binding sites in rat brain

International Nuclear Information System (INIS)

Miras-Portugal, M.T.; Palacios, J.M.; Torres, M.; Cortes, R.; Rodriguez-Pascual, F.

1997-01-01

The distribution of the diadenosine tetraphosphate high-affinity binding sites has been studied in rat brain by an autoradiographic method using [ 3 H]diadenosine tetraphosphate as the ligand. The binding characteristics are comparable to those described in studies performed on rat brain synaptosomes. White matter is devoid of specific binding. The range of binding site densities in gray matter varies from 3 to 15 fmol/mg of tissue, exhibiting a widespread but heterogeneous distribution. The highest densities correspond to the seventh cranial nerve, medial superior olive, pontine nuclei, glomerular and external plexiform layers of the olfactory bulb, and the granule cell layer of the cerebellar cortex. Intermediate density levels of binding correspond to different cortical areas, several nuclei of the amygdala, and the oriens and pyramidal layers of the hippocampal formation.The localization of diadenosine tetraphosphate binding sites in the brain may provide information on the places where diadenosine polyphosphate compounds can be expected to function in the central nervous system. (Copyright (c) 1997 Elsevier Science B.V., Amsterdam. All rights reserved.)

A Global Map of Lipid-Binding Proteins and Their Ligandability in Cells.

Science.gov (United States)

Niphakis, Micah J; Lum, Kenneth M; Cognetta, Armand B; Correia, Bruno E; Ichu, Taka-Aki; Olucha, Jose; Brown, Steven J; Kundu, Soumajit; Piscitelli, Fabiana; Rosen, Hugh; Cravatt, Benjamin F

2015-06-18

Lipids play central roles in physiology and disease, where their structural, metabolic, and signaling functions often arise from interactions with proteins. Here, we describe a set of lipid-based chemical proteomic probes and their global interaction map in mammalian cells. These interactions involve hundreds of proteins from diverse functional classes and frequently occur at sites of drug action. We determine the target profiles for several drugs across the lipid-interaction proteome, revealing that its ligandable content extends far beyond traditionally defined categories of druggable proteins. In further support of this finding, we describe a selective ligand for the lipid-binding protein nucleobindin-1 (NUCB1) and show that this compound perturbs the hydrolytic and oxidative metabolism of endocannabinoids in cells. The described chemical proteomic platform thus provides an integrated path to both discover and pharmacologically characterize a wide range of proteins that participate in lipid pathways in cells. Copyright © 2015 Elsevier Inc. All rights reserved.

Visualization of specific binding sites of benzodiazepine in human brain

International Nuclear Information System (INIS)

Shinotoh, H.; Yamasaki, T.; Inoue, O.; Itoh, T.; Suzuki, K.; Hashimoto, K.; Tateno, Y.; Ikehira, H.

1986-01-01

Using 11C-labeled Ro15-1788 and positron emission tomography, studies of benzodiazepine binding sites in the human brain were performed on four normal volunteers. Rapid and high accumulation of 11C activity was observed in the brain after i.v. injection of [11C]Ro15-1788, the maximum of which was within 12 min. Initial distribution of 11C activity in the brain was similar to the distribution of the normal cerebral blood flow. Ten minutes after injection, however, a high uptake of 11C activity was observed in the cerebral cortex and moderate uptake was seen in the cerebellar cortex, the basal ganglia, and the thalamus. The accumulation of 11C activity was low in the brain stem. This distribution of 11C activity was approximately parallel to the known distribution of benzodiazepine receptors. Saturation experiments were performed on four volunteers with oral administration of 0.3-1.8 mg/kg of cold Ro15-1788 prior to injection. Initial distribution of 11C activity following injection peaked within 2 min and then the accumulation of 11C activity decreased rapidly and remarkably throughout the brain. The results indicated that [11C] Ro15-1788 associates and dissociates to specific and nonspecific binding sites rapidly and has a high ratio of specific receptor binding to nonspecific binding in vivo. Carbon-11 Ro15-1788 is a suitable radioligand for the study of benzodiazepine receptors in vivo in humans

Autoradiographic localization of benzomorphan binding sites in rat brain

Energy Technology Data Exchange (ETDEWEB)

Crain, B.J.; Kwenjen Chang; McNamara, J.O.; Valdes, F.

1985-07-17

The benzomorphan subpopulation of opiate binding sites was labeled by (TH)diprenorphine in the presence of unlabeled ligands selected to quench and delta opiate binding sites. The distribution of benzomorphan binding sites was then localized autoradiographically. The distribution differs from the distributions of , delta and kappa opiate binding and is quite similar to the distribution of US -endorphin immunoreactivity. These observations support the hypothesis, based on biochemical studies in brain membranes, that benzomorphan binding sites may represent the ligand recognition sites of putative epsilon receptors. (Auth.). 34 refs.; 3 figs.

[{sup 18}F]haloperidol binding in baboon brain in vivo

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Yousef, Khalil A; Fowler, Joanna S; Volkow, Nora D; Dewey, Stephen L; Shea, Colleen; Schlyer, David J; Gatley, S John; Logan, Jean; Wolf, Alfred P

1996-01-01

The binding of [{sup 18}F]haloperidol to dopamine D2 and to sigma recognition sites in baboon brain was examined using positron emission tomography (PET). Studies were performed at baseline and after treatment with either haloperidol (to evaluate saturability), (+)-butaclamol (which has specificity for dopamine D2 receptors) or (-)-butaclamol (which has specificity for sigma sites). Binding was widespread. Treatment with (-)-butaclamol had no effect, whereas (+)-butaclamol selectively reduced the uptake in striatum. Haloperidol increased the clearance rate from all brain regions. These results indicate that the binding profile of [{sup 18}F]haloperidol does not permit the selective examination of either dopamine D2 or sigma sites using PET.

Evaluation of the application of chemical shift for the detection of lipid in brain lesion

Energy Technology Data Exchange (ETDEWEB)

Lim, C.J. [Department of Biomedical Imaging, Faculty of Medicine, University of Malaya Medical Centre, Kuala Lumpur (Malaysia); Ng, K.H., E-mail: ngkh@um.edu.m [Department of Biomedical Imaging, Faculty of Medicine, University of Malaya Medical Centre, Kuala Lumpur (Malaysia); Ramli, N.; Azman, R.R. [Department of Biomedical Imaging, Faculty of Medicine, University of Malaya Medical Centre, Kuala Lumpur (Malaysia)

2011-02-15

Non-invasive detection of the presence of lipids is particularly important in staging of intracranial tumours. Presence of lipid peak in aggressive intracranial tumours has been reported widely using MR spectroscopy. However this method has limitation due to long imaging time and artefacts formed by adjacent bones. Chemical shift MR imaging (with has shorter imaging time) is an alternative method that had been used to detect presence of lipid in vivo by means of signal intensity loss. The purpose of this study was to evaluate gradient echo in- and opposed-phase chemical shift pulse sequences for detection of lipid elements in brain lesion. Ten cylindered phantoms measuring 3 x 3 cm were filled with various mixtures of lipid and water: 0-90% lipid, in 10% step by weight. The gradient echo in- and opposed-phase chemical shift sequences were performed using a 1.5 T MRI (Magnetom Vision, Siemens) with a head coil. In addition, we performed MRI and chemical shift studies on 32 patients with brain lesion. We then analysed the association between out of phase intensity value and classification of the lesions. For phantom containing 50% lipid, maximum signal loss on opposed-phase images was observed. There were significant differences between in- and opposed-phase lipid-water phantom images (P = 0.0054). Most of the benign lesions fall into the positive out of phase intensity value, and malignant lesions fall into negative out of phase intensity value. We conclude that chemical shift artefact can be applied in detecting and characterising lipid elements in brain lesion.

Evaluation of the application of chemical shift for the detection of lipid in brain lesion

International Nuclear Information System (INIS)

Lim, C.J.; Ng, K.H.; Ramli, N.; Azman, R.R.

2011-01-01

Non-invasive detection of the presence of lipids is particularly important in staging of intracranial tumours. Presence of lipid peak in aggressive intracranial tumours has been reported widely using MR spectroscopy. However this method has limitation due to long imaging time and artefacts formed by adjacent bones. Chemical shift MR imaging (with has shorter imaging time) is an alternative method that had been used to detect presence of lipid in vivo by means of signal intensity loss. The purpose of this study was to evaluate gradient echo in- and opposed-phase chemical shift pulse sequences for detection of lipid elements in brain lesion. Ten cylindered phantoms measuring 3 x 3 cm were filled with various mixtures of lipid and water: 0-90% lipid, in 10% step by weight. The gradient echo in- and opposed-phase chemical shift sequences were performed using a 1.5 T MRI (Magnetom Vision, Siemens) with a head coil. In addition, we performed MRI and chemical shift studies on 32 patients with brain lesion. We then analysed the association between out of phase intensity value and classification of the lesions. For phantom containing 50% lipid, maximum signal loss on opposed-phase images was observed. There were significant differences between in- and opposed-phase lipid-water phantom images (P = 0.0054). Most of the benign lesions fall into the positive out of phase intensity value, and malignant lesions fall into negative out of phase intensity value. We conclude that chemical shift artefact can be applied in detecting and characterising lipid elements in brain lesion.

Agonist and antagonist binding to rat brain muscarinic receptors: influence of aging

International Nuclear Information System (INIS)

Gurwitz, D.; Egozi, Y.; Henis, Y.I.; Kloog, Y.; Sokolovsky, M.

1987-01-01

The objective of the present study was to determine the binding properties of muscarinic receptors in six brain regions in mature and old rats of both sexes by employing direct binding of [ 3 H]-antagonist as well as of the labeled natural neurotransmitter, [ 3 H]-acetylcholine [( 3 H]-AcCh). In addition, age-related factors were evaluated in the modulation processes involved in agonist binding. The results indicate that as the rat ages the density of the muscarinic receptors is altered differently in the various brain regions: it is decreased in the cerebral cortex, hippocampus, striatum and olfactory bulb of both male and female rats, but is increased (58%) in the brain stem of senescent males while no significant change is observed for females. The use of the highly sensitive technique measuring direct binding of [ 3 H]-AcCh facilitated the separate detection of age-related changes in the two classes (high- and low-affinity) of muscarinic agonist binding sites. In old female rats the density of high-affinity [ 3 H]-AcCh binding sites was preserved in all tissues studied, indicating that the decreases in muscarinic receptor density observed with [ 3 H]-antagonist represent a loss of low-affinity agonist binding sites. In contrast, [ 3 H]-AcCh binding is decreased in the hypothalamus and increased in the brain stem of old male rats. These data imply sexual dimorphism of the aging process in central cholinergic mechanisms

Nanodisc-Targeted STD NMR Spectroscopy Reveals Atomic Details of Ligand Binding to Lipid Environments.

Science.gov (United States)

Muñoz-García, Juan C; Inacio Dos Reis, Rosana; Taylor, Richard J; Henry, Alistair J; Watts, Anthony

2018-05-18

Saturation transfer difference (STD) NMR spectroscopy is one of the most popular ligand-based NMR techniques for the study of protein-ligand interactions. This is due to its robustness and the fact that it is focused on the signals of the ligand, without any need for NMR information on the macromolecular target. This technique is most commonly applied to systems involving different types of ligands (e.g., small organic molecules, carbohydrates or lipids) and a protein as the target, in which the latter is selectively saturated. However, only a few examples have been reported where membrane mimetics are the macromolecular binding partners. Here, we have employed STD NMR spectroscopy to investigate the interactions of the neurotransmitter dopamine with mimetics of lipid bilayers, such as nanodiscs, by saturation of the latter. In particular, the interactions between dopamine and model lipid nanodiscs formed either from charged or zwitterionic lipids have been resolved at the atomic level. The results, in agreement with previous isothermal titration calorimetry studies, show that dopamine preferentially binds to negatively charged model membranes, but also provide detailed atomic insights into the mode of interaction of dopamine with membrane mimetics. Our findings provide relevant structural information for the design of lipid-based drug carriers of dopamine and its structural analogues and are of general applicability to other systems. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Radioligand binding analysis of α 2 adrenoceptors with [11C]yohimbine in brain in vivo: Extended Inhibition Plot correction for plasma protein binding.

Science.gov (United States)

Phan, Jenny-Ann; Landau, Anne M; Jakobsen, Steen; Wong, Dean F; Gjedde, Albert

2017-11-22

We describe a novel method of kinetic analysis of radioligand binding to neuroreceptors in brain in vivo, here applied to noradrenaline receptors in rat brain. The method uses positron emission tomography (PET) of [ 11 C]yohimbine binding in brain to quantify the density and affinity of α 2 adrenoceptors under condition of changing radioligand binding to plasma proteins. We obtained dynamic PET recordings from brain of Spraque Dawley rats at baseline, followed by pharmacological challenge with unlabeled yohimbine (0.3 mg/kg). The challenge with unlabeled ligand failed to diminish radioligand accumulation in brain tissue, due to the blocking of radioligand binding to plasma proteins that elevated the free fractions of the radioligand in plasma. We devised a method that graphically resolved the masking of unlabeled ligand binding by the increase of radioligand free fractions in plasma. The Extended Inhibition Plot introduced here yielded an estimate of the volume of distribution of non-displaceable ligand in brain tissue that increased with the increase of the free fraction of the radioligand in plasma. The resulting binding potentials of the radioligand declined by 50-60% in the presence of unlabeled ligand. The kinetic unmasking of inhibited binding reflected in the increase of the reference volume of distribution yielded estimates of receptor saturation consistent with the binding of unlabeled ligand.

The effect of cytidine-diphosphate choline (CDP-choline) on brain lipid changes during aging

International Nuclear Information System (INIS)

De Medio, G.E.; Trovarelli, G.; Piccinin, G.L.; Porcellati, G.

1984-01-01

Lipid synthesis has been tested in vivo in different brain areas of 12-month-old male rats. Cortex, striatum, brainstem, and subcortex of brain have been examined. The cerebellum was discarded. Mixtures of (2- 3 H)glycerol and (Me- 14 C)choline were injected into the lateral ventricle of the brain as lipid precursors, and their incorporation into total lipid, water-soluble intermediates and choline-containing phospholipids was examined 1 hr after isotope injection. In another series of experiments cytidine-5'-diphosphate choline (CDP-choline) was injected intraventricularly to the aged rats 10 min before sacrifice with a simultaneous injection, and radioactivity assays were performed as above. Distribution of radioactivity content of CDP-choline among brain areas 10 min after its administration showed a noticeable enrichment of the nucleotide and water-soluble-related compounds in the examined areas, but to a lesser degree in the cerebral cortex. The incorporation of labelled glycerol, which is severely depressed in aged rats in all four areas [Gaiti et al, 1982, 1983], was increased only in the cortex, and apparently decreased in the other areas. This last result is probably due to a dilution effect brought about by the administered cold CDP-choline upon the ( 14 C)-containing water-soluble metabolites. As a consequence, the ( 3 H)/( 14 C) ratio in total lipid and in isolated phosphatidylcholine and choline plasmalogen increased after CDP-choline treatment

Distribution of [{sup 3}H]diadenosine tetraphosphate binding sites in rat brain

Energy Technology Data Exchange (ETDEWEB)

Miras-Portugal, M.T. [Departamento de Bioquimica, Facultad de Veterinaria, Universidad Complutense, 28040 Madrid (Spain); Palacios, J.M. [Laboratorios Almirall, Research Center, Cardener 68, 08024 Barcelona (Spain); Torres, M. [Departamento de Bioquimica, Facultad de Veterinaria, Universidad Complutense, 28040 Madrid (Spain); Cortes, R. [Departamento de Neuroquimica, Centro de Investigacion y Desarrollo, CSIC Jordi Girona 18-26, 08034 Barcelona (Spain); Rodriguez-Pascual, F. [Departamento de Bioquimica, Facultad de Veterinaria, Universidad Complutense, 28040 Madrid (Spain)

1997-01-06

The distribution of the diadenosine tetraphosphate high-affinity binding sites has been studied in rat brain by an autoradiographic method using [{sup 3}H]diadenosine tetraphosphate as the ligand. The binding characteristics are comparable to those described in studies performed on rat brain synaptosomes. White matter is devoid of specific binding. The range of binding site densities in gray matter varies from 3 to 15 fmol/mg of tissue, exhibiting a widespread but heterogeneous distribution. The highest densities correspond to the seventh cranial nerve, medial superior olive, pontine nuclei, glomerular and external plexiform layers of the olfactory bulb, and the granule cell layer of the cerebellar cortex. Intermediate density levels of binding correspond to different cortical areas, several nuclei of the amygdala, and the oriens and pyramidal layers of the hippocampal formation.The localization of diadenosine tetraphosphate binding sites in the brain may provide information on the places where diadenosine polyphosphate compounds can be expected to function in the central nervous system. (Copyright (c) 1997 Elsevier Science B.V., Amsterdam. All rights reserved.)

Binding of tritiated corticosterone in brain sections of adrenalectomized rat

International Nuclear Information System (INIS)

Sarrieau, A.; Vial, M.; Dussaillant, M.; Rostene, W.; Philibert, P.

1983-01-01

A new technique which permits to study the specific binding of tritiated corticosterone in brain sections of adrenalectomized rats is described. Under these conditions, the specific binding of the glucocorticoid represents 60 to 70% of the initial binding. The apparent dissociation constant and the number of binding sites, determined by Scatchard analysis, are in the range of 10 -8 M and 100 fmoles/mg of protein respectively [fr

Effect of dietary docosahexaenoic acid connecting phospholipids on the lipid peroxidation of the brain in mice.

Science.gov (United States)

Hiratsuka, Seiichi; Ishihara, Kenji; Kitagawa, Tomoko; Wada, Shun; Yokogoshi, Hidehiko

2008-12-01

The effect of dietary docosahexaenoic acid (DHA, C22:6n-3) with two lipid types on lipid peroxidation of the brain was investigated in streptozotocin (STZ)-induced diabetic mice. Each group of female Balb/c mice was fed a diet containing DHA-connecting phospholipids (DHA-PL) or DHA-connecting triacylglycerols (DHA-TG) for 5 wk. Safflower oil was fed as the control. The lipid peroxide level of the brain was significantly lower in the mice fed the DHA-PL diet when compared to those fed the DHA-TG and safflower oil diets, while the alpha-tocopherol level was significantly higher in the mice fed the DHA-PL diet than in those fed the DHA-TG and safflower oil diets. The DHA level of phosphatidylethanolamine in the brain was significantly higher in the mice fed the DHA-PL diet than in those fed the safflower oil diet. The dimethylacetal levels were significantly higher in the mice fed the DHA-PL diet than in those fed the safflower oil and DHA-TG diets. These results suggest that the dietary DHA-connecting phospholipids have an antioxidant activity on the brain lipids in mice, and the effect may be related to the brain plasmalogen.

Lipid Binding of the Amphipathic Helix Serving as Membrane Anchor of Pestivirus Glycoprotein Erns.

Science.gov (United States)

Aberle, Daniel; Oetter, Kay-Marcus; Meyers, Gregor

2015-01-01

Pestiviruses express a peculiar protein named Erns representing envelope glycoprotein and RNase, which is important for control of the innate immune response and persistent infection. The latter functions are connected with secretion of a certain amount of Erns from the infected cell. Retention/secretion of Erns is most likely controlled by its unusual membrane anchor, a long amphipathic helix attached in plane to the membrane. Here we present results of experiments conducted with a lipid vesicle sedimentation assay able to separate lipid-bound from unbound protein dissolved in the water phase. Using this technique we show that a protein composed of tag sequences and the carboxyterminal 65 residues of Erns binds specifically to membrane vesicles with a clear preference for compositions containing negatively charged lipids. Mutations disturbing the helical folding and/or amphipathic character of the anchor as well as diverse truncations and exchange of amino acids important for intracellular retention of Erns had no or only small effects on the proteins membrane binding. This result contrasts the dramatically increased secretion rates observed for Erns proteins with equivalent mutations within cells. Accordingly, the ratio of secreted versus cell retained Erns is not determined by the lipid affinity of the membrane anchor.

Lipid Binding of the Amphipathic Helix Serving as Membrane Anchor of Pestivirus Glycoprotein Erns.

Directory of Open Access Journals (Sweden)

Daniel Aberle

Full Text Available Pestiviruses express a peculiar protein named Erns representing envelope glycoprotein and RNase, which is important for control of the innate immune response and persistent infection. The latter functions are connected with secretion of a certain amount of Erns from the infected cell. Retention/secretion of Erns is most likely controlled by its unusual membrane anchor, a long amphipathic helix attached in plane to the membrane. Here we present results of experiments conducted with a lipid vesicle sedimentation assay able to separate lipid-bound from unbound protein dissolved in the water phase. Using this technique we show that a protein composed of tag sequences and the carboxyterminal 65 residues of Erns binds specifically to membrane vesicles with a clear preference for compositions containing negatively charged lipids. Mutations disturbing the helical folding and/or amphipathic character of the anchor as well as diverse truncations and exchange of amino acids important for intracellular retention of Erns had no or only small effects on the proteins membrane binding. This result contrasts the dramatically increased secretion rates observed for Erns proteins with equivalent mutations within cells. Accordingly, the ratio of secreted versus cell retained Erns is not determined by the lipid affinity of the membrane anchor.

The Role of ATP-Binding Cassette Transporters in Neuro-Inflammation: Relevance for Bioactive Lipids

NARCIS (Netherlands)

Kooij, G.; van Horssen, J.; Bandaru, V.V.R.; Haughey, N.J.; de Vries, H.E.

2012-01-01

ATP-binding cassette (ABC) transporters are highly expressed by brain endothelial cells that form the blood-brain barrier (BBB). These efflux pumps play an important role in maintaining brain homeostasis as they actively hinder the entry of unwanted blood-derived compounds into the central nervous

Systematic Approach for the Formulation and Optimization of Solid Lipid Nanoparticles of Efavirenz by High Pressure Homogenization Using Design of Experiments for Brain Targeting and Enhanced Bioavailability

Science.gov (United States)

Gupta, Shweta; Kesarla, Rajesh; Chotai, Narendra; Misra, Ambikanandan

2017-01-01

The nonnucleoside reverse transcriptase inhibitors, used for the treatment of HIV infections, are reported to have low bioavailability pertaining to high first-pass metabolism, high protein binding, and enzymatic metabolism. They also show low permeability across blood brain barrier. The CNS is reported to be the most important HIV reservoir site. In the present study, solid lipid nanoparticles of efavirenz were prepared with the objective of providing increased permeability and protection of drug due to biocompatible lipidic content and nanoscale size and thus developing formulation having potential for enhanced bioavailability and brain targeting. Solid lipid nanoparticles were prepared by high pressure homogenization technique using a systematic approach of design of experiments (DoE) and evaluated for particle size, polydispersity index, zeta potential, and entrapment efficiency. Particles of average size 108.5 nm having PDI of 0.172 with 64.9% entrapment efficiency were produced. Zeta potential was found to be −21.2 mV and the formulation was found stable. The in-vivo pharmacokinetic studies revealed increased concentration of the drug in brain, as desired, when administered through intranasal route indicating its potential for an attempt towards complete eradication of HIV and cure of HIV-infected patients. PMID:28243600

Insulin binding to brain capillaries is reduced in genetically obese, hyperinsulinemic Zucker rats

International Nuclear Information System (INIS)

Schwartz, M.W.; Figlewicz, D.F.; Kahn, S.E.; Baskin, D.G.; Greenwood, M.R.; Porte, D. Jr.

1990-01-01

In order to study the role of plasma insulin in regulating the binding of insulin to the endothelium of the blood-brain barrier (BBB), insulin binding to a purified preparation of brain capillaries was measured in both genetically obese Zucker rats and lean Zucker controls. We found a reduction of 65% in brain capillary insulin binding site number in the obese compared to lean rats with no change in receptor affinity. Furthermore, specific insulin binding to brain capillaries was negatively correlated (p less than 0.05) to the plasma insulin level, suggesting a role for plasma insulin in regulating insulin binding. A similar relationship was observed between insulin receptor number in liver membranes and the plasma insulin level. We conclude that obese, hyperinsulinemic Zucker rats exhibit a reduction in the number of BBB insulin receptors, which parallels the reduction seen in other peripheral tissues. Since insulin receptors have been hypothesized to participate in the transport of insulin across the BBB, the reduction observed in the obese rats may account for the decrease in cerebrospinal fluid insulin uptake previously demonstrated in these animals

Mass Spectrometry Imaging Shows Cocaine and Methylphenidate Have Opposite Effects on Major Lipids in Drosophila Brain.

Science.gov (United States)

Philipsen, Mai H; Phan, Nhu T N; Fletcher, John S; Malmberg, Per; Ewing, Andrew G

2018-03-20

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) was used to study the effects of cocaine versus methylphenidate administration on both the localization and abundance of lipids in Drosophila melanogaster brain. A J105 ToF-SIMS with a 40 keV gas cluster primary ion source enabled us to probe molecular ions of biomolecules on the fly with a spatial resolution of ∼3 μm, giving us unique insights into the effect of these drugs on molecular lipids in the nervous system. Significant changes in phospholipid composition were observed in the central brain for both. Principal components image analysis revealed that changes occurred mainly for phosphatidylcholines, phosphatidylethanolamines, and phosphatidylinositols. When the lipid changes caused by cocaine were compared with those induced by methylphenidate, it was shown that these drugs exert opposite effects on the brain lipid structure. We speculate that this might relate to the molecular mechanism of cognition and memory.

High-affinity cannabinoid binding site in brain: A possible marijuana receptor

International Nuclear Information System (INIS)

Nye, J.S.

1988-01-01

The mechanism by which delta 9 tetrahydrocannabinol (delta 9 THC), the major psychoactive component of marijuana or hashish, produces its potent psychological and physiological effects is unknown. To find receptor binding sites for THC, we designed a water-soluble analog for use as a radioligand. 5'-Trimethylammonium-delta 8 THC (TMA) is a positively charged analog of delta- 8 THC modified on the 5' carbon, a portion of the molecule not important for its psychoactivity. We have studied the binding of [ 3 H]-5'-trimethylammonium-delta- 8 THC ([ 3 H]TMA) to rat neuronal membranes. [ 3 H]TMA binds saturably and reversibly to brain membranes with high affinity to apparently one class of sites. Highest binding site density occurs in brain, but several peripheral organs also display specific binding. Detergent solubilizes the sites without affecting their pharmacologial properties. Molecular sieve chromatography reveals a bimodal peak of [ 3 H]TMA binding activity of approximately 60,000 daltons apparent molecular weight

The multiple roles of Fatty Acid Handling Proteins in brain

Directory of Open Access Journals (Sweden)

Valentine SF Moullé

2012-09-01

Full Text Available Lipids are essential components of a living organism as energy source but also as constituent of the membrane lipid bilayer. In addition fatty acid (FA derivatives interact with many signaling pathways. FAs have amphipathic properties and therefore require being associated to protein for both transport and intracellular trafficking. Here we will focus on several fatty acid handling proteins, among which the fatty acid translocase/CD36 (FAT/CD36, members of fatty acid transport proteins (FATPs, and lipid chaperones fatty acid-binding proteins (FABPs. A decade of extensive studies has helped decipher the mechanism of action of these proteins in peripheral tissue with high lipid metabolism. However, considerably less information is available regarding their role in the brain, despite the high lipid content of this tissue. This review will primarily focus on the recent studies that have highlighted the crucial role of lipid handling proteins in brain FA transport, neuronal differentiation and development, cognitive processes and brain diseases. Finally a special focus will be made on the recent studies that have revealed the role of FAT/CD36 in brain lipid sensing and nervous control of energy balance.

Radioligand binding analysis of α 2 adrenoceptors with [11C]yohimbine in brain in vivo: Extended Inhibition Plot correction for plasma protein binding

DEFF Research Database (Denmark)

Phan, Jenny-Ann; Landau, Anne M.; Jakobsen, Steen

2017-01-01

We describe a novel method of kinetic analysis of radioligand binding to neuroreceptors in brain in vivo, here applied to noradrenaline receptors in rat brain. The method uses positron emission tomography (PET) of [11C]yohimbine binding in brain to quantify the density and affinity of α 2...... Inhibition Plot introduced here yielded an estimate of the volume of distribution of non-displaceable ligand in brain tissue that increased with the increase of the free fraction of the radioligand in plasma. The resulting binding potentials of the radioligand declined by 50-60% in the presence of unlabeled...

The effect of infectious brain edema on NMDA receptor binding in rat's brain

International Nuclear Information System (INIS)

Cheng Guansheng; Chen Jianfang; Chen Xiang

1997-01-01

PURPOSE: The effect of the infectious brain edema (IBE) induced by Bordetella Pertussis (BP) on the specific binding of 3 H MK-801 in rat's brain in vivo was determined. METHODS: BP was injected via left internal carotid artery in rat model of infectious brain edema. Male SD rats were divided into three groups: 1) Group control (NS, n = 11); 2) Group IBF (BP, n = 12); 3) Group pretreatment of MK-801 + PB (MK-801, n = 4). Normal saline or BP 0.2 ml/kg was injected into left internal carotid artery in NS and BP group respectively. MK-801 0.5 mg/kg per day was injected i.p. two days before injection of BP in group MK-801. Rats were killed by decapitation at 24 hours after injection of BP. The specific binding of N-methyl-D-aspartate (NMDA) receptor were measured with 3 H-MK-801 in the neuronal membrane of cerebral cortex. The Scatchard plots were performed. RESULTS: The B max values were 0.623 +- 0.082 and 0.606 +- 0.087 pmol/mg protein in group NS and BP respectively (t = 0.48, P>0.05). The Kd values were 43.1 +- 4.2 and 30.5 +- 3.0 nmol/L in group NS and BP respectively (t = 7.8, P<0.05). The specific binding of NMDA receptor was decreased by pretreatment of MK-801. CONCLUSIONS: The total number of NMDA receptor had not changed, whereas its affinity increased significantly in the model of brain edema induced by pertussis bacilli in rat. The increase of affinity of NMDA receptor can be blockaded by MK-801 pretreatment in vivo

Heterogeneous binding of sigma radioligands in the rat brain and liver

International Nuclear Information System (INIS)

Ross, S.B.

1991-01-01

The binding of four sigma receptor ligands, 3 H-(+)-N-allyl-N-normetazocine ( 3 H-(+)-SKF 10,047), 3 H-(+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine ( 3 H-(+)-3-PPP), 3 H-haloperidol and 3 H-N,N'-di(o-totyl)guanidine ( 3 H-DTG), and the cytochrome P450IID6 ligand and dopamine uptake inhibitor 3 H-1-[2-(diphenylmethoxy)ethyl]-4-(3-phenylpropyl)piperazine ( 3 H-GBR 12935) to membranal preparations of rat liver or whole rat brain was examined regarding kinetical properties and inhibition by various compounds with affinity for sigma binding sites or cytochrome P-450. In rat brain the density of binding sites was increased in order (+)-SKF 10,047 3 H-(+)-SKF 10,047 there were quite marked differences between the ligands studied. Multiple binding sites were also indicated by the low Hill coefficients found for most of the compounds studied. It was found that the cytochrome P-450 inhibitor proadifen (SKF 525A), like haloperidol, was a potent inhibitor of the binding of 3 H-(+)-SKF 10,047, 3 H-(+)-3-PPP and 3 H-haloperidol to the liver and brain preparations, less active in inhibiting the binding of 3 H-DTG and least effective on the binding of 3 H-GBR 12935. Another cytochrome P-450 inhibitor, L-lobeline, was particularly potent in inhibiting the binding of 3 H-DTG but was also quite potent inhibitor of the binding of the other sigma ligands. It was less potent in inhibiting the binding of 3 H-GBR 12935. The binding of the latter ligand was potently inhibited by the analogous compound GBR 12909 but of the other compounds examined only L-lobeline, proadifen, haloperidol, DTG and (+)-3-PPP had IC50 values below 10 μM. The possibility that the sigma binding sites are identical with some subforms of cytochrome P-450 is discussed. (author)

Quantitative autoradiography of [3H]ouabain binding sites in rat brain

International Nuclear Information System (INIS)

Spyropoulos, A.C.; Rainbow, T.C.

1984-01-01

In vitro quantitative autoradiography was used to localize in rat brain binding sites for [ 3 H]ouabain, an inhibitor of the Na + ,K + -ATPase. High levels of [ 3 H]ouabain sites were found in the superior and inferior colliculi, the mammillary nucleus, the interpeduncular nucleus, and in various divisions of the olfactory, auditory and somatomotor systems. The heterogeneous distribution of [ 3 H]ouabain binding closely parallels the regional brain glucose consumption as determined by the [ 14 C]deoxyglucose method. Lesion studies of the rat hippocampus using the excitotoxin, ibotenic acid, showed both a marked decrease of neuronal cell types on the injected side and a corresponding decrease in [ 3 H]ouabain binding, indicating that some of the [ 3 H]ouabain binding sites are localized to neurons. The close correlation between [ 3 H]ouabain binding and regional glucose utilization provides further evidence for a linkage between glucose utilization and the neuronal Na + ,K + -ATPase. (Auth.)

Serine 77 in the PDZ domain of PICK1 is a protein kinase Cα phosphorylation site regulated by lipid membrane binding

DEFF Research Database (Denmark)

Ammendrup-Johnsen, Ina; Thorsen, Thor Seneca; Gether, Ulrik

2012-01-01

PICK1 (protein interacting with C kinase 1) contains an N-terminal protein binding PDZ domain and a C-terminal lipid binding BAR domain. PICK1 plays a key role in several physiological processes, including synaptic plasticity. However, little is known about the cellular mechanisms governing the a...... lipid binding and/or polymerization capacity. We propose that PICK1 is phosphorylated at Ser77 by PKCα preferentially when bound to membrane vesicles and that this phosphorylation in turn modulates its cellular distribution....

Characterization of [³H] oxymorphone binding sites in mouse brain

DEFF Research Database (Denmark)

Yoo, Ji Hoon; Borsodi, Anna; Tóth, Géza

2017-01-01

Oxymorphone, one of oxycodone's metabolic products, is a potent opioid receptor agonist which is thought to contribute to the analgesic effect of its parent compound and may have high potential abuse liability. Nonetheless, the in vivo pharmacological binding profile of this drug is still unclear....... This study uses mice lacking mu (MOP), kappa (KOP) or delta (DOP) opioid receptors as well as mice lacking all three opioid receptors to provide full characterisation of oxymorphone binding sites in the brain. Saturation binding studies using [3H]oxymorphone revealed high affinity binding sites in mouse......]Oxymorphone binding was completely abolished across the majority of the brain regions in mice lacking MOP as well as in mice lacking all three opioid receptors. DOP and KOP knockout mice retained [3H]oxymorphone binding sites suggesting oxymorphone may not target DOP or KOP. These results confirm that the MOP...

Immunochemical characterization of the brain glutamate binding protein

International Nuclear Information System (INIS)

Roy, S.

1986-01-01

A glutamate binding protein (GBP) was purified from bovine and rat brain to near homogeneity. Polyclonal antibodies were raised against this protein. An enzyme-linked-immunosorbent-assay was used to quantify and determine the specificity of the antibody response. The antibodies were shown to strongly react with bovine brain GBP and the analogous protein from rat brain. The antibodies did not show any crossreactivity with the glutamate metabolizing enzymes, glutamate dehydrogenase, glutamine synthetase and glutamyl transpeptidase, however it crossreacted moderately with glutamate decarboxylase. The antibodies were also used to define the possible physiologic activity of GBP in synaptic membranes. The antibodies were shown: (i) to inhibit the excitatory amino-acid stimulation of thiocyanate (SCN)flux, (ii) had no effect on transport of L-Glutamic acid across the synaptic membrane, and (iii) had no effect on the depolarization-induced release of L-glutamate. When the anti-GBP antibodies were used to localize and quantify the GBP distribution in various subcellular fractions and in brain tissue samples, it was found that the hippocampus had the highest immunoreactivity followed by the cerebral cortex, cerebellar cortex and caudate-putamen. The distribution of immunoreactivity in the subcellular fraction were as follows: synaptic membranes > crude mitochondrial fraction > homogenate > myelin. In conclusion these studies suggest that: (a) the rat brain GBP and the bovine brain GBP are immunologically homologous protein, (b) there are no structural similarities between the GBP and the glutamate metabolizing enzymes with the exception of glutamate decarboxylase and (c) the subcellular and regional distribution of the GBP immunoreactivity followed a similar pattern as observed for L-[ 3 H]-binding

Drug binding and mobility relating to the thermal fluctuation in fluid lipid membranes

Science.gov (United States)

Okamura, Emiko; Yoshii, Noriyuki

2008-12-01

Drug binding and mobility in fluid lipid bilayer membranes are quantified in situ by using the multinuclear solution NMR combined with the pulsed-field-gradient technique. One-dimensional and pulsed-field-gradient F19 and H1 NMR signals of an anticancer drug, 5-fluorouracil (5FU) are analyzed at 283-313 K in the presence of large unilamellar vesicles (LUVs) of egg phosphatidylcholine (EPC) as model cell membranes. The simultaneous observation of the membrane-bound and free 5FU signals enables to quantify in what amount of 5FU is bound to the membrane and how fast 5FU is moving within the membrane in relation to the thermal fluctuation of the soft, fluid environment. It is shown that the mobility of membrane-bound 5FU is slowed down by almost two orders of magnitude and similar to the lipid movement in the membrane, the movement closely related to the intramembrane fluidity. The mobility of 5FU and EPC is, however, not similar at 313 K; the 5FU movement is enhanced in the membrane as a result of the loose binding of 5FU in the lipid matrices. The membrane-bound fraction of 5FU is ˜0.1 and almost unaltered over the temperature range examined. It is also independent of the 5FU concentration from 2 to 30 mM with respect to the 40-50 mM LUV. The free energy of the 5FU binding is estimated at -4 to -2 kJ/mol, the magnitude always close to the thermal fluctuation, 2.4-2.6 kJ/mol.

An autoradiographic map of (3H)diprenorphine binding in rat brain: effects of social interaction

International Nuclear Information System (INIS)

Panksepp, J.; Bishop, P.

1981-01-01

(3H)Diprenorphine binding was analyzed autoradiographically in the brains of 33 day old rat pups. A photographic atlas of diprenorphine binding in the coronal plane is provided to highlight the dispersion of opioid receptor systems through the brain. To determine whether brain opioid release may be induced by social interactions, half the animals were sacrificed following a 30 min period of social interaction while the other half were sacrificed following 30 min of social isolation. Opioid binding was higher in isolate-tested animals than socially-tested ones, suggesting that social interaction may promote endogenous brain opioid release

Pet imaging of peripheral benzodiazepine binding sites in brain tumors

International Nuclear Information System (INIS)

Junck, L.; Jewett, D.M.; Olsen, J.M.; Kilbourn, M.R.; Koeppe, R.A.; Young, A.B.; Greenberg, H.S.; Kuhl, D.E.

1991-01-01

Studies in vitro have shown that the peripheral-type benzodiazepine binding site (PBBS) is present in moderate to high density on malignant gliomas as well as in areas of reactive gliosis, but in low density in normal brain. PK 11195 is an isoquinoline derivative that binds selectively to the PBBS but not to the central benzodiazepine receptor. We have used [ 11 C]PK 11195 with positron emission tomography (PET) to study brain tumors and cerebral infarcts. Preliminary results showed that, in 13 of 18 patients with astrocytomas, [ 11 C]PK 11195 radioactivity was increased in tumor compared to remote brain and that the concentration ratios of tumor-to-remote brain were higher for high grade astrocytomas than for low grade astrocytomas. Pharmacokinetic analysis suggests that the increased activity in tumor probably does not result from alterations in blood flow or vascular permeability. Patients with lymphoma, meningioma, medulloblastoma, brain metastasis, and neurosarcoidosis have also shown increased radioactivity in tumor. Among eight patients with acute and subacute cerebral infarcts, activity in the infarct was increased in seven and was often greatest at the periphery. We conclude that [ 11 C]PK 11195 is a promising radiopharmaceutical for further investigation of brain tumors as well as diseases characterized by reactive gliosis

Physicochemical characterization and in vivo bioluminescence imaging of nanostructured lipid carriers for targeting the brain: apomorphine as a model drug

Energy Technology Data Exchange (ETDEWEB)

Hsu, Shu-Hui [Department of Pharmacy, Chia Nan University of Pharmacy and Science, Tainan 717, Taiwan (China); Wen, Chih-Jen; Yen, Tzu-Chen [Animal Molecular Imaging Center, Chang Gung Memorial Hospital, Kweishan, Taoyuan 333, Taiwan (China); Al-Suwayeh, S A; Fang, Jia-You [Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh (Saudi Arabia); Chang, Hui-Wen, E-mail: fajy@mail.cgu.edu.tw [Pharmaceutics Laboratory, Graduate Institute of Natural Products, Chang Gung University, Kweishan, Taoyuan 333, Taiwan (China)

2010-10-08

Nanostructured lipid carriers (NLCs) were prepared to investigate whether the duration of brain targeting and accumulation of drugs in the brain can be improved by intravenous delivery. NLCs were developed using cetyl palmitate as the lipid matrix, squalene as the cationic surfactant, and Pluronic F68, polysorbate 80 and polyethylene glycol as the interfacial additives. Solid lipid nanoparticles (SLNs) and lipid emulsions (LEs) were also prepared for comparison. An anti-Parkinson's drug, apomorphine, was used as the model drug. Nuclear magnetic resonance and differential scanning calorimetry showed possible interactions between the solid and liquid lipids in the inner core. The lipid nanoparticles with different compositions were characterized by mean size, zeta potential, apomorphine encapsulation and in vitro drug release. NLCs were 370-430 nm in size, which was between the sizes of the SLNs and LEs. A cationic surfactant was used to produce a positive surface charge of 42-50 mV. The base form of apomorphine was successfully entrapped by NLCs with an entrapment percentage of > 60%. The loading of apomorphine in nanoparticles resulted in a slower release behavior compared to the aqueous solution, with LEs showing the lowest release. In vivo real-time bioluminescence imaging of the rat brain revealed that NLCs could be targeted, through certain vessels, to selected brain regions. This effect was further confirmed by imaging the entire brain and brain slices. The results indicated that NLCs with moderate additives are a promising controlled-release and drug-targeting system.

Physicochemical characterization and in vivo bioluminescence imaging of nanostructured lipid carriers for targeting the brain: apomorphine as a model drug

International Nuclear Information System (INIS)

Hsu, Shu-Hui; Wen, Chih-Jen; Yen, Tzu-Chen; Al-Suwayeh, S A; Fang, Jia-You; Chang, Hui-Wen

2010-01-01

Nanostructured lipid carriers (NLCs) were prepared to investigate whether the duration of brain targeting and accumulation of drugs in the brain can be improved by intravenous delivery. NLCs were developed using cetyl palmitate as the lipid matrix, squalene as the cationic surfactant, and Pluronic F68, polysorbate 80 and polyethylene glycol as the interfacial additives. Solid lipid nanoparticles (SLNs) and lipid emulsions (LEs) were also prepared for comparison. An anti-Parkinson's drug, apomorphine, was used as the model drug. Nuclear magnetic resonance and differential scanning calorimetry showed possible interactions between the solid and liquid lipids in the inner core. The lipid nanoparticles with different compositions were characterized by mean size, zeta potential, apomorphine encapsulation and in vitro drug release. NLCs were 370-430 nm in size, which was between the sizes of the SLNs and LEs. A cationic surfactant was used to produce a positive surface charge of 42-50 mV. The base form of apomorphine was successfully entrapped by NLCs with an entrapment percentage of > 60%. The loading of apomorphine in nanoparticles resulted in a slower release behavior compared to the aqueous solution, with LEs showing the lowest release. In vivo real-time bioluminescence imaging of the rat brain revealed that NLCs could be targeted, through certain vessels, to selected brain regions. This effect was further confirmed by imaging the entire brain and brain slices. The results indicated that NLCs with moderate additives are a promising controlled-release and drug-targeting system.

Interaction of D-LSD with binding sites in brain: a study in vivo and in vitro

International Nuclear Information System (INIS)

Ebersole, B.L.J.

1985-01-01

The localization of [ 3 H]-d-lysergic acid diethylamide ([ 3 H]LSD) binding sites in the mouse brain was compared in vivo and in vitro. Radioautography of brain sections incubated with [ 3 H]LSD in vitro revealed substantial specific [ 3 H]LSD binding in cortical layers III-IV and areas CA1 and dentate gyrus in hippocampus. In contrast, in brain sections from animals that received [ 3 H]LSD in vivo, binding in hippocampus was scant and diffuse, although the pattern of labeling in cortex was similar to that seen in vitro. The low specific binding in hippocampus relative to cortex was confirmed by homogenate filtration studies of brain areas from mice that received injections of [ 3 H]LSD. Time-course studies established that peak specific binding at ten minutes was the same in cortex and hippocampus. At all times, binding in hippocampus was about one-third of that in cortex; in contrast, the concentration of free [ 3 H]LSD did not vary between regions. This finding was unexpected, because binding studies in vitro in membrane preparations indicated that the density and affinity of [ 3 H]LSD binding sites were similar in both brain regions. Saturation binding studies in vivo showed that the lower amount of [ 3 H]LSD binding in hippocampus was attributable to a lower density of sites labeled by [ 3 H]LSD. The pharmacological identify of [ 3 H]LSD binding sites in vivo may be relevant to the hallucinogenic properties of LSD and of other related hallucinogens

Identifying the Interaction of Vancomycin With Novel pH-Responsive Lipids as Antibacterial Biomaterials Via Accelerated Molecular Dynamics and Binding Free Energy Calculations.

Science.gov (United States)

Ahmed, Shaimaa; Vepuri, Suresh B; Jadhav, Mahantesh; Kalhapure, Rahul S; Govender, Thirumala

2018-06-01

Nano-drug delivery systems have proven to be an efficient formulation tool to overcome the challenges with current antibiotics therapy and resistance. A series of pH-responsive lipid molecules were designed and synthesized for future liposomal formulation as a nano-drug delivery system for vancomycin at the infection site. The structures of these lipids differ from each other in respect of hydrocarbon tails: Lipid1, 2, 3 and 4 have stearic, oleic, linoleic, and linolenic acid hydrocarbon chains, respectively. The impact of variation in the hydrocarbon chain in the lipid structure on drug encapsulation and release profile, as well as mode of drug interaction, was investigated using molecular modeling analyses. A wide range of computational tools, including accelerated molecular dynamics, normal molecular dynamics, binding free energy calculations and principle component analysis, were applied to provide comprehensive insight into the interaction landscape between vancomycin and the designed lipid molecules. Interestingly, both MM-GBSA and MM-PBSA binding affinity calculations using normal molecular dynamics and accelerated molecular dynamics trajectories showed a very consistent trend, where the order of binding affinity towards vancomycin was lipid4 > lipid1 > lipid2 > lipid3. From both normal molecular dynamics and accelerated molecular dynamics, the interaction of lipid3 with vancomycin is demonstrated to be the weakest (∆G binding  = -2.17 and -11.57, for normal molecular dynamics and accelerated molecular dynamics, respectively) when compared to other complexes. We believe that the degree of unsaturation of the hydrocarbon chain in the lipid molecules may impact on the overall conformational behavior, interaction mode and encapsulation (wrapping) of the lipid molecules around the vancomycin molecule. This thorough computational analysis prior to the experimental investigation is a valuable approach to guide for predicting the encapsulation

The Role of ATP-Binding Cassette Transporters in Neuro-Inflammation: Relevance for Bioactive Lipids

OpenAIRE

Kooij, Gijs; van Horssen, Jack; Bandaru, Veera Venkata Ratnam; Haughey, Norman J.; de Vries, Helga E.

2012-01-01

ATP-binding cassette (ABC) transporters are highly expressed by brain endothelial cells that form the blood-brain barrier (BBB). These efflux pumps play an important role in maintaining brain homeostasis as they actively hinder the entry of unwanted blood-derived compounds into the central nervous system (CNS). Consequently, their high activity at the BBB has been a major hurdle for the treatment of several brain diseases, as they prevent numerous drugs to reach their site of action within th...

Species differences in [11C]clorgyline binding in brain

International Nuclear Information System (INIS)

Fowler, Joanna S.; Ding, Yu-Shin; Logan, Jean; MacGregor, Robert R.; Shea, Colleen; Garza, Victor; Gimi, Raomond; Volkow, Nora D.; Wang, Gene-Jack; Schlyer, David; Ferrieri, Richard; Gatley, S. John; Alexoff, David; Carter, Pauline; King, Payton; Pappas, Naomi; Arnett, Carroll D.

2001-01-01

[ 11 C]Clorgyline selectively binds to MAO A in the human brain. This contrasts with a recent report that [ 11 C]clorgyline (in contrast to other labeled MAO A inhibitors) is not retained in the rhesus monkey brain . To explore this difference, we compared [ 11 C]clorgyline in the baboon brain before and after clorgyline pretreatment and we also synthesized deuterium substituted [ 11 C]clorgyline (and its nor-precursor) for comparison. [ 11 C]Clorgyline was not retained in the baboon brain nor was it influenced by clorgyline pretreatment or by deuterium substitution, contrasting to results in humans. This suggests a species difference in the susceptibility of MAO A to inhibition by clorgyline and represents an unusual example of where the behavior of a radiotracer in the baboon brain does not predict its behavior in the human brain

Implications of formulation design on lipid-based nanostructured carrier system for drug delivery to brain.

Science.gov (United States)

Salunkhe, Sachin S; Bhatia, Neela M; Bhatia, Manish S

2016-05-01

The aim of present investigation was to formulate and develop lipid-based nanostructured carriers (NLCs) containing Idebenone (IDE) for delivery to brain. Attempts have been made to evaluate IDE NLCs for its pharmacokinetic and pharmacodynamic profile through the objective of enhancement in bioavailability and effectivity of drug. Nanoprecipitation technique was used for development of drug loaded NLCs. The components solid lipid Precirol ATO 5, oil Miglyol 840, surfactants Tween 80 and Labrasol have been screened out for formulation development by consideration of preformulation parameters including solubility, Required Hydrophilic lipophilic balance (HLB) of lipids and stability study. Developed IDE NLCs were subjected for particle size, zeta potential, entrapment efficiency (%EE), crystallographic investigation, transmission electron microscopy, in vitro drug release, pharmacokinetics, in vivo and stability study. Formulation under investigation has particle size 174.1 ± 2.6 nm, zeta potential -18.65 ± 1.13 mV and% EE 90.68 ± 2.90. Crystallographic studies exemplified for partial amorphization of IDE by molecularly dispersion within lipid crust. IDE NLCs showed drug release 93.56 ± 0.39% at end of 24 h by following Higuchi model which necessitates for appropriate drug delivery with enhancement in bioavailability of drug by 4.6-fold in plasma and 2.8-fold in brain over plain drug loaded aqueous dispersions. In vivo studies revealed that effect of drug was enhanced by prepared lipid nanocarriers. IDE lipid-based nanostructured carriers could have potential for efficient drug delivery to brain with enhancement in bioavailability of drug over the conventional formulations.

Sex Differences in Serotonin 1 Receptor Binding in Rat Brain

Science.gov (United States)

Fischette, Christine T.; Biegon, Anat; McEwen, Bruce S.

1983-10-01

Male and female rats exhibit sex differences in binding by serotonin 1 receptors in discrete areas of the brain, some of which have been implicated in the control of ovulation and of gonadotropin release. The sex-specific changes in binding, which occur in response to the same hormonal (estrogenic) stimulus, are due to changes in the number of binding sites. Castration alone also affects the number of binding sites in certain areas. The results lead to the conclusion that peripheral hormones modulate binding by serotonin 1 receptors. The status of the serotonin receptor system may affect the reproductive capacity of an organism and may be related to sex-linked emotional disturbances in humans.

(+)- and (-)-N-allylnormetazocine binding sites in mouse brain: in vitro and in vivo characterization and regional distribution

International Nuclear Information System (INIS)

Compton, D.R.; Bagley, R.B.; Katzen, J.S.; Martin, B.R.

1987-01-01

In vivo and in vitro binding studies, both in whole brain and in selected areas, indicate that non-identical (+)- and (-)-NANM sites exist in the mouse brain, and each exhibits a different regional distribution. The in vivo binding of (+)- 3 H-NANM was found to be saturable at pharmacologically relevant doses, and represents a relatively small (10 - 22%) portion of total brain (+)- 3 H-NANM concentrations. The in vivo binding of (+)- 3 H-NANM was selectively displaced by (+)-NANM and PCP, and more sensitive to haloperidol and (+)-ketocyclazocine than the (-)- 3 H-NANM site. The in vivo binding of (-)- 3 H-NANM was selectively displaced by (-)-NANM, and more sensitive to naloxone and (-) ketocyclazocine than the (+)- 3 H-NANM site, and insensitive to PCP. This study indicates that the investigation of NANM binding sites is possible using in vivo binding techniques, and that each isomer apparently binds, in the mouse brain, to a single class of distinct sites. 32 references, 4 figures, 2 tables

Opiate receptor binding in the brain of the seizure sensitive Mongolian gerbil (Meriones unguiculatus).

Science.gov (United States)

Lee, R J; Olsen, R W; Lomax, P; McCabe, R T; Wamsley, J K

1984-12-01

Opiate receptor binding was studied in seizure sensitive (SS) and seizure resistant (SR) strains of the Mongolian gerbil. Cryostat sections of the brain were labeled with [3H]-dihydromorphine, subjected to autoradiography and analysed by microdensitometry. SS gerbils, prior to seizure induction, demonstrated overall greater brain opiate binding when compared to SR animals. Immediately following a seizure, binding in the interpeduncular nucleus fell to levels found in SR animals. The increased opiate binding in the SS (pre-seizure) compared to SR gerbils could reflect a deficit of endogenous ligand which could underlie the seizure diathesis in the gerbil.

Insulin Regulates Hepatic Triglyceride Secretion and Lipid Content via Signaling in the Brain.

Science.gov (United States)

Scherer, Thomas; Lindtner, Claudia; O'Hare, James; Hackl, Martina; Zielinski, Elizabeth; Freudenthaler, Angelika; Baumgartner-Parzer, Sabina; Tödter, Klaus; Heeren, Joerg; Krššák, Martin; Scheja, Ludger; Fürnsinn, Clemens; Buettner, Christoph

2016-06-01

Hepatic steatosis is common in obesity and insulin resistance and results from a net retention of lipids in the liver. A key mechanism to prevent steatosis is to increase secretion of triglycerides (TG) packaged as VLDLs. Insulin controls nutrient partitioning via signaling through its cognate receptor in peripheral target organs such as liver, muscle, and adipose tissue and via signaling in the central nervous system (CNS) to orchestrate organ cross talk. While hepatic insulin signaling is known to suppress VLDL production from the liver, it is unknown whether brain insulin signaling independently regulates hepatic VLDL secretion. Here, we show that in conscious, unrestrained male Sprague Dawley rats the infusion of insulin into the third ventricle acutely increased hepatic TG secretion. Chronic infusion of insulin into the CNS via osmotic minipumps reduced the hepatic lipid content as assessed by noninvasive (1)H-MRS and lipid profiling independent of changes in hepatic de novo lipogenesis and food intake. In mice that lack the insulin receptor in the brain, hepatic TG secretion was reduced compared with wild-type littermate controls. These studies identify brain insulin as an important permissive factor in hepatic VLDL secretion that protects against hepatic steatosis. © 2016 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

Potent and Selective BACE-1 Peptide Inhibitors Lower Brain Aβ Levels Mediated by Brain Shuttle Transport

Directory of Open Access Journals (Sweden)

Nadine Ruderisch

2017-10-01

Full Text Available Therapeutic approaches to fight Alzheimer's disease include anti-Amyloidβ (Aβ antibodies and secretase inhibitors. However, the blood-brain barrier (BBB limits the brain exposure of biologics and the chemical space for small molecules to be BBB permeable. The Brain Shuttle (BS technology is capable of shuttling large molecules into the brain. This allows for new types of therapeutic modalities engineered for optimal efficacy on the molecular target in the brain independent of brain penetrating properties. To this end, we designed BACE1 peptide inhibitors with varying lipid modifications with single-digit picomolar cellular potency. Secondly, we generated active-exosite peptides with structurally confirmed dual binding mode and improved potency. When fused to the BS via sortase coupling, these BACE1 inhibitors significantly reduced brain Aβ levels in mice after intravenous administration. In plasma, both BS and non-BS BACE1 inhibitor peptides induced a significant time- and dose-dependent decrease of Aβ. Our results demonstrate that the BS is essential for BACE1 peptide inhibitors to be efficacious in the brain and active-exosite design of BACE1 peptide inhibitors together with lipid modification may be of therapeutic relevance.

Lipid vesicle-mediated affinity chromatography using magnetic activated cell sorting (LIMACS): a novel method to analyze protein-lipid interaction.

Science.gov (United States)

Bieberich, Erhard

2011-04-26

The analysis of lipid protein interaction is difficult because lipids are embedded in cell membranes and therefore, inaccessible to most purification procedures. As an alternative, lipids can be coated on flat surfaces as used for lipid ELISA and Plasmon resonance spectroscopy. However, surface coating lipids do not form microdomain structures, which may be important for the lipid binding properties. Further, these methods do not allow for the purification of larger amounts of proteins binding to their target lipids. To overcome these limitations of testing lipid protein interaction and to purify lipid binding proteins we developed a novel method termed lipid vesicle-mediated affinity chromatography using magnetic-activated cell sorting (LIMACS). In this method, lipid vesicles are prepared with the target lipid and phosphatidylserine as the anchor lipid for Annexin V MACS. Phosphatidylserine is a ubiquitous cell membrane phospholipid that shows high affinity to the protein Annexin V. Using magnetic beads conjugated to Annexin V the phosphatidylserine-containing lipid vesicles will bind to the magnetic beads. When the lipid vesicles are incubated with a cell lysate the protein binding to the target lipid will also be bound to the beads and can be co-purified using MACS. This method can also be used to test if recombinant proteins reconstitute a protein complex binding to the target lipid. We have used this method to show the interaction of atypical PKC (aPKC) with the sphingolipid ceramide and to co-purify prostate apoptosis response 4 (PAR-4), a protein binding to ceramide-associated aPKC. We have also used this method for the reconstitution of a ceramide-associated complex of recombinant aPKC with the cell polarity-related proteins Par6 and Cdc42. Since lipid vesicles can be prepared with a variety of sphingo- or phospholipids, LIMACS offers a versatile test for lipid-protein interaction in a lipid environment that resembles closely that of the cell membrane

A calorimetric study of the thermotropic behaviour of mixtures of brain cerebrosides with other brain lipids.

Science.gov (United States)

Johnston, D S; Chapman, D

1988-04-22

We have used a computer-controlled differential scanning calorimeter to determine the phases present in mixtures of the brain galactocerebrosides with other representative brain lipids. There are two types of brain galactocerebroside, those which possess an alpha-hydroxy substituent on the acyl chain (HFA) and those that do not (NFA). In the liquid crystalline state both cerebrosides were miscible with all the lipids studied, but in the gel state they were immiscible with cholesterol and the brain phosphatidylcholines. However, cholesterol mixtures in which the cholesterol mole fraction exceeded one third formed homogeneous metastable gel states on cooling from above the melting point of the cerebroside. Relaxation to the stable two phase state took place slowly over several hours. The solubilities of the galactocerebrosides in the other main brain sphingolipid, sphingomyelin, were much higher. Only in the case of the NFA galactocerebroside and at low mole fractions of sphingomyelin was immiscibility detected. Ternary mixtures of the two cerebrosides with sphingomyelin/cholesterol and phosphatidylcholine/cholesterol (PC/Chol) showed different miscibility characteristics. On cooling from 80 degrees C all mixtures formed homogeneous gel states. However, on standing the cerebrosides separated into discrete gel phases in all mixtures but one, that in which HFA galactocerebrosides were mixed with sphingomyelin and cholesterol. The cerebroside in the mixture with the composition closest to that of myelin, HFA/PC/Chol, melted at 38 degrees C. On scanning guinea pig CNS myelin which had been equilibrated at 5 degrees C a transition was detected with Tmax 33 degrees C. On the basis of comparison with the HFA/PC/Chol mixture we propose that the transition in myelin at this temperature is due to the melting of a galactocerebroside gel phase.

Small substrate transport and mechanism of a molybdate ATP binding cassette transporter in a lipid environment.

Science.gov (United States)

Rice, Austin J; Harrison, Alistair; Alvarez, Frances J D; Davidson, Amy L; Pinkett, Heather W

2014-05-23

Embedded in the plasma membrane of all bacteria, ATP binding cassette (ABC) importers facilitate the uptake of several vital nutrients and cofactors. The ABC transporter, MolBC-A, imports molybdate by passing substrate from the binding protein MolA to a membrane-spanning translocation pathway of MolB. To understand the mechanism of transport in the biological membrane as a whole, the effects of the lipid bilayer on transport needed to be addressed. Continuous wave-electron paramagnetic resonance and in vivo molybdate uptake studies were used to test the impact of the lipid environment on the mechanism and function of MolBC-A. Working with the bacterium Haemophilus influenzae, we found that MolBC-A functions as a low affinity molybdate transporter in its native environment. In periods of high extracellular molybdate concentration, H. influenzae makes use of parallel molybdate transport systems (MolBC-A and ModBC-A) to take up a greater amount of molybdate than a strain with ModBC-A alone. In addition, the movement of the translocation pathway in response to nucleotide binding and hydrolysis in a lipid environment is conserved when compared with in-detergent analysis. However, electron paramagnetic resonance spectroscopy indicates that a lipid environment restricts the flexibility of the MolBC translocation pathway. By combining continuous wave-electron paramagnetic resonance spectroscopy and substrate uptake studies, we reveal details of molybdate transport and the logistics of uptake systems that employ multiple transporters for the same substrate, offering insight into the mechanisms of nutrient uptake in bacteria. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

Aging-induced changes in brain regional serotonin receptor binding: Effect of Carnosine.

Science.gov (United States)

Banerjee, S; Poddar, M K

2016-04-05

Monoamine neurotransmitter, serotonin (5-HT) has its own specific receptors in both pre- and post-synapse. In the present study the role of carnosine on aging-induced changes of [(3)H]-5-HT receptor binding in different brain regions in a rat model was studied. The results showed that during aging (18 and 24 months) the [(3)H]-5-HT receptor binding was reduced in hippocampus, hypothalamus and pons-medulla with a decrease in their both Bmax and KD but in cerebral cortex the [(3)H]-5-HT binding was increased with the increase of its only Bmax. The aging-induced changes in [(3)H]-5-HT receptor binding with carnosine (2.0 μg/kg/day, intrathecally, for 21 consecutive days) attenuated in (a) 24-month-aged rats irrespective of the brain regions with the attenuation of its Bmax except hypothalamus where both Bmax and KD were significantly attenuated, (b) hippocampus and hypothalamus of 18-month-aged rats with the attenuation of its Bmax, and restored toward the [(3)H]-5-HT receptor binding that observed in 4-month-young rats. The decrease in pons-medullary [(3)H]-5-HT binding including its Bmax of 18-month-aged rats was promoted with carnosine without any significant change in its cerebral cortex. The [(3)H]-5-HT receptor binding with the same dosages of carnosine in 4-month-young rats (a) increased in the cerebral cortex and hippocampus with the increase in their only Bmax whereas (b) decreased in hypothalamus and pons-medulla with a decrease in their both Bmax and KD. These results suggest that carnosine treatment may (a) play a preventive role in aging-induced brain region-specific changes in serotonergic activity (b) not be worthy in 4-month-young rats in relation to the brain regional serotonergic activity. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

Selective binding of 2-[125I]iodo-nisoxetine to norepinephrine transporters in the brain

International Nuclear Information System (INIS)

Kung, M.-P.; Choi, Seok-Rye; Hou, Catherine; Zhuang, Z.-P.; Foulon, Catherine; Kung, Hank F.

2004-01-01

A radioiodinated ligand, (R)-N-methyl-(2-[ 125 I]iodo-phenoxy)-3-phenylpropylamine, [ 125 I]2-INXT, targeting norepinephrine transporters (NET), was successfully prepared. A no-carrier-added product, [ 125 I]2-INXT, displayed a saturable binding with a high affinity (K d =0.06 nM) in the homogenates prepared from rat cortical tissues as well as from LLC-PK 1 cells expressing NET. A relatively low number of binding sties (B max =55 fmol/mg protein) measured with [ 125 I]2-INXT in rat cortical homogenates is consistent with the value reported for a known NET ligand, [ 3 H]nisoxetine. Competition studies with various compounds on [ 125 I]2-INXT binding clearly confirmed the pharmacological specificity and selectivity for NET binding sites. Following a tail-vein injection of [ 125 I]2-INXT in rats, a good initial brain uptake was observed (0.56% dose at 2 min) followed by a slow washout from the brain (0.2% remained at 3 hours post-injection). The hypothalamus (a NET-rich region) to striatum (a region devoid of NET) ratio was 1.5 at 3 hours post-i.v. injection. Pretreatment of rats with nisoxetine significantly inhibited the uptake of [ 125 I]2-INXT (70-100% inhibition) in locus coeruleus, hypothalamus and raphe nuclei, regions known to have a high density of NET; whereas escitalopram, a serotonin transporter ligand, did not show a similar effect. Ex vivo autoradiography of rat brain sections of [ 125 I]2-INXT (at 3 hours after an i.v. injection) displayed an excellent regional brain localization pattern corroborated to the specific NET distribution in the brain. The specific brain localization was significantly reduced by a dose of nisoxetine pretreatment. Taken together, the data suggest that [ 123 I]2-INXT may be useful for mapping NET binding sites in the brain

SAXS Study of Sterically Stabilized Lipid Nanocarriers Functionalized by DNA

Science.gov (United States)

Angelov, Borislav; Angelova, Angelina; Filippov, Sergey; Karlsson, Göran; Terrill, Nick; Lesieur, Sylviane; Štěpánek, Petr

2012-03-01

The structure of novel spontaneously self-assembled plasmid DNA/lipid complexes is investigated by means of synchrotron radiation small-angle X-ray scattering (SAXS) and Cryo-TEM imaging. Liquid crystalline (LC) hydrated lipid systems are prepared using the non-ionic lipids monoolein and DOPE-PEG2000 and the cationic amphiphile CTAB. The employed plasmid DNA (pDNA) is encoding for the human protein brain-derived neurotrophic factor (BDNF). A coexistence of nanoparticulate objects with different LC inner organizations is established. A transition from bicontinuous membrane sponges, cubosome intermediates and unilamelar liposomes to multilamellar vesicles, functionalized by pDNA, is favoured upon binding and compaction of pBDNF onto the cationic PEGylated lipid nanocarriers. The obtained sterically stabilized multicompartment nanoobjects, with confined supercoiled plasmid DNA (pBDNF), are important in the context of multicompartment lipid nanocarriers of interest for gene therapy of neurodegenerative diseases.

SAXS Study of Sterically Stabilized Lipid Nanocarriers Functionalized by DNA

International Nuclear Information System (INIS)

Angelov, Borislav; Filippov, Sergey; Štepánek, Petr; Angelova, Angelina; Lesieur, Sylviane; Karlsson, Göran; Terrill, Nick

2012-01-01

The structure of novel spontaneously self-assembled plasmid DNA/lipid complexes is investigated by means of synchrotron radiation small-angle X-ray scattering (SAXS) and Cryo-TEM imaging. Liquid crystalline (LC) hydrated lipid systems are prepared using the non-ionic lipids monoolein and DOPE-PEG 2000 and the cationic amphiphile CTAB. The employed plasmid DNA (pDNA) is encoding for the human protein brain-derived neurotrophic factor (BDNF). A coexistence of nanoparticulate objects with different LC inner organizations is established. A transition from bicontinuous membrane sponges, cubosome intermediates and unilamelar liposomes to multilamellar vesicles, functionalized by pDNA, is favoured upon binding and compaction of pBDNF onto the cationic PEGylated lipid nanocarriers. The obtained sterically stabilized multicompartment nanoobjects, with confined supercoiled plasmid DNA (pBDNF), are important in the context of multicompartment lipid nanocarriers of interest for gene therapy of neurodegenerative diseases.

Low 5-HT1B receptor binding in the migraine brain

DEFF Research Database (Denmark)

Deen, Marie; Hansen, Hanne D; Hougaard, Anders

2018-01-01

Background The pathophysiology of migraine may involve dysfunction of serotonergic signaling. In particular, the 5-HT1B receptor is considered a key player due to the efficacy of 5-HT1B receptor agonists for treatment of migraine attacks. Aim To examine the cerebral 5-HT1B receptor binding....... Patients who reported migraine brain regions involved in pain modulation as regions of interest and applied a latent variable model (LVM) to assess the group effect on binding across these regions. Results Our data...... support a model wherein group status predicts the latent variable ( p = 0.038), with migraine patients having lower 5-HT1B receptor binding across regions compared to controls. Further, in a whole-brain voxel-based analysis, time since last migraine attack correlated positively with 5-HT1B receptor...

Cholesterol is necessary both for the toxic effect of Abeta peptides on vascular smooth muscle cells and for Abeta binding to vascular smooth muscle cell membranes.

Science.gov (United States)

Subasinghe, Supundi; Unabia, Sharon; Barrow, Colin J; Mok, Su San; Aguilar, Marie-Isabel; Small, David H

2003-02-01

Accumulation of beta amyloid (Abeta) in the brain is central to the pathogenesis of Alzheimer's disease. Abeta can bind to membrane lipids and this binding may have detrimental effects on cell function. In this study, surface plasmon resonance technology was used to study Abeta binding to membranes. Abeta peptides bound to synthetic lipid mixtures and to an intact plasma membrane preparation isolated from vascular smooth muscle cells. Abeta peptides were also toxic to vascular smooth muscle cells. There was a good correlation between the toxic effect of Abeta peptides and their membrane binding. 'Ageing' the Abeta peptides by incubation for 5 days increased the proportion of oligomeric species, and also increased toxicity and the amount of binding to lipids. The toxicities of various Abeta analogs correlated with their lipid binding. Significantly, binding was influenced by the concentration of cholesterol in the lipid mixture. Reduction of cholesterol in vascular smooth muscle cells not only reduced the binding of Abeta to purified plasma membrane preparations but also reduced Abeta toxicity. The results support the view that Abeta toxicity is a direct consequence of binding to lipids in the membrane. Reduction of membrane cholesterol using cholesterol-lowering drugs may be of therapeutic benefit because it reduces Abeta-membrane binding.

Brain serotonin and dopamine transporter bindings in adults with high-functioning autism.

Science.gov (United States)

Nakamura, Kazuhiko; Sekine, Yoshimoto; Ouchi, Yasuomi; Tsujii, Masatsugu; Yoshikawa, Etsuji; Futatsubashi, Masami; Tsuchiya, Kenji J; Sugihara, Genichi; Iwata, Yasuhide; Suzuki, Katsuaki; Matsuzaki, Hideo; Suda, Shiro; Sugiyama, Toshiro; Takei, Nori; Mori, Norio

2010-01-01

Autism is a neurodevelopmental disorder that is characterized by repetitive and/or obsessive interests and behavior and by deficits in sociability and communication. Although its neurobiological underpinnings are postulated to lie in abnormalities of the serotoninergic and dopaminergic systems, the details remain unknown. To determine the occurrence of changes in the binding of serotonin and dopamine transporters, which are highly selective markers for their respective neuronal systems. Using positron emission tomography, we measured the binding of brain serotonin and dopamine transporters in each individual with the radioligands carbon 11 ((11)C)-labeled trans-1,2,3,5,6,10-beta-hexahydro-6-[4-(methylthio)phenyl]pyrrolo-[2,1-a]isoquinoline ([(11)C](+)McN-5652) and 2beta-carbomethoxy-3-beta-(4-fluorophenyl)tropane ([(11)C]WIN-35,428), respectively. Statistical parametric mapping was used for between-subject analysis and within-subject correlation analysis with respect to clinical variables. Participants recruited from the community. Twenty men (age range, 18-26 years; mean [SD] IQ, 99.3 [18.1]) with autism and 20 age- and IQ-matched control subjects. Serotonin transporter binding was significantly lower throughout the brain in autistic individuals compared with controls (P dopamine transporter binding was significantly higher in the orbitofrontal cortex of the autistic group (P dopamine transporter binding was significantly inversely correlated with serotonin transporter binding (r = -0.61; P = .004). The brains of autistic individuals have abnormalities in both serotonin transporter and dopamine transporter binding. The present findings indicate that the gross abnormalities in these neurotransmitter systems may underpin the neurophysiologic mechanism of autism. Our sample was not characteristic or representative of a typical sample of adults with autism in the community.

Characterization of the binding of the Ptychodiscus brevis neurotoxin T17 to sodium channels in rat brain synaptosomes

International Nuclear Information System (INIS)

Poli, M.A.

1985-01-01

The lipid-soluble polyether neurotoxins isolated from the marine dinoflagellate Ptychodiscus brevis (formerly Gymnodinium breve) have been determined to bind to a unique receptor site associated with the voltage-sensitive sodium channel in rat brain synaptosomes. Reduction of the C 42 aldehyde function of T34 to the alcohol function of T17 using NaB 3 H 4 yielded 3 H-T17 with a specific activity of 15 Ci;/mmol. Using this specific probe, binding to sodium channels was measured at 4 0 CC, 22 0 C, and 37 0 C. Rosenthal analysis of the binding data yielded a K/sub d/ of 2.9 nM and B/sub max/ of 6.8 pmoles 3 H-T17 per mg of synaptosomal protein at 4 0 C. Both K/sub d/ and B/sub max/ were found to be temperature dependent. Depolarization of the synaptosomes by osmotic lysis resulted in the loss of 34% of the available receptor sites, with no decrease in binding affinity. Unlabeled T17, T34, and synthetic T17 (reduced T34) were equipotent in their ability to displace 3 H-T17 from its specific receptor site. Competition experiments using natural toxin probes specific for sites I-IV on the voltage-sensitive sodium channel demonstrate that 3 H-T17 does not bind to any of the previously-described neurotoxin receptor sites. A fifth site is proposed

Characterization of the binding of the Ptychodiscus brevis neurotoxin T17 to sodium channels in rat brain synaptosomes

Energy Technology Data Exchange (ETDEWEB)

Poli, M.A.

1985-01-01

The lipid-soluble polyether neurotoxins isolated from the marine dinoflagellate Ptychodiscus brevis (formerly Gymnodinium breve) have been determined to bind to a unique receptor site associated with the voltage-sensitive sodium channel in rat brain synaptosomes. Reduction of the C/sub 42/ aldehyde function of T34 to the alcohol function of T17 using NaB/sup 3/H/sub 4/ yielded /sup 3/H-T17 with a specific activity of 15 Ci;/mmol. Using this specific probe, binding to sodium channels was measured at 4/sup 0/CC, 22/sup 0/C, and 37/sup 0/C. Rosenthal analysis of the binding data yielded a K/sub d/ of 2.9 nM and B/sub max/ of 6.8 pmoles /sup 3/H-T17 per mg of synaptosomal protein at 4/sup 0/C. Both K/sub d/ and B/sub max/ were found to be temperature dependent. Depolarization of the synaptosomes by osmotic lysis resulted in the loss of 34% of the available receptor sites, with no decrease in binding affinity. Unlabeled T17, T34, and synthetic T17 (reduced T34) were equipotent in their ability to displace /sup 3/H-T17 from its specific receptor site. Competition experiments using natural toxin probes specific for sites I-IV on the voltage-sensitive sodium channel demonstrate that /sup 3/H-T17 does not bind to any of the previously-described neurotoxin receptor sites. A fifth site is proposed.

Nanoscale orientation and lateral organization of chimeric metal-binding green fluorescent protein on lipid membrane determined by epifluorescence and atomic force microscopy

International Nuclear Information System (INIS)

Prachayasittikul, Virapong; Isarankura Na Ayudhya, Chartchalerm; Tantimongcolwat, Tanawut; Galla, Hans-Joachim

2005-01-01

Epifluorescence microscopy as well as atomic force microscopy was successfully applied to explore the orientation and lateral organization of a group of chimeric green fluorescent proteins (GFPs) on lipid membrane. Incorporation of the chimeric GFP carrying Cd-binding region (His6CdBP4GFP) to the fluid phase of DPPC monolayer resulted in a strong fluorescence intensity at the air-water interface. Meanwhile, non-specific adsorption of the GFP having hexahistidine (His6GFP) led to the perturbation of the protein structure in which very low fluorescence was observed. Specific binding of both of the chimeric GFPs to immobilized zinc ions underneath the metal-chelating lipid membrane was revealed. This specific binding could be reversibly controlled by addition of metal ions or metal chelator. Binding of the chimeric GFPs to the metal-chelating lipid membrane was proven to be the end-on orientation while the side-on adsorption was contrarily noted in the absence of metal ions. Increase of lateral mobility owing to the fluidization effect on the chelating lipid membrane subsequently facilitated crystal formation. All these findings have opened up a potential approach for a specific orientation of immobilization of protein at the membrane interface. This could have accounted for a better opportunity of sensor development

Characterization of [125I]omega-conotoxin binding to brain N calcium channels and (-)[3H] desmethoxyverapamil binding to novel calcium channels in osteoblast-like osteosarcoma cells

International Nuclear Information System (INIS)

Wagner, J.A.

1987-01-01

This dissertation provides molecular evidence for a diversity of Ca 2+ channels in neuronal and non-neuronal tissues. First, I demonstrated specific, reversible, saturable binding sites for omega [ 125 I]conotoxin GVIA (omega[ 125 I]CTX) in rat brain and rabbit sympathetic ganglion. Omega [ 125 I]CTX binding has a unique pharmacology, ion selectivity, and anatomical distribution in rat brain. Omega [ 125 I]CTX binding was solubilized, retaining an appropriate pharmacology and ion selectivity. Omega[ 125 I]CTX binding may be associated with a Ca 2+ channel because the K/sub D/ of omega [ 125 I]CTX is similar to the IC 50 of inhibition of depolarization-induced 45 Ca 2+ flux into rat brain synaptosomes. Specific (-)[ 3 H]desmethoxyverapamil ((-)[ 3 H]DMV) binding sites were demonstrated on osteoblast-like osteosarcoma cell membranes

Binding of kappa- and sigma-opiates in rat brain

International Nuclear Information System (INIS)

Wolozin, B.L.; Nishimura, S.; Pasternak, G.W.

1982-01-01

Detailed displacements of [ 3 H]dihydromorphine by ketocyclazocine and SKF 10,047, [ 3 H]ethylketocyclazocine by SKF 10,047, and [ 3 H]SKF 10,047 by ketocyclazocine are all multiphasic, suggesting multiple binding sites. After treating brain tissue in vitro with naloxazone, all displacements lose the initial inhibition of 3 H-ligand binding by low concentrations of unlabeled drugs. Together with Scatchard analysis of saturation experiments, these studies suggest a common site which binds mu-, kappa, and sigma-opiates and enkephalins equally well and with highest affinity (KD less than 1 nM). The ability of unlabeled drugs to displace the low affinity binding of [ 3 H]dihydromorphine (KD . 3 nM), [ 3 H]ethylketocyclazocine (KD . 4 nM), [ 3 H]SKF 10,047 (KD . 6 nM), and D-Ala2-D-Leu5-[ 3 H]enkephalin (KD . 5 nM) remaining after treating tissue with naloxazone demonstrates unique pharmacological profiles for each. These results suggest the existence of distinct binding sites for kappa- and sigma-opiates which differ from those sites which selectively bind morphine (mu) and enkephalin

[3H]-beta-endorphin binding in rat brain

International Nuclear Information System (INIS)

Houghten, R.A.; Johnson, N.; Pasternak, G.W.

1984-01-01

The binding of [ 3 H]-beta-endorphin to rat brain homogenates is complex. Although Scatchard analysis of saturation studies yields a straight line, detailed competition studies are multiphasic, suggesting that even at low concentrations of the compound, the 3 H-ligand is binding to more than one class of site. A portion of [ 3 H]-beta-endorphin binding is sensitive to low concentrations of morphine or D-Ala2-Leu5-enkephalin (less than 5 nM). The inhibition observed with each compound alone (5 nM) is the same as that seen with both together (each at 5 nM). Thus, the binding remaining in the presence of both morphine and the enkephalin does not correspond to either mu or delta sites. The portion of [ 3 H]-beta-endorphin binding that is inhibited under these conditions appears to be equally sensitive to both morphine and the enkephalin and may correspond to mu1 sites. Treating membrane homogenates with naloxonazine, a mu1 selective antagonist, lowers [ 3 H]-beta-endorphin binding to the same degree as morphine and D-Ala2-Leu5-enkephalin alone or together. This possible binding of [ 3 H]-beta-endorphin to mu1 sites is consistent with the role of mu1 sites in beta-endorphin analgesia and catalepsy in vivo

Characterization and localization of 3H-arginine8-vasopressin binding to rat kidney and brain tissue

International Nuclear Information System (INIS)

Dorsa, D.M.; Majumdar, L.A.; Petracca, F.M.; Baskin, D.G.; Cornett, L.E.

1983-01-01

Anatomic, behavioral and pharmacologic evidence suggests that arginine8-vasopressin (AVP) serves as a CNS neurotransmitter or neuromodulator. AVP binding to membrane and tissue slice preparations from brain and kidney was characterized, and the anatomical distribution of these binding sites was examined. Conditions for the binding assay were optimized using kidney medullary tissue. Binding of 3 H-AVP (S.A. . 30-51 Ci/mmol, NEN) to brain and kidney membranes and tissue slices was saturable, temperature dependent, linearly related to protein concentration (or number of tissue slices), reversible, and specific since the ability of cold AVP to displace 3 H-AVP from binding was greater than oxytocin and other related peptide fragments. Autoradiographic localization of 3 H-AVP binding was restricted to kidney medullary tissue. In brain tissue, 3 H-AVP binding was found to occur in concentrated foci. Brainstem areas such as the nucleus tractus solitarius (NTS) showed a high density of AVP binding sites. Since local injections of AVP into the NTS have been shown to influence blood pressure, the present study presents the first anatomical evidence for the presence of AVP specific binding sites which might mediate this effect

Semisynthetic Lipopeptides Derived from Nisin Display Antibacterial Activity and Lipid II Binding on Par with That of the Parent Compound

NARCIS (Netherlands)

Koopmans, Timo; Wood, Thomas M.; 't Hart, Peter; Kleijn, Laurens H. J.; Hendrickx, Antoni P. A.; Willems, Rob J. L.; Breukink, Eefjan; Martin, Nathaniel I.

2015-01-01

The lipid II-binding N-terminus of nisin, comprising the so-called A/B ring system, was synthetically modified to provide antibacterially active and proteolytically stable derivatives. A variety of lipids were coupled to the C-terminus of the nisin A/B ring system to generate semisynthetic

Effect of dietary poly unsaturated fatty acids on total brain lipid concentration and anxiety levels of electron beam irradiated mice

International Nuclear Information System (INIS)

Suchetha Kumari; Bekal, Mahesh

2013-01-01

The whole brain irradiation causes injury to the nervous system at various levels. Omega-3 poly unsaturated fatty acids are very much essential for the growth and development of nervous system. Dietary supplementation of these nutrients will promote the development of injured neuronal cells. Therefore this study was undertaken to establish the role of Omega-3 poly unsaturated fatty acids on total brain lipid concentration, lipid peroxidation and anxiety levels in the irradiated mice. The effect of Electron Beam Radiation (EBR) on total brain lipid concentration, lipid peroxidation and anxiety level were investigated in male Swiss albino mice. The study groups were subjected to a sub-lethal dose of EBR and also the flax seed extract and fish oil were given orally to the irradiated mice. Irradiated groups show significant elevation in anxiety levels when compared to control group, indicating the acute radiation effects on the central nervous system. But the oral supplementation of dietary PUFA source decrees the anxiety level in the irradiated group. The analysis of lipid peroxidation showed a significant level of changes when compared between control and radiation groups. Dietary PUFA supplementation showed a significant level of decrease in the lipid peroxidation in the irradiated groups. The observation of total lipids in brain shows decrease in concentration in the irradiated groups, the differences in the variables follow the similar patterns as of that the MDA levels. This study suggests that the dietary intake of PUFAs may help in prevention and recovery of the oxidative stress caused by radiation. (author)

Species differences in [{sup 11}C]clorgyline binding in brain

Energy Technology Data Exchange (ETDEWEB)

Fowler, Joanna S. E-mail: fowler@bnl.gov; Ding, Yu-Shin; Logan, Jean; MacGregor, Robert R.; Shea, Colleen; Garza, Victor; Gimi, Raomond; Volkow, Nora D.; Wang, Gene-Jack; Schlyer, David; Ferrieri, Richard; Gatley, S. John; Alexoff, David; Carter, Pauline; King, Payton; Pappas, Naomi; Arnett, Carroll D

2001-10-01

[{sup 11}C]Clorgyline selectively binds to MAO A in the human brain. This contrasts with a recent report that [{sup 11}C]clorgyline (in contrast to other labeled MAO A inhibitors) is not retained in the rhesus monkey brain . To explore this difference, we compared [{sup 11}C]clorgyline in the baboon brain before and after clorgyline pretreatment and we also synthesized deuterium substituted [{sup 11}C]clorgyline (and its nor-precursor) for comparison. [{sup 11}C]Clorgyline was not retained in the baboon brain nor was it influenced by clorgyline pretreatment or by deuterium substitution, contrasting to results in humans. This suggests a species difference in the susceptibility of MAO A to inhibition by clorgyline and represents an unusual example of where the behavior of a radiotracer in the baboon brain does not predict its behavior in the human brain.

Oxygen Mapping within Healthy and Acutely Infarcted Brain Tissue in Humans Using the NMR Relaxation of Lipids: A Proof-Of-Concept Translational Study.

Science.gov (United States)

Colliez, Florence; Safronova, Marta M; Magat, Julie; Joudiou, Nicolas; Peeters, André P; Jordan, Bénédicte F; Gallez, Bernard; Duprez, Thierry

2015-01-01

The clinical applicability of brain oxygenation mapping using the MOBILE (Mapping of Oxygen By Imaging Lipids relaxation Enhancement) magnetic resonance (MR) technique was assessed in the clinical setting of normal brain and of acute cerebral ischemia as a founding proof-of-concept translational study. Changes in the oxygenation level within healthy brain tissue can be detected by analyzing the spin-lattice proton relaxation ('Global T1' combining water and lipid protons) because of the paramagnetic properties of molecular oxygen. It was hypothesized that selective measurement of the relaxation of the lipid protons ('Lipids T1') would result in enhanced sensitivity of pO2 mapping because of higher solubility of oxygen in lipids than in water, and this was demonstrated in pre-clinical models using the MOBILE technique. In the present study, 12 healthy volunteers and eight patients with acute (48-72 hours) brain infarction were examined with the same clinical 3T MR system. Both Lipids R1 (R1 = 1/T1) and Global R1 were significantly different in the infarcted area and the contralateral unaffected brain tissue, with a higher statistical significance for Lipids R1 (median difference: 0.408 s-1; pbrain tissue of stroke patients were not significantly different from the R1 values calculated in the brain tissue of healthy volunteers. The main limitations of the present prototypic version of the MOBILE sequence are the long acquisition time (4 min), hampering robustness of data in uncooperative patients, and a 2 mm slice thickness precluding accurate measurements in small infarcts because of partial volume averaging effects.

The comparison of lipid profiling in mouse brain and liver after starvation and a high-fat diet: A medical systems biology approach

NARCIS (Netherlands)

Ginneken, V.J.T. van; Verheij, E.; Hekman, M.; Greef, J. van der; Feskens, E.J.M.; Poelmann, R.E.

2011-01-01

We investigated with LC-MS techniques, measuring approximately 109 lipid compounds, in mouse brain and liver tissue after 48 hours of starvation and a High-Fat Diet if brain and liver lipid composition changed. We measured Cholesterolesters (ChE), Lysophosphatidyl-cholines (LPC), Phosphatidylcholine

Protection against Mitochondrial and Metal Toxicity Depends on Functional Lipid Binding Sites in ATP13A2

Directory of Open Access Journals (Sweden)

Shaun Martin

2016-01-01

Full Text Available The late endo-/lysosomal P-type ATPase ATP13A2 (PARK9 is implicated in Parkinson’s disease (PD and Kufor-Rakeb syndrome, early-onset atypical Parkinsonism. ATP13A2 interacts at the N-terminus with the signaling lipids phosphatidic acid (PA and phosphatidylinositol (3,5 bisphosphate (PI(3,5P2, which modulate ATP13A2 activity under cellular stress conditions. Here, we analyzed stable human SHSY5Y cell lines overexpressing wild-type (WT or ATP13A2 mutants in which three N-terminal lipid binding sites (LBS1–3 were mutated. We explored the regulatory role of LBS1–3 in the cellular protection by ATP13A2 against mitochondrial stress induced by rotenone and found that the LBS2-3 mutants displayed an abrogated protective effect. Moreover, in contrast to WT, the LBS2 and LBS3 mutants responded poorly to pharmacological inhibition of, respectively, PI(3,5P2 and PA formation. We further demonstrate that PA and PI(3,5P2 are also required for the ATP13A2-mediated protection against the toxic metals Mn2+, Zn2+, and Fe3+, suggesting a general lipid-dependent activation mechanism of ATP13A2 in various PD-related stress conditions. Our results indicate that the ATP13A2-mediated protection requires binding of PI(3,5P2 to LBS2 and PA to LBS3. Thus, targeting the N-terminal lipid binding sites of ATP13A2 might offer a therapeutic approach to reduce cellular toxicity of various PD insults including mitochondrial stress.

Single Molecule Kinetics of ENTH Binding to Lipid Membranes

Energy Technology Data Exchange (ETDEWEB)

Rozovsky, Sharon [Univ. of Delaware, Newark, DE (United States); Forstner, Martin B. [Syracuse Univ., NY (United States); Sondermann, Holger [Cornell Univ., Ithaca, NY (United States); Groves, Jay T. [Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2012-04-03

Transient recruitment of proteins to membranes is a fundamental mechanism by which the cell exerts spatial and temporal control over proteins’ localization and interactions. Thus, the specificity and the kinetics of peripheral proteins’ membrane residence are an attribute of their function. In this article, we describe the membrane interactions of the interfacial epsin N-terminal homology (ENTH) domain with its target lipid phosphatidylinositol (4,5)-bisphosphate (PtdIns(4,5)P₂). The direct visualization and quantification of interactions of single ENTH molecules with supported lipid bilayers is achieved using total internal reflection fluorescence microscopy (TIRFM) with a time resolution of 13 ms. This enables the recording of the kinetic behavior of ENTH interacting with membranes with physiologically relevant concentrations of PtdIns(4,5)P₂ despite the low effective binding affinity. Subsequent single fluorophore tracking permits us to build up distributions of residence times and to measure ENTH dissociation rates as a function of membrane composition. In addition, due to the high time resolution, we are able to resolve details of the motion of ENTH associated with a simple, homogeneous membrane. In this case ENTH’s diffusive transport appears to be the result of at least three different diffusion processes.

Autoradiographic localization of (125I-Tyr4)bombesin-binding sites in rat brain

International Nuclear Information System (INIS)

Zarbin, M.A.; Kuhar, M.J.; O'Donohue, T.L.; Wolf, S.S.; Moody, T.W.

1985-01-01

The binding of ( 125 I-Tyr 4 )bombesin to rat brain slices was investigated. Radiolabeled (Tyr 4 )bombesin bound with high affinity (K/sub d/ . 4 nM) to a single class of sites (B/sub max/ . 130 fmol/mg of protein); the ratio of specific to nonspecific binding was 6/1. Also, pharmacology studies indicated that the C-terminal of bombesin was important for the high affinity binding activity. Autoradiographic studies indicated that the ( 125 I-Tyr4)bombesin-binding sites were discretely distributed in certain gray but not white matter regions of rat brain. Highest grain densities were present in the olfactory bulb and tubercle, nucleus accumbens, suprachiasmatic and periventricular nuclei of the hypothalamus, central medial thalamic nucleus, medial amygdaloid nucleus, hippocampus, dentate gyrus, subiculum, nucleus of the solitary tract, and substantia gelatinosa. Moderate grain densities were present in the parietal cortex, deep layers of the neocortex, rhinal cortex, caudate putamen, stria terminalis, locus ceruleus, parabrachial nucleus, and facial nucleus. Low grain densities were present in the globus pallidus, lateral thalamus, and midbrain. Negligible grain densities were present in the cerebellum, corpus callosum, and all regions treated with 1 microM unlabeled bombesin. The discrete regional distribution of binding suggests that endogenous bombesin-like peptides may function as important regulatory agents in certain brain loci

Brain Information Sharing During Visual Short-Term Memory Binding Yields a Memory Biomarker for Familial Alzheimer's Disease.

Science.gov (United States)

Parra, Mario A; Mikulan, Ezequiel; Trujillo, Natalia; Sala, Sergio Della; Lopera, Francisco; Manes, Facundo; Starr, John; Ibanez, Agustin

2017-01-01

Alzheimer's disease (AD) as a disconnection syndrome which disrupts both brain information sharing and memory binding functions. The extent to which these two phenotypic expressions share pathophysiological mechanisms remains unknown. To unveil the electrophysiological correlates of integrative memory impairments in AD towards new memory biomarkers for its prodromal stages. Patients with 100% risk of familial AD (FAD) and healthy controls underwent assessment with the Visual Short-Term Memory binding test (VSTMBT) while we recorded their EEG. We applied a novel brain connectivity method (Weighted Symbolic Mutual Information) to EEG data. Patients showed significant deficits during the VSTMBT. A reduction of brain connectivity was observed during resting as well as during correct VSTM binding, particularly over frontal and posterior regions. An increase of connectivity was found during VSTM binding performance over central regions. While decreased connectivity was found in cases in more advanced stages of FAD, increased brain connectivity appeared in cases in earlier stages. Such altered patterns of task-related connectivity were found in 89% of the assessed patients. VSTM binding in the prodromal stages of FAD are associated to altered patterns of brain connectivity thus confirming the link between integrative memory deficits and impaired brain information sharing in prodromal FAD. While significant loss of brain connectivity seems to be a feature of the advanced stages of FAD increased brain connectivity characterizes its earlier stages. These findings are discussed in the light of recent proposals about the earliest pathophysiological mechanisms of AD and their clinical expression. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Acute iron overload and oxidative stress in brain

International Nuclear Information System (INIS)

Piloni, Natacha E.; Fermandez, Virginia; Videla, Luis A.; Puntarulo, Susana

2013-01-01

An in vivo model in rat was developed by intraperitoneally administration of Fe-dextran to study oxidative stress triggered by Fe-overload in rat brain. Total Fe levels, as well as the labile iron pool (LIP) concentration, in brain from rats subjected to Fe-overload were markedly increased over control values, 6 h after Fe administration. In this in vivo Fe overload model, the ascorbyl (A·)/ascorbate (AH − ) ratio, taken as oxidative stress index, was assessed. The A·/AH − ratio in brain was significantly higher in Fe-dextran group, in relation to values in control rats. Brain lipid peroxidation indexes, thiobarbituric acid reactive substances (TBARS) generation rate and lipid radical (LR·) content detected by Electron Paramagnetic Resonance (EPR), in Fe-dextran supplemented rats were similar to control values. However, values of nuclear factor-kappaB deoxyribonucleic acid (NFκB DNA) binding activity were significantly increased (30%) after 8 h of Fe administration, and catalase (CAT) activity was significantly enhanced (62%) 21 h after Fe administration. Significant enhancements in Fe content in cortex (2.4 fold), hippocampus (1.6 fold) and striatum (2.9 fold), were found at 6 h after Fe administration. CAT activity was significantly increased after 8 h of Fe administration in cortex, hippocampus and striatum (1.4 fold, 86, and 47%, respectively). Fe response in the whole brain seems to lead to enhanced NF-κB DNA binding activity, which may contribute to limit oxygen reactive species-dependent damage by effects on the antioxidant enzyme CAT activity. Moreover, data shown here clearly indicate that even though Fe increased in several isolated brain areas, this parameter was more drastically enhanced in striatum than in cortex and hippocampus. However, comparison among the net increase in LR· generation rate, in different brain areas, showed enhancements in cortex lipid peroxidation, without changes in striatum and hippocampus LR· generation rate after 6

Binding of long-lasting local anesthetics to lipid emulsions.

Science.gov (United States)

Mazoit, Jean-Xavier; Le Guen, Régine; Beloeil, Hélène; Benhamou, Dan

2009-02-01

Rapid infusion of lipid emulsion has been proposed to treat local anesthetic toxicity. The authors wanted to test the buffering properties of two commercially available emulsions made of long- and of long- and medium-chain triglycerides. Using the shake-flask method, the authors measured the solubility and binding of racemic bupivacaine, levobupivacaine, and ropivacaine to diluted Intralipid (Fresenius Kabi, Paris, France) and Medialipide (B-Braun, Boulogne, France). The apparent distribution coefficient expressed as the ratio of mole fraction was 823 +/- 198 and 320 +/- 65 for racemic bupivacaine and levobupivacaine, and ropivacaine, respectively, at 500 mg in the Medialipide/buffer emulsion; and 1,870 +/- 92 and 1,240 +/- 14 for racemic bupivacaine and levobupivacaine, and ropivacaine, respectively, in the Intralipid/buffer emulsion. Decreasing the pH from 7.40 to 7.00 of the Medialipide/buffer emulsion led to a decrease in ratio of molar concentration from 121 +/- 3.8 to 46 +/- 2.8 for bupivacaine, and to a lesser extent from 51 +/- 4.0 to 31 +/- 1.6 for ropivacaine. The capacity of the 1% emulsions was 871 and 2,200 microM for the 1% Medialipide and Intralipid emulsions, respectively. The dissociation constant was 818 and 2,120 microM for racemic bupivacaine and levobupivacaine, and ropivacaine, respectively. Increasing the temperature from 20 to 37 degrees C led to a greater increase in affinity for ropivacaine (55%) than for bupivacaine (27%). When the pH of the buffer was decreased from 7.40 to 7.00, the affinity was decreased by a factor of 1.68, similar for both anesthetics. The solubility of long-acting local anesthetics in lipid emulsions and the high capacity of binding of these emulsions most probably explain their clinical efficacy in case of toxicity. The long-chain triglyceride emulsion Intralipid appears to be about 2.5 times more efficacious than the 50/50 medium-chain/long-chain Medialipide emulsion. Also, because of their higher hydrophobicity

Radioprotection by dipyridamole in the aging mouse. Effects on lipid peroxidation in mouse liver, spleen and brain after whole-body X-ray irradiation

International Nuclear Information System (INIS)

Seino, Noritaka

1995-01-01

To investigate the radioprotective effect of dipyridamole in the aging mouse, the lipid peroxide content in aging mouse liver, spleen and brain irradiated by X-ray were measured both before and after injection of dipyridamole. The lipid peroxide content increased with aging from 2 months old to 16 months old in the mouse liver, spleen and brain. The content of lipid peroxide in the liver and spleen of the aging mouse was significantly increased in 7 days after whole-body irradiation with 8 Gy, but was unchanged in the brain. Dipyridamole, given before irradiation, significantly inhibited the increase of lipid peroxide after irradiation. These results suggest that dipyridamole may have radioprotective effects on aging mouse liver and spleen as well as on young mouse, and that inhibition of lipid peroxidation is a possible factor in the radioprotective effect of dipyridamole. (author)

Lipid-binding proteins modulate ligand-dependent trans-activation by peroxisome proliferator-activated receptors and localize to the nucleus as well as the cytoplasm

DEFF Research Database (Denmark)

Helledie, T; Antonius, M; Sorensen, R V

2000-01-01

Peroxisome proliferator-activated receptors (PPARs) are activated by a variety of fatty acids, eicosanoids, and hypolipidemic and insulin-sensitizing drugs. Many of these compounds bind avidly to members of a family of small lipid-binding proteins, the fatty acid-binding proteins (FABPs). Fatty...

Lipid rafts regulate PCB153-induced disruption of occludin and brain endothelial barrier function through protein phosphatase 2A and matrix metalloproteinase-2

Energy Technology Data Exchange (ETDEWEB)

Eum, Sung Yong, E-mail: seum@miami.edu; Jaraki, Dima; András, Ibolya E.; Toborek, Michal

2015-09-15

Occludin is an essential integral transmembrane protein regulating tight junction (TJ) integrity in brain endothelial cells. Phosphorylation of occludin is associated with its localization to TJ sites and incorporation into intact TJ assembly. The present study is focused on the role of lipid rafts in polychlorinated biphenyl (PCB)-induced disruption of occludin and endothelial barrier function. Exposure of human brain endothelial cells to 2,2′,4,4′,5,5′-hexachlorobiphenyl (PCB153) induced dephosphorylation of threonine residues of occludin and displacement of occludin from detergent-resistant membrane (DRM)/lipid raft fractions within 1 h. Moreover, lipid rafts modulated the reduction of occludin level through activation of matrix metalloproteinase 2 (MMP-2) after 24 h PCB153 treatment. Inhibition of protein phosphatase 2A (PP2A) activity by okadaic acid or fostriecin markedly protected against PCB153-induced displacement of occludin and increased permeability of endothelial cells. The implication of lipid rafts and PP2A signaling in these processes was further defined by co-immunoprecipitation of occludin with PP2A and caveolin-1, a marker protein of lipid rafts. Indeed, a significant MMP-2 activity was observed in lipid rafts and was increased by exposure to PCB153. The pretreatment of MMP-2 inhibitors protected against PCB153-induced loss of occludin and disruption of lipid raft structure prevented the increase of endothelial permeability. Overall, these results indicate that lipid raft-associated processes, such as PP2A and MMP-2 activation, participate in PCB153-induced disruption of occludin function in brain endothelial barrier. This study contributes to a better understanding of the mechanisms leading to brain endothelial barrier dysfunction in response to exposure to environmental pollutants, such as ortho-substituted PCBs. - Highlights: • PCB153 disturbed human brain endothelial barrier through disruption of occludin. • Lipid raft-associated PP

Binding of (/sup 3/H)imipramine to human platelet membranes with compensation for saturable binding to filters and its implication for binding studies with brain membranes

Energy Technology Data Exchange (ETDEWEB)

Phillips, O.M.; Wood, K.M.; Williams, D.C.

1984-08-01

Apparent specific binding of (/sup 3/H)imipramine to human platelet membranes at high concentrations of imipramine showed deviation from that expected of a single binding site, a result consistent with a low-affinity binding site. The deviation was due to displaceable, saturable binding to the glass fibre filters used in the assays. Imipramine, chloripramine, desipramine, and fluoxetine inhibited binding to filters whereas 5-hydroxytryptamine and ethanol were ineffective. Experimental conditions were developed that eliminated filter binding, allowing assay of high- and low-affinity binding to membranes. Failure to correct for filter binding may lead to overestimation of binding parameters, Bmax and KD for high-affinity binding to membranes, and may also be misinterpreted as indicating a low-affinity binding component in both platelet and brain membranes. Low-affinity binding (KD less than 2 microM) of imipramine to human platelet membranes was demonstrated and its significance discussed.

N-isopropyl-[123I]p-iodoamphetamine: single-pass brain uptake and washout; binding to brain synaptosomes; and localization in dog and monkey brain

International Nuclear Information System (INIS)

Winchell, H.S.; Horst, W.D.; Braun, L.; Oldendorf, W.H.; Hattner, R.; Parker, H.

1980-01-01

The kinetics of N-isopropyl-p-[ 123 I]iodoamphetamine in rat brains were determined by serial measurements of brain uptake index (BUI) after intracarotid injection; also studied were its effects on amine uptake and release in rat's brain cortical synaptosomes; and its in vivo distribution in the dog and monkey. No specific localization in brain nuclei of the dog was seen, but there was progressive accumulation in the eyes. Rapid initial brain uptake in the ketamine-sedated monkey was noted, and further slow brain uptake occurred during the next 20 min but without retinal localization. High levels of brain activity were maintained for several hours. The quantitative initial single-pass clearance of the agent in the brain suggests its use in evaluation of regional brain perfusion. Its interaction with brain amine-binding sites suggests its possible application in studies of cerebral amine metabolism

Safety profile of the intravenous administration of brain-targeted stable nucleic acid lipid particles

Directory of Open Access Journals (Sweden)

Mariana Conceição

2016-03-01

Full Text Available In a clinical setting, where multiple administrations of the therapeutic agent are usually required to improve the therapeutic outcome, it is crucial to assess the immunogenicity of the administered nanoparticles. In this data work, we investigated the safety profile of the repeated intravenous administration of brain-targeted stable nucleic acid lipid particles (RVG-9r-targeted SNALPs. To evaluate local activation of the immune system, we performed analysis of mouse tissue homogenates and sections from cerebellum. To investigate peripheral activation of the immune system, we used serum of mice that were intravenously injected with RVG-9r-targeted SNALPs. These data are related and were discussed in the accompanying research article entitled “Intravenous administration of brain-targeted stable nucleic acid lipid particles alleviates Machado–Joseph disease neurological phenotype” (Conceição et al., in press [1].

Lipid Microarray Biosensor for Biotoxin Detection.

Energy Technology Data Exchange (ETDEWEB)

Singh, Anup K.; Throckmorton, Daniel J.; Moran-Mirabal, Jose C.; Edel, Joshua B.; Meyer, Grant D.; Craighead, Harold G.

2006-05-01

We present the use of micron-sized lipid domains, patterned onto planar substrates and within microfluidic channels, to assay the binding of bacterial toxins via total internal reflection fluorescence microscopy (TIRFM). The lipid domains were patterned using a polymer lift-off technique and consisted of ganglioside-populated DSPC:cholesterol supported lipid bilayers (SLBs). Lipid patterns were formed on the substrates by vesicle fusion followed by polymer lift-off, which revealed micron-sized SLBs containing either ganglioside GT1b or GM1. The ganglioside-populated SLB arrays were then exposed to either Cholera toxin subunit B (CTB) or Tetanus toxin fragment C (TTC). Binding was assayed on planar substrates by TIRFM down to 1 nM concentration for CTB and 100 nM for TTC. Apparent binding constants extracted from three different models applied to the binding curves suggest that binding of a protein to a lipid-based receptor is strongly affected by the lipid composition of the SLB and by the substrate on which the bilayer is formed. Patterning of SLBs inside microfluidic channels also allowed the preparation of lipid domains with different compositions on a single device. Arrays within microfluidic channels were used to achieve segregation and selective binding from a binary mixture of the toxin fragments in one device. The binding and segregation within the microfluidic channels was assayed with epifluorescence as proof of concept. We propose that the method used for patterning the lipid microarrays on planar substrates and within microfluidic channels can be easily adapted to proteins or nucleic acids and can be used for biosensor applications and cell stimulation assays under different flow conditions. KEYWORDS. Microarray, ganglioside, polymer lift-off, cholera toxin, tetanus toxin, TIRFM, binding constant.4

The serotonin transporter in rhesus monkey brain: comparison of DASB and citalopram binding sites

International Nuclear Information System (INIS)

Zeng Zhizhen; Chen, T.-B.; Miller, Patricia J.; Dean, Dennis; Tang, Y.S.; Sur, Cyrille; Williams, David L.

2006-01-01

We have characterized the interaction of the serotonin transporter ligand [ 3 H]-N,N-dimethyl-2-(2-amino-4-cyanophenylthio)-benzylamine (DASB) with rhesus monkey brain in vitro using tissue homogenate binding and autoradiographic mapping. [ 3 H]-DASB, a tritiated version of the widely used [ 11 C] positron emission tomography tracer, was found to selectively bind to a single population of sites with high affinity (K d =0.20±0.04 nM). The serotonin transporter density (B max ) obtained for rhesus frontal cortex was found to be 66±8 fmol/mg protein using [ 3 H]-DASB, similar to the B max value obtained using the reference radioligand [ 3 H]-citalopram, a well-characterized and highly selective serotonin reuptake inhibitor (83±22 fmol/mg protein). Specific binding sites of both [ 3 H]-DASB and [ 3 H]-citalopram were similarly and nonuniformly distributed throughout the rhesus central nervous system, in a pattern consistent with serotonin transporter localization reported for human brain. Regional serotonin transporter densities, estimated from optical densities of the autoradiographic images, were well correlated between the two radioligands. Finally, DASB and fluoxetine showed dose-dependent full inhibition of [ 3 H]-citalopram binding in a competition autoradiographic study, with K i values in close agreement with those obtained from rhesus brain homogenates. This side-by-side comparison of [ 3 H]-DASB and [ 3 H]-citalopram binding sites in rhesus tissue homogenates and in adjacent rhesus brain slices provides additional support for the use of [ 11 C]-DASB to assess the availability and distribution of serotonin transporters in nonhuman primates

Methodological issues in protein and lipidic expressions in brain tissue exposed to Co60 based on DESI/MALDI-MS

International Nuclear Information System (INIS)

Soares, Matheus F.; Campos, Tarcísio P.R.; Augusti, Rodinei; Eberlin, Marcos N.; Vendramini, Pedro H.

2017-01-01

The present paper attempts to present some issues in the methodology of identifying lipid and protein changes in brain tissue induced by radiation. The goal was to address the analysis of the methodology and to investigate the feasibility of the generation of lipid/protein profiles of irradiated brain tissue, in order to identify radioinduced changes. Lipids and proteins are biomolecules with diverse structures and functionalities that participate in important intracellular processes. Changes in the lipid and the tissue protein profiles may indicate a cellular response to an external stimulus as well as the emergence of neoplasms or neurodegenerative diseases such as Alzheimer's. DESI-MS is a convenient method for identifying lipids and their spatial distribution in tissue beyond analytical quantification. DESI-MS allows the creation of an image of several low lipid m/z classes. MALDI-MS has already been a method used in the study of macromolecules as structural, membrane, hormone, neuromediator and immunological peptides. Through a full-scan matrix scan, with a m/z spectrum between 500-1000 for lipids and with a mass spectrum of 1000-15000 Da for proteins, the molecular profile can be analyzed. Generated pixel shape 2D chemical image. The produced image allows to associate the tissue distribution of the lipids and proteins with their chemical profile identified, allowing the verification of the changes radioinduced. Radiation triggers intense oxidative stress by increasing reactive oxygen species (ROS) and free radicals, causing DNA damage with consequent alterations in proteomics and cellular lipid explaining such changes in the lipid and protein expressions. The cellular morphophysiological changes are responsible for both the clonogenic inhibition and the induction of the apoptotic process. The images's production was directly dependent on the rigorous execution of the methodological procedures. Innumerable interferences could impair the image

Quantitative pharmacological analysis of 2-125I-iodomelatonin binding sites in discrete areas of the chicken brain

International Nuclear Information System (INIS)

Siuciak, J.A.; Krause, D.N.; Dubocovich, M.L.

1991-01-01

The authors have localized and characterized 2-125I-iodomelatonin binding sites in the chicken brain using in vitro quantitative autoradiography. Binding sites were widely distributed throughout the chicken brain, predominantly in regions associated with the visual system. The specific binding of 2-125I-iodomelatonin to discrete chicken brain areas was found to be saturable, reversible, and of high affinity. The specific binding of 2-125I-iodomelatonin (75 pm) was quantitated for 40 identifiable brain regions. Eight brain regions were chosen for binding characterization and pharmacological analysis: optic tectum, Edinger-Westphal nucleus, oculomotor nucleus, nucleus rotundus, ventral supraoptic decussation, ventrolateral geniculate nucleus, neostriatum, and ectostriatum. These regions showed no rostral-caudal gradient in 2-125I-iodomelatonin specific binding, and saturation analysis revealed a single class of high-affinity sites with KD values in the range of 33-48 pM and receptor site density (Bmax) ranging from 31 to 58 fmol/mg protein. Competition experiments carried out with various indoles revealed a similar order of pharmacological affinities in these areas: melatonin greater than 6-chloromelatonin greater than methoxyluzindole greater than N-acetylserotonin greater than luzindole much greater than 5-HT greater than 5-methoxytryptamine. The affinity constants determined by quantitative autoradiography for these compounds to compete for 2-125I-iodomelatonin binding in the optic tectum correlated well with the affinities in chicken brain membranes at 25 degrees C (r = 0.966; slope = 0.845; n = 7) and 0 degree C (r = 0.946; slope = 0.379; n = 7), chicken retinal membranes (r = 0.973; slope = 0.759; n = 7), and the potency or affinity of these compounds to affect the calcium-dependent release of 3H-dopamine from the rabbit retina (r = 0.902; slope = 0.506; n = 6)

Selective binding of 2-[{sup 125}I]iodo-nisoxetine to norepinephrine transporters in the brain

Energy Technology Data Exchange (ETDEWEB)

Kung, M.-P.; Choi, Seok-Rye; Hou, Catherine; Zhuang, Z.-P.; Foulon, Catherine; Kung, Hank F. E-mail: kunghf@sunmac.spect.upenn.edu

2004-07-01

A radioiodinated ligand, (R)-N-methyl-(2-[{sup 125}I]iodo-phenoxy)-3-phenylpropylamine, [{sup 125}I]2-INXT, targeting norepinephrine transporters (NET), was successfully prepared. A no-carrier-added product, [{sup 125}I]2-INXT, displayed a saturable binding with a high affinity (K{sub d}=0.06 nM) in the homogenates prepared from rat cortical tissues as well as from LLC-PK{sub 1} cells expressing NET. A relatively low number of binding sties (B{sub max}=55 fmol/mg protein) measured with [{sup 125}I]2-INXT in rat cortical homogenates is consistent with the value reported for a known NET ligand, [{sup 3}H]nisoxetine. Competition studies with various compounds on [{sup 125}I]2-INXT binding clearly confirmed the pharmacological specificity and selectivity for NET binding sites. Following a tail-vein injection of [{sup 125}I]2-INXT in rats, a good initial brain uptake was observed (0.56% dose at 2 min) followed by a slow washout from the brain (0.2% remained at 3 hours post-injection). The hypothalamus (a NET-rich region) to striatum (a region devoid of NET) ratio was 1.5 at 3 hours post-i.v. injection. Pretreatment of rats with nisoxetine significantly inhibited the uptake of [{sup 125}I]2-INXT (70-100% inhibition) in locus coeruleus, hypothalamus and raphe nuclei, regions known to have a high density of NET; whereas escitalopram, a serotonin transporter ligand, did not show a similar effect. Ex vivo autoradiography of rat brain sections of [{sup 125}I]2-INXT (at 3 hours after an i.v. injection) displayed an excellent regional brain localization pattern corroborated to the specific NET distribution in the brain. The specific brain localization was significantly reduced by a dose of nisoxetine pretreatment. Taken together, the data suggest that [{sup 123}I]2-INXT may be useful for mapping NET binding sites in the brain.

Phenylalanine-coupled solid lipid nanoparticles for brain tumor targeting

Energy Technology Data Exchange (ETDEWEB)

Kharya, Parul; Jain, Ashish; Gulbake, Arvind; Shilpi, Satish; Jain, Ankit; Hurkat, Pooja [Dr. Hari Singh Gour University, Pharmaceutical Research Projects Laboratory, Department of Pharmaceutical Sciences (India); Majumdar, Subrata [Bose Institute, Division of Molecular Medicine (India); Jain, Sanjay K., E-mail: drskjainin@yahoo.com [Dr. Hari Singh Gour University, Pharmaceutical Research Projects Laboratory, Department of Pharmaceutical Sciences (India)

2013-11-15

The purpose of this study is to investigate the targeting potential of amino acid (phenylalanine)-coupled solid lipid nanoparticles (SLN) loaded with ionically complexed doxorubicin HCl (Dox). Ionic complexation was used to enhance the loading efficiency and release characteristics of water soluble form of Dox. l-Type amino acid transporters (LAT1) are highly expressed on blood brain barrier as well as on many brain cancer cells, thus targeting LAT1 using phenylalanine improved anticancer activity of prepared nanocarrier. The phenylalanine-coupled SLN were characterized by fourier transform infrared spectroscopy, scanning electron microscope, transmission electron microscopy, particle size, zeta potential, entrapment efficiency and in vitro release. The particle size of the resulting SLN was found to be in the range of 163.3 ± 5.2 to 113.0 ± 2.6 nm, with a slightly negative surface charge. In ex vivo study on C6 glioma cell lines, the cellular cytotoxicity of the SLN was highly increased when coupled with phenylalanine. In addition, stealthing sheath of PEG present on the surface of the SLN enhanced the cellular uptake of the SLN on C6 glioma cell line. Results of biodistribution and fluorescence studies clearly revealed that phenylalanine-coupled SLN could deliver high amount of drug into the brain tumor cells and showed the brain-targeting potential.

Risperidone treatment increases CB1 receptor binding in rat brain

DEFF Research Database (Denmark)

Secher, Anna; Husum, Henriette; Holst, Birgitte

2010-01-01

, the ghrelin receptor, neuropeptide Y, adiponectin and proopiomelanocortin. We investigated whether the expression of these factors was affected in rats chronically treated with the antipsychotic risperidone. METHODS: Male Sprague-Dawley rats were treated with risperidone (1.0 mg/kg/day) or vehicle (20...... showed that risperidone treatment altered CB(1) receptor binding in the rat brain. Risperidone-induced adiposity and metabolic dysfunction in the clinic may be explained by increased CB(1) receptor density in brain regions involved in appetite and regulation of metabolic function....

(/sup 3/H)-beta-endorphin binding in rat brain

Energy Technology Data Exchange (ETDEWEB)

Houghten, R.A.; Johnson, N.; Pasternak, G.W.

1984-10-01

The binding of (/sup 3/H)-beta-endorphin to rat brain homogenates is complex. Although Scatchard analysis of saturation studies yields a straight line, detailed competition studies are multiphasic, suggesting that even at low concentrations of the compound, the /sup 3/H-ligand is binding to more than one class of site. A portion of (/sup 3/H)-beta-endorphin binding is sensitive to low concentrations of morphine or D-Ala2-Leu5-enkephalin (less than 5 nM). The inhibition observed with each compound alone (5 nM) is the same as that seen with both together (each at 5 nM). Thus, the binding remaining in the presence of both morphine and the enkephalin does not correspond to either mu or delta sites. The portion of (/sup 3/H)-beta-endorphin binding that is inhibited under these conditions appears to be equally sensitive to both morphine and the enkephalin and may correspond to mu1 sites. Treating membrane homogenates with naloxonazine, a mu1 selective antagonist, lowers (/sup 3/H)-beta-endorphin binding to the same degree as morphine and D-Ala2-Leu5-enkephalin alone or together. This possible binding of (/sup 3/H)-beta-endorphin to mu1 sites is consistent with the role of mu1 sites in beta-endorphin analgesia and catalepsy in vivo.

Reconstitution of high-affinity opioid agonist binding in brain membranes

Energy Technology Data Exchange (ETDEWEB)

Remmers, A.E.; Medzihradsky, F. (Univ. of Michigan Medical School, Ann Arbor (United States))

1991-03-15

In synaptosomal membranes from rat brain cortex, the {mu} selective agonist ({sup 3}H)dihydromorphine in the absence of sodium, and the nonselective antagonist ({sup 3}H)naltrexone in the presence of sodium, bound to two populations of opioid receptor sites with K{sub d} values of 0.69 and 8.7 nM for dihydromorphine, and 0.34 and 5.5 nM for naltrexone. The addition of 5 {mu}M guanosine 5{prime}-({gamma}-thio)triphosphate (GTP({gamma}S)) strongly reduced high-affinity agonist but not antagonist binding. Exposure of the membranes to high pH reduced the number of GTP({gamma}-{sup 35}S) binding sites by 90% and low K{sub m}, opioid-sensitive GTPase activity by 95%. In these membranes, high-affinity agonist binding was abolished and modulation of residual binding by GTP({gamma}S) was diminished. Alkali treatment of the glioma cell membranes prior to fusion inhibited most of the low K{sub m} GTPase activity and prevented the reconstitution of agonist binding. The results show that high-affinity opioid agonist binding reflects the ligand-occupied receptor - guanine nucleotide binding protein complex.

2-[125I]iodomelatonin binding sites in hamster brain membranes: pharmacological characteristics and regional distribution

International Nuclear Information System (INIS)

Duncan, M.J.; Takahashi, J.S.; Dubocovich, M.L.

1988-01-01

Studies in a variety of seasonally breeding mammals have shown that melatonin mediates photoperiodic effects on reproduction. Relatively little is known, however, about the site(s) or mechanisms of action of this hormone for inducing reproductive effects. Although binding sites for [3H]melatonin have been reported previously in bovine, rat, and hamster brain, the pharmacological selectivity of these sites was never demonstrated. In the present study, we have characterized binding sites for a new radioligand, 2-[125I]iodomelatonin, in brains from a photoperiodic species, the Syrian hamster. 2-[125I]Iodomelatonin labels a high affinity binding site in hamster brain membranes. Specific binding of 2-[125I]iodomelatonin is rapid, stable, saturable, and reversible. Saturation studies demonstrated that 2-[125I]iodomelatonin binds to a single class of sites with an affinity constant (Kd) of 3.3 +/- 0.5 nM and a total binding capacity (Bmax) of 110.2 +/- 13.4 fmol/mg protein (n = 4). The Kd value determined from kinetic analysis (3.1 +/- 0.9 nM; n = 5) was very similar to that obtained from saturation experiments. Competition experiments showed that the relative order of potency of a variety of indoles for inhibition of 2-[125I]iodomelatonin binding site to hamster brain membranes was as follows: 6-chloromelatonin greater than or equal to 2-iodomelatonin greater than N-acetylserotonin greater than or equal to 6-methoxymelatonin greater than or equal to melatonin greater than 6-hydroxymelatonin greater than or equal to 6,7-dichloro-2-methylmelatonin greater than 5-methoxytryptophol greater than 5-methoxytryptamine greater than or equal to 5-methoxy-N,N-dimethyltryptamine greater than N-acetyltryptamine greater than serotonin greater than 5-methoxyindole (inactive)

Lipid-laden cells differentially distributed in the aging brain are functionally active and correspond to distinct phenotypes

Science.gov (United States)

Shimabukuro, Marilia Kimie; Langhi, Larissa Gutman Paranhos; Cordeiro, Ingrid; Brito, José M.; Batista, Claudia Maria de Castro; Mattson, Mark P.; de Mello Coelho, Valeria

2016-01-01

We characterized cerebral Oil Red O-positive lipid-laden cells (LLC) of aging mice evaluating their distribution, morphology, density, functional activities and inflammatory phenotype. We identified LLC in meningeal, cortical and neurogenic brain regions. The density of cerebral LLC increased with age. LLC presenting small lipid droplets were visualized adjacent to blood vessels or deeper in the brain cortical and striatal parenchyma of aging mice. LLC with larger droplets were asymmetrically distributed in the cerebral ventricle walls, mainly located in the lateral wall. We also found that LLC in the subventricular region co-expressed beclin-1 or LC3, markers for autophagosome or autophagolysosome formation, and perilipin (PLIN), a lipid droplet-associated protein, suggesting lipophagic activity. Some cerebral LLC exhibited β galactosidase activity indicating a senescence phenotype. Moreover, we detected production of the pro-inflammatory cytokine TNF-α in cortical PLIN+ LLC. Some cortical NeuN+ neurons, GFAP+ glia limitans astrocytes, Iba-1+ microglia and S100β+ ependymal cells expressed PLIN in the aging brain. Our findings suggest that cerebral LLC exhibit distinct cellular phenotypes and may participate in the age-associated neuroinflammatory processes. PMID:27029648

Lipid-laden cells differentially distributed in the aging brain are functionally active and correspond to distinct phenotypes.

Science.gov (United States)

Shimabukuro, Marilia Kimie; Langhi, Larissa Gutman Paranhos; Cordeiro, Ingrid; Brito, José M; Batista, Claudia Maria de Castro; Mattson, Mark P; Mello Coelho, Valeria de

2016-03-31

We characterized cerebral Oil Red O-positive lipid-laden cells (LLC) of aging mice evaluating their distribution, morphology, density, functional activities and inflammatory phenotype. We identified LLC in meningeal, cortical and neurogenic brain regions. The density of cerebral LLC increased with age. LLC presenting small lipid droplets were visualized adjacent to blood vessels or deeper in the brain cortical and striatal parenchyma of aging mice. LLC with larger droplets were asymmetrically distributed in the cerebral ventricle walls, mainly located in the lateral wall. We also found that LLC in the subventricular region co-expressed beclin-1 or LC3, markers for autophagosome or autophagolysosome formation, and perilipin (PLIN), a lipid droplet-associated protein, suggesting lipophagic activity. Some cerebral LLC exhibited β galactosidase activity indicating a senescence phenotype. Moreover, we detected production of the pro-inflammatory cytokine TNF-α in cortical PLIN(+) LLC. Some cortical NeuN(+) neurons, GFAP(+) glia limitans astrocytes, Iba-1(+) microglia and S100β(+) ependymal cells expressed PLIN in the aging brain. Our findings suggest that cerebral LLC exhibit distinct cellular phenotypes and may participate in the age-associated neuroinflammatory processes.

Ropizine concurrently enhances and inhibits [3H] dextromethorpan binding to different structures of the guinea pig brain: Autoradiographic evidence for multiple binding sites

International Nuclear Information System (INIS)

Canoll, P.D.; Smith, P.R.; and Musacchio, J.M.

1990-01-01

Ropizine produces a simultaneous enhancement and inhibition of [ 3 H] dextromethorphan (DM) high-affinity binding to different areas of the guinea pig brain. These results imply that there are two distinct types of high-affinity [ 3 H]DM binding sites, which are present in variable proportions in different brain structures. The ropizine-enhances [ 3 H]DM binding type was preferentially inhibited by (+)-pentazocine. This is consistent with the presumption that the (+)-pentazocine-sensitive site is identical with the common site for DM and 3-(-3-Hydroxphenyl)-N-(1-propyl)piperidine ((+)-3-PPP). The second binding type, which is inhibited by ropizine and is not so sensitive to (+)- pentazocine, has not been fully characterized. This study demonstrates that the biphasic effects to ropizine are due, at least in part, to the effects of ropizine on two different types of [ 3 H]DM binding sites. However, this study does not rule out that the common DM/(+)-3-PPP site also might be inhibited by higher concentrations of ropizine

The serotonin transporter in rhesus monkey brain: comparison of DASB and citalopram binding sites

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Zeng Zhizhen [Imaging Department, Merck Research Laboratories, West Point, PA 19486 (United States)]. E-mail: zhizhen_zeng@merck.com; Chen, T.-B. [Imaging Department, Merck Research Laboratories, West Point, PA 19486 (United States); Miller, Patricia J. [Imaging Department, Merck Research Laboratories, West Point, PA 19486 (United States); Dean, Dennis [Labeled Compound Synthesis Group, Drug Metabolism, Merck Research Laboratories, Rahway, NJ 07065-0900 (United States); Tang, Y.S. [Labeled Compound Synthesis Group, Drug Metabolism, Merck Research Laboratories, Rahway, NJ 07065-0900 (United States); Sur, Cyrille [Imaging Department, Merck Research Laboratories, West Point, PA 19486 (United States); Williams, David L. [Imaging Department, Merck Research Laboratories, West Point, PA 19486 (United States)

2006-05-15

We have characterized the interaction of the serotonin transporter ligand [{sup 3}H]-N,N-dimethyl-2-(2-amino-4-cyanophenylthio)-benzylamine (DASB) with rhesus monkey brain in vitro using tissue homogenate binding and autoradiographic mapping. [{sup 3}H]-DASB, a tritiated version of the widely used [{sup 11}C] positron emission tomography tracer, was found to selectively bind to a single population of sites with high affinity (K {sub d}=0.20{+-}0.04 nM). The serotonin transporter density (B {sub max}) obtained for rhesus frontal cortex was found to be 66{+-}8 fmol/mg protein using [{sup 3}H]-DASB, similar to the B {sub max} value obtained using the reference radioligand [{sup 3}H]-citalopram, a well-characterized and highly selective serotonin reuptake inhibitor (83{+-}22 fmol/mg protein). Specific binding sites of both [{sup 3}H]-DASB and [{sup 3}H]-citalopram were similarly and nonuniformly distributed throughout the rhesus central nervous system, in a pattern consistent with serotonin transporter localization reported for human brain. Regional serotonin transporter densities, estimated from optical densities of the autoradiographic images, were well correlated between the two radioligands. Finally, DASB and fluoxetine showed dose-dependent full inhibition of [{sup 3}H]-citalopram binding in a competition autoradiographic study, with K {sub i} values in close agreement with those obtained from rhesus brain homogenates. This side-by-side comparison of [{sup 3}H]-DASB and [{sup 3}H]-citalopram binding sites in rhesus tissue homogenates and in adjacent rhesus brain slices provides additional support for the use of [{sup 11}C]-DASB to assess the availability and distribution of serotonin transporters in nonhuman primates.

The interaction of substituted benzamides with brain benzodiazepine binding sites in vitro.

Science.gov (United States)

Horton, R W; Lowther, S; Chivers, J; Jenner, P; Marsden, C D; Testa, B

1988-08-01

1. The interaction of substituted benzamides with brain benzodiazepine (BDZ) binding sites was examined by their ability to displace [3H]-flunitrazepam ([3H]-FNM) from specific binding sites in bovine cortical membranes in vitro. 2. Clebopride, Delagrange 2674, Delagrange 2335 and BRL 20627 displayed concentration-dependent displacement of [3H]-FNM with IC50 values of 73 nM, 132 nM, 7.7 microM and 5.9 microM, respectively. Other substituted benzamides including metoclopramide, sulpiride, tiapride, sultopride and cisapride were inactive at 10(-5) M. 3. Inhibition by clebopride and Delagrange 2674 of [3H]-FNM binding was apparently competitive and readily reversible. 4. In the presence of gamma-aminobutyric acid (GABA), the ability of diazepam and Delagrange 2674 to displace [3H]-Ro 15-1788 binding was increased 3.6 and 1.6 fold respectively, compared to the absence of GABA, while ethyl beta-carboline-3-carboxylate (beta CCE) and clebopride were less potent in the presence of GABA. 5. Diazepam was 30 fold less potent at displacing [3H]-Ro 15-1788 in membranes that had been photoaffinity labelled with FNM than in control membranes, whereas the potency of beta CCE did not differ. Clebopride and Delagrange 2674 showed a less than two fold loss of potency in photoaffinity labelled membranes. 6. The pattern of binding of clebopride and Delagrange 2674 in these in vitro tests is similar to that found previously with partial agonists or antagonists at BDZ binding sites. 7. Clebopride and Delagrange 2674 inhibited [3H]-FNM binding with similar potency in rat cerebellar and hippocampal membranes, suggesting they have no selectivity for BDZ1 and BDZ2 binding sites. 8. Clebopride and Delagrange 2674 are structurally dissimilar to other BDZ ligands and represent another chemical structure to probe brain BDZ binding sites.

Insulin sensitivity is independent of lipid binding protein trafficking at the plasma membrane in human skeletal muscle

DEFF Research Database (Denmark)

Jordy, Andreas Børsting; Serup, Annette Karen; Karstoft, Kristian

2014-01-01

The aim of the present study was to investigate lipid-induced regulation of lipid binding proteins in human skeletal muscle and the impact hereof on insulin sensitivity. Eleven healthy male subjects underwent a 3-day hyper-caloric and high-fat diet regime. Muscle biopsies were taken before......-regulated by increased fatty acid availability. This suggests a time dependency in the up-regulation of FAT/CD36 and FABPpm protein during high availability of plasma fatty acids. Furthermore, we did not detect FATP1 and FATP4 protein in giant sarcolemmal vesicles obtained from human skeletal muscle. In conclusion......, this study shows that a short-term lipid-load increases mRNA content of key lipid handling proteins in human muscle. However, decreased insulin sensitivity after high-fat diet is not accompanied with relocation of FAT/CD36 or FABPpm protein to the sarcolemma. Finally, FATP1 and FATP4 protein could...

Effect of different commercial fat sources on brain, liver and blood lipid profiles of rats in growth phase.

Science.gov (United States)

Angelis-Pereira, Michel Cardoso de; Barcelos, Maria de Fátima Píccolo; Pereira, Juciane de Abreu Ribeiro; Pereira, Rafaela Corrêa; Souza, Raimundo Vicente de

2017-12-01

To investigate the fatty acid content of different fat sources and evaluate the effect of them on plasma and hepatic lipids and on the fatty acid profile of the brain tissue of Wistar rats. Thirty male albino Wistar rats received for 59 days, the following diets: diet added of margarine with low content of polyunsaturated fatty acids (PUFA); diet added of margarine with high content of PUFA; diet added of butter; diet added of hydrogenated vegetable fat; diet added of soybean oil. Fatty acid profile of the lipid sources, blood and hepatic lipids fractions and fatty acid profile of the brain tissue were determined. Margarine consumption of provided different responses as to concentrations of blood and hepatic lipid fractions. Intake of butter and hydrogenated increased LDL-c/HDL-c ratio, being the steepest increase promoted by hydrogenated vegetable fat, which also raised LDL-c levels expressively. All fats used in the treatments reduced the cerebral concentration of docosahexaenoic acid when compared to soybean oil (control). The different fat sources commonly consumed by population provided different responses in vivo. This is particularly relevant considering the role of these lipids in the incidence and prevention of cardiovascular diseases.

Multiple [3H]-nemonapride binding sites in calf brain.

Science.gov (United States)

Helmeste, D M; Tang, S W; Li, M; Fang, H

1997-07-01

[3H]-Nemonapride has been the ligand of choice to label D4 dopamine receptors. Its specificity was questioned when it was discovered that sigma (sigma) sites were also labeled by [3H]-nemonapride. To further characterize the binding of [3H]-nemonapride, three areas of calf brain (striatum, frontal cortex and cerebellum) were examined. In all three areas, [3H]-nemonapride labeled multiple sites. Dopaminergic and sigma sites were the most prominent. The sigma binding profile was sigma-1 like with a Ki binding profile as follows (in order of decreasing potency): haloperidol, PPAP, pentazocine, DTG, U-50488, R(+)-3-PPP. Experiments using sulpiride and pentazocine to block striatal dopaminergic and sigma sites, respectively, revealed additional, not previously characterized binding sites for [3H]-nemonapride. One component which was present in striatum but not in frontal cortex or cerebellum, had affinity for some neuroleptics and WB-4101, but not for typical serotonergic agents. Thus, [3H]-nemonapride has no selectivity for dopamine receptors unless stringent experimental conditions are met.

Reduction in (/sup 3/H)-corticosterone binding to cytoplasmic receptors in the brain of diabetic rats

Energy Technology Data Exchange (ETDEWEB)

Fridman, O; Foglia, V G; de Nicola, A F [Instituto de Biologia y Medicina Experimental, Buenos Aires (Argentina). Lab. de Esteroides

1978-07-01

The binding of (1,2,6,7-/sup 3/H)-corticosterone was studied in brain cytosol from normal and streptozotocin-diabetic male rats. The experiments were performed under conditions of incubation time (4h), temperature (0-4/sup 0/C), time after adrenalectomy (6 days) and corticosterone concentrations (1.2 x 10/sup -8/ and 1.15 x 10/sup -9/M) previously established for determining binding activity in the brain of normal rats. The binding of (/sup 3/H)-corticosterone was found invariably lower in cytosol of the brain from diabetic rats, studied under three different conditions in non-adrenalectomized animals, in adrenalectomized using a non-saturating corticosterone concentration, and in adrenalectomized plus a saturating steroid concentration. These results support previous contentions that the diminished sensitivity to the negative feedback for steroids which is present in diabetics, may be related to a reduction in binding capacity for corticoids in the central nervous system.

Fatty acid composition of total lipids and phospholipids of muscular tissue and brain of rats under the impact of vibration

Directory of Open Access Journals (Sweden)

N. M. Kostyshyn

2016-06-01

Full Text Available Fatty acids are important structural components of biological membranes, energy substrate of cells involved in fixing phospholipid bilayer proteins, and acting as regulators and modulators of enzymatic activity. Under the impact of vibration oscillations there can occur shifts in the ratio of different groups of fatty acids, and degrees of their saturation may change. The imbalance between saturated, monounsaturated and polyunsaturated fatty acids, which occurs later in the cell wall, disrupts fluidity and viscosity of lipid phase and causes abnormal cellular metabolism. Aim. In order to study the impact of vibration on the level of fatty acids of total lipids in muscular tissue and fatty acid composition of phospholipids in muscles and brain, experimental animals have been exposed to vertical vibration oscillations with different frequency for 28 days. Methods and results. Tissues fragments of hip quadriceps and brain of rats were used for obtaining methyl esters of fatty acids studied by the method of gas-liquid chromatography. It was found that the lipid content, ratio of its separate factions and fatty acid composition in muscular tissue and brain of animals with the action of vibration considerably varies. With the increase of vibration acceleration tendency to increase in absolute quantity of total lipids fatty acids can be observed at the account of increased level of saturated and monounsaturated ones. These processes are caused by activation of self-defense mechanisms of the body under the conditions of deviations from stabilized physiological norm, since adaptation requires certain structural and energy costs. Increase in the relative quantity of saturated and monounsaturated fatty acids in phospholipids of muscles and brain and simultaneous reduction in concentration of polyunsaturated fatty acids are observed. Conclusion. These changes indicate worsening of structural and functional organization of muscles and brain cell membranes of

(/sup 3/H)diprenorphine binding to kappa-sites in guinea-pig and rat brain: Evidence for apparent heterogeneity

Energy Technology Data Exchange (ETDEWEB)

Wood, M.S.; Traynor, J.R.

1989-07-01

The binding of the unselective opioid antagonist (/sup 3/H)diprenorphine to homogenates prepared from rat brain and from guinea-pig brain and cerebellum has been studied in HEPES buffer containing 10 mM Mg2+ ions. Sequential displacement of bound (/sup 3/H)diprenorphine by ligands with selectivity for mu-, delta-, and kappa-opioid receptors uncovers the multiple components of binding. In the presence of cold ligands that occupy all mu-, delta-, and kappa-sites, opioid binding still remains. This binding represents 20% of total specific sites and is displaced by naloxone. The nature of these undefined opioid binding sites is discussed.

Methodological issues in protein and lipidic expressions in brain tissue exposed to Co{sup 60} based on DESI/MALDI-MS

Energy Technology Data Exchange (ETDEWEB)

Soares, Matheus F.; Campos, Tarcísio P.R.; Augusti, Rodinei, E-mail: matheus.soares@gmail.com, E-mail: tprcampos@pq.cnpq.br, E-mail: augusti.rodinei@gmail.com, E-mail: augusti@ufmg.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte (Brazil); Eberlin, Marcos N.; Vendramini, Pedro H., E-mail: eberlin@iqm.unicamp.br, E-mail: ph_vendramini@yahoo.com.br [Universidade de Campinas (UNICAMP), SP (Brazil). Thompson Mass Spectroscopy Laboratory

2017-07-01

The present paper attempts to present some issues in the methodology of identifying lipid and protein changes in brain tissue induced by radiation. The goal was to address the analysis of the methodology and to investigate the feasibility of the generation of lipid/protein profiles of irradiated brain tissue, in order to identify radioinduced changes. Lipids and proteins are biomolecules with diverse structures and functionalities that participate in important intracellular processes. Changes in the lipid and the tissue protein profiles may indicate a cellular response to an external stimulus as well as the emergence of neoplasms or neurodegenerative diseases such as Alzheimer's. DESI-MS is a convenient method for identifying lipids and their spatial distribution in tissue beyond analytical quantification. DESI-MS allows the creation of an image of several low lipid m/z classes. MALDI-MS has already been a method used in the study of macromolecules as structural, membrane, hormone, neuromediator and immunological peptides. Through a full-scan matrix scan, with a m/z spectrum between 500-1000 for lipids and with a mass spectrum of 1000-15000 Da for proteins, the molecular profile can be analyzed. Generated pixel shape 2D chemical image. The produced image allows to associate the tissue distribution of the lipids and proteins with their chemical profile identified, allowing the verification of the changes radioinduced. Radiation triggers intense oxidative stress by increasing reactive oxygen species (ROS) and free radicals, causing DNA damage with consequent alterations in proteomics and cellular lipid explaining such changes in the lipid and protein expressions. The cellular morphophysiological changes are responsible for both the clonogenic inhibition and the induction of the apoptotic process. The images's production was directly dependent on the rigorous execution of the methodological procedures. Innumerable interferences could impair the image

Bidirectional lipid droplet velocities are controlled by differential binding strengths of HCV core DII protein.

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Rodney K Lyn

Full Text Available Host cell lipid droplets (LD are essential in the hepatitis C virus (HCV life cycle and are targeted by the viral capsid core protein. Core-coated LDs accumulate in the perinuclear region and facilitate viral particle assembly, but it is unclear how mobility of these LDs is directed by core. Herein we used two-photon fluorescence, differential interference contrast imaging, and coherent anti-Stokes Raman scattering microscopies, to reveal novel core-mediated changes to LD dynamics. Expression of core protein's lipid binding domain II (DII-core induced slower LD speeds, but did not affect directionality of movement on microtubules. Modulating the LD binding strength of DII-core further impacted LD mobility, revealing the temporal effects of LD-bound DII-core. These results for DII-core coated LDs support a model for core-mediated LD localization that involves core slowing down the rate of movement of LDs until localization at the perinuclear region is accomplished where LD movement ceases. The guided localization of LDs by HCV core protein not only is essential to the viral life cycle but also poses an interesting target for the development of antiviral strategies against HCV.

Guanine nucleotide-binding protein regulation of melatonin receptors in lizard brain

International Nuclear Information System (INIS)

Rivkees, S.A.; Carlson, L.L.; Reppert, S.M.

1989-01-01

Melatonin receptors were identified and characterized in crude membrane preparations from lizard brain by using 125 I-labeled melatonin ( 125 I-Mel), a potent melatonin agonist. 125 I-Mel binding sites were saturable; Scatchard analysis revealed high-affinity and lower affinity binding sites, with apparent K d of 2.3 ± 1.0 x 10 -11 M and 2.06 ± 0.43 x 10 -10 M, respectively. Binding was reversible and inhibited by melatonin and closely related analogs but not by serotonin or norepinephrine. Treatment of crude membranes with the nonhydrolyzable GTP analog guanosine 5'-[γ-thio]triphosphate (GTP[γS]), significantly reduced the number of high-affinity receptors and increased the dissociation rate of 125 I-Mel from its receptor. Furthermore, GTP[γS] treatment of ligand-receptor complexes solubilized by Triton X-100 also led to a rapid dissociation of 125 I-Mel from solubilized ligand-receptor complexes. Gel filtration chromatography of solubilized ligand-receptor complexes revealed two major peaks of radioactivity corresponding to M r > 400,000 and M r ca. 110,000. This elution profile was markedly altered by pretreatment with GTP[γS] before solubilization; only the M r 110,000 peak was present in GTP[γS]-pretreated membranes. The results strongly suggest that 125 I-mel binding sites in lizard brain are melatonin receptors, with agonist-promoted guanine nucleotide-binding protein (G protein) coupling and that the apparent molecular size of receptors uncoupled from G proteins is about 110,000

Characterization of (/sup 3/H)paroxetine binding in rat brain

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Marcusson, J.O.; Bergstroem, M.E.; Eriksson, K.; Ross, S.B.

1988-06-01

The binding of the 5-hydroxytryptamine (5-HT, serotonin) uptake inhibitor (3H)paroxetine to rat cortical homogenates has been characterized. The effect of tissue concentration was examined and, with 0.75 mg wet weight tissue/ml in a total volume of 1,600 microliter, the binding was optimized with an apparent dissociation constant (KD) of 0.03-0.05 nM. Competition experiments with 5-HT, citalopram, norzimeldine, and desipramine revealed a high (90%) proportion of displaceable binding that fitted a single-site binding model. Fluoxetine and imipramine revealed, in addition to a high-affinity (nanomolar) site, also a low-affinity (micromolar) site representing approximately 10% of the displaceable binding. The specificity of the (3H)paroxetine binding was emphasized by the fact that 5-HT was the only active neurotransmitter bound and that the serotonin S1 and S2 antagonist methysergide was without effect on the binding. Both 5-HT- and fluoxetine-sensitive (3H)paroxetine binding was completely abolished after protease treatment, suggesting that the binding site is of protein nature. Saturation studies with 5-HT (100 microM) sensitive (3H)paroxetine binding were also consistent with a single-site binding model, and the binding was competitively inhibited by 5-HT and imipramine. The number of binding sites (Bmax) for 5-HT-sensitive (3H)paroxetine and (3H)imipramine binding was the same, indicating that the radioligands bind to the same sites. Lesion experiments with p-chloroamphetamine resulted in a binding in frontal and parietal cortices becoming undetectable and a greater than 60% reduction in the striatum and hypothalamus, indicating a selective localization on 5-HT terminals. Together these findings suggest that (3H)paroxetine specifically and selectively labels the substrate recognition site for 5-HT uptake in rat brain.

Inhibition of lipid peroxidation induced by γ- radiation and AAPH in rat liver and brain mitochondria by mushrooms

International Nuclear Information System (INIS)

Lakshmi, B.; Janardhanan, K.K.; Tilak, J.C.; Devasagayam, T.P.A.; Adhikari, S.

2005-01-01

Exposure to radiation or 2.2' Azobis(2-amidopropane) dihydrochloride (AAPH) induces generation of reactive oxygen species (ROS) especially hydroxyl radical ( . OH) and peroxyl radical (ROO . ), which are capable of inducing lipid peroxidation. Our earlier studies have demonstrated that extracts of the medicinal and edible mushrooms Ganoderma lucidum, Pleurotus florida, Pleurotus sajor-caju and Phellinus rimosus possessed significant antioxidant activity, measured as radical scavenging. In the present study, we examined the protective effect of these mushroom extracts against radiation- and AAPH-induced lipid peroxidation using rat liver and brain mitochondria as model systems. The results obtained showed that the investigated mushroom extracts significantly inhibited the formation of lipid hydroperoxide and thiobarbituric acid reactive substances, indicating membrane protective effects. The finding suggests the profound protective effect of the extracts of the fruiting bodies of G. lucidum, P. florida, P. sajor-caju and P. rimosus against lipid peroxidation by two major forms of ROS capable of inducing this type of damage in a major organelle, the mitochondria from both rat liver and brain. This observation can possibly explain the health benefits of these mushrooms. (author)

Tween 80 containing lipid nanoemulsions for delivery of indinavir to brain

Directory of Open Access Journals (Sweden)

Kandadi Prabhakar

2013-09-01

Full Text Available Indinavir is a protease inhibitor used in the treatment of HIV infection. However, it has limited efficacy in eradicating the virus in the brain due to efflux by P-glycoprotein (P-gp expressed at the blood–brain barrier (BBB. The objective of this work was to develop an o/w lipid nanoemulsion (LNE of indinavir using Tween 80 as co-emulsifier to improve its brain specific delivery. LNEs were prepared with different compositions and were characterized for globule size, polydispersity index, zeta potential and in vitro drug release. Five formulations were then evaluated for drug content, entrapment efficiency and stability after which brain uptake studies were carried out using fluorescent labeled LNEs and pharmacokinetic (PK and tissue distribution studies were conducted after intravenous administration in mice. Brain uptake of indinavir was shown to be improved for a 1% Tween 80 containing formulation (F5 compared to a formulation containing 0.3% cholesterol (F2. In PK studies, the brain level of indinavir subsequent to administration of F5 was significantly (P<0.05 higher than produced by administration of a drug solution (2.44-fold or a control nanoemulsion (F1 (1.48-fold or formulation F2 (1.6-fold. The increased brain specific accumulation of indinavir from F5 is probably due to enhanced low density lipoprotein-mediated endocytosis and P-gp inhibition by Tween 80 at the BBB. These results suggest Tween 80 containing LNEs could provide a simple but effective means of delivering indinavir to brain.

Fatty Acid Amide Hydrolase Binding in Brain of Cannabis Users: Imaging with the Novel Radiotracer [11C]CURB

Science.gov (United States)

Boileau, Isabelle; Mansouri, Esmaeil; Williams, Belinda; Le Foll, Bernard; Rusjan, Pablo; Mizrahi, Romina; Tyndale, Rachel F.; Huestis, Marilyn A.; Payer, Doris E.; Wilson, Alan A.; Houle, Sylvain; Kish, Stephen J.; Tong, Junchao

2016-01-01

Background One of the major mechanisms for terminating the actions of the endocannabinoid anandamide is hydrolysis by fatty acid amide hydrolase (FAAH) and inhibitors of the enzyme were suggested as potential treatment for human cannabis dependence. However, the status of brain FAAH in cannabis use disorder is unknown. Methods Brain FAAH binding was measured with positron emission tomography and [11C]CURB in 22 healthy control subjects and ten chronic, frequent cannabis users during early abstinence. The FAAH genetic polymorphism (rs324420) and blood, urine and hair levels of cannabinoids and metabolites were determined. Results In cannabis users FAAH binding was significantly lower by 14–20% across the brain regions examined as compared to matched control subjects (overall Cohen’s d=0.96). Lower binding was negatively correlated with cannabinoid concentrations in blood and urine and was associated with higher trait impulsiveness. Conclusions Lower FAAH binding levels in the brain may be a consequence of chronic and recent cannabis exposure and could contribute to cannabis withdrawal. This effect should be considered in the development of novel treatment strategies for cannabis use disorder that target FAAH and endocannabinoids. Further studies are needed to examine possible changes in FAAH binding during prolonged cannabis abstinence and whether lower FAAH binding predates drug use. PMID:27345297

Characterization of a high affinity cocaine binding site in rat brain

International Nuclear Information System (INIS)

Calligaro, D.; Eldefrawi, M.

1986-01-01

Binding of [ 3 H]cocaine to synaptic membranes from whole rat brain was reversible and saturable. Nonlinear regression analysis of binding isotherms indicated two binding affinities: one with k/sub d/ = 16 nM, B/sub max/ = 0.65 pmoles/mg protein and the other with K/sub d/ = 660 nM, B/sub max/ = 5.1 pmoles/mg protein. The high-affinity binding of [ 3 H]cocaine was sensitive to the actions of trypsin and chymotrypsin but not carboxypeptidase, and was eliminated by exposure of the membranes to 95 0 C for 5 min. Specific binding at 2 nM was higher at pH 8.8 than at pH 7.0. Binding of [ 3 H]cocaine (15 nM) was inhibited by increasing concentrations of Na + ions. Several cocaine analogues, neurotransmitter uptake inhibitors and local anesthetics displaced specific [ 3 H]cocaine binding at 2 nM with various potencies. The cocaine analogue (-)-norcocaine was the most potent (IC 50 = 10 nM), while the local anesthetic tetracaine was the least potent in inhibiting [ 3 H]cocaine binding. Several biogenic amine uptake inhibitors, including tricyclic antidepressants and phencyclidine, had IC 50 values below μM concentrations

The Structural Basis for Lipid and Endotoxin Binding in RP105-MD-1, and Consequences for Regulation of Host Lipopolysaccharide Sensitivity.

Science.gov (United States)

Ortiz-Suarez, Maite L; Bond, Peter J

2016-01-05

MD-1 is a member of the MD-2-related lipid-recognition (ML) family, and associates with RP105, a cell-surface protein that resembles Toll-like receptor 4 (TLR4). The RP105⋅MD-1 complex has been proposed to play a role in fine-tuning the innate immune response to endotoxin such as bacterial lipopolysaccharide (LPS) via TLR4⋅MD-2, but controversy surrounds its mechanism. We have used atomically detailed simulations to reveal the structural basis for ligand binding and consequent functional dynamics of MD-1 and the RP105 complex. We rationalize reports of endogenous phospholipid binding, by showing that they prevent collapse of the malleable MD-1 fold, before refining crystallographic models and uncovering likely binding modes for LPS analogs. Subsequent binding affinity calculations reveal that endotoxin specificity arises from the entropic cost of expanding the MD-1 cavity to accommodate bulky lipid tails, and support the role of MD-1 as a "sink" that sequesters endotoxin from TLR4 and stabilizes RP105/TLR4 interactions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Multiple [3H]imipramine binding sites in brains of male and female Fawn-Hooded and Long-Evans rats

International Nuclear Information System (INIS)

Ieni, J.R.; Zukin, S.R.; Praag, H.M. van; Tobach, E.; Barr, G.A.

1985-01-01

Comparisons of high- and low-affinity [ 3 H]imipramine binding to whole brain homogenates from adult male and female rats of the Fawn-Hooded and Long-Evans strains were performed. Most strikingly, no significant differences were observed between the two strains in any of the binding parameters, indicating that brain [ 3 H]imipramine binding sites, which may be related to the serotonergic uptake process, appear normal in a strain of rats with serotonin platelet storage pool disease. However, a significant sex difference in high- but not low-affinity whole brain [ 3 H]imipramine Bsub(max) values was observed, with females of both strains having higher densities than males. (Auth.)

Effect of hypoxia on the incorporation of [2-3H] glycerol and [1-14C[-palmitate into lipids of various brain regions

International Nuclear Information System (INIS)

Alberghina, M.; Giuffrida, A.M.

1981-01-01

The lipid metabolism in guinea pig brain after intermittent hypoxia, prolonged for 80 hrs, was markedly impaired. The in vivo incorporation of [2-3H] glycerol and [1-14C] palmitate into lipids of microsomes, mitochondria, myelin, and synaptosomes, purified form cerebral hemispheres, was significantly lower in the hypoxic animals than in the controls. The same effect was observed on the incorporation of labeled precursors into lipids of mitochondria purified from cerebellum and brainstem. In particular, the labeling of th major phospholipids present - ie, phosphatidylcholine (PC) and phosphatidylethanolamine (PE) - in the mitochondria of the three brain regions examined decreased after hypoxic treatment

Alterations in substance P binding in brain nuclei of spontaneously hypertensive rats

International Nuclear Information System (INIS)

Shigematsu, K.; Niwa, M.; Kurihara, M.; Castren, E.; Saavedra, J.M.

1987-01-01

Substance P binding sites were characterized in brain nuclei of young (4-wk-old) and adult (16-wk-old) spontaneously hypertensive rats (SHR) and age-matched normotensive Wistar-Kyoto (WKY) control rats by quantitative autoradiography. Young SHR presented higher affinity constants (K/sub A/) than young WKY. The changes were restricted to locus coeruleus, the area postrema, the dorsal motor nucleus of the vagus, and to discrete areas located in lobes 9 and 10 of the vermis cerebelli of SHR. There were no differences in the maximal binding capacity (B/sub max/) except in the nucleus ambiguus where the B/sub max/ was lower than WKY. Conversely, the number of substance P binding sites was higher in the locus coeruleus, the nucleus tegmentalis dorsalis, the nucleus ambiguus, the dorsal motor nucleus of the vagus, the hypoglossal nucleus, the inferior olivary nucleus, and lobes 9 and 10 of the vermis cerebelli of adult SHR when compared with adult WKY. The results support the hypothesis of a role for brain substance P in blood pressure regulation and in genetic hypertension in rats

Characterization of [(3)H]harmane binding to rat whole brain membranes.

Science.gov (United States)

Anderson, N J; Robinson, E S J; Husbands, S M; Delagrange, P; Nutt, D J; Hudson, A L

2003-12-01

This study investigates the binding of [(3)H]harmane to rat whole brain homogenates. Saturation studies revealed [(3)H]harmane labels a single, saturable, high-capacity population with high affinity. All the test compounds displaced [(3)H]harmane completely and in an apparently monophasic manner. The displacement profile of the test ligands indicated labeling of MAO-A. Given the high level of MAO-A binding, it is unlikely that a low-capacity I(2) site would be distinguishable from the total [(3)H]harmane population.

Effect of antemortem and postmortem factors on [3H]MK-801 binding in the human brain: Transient elevation during early childhood

International Nuclear Information System (INIS)

Kornhuber, J.; Mack-Burkhardt, F.; Konradi, C.; Fritze, J.; Riederer, P.

1989-01-01

The effect of a number of antemortem and postmortem factors on [ 3 H]MK-801 binding was investigated under equilibrium conditions in the frontal cortex of human brains of 38 controls. Binding values transiently increased during the early postnatal period reaching a maximum at the age of about 2 years. After age 10 years [ 3 H]MK-801 binding sites disappeared at 5.7% per decade. The storage time of brain tissue had a reducing effect on these binding sites. There was no effect of gender, brain weight or postmortem time interval and the binding sites were bilaterally symmetrically distributed in the frontal cortex

Bilirubin Binding to PPARα Inhibits Lipid Accumulation

Science.gov (United States)

Stec, David E.; John, Kezia; Trabbic, Christopher J.; Luniwal, Amarjit; Hankins, Michael W.; Baum, Justin

2016-01-01

Numerous clinical and population studies have demonstrated that increased serum bilirubin levels protect against cardiovascular and metabolic diseases such as obesity and diabetes. Bilirubin is a potent antioxidant, and the beneficial actions of moderate increases in plasma bilirubin have been thought to be due to the antioxidant effects of this bile pigment. In the present study, we found that bilirubin has a new function as a ligand for PPARα. We show that bilirubin can bind directly to PPARα and increase transcriptional activity. When we compared biliverdin, the precursor to bilirubin, on PPARα transcriptional activation to known PPARα ligands, WY 14,643 and fenofibrate, it showed that fenofibrate and biliverdin have similar activation properties. Treatment of 3T3-L1 adipocytes with biliverdin suppressed lipid accumulation and upregulated PPARα target genes. We treated wild-type and PPARα KO mice on a high fat diet with fenofibrate or bilirubin for seven days and found that both signal through PPARα dependent mechanisms. Furthermore, the effect of bilirubin on lowering glucose and reducing body fat percentage was blunted in PPARα KO mice. These data demonstrate a new function for bilirubin as an agonist of PPARα, which mediates the protection from adiposity afforded by moderate increases in bilirubin. PMID:27071062

Zinc in the prevention of Fe2initiated lipid and protein oxidation

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M. PAOLA ZAGO

2000-01-01

Full Text Available In the present study we characterized the capacity of zinc to protect lipids and proteins from Fe2+-initiated oxidative damage. The effects of zinc on lipid oxidation were investigated in liposomes composed of brain phosphatidylcholine (PC and phosphatidylserine (PS at a molar relationship of 60:40 (PC:PS, 60:40. Lipid oxidation was evaluated as the oxidation of cis-parinaric acid or as the formation of 2-thiobarbituric acid-reactive substances (TBARS. Zinc protected liposomes from Fe2+ (2.5-50 muM-supported lipid oxidation. However, zinc (50 muM did not prevent the oxidative inactivation of glutamine synthelase and glucose 6-phosphate dehydrogenase when rat brain superntants were oxidized in the presence of 5 muM Fe2+ and 0.5 mM H2O2 .We also studied the interactions of zinc with epicatechin in the prevention of liid oxidation in liposomes. The simulaneous addition of 0.5 muM epicatechin (EC and 50 muM zinc or EC separately. Zinc (50 muM also protecte liposomes from the stimulatory effect of aluminum on Fe2+-initiated lipid oxidation. Zinc could play an important role as an antioxidant in biological systems, replacing iron and other metals with pro-oxidant activity from binding sites and interacting with other components of the oxidant defense system.

Tailoring Lipid and Polymeric Nanoparticles as siRNA Carriers towards the Blood-Brain Barrier – from Targeting to Safe Administration

DEFF Research Database (Denmark)

Gomes, Maria João; Fernandes, Carlos; Martins, Susana

2017-01-01

. The interaction of modified nanoparticles with brain endothelial cells increased 3-fold compared to non-modified lipid nanoparticles, and 4-fold compared to non-modified PLGA nanoparticles, respectively. These nanosystems, which were also demonstrated to be safe for human brain endothelial cells, without...... and efficient delivery to its target, two different nanoparticles platforms, solid lipid (SLN) and poly-lactic-co-glycolic (PLGA) nanoparticles were used in this study. Polymeric PLGA nanoparticles were around 115 nm in size and had 50 % of siRNA association efficiency, while SLN presented 150 nm...

Spastin binds to lipid droplets and affects lipid metabolism.

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Chrisovalantis Papadopoulos

2015-04-01

Full Text Available Mutations in SPAST, encoding spastin, are the most common cause of autosomal dominant hereditary spastic paraplegia (HSP. HSP is characterized by weakness and spasticity of the lower limbs, owing to progressive retrograde degeneration of the long corticospinal axons. Spastin is a conserved microtubule (MT-severing protein, involved in processes requiring rearrangement of the cytoskeleton in concert to membrane remodeling, such as neurite branching, axonal growth, midbody abscission, and endosome tubulation. Two isoforms of spastin are synthesized from alternative initiation codons (M1 and M87. We now show that spastin-M1 can sort from the endoplasmic reticulum (ER to pre- and mature lipid droplets (LDs. A hydrophobic motif comprised of amino acids 57 through 86 of spastin was sufficient to direct a reporter protein to LDs, while mutation of arginine 65 to glycine abolished LD targeting. Increased levels of spastin-M1 expression reduced the number but increased the size of LDs. Expression of a mutant unable to bind and sever MTs caused clustering of LDs. Consistent with these findings, ubiquitous overexpression of Dspastin in Drosophila led to bigger and less numerous LDs in the fat bodies and increased triacylglycerol levels. In contrast, Dspastin overexpression increased LD number when expressed specifically in skeletal muscles or nerves. Downregulation of Dspastin and expression of a dominant-negative variant decreased LD number in Drosophila nerves, skeletal muscle and fat bodies, and reduced triacylglycerol levels in the larvae. Moreover, we found reduced amount of fat stores in intestinal cells of worms in which the spas-1 homologue was either depleted by RNA interference or deleted. Taken together, our data uncovers an evolutionarily conserved role of spastin as a positive regulator of LD metabolism and open up the possibility that dysfunction of LDs in axons may contribute to the pathogenesis of HSP.

[(3)H]-YM-09151-2 binding sites in human brain postmortem.

Science.gov (United States)

Marazziti, Donatella; Baroni, Stefano; Masala, Irene; Giannaccini, Gino; Betti, Laura; Palego, Lionella; Catena Dell'Osso, Mario; Consoli, Giorgio; Castagna, Maura; Lucacchini, Antonio

2009-12-01

The controversial and limited data on the distribution of dopamine (DA) receptors of type 4 (D(4)) in the human brain prompted us to explore their density and pharmacological characteristics in the prefrontal cortex, striatum and hippocampus, through a series of binding assays. Brain samples were taken during autopsy from seven subjects. Tissue homogenates were incubated with increasing concentration of [(3)H]-YM-09151-2, a D(2)-like receptor antagonist, and L-745,870 and/or sulpiride to define the non-specific binding, while PPAP was used to block sigma receptors. The results showed a low density of D(4) receptors in the hippocampus only, with a preponderance of D(2)/D(3) and sigma receptors in the prefrontal cortex and striatum. In conclusion, these findings underline that it is possible to label D(4) receptors by means of [(3)H]-YM-09151-2, provided that D(2), D(3) and sigma receptors are blocked.

Interaction of red pepper (Capsicum annum, Tepin) polyphenols with Fe(II)-induced lipid peroxidation in brain and liver

Energy Technology Data Exchange (ETDEWEB)

Oboh, G [Biochemistry Department, Federal University of Technology, Akure, Ondo State (Nigeria); [Departamento de Quimica, Universidade Federal de Santa Maria (UFSM), Campus Universitario - Camobi, Santa Maria RS (Brazil); [Abdus Salam International Centre for Theoretical Physics, Trieste (Italy)]. E-mail: goboh2001@yahoo.com; Rocha, J B.T. [Campus Universitario - Camobi, Santa Maria RS (Brazil)

2006-03-15

Polyphenols exhibit a wide range of biological effects because of their antioxidant properties. Several types of polyphenols (phenolic acids, hydrolyzable tannins, and flavonoids) show anticarcinogenic and antimutagenic effects. Comparative studies were carried on the protective ability of free and bound polyphenol extracts of red Capsicum annuum Tepin (CAT) on brain and liver - In vitro. Free polyphenols of red Capsicum annuum Tepin (CAT) were extracted with 80% acetone, while the bound polyphenols were extracted with ethyl acetate from acid and alkaline hydrolysis of the pepper residue from free polyphenols extract. The phenol content, Fe (II) chelating ability, OH radical scavenging ability and protective ability of the extract against Fe (II)-induced lipid peroxidation in brain and liver was subsequently determined. The results of the study revealed that the free polyphenols (218.2mg/100g) content of the pepper were significantly higher than the bound polyphenols (42.5mg/100g). Furthermore, the free polyphenol extract had a significantly higher (<0.05) Fe (II) chelating ability, OH radical scavenging ability than the bound polyphenols. In addition, both extracts significantly inhibited (P<0.05) basal and 25{mu}M Fe (II)- induced lipid peroxidation in Rat's brain and liver in a dose dependent. However, the free polyphenols caused a significantly higher inhibition in the MDA (Malondialdehyde) production in the brain and liver homogenates than the bound phenols. Furthermore, the polyphenols protected the liver more than the brain. In conclusion, free polyphenols from Capsicum annuum protects both the liver and brain from Fe{sup 2+} induced lipid peroxidation, and this is probably due to the higher Fe (II) chelating ability and OH radical scavenging ability of the free polyphenols from the pepper. (author)

Long-term reproducibility of in vivo measures of specific binding of radioligands in rat brain

Energy Technology Data Exchange (ETDEWEB)

Kilbourn, Michael R. E-mail: mkilbour@umich.edu

2004-07-01

The long-term reproducibility of measures of in vivo specific binding of radiolabeled forms of (+)-{alpha}-dihydrotetrabenazine (DTBZ) and d-threo-methylphenidate (MPH) in rat brain was examined. All studies were done using a consistent bolus plus infusion protocol and calculation of equilibrium distribution volume ratios (DVR). Over a period of eight years striatal DVR values for DTBZ binding to the vesicular monoamine transporter 2 (VMAT2) in young adult (8-10 wks old) rats showed very good reproducibility (3.62{+-}0.33, N=35). Equivalent values were obtained using either tritiated or carbon-11 labeled DTBZ, and were irrespective of sex of animals. Older animals (78 wks old) showed losses (-45%) of specific binding. Striatal binding of MPH to the dopamine transporter (DAT) showed a similar reproducibility over a five year period (DVR=2.17{+-}0.39, N=52), again irrespective of radionuclide or sex. These studies demonstrate that use of a consistent in vivo technique can provide reliable measures of specific binding of radioligands to high affinity sites in the rat brain.

Inhibition of [11C]mirtazapine binding by alpha2-adrenoceptor antagonists studied by positron emission tomography in living porcine brain

DEFF Research Database (Denmark)

Smith, Donald F; Dyve, Suzan; Minuzzi, Luciano

2006-01-01

Inhibition of [11C]mirtazapine binding by alpha2-adrenoceptor antagonists studied by positron emission tomography in living porcine brain......Inhibition of [11C]mirtazapine binding by alpha2-adrenoceptor antagonists studied by positron emission tomography in living porcine brain...

Avanti lipid tools: connecting lipids, technology, and cell biology.

Science.gov (United States)

Sims, Kacee H; Tytler, Ewan M; Tipton, John; Hill, Kasey L; Burgess, Stephen W; Shaw, Walter A

2014-08-01

Lipid research is challenging owing to the complexity and diversity of the lipidome. Here we review a set of experimental tools developed for the seasoned lipid researcher, as well as, those who are new to the field of lipid research. Novel tools for probing protein-lipid interactions, applications for lipid binding antibodies, enhanced systems for the cellular delivery of lipids, improved visualization of lipid membranes using gold-labeled lipids, and advances in mass spectrometric analysis techniques will be discussed. Because lipid mediators are known to participate in a host of signal transduction and trafficking pathways within the cell, a comprehensive lipid toolbox that aids the science of lipidomics research is essential to better understand the molecular mechanisms of interactions between cellular components. This article is part of a Special Issue entitled Tools to study lipid functions. Copyright © 2014. Published by Elsevier B.V.

Brain-targeted delivery of trans-activating transcriptor-conjugated magnetic PLGA/lipid nanoparticles.

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Xiangru Wen

Full Text Available Magnetic poly (D,L-lactide-co-glycolide (PLGA/lipid nanoparticles (MPLs were fabricated from PLGA, L-α-phosphatidylethanolamine (DOPE, 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-amino (polyethylene glycol (DSPE-PEG-NH2, and magnetic nanoparticles (NPs, and then conjugated to trans-activating transcriptor (TAT peptide. The TAT-MPLs were designed to target the brain by magnetic guidance and TAT conjugation. The drugs hesperidin (HES, naringin (NAR, and glutathione (GSH were encapsulated in MPLs with drug loading capacity (>10% and drug encapsulation efficiency (>90%. The therapeutic efficacy of the drug-loaded TAT-MPLs in bEnd.3 cells was compared with that of drug-loaded MPLs. The cells accumulated higher levels of TAT-MPLs than MPLs. In addition, the accumulation of QD-loaded fluorescein isothiocyanate (FITC-labeled TAT-MPLs in bEnd.3 cells was dose and time dependent. Our results show that TAT-conjugated MPLs may function as an effective drug delivery system that crosses the blood brain barrier to the brain.

β-chain of ATP synthase as a lipophorin binding protein and its role in lipid transfer in the midgut of Panstrongylus megistus (Hemiptera: Reduviidae).

Science.gov (United States)

Fruttero, Leonardo L; Demartini, Diogo R; Rubiolo, Edilberto R; Carlini, Célia R; Canavoso, Lilián E

2014-09-01

Lipophorin, the main lipoprotein in the circulation of the insects, cycles among peripheral tissues to exchange its lipid cargo at the plasma membrane of target cells, without synthesis or degradation of its apolipoprotein matrix. Currently, there are few characterized candidates supporting the functioning of the docking mechanism of lipophorin-mediated lipid transfer. In this work we combined ligand blotting assays and tandem mass spectrometry to characterize proteins with the property to bind lipophorin at the midgut membrane of Panstrongylus megistus, a vector of Chagas' disease. We further evaluated the role of lipophorin binding proteins in the transfer of lipids between the midgut and lipophorin. The β subunit of the ATP synthase complex (β-ATPase) was identified as a lipophorin binding protein. β-ATPase was detected in enriched midgut membrane preparations free of mitochondria. It was shown that β-ATPase partially co-localizes with lipophorin at the plasma membrane of isolated enterocytes and in the sub-epithelial region of the midgut tissue. The interaction of endogenous lipophorin and β-ATPase was also demonstrated by co-immunoprecipitation assays. Blocking of β-ATPase significantly diminished the binding of lipophorin to the isolated enterocytes and to the midgut tissue. In vivo assays injecting the β-ATPase antibody significantly reduced the transfer of [(3)H]-diacylglycerol from the midgut to the hemolymph in insects fed with [9,10-(3)H]-oleic acid, supporting the involvement of lipophorin-β-ATPase association in the transfer of lipids. In addition, the β-ATPase antibody partially impaired the transfer of fatty acids from lipophorin to the midgut, a less important route of lipid delivery to this tissue. Taken together, the findings strongly suggest that β-ATPase plays a role as a docking lipophorin receptor at the midgut of P. megistus. Copyright © 2014 Elsevier Ltd. All rights reserved.

Restoration of dietary-fat induced blood–brain barrier dysfunction by anti-inflammatory lipid-modulating agents

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Pallebage-Gamarallage Menuka

2012-09-01

Full Text Available Abstract Background Several studies have identified use of non-steroidal-anti-inflammatory drugs and statins for prevention of dementia, but their efficacy in slowing progression is not well understood. Cerebrovascular disturbances are common pathological feature of Alzheimer’s disease. We previously reported chronic ingestion of saturated fatty acids (SFA compromises blood–brain barrier (BBB integrity resulting in cerebral extravasation of plasma proteins and inflammation. However, the SFA-induced parenchymal accumulation of plasma proteins could be prevented by co-administration of some cholesterol lowering agents. Restoration of BBB dysfunction is clinically relevant, so the purpose of this study was to explore lipid-lowering agents could reverse BBB disturbances induced by chronic ingestion of SFA’s. Methods Wild-type mice were fed an SFA diet for 12 weeks to induce BBB dysfunction, and then randomised to receive atorvastatin, pravastatin or ibuprofen in combination with the SFA-rich diet for 2 or 8 weeks. Abundance of plasma-derived immunoglobulin-G (IgG and amyloid-β enriched apolipoprotein (apo-B lipoproteins within brain parenchyme were quantified utilising immunofluorescence microscopy. Results Atorvastatin treatment for 2 and 8 weeks restored BBB integrity, indicated by a substantial reduction of IgG and apo B, particularly within the hippocampus. Pravastatin, a water-soluble statin was less effective than atorvastatin (lipid-soluble. Statin effects were independent of changes in plasma lipid homeostasis. Ibuprofen, a lipid-soluble cyclooxygenase inhibitor attenuated cerebral accumulation of IgG and apo B as effectively as atorvastatin. Our findings are consistent with the drug effects being independent of plasma lipid homeostasis. Conclusion Our findings suggest that BBB dysfunction induced by chronic ingestion of SFA is reversible with timely introduction and sustained treatment with agents that suppress inflammation.

Differences between high-affinity forskolin binding sites in dopamine-riche and other regions of rat brain

International Nuclear Information System (INIS)

Poat, J.A.; Cripps, H.E.; Iversen, L.L.

1988-01-01

Forskolin labelled with [ 3 H] bound to high- and low-affinity sites in the rat brain. The high-affinity site was discretely located, with highest densities in the striatum, nucleus accumbens, olfactory tubercule, substantia nigra, hippocampus, and the molecular layers of the cerebellum. This site did not correlate well with the distribution of adenylate cyclase. The high-affinity striatal binding site may be associated with a stimulatory guanine nucleotide-binding protein. Thus, the number of sites was increased by the addition of Mg 2+ and guanylyl imidodiphosphate. Cholera toxin stereotaxically injected into rat striatum increased the number of binding sites, and no further increase was noted following the subsequent addition of guanyl nucleotide. High-affinity forskolin binding sites in non-dopamine-rich brain areas (hippocampus and cerebullum) were modulated in a qualitatively different manner by guanyl nucleotides. In these areas the number of binding sites was significantly reduced by the addition of guanyl nucleotide. These results suggest that forskolin may have a potential role in identifying different functional/structural guanine nucleotide-binding proteins

Potential Adverse Effects of Prolonged Sevoflurane Exposure on Developing Monkey Brain: From Abnormal Lipid Metabolism to Neuronal Damage.

Science.gov (United States)

Liu, Fang; Rainosek, Shuo W; Frisch-Daiello, Jessica L; Patterson, Tucker A; Paule, Merle G; Slikker, William; Wang, Cheng; Han, Xianlin

2015-10-01

Sevoflurane is a volatile anesthetic that has been widely used in general anesthesia, yet its safety in pediatric use is a public concern. This study sought to evaluate whether prolonged exposure of infant monkeys to a clinically relevant concentration of sevoflurane is associated with any adverse effects on the developing brain. Infant monkeys were exposed to 2.5% sevoflurane for 9 h, and frontal cortical tissues were harvested for DNA microarray, lipidomics, Luminex protein, and histological assays. DNA microarray analysis showed that sevoflurane exposure resulted in a broad identification of differentially expressed genes (DEGs) in the monkey brain. In general, these genes were associated with nervous system development, function, and neural cell viability. Notably, a number of DEGs were closely related to lipid metabolism. Lipidomic analysis demonstrated that critical lipid components, (eg, phosphatidylethanolamine, phosphatidylserine, and phosphatidylglycerol) were significantly downregulated by prolonged exposure of sevoflurane. Luminex protein analysis indicated abnormal levels of cytokines in sevoflurane-exposed brains. Consistently, Fluoro-Jade C staining revealed more degenerating neurons after sevoflurane exposure. These data demonstrate that a clinically relevant concentration of sevoflurane (2.5%) is capable of inducing and maintaining an effective surgical plane of anesthesia in the developing nonhuman primate and that a prolonged exposure of 9 h resulted in profound changes in gene expression, cytokine levels, lipid metabolism, and subsequently, neuronal damage. Generally, sevoflurane-induced neuronal damage was also associated with changes in lipid content, composition, or both; and specific lipid changes could provide insights into the molecular mechanism(s) underlying anesthetic-induced neurotoxicity and may be sensitive biomarkers for the early detection of anesthetic-induced neuronal damage. Published by Oxford University Press on behalf of the

Minimizing the non-specific binding of nanoparticles to the brain enables active targeting of Fn14-positive glioblastoma cells.

Science.gov (United States)

Schneider, Craig S; Perez, Jimena G; Cheng, Emily; Zhang, Clark; Mastorakos, Panagiotis; Hanes, Justin; Winkles, Jeffrey A; Woodworth, Graeme F; Kim, Anthony J

2015-02-01

A major limitation in the treatment of glioblastoma (GBM), the most common and deadly primary brain cancer, is delivery of therapeutics to invading tumor cells outside of the area that is safe for surgical removal. A promising way to target invading GBM cells is via drug-loaded nanoparticles that bind to fibroblast growth factor-inducible 14 (Fn14), thereby potentially improving efficacy and reducing toxicity. However, achieving broad particle distribution and nanoparticle targeting within the brain remains a significant challenge due to the adhesive extracellular matrix (ECM) and clearance mechanisms in the brain. In this work, we developed Fn14 monoclonal antibody-decorated nanoparticles that can efficiently penetrate brain tissue. We show these Fn14-targeted brain tissue penetrating nanoparticles are able to (i) selectively bind to recombinant Fn14 but not brain ECM proteins, (ii) associate with and be internalized by Fn14-positive GBM cells, and (iii) diffuse within brain tissue in a manner similar to non-targeted brain penetrating nanoparticles. In addition, when administered intracranially, Fn14-targeted nanoparticles showed improved tumor cell co-localization in mice bearing human GBM xenografts compared to non-targeted nanoparticles. Minimizing non-specific binding of targeted nanoparticles in the brain may greatly improve the access of particulate delivery systems to remote brain tumor cells and other brain targets. Copyright © 2014 Elsevier Ltd. All rights reserved.

The interaction of substituted benzamides with brain benzodiazepine binding sites in vitro.

OpenAIRE

Horton, R. W.; Lowther, S.; Chivers, J.; Jenner, P.; Marsden, C. D.; Testa, B.

1988-01-01

1. The interaction of substituted benzamides with brain benzodiazepine (BDZ) binding sites was examined by their ability to displace [3H]-flunitrazepam ([3H]-FNM) from specific binding sites in bovine cortical membranes in vitro. 2. Clebopride, Delagrange 2674, Delagrange 2335 and BRL 20627 displayed concentration-dependent displacement of [3H]-FNM with IC50 values of 73 nM, 132 nM, 7.7 microM and 5.9 microM, respectively. Other substituted benzamides including metoclopramide, sulpiride, tiap...

Binding of Neurotransmitters to Lipid Membranes

DEFF Research Database (Denmark)

Peters, Günther H.J.; Werge, Mikkel; Elf-Lind, Maria Northved

2014-01-01

/ acetylated g-aminobutyrate (GABAneu) with a dipalmitoylphosphatidylcholine (DPPC) bilayer. This study was motivated by recent research results that suggested that neural transmission may also be affected by nonspecific interactions of NTs with the lipid matrix of the synaptic membrane. Our results revealed...... backbone of the phospholipids. It is surprising that hydrophilic solutes can deeply penetrate into the membrane pointing to the fact that membrane affinity is governed by specific interactions. Our MD simulations identified the salt-bridge between the primary amine of NTs and the lipid phosphate group...

Characterization of the binding of 3H-norzimeldine, a 5-HT uptake inhibitor, to rat brain homogenates

International Nuclear Information System (INIS)

Hall, H.

1984-01-01

The binding of radiolabelled norzimeldine, a potent selective 5-HT reuptake inhibitor, to rat brain homogenates is described. 3 H-Norzimeldine binds to a site with high affinity (Ksub(D) = 10.5 nM) in a saturable manner (Bsub(max) = 15.4 pmol/g wet weight in the cerebral cortex). The number of binding sites in the various regions of the brain parallels the capacity of the 5-HT reuptake mechanism. Drugs that inhibit the reuptake of 5-HT are also potent inhibitors of the 3 H-norzimeldine binding, as are the tricyclic antidepressants, which are non-specific inhibitors of the noradrenaline and the 5-HT reuptake. Lesioning experiments using DSP4 (a NA neurotoxin) and p-chloroamphetamine (a 5-HT neurotoxin) suggest that the binding site is located on the presynaptic 5-HT nerve terminal, although a small component of the binding may be to noradrenergic uptake sites as well.(author)

Interaction analysis of chimeric metal-binding green fluorescent protein and artificial solid-supported lipid membrane by quartz crystal microbalance and atomic force microscopy

International Nuclear Information System (INIS)

Prachayasittikul, Virapong; Na Ayudhya, Chartchalerm Isarankura; Hilterhaus, Lutz; Hinz, Andreas; Tantimongcolwat, Tanawut; Galla, Hans-Joachim

2005-01-01

Non-specific adsorption and specific interaction between a chimeric green fluorescent protein (GFP) carrying metal-binding region and the immobilized zinc ions on artificial solid-supported lipid membranes was investigated using the quartz crystal microbalance technique and the atomic force microscopy (AFM). Supported lipid bilayer, composed of octanethiol and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine/1,2-dioleoyl-sn-glycero-3-[N- (5-amino-1-carboxypentyl iminodiacetic acid)succinyl] (NTA-DOGS)-Zn 2+ , was formed on the gold electrode of quartz resonator (5 MHz). Binding of the chimeric GFP to zinc ions resulted in a rapid decrease of resonance frequency. Reversibility of the process was demonstrated via the removal of metal ions by EDTA. Nanoscale structural orientation of the chimeric GFP on the membrane was imaged by AFM. Association constant of the specific binding to metal ions was 2- to 3-fold higher than that of the non-specific adsorption, which was caused by the fluidization effect of the metal-chelating lipid molecules as well as the steric hindrance effect. This infers a possibility for a further development of biofunctionalized membrane. However, maximization is needed in order to attain closer advancement to a membrane-based sensor device

Serotonin 2A receptor agonist binding in the human brain with [C]Cimbi-36

DEFF Research Database (Denmark)

Ettrup, A.; da Cunha-Bang, S.; McMahon, Barry P.

2014-01-01

[C]Cimbi-36 was recently developed as a selective serotonin 2A (5-HT) receptor agonist radioligand for positron emission tomography (PET) brain imaging. Such an agonist PET radioligand may provide a novel, and more functional, measure of the serotonergic system and agonist binding is more likely ....... Thus, we here describe [C]Cimbi-36 as the first agonist PET radioligand to successfully image and quantify 5-HT receptors in the human brain.Journal of Cerebral Blood Flow & Metabolism advance online publication, 30 April 2014; doi:10.1038/jcbfm.2014.68....... than antagonist binding to reflect 5-HT levels in vivo. Here, we show data from a first-in-human clinical trial with [C]Cimbi-36. In 29 healthy volunteers, we found high brain uptake and distribution according to 5-HT receptors with [C]Cimbi-36 PET. The two-tissue compartment model using arterial input...

Omega-3 fatty acids, lipids, and apoE lipidation in Alzheimer's disease: a rationale for multi-nutrient dementia prevention.

Science.gov (United States)

Grimm, Marcus O W; Michaelson, Daniel M; Hartmann, Tobias

2017-11-01

In the last decade, it has become obvious that Alzheimer's disease (AD) is closely linked to changes in lipids or lipid metabolism. One of the main pathological hallmarks of AD is amyloid-β (Aβ) deposition. Aβ is derived from sequential proteolytic processing of the amyloid precursor protein (APP). Interestingly, both, the APP and all APP secretases are transmembrane proteins that cleave APP close to and in the lipid bilayer. Moreover, apoE4 has been identified as the most prevalent genetic risk factor for AD. ApoE is the main lipoprotein in the brain, which has an abundant role in the transport of lipids and brain lipid metabolism. Several lipidomic approaches revealed changes in the lipid levels of cerebrospinal fluid or in post mortem AD brains. Here, we review the impact of apoE and lipids in AD, focusing on the major brain lipid classes, sphingomyelin, plasmalogens, gangliosides, sulfatides, DHA, and EPA, as well as on lipid signaling molecules, like ceramide and sphingosine-1-phosphate. As nutritional approaches showed limited beneficial effects in clinical studies, the opportunities of combining different supplements in multi-nutritional approaches are discussed and summarized. Copyright © 2017 by the American Society for Biochemistry and Molecular Biology, Inc.

Biochemical studies of mouse brain tubulin: colchicine binding (DEAE-cellulose filter) assay and subunits (α and β) biosynthesis and degradation (in newborn brain)

International Nuclear Information System (INIS)

Tse, C.F.

1978-01-01

A DEAE-cellulose filter assay, measuring [ 3 H]colchicine bound to colchicine binding protein (CBP) absorbed on filter discs, has been modified to include lM sucrose in the incubation medium for complexing colchicine to CBP in samples before applying the samples to filter discs (single point assay). Due to the much greater stability of colchicine binding capacity in the presence of lM sucrose, multiple time-point assays and least squares linear regression analysis were not necessary for accurate determination of CBP in hybrid mouse brain at different stages of development. The highest concentrations of CBP were observed in the 160,000g supernatant and pellet of newborn brain homogenate. Further studies of the modified filter assay documented that the assay has an overall counting efficiency of 27.3%, that DEAE-cellulose filters bind and retain all tubulin in the assay samples, and that one molecule of colchicine binds approximately one molecule of tubulin dimer. Therefore, millimoles of colchicine bound per milligram total protein can be used to calculate tubulin content. With this technique tubulin content of brain supernatant was found to be 11.9% for newborn, and 7.15% for 11 month old mice. Quantitative densitometry was also used to measure mouse brain supernatant actin content for these two stages. In vivo synthesis and degradation rates of tubulin α and β subunits of two day mouse brain 100,000g supernatant were studied after intracerebral injection of [ 3 H]leucine. Quantitative changes of the ratio of tritium specific activities of tubulin α and β subunits with time were determined. The pattern of change was biphasic. During the first phase the ratio decreased; during the second phase the ratio increased continuously. An interpretation consistent with all the data in this study is that the α subunit is synthesized at a more rapid rate than the β subunit

Prion protein accumulation in lipid rafts of mouse aging brain.

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Federica Agostini

Full Text Available The cellular form of the prion protein (PrP(C is a normal constituent of neuronal cell membranes. The protein misfolding causes rare neurodegenerative disorders known as transmissible spongiform encephalopathies or prion diseases. These maladies can be sporadic, genetic or infectious. Sporadic prion diseases are the most common form mainly affecting aging people. In this work, we investigate the biochemical environment in which sporadic prion diseases may develop, focusing our attention on the cell membrane of neurons in the aging brain. It is well established that with aging the ratio between the most abundant lipid components of rafts undergoes a major change: while cholesterol decreases, sphingomyelin content rises. Our results indicate that the aging process modifies the compartmentalization of PrP(C. In old mice, this change favors PrP(C accumulation in detergent-resistant membranes, particularly in hippocampi. To confirm the relationship between lipid content changes and PrP(C translocation into detergent-resistant membranes (DRMs, we looked at PrP(C compartmentalization in hippocampi from acid sphingomyelinase (ASM knockout (KO mice and synaptosomes enriched in sphingomyelin. In the presence of high sphingomyelin content, we observed a significant increase of PrP(C in DRMS. This process is not due to higher levels of total protein and it could, in turn, favor the onset of sporadic prion diseases during aging as it increases the PrP intermolecular contacts into lipid rafts. We observed that lowering sphingomyelin in scrapie-infected cells by using fumonisin B1 led to a 50% decrease in protease-resistant PrP formation. This may suggest an involvement of PrP lipid environment in prion formation and consequently it may play a role in the onset or development of sporadic forms of prion diseases.

Kinetic analysis of transport and opioid receptor binding of [3H](-)-cyclofoxy in rat brain in vivo: Implications for human studies

International Nuclear Information System (INIS)

Sawada, Y.; Kawai, R.; McManaway, M.; Otsuki, H.; Rice, K.C.; Patlak, C.S.; Blasberg, R.G.

1991-01-01

[3H]Cyclofoxy (CF: 17-cyclopropylmethyl-3,14-dihydroxy-4,5-alpha-epoxy-6-beta-fluoromorp hinan) is an opioid antagonist with affinity to both mu and kappa subtypes that was synthesized for quantitative evaluation of opioid receptor binding in vivo. Two sets of experiments in rats were analyzed. The first involved determining the metabolite-corrected blood concentration and tissue distribution of CF in brain 1 to 60 min after i.v. bolus injection. The second involved measuring brain washout for 15 to 120 s following intracarotid artery injection of CF. A physiologically based model and a classical compartmental pharmacokinetic model were compared. The models included different assumptions for transport across the blood-brain barrier (BBB); estimates of nonspecific tissue binding and specific binding to a single opiate receptor site were found to be essentially the same with both models. The nonspecific binding equilibrium constant varied modestly in different brain structures (Keq = 3-9), whereas the binding potential (BP) varied over a much broader range (BP = 0.6-32). In vivo estimates of the opioid receptor dissociation constant were similar for different brain structures (KD = 2.1-5.2 nM), whereas the apparent receptor density (Bmax) varied between 1 (cerebellum) and 78 (thalamus) pmol/g of brain. The receptor dissociation rate constants in cerebrum (k4 = 0.08-0.16 min-1; koff = 0.16-0.23 min-1) and brain vascular permeability (PS = 1.3-3.4 ml/min/g) are sufficiently high to achieve equilibrium conditions within a reasonable period of time. Graphical analysis of the data is inappropriate due to the high tissue-loss rate constant for CF in brain. From these findings, CF should be a very useful opioid receptor ligand for the estimation of the receptor binding parameters in human subjects using [18F]CF and positron emission tomography

Evaluation of the binding of the radiolabeled antidepressant drug, 18F-fluoxetine in the rodent brain: an in vitro and in vivo study

International Nuclear Information System (INIS)

Mukherjee, Jogeshwar; Das, Malay K.; Yang Zhiying; Lew, Robert

1998-01-01

We have developed 18 F-fluoxetine as a radiotracer analog of the antidepressant drug fluoxetine (Prozac). In vitro saturation experiments of 18 F-fluoxetine were carried out on rat midbrain tissue and citalopram was used for measuring nonspecific binding. A saturation curve for the binding of 18 F-fluoxetine was not obtained. Even when fluoxetine (10 μM) was used for measurements of nonspecific binding, a saturation curve was difficult to obtain. Other compounds, such as deprenyl, clorgyline, amphetamine, and reserpine were also not able to reduce the binding of 18 F-fluoxetine. Ex vivo autoradiographic experiments with 18 F-fluoxetine did not reveal any specific uptake in various brain regions. In vivo administration of 18 F-fluoxetine in rats showed similar uptake in all the brain regions with little regional selectivity. A subcellular analysis of rat brain tissue after intravenous (IV) administration of 18 F-fluoxetine indicated significant amounts of binding in mitochondria and synaptosomes. In summary, in vitro experiments with 18 F-fluoxetine indicate little specific binding. Binding to the serotonin transporter was not identifiable. High nonspecific binding of the tracer resulting from its subcellular nature in the brain masks the ability to detect binding to the serotonin uptake sites in vivo. These findings indicate that a large portion of the binding of 18 F-fluoxetine in rat brains is subcellular and clears slowly out of the cells. Other sites, such as monoamine oxidase, may also play a significant role in the action of fluoxetine

A strategy for increasing the brain uptake of a radioligand in animals: use of a drug that inhibits plasma protein binding

International Nuclear Information System (INIS)

Haradahira, Terushi; Zhang, Ming-Rong; Maeda, Jun; Okauchi, Takashi; Kawabe, Kouichi; Kida, Takayo; Suzuki, Kazutoshi; Suhara, Tetsuya

2000-01-01

A positron-emitter labeled radioligand for the glycine-binding site of the N-methyl-D-aspartate (NMDA) receptor, [ 11 C]L-703,717, was examined for its ability to penetrate the brain in animals by simultaneous use with drugs having high-affinity separate binding sites on human serum albumin. [ 11 C]L-703,717 has poor blood-brain barrier (BBB) permeability because it binds tightly to plasma proteins. Co-injection of warfarin (50-200 mg/kg), a drug that binds to albumin and resembles L-703,717 in structure, dose-dependently enhanced the penetration by [ 11 C]L-703,717 in mice, resulting in a five-fold increase in the brain radioactivity at 1 min after the injection. Drugs structurally unrelated to L-703,717, salicylate, phenol red, and L-tryptophan, were less effective or ineffective in increasing the uptake of [ 11 C]L-703,717. These results suggest that the simultaneous use of a drug that inhibits the binding of a radioligand to plasma proteins is a useful way to overcome the poor BBB permeability of the radioligand triggered by its tight binding to plasma proteins. In brain distribution studies in rodents, it was found that, after the increase in brain uptake with warfarin, much of the glycine site antagonist accumulates in the cerebellum but its pharmacological specificity did not match the glycine site of NMDA receptors

Receptor macroautoradiography of 3H-spiroperidol binding in rat brain

International Nuclear Information System (INIS)

Mori, Hirofumi; Shiba, Kazuhiro; Tsuji, Shiro; Matsuda, Hiroshi; Hisada, Kinichi; Kojima, Kazuhiko

1985-01-01

The kinetic and pharmacological characteristics of 3 H-spiroperidol binding sites were studied in slide mounted sections of rat forebrain, and optical binding conditions were defined. Using the receptor macroautoradiographic techniques with tritium-sensitive LKB sheet film, the distribution of dopamine (D 2 ) receptor was determined in slices including striatum of rat brain. The autoradiograms were analyzed using Video Digitizer System combined with video camera and minicomputer, and the subtraction images were obtained. These studies suggest that this quantitative receptor macroautoradiography might be useful in the explanation of etiology in the field of neuro-psychiatric diseases and the fundamental studies of positron emission computed tomography, since this method has several advantages over in vivo autoradiography and in vitro receptor assay. (author)

Modification by oxazepam of the diurnal variations in brain 125I-melatonin binding sites in sham-operated and pinealectomized rats

International Nuclear Information System (INIS)

Anis, Y.; Zisapel, N.; Nir, I.; Schmidt, U.

1992-01-01

Sham-operated and pinealectomized male rats were maintained at 14 h light: 10 h dark cycles (lights-on 5.00 h) and injected daily, for 14 days, with oxazepam or vehicle. 125 I-melatonin binding was recorded in synaptosomes prepared at 10.00, 18.00, and 24.00 h from the hypothalamus, hippocampus and medulla-pons of the rats. In the sham-operated, vehicle treated rats, specific 125 I-melatonin binding in all brain areas studied was higher at 18.00 h, whereas in the oxazepam-treated animals, binding was higher at 24.00 h than at the other times tested. In the pinealectomized, vehicle-treated rats, the binding recorded at 18.00 h in all three brain areas, was lower than at the other times of day tested. Oxazepam treatment decreased 125 I-melatonin binding at 24.00 h in the hippocampus and medulla-pons of the pinealectomized rats and did not significantly affect the binding in the hypothalamus. These results indicate the ability of oxazepam, pinealectomy and their combination, to manipulate the diurnal variations in 125 I-melatonin binding sites in the rat brain

Poly(amidoamine) dendrimers on lipid bilayers II: Effects of bilayer phase and dendrimer termination.

Science.gov (United States)

Kelly, Christopher V; Leroueil, Pascale R; Orr, Bradford G; Banaszak Holl, Mark M; Andricioaei, Ioan

2008-08-07

The molecular structures and enthalpy release of poly(amidoamine) (PAMAM) dendrimers binding to 1,2-dimyristoyl- sn-glycero-3-phosphocholine (DMPC) bilayers were explored through atomistic molecular dynamics. Three PAMAM dendrimer terminations were examined: protonated primary amine, neutral acetamide, and deprotonated carboxylic acid. Fluid and gel lipid phases were examined to extract the effects of lipid tail mobility on the binding of generation-3 dendrimers, which are directly relevant to the nanoparticle interactions involving lipid rafts, endocytosis, lipid removal, and/or membrane pores. Upon binding to gel phase lipids, dendrimers remained spherical, had a constant radius of gyration, and approximately one-quarter of the terminal groups were in close proximity to the lipids. In contrast, upon binding to fluid phase bilayers, dendrimers flattened out with a large increase in their asphericity and radii of gyration. Although over twice as many dendrimer-lipid contacts were formed on fluid versus gel phase lipids, the dendrimer-lipid interaction energy was only 20% stronger. The greatest enthalpy release upon binding was between the charged dendrimers and the lipid bilayer. However, the stronger binding to fluid versus gel phase lipids was driven by the hydrophobic interactions between the inner dendrimer and lipid tails.

Characterization of the binding of /sup 3/H-norzimeldine, a 5-HT uptake inhibitor, to rat brain homogenates

Energy Technology Data Exchange (ETDEWEB)

Hall, H. (Department of Biochemical Neuropharmacology, Research and Development Laboratories, Astra Laekemedel, Soedertaelje, Sweden)

1984-01-01

The binding of radiolabelled norzimeldine, a potent selective 5-HT reuptake inhibitor, to rat brain homogenates is described. /sup 3/H-Norzimeldine binds to a site with high affinity (Ksub(D) = 10.5 nM) in a saturable manner (Bsub(max) = 15.4 pmol/g wet weight in the cerebral cortex). The number of binding sites in the various regions of the brain parallels the capacity of the 5-HT reuptake mechanism. Drugs that inhibit the reuptake of 5-HT are also potent inhibitors of the /sup 3/H-norzimeldine binding, as are the tricyclic antidepressants, which are non-specific inhibitors of the noradrenaline and the 5-HT reuptake. Lesioning experiments using DSP4 (a NA neurotoxin) and p-chloroamphetamine (a 5-HT neurotoxin) suggest that the binding site is located on the presynaptic 5-HT nerve terminal, although a small component of the binding may be to noradrenergic uptake sites as well.

Metformin reduces lipid accumulation in macrophages by inhibiting FOXO1-mediated transcription of fatty acid-binding protein 4

International Nuclear Information System (INIS)

Song, Jun; Ren, Pingping; Zhang, Lin; Wang, Xing Li; Chen, Li; Shen, Ying H.

2010-01-01

Objective: The accumulation of lipids in macrophages contributes to the development of atherosclerosis. Strategies to reduce lipid accumulation in macrophages may have therapeutic potential for preventing and treating atherosclerosis and cardiovascular complications. The antidiabetic drug metformin has been reported to reduce lipid accumulation in adipocytes. In this study, we examined the effects of metformin on lipid accumulation in macrophages and investigated the mechanisms involved. Methods and results: We observed that metformin significantly reduced palmitic acid (PA)-induced intracellular lipid accumulation in macrophages. Metformin promoted the expression of carnitine palmitoyltransferase I (CPT-1), while reduced the expression of fatty acid-binding protein 4 (FABP4) which was involved in PA-induced lipid accumulation. Quantitative real-time PCR showed that metformin regulates FABP4 expression at the transcriptional level. We identified forkhead transcription factor FOXO1 as a positive regulator of FABP4 expression. Inhibiting FOXO1 expression with FOXO1 siRNA significantly reduced basal and PA-induced FABP4 expression. Overexpression of wild-type FOXO1 and constitutively active FOXO1 significantly increased FABP4 expression, whereas dominant negative FOXO1 dramatically decreased FABP4 expression. Metformin reduced FABP4 expression by promoting FOXO1 nuclear exclusion and subsequently inhibiting its activity. Conclusions: Taken together, these results suggest that metformin reduces lipid accumulation in macrophages by repressing FOXO1-mediated FABP4 transcription. Thus, metformin may have a protective effect against lipid accumulation in macrophages and may serve as a therapeutic agent for preventing and treating atherosclerosis in metabolic syndrome.

Metformin reduces lipid accumulation in macrophages by inhibiting FOXO1-mediated transcription of fatty acid-binding protein 4

Energy Technology Data Exchange (ETDEWEB)

Song, Jun [Qilu Hospital, Shandong University, Jinan, Shandong (China); Division of Cardiothoracic Surgery, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX (United States); Texas Heart Institute at St. Luke' s Episcopal Hospital, Houston, TX (United States); Ren, Pingping; Zhang, Lin [Division of Cardiothoracic Surgery, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX (United States); Texas Heart Institute at St. Luke' s Episcopal Hospital, Houston, TX (United States); Wang, Xing Li [Qilu Hospital, Shandong University, Jinan, Shandong (China); Division of Cardiothoracic Surgery, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX (United States); Texas Heart Institute at St. Luke' s Episcopal Hospital, Houston, TX (United States); Chen, Li [Qilu Hospital, Shandong University, Jinan, Shandong (China); Shen, Ying H., E-mail: hyshen@bcm.edu [Division of Cardiothoracic Surgery, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX (United States); Texas Heart Institute at St. Luke' s Episcopal Hospital, Houston, TX (United States)

2010-02-26

Objective: The accumulation of lipids in macrophages contributes to the development of atherosclerosis. Strategies to reduce lipid accumulation in macrophages may have therapeutic potential for preventing and treating atherosclerosis and cardiovascular complications. The antidiabetic drug metformin has been reported to reduce lipid accumulation in adipocytes. In this study, we examined the effects of metformin on lipid accumulation in macrophages and investigated the mechanisms involved. Methods and results: We observed that metformin significantly reduced palmitic acid (PA)-induced intracellular lipid accumulation in macrophages. Metformin promoted the expression of carnitine palmitoyltransferase I (CPT-1), while reduced the expression of fatty acid-binding protein 4 (FABP4) which was involved in PA-induced lipid accumulation. Quantitative real-time PCR showed that metformin regulates FABP4 expression at the transcriptional level. We identified forkhead transcription factor FOXO1 as a positive regulator of FABP4 expression. Inhibiting FOXO1 expression with FOXO1 siRNA significantly reduced basal and PA-induced FABP4 expression. Overexpression of wild-type FOXO1 and constitutively active FOXO1 significantly increased FABP4 expression, whereas dominant negative FOXO1 dramatically decreased FABP4 expression. Metformin reduced FABP4 expression by promoting FOXO1 nuclear exclusion and subsequently inhibiting its activity. Conclusions: Taken together, these results suggest that metformin reduces lipid accumulation in macrophages by repressing FOXO1-mediated FABP4 transcription. Thus, metformin may have a protective effect against lipid accumulation in macrophages and may serve as a therapeutic agent for preventing and treating atherosclerosis in metabolic syndrome.

Mixed bilayer containing dipalmitoylphosphatidylcholine and dipalmitoylphosphatidylserine: lipid complexation, ion binding, and electrostatics.

Science.gov (United States)

Pandit, Sagar A; Bostick, David; Berkowitz, Max L

2003-11-01

Two mixed bilayers containing dipalmitoylphosphatidylcholine and dipalmitoylphosphatidylserine at a ratio of 5:1 are simulated in NaCl electrolyte solutions of different concentration using the molecular dynamics technique. Direct NH.O and CH.O hydrogen bonding between lipids was observed to serve as the basis of interlipid complexation. It is deduced from our results and previous studies that dipalmitoylphosphatidylcholine alone is less likely to form interlipid complexes than in the presence of bound ions or other bilayer "impurities" such as dipalmitoylphosphatidylserine. The binding of counterions is observed and quantitated. Based upon the calculated ion binding constants, the Gouy-Chapman surface potential (theta) is calculated. In addition we calculated the electrostatic potential profile (Phi) by twice integrating the system charge distribution. A large discrepancy between and the value of Phi at the membrane surface is observed. However, at "larger" distance from the bilayer surface, a qualitative similarity in the z-profiles of Phi and psi(GC) is seen. The discrepancy between the two potential profiles near the bilayer surface is attributed to the discrete and nonbulk-like nature of water in the interfacial region and to the complex geometry of this region.

Quantitative autoradiography of the binding sites for [125I] iodoglyburide, a novel high-affinity ligand for ATP-sensitive potassium channels in rat brain

International Nuclear Information System (INIS)

Gehlert, D.R.; Gackenheimer, S.L.; Mais, D.E.; Robertson, D.W.

1991-01-01

We have developed a high specific activity ligand for localization of ATP-sensitive potassium channels in the brain. When brain sections were incubated with [ 125 I]iodoglyburide (N-[2-[[[(cyclohexylamino)carbonyl]amino]sulfonyl]ethyl]-5- 125 I-2- methoxybenzamide), the ligand bound to a single site with a KD of 495 pM and a maximum binding site density of 176 fmol/mg of tissue. Glyburide was the most potent inhibitor of specific [ 125 I]iodoglyburide binding to rat forebrain sections whereas iodoglyburide and glipizide were slightly less potent. The binding was also sensitive to ATP which completely inhibited binding at concentrations of 10 mM. Autoradiographic localization of [ 125 I]iodoglyburide binding indicated a broad distribution of the ATP-sensitive potassium channel in the brain. The highest levels of binding were seen in the globus pallidus and ventral pallidum followed by the septohippocampal nucleus, anterior pituitary, the CA2 and CA3 region of the hippocampus, ventral pallidum, the molecular layer of the cerebellum and substantia nigra zona reticulata. The hilus and dorsal subiculum of the hippocampus, molecular layer of the dentate gyrus, cerebral cortex, lateral olfactory tract nucleus, olfactory tubercle and the zona incerta contained relatively high levels of binding. A lower level of binding (approximately 3- to 4-fold) was found throughout the remainder of the brain. These results indicate that the ATP-sensitive potassium channel has a broad presence in the rat brain and that a few select brain regions are enriched in this subtype of neuronal potassium channels

The kinetics of specific [3H]flunitrazepam ([3H]FNZ) binding in the brain of the epaulette shark (hemiscyllium ocellatum)

International Nuclear Information System (INIS)

Wise, G.; Renshaw, G.M.C.; Dodd, P.R.

1998-01-01

Full text: We have previously established that the epaulette shark is tolerant to hypoxia and that the resulting brain hypometabolism appears to be correlated with increased levels of GABA. It is of interest to determine whether there is a change in GABA A receptor number and/or binding characteristics in response to hypoxia. The focus of this initial study is to determine the kinetics of [ 3 H]FNZ binding to the benzodiazapine binding site on the GABA A receptor in the brain, so that the effect of hypoxia on GABA A receptors can be determined. Adult epaulette sharks were anaesthetised with 80mg/L of MS222 and the brain was dissected and rapidly frozen. Membranes were prepared at 4 deg C by homogenising the dissected tissue in 0.32M sucrose and centrifuging the homogenate for 10 min at 6 000g. The supernatant was layered onto an aliquat of 0.8M sucrose then centrifuged for 30 min at 40 000g. After washing the membranes, the binding characteristics of [ 3 H]FNZ were examined using in vitro centrifugation assays. This method revealed that [ 3 H]FNZ bound specifically to low-affinity binding sites in an elasmobranch brain. This finding is in contrast with previous reports of little to no specific binding of [ 3 H]FNZ in elasmobranchs, which precluded an estimation of binding parameters. Copyright (1998) Australian Neuroscience Society

Characterization of kappa 1 and kappa 2 opioid binding sites in frog (Rana esculenta) brain membrane preparation

Energy Technology Data Exchange (ETDEWEB)

Benyhe, S.; Varga, E.; Hepp, J.; Magyar, A.; Borsodi, A.; Wollemann, M.

1990-09-01

The distribution and properties of frog brain kappa-opioid receptor subtypes differ not only from those of the guinea pig brain, but also from that of the rat brain. In guinea pig cerebellum the kappa 1 is the dominant receptor subtype, frog brain contains mainly the kappa 2 subtype, and the distribution of the rat brain subtypes is intermediate between the two others. In competition experiments it has been established that ethylketocyclazocine and N-cyclopropylmethyl-norazidomorphine, which are nonselective kappa-ligands, have relatively high affinities to frog brain membranes. The kappa 2 ligands (Met5)enkephalin-Arg6-Phe7 and etorphine also show high affinities to the frog brain. Kappa 1 binding sites measured in the presence of 5 microM/D-Ala2-Leu5/enkephalin represent 25-30% of (3H)ethylketocyclazocine binding in frog brain membranes. The kappa 2 subtype in frog brain resembles more to the mu subtype than the delta subtype of opioid receptors, but it differs from the mu subtype in displaying low affinity toward beta-endorphin and /D-Ala2-(Me)Phe4-Gly5-ol/enkephalin (DAGO). From our data it is evident that the opioid receptor subtypes are already present in the amphibian brain but the differences among them are less pronounced than in mammalian brain.

Characterization of kappa 1 and kappa 2 opioid binding sites in frog (Rana esculenta) brain membrane preparation

International Nuclear Information System (INIS)

Benyhe, S.; Varga, E.; Hepp, J.; Magyar, A.; Borsodi, A.; Wollemann, M.

1990-01-01

The distribution and properties of frog brain kappa-opioid receptor subtypes differ not only from those of the guinea pig brain, but also from that of the rat brain. In guinea pig cerebellum the kappa 1 is the dominant receptor subtype, frog brain contains mainly the kappa 2 subtype, and the distribution of the rat brain subtypes is intermediate between the two others. In competition experiments it has been established that ethylketocyclazocine and N-cyclopropylmethyl-norazidomorphine, which are nonselective kappa-ligands, have relatively high affinities to frog brain membranes. The kappa 2 ligands (Met5)enkephalin-Arg6-Phe7 and etorphine also show high affinities to the frog brain. Kappa 1 binding sites measured in the presence of 5 microM/D-Ala2-Leu5/enkephalin represent 25-30% of [3H]ethylketocyclazocine binding in frog brain membranes. The kappa 2 subtype in frog brain resembles more to the mu subtype than the delta subtype of opioid receptors, but it differs from the mu subtype in displaying low affinity toward beta-endorphin and /D-Ala2-(Me)Phe4-Gly5-ol/enkephalin (DAGO). From our data it is evident that the opioid receptor subtypes are already present in the amphibian brain but the differences among them are less pronounced than in mammalian brain

Polyunsaturated fatty acids synergize with lipid droplet binding thalidomide analogs to induce oxidative stress in cancer cells

Directory of Open Access Journals (Sweden)

Madácsi Ramóna

2010-06-01

Full Text Available Abstract Background Cytoplasmic lipid-droplets are common inclusions of eukaryotic cells. Lipid-droplet binding thalidomide analogs (2,6-dialkylphenyl-4/5-amino-substituted-5,6,7-trifluorophthalimides with potent anticancer activities were synthesized. Results Cytotoxicity was detected in different cell lines including melanoma, leukemia, hepatocellular carcinoma, glioblastoma at micromolar concentrations. The synthesized analogs are non-toxic to adult animals up to 1 g/kg but are teratogenic to zebrafish embryos at micromolar concentrations with defects in the developing muscle. Treatment of tumor cells resulted in calcium release from the endoplasmic reticulum (ER, induction of reactive oxygen species (ROS, ER stress and cell death. Antioxidants could partially, while an intracellular calcium chelator almost completely diminish ROS production. Exogenous docosahexaenoic acid or eicosapentaenoic acid induced calcium release and ROS generation, and synergized with the analogs in vitro, while oleic acid had no such an effect. Gene expression analysis confirmed the induction of ER stress-mediated apoptosis pathway components, such as GADD153, ATF3, Luman/CREB3 and the ER-associated degradation-related HERPUD1 genes. Tumor suppressors, P53, LATS2 and ING3 were also up-regulated in various cell lines after drug treatment. Amino-phthalimides down-regulated the expression of CCL2, which is implicated in tumor metastasis and angiogenesis. Conclusions Because of the anticancer, anti-angiogenic action and the wide range of applicability of the immunomodulatory drugs, including thalidomide analogs, lipid droplet-binding members of this family could represent a new class of agents by affecting ER-membrane integrity and perturbations of ER homeostasis.

The effect of deferoxamine on brain lipid peroxide levels and Na-K ATPase activity following experimental subarachnoid hemorrhage.

Science.gov (United States)

Bilgihan, A; Türközkan, N; Aricioğlu, A; Aykol, S; Cevik, C; Göksel, M

1994-05-01

1. In the present study we have studied the effects of deferoxamine treatment on lipid peroxidation and Na-K ATPase activity after experimental induction of subarachnoid haemorrhage (SAH) in guinea pigs. 2. We assessed the extent of lipid peroxidation by measuring the level of malondialdehyde and Na-K ATPase activity in 3 different groups (sham-operated, SAH, SAH + deferoxamine). 3. There was no significant difference in lipid peroxide content between sham-operated and haemorrhagic animals, but Na-K ATPase activity decreased after SAH. 4. Deferoxamine treatment reduced the malondialdehyde content and induced the recovery of Na-K ATPase activity, exerting a brain protective role against the detrimental effects of the haemorrhage.

Identifying lipidic emulsomes for improved oxcarbazepine brain targeting: In vitro and rat in vivo studies.

Science.gov (United States)

El-Zaafarany, Ghada M; Soliman, Mahmoud E; Mansour, Samar; Awad, Gehanne A S

2016-04-30

Lipid-based nanovectors offer effective carriers for brain delivery by improving drug potency and reducing off-target effects. Emulsomes are nano-triglyceride (TG) carriers formed of lipid cores supported by at least one phospholipid (PC) sheath. Due to their surface active properties, PC forms bilayers at the aqueous interface, thereby enabling encapsulated drug to benefit from better bioavailability and stability. Emulsomes of oxcarbazepine (OX) were prepared, aimed to offer nanocarriers for nasal delivery for brain targeting. Different TG cores (Compritol(®), tripalmitin, tristearin and triolein) and soya phosphatidylcholine in different amounts and ratios were used for emulsomal preparation. Particles were modulated to generate nanocarriers with suitable size, charge, encapsulation efficiency and prolonged release. Cytotoxicity and pharmacokinetic studies were also implemented. Nano-spherical OX-emulsomes with maximal encapsulation of 96.75% were generated. Stability studies showed changes within 30.6% and 11.2% in the size and EE% after 3 months. MTT assay proved a decrease in drug toxicity by its encapsulation in emulsomes. Incorporation of OX into emulsomes resulted in stable nanoformulations. Tailoring emulsomes properties by modulating the surface charge and particle size produced a stable system for the lipophilic drug with a prolonged release profile and mean residence time and proved direct nose-to-brain transport in rats. Copyright © 2016 Elsevier B.V. All rights reserved.

A strategy for increasing the brain uptake of a radioligand in animals: use of a drug that inhibits plasma protein binding

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Haradahira, Terushi E-mail: terushi@nirs.go.jp; Zhang, Ming-Rong; Maeda, Jun; Okauchi, Takashi; Kawabe, Kouichi; Kida, Takayo; Suzuki, Kazutoshi; Suhara, Tetsuya

2000-05-01

A positron-emitter labeled radioligand for the glycine-binding site of the N-methyl-D-aspartate (NMDA) receptor, [{sup 11}C]L-703,717, was examined for its ability to penetrate the brain in animals by simultaneous use with drugs having high-affinity separate binding sites on human serum albumin. [{sup 11}C]L-703,717 has poor blood-brain barrier (BBB) permeability because it binds tightly to plasma proteins. Co-injection of warfarin (50-200 mg/kg), a drug that binds to albumin and resembles L-703,717 in structure, dose-dependently enhanced the penetration by [{sup 11}C]L-703,717 in mice, resulting in a five-fold increase in the brain radioactivity at 1 min after the injection. Drugs structurally unrelated to L-703,717, salicylate, phenol red, and L-tryptophan, were less effective or ineffective in increasing the uptake of [{sup 11}C]L-703,717. These results suggest that the simultaneous use of a drug that inhibits the binding of a radioligand to plasma proteins is a useful way to overcome the poor BBB permeability of the radioligand triggered by its tight binding to plasma proteins. In brain distribution studies in rodents, it was found that, after the increase in brain uptake with warfarin, much of the glycine site antagonist accumulates in the cerebellum but its pharmacological specificity did not match the glycine site of NMDA receptors.

Kinetic analysis of transport and opioid receptor binding of ( sup 3 H)(-)-cyclofoxy in rat brain in vivo: Implications for human studies

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Sawada, Y.; Kawai, R.; McManaway, M.; Otsuki, H.; Rice, K.C.; Patlak, C.S.; Blasberg, R.G. (National Institutes of Health, Bethesda, MD (USA))

1991-03-01

(3H)Cyclofoxy (CF: 17-cyclopropylmethyl-3,14-dihydroxy-4,5-alpha-epoxy-6-beta-fluoromorp hinan) is an opioid antagonist with affinity to both mu and kappa subtypes that was synthesized for quantitative evaluation of opioid receptor binding in vivo. Two sets of experiments in rats were analyzed. The first involved determining the metabolite-corrected blood concentration and tissue distribution of CF in brain 1 to 60 min after i.v. bolus injection. The second involved measuring brain washout for 15 to 120 s following intracarotid artery injection of CF. A physiologically based model and a classical compartmental pharmacokinetic model were compared. The models included different assumptions for transport across the blood-brain barrier (BBB); estimates of nonspecific tissue binding and specific binding to a single opiate receptor site were found to be essentially the same with both models. The nonspecific binding equilibrium constant varied modestly in different brain structures (Keq = 3-9), whereas the binding potential (BP) varied over a much broader range (BP = 0.6-32). In vivo estimates of the opioid receptor dissociation constant were similar for different brain structures (KD = 2.1-5.2 nM), whereas the apparent receptor density (Bmax) varied between 1 (cerebellum) and 78 (thalamus) pmol/g of brain. The receptor dissociation rate constants in cerebrum (k4 = 0.08-0.16 min-1; koff = 0.16-0.23 min-1) and brain vascular permeability (PS = 1.3-3.4 ml/min/g) are sufficiently high to achieve equilibrium conditions within a reasonable period of time. Graphical analysis of the data is inappropriate due to the high tissue-loss rate constant for CF in brain. From these findings, CF should be a very useful opioid receptor ligand for the estimation of the receptor binding parameters in human subjects using (18F)CF and positron emission tomography.

Biochemical studies of mouse brain tubulin: colchicine binding (DEAE-cellulose filter) assay and subunits ( α and β) biosynthesis and degradation (in newborn brain)

Energy Technology Data Exchange (ETDEWEB)

Tse, Cek-Fyne [Univ. of Rochester, NY (United States)

1978-01-01

A DEAE-cellulose filter assay, measuring (³H)colchicine bound to colchicine binding protein (CBP) absorbed on filter discs, has been modified to include lM sucrose in the incubation medium for complexing colchicine to CBP in samples before applying the samples to filter discs (single point assay). Due to the much greater stability of colchicine binding capacity in the presence of lM sucrose, multiple time-point assays and least squares linear regression analysis were not necessary for accurate determination of CBP in hybrid mouse brain at different stages of development. The highest concentrations of CBP were observed in the 160,000g supernatant and pellet of newborn brain homogenate. Further studies of the modified filter assay documented that the assay has an overall counting efficiency of 27.3%, that DEAE-cellulose filters bind and retain all tubulin in the assay samples, and that one molecule of colchicine binds approximately one molecule of tubulin dimer. Therefore, millimoles of colchicine bound per milligram total protein can be used to calculate tubulin content. With this technique tubulin content of brain supernatant was found to be 11.9% for newborn, and 7.15% for 11 month old mice. Quantitative densitometry was also used to measure mouse brain supernatant actin content for these two stages. In vivo synthesis and degradation rates of tubulin ..cap alpha.. and ..beta.. subunits of two day mouse brain 100,000g supernatant were studied after intracerebral injection of (³H)leucine. Quantitative changes of the ratio of tritium specific activities of tubulin ..cap alpha.. and ..beta.. subunits with time were determined. The pattern of change was biphasic. During the first phase the ratio decreased; during the second phase the ratio increased continuously. An interpretation consistent with all the data in this study is that the ..cap alpha.. subunit is synthesized at a more rapid rate than the ..beta.. subunit. (ERB)

Myristoylated α subunits of guanine nucleotide-binding regulatory proteins

International Nuclear Information System (INIS)

Buss, J.E.; Mumby, S.M.; Casey, P.J.; Gilman, A.G.; Sefton, B.M.

1987-01-01

Antisera directed against specific subunits of guanine nucleotide-binding regulatory proteins (G proteins) were used to immunoprecipitate these polypeptides from metabolically labeled cells. This technique detects, in extracts of a human astrocytoma cell line, the α subunits of G/sub s/ (stimulatory) (α 45 and α 52 ), a 41-kDa subunit of G/sub i/ (inhibitory) (α 41 ), a 40-kDa protein (α 40 ), and the 36-kDa β subunit. No protein that comigrated with the α subunit of G 0 (unknown function) (α 39 ) was detected. In cells grown in the presence of [ 3 H]myristic acid, α 41 and α 40 contained 3 H label, while the β subunit did not. Chemical analysis of lipids attached covalently to purified α 41 and α 39 from bovine brain also revealed myristic acid. Similar analysis of brain G protein β and γ subunits and of G/sub t/ (Transducin) subunits (α, β, and γ) failed to reveal fatty acids. The fatty acid associated with α 41 , α 40 , and α 39 was stable to treatment with base, suggesting that the lipid is linked to the polypeptide via an amide bond. These GTP binding proteins are thus identified as members of a select group of proteins that contains myristic acid covalently attached to the peptide backbone. Myristate may play an important role in stabilizing interactions of G proteins with phospholipid or with membrane-bound proteins

Comparison of (/sup 125/I)beta-endorphin binding to rat brain and NG108-15 cells using a monoclonal antibody directed against the opioid receptor

Energy Technology Data Exchange (ETDEWEB)

Bidlack, J.M.; O' Malley, W.E.; Schulz, R.

1988-02-01

The properties of (/sup 125/I)beta h-endorphin-binding sites from rat brain membranes and membranes from the NG108-15 cell line were compared using a monoclonal antibody directed against the opioid receptor and opioid peptides as probes. The binding of (/sup 125/I)beta h-endorphin to both rat brain and NG108-15 membranes yielded linear Scatchard plots with Kd values of 1.2 nM and 1.5 nM, respectively, and Bmax values of 865 fmol/mg rat brain membrane protein and 1077 fmol/mg NG108-15 membrane protein. A monoclonal antibody, OR-689.2.4, capable of inhibiting mu and delta binding but not kappa binding to rat brain membranes, noncompetitively inhibited the binding of 1 nM (/sup 125/I)beta h-endorphin to rat brain and NG108-15 membranes with an IC50 value of 405 nM for rat brain membranes and 543 nM for NG108-15 membranes. The monoclonal antibody also inhibited the binding of 3 nM (/sup 3/H) (D-penicillamine2, D-penicillamine5) enkephalin to NG108-15 membranes with an IC50 value of 370 nM. In addition to blocking the binding of (/sup 125/I)beta h-endorphin to brain membranes, the antibody also displaced (/sup 125/I)beta h-endorphin from membranes. Site-specific opioid peptides had large variations in their IC50 values depending on whether they were inhibiting (/sup 125/I)beta h-endorphin binding to rat brain or the NG108-15 membranes. When the peptides were tested with the monoclonal antibody for their combined ability to inhibit (/sup 125/I)beta h-endorphin binding to both membrane preparations, the peptides and antibody blocked binding as though they were acting at allosterically coupled sites, not two totally independent sites. These studies suggest that mu-, delta-, and beta-endorphin-binding sites share some sequence homology with the 35,000-dalton protein that the antibody is directed against.

Quantitative in vivo detection of brain cell death after hypoxia ischemia using the lipid peak at 1.3 ppm of proton magnetic resonance spectroscopy in neonatal rats.

Science.gov (United States)

Ahn, So Yoon; Yoo, Hye Soo; Lee, Jang Hoon; Sung, Dong Kyung; Jung, Yu Jin; Sung, Se In; Lim, Keun Ho; Chang, Yun Sil; Lee, Jung Hee; Kim, Ki Soo; Park, Won Soon

2013-07-01

This study was performed to determine the accuracy of proton magnetic spectroscopy ((1)H-MRS) lipid peak as a noninvasive tool for quantitative in vivo detection of brain cell death. Seven day-old Sprague Dawley rats were subjected to 8% oxygen following a unilateral carotid artery ligation. For treatment, cycloheximide was given immediately after hypoxic ischemia (HI). Lipid peak was measured using (1)H-MRS at 24 hr after HI, and then brains were harvested for fluorocytometric analyses with annexin V/propidium iodide (PI) and fluorescent probe JC-1, and for adenosine-5'-triphosphate (ATP) and lactate. Increased lipid peak at 1.3 ppm measured with (1)H-MRS, apoptotic and necrotic cells, and loss of mitochondrial membrane potential (ΔΨ) at 24 hr after HI were significantly improved with cycloheximide treatment. Significantly reduced brain ATP and increased lactate levels observed at 24 hr after HI showed a tendency to improve without statistical significance with cycloheximide treatment. Lipid peak at 1.3 ppm showed significant positive correlation with both apoptotic and necrotic cells and loss of ΔΨ, and negative correlation with normal live cells. Lipid peak at 1.3 ppm measured by (1)H-MRS might be a sensitive and reliable diagnostic tool for quantitative in vivo detection of brain cell death after HI.

Influence of electromagnetic field (1800 MHz on lipid peroxidation in brain, blood, liver and kidney in rats

Directory of Open Access Journals (Sweden)

Paweł Bodera

2015-08-01

Full Text Available Objectives: The aim of this study is the evaluation of the influence of repeated (5 times for 15 min exposure to electromagnetic field (EMF of 1800 MHz frequency on tissue lipid peroxidation (LPO both in normal and inflammatory state, combined with analgesic treatment. Material and Methods: The concentration of malondialdehyde (MDA as the end-product of the lipid peroxidation (LPO was estimated in blood, liver, kidneys, and brain of Wistar rats, both healthy and those with complete Freund’s adjuvant (CFA-induced persistent paw inflammation. Results: The slightly elevated levels of the MDA in blood, kidney, and brain were observed among healthy rats in electromagnetic field (EMF-exposed groups, treated with tramadol (TRAM/EMF and exposed to the EMF. The malondialdehyde remained at the same level in the liver in all investigated groups: the control group (CON, the exposed group (EMF, treated with tramadol (TRAM as well as exposed to and treated with tramadol (TRAM/EMF. In the group of animals treated with the complete Freund’s adjuvant (CFA we also observed slightly increased values of the MDA in the case of the control group (CON and the exposed groups (EMF and TRAM/EMF. The MDA values concerning kidneys remained at the same levels in the control, exposed, and not-exposed group treated with tramadol. Results for healthy rats and animals with inflammation did not differ significantly. Conclusions: The electromagnetic field exposure (EMF, applied in the repeated manner together with opioid drug tramadol (TRAM, slightly enhanced lipid peroxidation level in brain, blood, and kidneys.

Inhibitory effect of magnesium sulfate on reaction of lipid hyperoxidation after radiation-induced acute brain injuries

International Nuclear Information System (INIS)

Wang Lili; Zhou Juying; Yu Zhiying; Qin Songbing; Xu Xiaoting; Li Li; Tu Yu

2007-01-01

Objective: To explore the protection of magnesium sulfate (MgSO 4 ) on radiation-induced acute brain injuries. Methods: 60 maturity Sprague-Dawley (SD) rats were randomly divided into 3 groups: blank control group, experimental control group and experimental-therapeutic group. The whole brain of SD rats of experimental control group and experimental-therapeutic group was irradiated to a dose of 20 Gy using 6 MeV electron. MgSO 4 was injected intraperitoneally into the rats of experimental-therapeutic group before and after irradiation for five times. At different time points ranging from the 1 d, 7 d, 14 d, 30 d after irradiation, the brain tissue were taken. The xanthine oxidase and colorimetric examination were used to measure the superoxide dismutase (SOD) and malonyldialdehyde (MDA) respectively in the rat brain respectively. Results: Compared with blank control group, the SOD in brain of experimental control group decreased significantly (P 4 used in early stage can inhibit the lipid peroxidation after radiation-induced acute brain injuries and alleviate the damage induced by free radicals to brain tissue. (authors)

Interaction between LSD and dopamine D2/3 binding sites in pig brain.

Science.gov (United States)

Minuzzi, Luciano; Nomikos, George G; Wade, Mark R; Jensen, Svend B; Olsen, Aage K; Cumming, Paul

2005-06-15

The psychoactive properties of the hallucinogen LSD have frequently been attributed to high affinity interactions with serotonin 5HT2 receptors in brain. Possible effects of LSD on dopamine D2/3 receptor availability have not previously been investigated in living brain. Therefore, we used PET to map the binding potential (pB) of [11C]raclopride in brain of three pigs, first in a baseline condition, and again at 1 and 4 h after administration of LSD (2.5 microg/kg, i.v.). There was a progressive treatment effect in striatum, where the pB was significantly reduced by 19% at 4 h after LSD administration. Concomitant maps of cerebral blood flow did not reveal significant changes in perfusion during this interval. Subsequent in vitro studies showed that LSD displaced [3H]raclopride (2 nM) from pig brain cryostat sections with an IC50 of 275 nM according to a one-site model. Fitting of a two-site model to the data suggested the presence of a component of the displacement curves with a subnanomolar IC50, comprising 20% of the total [3H]raclopride binding. In microdialysis experiments, LSD at similar and higher doses did not evoke changes in the interstitial concentration of dopamine or its acidic metabolites in rat striatum. Together, these results are consistent with a direct interaction between LSD and a portion of dopamine D2/3 receptors in pig brain, possibly contributing to the psychopharmacology of LSD. (c) 2005 Wiley-Liss, Inc.

Opiate antagonist binding sites in discrete brain regions of spontaneously hypertensive and normotensive Wistar-Kyoto rats

International Nuclear Information System (INIS)

Rahmani, N.H.; Gulati, A.; Bhargava, H.N.

1991-01-01

The binding of 3 H-naltrexone, an opiate receptor antagonist, to membranes of discrete brain regions and spinal cord of 10 week old spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto (WKY) rats was determined. The brain regions examined were hypothalamus, amygdala, hippocampus, corpus striatum, pons and medulla, midbrain and cortex. 3 H-Naltrexone bound to membranes of brain regions and spinal cord at a single high affinity site with an apparent dissociation constant value of 3 nM. The highest density of 3 H-naltrexone binding sites were in hippocampus and lowest in the cerebral cortex. The receptor density (B max value) and apparent dissociation constant (K d value) values of 3 H-naltrexone to bind to opiate receptors on the membranes of amygdala, hippocampus, corpus striatum, pons and medulla, midgrain, cortex and spinal cord of WKY and SHR rates did not differ. The B max value of 3 H-naltrexone binding to membranes of hypothalamus of SHR rates was 518% higher than WKY rats but the K d values in the two strains did not differ. It is concluded that SHR rats have higher density of opiate receptors labeled with 3 H-naltrexone in the hypothalamus only, in comparison with WKY rats, and that such a difference in the density of opiate receptors may be related to the elevated blood pressure in SHR rats

Quantitative localization of (/sup 3/H)TCP binding in rat brain by light microscopy autoradiography

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Sircar, R; Zukin, S R

1985-09-30

The anatomical localization of phencyclidine (PCP)/sigma-opiate receptors in rat brain was determined by quantitative light microscopy autoradiography using the new ligand N-(1-(2-thienyl) cyclohexyl(/sup 3/H) piperidine ((/sup 3/H)TCP). TCP is a potent analog of PCP which possesses a higher affinity for PCP/sigma-opiate receptor than does PCP itself. The highest level of (/sup 3/H)TCP binding was detected in the hippocampus. Intermediate levels were found in frontal cortex, striatum, amygdala and cerebellum. Specific (/sup 3/H)TCP binding was undetectable in anterior commissure and corpus callosum. The distribution pattern of (/sup 3/H)TCP binding sites is similar to the pattern obtained with (/sup 3/H)PCP but more sharply defined. On the basis of its greater potency and specificity, (/sup 3/H)TCP may prove superior to (/sup 3/H)PCP as a molecular probe for the study of brain sigma opiate/phencyclidine receptors. 13 refs.; 1 figure; 1 table.

Prevalence, specificity and determinants of lipid-interacting PDZ domains from an in-cell screen and in vitro binding experiments.

Directory of Open Access Journals (Sweden)

Ylva Ivarsson

Full Text Available BACKGROUND: PDZ domains are highly abundant protein-protein interaction modules involved in the wiring of protein networks. Emerging evidence indicates that some PDZ domains also interact with phosphoinositides (PtdInsPs, important regulators of cell polarization and signaling. Yet our knowledge on the prevalence, specificity, affinity, and molecular determinants of PDZ-PtdInsPs interactions and on their impact on PDZ-protein interactions is very limited. METHODOLOGY/PRINCIPAL FINDINGS: We screened the human proteome for PtdInsPs interacting PDZ domains by a combination of in vivo cell-localization studies and in vitro dot blot and Surface Plasmon Resonance (SPR experiments using synthetic lipids and recombinant proteins. We found that PtdInsPs interactions contribute to the cellular distribution of some PDZ domains, intriguingly also in nuclear organelles, and that a significant subgroup of PDZ domains interacts with PtdInsPs with affinities in the low-to-mid micromolar range. In vitro specificity for the head group is low, but with a trend of higher affinities for more phosphorylated PtdInsPs species. Other membrane lipids can assist PtdInsPs-interactions. PtdInsPs-interacting PDZ domains have generally high pI values and contain characteristic clusters of basic residues, hallmarks that may be used to predict additional PtdInsPs interacting PDZ domains. In tripartite binding experiments we established that peptide binding can either compete or cooperate with PtdInsPs binding depending on the combination of ligands. CONCLUSIONS/SIGNIFICANCE: Our screen substantially expands the set of PtdInsPs interacting PDZ domains, and shows that a full understanding of the biology of PDZ proteins will require a comprehensive insight into the intricate relationships between PDZ domains and their peptide and lipid ligands.

Autoradiographic analysis of tritiated imipramine binding in the human brain post mortem: effects of suicide

International Nuclear Information System (INIS)

Gross-Isseroff, R.; Israeli, M.; Biegon, A.

1989-01-01

In vitro quantitative autoradiography of high-affinity tritiated imipramine binding sites was performed on brains of 12 suicide victims and 12 matched controls. Region-specific differences in imipramine binding were found between the two groups. Thus, the pyramidal and molecular layers of the cornu ammoni hippocampal fields and the hilus of the dentate gyrus exhibited 80%, 60%, and 90% increases in binding in the suicide group, respectively. The postcentral cortical gyrus, insular cortex, and claustrum had 45%, 28%, and 75% decreases in binding in the suicide group, respectively. No difference in imipramine binding was observed in prefrontal cortical regions, in the basal ganglia, and in mesencephalic nuclei. No sex and postmortem delay effects on imipramine binding were found. Imipramine binding was positively correlated with age, the effect of age being most pronounced in portions of the basal ganglia and temporal cortex

[Molecular organization of glutamate-sensitive chemoexcitatory membranes of nerve cells. Comparative analysis of glutamate-binding membrane proteins from the cerebral cortex of rats and humans].

Science.gov (United States)

Dambinova, S A; Gorodinskiĭ, A I; Lekomtseva, T M; Koreshonkov, O N

1987-10-01

The kinetics of 3H-L-glutamate binding to human brain synaptic membranes revealed the existence of one type of binding sites with Kd and Vmax comparable with those for freshly isolated rat brain membranes. The fraction of glutamate-binding proteins (GBP) was shown to contain three components with Mr of 14, 60 and 280 kD whose stoichiometry is specific for human and rat brain. All fractions were found to bind the radiolabeled neurotransmitter and to dissociate into subunits with Mr of 14 kD after treatment with-potent detergents (with the exception of the 56-60 kD component). Study of association-dissociation of GBP protein subunits by high performance liquid chromatography confirmed the hypothesis on the oligomeric structure of glutamate receptors which are made up of low molecular weight glycoprotein-lipid subunits and which form ionic channels by way of repeated association. Despite the similarity of antigen determinants in the active center of glutamate receptors from human and rat brain, it was assumed that the stoichiometry of structural organization of receptor subunits isolated from different sources is different. The functional role of structural complexity of human brain glutamate receptors is discussed.

Cholecystokinin-8 suppressed /sup 3/H-etorphine binding to rat brain opiate receptors

Energy Technology Data Exchange (ETDEWEB)

Wang, X.J.; Fan, S.G.; Ren, M.F.; Han, J.S.

1989-01-01

Radioreceptor assay (RRA) was adopted to analyze the influence of CCK-8 on /sup 3/H-etorphine binding to opiate receptors in rat brain synaptosomal membranes (P2). In the competition experiment CCK-8 suppressed the binding of /sup 3/H-etorphine. This effect was completely reversed by proglumide at 1/mu/M. Rosenthal analysis for saturation revealed two populations of /sup 3/H-etorphine binding sites. CCK-8 inhibited /sup 3/H-etorphine binding to the high affinity sites by an increase in Kd and decrease in Bmax without significant changes in the Kd and Bmax of the low affinity sites. This effect of CCK-8 was also completely reversed by proglumide at 1/mu/M. Unsulfated CCK-8 produced only a slight increase in Kd of the high affinity sites without affecting Bmax. The results suggest that CCK-8 might be capable of suppressing the high affinity opioid binding sites via the activation of CCK receptor.

Heterogeneous binding of sigma radioligands in the rat brain and liver; Possible relationship to subforms of cytochrome P-450

Energy Technology Data Exchange (ETDEWEB)

Ross, S B [Research Laboratories, Astra Research Centre AB, Soedertaejle (Sweden)

1991-01-01

The binding of four sigma receptor ligands, {sup 3}H-(+)-N-allyl-N-normetazocine ({sup 3}H-(+)-SKF 10,047), {sup 3}H-(+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine ({sup 3}H-(+)-3-PPP), {sup 3}H-haloperidol and {sup 3}H-N,N'-di(o-totyl)guanidine ({sup 3}H-DTG), and the cytochrome P450IID6 ligand and dopamine uptake inhibitor {sup 3}H-1-(2-(diphenylmethoxy)ethyl)-4-(3-phenylpropyl)piperazine ({sup 3}H-GBR 12935) to membranal preparations of rat liver or whole rat brain was examined regarding kinetical properties and inhibition by various compounds with affinity for sigma binding sites or cytochrome P-450. In rat brain the density of binding sites was increased in order (+)-SKF 10,047<(+)-3-PPPbrain and liver. With the exception of {sup 3}H-(+)-SKF 10,047 there were quite marked differences between the ligands studied. Multiple binding sites were also indicated by the low Hill coefficients found for most of the compounds studied. It was found that the cytochrome P-450 inhibitor proadifen (SKF 525A), like haloperidol, was a potent inhibitor of the binding of {sup 3}H-(+)-SKF 10,047, {sup 3}H-(+)-3-PPP and {sup 3}H-haloperidol to the liver and brain preparations, less active in inhibiting the binding of {sup 3}H-DTG and least effective on the binding of {sup 3}H-GBR 12935. Another cytochrome P-450 inhibitor, L-lobeline, was particularly potent in inhibiting the binding of {sup 3}H-DTG but was also quite potent inhibitor of the binding of the other sigma ligands. It was less potent in inhibiting the binding of {sup 3}H-GBR 12935. The binding of the latter ligand was potently inhibited by the analogous compound GBR 12909 but of the other compounds examined only L-lobeline, proadifen, haloperidol, DTG and (+)-3-PPP had IC50 values below 10 {mu}M. (Abstract Truncated)

Characterization of kappa opioid binding using dynorphin A1-13 and U69,593 in the rat brain

Energy Technology Data Exchange (ETDEWEB)

Devlin, T.; Shoemaker, W.J. (Univ. of Connecticut Health Center, Farmington (USA))

1990-05-01

Previous studies of kappa opioid binding sites have suggested heterogeneous binding to this class of opioid receptors. To further investigate kappa receptor heterogeneity, we analyzed the binding properties of various kappa-selective ligands in rat brain homogenates. Displacement assays were carried out using (3H)bremazocine in the presence of various displacing ligands under mu and delta receptor-blocked conditions. Homologous displacement of (3H)bremazocine produced shallow displacement which best fit a two-site model of drug-receptor interaction. Dynorphin A1-13 and U69,593 exhibited similar biphasic displacement of (3H)bremazocine. Maximal displacement by these ligands, however, represented only approximately 55% of total (3H)bremazocine binding, which suggests the existence of a third component of (3H)bremazocine binding. Biphasic displacement by dynorphin A1-13 was detected in tissue throughout the brain and the spinal cord, whereas the dynorphin-resistant component of (3H)bremazocine binding was uniquely absent in the spinal cord. U50,488H, tifluadom and ethylketocyclazocine appeared to displace from additional, dynorphin-insensitive sites, as their maximal displacement exceeded that seen with either dynorphin A1-13 or U69,593. These results strongly suggest the existence of at least three components of non-mu, non-delta (3H)bremazocine binding in the rat brain: two with differential affinity for dynorphin A1-13 and U69-593 (kappa-1 and kappa-2 sites), and a third (termed here R1) that was further resolved into two binding sites by bremazocine. Preliminary analysis of the R1 component using naloxone revealed one high-affinity site, which may be opiate in nature, and a second site whose binding properties closely resemble those of the sigma receptor described by others.

Enhanced insulin binding to blood-brain barrier in vivo and to brain microvessels in vitro in newborn rabbits

International Nuclear Information System (INIS)

Frank, H.J.; Jankovic-Vokes, T.; Pardridge, W.M.; Morris, W.L.

1985-01-01

Insulin is a known growth factor in nonneural tissue, and recent studies have shown that there are insulin receptors throughout the adult and fetal central nervous system. Since insulin has only limited access to the adult brain, this study was undertaken to determine if insulin has increased availability to the newborn brain where it may act as a neonatal brain growth promoter. In vivo brain uptake of 125 I-insulin after a single-pass carotid injection was measured in newborn, 3-wk-old and 11-wk-old (adult) rabbits. The brain uptake index (BUI) relative to a 3 HOH reference was 22.0 +/- 1.1% (mean +/- SEM) for newborn, 12.8 +/- 0.6% for 3-wk-old, and 6.5 +/- 0.1% for adults. Specific 125 I-insulin binding to isolated cerebral microvessels was similarly increased in the newborn compared with the 3-wk-old and adult animals. Scatchard analysis revealed that the difference was due to an increase in receptor number with only minimal changes in the affinity. The increased availability of circulating insulin to the newborn brain was further corroborated by elevated CSF/serum and brain/serum insulin ratios in the newborn versus adult. These results suggest that insulin has increased access to the newborn brain where it may function as a growth factor

Evaluation of the binding of the radiolabeled antidepressant drug, {sup 18}F-fluoxetine in the rodent brain: an in vitro and in vivo study

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Mukherjee, Jogeshwar E-mail: jogeshwar_mukherjee@ketthealth.com; Das, Malay K.; Yang Zhiying; Lew, Robert

1998-10-01

We have developed {sup 18}F-fluoxetine as a radiotracer analog of the antidepressant drug fluoxetine (Prozac). In vitro saturation experiments of {sup 18}F-fluoxetine were carried out on rat midbrain tissue and citalopram was used for measuring nonspecific binding. A saturation curve for the binding of {sup 18}F-fluoxetine was not obtained. Even when fluoxetine (10 {mu}M) was used for measurements of nonspecific binding, a saturation curve was difficult to obtain. Other compounds, such as deprenyl, clorgyline, amphetamine, and reserpine were also not able to reduce the binding of {sup 18}F-fluoxetine. Ex vivo autoradiographic experiments with {sup 18}F-fluoxetine did not reveal any specific uptake in various brain regions. In vivo administration of {sup 18}F-fluoxetine in rats showed similar uptake in all the brain regions with little regional selectivity. A subcellular analysis of rat brain tissue after intravenous (IV) administration of {sup 18}F-fluoxetine indicated significant amounts of binding in mitochondria and synaptosomes. In summary, in vitro experiments with {sup 18}F-fluoxetine indicate little specific binding. Binding to the serotonin transporter was not identifiable. High nonspecific binding of the tracer resulting from its subcellular nature in the brain masks the ability to detect binding to the serotonin uptake sites in vivo. These findings indicate that a large portion of the binding of {sup 18}F-fluoxetine in rat brains is subcellular and clears slowly out of the cells. Other sites, such as monoamine oxidase, may also play a significant role in the action of fluoxetine.

Lipidomics of human brain aging and Alzheimer's disease pathology.

Science.gov (United States)

Naudí, Alba; Cabré, Rosanna; Jové, Mariona; Ayala, Victoria; Gonzalo, Hugo; Portero-Otín, Manuel; Ferrer, Isidre; Pamplona, Reinald

2015-01-01

Lipids stimulated and favored the evolution of the brain. Adult human brain contains a large amount of lipids, and the largest diversity of lipid classes and lipid molecular species. Lipidomics is defined as "the full characterization of lipid molecular species and of their biological roles with respect to expression of proteins involved in lipid metabolism and function, including gene regulation." Therefore, the study of brain lipidomics can help to unravel the diversity and to disclose the specificity of these lipid traits and its alterations in neural (neurons and glial) cells, groups of neural cells, brain, and fluids such as cerebrospinal fluid and plasma, thus helping to uncover potential biomarkers of human brain aging and Alzheimer disease. This review will discuss the lipid composition of the adult human brain. We first consider a brief approach to lipid definition, classification, and tools for analysis from the new point of view that has emerged with lipidomics, and then turn to the lipid profiles in human brain and how lipids affect brain function. Finally, we focus on the current status of lipidomics findings in human brain aging and Alzheimer's disease pathology. Neurolipidomics will increase knowledge about physiological and pathological functions of brain cells and will place the concept of selective neuronal vulnerability in a lipid context. © 2015 Elsevier Inc. All rights reserved.

Evidence that a synthetic amyloid-ß oligomer-binding peptide (ABP) targets amyloid-ß deposits in transgenic mouse brain and human Alzheimer's disease brain.

Science.gov (United States)

Chakravarthy, Balu; Ito, Shingo; Atkinson, Trevor; Gaudet, Chantal; Ménard, Michel; Brown, Leslie; Whitfield, James

2014-03-14

The synthetic ~5 kDa ABP (amyloid-ß binding peptide) consists of a region of the 228 kDa human pericentrioloar material-1 (PCM-1) protein that selectively and avidly binds in vitro Aβ1-42 oligomers, believed to be key co-drivers of Alzheimer's disease (AD), but not monomers (Chakravarthy et al., (2013) [3]). ABP also prevents Aß1-42 from triggering the apoptotic death of cultured human SHSY5Y neuroblasts, likely by sequestering Aß oligomers, suggesting that it might be a potential AD therapeutic. Here we support this possibility by showing that ABP also recognizes and binds Aβ1-42 aggregates in sections of cortices and hippocampi from brains of AD transgenic mice and human AD patients. More importantly, ABP targets Aβ1-42 aggregates when microinjected into the hippocampi of the brains of live AD transgenic mice. Crown Copyright © 2014. Published by Elsevier Inc. All rights reserved.

Alcohol-Binding Sites in Distinct Brain Proteins: The Quest for Atomic Level Resolution

Science.gov (United States)

Howard, Rebecca J.; Slesinger, Paul A.; Davies, Daryl L.; Das, Joydip; Trudell, James R.; Harris, R. Adron

2011-01-01

Defining the sites of action of ethanol on brain proteins is a major prerequisite to understanding the molecular pharmacology of this drug. The main barrier to reaching an atomic-level understanding of alcohol action is the low potency of alcohols, ethanol in particular, which is a reflection of transient, low-affinity interactions with their targets. These mechanisms are difficult or impossible to study with traditional techniques such as radioligand binding or spectroscopy. However, there has been considerable recent progress in combining X-ray crystallography, structural modeling, and site-directed mutagenesis to define the sites and mechanisms of action of ethanol and related alcohols on key brain proteins. We review such insights for several diverse classes of proteins including inwardly rectifying potassium, transient receptor potential, and neurotransmit-ter-gated ion channels, as well as protein kinase C epsilon. Some common themes are beginning to emerge from these proteins, including hydrogen bonding of the hydroxyl group and van der Waals interactions of the methylene groups of ethanol with specific amino acid residues. The resulting binding energy is proposed to facilitate or stabilize low-energy state transitions in the bound proteins, allowing ethanol to act as a “molecular lubricant” for protein function. We discuss evidence for characteristic, discrete alcohol-binding sites on protein targets, as well as evidence that binding to some proteins is better characterized by an interaction region that can accommodate multiple molecules of ethanol. PMID:21676006

Water extractable phytochemicals from Capsicum pubescens (tree pepper) inhibit lipid peroxidation induced by different pro-oxidant agents in brain

Energy Technology Data Exchange (ETDEWEB)

Oboh, G [Biochemistry Department, Federal University of Technology, Akure, Ondo State (Nigeria); [Departamento de Quimica, Universidade Federal de Santa Maria (UFSM), Campus Universitario - Camobi, Santa Maria RS (Brazil); [Abdus Salam International Centre for Theoretical Physics, Trieste (Italy)]. E-mail: goboh2001@yahoo.com; Rocha, J B.T. [Campus Universitario - Camobi, Santa Maria RS (Brazil)

2006-03-15

Reactive oxygen species (ROS) is the cause of neurodegenerative disorders such as Lou Gehrig's disease, Parkinson's disease and Huntington's disease; one practical way to prevent and manage neurodegenerative diseases is through the eating of food rich in antioxidants (dietary means). In this study, the antioxidant and neuroprotective properties of aqueous extract of ripe and unripe Capsicum pubescens (popularly known as tree pepper) on different pro-oxidant induced lipid peroxidation in Rat's brain (in vitro) is been investigated. Aqueous extract of freshly harvested pepper was prepared, and the total phenol content, vitamin C, ferric reducing antioxidant property (FRAP) and Fe (II) chelating ability was determined. In addition, the ability of the extracts to protect the Rat's brain against some pro-oxidant FeSO{sub 4}, Sodium nitroprusside and Quinolinic acid - induced oxidative stress was also determined. The results of the study revealed that ripe Capsicum pubescens had a significantly higher (P<0.05) total phenol [ripe (113.7mg/100g), unripe (70.5mg/100g)] content and ferric reducing antioxidant property than the unripe pepper. However, there was no significant difference in the vitamin C [ripe (231.5{mu}g/g), unripe (224.4{mu}g/g)] content and Fe (II) chelating ability. Furthermore, the pepper extracts caused a significant decrease (P<0.05) in 25{mu}M Fe(II), 7{mu}M Sodium Nitroprusside and 1mM Quinolinic acid induced lipid peroxidation in the Rat's brain in a dose-dependent manner. However, the ripe pepper inhibited MDA (Malondialdehyhide) production in the Rat's brain than the unripe pepper. Conversely, both extract did not significantly inhibit Fe (II)/H{sub 2}O{sub 2} induced decomposition of deoxyribose. Therefore, ripe and unripe Capsicum pubescens would inhibit lipid peroxidation in vitro. However, the ripe potent was a more potent inhibitor of lipid peroxidation, which is probably due to its higher vitamin C and phenol content, reducing power and Fe

Probing the interaction of brain fatty acid binding protein (B-FABP with model membranes.

Directory of Open Access Journals (Sweden)

Fábio Dyszy

Full Text Available Brain fatty acid-binding protein (B-FABP interacts with biological membranes and delivers polyunsaturated fatty acids (FAs via a collisional mechanism. The binding of FAs in the protein and the interaction with membranes involve a motif called "portal region", formed by two small α-helices, A1 and A2, connected by a loop. We used a combination of site-directed mutagenesis and electron spin resonance to probe the changes in the protein and in the membrane model induced by their interaction. Spin labeled B-FABP mutants and lipidic spin probes incorporated into a membrane model confirmed that B-FABP interacts with micelles through the portal region and led to structural changes in the protein as well in the micelles. These changes were greater in the presence of LPG when compared to the LPC models. ESR spectra of B-FABP labeled mutants showed the presence of two groups of residues that responded to the presence of micelles in opposite ways. In the presence of lysophospholipids, group I of residues, whose side chains point outwards from the contact region between the helices, had their mobility decreased in an environment of lower polarity when compared to the same residues in solution. The second group, composed by residues with side chains situated at the interface between the α-helices, experienced an increase in mobility in the presence of the model membranes. These modifications in the ESR spectra of B-FABP mutants are compatible with a less ordered structure of the portal region inner residues (group II that is likely to facilitate the delivery of FAs to target membranes. On the other hand, residues in group I and micelle components have their mobilities decreased probably as a result of the formation of a collisional complex. Our results bring new insights for the understanding of the gating and delivery mechanisms of FABPs.

The effect of ethanol on 35-S-TBPS binding to mouse brain membranes in the presence of chloride

International Nuclear Information System (INIS)

Liljequist, S.; Culp, S.; Tabakoff, B.

1989-01-01

The effect of in vitro and in vivo administration of ethanol on the binding of 35 S-t-butyl-bicyclophosphorothionate ( 35 S-TBPS) to cortical brain membranes of C57B1 mice was investigated using KCl (100 mM) containing assay media. The in vitro addition of ethanol produced a dose-dependent inhibition of basal 35 S-TBPS binding. In the presence of chloride ions, GABA and pentobarbital had a biphasic action (stimulation followed by inhibition) on 35 S-TBPS binding, whereas diazepam only stimulated the binding. Ethanol reduced the stimulatory effects of GABA and pentobarbital in a dose-dependent manner, but had no effect on the enhancement of 35 S-TBPS binding produced by diazepam. 35 S-TBPS binding to cortical brain membranes was inhibited by the putative Cl - channel blocking agent DIDS. This inhibitory action of DIDS was significantly, and dose-dependently reduced by ethanol (≤ 100 mM ethanol). Chronic ethanol ingestion in vivo, which produced tolerance to and physical dependence on ethanol in the animals, did not alter the stimulatory and inhibitory effects of GABA and pentobarbital on 35 S-TBPS binding. The enhancement of 35 S-TBPS binding produced by diazepam was slightly, but significantly, enhanced in brain membranes from animals which had undergone 24 hours of ethanol withdrawal. Chronic ethanol treatment did not change the potency of picrotoxin and of the peripheral BDZ-receptor ligand RO 5-4864 to competitively inhibit 35 S-TBPS binding. Our results suggest that in vitro addition of ethanol alters the activity of the activity of the GABA benzodiazepine (BDZ) receptor complex. Although there was no change in basal 35 S-TBPS binding following chronic in vivo ethanol administration, our curent data suggest that chronic ethanol ingestion may cause specific changes of the GABA BDZ receptor proteins, in this study revealed as an altered modulation of 35 S-TBPS binding by diazepam. (author)

The simulation approach to lipid-protein interactions.

Science.gov (United States)

Paramo, Teresa; Garzón, Diana; Holdbrook, Daniel A; Khalid, Syma; Bond, Peter J

2013-01-01

The interactions between lipids and proteins are crucial for a range of biological processes, from the folding and stability of membrane proteins to signaling and metabolism facilitated by lipid-binding proteins. However, high-resolution structural details concerning functional lipid/protein interactions are scarce due to barriers in both experimental isolation of native lipid-bound complexes and subsequent biophysical characterization. The molecular dynamics (MD) simulation approach provides a means to complement available structural data, yielding dynamic, structural, and thermodynamic data for a protein embedded within a physiologically realistic, modelled lipid environment. In this chapter, we provide a guide to current methods for setting up and running simulations of membrane proteins and soluble, lipid-binding proteins, using standard atomistically detailed representations, as well as simplified, coarse-grained models. In addition, we outline recent studies that illustrate the power of the simulation approach in the context of biologically relevant lipid/protein interactions.

The role of the kidney in lipid metabolism

DEFF Research Database (Denmark)

Moestrup, Søren K; Nielsen, Lars Bo

2005-01-01

PURPOSE OF REVIEW: Cellular uptake of plasma lipids is to a large extent mediated by specific membrane-associated proteins that recognize lipid-protein complexes. In the kidney, the apical surface of proximal tubules has a high capacity for receptor-mediated uptake of filtered lipid-binding plasma...... proteins. We describe the renal receptor system and its role in lipid metabolism in health and disease, and discuss the general effect of the diseased kidney on lipid metabolism. RECENT FINDINGS: Megalin and cubilin are receptors in the proximal tubules. An accumulating number of lipid......-binding and regulating proteins (e.g. albumin, apolipoprotein A-I and leptin) have been identified as ligands, suggesting that their receptors may directly take up lipids in the proximal tubules and indirectly affect plasma and tissue lipid metabolism. Recently, the amnionless protein was shown to be essential...

Nicotinic binding in rat brain: autoradiographic comparison of [3H]acetylcholine, [3H]nicotine, and [125I]-alpha-bungarotoxin

International Nuclear Information System (INIS)

Clarke, P.B.; Schwartz, R.D.; Paul, S.M.; Pert, C.B.; Pert, A.

1985-01-01

Three radioligands have been commonly used to label putative nicotinic cholinoceptors in the mammalian central nervous system: the agonists [ 3 H]nicotine and [ 3 H]acetylcholine ([ 3 H]ACh--in the presence of atropine to block muscarinic receptors), and the snake venom extract, [ 125 I]-alpha-bungarotoxin([ 125 I]BTX), which acts as a nicotinic antagonist at the neuromuscular junction. Binding studies employing brain homogenates indicate that the regional distributions of both [ 3 H]nicotine and [ 3 H]ACh differ from that of [ 125 I]BTX. The possible relationship between brain sites bound by [ 3 H]nicotine and [ 3 H]ACh has not been examined directly. The authors have used the technique of autoradiography to produce detailed maps of [ 3 H]nicotine, [ 3 H]ACh, and [ 125 I]BTX labeling; near-adjacent tissue sections were compared at many levels of the rat brain. The maps of high affinity agonist labeling are strikingly concordant, with highest densities in the interpeduncular nucleus, most thalamic nuclei, superior colliculus, medial habenula, presubiculum, cerebral cortex (layers I and III/IV), and the substantia nigra pars compacta/ventral tegmental area. The pattern of [ 125 I]BTX binding is strikingly different, the only notable overlap with agonist binding being the cerebral cortex (layer I) and superior colliculus. [ 125 I]BTX binding is also dense in the inferior colliculus, cerebral cortex (layer VI), hypothalamus, and hippocampus, but is virtually absent in thalamus. Various lines of evidence suggest that the high affinity agonist-binding sites in brain correspond to nicotinic cholinergic receptors similar to those found at autonomic ganglia; BTX-binding sites may also serve as receptors for nicotine and are possibly related to neuromuscular nicotinic cholinoceptors

Brain delivery of camptothecin by means of solid lipid nanoparticles: Formulation design, in vitro and in vivo studies

DEFF Research Database (Denmark)

Martins, S.; Tho, I.; Reimold, I.

2012-01-01

that fluorescently labelled SLN were detected in the brain after i.v. administration. This study indicates that the camptothecin-loaded SLN are a promising drug brain delivery system worth to explore further for brain tumour therapy. (C) 2012 Elsevier B. V. All rights reserved.......For the purpose of brain delivery upon intravenous injection, formulations of camptothecin-loaded solid lipid nanoparticles (SLN), prepared by hot high pressure homogenisation, were designed. Incorporation of camptothecin in the hydrophobic and acidic environment of SLN matrix was chosen...... to stabilise the lactone ring, which is essential for its antitumour activity, and for avoiding premature loss of drug on the way to target camptothecin to the brain. A multivariate approach was used to assess the influence of the qualitative and quantitative composition on the physicochemical properties...

[3H]muscimol binding sites increased in autopsied brains of chronic schizophrenics

International Nuclear Information System (INIS)

Hanada, S.; Mita, T.; Nishino, N.; Tanaka, C.

1987-01-01

[ 3 H]muscimol binding and glutamic acid decarboxylase (GAD) activity in the prefrontal cortex and caudate nucleus of autopsied brains from 19 chronic schizophrenics and 17 control subjects were investigated. In the schizophrenics, saturation analysis with varying concentrations of [ 3 H]muscimol revealed an increase in the number GABA/sub A/ receptors, but there was no significant difference in the affinity. In addition, the enhancement of [ 3 H]muscimol binding by diazepam was significantly greater in schizophrenics than in controls. GAD activity did not differ between controls and schizophrenics. The possibility that GABAergic mechanisms might play a role in case of chronic schizophrenia should be given further attention

Astrocyte lipid metabolism is critical for synapse development and function in vivo.

Science.gov (United States)

van Deijk, Anne-Lieke F; Camargo, Nutabi; Timmerman, Jaap; Heistek, Tim; Brouwers, Jos F; Mogavero, Floriana; Mansvelder, Huibert D; Smit, August B; Verheijen, Mark H G

2017-04-01

The brain is considered to be autonomous in lipid synthesis with astrocytes producing lipids far more efficiently than neurons. Accordingly, it is generally assumed that astrocyte-derived lipids are taken up by neurons to support synapse formation and function. Initial confirmation of this assumption has been obtained in cell cultures, but whether astrocyte-derived lipids support synapses in vivo is not known. Here, we address this issue and determined the role of astrocyte lipid metabolism in hippocampal synapse formation and function in vivo. Hippocampal protein expression for the sterol regulatory element-binding protein (SREBP) and its target gene fatty acid synthase (Fasn) was found in astrocytes but not in neurons. Diminishing SREBP activity in astrocytes using mice in which the SREBP cleavage-activating protein (SCAP) was deleted from GFAP-expressing cells resulted in decreased cholesterol and phospholipid secretion by astrocytes. Interestingly, SCAP mutant mice showed more immature synapses, lower presynaptic protein SNAP-25 levels as well as reduced numbers of synaptic vesicles, indicating impaired development of the presynaptic terminal. Accordingly, hippocampal short-term and long-term synaptic plasticity were defective in mutant mice. These findings establish a critical role for astrocyte lipid metabolism in presynaptic terminal development and function in vivo. GLIA 2017;65:670-682. © 2017 Wiley Periodicals, Inc.

Opiate antagonist binding sites in discrete brain regions of spontaneously hypertensive and normotensive Wistar-Kyoto rats

Energy Technology Data Exchange (ETDEWEB)

Rahmani, N.H.; Gulati, A.; Bhargava, H.N. (Univ. of Illinois, Chicago (USA))

1991-01-01

The binding of {sup 3}H-naltrexone, an opiate receptor antagonist, to membranes of discrete brain regions and spinal cord of 10 week old spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto (WKY) rats was determined. The brain regions examined were hypothalamus, amygdala, hippocampus, corpus striatum, pons and medulla, midbrain and cortex. {sup 3}H-Naltrexone bound to membranes of brain regions and spinal cord at a single high affinity site with an apparent dissociation constant value of 3 nM. The highest density of {sup 3}H-naltrexone binding sites were in hippocampus and lowest in the cerebral cortex. The receptor density (B{sub max}value) and apparent dissociation constant (K{sub d} value) values of {sup 3}H-naltrexone to bind to opiate receptors on the membranes of amygdala, hippocampus, corpus striatum, pons and medulla, midgrain, cortex and spinal cord of WKY and SHR rates did not differ. The B{sub max} value of {sup 3}H-naltrexone binding to membranes of hypothalamus of SHR rates was 518% higher than WKY rats but the K{sub d} values in the two strains did not differ. It is concluded that SHR rats have higher density of opiate receptors labeled with {sup 3}H-naltrexone in the hypothalamus only, in comparison with WKY rats, and that such a difference in the density of opiate receptors may be related to the elevated blood pressure in SHR rats.

Metabolic Profiles of Brain Metastases

Directory of Open Access Journals (Sweden)

Tone F. Bathen

2013-01-01

Full Text Available Metastasis to the brain is a feared complication of systemic cancer, associated with significant morbidity and poor prognosis. A better understanding of the tumor metabolism might help us meet the challenges in controlling brain metastases. The study aims to characterize the metabolic profile of brain metastases of different origin using high resolution magic angle spinning (HR-MAS magnetic resonance spectroscopy (MRS to correlate the metabolic profiles to clinical and pathological information. Biopsy samples of human brain metastases (n = 49 were investigated. A significant correlation between lipid signals and necrosis in brain metastases was observed (p < 0.01, irrespective of their primary origin. The principal component analysis (PCA showed that brain metastases from malignant melanomas cluster together, while lung carcinomas were metabolically heterogeneous and overlap with other subtypes. Metastatic melanomas have higher amounts of glycerophosphocholine than other brain metastases. A significant correlation between microscopically visible lipid droplets estimated by Nile Red staining and MR visible lipid signals was observed in metastatic lung carcinomas (p = 0.01, indicating that the proton MR visible lipid signals arise from cytoplasmic lipid droplets. MRS-based metabolomic profiling is a useful tool for exploring the metabolic profiles of metastatic brain tumors.

Ionizing radiation alters the properties of sodium channels in rat brain synaptosomes

Energy Technology Data Exchange (ETDEWEB)

Mullin, M J; Hunt, W A; Harris, R A

1986-08-01

The effect of ionizing radiation on neuronal membrane function was assessed by measurement of neurotoxin-stimulated /sup 22/Na/sup +/ uptake by rat brain synaptosomes. High-energy electrons and gamma photons were equally effective in reducing the maximal uptake of /sup 22/Na/sup +/ with no significant change in the affinity of veratridine for its binding site in the channel. Ionizing radiation reduced the veratridine-stimulated uptake at the earliest times measured (3 and 5 s), when the rate of uptake was greatest. Batrachotoxin-stimulated /sup 22/Na/sup +/ uptake was less sensitive to inhibition by radiation. The binding of (/sup 3/H)saxitoxin to its receptor in the sodium channel was unaffected by exposure to ionizing radiation. The effect of ionizing radiation on the lipid order of rat brain synaptic plasma membranes was measured by the fluorescence polarization of the molecular probes 1,6-diphenyl-1,3,5-hexatriene and 1-(4-(trimethylammonium)phenyl)-6-phenyl-1,3,5-hexatriene. A dose of radiation that reduced the veratridine-stimulated uptake of /sup 22/Na/sup +/ had no effect on the fluorescence polarization of either probe. These results demonstrate an inhibitory effect of ionizing radiation on the voltage-sensitive sodium channels in rat brain synaptosomes. This effect of radiation is not dependent on changes in the order of membrane lipids.

Lipid microbubbles as a vehicle for targeted drug delivery using focused ultrasound-induced blood-brain barrier opening.

Science.gov (United States)

Sierra, Carlos; Acosta, Camilo; Chen, Cherry; Wu, Shih-Ying; Karakatsani, Maria E; Bernal, Manuel; Konofagou, Elisa E

2017-04-01

Focused ultrasound in conjunction with lipid microbubbles has fully demonstrated its ability to induce non-invasive, transient, and reversible blood-brain barrier opening. This study was aimed at testing the feasibility of our lipid-coated microbubbles as a vector for targeted drug delivery in the treatment of central nervous system diseases. These microbubbles were labeled with the fluorophore 5-dodecanoylaminfluorescein. Focused ultrasound targeted mouse brains in vivo in the presence of these microbubbles for trans-blood-brain barrier delivery of 5-dodecanoylaminfluorescein. This new approach, compared to previously studies of our group, where fluorescently labeled dextrans and microbubbles were co-administered, represents an appreciable improvement in safety outcome and targeted drug delivery. This novel technique allows the delivery of 5-dodecanoylaminfluorescein at the region of interest unlike the alternative of systemic exposure. 5-dodecanoylaminfluorescein delivery was assessed by ex vivo fluorescence imaging and by in vivo transcranial passive cavitation detection. Stable and inertial cavitation doses were quantified. The cavitation dose thresholds for estimating, a priori, successful targeted drug delivery were, for the first time, identified with inertial cavitation were concluded to be necessary for successful delivery. The findings presented herein indicate the feasibility and safety of the proposed microbubble-based targeted drug delivery and that, if successful, can be predicted by cavitation detection in vivo.

Schistosoma mansoni venom allergen-like protein 4 (SmVAL4) is a novel lipid-binding SCP/TAPS protein that lacks the prototypical CAP motifs

Energy Technology Data Exchange (ETDEWEB)

Kelleher, Alan [Baylor College of Medicine, Houston, TX 77030 (United States); Darwiche, Rabih [University of Fribourg, Chemin du Musée 10, CH 1700 Fribourg (Switzerland); Rezende, Wanderson C. [Baylor College of Medicine, Houston, TX 77030 (United States); Farias, Leonardo P.; Leite, Luciana C. C. [Instituto Butantan, São Paulo, SP (Brazil); Schneiter, Roger [University of Fribourg, Chemin du Musée 10, CH 1700 Fribourg (Switzerland); Asojo, Oluwatoyin A., E-mail: asojo@bcm.edu [Baylor College of Medicine, Houston, TX 77030 (United States)

2014-08-01

The first structure of an S. mansoni venom allergen-like protein is presented. Schistosomiasis is a parasitic disease that affects over 200 million people. Vaccine candidates have been identified, including Schistosoma mansoni venom allergen-like proteins (SmVALs) from the SCP/TAPS (sperm-coating protein/Tpx/antigen 5/pathogenesis related-1/Sc7) superfamily. The first SmVAL structure, SmVAL4, was refined to a resolution limit of 2.16 Å. SmVAL4 has a unique structure that could not be predicted from homologous structures, with longer loops and an unusual C-terminal extension. SmVAL4 has the characteristic α/β-sandwich and central SCP/TAPS cavity. Furthermore, SmVAL4 has only one of the signature CAP cavity tetrad amino-acid residues and is missing the histidines that coordinate divalent cations such as Zn{sup 2+} in other SCP/TAPS proteins. SmVAL4 has a cavity between α-helices 1 and 4 that was observed to bind lipids in tablysin-15, suggesting the ability to bind lipids. Subsequently, SmVAL4 was shown to bind cholesterol in vitro. Additionally, SmVAL4 was shown to complement the in vivo sterol-export phenotype of yeast mutants lacking their endogenous CAP proteins. Expression of SmVAL4 in yeast cells lacking endogenous CAP function restores the block in sterol export. These studies suggest an evolutionarily conserved lipid-binding function shared by CAP proteins such as SmVAL4 and yeast CAP proteins such as Pry1.

Investigation and characterization of receptors for pituitary adenylate cyclase-activating polypeptide in human brain by radioligand binding and chemical cross-linking

International Nuclear Information System (INIS)

Suda, K.; Smith, D.M.; Ghatei, M.A.; Murphy, J.K.; Bloom, S.R.

1991-01-01

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a novel peptide of hypothalamic origin which increases adenylate cyclase activity in rat anterior pituitary cell cultures. The 38-amino acid peptide shows a close sequence homology to vasoactive intestinal peptide (VIP). Binding sites for PACAP in membranes from postmortem human brain tissue were studied using [ 125 I]PACAP27 as the radioligand. High specific binding sites (amount of specific binding measured at 0.25 nM [ 125 I]PACAP27 in femtomoles per mg protein +/- SEM; n = 4) were present in hypothalamus (344.5 +/- 13.0), brain stem (343.0 +/- 29.3), cerebellum (292.0 +/- 21.1), cortex (259.6 +/- 19.8), and basal ganglia (259.2 +/- 50.3). Specific binding sites in pituitary, although present, were less abundant (35.0 +/- 8.9). Binding of [ 125 I]PACAP27 was reversible and time, pH, and temperature dependent. Despite the homology with VIP, VIP was a poor inhibitor of [ 125 I]PACAP27 binding (IC50, greater than 1 microM) compared with PACAP27 (IC50, 0.5-1.3 nM) and PACAP38 (IC50, 0.2-1.3 nM). Scatchard plots of [ 125 I]PACAP27 binding showed the presence of both high and lower affinity sites. Chemical cross-linking of PACAP-binding sites revealed that [ 125 I]PACAP27 was bound to polypeptide chains of 67,000 and 48,000 mol wt. Thus, we have demonstrated the presence of PACAP-specific receptors in human brain which are not VIP receptors. This opens the possibility of PACAP functioning as a novel neurotransmitter/neuromodulator in human brain

Characterization and autoradiographic visualization of (+)-[3H]SKF10,047 binding in rat and mouse brain: further evidence for phencyclidine/sigma opiate receptor commonality

International Nuclear Information System (INIS)

Sircar, R.; Nichtenhauser, R.; Ieni, J.R.; Zukin, S.R.

1986-01-01

The binding specificity of (+)-[ 3 H]N-allylnormetazocine, the dextrorotatory isomer of the prototypical sigma opiate SKF10,047, was determined in rat and mouse brain and the neuroanatomical distribution of its binding sites elucidated by quantitative autoradiography in sections of rat brain. Computer-assisted Scatchard analysis revealed an apparent two-site fit of the binding data in both species and in all rat brain regions examined. In whole rat brain, the Kd values were 3.6 and 153 nM and the maximum binding values were 40 fmol and 1.6 pmol/mg of protein for the apparent high- and low-affinity binding sites, respectively. (+)-SKF10,047, haloperidol and pentazocine were among the most potent inhibitors of 7 nM (+)-[ 3 H]SKF10,047 binding to the higher affinity sites; rank orders of ligand potencies at these sites differ sharply from those that have been reported for the [ 3 H]phencyclidine (PCP) site, or for eliciting PCP-like or SKF10,047-like behaviors. By contrast, rank orders of potency of sigma opiods, PCP derivatives and dioxolanes for displacement of 100 nM (+)-[ 3 H]SKF10,047 from the more numerous lower affinity sites in the presence of 100 nM haloperidol agreed closely with their potencies in the [ 3 H]PCP binding assay as well as their potencies in exerting PCP- or SKF10,047-like behavioral effects. In order to compare directly the anatomical localizations of PCP and (+)-SKF10,047 binding sites, quantitative light microscopy autoradiography utilizing tritium-labeled PCP and (+)-SKF10,047 was carried out in rat brain sections. (+)-[ 3 H]SKF10,047 binding was observed to follow the regional pattern of [3H]PCP binding but also to bind in other regions not associated with PCP receptors

Lipid peroxidation in neonatal mouse brain subjected to two different types of hypoxia.

Science.gov (United States)

Hasegawa, K; Yoshioka, H; Sawada, T; Nishikawa, H

1991-01-01

To elucidate the role of free radicals in the pathogenesis of neonatal hypoxic encephalopathy, we determined the content of thiobarbituric acid reactants (TBARs), as an index of lipid peroxidation related with a free radical reaction, in the brains of newborn mice during hypoxia and recovery from hypoxia. Hypoxic stress was induced by 100% nitrogen gas breathing (N2 group) or 100% carbon dioxide gas breathing (CO2 group). TBARs increased with 20 minutes of hypoxia and returned to the control level during the recovery period in both groups. The increase in TBARs in the CO2 group was greater than that in the N2 group. These results may suggest that free radical reaction occurs during the hypoxic period and that CO2 hypoxia is more effective on free radical production in the newborn brain than N2 hypoxia.

Oxytocin receptor ligand binding in embryonic tissue and postnatal brain development of the C57BL/6J mouse

Directory of Open Access Journals (Sweden)

Elizabeth eHammock

2013-12-01

Full Text Available Oxytocin (OXT has drawn increasing attention as a developmentally relevant neuropeptide given its role in the brain regulation of social behavior. It has been suggested that OXT plays an important role in the infant brain during caregiver attachment in nurturing familial contexts, but there is incomplete experimental evidence. Mouse models of OXT system genes have been particularly informative for the role of the OXT system in social behavior, however, the developing brain areas that could respond to ligand activation of the OXT receptor (OXTR have yet to be identified in this species. Here we report new data revealing dynamic ligand-binding distribution of OXTR in the developing mouse brain. Using male and female C57BL/6J mice at postnatal days (P 0, 7, 14, 21, 35, and 60 we quantified OXTR ligand binding in several brain areas which changed across development. Further, we describe OXTR ligand binding in select tissues of the near-term whole embryo at E18.5. Together, these data aid in the interpretation of findings in mouse models of the OXT system and generate new testable hypotheses for developmental roles for OXT in mammalian systems. We discuss our findings in the context of developmental disorders (including autism, attachment biology, and infant physiological regulation.

Effects of anesthesia on [11C]raclopride binding in the rat brain

DEFF Research Database (Denmark)

Alstrup, Aage Kristian Olsen; Simonsen, Mette; Møller, Arne

Background Very often rats are anesthetized prior to micro positron emission tomography (microPET) brain imaging in order to prevent head movements. Anesthesia can be administered by inhalation agents, such as isoflurane, or injection mixtures, such as fentanyl-fluanisone-midazolam. Unfortunately......, anesthesia affects a variety of physiological variables, including in the brain. Aim The aim of this study was to compare the effects of inhalation and injection anesthesia on the binding potential of the dopaminergic D2/3 tracer [11C]raclopride used for PET brain imaging in human and animal studies....... Materials & Methods Nine male Lew/Mol rats were assigned to either inhalation (isoflurane; N=4) or injection (fentanyl-fluanisone-midazolam; N=5) anesthesia. Catheters were surgically placed in femoral arteries and veins for blood sampling and tracer injection. After a short attenuation scan, the rats were...

Autoradiographic imaging and quantification of the high-affinity GHB binding sites in rodent brain using (3)H-HOCPCA

DEFF Research Database (Denmark)

Klein, A B; Bay, T; Villumsen, I S

2016-01-01

analogue, 3-hydroxycyclopent-1-enecarboxylic acid (HOCPCA) as a tritiated version ((3)H-HOCPCA) to radioactively label the specific GHB high-affinity binding site and gain further insight into the density, distribution and developmental profile of this protein. We show that, in low nanomolar concentrations...... brain development. Due to the high sensitivity of this radioligand, we were able to detect low levels of specific binding already at E15 in mouse brain, which increased progressively until adulthood. Collectively, we show that (3)H-HOCPCA is a highly sensitive radioligand, offering advantages over...

Natural lipid extracts and biomembrane-mimicking lipid compositions are disposed to form nonlamellar phases, and they release DNA from lipoplexes most efficiently

Energy Technology Data Exchange (ETDEWEB)

Koynova, Rumiana; MacDonald, Robert C. (NWU)

2010-01-18

A viewpoint now emerging is that a critical factor in lipid-mediated transfection (lipofection) is the structural evolution of lipoplexes upon interacting and mixing with cellular lipids. Here we report our finding that lipid mixtures mimicking biomembrane lipid compositions are superior to pure anionic liposomes in their ability to release DNA from lipoplexes (cationic lipid/DNA complexes), even though they have a much lower negative charge density (and thus lower capacity to neutralize the positive charge of the lipoplex lipids). Flow fluorometry revealed that the portion of DNA released after a 30-min incubation of the cationic O-ethylphosphatidylcholine lipoplexes with the anionic phosphatidylserine or phosphatidylglycerol was 19% and 37%, respectively, whereas a mixture mimicking biomembranes (MM: phosphatidylcholine/phosphatidylethanolamine/phosphatidylserine /cholesterol 45:20:20:15 w/w) and polar lipid extract from bovine liver released 62% and 74%, respectively, of the DNA content. A possible reason for this superior power in releasing DNA by the natural lipid mixtures was suggested by structural experiments: while pure anionic lipids typically form lamellae, the natural lipid mixtures exhibited a surprising predilection to form nonlamellar phases. Thus, the MM mixture arranged into lamellar arrays at physiological temperature, but began to convert to the hexagonal phase at a slightly higher temperature, {approx} 40-45 C. A propensity to form nonlamellar phases (hexagonal, cubic, micellar) at close to physiological temperatures was also found with the lipid extracts from natural tissues (from bovine liver, brain, and heart). This result reveals that electrostatic interactions are only one of the factors involved in lipid-mediated DNA delivery. The tendency of lipid bilayers to form nonlamellar phases has been described in terms of bilayer 'frustration' which imposes a nonzero intrinsic curvature of the two opposing monolayers. Because the stored

Effects of dopaminergic drug treatments on in vivo radioligand binding to brain vesicular monoamine transporters

Energy Technology Data Exchange (ETDEWEB)

Kilbourn, Michael R; Frey, Kirk A; Vander Borght, Thierry; Sherman, Phillip S

1996-05-01

The effects of various dopaminergic drug treatments on the in vivo regional brain distribution of high-affinity radioligands ([{sup 11}C]dihydrotetrabenazine and [{sup 11}C]methoxytetrabenazine) for the rat brain vesicular monoamine transporter (VMAT2) were determined. Acute treatments with reserpine (2 mg/kg i.p.), tetrabenazine (10 mg/kg i.v.) or related benzoisoquinolines significantly reduced radiotracer binding in vivo. In contrast, radiotracer distributions remained unchanged after treatments with other dopaminergic drugs, whether given by single injection (haloperidol, 1 mg/kg i.p., pargyline 80 mg/kg), repeatedly (pargyline, 80 mg/kg s.c., 14 days), or by continuous infusion (deprenyl, 10 mg/kg/day, 5 days; L-DOPA methyl ester 100 mg/kg/day, 5 days). Repeated injections of tetrabenazine (5 mg/kg i.p., twice daily, 3 days) did not alter in vivo radioligand binding measured after allowing drug washout from the brain. These studies support the proposal that in vivo PET imaging of VMAT2 radioligands in patients with extrapyramidal movement disorders will not be affected by concurrent use of L-DOPA or deprenyl.

Autoradiographic analysis of the in vivo distribution of 3H-imipramine and 3H-desipramine in brain: Comparison to in vitro binding patterns

International Nuclear Information System (INIS)

Duncan, G.E.; Paul, I.A.; Fassberg, J.B.; Powell, K.R.; Stumpf, W.E.; Breese, G.R.

1991-01-01

Using high resolution autoradiographic techniques, the distribution of radioactivity in forebrain and brainstem was assessed after 4 injection of 3H-impramine or 3H-desipramine. Results were compared with regional binding of the drugs to brain sections in vitro. Similar topographic binding of 3H-imipramine and 3H-desipramine was observed in vitro among brain regions, except in the paraventricular nucleus of the hypothalamus and locus coeruleus, where binding was greater for 3H-desipramine. For both 3H-desipramine and 3H-imipramine, some brain regions that exhibited high binding in vitro also showed high accumulation after in vivo injection. However, certain regions that contained high densities of binding sites for the antidepressant drugs as measured by in vitro binding showed very low accumulation of radioactivity after in vivo treatment. Such regions included the dentate gyrus of the hippocampus, layer 1 of piriform cortex, caudate-putamen, pontine and midbrain central gray, and cerebellar granular layer. Compared to in vitro binding of the drugs, the distribution of imipramine and desipramine in vivo appears more anatomically selective. For imipramine, primary sites of action in vivo, as indicated by the topographic distribution in brain, appear to be the locus coeruleus, hippocampus, lateral septal nucleus, and amygdala. For desipramine, the greatest accumulation in vivo was found in the locus coeruleus, paraventricular nucleus of the hypothalamus, and anterior thalamic nuclei

The effect of ethanol on sup 35 -S-TBPS binding to mouse brain membranes in the presence of chloride

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Liljequist, S.; Culp, S.; Tabakoff, B. (Laboratory for Studies of Neuroadaptive Processes, National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda (USA))

1989-01-01

The effect of in vitro and in vivo administration of ethanol on the binding of {sup 35}S-t-butyl-bicyclophosphorothionate ({sup 35}S-TBPS) to cortical brain membranes of C57B1 mice was investigated using KCl containing assay media. The in vitro addition of ethanol produced a dose-dependent inhibition of basal {sup 35}S-TBPS binding. In the presence of chloride ions, GABA and pentobarbital had a biphasic action on {sup 35}S-TBPS binding, whereas diazepam only stimulated the binding. Ethanol reduced the stimulatory effects of GABA and pentobarbital in a dose-dependent manner, but had no effect on the enhancement of {sup 35}S-TBPS binding produced by diazepam. {sup 35}S-TBPS binding to cortical brain membranes was inhibited by the putative Cl{sup -} channel blocking agent DIDS. This inhibitory action of DIDS was significantly, and dose-dependently reduced by ethanol. Chronic ethanol ingestion in vivo, which produced tolerance to and physical dependence on ethanol in the animals, did not alter the stimulatory and inhibitory effects of GABA and pentobarbital on {sup 35}S-TBPS binding. The enhancement of {sup 35}S-TBPS binding produced by diazepam was slightly, but significantly, enhanced in brain membranes from animals which had undergone 24 hours of ethanol withdrawal. Chronic ethanol treatment did not change the potency of picrotoxin and of the peripheral BDZ-receptor ligand RO 5-4864 to competitively inhibit {sup 35}S-TBPS binding. Our results suggest that in vitro addition of ethanol alters the activity of the activity of the GABA benzodiazepine (BDZ) receptor complex. Although there was no change in basal {sup 35}S-TBPS binding following chronic in vivo ethanol administration, our curent data suggest that chronic ethanol ingestion may cause specific changes of the GABA BDZ receptor proteins, in this study revealed as an altered modulation of {sup 35}S-TBPS binding by diazepam.

Autoradiographic determination of catechol estrogen binding sites in brain, pituitary and uterus

International Nuclear Information System (INIS)

Parvizi, N.; Sar, M.; Duncan, G.E.; Stumpf, W.E.

1985-01-01

The anatomical pattern of nuclear binding of 2-OH[6,9- 3 H]estradiol ([ 3 H]2-OHE 2 ) in brain, pituitary and uterus have been studied autoradiographically. Autoradiograms of forebrain, pituitary and uterus show nuclear concentrations of radioactivity in certain cells. This nuclear concentration is abolished when unlabelled 2-OHE 2 or E 2 was injected prior to the injection of [ 3 H]2-OHE 2 . In the brain nuclear labelling is observed in the septal-preoptic region, in the anterior hypothalamic area, and in the central hypothalamic area. Some estrogen-sensitive nuclear groups, such as lateral septum and hippocampus, do not show accumulation of radioactivity. In the uterus, luminal and glandular epithelium, stromal cell and muscle cells are labelled. A comparison of the quantitative nuclear uptake of radioactivity and of the different time intervals after the injection of different doses shows similar uptake of nuclear radioactivity. This is comparable to data obtained after [6,7- 3 H]estradiol ([ 3 H]E 2 ) injection. The results provide clear evidence for nuclear binding of catechol estrogens of the same magnitude as [ 3 H]E 2 after in vivo treatment. (Auth.).0

In vivo binding of tritiated dopaminergic ligands in mouse brain

International Nuclear Information System (INIS)

Baudry, Michel; Martres, M.-P.; Le Sellin, Michel; Schwartz, J.-C.; Guyon, Anne; Morgat, J.-L.

1977-01-01

The regional distribution of various dopaminergic radiolabelled ligands has been studied in the mouse brain after their intravenous injections. Among them, 3 H-pimozide and, to a lesser extent, 3 H-apomorphine are preferentially accumulated in the striatum, a region rich in dopaminergic receptors, as compared to cerebellum, a region believed not to contain dopaminergic receptors. For 3 H-pimozide, this preferential retention is due to a more rapid disappearance from the cerebellum than from the striatum. Moreover, prior administration of various neuroleptics which do not modify 3 H-pimozide levels recovered in the cerebellum, abolishes the differential retention of 3 H-pimozide in the striatum. These results indicate that the retention of 3 H-pimozide in the brain may be regarded as the sum of two components: a non-specific retention evaluated by 3 H-pimozide level in the cerebellum and the binding to dopaminergic receptors [fr

The unusual lipid binding proteins of parasitic helminths and their potential roles in parasitism and as therapeutic targets.

Science.gov (United States)

Franchini, Gisela R; Pórfido, Jorge L; Ibáñez Shimabukuro, Marina; Rey Burusco, María F; Bélgamo, Julián A; Smith, Brian O; Kennedy, Malcolm W; Córsico, Betina

2015-02-01

In this review paper we aim at presenting the current knowledge on structural aspects of soluble lipid binding proteins (LBPs) found in parasitic helminths and to discuss their potential role as novel drug targets. Helminth parasites produce and secrete a great variety of LBPs that may participate in the acquisition of nutrients from their host, such as fatty acids and cholesterol. It is also postulated that LBPs might interfere in the regulation of the host׳s immune response by sequestering lipidic intermediates or delivering bioactive lipids. A detailed comprehension of the structure of these proteins, as well as their interactions with ligands and membranes, is important to understand host-parasite relationships that they may mediate. This information could also contribute to determining the role that these proteins may play in the biology of parasitic helminths and how they modulate the immune systems of their hosts, and also towards the development of new therapeutics and prevention of the diseases caused by these highly pathogenic parasites. Copyright © 2014 Elsevier Ltd. All rights reserved.

Repeated mild traumatic brain injury in female rats increases lipid peroxidation in neurons.

Science.gov (United States)

Yates, Nathanael J; Lydiard, Stephen; Fehily, Brooke; Weir, Gillian; Chin, Aaron; Bartlett, Carole A; Alderson, Jacqueline; Fitzgerald, Melinda

2017-07-01

Negative outcomes of mild traumatic brain injury (mTBI) can be exacerbated by repeated insult. Animal models of repeated closed-head mTBI provide the opportunity to define acute pathological mechanisms as the number of mTBI increases. Furthermore, little is known about the effects of mTBI impact site, and how this may affect brain function. We use a closed head, weight drop model of mTBI that allows head movement following impact, in adult female rats to determine the role of the number and location of mTBI on brain pathology and behaviour. Biomechanical assessment of two anatomically well-defined mTBI impact sites were used, anterior (bregma) and posterior (lambda). Location of the impact had no significant effect on impact forces (450 N), and the weight impact locations were on average 5.4 mm from the desired impact site. No between location vertical linear head kinematic differences were observed immediately following impact, however, in the 300 ms post-impact, significantly higher mean vertical head displacement and velocity were observed in the mTBI lambda trials. Breaches of the blood brain barrier were observed with three mTBI over bregma, associated with immunohistochemical indicators of damage. However, an increased incidence of hairline fractures of the skull and macroscopic haemorrhaging made bregma an unsuitable impact location to model repeated mTBI. Repeated mTBI over lambda did not cause skull fractures and were examined more comprehensively, with outcomes following one, two or three mTBI or sham, delivered at 1 day intervals, assessed on days 1-4. We observe a mild behavioural phenotype, with subtle deficits in cognitive function, associated with no identifiable neuroanatomical or inflammatory changes. However, an increase in lipid peroxidation in a subset of cortical neurons following two mTBI indicates increasing oxidative damage with repeated injury in female rats, supported by increased amyloid precursor protein immunoreactivity with three m

Effects of anesthetics on vesicular monoamine transporter type 2 binding to 18F-FP-(+)-DTBZ: a biodistribution study in rat brain

International Nuclear Information System (INIS)

Chen, Zhengping; Tang, Jie; Liu, Chunyi; Li, Xiaomin; Huang, Hongbo; Xu, Xijie; Yu, Huixin

2016-01-01

Objectives: The in vivo binding analysis of vesicular monoamine transporter type 2 (VMAT2) to radioligand has provided a means of investigating related disorders. Anesthesia is often inevitable when the investigations are performed in animals. In the present study, we tested effects of four commonly-used anesthetics: isoflurane, pentobarbital, chloral hydrate and ketamine, on in vivo VMAT2 binding to 18 F-FP-(+)-DTBZ, a specific VMAT2 radioligand, in rat brain. Methods: The transient equilibrium time window for in vivo binding of 18 F-FP-(+)-DTBZ after a bolus injection was firstly determined. The brain biodistribution studies under anesthetized and awake rats were then performed at the equilibrium time. Standard uptake values (SUVs) of the interest brain regions: the striatum (ST), hippocampus (HP), cortex (CX) and cerebellum (CB) were obtained; and ratios of tissue to cerebellum were calculated. Results: Isoflurane and pentobarbital did not alter distribution of 18 F-FP-(+)-DTBZ in the brain relative to the awake group; neither SUVs nor ratios of ST/CB and HP/CB were altered significantly. Chloral hydrate significantly increased SUVs of all the brain regions, but did not significantly alter ratios of ST/CB and HP/CB. Ketamine significantly increased SUVs of the striatum, hippocampus and cortex, and insignificantly increased the SUV of the cerebellum; consequently, ketamine significantly increased ratios of ST/CB and HP/CB. Conclusions: It is concluded that in vivo VMAT2 binding to 18 F-FP-(+)-DTBZ are not altered by isoflurane and pentobarbital, but altered by chloral hydrate and ketamine. Isoflurane and pentobarbital may be promising anesthetic compounds for investigating in vivo VMAT2 binding. Further studies are warranted to investigate the interactions of anesthetics with VMAT2 binding potential with in vivo PET studies.

Measuring specific receptor binding of a PET radioligand in human brain without pharmacological blockade: The genomic plot.

Science.gov (United States)

Veronese, Mattia; Zanotti-Fregonara, Paolo; Rizzo, Gaia; Bertoldo, Alessandra; Innis, Robert B; Turkheimer, Federico E

2016-04-15

PET studies allow in vivo imaging of the density of brain receptor species. The PET signal, however, is the sum of the fraction of radioligand that is specifically bound to the target receptor and the non-displaceable fraction (i.e. the non-specifically bound radioligand plus the free ligand in tissue). Therefore, measuring the non-displaceable fraction, which is generally assumed to be constant across the brain, is a necessary step to obtain regional estimates of the specific fractions. The nondisplaceable binding can be directly measured if a reference region, i.e. a region devoid of any specific binding, is available. Many receptors are however widely expressed across the brain, and a true reference region is rarely available. In these cases, the nonspecific binding can be obtained after competitive pharmacological blockade, which is often contraindicated in humans. In this work we introduce the genomic plot for estimating the nondisplaceable fraction using baseline scans only. The genomic plot is a transformation of the Lassen graphical method in which the brain maps of mRNA transcripts of the target receptor obtained from the Allen brain atlas are used as a surrogate measure of the specific binding. Thus, the genomic plot allows the calculation of the specific and nondisplaceable components of radioligand uptake without the need of pharmacological blockade. We first assessed the statistical properties of the method with computer simulations. Then we sought ground-truth validation using human PET datasets of seven different neuroreceptor radioligands, where nonspecific fractions were either obtained separately using drug displacement or available from a true reference region. The population nondisplaceable fractions estimated by the genomic plot were very close to those measured by actual human blocking studies (mean relative difference between 2% and 7%). However, these estimates were valid only when mRNA expressions were predictive of protein levels (i

Different sensitivities to competitive inhibition of benzodiazepine receptor binding of {sup 11}C-iomazenil and {sup 11}C-flumazenil in rhesus monkey brain

Energy Technology Data Exchange (ETDEWEB)

Inoue, Osamu; Hosoi, Rie; Kobayashi, Kaoru [Osaka Univ., Suita (Japan). Medical School; Itoh, Takashi; Gee, A.; Suzuki, Kazutoshi

2001-04-01

The in vivo binding kinetics of {sup 11}C-iomazenil were compared with those of {sup 11}C-flumazenil binding in rhesus monkey brain. The monkey was anesthetized with ketamine and intravenously injected with either {sup 11}C-iomazenil or {sup 11}C-flumazenil in combination with the coadministration of different doses of non-radioactive flumazenil (0, 5 and 20 {mu}g/kg). The regional distribution of {sup 11}C-iomazenil in the brain was similar to that of {sup 11}C-flumazenil, but the sensitivity of {sup 11}C-iomazenil binding to competitive inhibition by non-radioactive flumazenil was much less than that of {sup 11}C-flumazenil binding. A significant reduction in {sup 11}C-flumazenil binding in the cerebral cortex was observed with 20 {mu}g/kg of flumazenil, whereas a relatively smaller inhibition of {sup 11}C-iomazenil binding in the same region was observed with the same dose of flumazenil. These results suggest that {sup 11}C-flumazenil may be a superior radiotracer for estimating benzodiazepine receptor occupancy in the intact brain. (author)

Fatty acid binding proteins have the potential to channel dietary fatty acids into enterocyte nuclei.

Science.gov (United States)

Esteves, Adriana; Knoll-Gellida, Anja; Canclini, Lucia; Silvarrey, Maria Cecilia; André, Michèle; Babin, Patrick J

2016-02-01

Intracellular lipid binding proteins, including fatty acid binding proteins (FABPs) 1 and 2, are highly expressed in tissues involved in the active lipid metabolism. A zebrafish model was used to demonstrate differential expression levels of fabp1b.1, fabp1b.2, and fabp2 transcripts in liver, anterior intestine, and brain. Transcription levels of fabp1b.1 and fabp2 in the anterior intestine were upregulated after feeding and modulated according to diet formulation. Immunofluorescence and electron microscopy immunodetection with gold particles localized these FABPs in the microvilli, cytosol, and nuclei of most enterocytes in the anterior intestinal mucosa. Nuclear localization was mostly in the interchromatin space outside the condensed chromatin clusters. Native PAGE binding assay of BODIPY-FL-labeled FAs demonstrated binding of BODIPY-FLC(12) but not BODIPY-FLC(5) to recombinant Fabp1b.1 and Fabp2. The binding of BODIPY-FLC(12) to Fabp1b.1 was fully displaced by oleic acid. In vivo experiments demonstrated, for the first time, that intestinal absorption of dietary BODIPY-FLC(12) was followed by colocalization of the labeled FA with Fabp1b and Fabp2 in the nuclei. These data suggest that dietary FAs complexed with FABPs are able to reach the enterocyte nucleus with the potential to modulate nuclear activity. Copyright © 2016 by the American Society for Biochemistry and Molecular Biology, Inc.

Vaccinia Virus Immunomodulator A46: A Lipid and Protein-Binding Scaffold for Sequestering Host TIR-Domain Proteins.

Directory of Open Access Journals (Sweden)

Sofiya Fedosyuk

2016-12-01

Full Text Available Vaccinia virus interferes with early events of the activation pathway of the transcriptional factor NF-kB by binding to numerous host TIR-domain containing adaptor proteins. We have previously determined the X-ray structure of the A46 C-terminal domain; however, the structure and function of the A46 N-terminal domain and its relationship to the C-terminal domain have remained unclear. Here, we biophysically characterize residues 1-83 of the N-terminal domain of A46 and present the X-ray structure at 1.55 Å. Crystallographic phases were obtained by a recently developed ab initio method entitled ARCIMBOLDO_BORGES that employs tertiary structure libraries extracted from the Protein Data Bank; data analysis revealed an all β-sheet structure. This is the first such structure solved by this method which should be applicable to any protein composed entirely of β-sheets. The A46(1-83 structure itself is a β-sandwich containing a co-purified molecule of myristic acid inside a hydrophobic pocket and represents a previously unknown lipid-binding fold. Mass spectrometry analysis confirmed the presence of long-chain fatty acids in both N-terminal and full-length A46; mutation of the hydrophobic pocket reduced the lipid content. Using a combination of high resolution X-ray structures of the N- and C-terminal domains and SAXS analysis of full-length protein A46(1-240, we present here a structural model of A46 in a tetrameric assembly. Integrating affinity measurements and structural data, we propose how A46 simultaneously interferes with several TIR-domain containing proteins to inhibit NF-κB activation and postulate that A46 employs a bipartite binding arrangement to sequester the host immune adaptors TRAM and MyD88.

Lipid microbubbles as a vehicle for targeted drug delivery using focused ultrasound-induced blood–brain barrier opening

Science.gov (United States)

Sierra, Carlos; Acosta, Camilo; Chen, Cherry; Wu, Shih-Ying; Karakatsani, Maria E; Bernal, Manuel

2016-01-01

Focused ultrasound in conjunction with lipid microbubbles has fully demonstrated its ability to induce non-invasive, transient, and reversible blood–brain barrier opening. This study was aimed at testing the feasibility of our lipid-coated microbubbles as a vector for targeted drug delivery in the treatment of central nervous system diseases. These microbubbles were labeled with the fluorophore 5-dodecanoylaminfluorescein. Focused ultrasound targeted mouse brains in vivo in the presence of these microbubbles for trans-blood–brain barrier delivery of 5-dodecanoylaminfluorescein. This new approach, compared to previously studies of our group, where fluorescently labeled dextrans and microbubbles were co-administered, represents an appreciable improvement in safety outcome and targeted drug delivery. This novel technique allows the delivery of 5-dodecanoylaminfluorescein at the region of interest unlike the alternative of systemic exposure. 5-dodecanoylaminfluorescein delivery was assessed by ex vivo fluorescence imaging and by in vivo transcranial passive cavitation detection. Stable and inertial cavitation doses were quantified. The cavitation dose thresholds for estimating, a priori, successful targeted drug delivery were, for the first time, identified with inertial cavitation were concluded to be necessary for successful delivery. The findings presented herein indicate the feasibility and safety of the proposed microbubble-based targeted drug delivery and that, if successful, can be predicted by cavitation detection in vivo. PMID:27278929

Serotoninergic receptors in brain tissue: properties and identification of various 3H-ligand binding sites in vitro

International Nuclear Information System (INIS)

Leysen, J.E.

1981-01-01

In vitro binding studies to serotoninergic receptors were performed using 3 H-LSD, 3 H-5-HT and 3 H-spiperone. An overwiew is given on findings using these three ligands with respect to the following: localization of specific binding sites, in various animal species, the regional distribution in the brain and periphery, the subcellular and cellular distribution. Properties of the binding sites, influence of the composition of the assay medium, binding kinetic properties, receptor regulation in vivo. Identity of the binding sites, differences between site for various 3 H-ligands, pharmacological specificity of the membranous binding sites, chemical composition of the macromolecular complex constituting the binding site. Function of the receptor. Binding affinities of 44 compounds were measured in binding assays using 3 H-spiperone and 3 H-LSD with rat frontal cortex membrane preparations and using 3 H-5-HT and 3 H-LSD with rat hippocampal membrane preparations

[3]tetrahydrotrazodone binding. Association with serotonin binding sites

International Nuclear Information System (INIS)

Kendall, D.A.; Taylor, D.P.; Enna, S.J.

1983-01-01

High (17 nM) and low (603 nM) affinity binding sites for [ 3 ]tetrahydrotrazodone ([ 3 ] THT), a biologically active analogue of trazodone, have been identified in rat brain membranes. The substrate specificity, concentration, and subcellular and regional distributions of these sites suggest that they may represent a component of the serotonin transmitter system. Pharmacological analysis of [ 3 ]THT binding, coupled with brain lesion and drug treatment experiments, revealed that, unlike other antidepressants, [ 3 ] THT does not attach to either a biogenic amine transporter or serotonin binding sites. Rather, it would appear that [ 3 ]THT may be an antagonist ligand for the serotonin binding site. This probe may prove of value in defining the mechanism of action of trazodone and in further characterizing serotonin receptors

2.5D Representations Combining in vivo 3D MRI and ex vivo 2D MSI Approaches to Study the Lipid Distribution in the Whole Sheep Brain

OpenAIRE

Labas , Valérie; Teixeira-Gomes , Ana Paula; Andersson , Frédéric; Ménigot , Sébastien; Batailler , Martine; Adriaensen , Hans; Migaud , Martine; Chaillou , Elodie

2015-01-01

National audience; Mass Spectrometry Imaging (MSI) provides easily high spatially resolved masses allowing characterization of endogenous lipids. These latter constitute about 70% of the composition of the white matter of the brain which can be implicated in developmental and/or cognitive troubles. In order to examine the molecular distribution of lipids in whole sheep brain, and especially in white/grey matter, we combined in vivo and ex vivo images, obtained in the same animals, using Magne...

A comprehensive classification system for lipids

NARCIS (Netherlands)

Fahy, E.; Subramaniam, S.; Brown, H.A.; Glass, C.K.; Merrill, A.H.; Murphy, R.C.; Raetz, C.R.H.; Russell, D.W.; Seyama, Y.; Shaw, W.; Shimizu, T.; Spener, F.; van Meer, G.|info:eu-repo/dai/nl/068570368; VanNieuwenhze, M.S.; White, S.H.|info:eu-repo/dai/nl/304843539; Witztum, J.; Dennis, E.A.

2005-01-01

Lipids are produced, transported, and recognized by the concerted actions of numerous enzymes, binding proteins, and receptors. A comprehensive analysis of lipid molecules, “lipidomics,” in the context of genomics and proteomics is crucial to understanding cellular physiology and pathology;

Identification and properties of very high affinity brain membrane-binding sites for a neurotoxic phospholipase from the taipan venom

International Nuclear Information System (INIS)

Lambeau, G.; Barhanin, J.; Schweitz, H.; Qar, J.; Lazdunski, M.

1989-01-01

Four new monochain phospholipases were purified from the Oxyuranus scutellatus (taipan) venom. Three of them were highly toxic when injected into mice brain. One of these neurotoxic phospholipases, OS2, was iodinated and used in binding experiments to demonstrate the presence of two families of specific binding sites in rat brain synaptic membranes. The affinities were exceptionally high, Kd1 = 1.5 +/- 0.5 pM and Kd2 = 45 +/- 10 pM, and the maximal binding capacities were Bmax 1 = 1 +/- 0.4 and Bmax 2 = 3 +/- 0.5 pmol/mg of protein. Both binding sites were sensitive to proteolysis and demonstrated to be located on proteins of Mr 85,000-88,000 and 36,000-51,000 by cross-linking and photoaffinity labeling techniques. The binding of 125 I-OS2 to synaptic membranes was dependent on Ca2+ ions and enhanced by Zn2+ ions which inhibit phospholipase activity. Competition experiments have shown that, except for beta-bungarotoxin, a number of known toxic snake or bee phospholipases have very high affinities for the newly identified binding sites. A good correlation (r = 0.80) was observed between toxicity and affinity but not between phospholipase activity and affinity

Sex hormone binding globulin, free estradiol index, and lipid profiles in girls with precocious puberty

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Hyun-Wook Chae

2013-06-01

Full Text Available PurposeSex hormone-binding globulin (SHBG modulates the availability of biologically active free sex hormones. The regulatory role of SHBG might be important in the relationship between hormone levels and the modification of lipid profiles in girls with precocious puberty. However, few studies have evaluated the relationship of SHBG, free estradiol index (FEI, and lipid levels in these girls.MethodsOne hundred and nine girls less than 8 years of age with pubertal development were enrolled. FEI was calculated with SHBG and estradiol (E2. We analyzed SHBG between peak luteinizing hormone (LH≥5 (IU/L (group 1 and LH<5 (IU/L (group 2 through a gonadotropin releasing hormone stimulation test.ResultsBody mass index (BMI standard deviation score (SDS was higher in group 2 than in group 1 (P=0.004. Serum SHBG levels did not differ and FEI was not higher in group 1 (P=0.122. Serum cholesterol, HDL, and LDL did not differ; however, triglyceride levels were higher in group 2 (P=0.023. SHBG was negatively correlated with bone age advancement, BMI, BMI SDS, and FEI, and was positively correlated with HDL. However, SHBG was not correlated with E2 or peak LH.ConclusionSerum SHBG itself might not be associated with precocious puberty in girls, but it might be related to BMI and lipid profiles. Further studies are needed to reveal the relationship between sex hormone and obesity in girls with precocious puberty.

Water extractable phytochemicals from Capsicum pubescens (tree pepper) inhibit lipid peroxidation induced by different pro-oxidant agents in brain

International Nuclear Information System (INIS)

Oboh, G.; Rocha, J.B.T.

2006-03-01

Reactive oxygen species (ROS) is the cause of neurodegenerative disorders such as Lou Gehrig's disease, Parkinson's disease and Huntington's disease; one practical way to prevent and manage neurodegenerative diseases is through the eating of food rich in antioxidants (dietary means). In this study, the antioxidant and neuroprotective properties of aqueous extract of ripe and unripe Capsicum pubescens (popularly known as tree pepper) on different pro-oxidant induced lipid peroxidation in Rat's brain (in vitro) is been investigated. Aqueous extract of freshly harvested pepper was prepared, and the total phenol content, vitamin C, ferric reducing antioxidant property (FRAP) and Fe (II) chelating ability was determined. In addition, the ability of the extracts to protect the Rat's brain against some pro-oxidant FeSO 4 , Sodium nitroprusside and Quinolinic acid) - induced oxidative stress was also determined. The results of the study revealed that ripe Capsicum pubescens had a significantly higher (P 2 O 2 induced decomposition of deoxyribose. Therefore, ripe and unripe Capsicum pubescens would inhibit lipid peroxidation in vitro. However, the ripe potent was a more potent inhibitor of lipid peroxidation, which is probably due to its higher vitamin C and phenol content, reducing power and Fe (II) chelating ability. (author)

Microspectroscopy (μFTIR) reveals co-localization of lipid oxidation and amyloid plaques in human Alzheimer disease brains.

Science.gov (United States)

Benseny-Cases, Núria; Klementieva, Oxana; Cotte, Marine; Ferrer, Isidre; Cladera, Josep

2014-12-16

Amyloid peptides are the main component of one of the characteristic pathological hallmarks of Alzheimer's disease (AD): senile plaques. According to the amyloid cascade hypothesis, amyloid peptides may play a central role in the sequence of events that leads to neurodegeneration. However, there are other factors, such as oxidative stress, that may be crucial for the development of the disease. In the present paper, we show that it is possible, by using Fourier tranform infrared (FTIR) microscopy, to co-localize amyloid deposits and lipid peroxidation in tissue slides from patients affected by Alzheimer's disease. Plaques and lipids can be analyzed in the same sample, making use of the characteristic infrared bands for peptide aggregation and lipid oxidation. The results show that, in samples from patients diagnosed with AD, the plaques and their immediate surroundings are always characterized by the presence of oxidized lipids. As for samples from non-AD individuals, those without amyloid plaques show a lower level of lipid oxidation than AD individuals. However, it is known that plaques can be detected in the brains of some non-AD individuals. Our results show that, in such cases, the lipid in the plaques and their surroundings display oxidation levels that are similar to those of tissues with no plaques. These results point to lipid oxidation as a possible key factor in the path that goes from showing the typical neurophatological hallmarks to suffering from dementia. In this process, the oxidative power of the amyloid peptide, possibly in the form of nonfibrillar aggregates, could play a central role.

Lipid composition of microdomains is altered in neuronopathic Gaucher disease sheep brain and spleen.

Science.gov (United States)

Hein, Leanne K; Rozaklis, Tina; Adams, Melissa K; Hopwood, John J; Karageorgos, Litsa

2017-07-01

Gaucher disease is a lysosomal storage disorder caused by a deficiency in glucocerebrosidase activity that leads to accumulation of glucosylceramide and glucosylsphingosine. Membrane raft microdomains are discrete, highly organized microdomains with a unique lipid composition that provide the necessary environment for specific protein-lipid and protein-protein interactions to take place. In this study we purified detergent resistant membranes (DRM; membrane rafts) from the occipital cortex and spleen from sheep affected with acute neuronopathic Gaucher disease and wild-type controls. We observed significant increases in the concentrations of glucosylceramide, hexosylsphingosine, BMP and gangliosides and decreases in the percentage of cholesterol and phosphatidylcholine leading to an altered DRM composition. Altered sphingolipid/cholesterol homeostasis would dramatically disrupt DRM architecture making them less ordered and more fluid. In addition, significant changes in the length and degree of lipid saturation within the DRM microdomains in the Gaucher brain were also observed. As these DRM microdomains are involved in many cellular events, an imbalance or disruption of the cell membrane homeostasis may impair normal cell function. This disruption of membrane raft microdomains and imbalance within the environment of cellular membranes of neuronal cells may be a key factor in initiating a cascade process leading to neurodegeneration. Copyright © 2017 Elsevier Inc. All rights reserved.

Fatty acid binding proteins have the potential to channel dietary fatty acids into enterocyte nuclei[S

Science.gov (United States)

Esteves, Adriana; Knoll-Gellida, Anja; Canclini, Lucia; Silvarrey, Maria Cecilia; André, Michèle; Babin, Patrick J.

2016-01-01

Intracellular lipid binding proteins, including fatty acid binding proteins (FABPs) 1 and 2, are highly expressed in tissues involved in the active lipid metabolism. A zebrafish model was used to demonstrate differential expression levels of fabp1b.1, fabp1b.2, and fabp2 transcripts in liver, anterior intestine, and brain. Transcription levels of fabp1b.1 and fabp2 in the anterior intestine were upregulated after feeding and modulated according to diet formulation. Immunofluorescence and electron microscopy immunodetection with gold particles localized these FABPs in the microvilli, cytosol, and nuclei of most enterocytes in the anterior intestinal mucosa. Nuclear localization was mostly in the interchromatin space outside the condensed chromatin clusters. Native PAGE binding assay of BODIPY-FL-labeled FAs demonstrated binding of BODIPY-FLC12 but not BODIPY-FLC5 to recombinant Fabp1b.1 and Fabp2. The binding of BODIPY-FLC12 to Fabp1b.1 was fully displaced by oleic acid. In vivo experiments demonstrated, for the first time, that intestinal absorption of dietary BODIPY-FLC12 was followed by colocalization of the labeled FA with Fabp1b and Fabp2 in the nuclei. These data suggest that dietary FAs complexed with FABPs are able to reach the enterocyte nucleus with the potential to modulate nuclear activity. PMID:26658423

The role of thyroid hormones in regulating of fatty acid spectrum of brain lipids: ontogenetic aspect

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Rodynskiy A.G.

2016-05-01

Full Text Available In experiments on rats of three age groups the role of thyroid hormones in the regulation of fatty acid spectrum of cortical and hippocampus lipids was studied. It was found that on the background of decreased thyroid status content of polyunsaturated fractions of free fatty acids, significantly changed depending on the age of the animals. In particular, in juvenile rats hypothyroidism was accompanied by a decrease almost twice the number of pentacodan acid decreased lipids viscosity in neurocortex. In old rats reduce of pentacodan acid in the cortex (38% was supplemented by significant (77% decrease in linoleic and linolenic acids. Unlike the two age groups deficiency of thyroid hormones in young animals caused accumulation of free polyunsatarated fatty acids (C18: 2.3 in the cerebral cortex by 74%, which may be associated with a decrease of this fraction in fatty acid spectrum of lipids and increase of viscosity properties of the membranes. These restruc­turing may be associated with modulation of synaptic transmission of specific neurotransmitter systems in the brain.

Binding kinetics of 11C-N-methyl piperidyl benzilate (11C-NMPB) in a rhesus monkey brain using the cerebellum as a reference region

International Nuclear Information System (INIS)

Itoh, Takashi; Tanaka, Masayasu; Suzuki, Kasutoshi; Kobayashi, Kaoru; Inoue, Osamu

2005-01-01

The binding kinetics of' 11 C-N-methyl piperidyl benzilate ( 11 C-NMPB) in rhesus monkey brain were studied using animal positron emission tomography (PET) (SHR2000). This study is intended to assess the validity of the method using the cerebellum as a reference region, and to evaluate the effects of anesthesia on 11 C -NMPB binding. Two monkeys, anesthetized with ketamine, received intravenous 11 C-NMPB alone (370-760 MBq, 11 C-NMPB accumulated densely in the striatum and cerebral cortex with time. In contrast, the tracer accumulation significantly decreased with increased doses of nonradioactive NMPB. In the cerebellum, on the other hand, the accumulation of 11 C-NMPB remained low and the tracer was slowly eliminated from the brain following the injection. 11 C-NMPB binding in the cerebellum was barely affected by the increased dose of nonradioactive NMPB. We thus concluded that the specific 11 C-NMPB binding was negligible in the cerebellum, and performed simplified evaluation of 11 C-NMPB binding in each brain region by a graphical method using the cerebellum as a reference region. PET was conducted 26 times, in total both in ketamine-anesthetized and awake monkeys (n=3 each). Measurements of 11 C-NMPB binding showed good run-to-run reproducibility within individual animals. When 11 C-NMPB binding was compared between ketamine-treated and awake animals, a significant increase in 11 C-NMPB binding was observed in the striatum but not in other brain regions of ketamine-treated animals. (author)

The Mammalian "Obesogen" Tributyltin Targets Hepatic Triglyceride Accumulation and the Transcriptional Regulation of Lipid Metabolism in the Liver and Brain of Zebrafish.

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Angeliki Lyssimachou

Full Text Available Recent findings indicate that different Endocrine Disrupting Chemicals (EDCs interfere with lipid metabolic pathways in mammals and promote fat accumulation, a previously unknown site of action for these compounds. The antifoulant and environmental pollutant tributyltin (TBT, which causes imposex in gastropod snails, induces an "obesogenic" phenotype in mammals, through the activation of the nuclear receptors retinoid X receptor (RXR and peroxisome proliferator-activated receptor gamma (PPARγ. In teleosts, the effects of TBT on the lipid metabolism are poorly understood, particularly following exposure to low, environmental concentrations. In this context, the present work shows that exposure of zebrafish to 10 and 50 ng/L of TBT (as Sn from pre-hatch to 9 months of age alters the body weight, condition factor, hepatosomatic index and hepatic triglycerides in a gender and dose related manner. Furthermore, TBT modulated the transcription of key lipid regulating factors and enzymes involved in adipogenesis, lipogenesis, glucocorticoid metabolism, growth and development in the brain and liver of exposed fish, revealing sexual dimorphic effects in the latter. Overall, the present study shows that the model mammalian obesogen TBT interferes with triglyceride accumulation and the transcriptional regulation of lipid metabolism in zebrafish and indentifies the brain lipogenic transcription profile of fish as a new target of this compound.

The Mammalian "Obesogen" Tributyltin Targets Hepatic Triglyceride Accumulation and the Transcriptional Regulation of Lipid Metabolism in the Liver and Brain of Zebrafish.

Science.gov (United States)

Lyssimachou, Angeliki; Santos, Joana G; André, Ana; Soares, Joana; Lima, Daniela; Guimarães, Laura; Almeida, C Marisa R; Teixeira, Catarina; Castro, L Filipe C; Santos, Miguel M

2015-01-01

Recent findings indicate that different Endocrine Disrupting Chemicals (EDCs) interfere with lipid metabolic pathways in mammals and promote fat accumulation, a previously unknown site of action for these compounds. The antifoulant and environmental pollutant tributyltin (TBT), which causes imposex in gastropod snails, induces an "obesogenic" phenotype in mammals, through the activation of the nuclear receptors retinoid X receptor (RXR) and peroxisome proliferator-activated receptor gamma (PPARγ). In teleosts, the effects of TBT on the lipid metabolism are poorly understood, particularly following exposure to low, environmental concentrations. In this context, the present work shows that exposure of zebrafish to 10 and 50 ng/L of TBT (as Sn) from pre-hatch to 9 months of age alters the body weight, condition factor, hepatosomatic index and hepatic triglycerides in a gender and dose related manner. Furthermore, TBT modulated the transcription of key lipid regulating factors and enzymes involved in adipogenesis, lipogenesis, glucocorticoid metabolism, growth and development in the brain and liver of exposed fish, revealing sexual dimorphic effects in the latter. Overall, the present study shows that the model mammalian obesogen TBT interferes with triglyceride accumulation and the transcriptional regulation of lipid metabolism in zebrafish and indentifies the brain lipogenic transcription profile of fish as a new target of this compound.

Influence of alcoholism and cholesterol on TSPO binding in brain: PET [11C]PBR28 studies in humans and rodents.

Science.gov (United States)

Kim, Sung Won; Wiers, Corinde E; Tyler, Ryan; Shokri-Kojori, Ehsan; Jang, Yeon Joo; Zehra, Amna; Freeman, Clara; Ramirez, Veronica; Lindgren, Elsa; Miller, Gregg; Cabrera, Elizabeth A; Stodden, Tyler; Guo, Min; Demiral, Şükrü B; Diazgranados, Nancy; Park, Luke; Liow, Jeih-San; Pike, Victor; Morse, Cheryl; Vendruscolo, Leandro F; Innis, Robert B; Koob, George F; Tomasi, Dardo; Wang, Gene-Jack; Volkow, Nora D

2018-05-03

Neuroinflammation appears to contribute to neurotoxicity observed with heavy alcohol consumption. To assess whether chronic alcohol results in neuroinflammation we used PET and [ 11 C]PBR28, a ligand that binds to the 18-kDa translocator protein (TSPO), to compare participants with an alcohol use disorder (AUD: n = 19) with healthy controls (HC: n = 17), and alcohol-dependent (n = 9) with -nondependent rats (n = 10). Because TSPO is implicated in cholesterol's transport for steroidogenesis, we investigated whether plasma cholesterol levels influenced [ 11 C]PBR28 binding. [ 11 C]PBR28 binding did not differ between AUD and HC. However, when separating by TSPO genotype rs6971, we showed that medium-affinity binders AUD participants showed lower [ 11 C]PBR28 binding than HC in regions of interest (whole brain, gray and white matter, hippocampus, and thalamus), but no group differences were observed in high-affinity binders. Cholesterol levels inversely correlated with brain [ 11 C]PBR28 binding in combined groups, due to a correlation in AUD participants. In rodents, we observed no differences in brain [ 11 C]PBR28 uptake between alcohol-dependent and -nondependent rats. These findings, which are consistent with two previous [ 11 C]PBR28 PET studies, may indicate lower activation of microglia in AUD, whereas failure to observe alcohol effects in the rodent model indicate that species differences do not explain the discrepancy with prior rodent autoradiographic studies reporting increases in TSPO binding with chronic alcohol. However, reduced binding in AUD participants could also reflect competition from endogenous TSPO ligands such as cholesterol; and since the rs6971 polymorphism affects the cholesterol-binding domain of TSPO this could explain why differences were observed only in medium-affinity binders.

Evolution of the duplicated intracellular lipid-binding protein genes of teleost fishes.

Science.gov (United States)

Venkatachalam, Ananda B; Parmar, Manoj B; Wright, Jonathan M

2017-08-01

Increasing organismal complexity during the evolution of life has been attributed to the duplication of genes and entire genomes. More recently, theoretical models have been proposed that postulate the fate of duplicated genes, among them the duplication-degeneration-complementation (DDC) model. In the DDC model, the common fate of a duplicated gene is lost from the genome owing to nonfunctionalization. Duplicated genes are retained in the genome either by subfunctionalization, where the functions of the ancestral gene are sub-divided between the sister duplicate genes, or by neofunctionalization, where one of the duplicate genes acquires a new function. Both processes occur either by loss or gain of regulatory elements in the promoters of duplicated genes. Here, we review the genomic organization, evolution, and transcriptional regulation of the multigene family of intracellular lipid-binding protein (iLBP) genes from teleost fishes. Teleost fishes possess many copies of iLBP genes owing to a whole genome duplication (WGD) early in the teleost fish radiation. Moreover, the retention of duplicated iLBP genes is substantially higher than the retention of all other genes duplicated in the teleost genome. The fatty acid-binding protein genes, a subfamily of the iLBP multigene family in zebrafish, are differentially regulated by peroxisome proliferator-activated receptor (PPAR) isoforms, which may account for the retention of iLBP genes in the zebrafish genome by the process of subfunctionalization of cis-acting regulatory elements in iLBP gene promoters.

Membrane morphology is actively transformed by covalent binding of the protein Atg8 to PE-lipids.

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Roland L Knorr

Full Text Available Autophagy is a cellular degradation pathway involving the shape transformation of lipid bilayers. During the onset of autophagy, the water-soluble protein Atg8 binds covalently to phosphatdylethanolamines (PEs in the membrane in an ubiquitin-like reaction coupled to ATP hydrolysis. We reconstituted the Atg8 conjugation system in giant and nm-sized vesicles with a minimal set of enzymes and observed that formation of Atg8-PE on giant vesicles can cause substantial tubulation of membranes even in the absence of Atg12-Atg5-Atg16. Our findings show that ubiquitin-like processes can actively change properties of lipid membranes and that membrane crowding by proteins can be dynamically regulated in cells. Furthermore we provide evidence for curvature sorting of Atg8-PE. Curvature generation and sorting are directly linked to organelle shapes and, thus, to biological function. Our results suggest that a positive feedback exists between the ubiquitin-like reaction and the membrane curvature, which is important for dynamic shape changes of cell membranes, such as those involved in the formation of autophagosomes.

Melittin binding to mixed phosphatidylglycerol/phosphatidylcholine membranes

Energy Technology Data Exchange (ETDEWEB)

Beschiaschvili, G.; Seelig, J. (Univ. of Basel (Switzerland))

1990-01-09

The binding of bee venom melittin to negatively charged unilamellar vesicles and planar lipid bilayers composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol (POPG) was studied with circular dichroism and deuterium NMR spectroscopy. The melittin binding isotherm was measured for small unilamellar vesicles containing 10 or 20 mol % POPG. Due to electrostatic attraction, binding of the positively charged melittin was much enhanced as compared to the binding to neutral lipid vesicles. However, after correction for electrostatic effects by means of the Gouy-Chapman theory, all melittin binding isotherms could be described by a partition Kp = (4.5 +/- 0.6) x 10(4) M-1. It was estimated that about 50% of the total melittin surface was embedded in a hydrophobic environment. The melittin partition constant for small unilamellar vesicles was by a factor of 20 larger than that of planar bilayers and attests to the tighter lipid packing in the nonsonicated bilayers. Deuterium NMR studies were performed with coarse lipid dispersions. Binding of melittin to POPC/POPG (80/20 mol/mol) membranes caused systematic changes in the conformation of the phosphocholine and phosphoglycerol head groups which were ascribed to the influence of electrostatic charge on the choline dipole. While the negative charge of phosphatidylglycerol moved the N+ end of the choline -P-N+ dipole toward the bilayer interior, the binding of melittin reversed this effect and rotated the N+ end toward the aqueous phase. No specific melittin-POPG complexes could be detected. The phosphoglycerol head group was less affected by melittin binding than its choline counterpart.

Melittin binding to mixed phosphatidylglycerol/phosphatidylcholine membranes

International Nuclear Information System (INIS)

Beschiaschvili, G.; Seelig, J.

1990-01-01

The binding of bee venom melittin to negatively charged unilamellar vesicles and planar lipid bilayers composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol (POPG) was studied with circular dichroism and deuterium NMR spectroscopy. The melittin binding isotherm was measured for small unilamellar vesicles containing 10 or 20 mol % POPG. Due to electrostatic attraction, binding of the positively charged melittin was much enhanced as compared to the binding to neutral lipid vesicles. However, after correction for electrostatic effects by means of the Gouy-Chapman theory, all melittin binding isotherms could be described by a partition Kp = (4.5 +/- 0.6) x 10(4) M-1. It was estimated that about 50% of the total melittin surface was embedded in a hydrophobic environment. The melittin partition constant for small unilamellar vesicles was by a factor of 20 larger than that of planar bilayers and attests to the tighter lipid packing in the nonsonicated bilayers. Deuterium NMR studies were performed with coarse lipid dispersions. Binding of melittin to POPC/POPG (80/20 mol/mol) membranes caused systematic changes in the conformation of the phosphocholine and phosphoglycerol head groups which were ascribed to the influence of electrostatic charge on the choline dipole. While the negative charge of phosphatidylglycerol moved the N+ end of the choline -P-N+ dipole toward the bilayer interior, the binding of melittin reversed this effect and rotated the N+ end toward the aqueous phase. No specific melittin-POPG complexes could be detected. The phosphoglycerol head group was less affected by melittin binding than its choline counterpart

Nicotinic cholinergic receptor in brain detected by binding of. cap alpha. -(/sup 3/H)bungarotoxin

Energy Technology Data Exchange (ETDEWEB)

Eterovic, V A; Bennett, E L

1974-01-01

..cap alpha..-(/sup 3/H)bungarotoxin was prepared by catalytic reduction of iodinated ..cap alpha..-bungarotoxin with tritium gas. Crude mitochondrial fraction from rat cerebral cortex bound 40 x 10/sup -15/ to 60 x 10/sup -15/ moles of ..cap alpha..-(/sup 3/H)bungarotoxin per mg of protein. This binding was reduced by 50% in the presence of approx. 10/sup -6/ M d-tubocurarine or nicotine, 10/sup -5/ M acetylcholine, 10/sup -4/ M carbamylcholine or decamethonium or 10/sup -3/ M atropine. Hexamethonium and eserine were the least effective of the drugs tested. Crude mitochondrial fraction was separated into myelin, nerve endings, and mitochondria. The highest binding of toxin per mg of protein was found in nerve endings, as well as the greatest inhibition of toxin binding by d-tubocurarine. Binding of ..cap alpha..-(/sup 3/H)bungarotoxin to membranes obtained by osmotic shock of the crude mitochondrial fraction indicates that the receptor for the toxin is membrane bound. /sup 125/I-labeled ..cap alpha..-bungarotoxin, prepared with Na/sup 125/I and chloramine T, was highly specific for the acetylcholine receptor in diaphragm, however, it was less specific and less reliable than ..cap alpha..-(/sup 3/H)bungarotoxin in brain. It is concluded that a nicotinic cholinergic receptor exists in brain, and that ..cap alpha..-(/sup 3/H)bungarotoxin is a suitable probe for this receptor.

Inhibition of HCV replication by oxysterol-binding protein-related protein 4 (ORP4 through interaction with HCV NS5B and alteration of lipid droplet formation.

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In-Woo Park

Full Text Available Hepatitis C virus (HCV RNA replication involves complex interactions among the 3'x RNA element within the HCV 3' untranslated region, viral and host proteins. However, many of the host proteins remain unknown. In this study, we devised an RNA affinity chromatography /2D/MASS proteomics strategy and identified nine putative 3' X-associated host proteins; among them is oxysterol-binding protein-related protein 4 (ORP4, a cytoplasmic receptor for oxysterols. We determined the relationship between ORP4 expression and HCV replication. A very low level of constitutive ORP4 expression was detected in hepatocytes. Ectopically expressed ORP4 was detected in the endoplasmic reticulum and inhibited luciferase reporter gene expression in HCV subgenomic replicon cells and HCV core expression in JFH-1-infected cells. Expression of ORP4S, an ORP4 variant that lacked the N-terminal pleckstrin-homology domain but contained the C-terminal oxysterol-binding domain also inhibited HCV replication, pointing to an important role of the oxysterol-binding domain in ORP4-mediated inhibition of HCV replication. ORP4 was found to associate with HCV NS5B and its expression led to inhibition of the NS5B activity. ORP4 expression had little effect on intracellular lipid synthesis and secretion, but it induced lipid droplet formation in the context of HCV replication. Taken together, these results demonstrate that ORP4 is a negative regulator of HCV replication, likely via interaction with HCV NS5B in the replication complex and regulation of intracellular lipid homeostasis. This work supports the important role of lipids and their metabolism in HCV replication and pathogenesis.

Effect of anchor positioning on binding and diffusion of elongated 3D DNA nanostructures on lipid membranes

International Nuclear Information System (INIS)

Khmelinskaia, Alena; Franquelim, Henri G; Petrov, Eugene P; Schwille, Petra

2016-01-01

DNA origami is a state-of-the-art technology that enables the fabrication of nano-objects with defined shapes, to which functional moieties, such as lipophilic anchors, can be attached with a nanometre scale precision. Although binding of DNA origami to lipid membranes has been extensively demonstrated, the specific requirements necessary for membrane attachment are greatly overlooked. Here, we designed a set of amphipathic rectangular-shaped DNA origami structures with varying placement and number of chol-TEG anchors used for membrane attachment. Single- and multiple-cholesteryl-modified origami nanostructures were produced and studied in terms of their membrane localization, density and dynamics. We show that the positioning of at least two chol-TEG moieties near the corners is essential to ensure efficient membrane binding of large DNA nanostructures. Quantitative fluorescence correlation spectroscopy data further confirm that increasing the number of corner-positioned chol-TEG anchors lowers the dynamics of flat DNA origami structures on freestanding membranes. Taken together, our approach provides the first evidence of the importance of the location in addition to the number of hydrophobic moieties when rationally designing minimal DNA nanostructures with controlled membrane binding. (paper)

Identification and properties of very high affinity brain membrane-binding sites for a neurotoxic phospholipase from the taipan venom

Energy Technology Data Exchange (ETDEWEB)

Lambeau, G.; Barhanin, J.; Schweitz, H.; Qar, J.; Lazdunski, M. (Centre de Biochimie, Nice (France))

1989-07-05

Four new monochain phospholipases were purified from the Oxyuranus scutellatus (taipan) venom. Three of them were highly toxic when injected into mice brain. One of these neurotoxic phospholipases, OS2, was iodinated and used in binding experiments to demonstrate the presence of two families of specific binding sites in rat brain synaptic membranes. The affinities were exceptionally high, Kd1 = 1.5 +/- 0.5 pM and Kd2 = 45 +/- 10 pM, and the maximal binding capacities were Bmax 1 = 1 +/- 0.4 and Bmax 2 = 3 +/- 0.5 pmol/mg of protein. Both binding sites were sensitive to proteolysis and demonstrated to be located on proteins of Mr 85,000-88,000 and 36,000-51,000 by cross-linking and photoaffinity labeling techniques. The binding of {sup 125}I-OS2 to synaptic membranes was dependent on Ca2+ ions and enhanced by Zn2+ ions which inhibit phospholipase activity. Competition experiments have shown that, except for beta-bungarotoxin, a number of known toxic snake or bee phospholipases have very high affinities for the newly identified binding sites. A good correlation (r = 0.80) was observed between toxicity and affinity but not between phospholipase activity and affinity.

Differentiation of human keratinocytes: changes in lipid synthesis, plasma membrane lipid composition, and 125I-EGF binding upon administration of 25-hydroxycholesterol and mevinolin

International Nuclear Information System (INIS)

Ponec, M.; Kempenaar, J.; Weerheim, A.; Boonstra, J.

1987-01-01

We have studied the relationship between differentiation capacity, plasma membrane composition, and epidermal growth factor (EGF) receptor expression of normal keratinocytes in vitro. The plasma membrane composition of the cells was modulated experimentally by cholesterol depletion, using specific inhibitors of cholesterol synthesis, such as 25-hydroxycholesterol and mevinolin. Exposure of the cells towards these inhibitors resulted in a drastic decrease of cholesterol biosynthesis, as determined from 14 C-acetate incorporation into the various lipid fractions. This effect on cholesterol biosynthesis was reflected by changes in plasma membrane composition, as determined by lipid analysis of isolated plasma membrane fractions, these resulting in a decreased cholesterol-phospholipid ratio. The experimental modulation of plasma membrane composition by 25-hydroxycholesterol or mevinolin were accompanied by a decreased cornified envelope formation and by high expression of EGF binding sites. These phenomena were more pronounced in cells induced to differentiate by exposure of cells grown under low Ca2+ to normal Ca2+ concentrations, as compared to cells grown persistently under low Ca2+ concentrations. These results suggest a close correlation between plasma membrane composition, differentiation capacity, and EGF receptor expression

The Mediator Complex and Lipid Metabolism.

Science.gov (United States)

Zhang, Yi; Xiaoli; Zhao, Xiaoping; Yang, Fajun

2013-03-01

The precise control of gene expression is essential for all biological processes. In addition to DNA-binding transcription factors, numerous transcription cofactors contribute another layer of regulation of gene transcription in eukaryotic cells. One of such transcription cofactors is the highly conserved Mediator complex, which has multiple subunits and is involved in various biological processes through directly interacting with relevant transcription factors. Although the current understanding on the biological functions of Mediator remains incomplete, research in the past decade has revealed an important role of Mediator in regulating lipid metabolism. Such function of Mediator is dependent on specific transcription factors, including peroxisome proliferator-activated receptor-gamma (PPARγ) and sterol regulatory element-binding proteins (SREBPs), which represent the master regulators of lipid metabolism. The medical significance of these findings is apparent, as aberrant lipid metabolism is intimately linked to major human diseases, such as type 2 diabetes and cardiovascular disease. Here, we briefly review the functions and molecular mechanisms of Mediator in regulation of lipid metabolism.

A new optimized formulation of cationic solid lipid nanoparticles intended for gene delivery: development, characterization and DNA binding efficiency of TCERG1 expression plasmid.

Science.gov (United States)

Fàbregas, Anna; Sánchez-Hernández, Noemí; Ticó, Josep Ramon; García-Montoya, Encarna; Pérez-Lozano, Pilar; Suñé-Negre, Josep M; Hernández-Munain, Cristina; Suñé, Carlos; Miñarro, Montserrat

2014-10-01

Solid lipid nanoparticles (SLNs) are being considered as a new approach for therapeutics for many known diseases. In addition to drug delivery, their use as non-viral vectors for gene delivery can be achieved by the inclusion of cationic lipids, which provide a positive surface potential that favours binding to the DNA backbone. This work is based on the idea that the optimization of the components is required as the first step in simplifying the qualitative and quantitative composition of SLNs as much as possible without affecting the essential properties that define SLNs as optimal non-viral vectors for gene delivery. We selected the best lipids and surfactants in terms of particle size and zeta potential and characterized the properties of the resulting nanoparticles using X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The SLNs had a particle size of approximately 120 nm and a positive surface charge of 42 mV. In addition, we analysed the main physicochemical characteristics of the bulk components of the nanoparticles using X-ray diffraction (XRD), differential scanning calorimetry (DSC) and mass spectrometry (MS). The suitability of the optimized SLNs for DNA binding was evaluated after the lyophilisation process using a carboxyl-terminal region of the TCERG1 gene, a human factor that has been implicated in several diseases. We show that the SLNs presented high efficiency in the binding of DNA, and importantly, they presented no toxicity when assayed in an in vivo system. Copyright © 2014 Elsevier B.V. All rights reserved.

Upper intestinal lipids regulate energy and glucose homeostasis.

Science.gov (United States)

Cheung, Grace W C; Kokorovic, Andrea; Lam, Tony K T

2009-09-01

Upon the entry of nutrients into the small intestine, nutrient sensing mechanisms are activated to allow the body to adapt appropriately to the incoming nutrients. To date, mounting evidence points to the existence of an upper intestinal lipid-induced gut-brain neuronal axis to regulate energy homeostasis. Moreover, a recent discovery has also revealed an upper intestinal lipid-induced gut-brain-liver neuronal axis involved in the regulation of glucose homeostasis. In this mini-review, we will focus on the mechanisms underlying the activation of these respective neuronal axes by upper intestinal lipids.

Impact of Estrogens and Estrogen Receptor Alpha (ESR1) in Brain Lipid Metabolism.

Science.gov (United States)

Morselli, Eugenia; de Souza Santos, Roberta; Gao, Su; Ávalos, Yenniffer; Criollo, Alfredo; Palmer, Biff F; Clegg, Deborah J

2018-03-06

Estrogens and their receptors play key roles in regulating body weight, energy expenditure, and metabolic homeostasis. It is known that lack of estrogens promotes increased food intake and induces the expansion of adipose tissues, for which much is known. An area of estrogenic research that has received less attention is the role of estrogens and their receptors in influencing intermediary lipid metabolism in organs such as the brain. In this review, we highlight the actions of estrogens and their receptors in regulating their impact on modulating fatty acid content, utilization, and oxidation through their direct impact on intracellular signaling cascades within the central nervous system.

Neuropeptide Y binding sites in rat brain identified with purified neuropeptide Y-I125

International Nuclear Information System (INIS)

Walker, M.W.; Miller, R.J.

1986-01-01

Neuropeptide Y (NPY) is a widely distributed neuronally localized peptide with 36 amino acids, 5 of which are tyrosines. The authors wished to investigate the properties of specific receptors for NPY. They therefore labeled the tyrosines with I125 using chloramine T and then purified the peptide using HPLC. A single mono-iodinated species of NPY which yielded > 85% specific binding in rat forebrain synaptosomes was selected as the ligand for all subsequent experiments. A time course of binding showed that equilibrium conditions were reached in 60 minutes at 21 0 C. Scatchard plots revealed a single class of binding sites with a Kd and a Bmax of 3 x 10-10 M and 28 pmol/mg, respectively. Competition binding with unlabeled NPY showed 50% displacement of bound ligand at 1 x 10-10 M NPY. Competition binding with rat pancreatic polypeptide (RPP), a homologous peptide possessing little NPY-like activity, showed 50% displacement of bound ligand at 2 x 10 -7 M RPP. No binding was observed on F-11 or PC12 neuronal cell lines, or on HSWP fibroblast cells. They conclude that NPY-I125 purified to homogeneity with HPLC is a highly selective ligand for NPY receptor sites. They are currently investigating such sites in brain, gut, and other tissues

Binding proteins for the regulatory subunit (RII-B) of brain cAMP-dependent protein kinase II: isolation and initial characterization of cDNA clones

International Nuclear Information System (INIS)

Bregman, D.B.; Hu, E.; Rubin, C.S.

1987-01-01

In mammalian brain several proteins bind RII-B with high affinity. An example is P75, which co-purifies with RII-B and also complexes Ca 2+ -calmodulin. Thus, RII-B binding proteins (RBPs) might play a role in integrating the Ca 2+ and cAMP signalling pathways in the CNS. In order to study the structure and function of these polypeptides they have isolated cloned cDNAs for RBPs by screening brain λgt11 expression libraries using a functional assay: the binding of 32 P-labeled RII to fusion proteins produced by recombinants expressing RII binding domains. Inserts from rat brain recombinant clones λ7B and λ10B both hybridize to a brain mRNA of 7000 nucleotides. Northern gel analyses indicate that the putative RBP mRNA is also expressed in lung, but not in several other tissues. The λ7B insert was subcloned into the expression plasmid pINIA. A 50 kDa high affinity RII-B binding polypeptide accumulated in E. coli transformed with pINIA-7B. Two RBP cDNAs (λ77, λ100A) have been retrieved from a bovine λgt 11 library using a monoclonal antibody directed against P75 and the binding assay respectively. On Southern blots the insert from λ100A hybridizes to the cDNA insert from clones λ77, suggesting that λ 77 cDNA might contain sequences coding for both an RII binding domain and a P75 epitope. The bovine λ100A insert also hybridizes with the rat λ7B clone indicating that an RII binding domain is conserved in the two species

Cultured bovine brain capillary endothelial cells (BBCEC) - a blood-brain barrier model for studying the binding and internalization of insulin and insulin-like growth factor 1

International Nuclear Information System (INIS)

Keller, B.T.; Borchardt, R.T.

1987-01-01

Cultured bovine brain capillary endothelial cells (BBCEC) have previously been reported by their laboratory as a working model for studying nutrient and drug transport and metabolism at the blood-brain barrier. In the present study, they have utilized this culture system to investigate the binding and internalization of [ 125 I]-labelled insulin (INS) and insulin-like growth factor 1(IGF-1) by BBCEC. After 2 hrs at 23 0 C, the specific binding of INS and IGF-1 was 1.6% and 13.6%, respectively. At 37 0 C, the maximum specific binding was 0.9% for INS and 5.8% for IGF-1. Using an acid-wash technique to assess peptide internalization, it was observed that, at 37 0 C, approximately 60% of the bound INS rapidly became resistant to acid treatment, a value which was constant over 2 hr. With IGF-1, a similar proportion of the bound material, 62%, became resistant by 30 min, but subsequently decreased to 45% by 2 hr. Scatchard analysis of competitive binding studies indicated the presence of two binding sites for each protein, having K/sub d/'s of 0.82 nM and 19.2 nM for INS and 0.39 nM and 3.66 nM for IGF-1. Little change in the amount of INS binding was observed over a four-day interval as the cultures became a confluent monolayer. The present report of binding and internalization of these proteins suggests that the BBCEC may utilize a receptor-mediated process to internalize and/or transport (transcytosis) INS and IGF-1 from the circulation

The Mammalian “Obesogen” Tributyltin Targets Hepatic Triglyceride Accumulation and the Transcriptional Regulation of Lipid Metabolism in the Liver and Brain of Zebrafish

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Lyssimachou, Angeliki; Santos, Joana G.; André, Ana; Soares, Joana; Lima, Daniela; Guimarães, Laura; Almeida, C. Marisa R.; Teixeira, Catarina; Castro, L. Filipe C.; Santos, Miguel M.

2015-01-01

Recent findings indicate that different Endocrine Disrupting Chemicals (EDCs) interfere with lipid metabolic pathways in mammals and promote fat accumulation, a previously unknown site of action for these compounds. The antifoulant and environmental pollutant tributyltin (TBT), which causes imposex in gastropod snails, induces an “obesogenic” phenotype in mammals, through the activation of the nuclear receptors retinoid X receptor (RXR) and peroxisome proliferator-activated receptor gamma (PPARγ). In teleosts, the effects of TBT on the lipid metabolism are poorly understood, particularly following exposure to low, environmental concentrations. In this context, the present work shows that exposure of zebrafish to 10 and 50 ng/L of TBT (as Sn) from pre-hatch to 9 months of age alters the body weight, condition factor, hepatosomatic index and hepatic triglycerides in a gender and dose related manner. Furthermore, TBT modulated the transcription of key lipid regulating factors and enzymes involved in adipogenesis, lipogenesis, glucocorticoid metabolism, growth and development in the brain and liver of exposed fish, revealing sexual dimorphic effects in the latter. Overall, the present study shows that the model mammalian obesogen TBT interferes with triglyceride accumulation and the transcriptional regulation of lipid metabolism in zebrafish and indentifies the brain lipogenic transcription profile of fish as a new target of this compound. PMID:26633012

A role for neuronal cAMP responsive-element binding (CREB)-1 in brain responses to calorie restriction

Science.gov (United States)

Fusco, Salvatore; Ripoli, Cristian; Podda, Maria Vittoria; Ranieri, Sofia Chiatamone; Leone, Lucia; Toietta, Gabriele; McBurney, Michael W.; Schütz, Günther; Riccio, Antonella; Grassi, Claudio; Galeotti, Tommaso; Pani, Giovambattista

2012-01-01

Calorie restriction delays brain senescence and prevents neurodegeneration, but critical regulators of these beneficial responses other than the NAD+-dependent histone deacetylase Sirtuin-1 (Sirt-1) are unknown. We report that effects of calorie restriction on neuronal plasticity, memory and social behavior are abolished in mice lacking cAMP responsive-element binding (CREB)-1 in the forebrain. Moreover, CREB deficiency drastically reduces the expression of Sirt-1 and the induction of genes relevant to neuronal metabolism and survival in the cortex and hippocampus of dietary-restricted animals. Biochemical studies reveal a complex interplay between CREB and Sirt-1: CREB directly regulates the transcription of the sirtuin in neuronal cells by binding to Sirt-1 chromatin; Sirt-1, in turn, is recruited by CREB to DNA and promotes CREB-dependent expression of target gene peroxisome proliferator-activated receptor-γ coactivator-1α and neuronal NO Synthase. Accordingly, expression of these CREB targets is markedly reduced in the brain of Sirt KO mice that are, like CREB-deficient mice, poorly responsive to calorie restriction. Thus, the above circuitry, modulated by nutrient availability, links energy metabolism with neurotrophin signaling, participates in brain adaptation to nutrient restriction, and is potentially relevant to accelerated brain aging by overnutrition and diabetes. PMID:22190495

FMRFamide: low affinity inhibition of opioid binding to rabbit brain membranes

International Nuclear Information System (INIS)

Zhu, X.Z.; Raffa, R.B.

1986-01-01

FMRFamide (Phe-Met-Arg-Phe-NH 2 ) was first isolated from the ganglia of molluscs by Price and Greenberg in 1977. The peptide was subsequently shown to have diverse actions on various types of molluscan and mammalian tissues. The presence of immunoreactive FMRFamide-like material (irFMRF) in multiple areas of rat brain, spinal cord, and gastrointestinal tract suggests that irFMRF may have a physiological role in mammals. Tang, Yang and Costa recently demonstrated that FMRFamide attenuates morphine antinociception in rats and postulated, based on this and several other lines of evidence, that irFMRF might be an endogenous opioid antagonist. In the present study, they tested the ability of FMRFamide to inhibit the binding of opioid receptor ligands to rabbit membrane preparations. FMRFamide inhibited the specific binding of both 3 [H]-dihydromorphine and 3 [H]-ethylketocyclazocine (IC 50 = 14 μM and 320 μM, respectively) in a dose-related manner, suggesting that FMRFamide may affect binding to at least two types of opioid receptors (mu and kappa). These data are consistent with the concept that irFMRF might act as an endogenous opioid antagonist. However, the low affinity of FMRFamide leaves open the possibility of another mechanism of opioid antagonism, such as neuromodulation

FMRFamide: low affinity inhibition of opioid binding to rabbit brain membranes

Energy Technology Data Exchange (ETDEWEB)

Zhu, X.Z.; Raffa, R.B.

1986-03-05

FMRFamide (Phe-Met-Arg-Phe-NH/sub 2/) was first isolated from the ganglia of molluscs by Price and Greenberg in 1977. The peptide was subsequently shown to have diverse actions on various types of molluscan and mammalian tissues. The presence of immunoreactive FMRFamide-like material (irFMRF) in multiple areas of rat brain, spinal cord, and gastrointestinal tract suggests that irFMRF may have a physiological role in mammals. Tang, Yang and Costa recently demonstrated that FMRFamide attenuates morphine antinociception in rats and postulated, based on this and several other lines of evidence, that irFMRF might be an endogenous opioid antagonist. In the present study, they tested the ability of FMRFamide to inhibit the binding of opioid receptor ligands to rabbit membrane preparations. FMRFamide inhibited the specific binding of both /sup 3/(H)-dihydromorphine and /sup 3/(H)-ethylketocyclazocine (IC/sub 50/ = 14 ..mu..M and 320 ..mu..M, respectively) in a dose-related manner, suggesting that FMRFamide may affect binding to at least two types of opioid receptors (mu and kappa). These data are consistent with the concept that irFMRF might act as an endogenous opioid antagonist. However, the low affinity of FMRFamide leaves open the possibility of another mechanism of opioid antagonism, such as neuromodulation.

Transferrin-tailored solid lipid nanoparticles as vectors for site-specific delivery of temozolomide to brain

Energy Technology Data Exchange (ETDEWEB)

Jain, Aviral, E-mail: draviraljain@gmail.com; Singhai, Priyanka; Gurnany, Ekta; Updhayay, Satish; Mody, Nishi [Adina Institute of Pharmaceutical Sciences, Pharmaceutics Research Laboratory, Department of Pharmaceutics (India)

2013-03-15

Blood-brain barrier restricts the uptake of many important hydrophilic drugs and limits their efficacy in the treatment of brain diseases because of the presence of tight junctions, high metabolic capacity, low pinocytic vesicular traffic, and efficient efflux mechanisms. In the present project, transferrin (Tf)-conjugated solid lipid nanoparticles (Tf-SLNs) were investigated for their ability to deliver temozolomide (TMZ) to the brain. SLNs were prepared by an ethanol injection method using hydrogenated soya phosphatidylcholine, triolein, cholesterol and distearoylphosphatidylethanolamine. Conjugation of SLNs with Tf was achieved by incubation of Tf with TMZ-loaded SLNs in the presence of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride in phosphate buffered saline (pH 7.4) as a cross linker. SLNs preparation were characterized for particle size, polydispersity index, zeta potential, surface morphology, percent drug entrapment efficiency, in vitro drug release, and hemolytic toxicity studies. In vitro cytotoxicity studies were performed on human cancer cell lines. The average size was found to be 221 {+-} 3.22 nm with entrapment efficiency of 69.83 {+-} 2.52 and 249 {+-} 2.61 nm with entrapment efficiency decreased to 64.21 {+-} 2.27 % for unconjugated SLNs and Tf-SLNs, respectively. Fluorescence studies revealed the enhanced uptake of Tf-SLNs in brain tissue compared with unconjugated SLNs.

Transferrin-tailored solid lipid nanoparticles as vectors for site-specific delivery of temozolomide to brain

Science.gov (United States)

Jain, Aviral; Singhai, Priyanka; Gurnany, Ekta; Updhayay, Satish; Mody, Nishi

2013-03-01

Blood-brain barrier restricts the uptake of many important hydrophilic drugs and limits their efficacy in the treatment of brain diseases because of the presence of tight junctions, high metabolic capacity, low pinocytic vesicular traffic, and efficient efflux mechanisms. In the present project, transferrin (Tf)-conjugated solid lipid nanoparticles (Tf-SLNs) were investigated for their ability to deliver temozolomide (TMZ) to the brain. SLNs were prepared by an ethanol injection method using hydrogenated soya phosphatidylcholine, triolein, cholesterol and distearoylphosphatidylethanolamine. Conjugation of SLNs with Tf was achieved by incubation of Tf with TMZ-loaded SLNs in the presence of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride in phosphate buffered saline (pH 7.4) as a cross linker. SLNs preparation were characterized for particle size, polydispersity index, zeta potential, surface morphology, percent drug entrapment efficiency, in vitro drug release, and hemolytic toxicity studies. In vitro cytotoxicity studies were performed on human cancer cell lines. The average size was found to be 221 ± 3.22 nm with entrapment efficiency of 69.83 ± 2.52 and 249 ± 2.61 nm with entrapment efficiency decreased to 64.21 ± 2.27 % for unconjugated SLNs and Tf-SLNs, respectively. Fluorescence studies revealed the enhanced uptake of Tf-SLNs in brain tissue compared with unconjugated SLNs.

Influences of the Structure of Lipids on Thermal Stability of Lipid Membranes

International Nuclear Information System (INIS)

Hai Nan-Nan; Zhou Xin; Li Ming

2015-01-01

The binding free energy (BFE) of lipid to lipid bilayer is a critical factor to determine the thermal or mechanical stability of the bilayer. Although the molecular structure of lipids has significant impacts on BFE of the lipid, there lacks a systematic study on this issue. In this paper we use coarse-grained molecular dynamics simulation to investigate this problem for several typical phospholipids. We find that both the tail length and tail unsaturation can significantly affect the BFE of lipids but in opposite way, namely, BFE decreases linearly with increasing length, but increases linearly with addition of unsaturated bonds. Inspired by the specific structure of cholesterol which is a crucial component of biomembrane, we also find that introduction of carbo-ring-like structures to the lipid tail or to the bilayer may greatly enhance the stability of the bilayer. Our simulation also shows that temperature can influence the bilayer stability and this effect can be significant when the bilayer undergoes phase transition. These results may be helpful to the design of liposome or other self-assembled lipid systems. (paper)

Brain delivery of valproic acid via intranasal administration of nanostructured lipid carriers: in vivo pharmacodynamic studies using rat electroshock model

Directory of Open Access Journals (Sweden)

Sharareh Eskandari

2011-02-01

Full Text Available Sharareh Eskandari1, Jaleh Varshosaz1, Mohsen Minaiyan2, Majid Tabbakhian11Department of Pharmaceutics, 2Department of Pharmacology, School of Pharmacy and Isfahan Pharmaceutical Sciences Research Center, Isfahan University of Medical Sciences, Isfahan, IranAbstract: The treatment of brain disorders is one of the greatest challenges in drug delivery because of a variety of main barriers in effective drug transport and maintaining therapeutic concentrations in the brain for a prolonged period. The objective of this study was delivery of valproic acid (VPA to the brain by intranasal route. For this purpose, nanostructured lipid carriers (NLCs were prepared by solvent diffusion method followed by ultrasonication and characterized for size, zeta potential, drug-loading percentage, and release. Six groups of rats each containing six animals received drug-loaded NLCs intraperitoneally (IP or intranasally. Brain responses were then examined by using maximal electroshock (MES. The hind limb tonic extension:flexion inhibition ratio was measured at 15-, 30-, 60-, 90-, and 120-minute intervals. The drug concentration was also measured in plasma and brain at the most protective point using gas chromatography method. The particle size of NLCs was 154 ± 16 nm with drug-loading percentage of 47% ± 0.8% and drug release of 75% ± 1.9% after 21 days. In vivo results showed that there was a significant difference between protective effects of NLCs of VPA and control group 15, 30, 60, and 90 minutes after treatment via intranasal route (P < 0.05. Similar protective effect was observed in rats treated with NLCs of VPA in intranasal route and positive control in IP route (P > 0.05. Results of drug determination in brain and plasma showed that brain:plasma concentration ratio was much higher after intranasal administration of NLCs of VPA than the positive control group (IP route. In conclusion, intranasal administration of NLCs of VPA provided a better protection

Systemic injection of kainic acid: Gliosis in olfactory and limbic brain regions quantified with [3H]PK 11195 binding autoradiography

International Nuclear Information System (INIS)

Altar, C.A.; Baudry, M.

1990-01-01

Neurodegenerative diseases may result from excessive stimulation of excitatory amino acid receptors by endogenous ligands. Because neuronal degeneration is associated with glial proliferation and hypertrophy, the degenerative changes throughout rat brain following the systemic administration of kainic acid (12 mg/kg) were mapped with quantitative autoradiography of [3H]PK 11195. This radioligand binds to a mitochondrial benzodiazepine binding site (MBBS) on microglia and astrocytes. Analysis of eight horizontal and four coronal brain levels revealed up to 16-fold increases in [3H]PK 11195 binding from 1 to 5 weeks but not 1 day after kainate injection. Increases in [3H]PK 11195 binding were predominantly in ventral limbic brain regions and olfactory projections to neocortical areas, with the olfactory cortex greater than subiculum/CA1 greater than anterior olfactory nucleus, medial thalamic nucleus, and piriform cortex greater than cingulate cortex and rostral hippocampus greater than dentate gyrus, septum, and amygdala greater than entorhinal cortex and temporal cortex. Little or no enhancement of [3H]PK 11195 binding was observed in numerous regions including the caudate-putamen, substantia nigra, nucleus accumbens, olfactory tubercle, cerebellum, thalamic nuclei, choroid plexus, medulla, parietal or occipital cortex, or pons. A 2-fold greater extent of neurodegeneration was obtained in ventral portions of the olfactory bulb, entorhinal cortex, temporal cortex, and dentate gyrus compared with the dorsal portions of these structures. The pattern of increase in [3H]PK 11195 binding closely matched the patterns of neuronal degeneration reported following parenteral kainate injection. These findings strengthen the notion that quantitative autoradiography of [3H]PK 11195 is a valuable tool to quantify the extent of neuronal degeneration

The Hepatitis C Virus-induced NLRP3 Inflammasome Activates the Sterol Regulatory Element-binding Protein (SREBP) and Regulates Lipid Metabolism.

Science.gov (United States)

McRae, Steven; Iqbal, Jawed; Sarkar-Dutta, Mehuli; Lane, Samantha; Nagaraj, Abhiram; Ali, Naushad; Waris, Gulam

2016-02-12

Hepatitis C virus (HCV) relies on host lipids and lipid droplets for replication and morphogenesis. The accumulation of lipid droplets in infected hepatocytes manifests as hepatosteatosis, a common pathology observed in chronic hepatitis C patients. One way by which HCV promotes the accumulation of intracellular lipids is through enhancing de novo lipogenesis by activating the sterol regulatory element-binding proteins (SREBPs). In general, activation of SREBPs occurs during cholesterol depletion. Interestingly, during HCV infection, the activation of SREBPs occurs under normal cholesterol levels, but the underlying mechanisms are still elusive. Our previous study has demonstrated the activation of the inflammasome complex in HCV-infected human hepatoma cells. In this study, we elucidate the potential link between chronic hepatitis C-associated inflammation and alteration of lipid homeostasis in infected cells. Our results reveal that the HCV-activated NLRP3 inflammasome is required for the up-regulation of lipogenic genes such as 3-hydroxy-3-methylglutaryl-coenzyme A synthase, fatty acid synthase, and stearoyl-CoA desaturase. Using pharmacological inhibitors and siRNA against the inflammasome components (NLRP3, apoptosis-associated speck-like protein containing a CARD, and caspase-1), we further show that the activation of the NLRP3 inflammasome plays a critical role in lipid droplet formation. NLRP3 inflammasome activation in HCV-infected cells enables caspase-1-mediated degradation of insulin-induced gene proteins. This subsequently leads to the transport of the SREBP cleavage-activating protein·SREBP complex from the endoplasmic reticulum to the Golgi, followed by proteolytic activation of SREBPs by S1P and S2P in the Golgi. Typically, inflammasome activation leads to viral clearance. Paradoxically, here we demonstrate how HCV exploits the NLRP3 inflammasome to activate SREBPs and host lipid metabolism, leading to liver disease pathogenesis associated with

Neuroimaging of Lipid Storage Disorders

Science.gov (United States)

Rieger, Deborah; Auerbach, Sarah; Robinson, Paul; Gropman, Andrea

2013-01-01

Lipid storage diseases, also known as the lipidoses, are a group of inherited metabolic disorders in which there is lipid accumulation in various cell types, including the central nervous system, because of the deficiency of a variety of enzymes. Over time, excessive storage can cause permanent cellular and tissue damage. The brain is particularly…

High-fat diet reduces local myostatin-1 paralog expression and alters skeletal muscle lipid content in rainbow trout, Oncorhynchus mykiss

Science.gov (United States)

Galt, Nicholas J.; Froehlich, Jacob Michael; Meyer, Ben M.; Barrows, Frederic T.; Biga, Peggy R.

2014-01-01

Muscle growth is an energetically demanding process that is reliant on intramuscular fatty acid depots in most fishes. The complex mechanisms regulating this growth and lipid metabolism are of great interest for human health and aquaculture applications. It is well established that the skeletal muscle chalone, myostatin, plays a role in lipid metabolism and adipogenesis in mammals; however, this function has not been fully assessed in fishes. We therefore examined the interaction between dietary lipid levels and myostatin expression in rainbow trout (Oncorhynchus mykiss). Five-weeks of high-fat (HFD; 25% lipid) dietary intake increased white muscle lipid content, and decreased circulating glucose levels and hepatosomatic index when compared to low-fat diet (LFD; 10% lipid) intake. In addition HFD intake reduced myostatin-1a and -1b expression in white muscle and myostatin-1b expression in brain tissue. Characterization of the myostatin-1a, -1b, and -2a promoters revealed putative binding sites for a subset of transcription factors associated with lipid metabolism. Taken together, these data suggest that HFD may regulate myostatin expression through cis-regulatory elements sensitive to increased lipid intake. Further, these findings provide a framework for future investigations of mechanisms describing the relationships between myostatin and lipid metabolism in fish. PMID:24264425

Interaction of red pepper (Capsicum annum, Tepin) polyphenols with Fe(II)-induced lipid peroxidation in brain and liver

International Nuclear Information System (INIS)

Oboh, G.; Rocha, J.B.T.

2006-03-01

Polyphenols exhibit a wide range of biological effects because of their antioxidant properties. Several types of polyphenols (phenolic acids, hydrolyzable tannins, and flavonoids) show anticarcinogenic and antimutagenic effects. Comparative studies were carried on the protective ability of free and bound polyphenol extracts of red Capsicum annuum Tepin (CAT) on brain and liver - In vitro. Free polyphenols of red Capsicum annuum Tepin (CAT) were extracted with 80% acetone, while the bound polyphenols were extracted with ethyl acetate from acid and alkaline hydrolysis of the pepper residue from free polyphenols extract. The phenol content, Fe (II) chelating ability, OH radical scavenging ability and protective ability of the extract against Fe (II)-induced lipid peroxidation in brain and liver was subsequently determined. The results of the study revealed that the free polyphenols (218.2mg/100g) content of the pepper were significantly higher than the bound polyphenols (42.5mg/100g). Furthermore, the free polyphenol extract had a significantly higher ( 2+ induced lipid peroxidation, and this is probably due to the higher Fe (II) chelating ability and OH radical scavenging ability of the free polyphenols from the pepper. (author)

Lysosomal degradation of membrane lipids.

Science.gov (United States)

Kolter, Thomas; Sandhoff, Konrad

2010-05-03

The constitutive degradation of membrane components takes place in the acidic compartments of a cell, the endosomes and lysosomes. Sites of lipid degradation are intralysosomal membranes that are formed in endosomes, where the lipid composition is adjusted for degradation. Cholesterol is sorted out of the inner membranes, their content in bis(monoacylglycero)phosphate increases, and, most likely, sphingomyelin is degraded to ceramide. Together with endosomal and lysosomal lipid-binding proteins, the Niemann-Pick disease, type C2-protein, the GM2-activator, and the saposins sap-A, -B, -C, and -D, a suitable membrane lipid composition is required for degradation of complex lipids by hydrolytic enzymes. Copyright 2009 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Amyloidogenesis abolished by proline substitutions but enhanced by lipid binding.

Directory of Open Access Journals (Sweden)

Ping Jiang

2009-04-01

Full Text Available The influence of lipid molecules on the aggregation of a highly amyloidogenic segment of human islet amyloid polypeptide, hIAPP20-29, and the corresponding sequence from rat has been studied by all-atom replica exchange molecular dynamics (REMD simulations with explicit solvent model. hIAPP20-29 fragments aggregate into partially ordered beta-sheet oligomers and then undergo large conformational reorganization and convert into parallel/antiparallel beta-sheet oligomers in mixed in-register and out-of-register patterns. The hydrophobic interaction between lipid tails and residues at positions 23-25 is found to stabilize the ordered beta-sheet structure, indicating a catalysis role of lipid molecules in hIAPP20-29 self-assembly. The rat IAPP variants with three proline residues maintain unstructured micelle-like oligomers, which is consistent with non-amyloidogenic behavior observed in experimental studies. Our study provides the atomic resolution descriptions of the catalytic function of lipid molecules on the aggregation of IAPP peptides.

Effects of hypoxia-ischemia and MK-801 treatment on the binding of a phencyclidine analogue in the developing rat brain

International Nuclear Information System (INIS)

Silverstein, F.S.; McDonald, J.W. III; Bommarito, M.; Johnston, M.V.

1990-01-01

The phencyclidine analogue [ 3 H](1-[2-thienyl]cyclohexyl)piperidine ( 3 H-TCP) binds to the ion channel associated with the N-methyl-D-aspartate receptor channel complex. In vitro autoradiography indicates that the distribution of 3 H-TCP binding in brain closely parallels that of [ 3 H]glutamate binding to the N-methyl-D-aspartate receptor. In nine 7-day-old rats, an acute focal hypoxic-ischemic insult produced by unilateral carotid artery ligation and subsequent exposure to 8% oxygen acutely reduced 3 H-TCP binding ipsilateral to the ligation by 30% in the CA1, by 27% in the CA3, by 26% in the dentate gyrus, and by 17% in the striatum compared with values from the contralateral hemisphere. In 10 littermates that received 1 mg/kg of the neuroprotective noncompetitive N-methyl-D-aspartate antagonist MK-801 immediately before hypoxic exposure, the regional distribution of 3 H-TCP binding in hypoxic-ischemic brain was relatively preserved and there were no interhemispheric asymmetries in 3 H-TCP binding densities. In addition, in three unoperated rats decapitated 24 hours after MK-801 treatment, 3 H-TCP binding was reduced by 15-35%; similar bilateral suppression of 3 H-TCP binding was detected in MK-801-treated ligates. Our data indicate that 3 H-TCP autoradiography can be used to assay the efficacy of neuroprotective agents in this experimental model of perinatal stroke

A subset of group A-like var genes encodes the malaria parasite ligands for binding to human brain endothelial cells

DEFF Research Database (Denmark)

Claessens, Antoine; Adams, Yvonne; Ghumra, Ashfaq

2012-01-01

Cerebral malaria is the most deadly manifestation of infection with Plasmodium falciparum. The pathology of cerebral malaria is characterized by the accumulation of infected erythrocytes (IEs) in the microvasculature of the brain caused by parasite adhesins on the surface of IEs binding to human...... receptors on microvascular endothelial cells. The parasite and host molecules involved in this interaction are unknown. We selected three P. falciparum strains (HB3, 3D7, and IT/FCR3) for binding to a human brain endothelial cell line (HBEC-5i). The whole transcriptome of isogenic pairs of selected.......029) but not by antibodies from controls with uncomplicated malaria (Mann-Whitney test, P = 0.58). This work describes a binding phenotype for virulence-associated group A P. falciparum erythrocyte membrane protein 1 variants and identifies targets for interventions to treat or prevent cerebral malaria....

Lipid Nanotechnology

Directory of Open Access Journals (Sweden)

Gijsje Koenderink

2013-02-01

Full Text Available Nanotechnology is a multidisciplinary field that covers a vast and diverse array of devices and machines derived from engineering, physics, materials science, chemistry and biology. These devices have found applications in biomedical sciences, such as targeted drug delivery, bio-imaging, sensing and diagnosis of pathologies at early stages. In these applications, nano-devices typically interface with the plasma membrane of cells. On the other hand, naturally occurring nanostructures in biology have been a source of inspiration for new nanotechnological designs and hybrid nanostructures made of biological and non-biological, organic and inorganic building blocks. Lipids, with their amphiphilicity, diversity of head and tail chemistry, and antifouling properties that block nonspecific binding to lipid-coated surfaces, provide a powerful toolbox for nanotechnology. This review discusses the progress in the emerging field of lipid nanotechnology.

Electrostatic control by lipids upon the membrane-bound (Na+ + K+)-ATPase.

Science.gov (United States)

Ahrens, M L

1981-04-06

In this paper, the membrane-bound (Na+ + K+)-ATPase from bovine brain is shown to be controlled by electrostatic alterations of the charged lipids surrounding the enzyme. The properties under investigation are the enzymatic activity, activation energy and the response of the enzymatic system to temperature. Arrhenius plots of the ATPase activity are biphasic with a break at temperature Ti. The temperature Ti, the activation energies at temperatures above and below Ti, and the enzymatic activity at any constant temperature have been shown to depend upon the concentrations of alkali and alkaline-earth metal ions in the solution. These electrolyte dependencies are ascribed to changes of electrostatic conditions at the lipids surrounding the ATPase. If the higher electrostatic screening ability of divalent ions is taken into account, the results in the presence of mono- and divalent ions become virtually the same. As a result of this work, it is concluded that electrostatic alterations are transmitted to the ATPase from the lipids of the membrane in which the enzyme is embedded. Inhibition and activation of the enzyme by mono-and divalent metal ions may thus be explained without any auxiliary hypothesis, particularly without postulating specific binding sites for the different ionic species at the protein. In addition, the specific lipid requirement of the ATPase may be understood better in the light of this interpretation.

Supported Lipid Bilayers with Phosphatidylethanolamine as the Major Component.

Science.gov (United States)

Sendecki, Anne M; Poyton, Matthew F; Baxter, Alexis J; Yang, Tinglu; Cremer, Paul S

2017-11-21

Phosphatidylethanolamine (PE) is notoriously difficult to incorporate into model membrane systems, such as fluid supported lipid bilayers (SLBs), at high concentrations because of its intrinsic negative curvature. Using fluorescence-based techniques, we demonstrate that having fewer sites of unsaturation in the lipid tails leads to high-quality SLBs because these lipids help to minimize the curvature. Moreover, shorter saturated chains can help maintain the membranes in the fluid phase. Using these two guidelines, we find that up to 70 mol % PE can be incorporated into SLBs at room temperature and up to 90 mol % PE can be incorporated at 37 °C. Curiously, conditions under which three-dimensional tubules project outward from the planar surface as well as conditions under which domain formation occurs can be found. We have employed these model membrane systems to explore the ability of Ni 2+ to bind to PE. It was found that this transition metal ion binds 1000-fold tighter to PE than to phosphatidylcholine lipids. In the future, this platform could be exploited to monitor the binding of other transition metal ions or the binding of antimicrobial peptides. It could also be employed to explore the physical properties of PE-containing membranes, such as phase domain behavior and intermolecular hydrogen bonding.

Sexually dimorphic development and binding characteristics of NMDA receptors in the brain of the platyfish

Science.gov (United States)

Flynn, K. M.; Schreibman, M. P.; Yablonsky-Alter, E.; Banerjee, S. P.

1999-01-01

This study investigated age- and gender-specific variations in properties of the glutamate N-methyl-d-aspartate receptor (NMDAR) in a freshwater teleost, the platyfish (Xiphophorus maculatus). Prior localization of the immunoreactive (ir)-R1 subunit of the NMDAR protein (R1) in cells of the nucleus olfactoretinalis (NOR), a primary gonadotropin-releasing hormone (GnRH)-containing brain nucleus in the platyfish, suggests that NMDAR, as in mammals, is involved in modulation of the platyfish brain-pituitary-gonad (BPG) axis. The current study shows that the number of cells in the NOR displaying ir-R1 is significantly increased in pubescent and mature female platyfish when compared to immature and senescent animals. In males, there is no significant change in ir-R1 expression in the NOR at any time in their lifespan. The affinity of the noncompetitive antagonist ((3)H)MK-801 for the NMDAR is significantly increased in pubescent females while maximum binding of ((3)H)MK-801 to the receptor reaches a significant maximum in mature females. In males, both MK-801 affinity and maximum binding remain unchanged throughout development. This is the first report of gender differences in the association of NMDA receptors with neuroendocrine brain areas during development. It is also the first report to suggest NMDA receptor involvement in the development of the BPG axis in a nonmammalian vertebrate. Copyright 1999 Academic Press.

Salt Bridge Formation between the I-BAR Domain and Lipids Increases Lipid Density and Membrane Curvature.

Science.gov (United States)

Takemura, Kazuhiro; Hanawa-Suetsugu, Kyoko; Suetsugu, Shiro; Kitao, Akio

2017-07-28

The BAR domain superfamily proteins sense or induce curvature in membranes. The inverse-BAR domain (I-BAR) is a BAR domain that forms a straight "zeppelin-shaped" dimer. The mechanisms by which IRSp53 I-BAR binds to and deforms a lipid membrane are investigated here by all-atom molecular dynamics simulation (MD), binding energy analysis, and the effects of mutation experiments on filopodia on HeLa cells. I-BAR adopts a curved structure when crystallized, but adopts a flatter shape in MD. The binding of I-BAR to membrane was stabilized by ~30 salt bridges, consistent with experiments showing that point mutations of the interface residues have little effect on the binding affinity whereas multiple mutations have considerable effect. Salt bridge formation increases the local density of lipids and deforms the membrane into a concave shape. In addition, the point mutations that break key intra-molecular salt bridges within I-BAR reduce the binding affinity; this was confirmed by expressing these mutants in HeLa cells and observing their effects. The results indicate that the stiffness of I-BAR is important for membrane deformation, although I-BAR does not act as a completely rigid template.

Effects of vanadium on different adenosinetriphosphatases and binding of 3H-labeled ouabain and calcium-45 to rat brain synaptosomes

International Nuclear Information System (INIS)

Mishra, S.K.; Osborn, R.L.; Desaiah, D.

1981-01-01

The effect of vanadium chloride on rat brain synaptosomal adenosinetriphosphatase (ATPase) activities was determined in vitro and in rats treated at 1 mg/kg and 10 mg/kg for 10 d. Additional experiments were conducted to determine the effect of vanadium chloride on binding of [ 3 H]ouabain and 45 Ca to rat brain synaptosomes. Na + + K + - and Ca 2+ -ATPase activities were inhibited significantly in a concentration-dependent manner by V in vitro. Mg 2+ -ATPase inhibition was neither dose-dependent nor significant except at 10 -5 M. Na + + K + -ATPase inhibition by V was more pronounced than that of other ATPases studied. Vanadium inhibited [ 3 H]ouabain binding to synaptosomes by 90% at 10 -3 M; the inhibition was concentration-dependent. Binding of 45 Ca was inhibited 50% at 10 -4 M; but concentration-dependent inhibition was not evident. Rats treated with vanadium chloride neither became myotonic nor showed any changes in ATPase activities or binding of [ 3 H]ouabain and 45 Ca to brain synaptosomes. Line-weaver-Burke plots of the in vitro inhibition of Na + + K + -ATPase and [ 3 H]ouabain binding revealed that (1) Na + + K + -ATPase activation by ATP was inhibited by V with an increase in K/sub m/ and a decrease in V/sub max/; (2) Na + activation was inhibited noncompetitively by V, as evidenced by a decrease in V/sub max/ and no change in K/sub m/; (3) K + activation was inhibited by V with a decrease in both V/sub max/ and K/sub m/; (4) noncompetitive inhibition of Mg 2+ -ATPase by V was observed; and (5) the kinetic behavior of [ 3 H]ouabain binding inhibition by V with respect to ATP and Na + activation was mixed and noncompetitive, respectively

Fine print in isotope effects: the glucose anomeric equilibrium and binding of glucose to human brain hexokinase

International Nuclear Information System (INIS)

Lewis, B.E; Schramm, V.L.

2002-01-01

Binding isotope effects are a sensitive measure of changes in molecular vibrational character that occur during ligand-receptor binding. In this study, we have measured isotope effects on the binding of glucose to human brain hexokinase using the ultrafiltration method, with the following results: 0.991±0.001, 0.908±0.003, 1.010±0.001, 0.974±0.002, 1.022±0.002 for [ 14 C]-glucose mixed with [1- 3 H]-, [2- 3 H]-, [3- 3 H]-, [5- 3 H]-, [6,6- 3 H]-glucose, respectively. Comparing the observed data with isotope effects on the anomeric equilibrium in glucose reported previously proves the existence of binding isotope effects in this system. Preliminary computational results are presented to explain the observed binding isotope effects in terms of hydrogen bond patterns and molecular crowding found in the binary complex of sugar and enzyme. (author)

Brain-specific fatty acid-binding protein is elevated in serum of patients with dementia-related diseases

NARCIS (Netherlands)

Teunissen, C.E.; Veerhuis, R.; de Vente, J.; Verhey, F.R.J.; Vreeling, F.; van Boxtel, M.P.J.; Glatz, J.F.C.; Pelsers, M.A.L.

2011-01-01

Background: There is a need for biomarkers in accessible matrices, such as blood, for the diagnosis of neurodegenerative diseases. The aim of this study was to measure the serum levels of brain-type fatty acid-binding protein (FABP) and heart-type FABP in patients with dementia-involving diseases.

Lipid dependence of ABC transporter localization and function

NARCIS (Netherlands)

Klappe, Karin; Hummel, Ina; Hoekstra, Dick; Kok, Jan Willem

2009-01-01

Lipid rafts have been implicated in many cellular functions, including protein and lipid transport and signal transduction. ATP-binding cassette (ABC) transporters have also been localized in these membrane domains. In this review the evidence for this specific localization will be evaluated and

Effects of trihexyphenidyl and L-dopa on brain muscarinic cholinergic receptor binding measured by positron emission tomography

Energy Technology Data Exchange (ETDEWEB)

Shinotoh, H; Asahina, M; Hirayama, K [Dept. of Neurology, School of Medicine, Chiba Univ., Chiba (Japan); Inoue, O; Suhara, T; Tateno, Y [Division of Clinical Research, National Inst. of Radiological Sciences, Chiba (Japan)

1994-01-01

The effects of pharmacological intervention on brain muscarinic cholinergic receptor (mAChR) binding were assessed in seven patients with Parkinson's disease by positron emission tomography and carbon-11 labelled N-methyl-4-piperidyl benzilate ([[sup 11]C]NMPB). [[sup 11]C]NMPB was injected twice, approximately 2 hours apart, in each patient, to assess the effect of single doses of 4 mg of trihexyphenidyl (n=5) or 400 mg of L-dopa with 57 mg of benserazide (n=2) on the binding parameter of mAChRs (K[sub 3]). There was a mean 28% inhibition of K[sub 3] values in the brain in the presence of trihexyphenidyl, which was assumed to reflect mAChR occupancy. No significant change in K[sub 3] was observed in the presence of L-dopa. This study demonstrates the feasibility of measuring mAChR occupancy by an anticholinergic medication with PET.

Preparation of biologically active 32P-labeled human relaxin. Displaceable binding to rat uterus, cervix, and brain

International Nuclear Information System (INIS)

Osheroff, P.L.; Ling, V.T.; Vandlen, R.L.; Cronin, M.J.; Lofgren, J.A.

1990-01-01

Relaxin is a member of the insulin family of polypeptide hormones and is known to exert its biological effects on various parts of the mammalian reproductive system. Biologically active human relaxin has been chemically synthesized based on the nucleotide sequence obtained from an ovarian cDNA clone. In the present study synthetic human relaxin was radiolabled by phosphorylation with cAMP-dependent protein kinase and [gamma-32P]ATP to a specific activity of 5000 Ci/mmol. The phosphorylated relaxin was purified on cation exchange high performance liquid chromatography and was shown to co-migrate with relaxin on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Mass spectrometry revealed a single phosphorylated site on the B chain of relaxin. The 32P-relaxin was able to bind to a goat anti-relaxin antibody, and this binding could be displaced by unlabeled relaxin in a concentration-dependent manner. A comparison of the concentration responses of cellular cAMP production stimulated by relaxin and phosphorylated relaxin in a primary human uterine cell line showed that phosphorylation did not affect the in vitro biological efficacy of relaxin. This made it suitable for in situ autoradiographic localization of relaxin binding sites in rat uterine, cervical, and brain tissue sections. Displacement of the binding of 100 pM 32P-relaxin by 100, 10, and 3 nM unlabeled relaxin, but not by 100 nM insulin, insulin-like growth factor-I, and an insulin-like growth factor-I analog, demonstrated the high affinity and specificity of such binding. We conclude that 32P-labeled human relaxin is biologically and immunologically active and that this novel probe binds reversibly and with high affinity to classical (e.g. uterus) and unpredicted (e.g. brain) tissues

Solid lipid nanoparticles carrying chemotherapeutic drug across the blood-brain barrier through insulin receptor-mediated pathway.

Science.gov (United States)

Kuo, Yung-Chih; Shih-Huang, Chun-Yuan

2013-09-01

Carmustine (BCNU)-loaded solid lipid nanoparticles (SLNs) were grafted with 83-14 monoclonal antibody (MAb) (83-14 MAb/BCNU-SLNs) and applied to the brain-targeting delivery. Human brain-microvascular endothelial cells (HBMECs) incubated with 83-14 MAb/BCNU-SLNs were stained to demonstrate the interaction between the nanocarriers and expressed insulin receptors (IRs). The results revealed that the particle size of 83-14 MAb/BCNU-SLNs decreased with an increasing weight percentage of Dynasan 114 (DYN). Storage at 4 °C for 6 weeks slightly deformed the colloidal morphology. In addition, poloxamer 407 on 83-14 MAb/BCNU-SLNs induced cytotoxicity to RAW264.7 cells and inhibited phagocytosis by RAW264.7 cells. An increase in the weight percentage of DYN from 0% to 67% slightly reduced the viability of RAW264.7 cells and promoted phagocytosis. Moreover, the transport ability of 83-14 MAb/BCNU-SLNs across the blood-brain barrier (BBB) in vitro enhanced with an increasing weight percentage of Tween 80. 83-14 MAb on MAb/BCNU-SLNs stimulated endocytosis by HBMECs via IRs and enhanced the permeability of BCNU across the BBB. 83-14 MAb/BCNU-SLNs can be a promising antitumor drug delivery system for transporting BCNU to the brain.

White Matter Lipids as a Ketogenic Fuel Supply in Aging Female Brain: Implications for Alzheimer's Disease.

Science.gov (United States)

Klosinski, Lauren P; Yao, Jia; Yin, Fei; Fonteh, Alfred N; Harrington, Michael G; Christensen, Trace A; Trushina, Eugenia; Brinton, Roberta Diaz

2015-12-01

White matter degeneration is a pathological hallmark of neurodegenerative diseases including Alzheimer's. Age remains the greatest risk factor for Alzheimer's and the prevalence of age-related late onset Alzheimer's is greatest in females. We investigated mechanisms underlying white matter degeneration in an animal model consistent with the sex at greatest Alzheimer's risk. Results of these analyses demonstrated decline in mitochondrial respiration, increased mitochondrial hydrogen peroxide production and cytosolic-phospholipase-A2 sphingomyelinase pathway activation during female brain aging. Electron microscopic and lipidomic analyses confirmed myelin degeneration. An increase in fatty acids and mitochondrial fatty acid metabolism machinery was coincident with a rise in brain ketone bodies and decline in plasma ketone bodies. This mechanistic pathway and its chronologically phased activation, links mitochondrial dysfunction early in aging with later age development of white matter degeneration. The catabolism of myelin lipids to generate ketone bodies can be viewed as a systems level adaptive response to address brain fuel and energy demand. Elucidation of the initiating factors and the mechanistic pathway leading to white matter catabolism in the aging female brain provides potential therapeutic targets to prevent and treat demyelinating diseases such as Alzheimer's and multiple sclerosis. Targeting stages of disease and associated mechanisms will be critical.

White Matter Lipids as a Ketogenic Fuel Supply in Aging Female Brain: Implications for Alzheimer's Disease

Directory of Open Access Journals (Sweden)

Lauren P. Klosinski

2015-12-01

Full Text Available White matter degeneration is a pathological hallmark of neurodegenerative diseases including Alzheimer's. Age remains the greatest risk factor for Alzheimer's and the prevalence of age-related late onset Alzheimer's is greatest in females. We investigated mechanisms underlying white matter degeneration in an animal model consistent with the sex at greatest Alzheimer's risk. Results of these analyses demonstrated decline in mitochondrial respiration, increased mitochondrial hydrogen peroxide production and cytosolic-phospholipase-A2 sphingomyelinase pathway activation during female brain aging. Electron microscopic and lipidomic analyses confirmed myelin degeneration. An increase in fatty acids and mitochondrial fatty acid metabolism machinery was coincident with a rise in brain ketone bodies and decline in plasma ketone bodies. This mechanistic pathway and its chronologically phased activation, links mitochondrial dysfunction early in aging with later age development of white matter degeneration. The catabolism of myelin lipids to generate ketone bodies can be viewed as a systems level adaptive response to address brain fuel and energy demand. Elucidation of the initiating factors and the mechanistic pathway leading to white matter catabolism in the aging female brain provides potential therapeutic targets to prevent and treat demyelinating diseases such as Alzheimer's and multiple sclerosis. Targeting stages of disease and associated mechanisms will be critical.

Long-term music training tunes how the brain temporally binds signals from multiple senses

OpenAIRE

Lee, HweeLing; Noppeney, Uta

2011-01-01

Practicing a musical instrument is a rich multisensory experience involving the integration of visual, auditory, and tactile inputs with motor responses. This combined psychophysics–fMRI study used the musician's brain to investigate how sensory-motor experience molds temporal binding of auditory and visual signals. Behaviorally, musicians exhibited a narrower temporal integration window than nonmusicians for music but not for speech. At the neural level, musicians showed increased audiovisua...

Radioautographic localization of somatostatin-14 and somatostatin-28 binding sites in the rat brain

International Nuclear Information System (INIS)

Leroux, P.; Pelletier, G.

1984-01-01

Somatostatin-14 (S14) and its precursor, somatostatin-28 (S28), are widely distributed throughout the rat brain, suggesting that they could act as neurotransmitter or neuromodulator in the central nervous system. The present study was undertaken to study the localization of S14 and S28 receptors in the rat brain determined by ''in vitro'' radioautography. The study performed on slide mounted frozen brain section with iodinated S14 and S28 analogs revealed an identical distribution of binding sites for the two forms of somatostatin. A good correlation could be observed between receptor distribution and immunohistologically localized neuropeptides except for striatum and hypothalamus. However, receptors were not detectable in the hypothalamus and were found in low concentration in the caudate-putamen nucleus, two regions containing high amounts of S28 and S14, suggesting a high occupancy of receptors in these areas by endogenous peptides or an inverse correlation between receptor and peptide concentrations

[Modification of retinal photoreceptor membranes and Ca ion binding].

Science.gov (United States)

Korchagin, V P; Berman, A L; Shukoliukov, S A; Rychkova, M P; Etingof, R N

1978-10-01

Calcium binding by modified photoreceptor membranes of cattle retina has been studied. Ca2+-binding the membranes significantly changes after C-phospholipase treatment, displaying the initial growth (less than 65% of lipid phosphorus removed) with subsequent decrease (more than 65% of phosphorus removed). Liposomes of the photoreceptor membranes lipids were found to bind more calcium than do the native photoreceptor membranes. Proteolytic enzymes (papaine, pronase) splitting some rhodopsin fragments do not affect the ability of the membrane to bind Ca2+. The increase of light-induced Ca-binding is observed only after the outer segments preincubation under conditions providing for rhodopsin phosphorylation. This effect was observed also after the splitting of the rhodopsin fragment by papaine. It is concluded that calcium binding in the photoreceptor membranes is mainly due to the phosphate groups of phospholipids.

Nanodiscs for immobilization of lipid bilayers and membrane receptors: kinetic analysis of cholera toxin binding to a glycolipid receptor

DEFF Research Database (Denmark)

Borch, Jonas; Torta, Federico; Sligar, Stephen G

2008-01-01

nanodiscs and their incorporated membrane receptors can be attached to surface plasmon resonance sensorchips and used to measure the kinetics of the interaction between soluble molecules and membrane receptors inserted in the bilayer of nanodiscs. Cholera toxin and its glycolipid receptor G(M1) constitute...... a system that can be considered a paradigm for interactions of soluble proteins with membrane receptors. In this work, we have investigated different technologies for capturing nanodiscs containing the glycolipid receptor G(M1) in lipid bilayers, enabling measurements of binding of its soluble interaction...

A REVIEW ON CORRELATION BETWEEN LIPID PROFILE AND DEPRESSION

Directory of Open Access Journals (Sweden)

Lalitha Devi Dhulipala

2016-07-01

Full Text Available Epidemiological and clinical intervention data indicate that low levels of circulating lipids and cholesterol are the risk factors for depressive symptoms. Olie et al 2011 (1 showed an association of low cholesterol and self-harm in their study. In the present scenario, depression and anxiety disorders have high prevalence rates and are frequently related. Understanding the subject and concepts/mechanisms related to neurobiological basis for these disorders is very important and the available techniques or methods are ineffective. Lipids generally play an important role in neural function in the brain. The composition of lipid of the brain influences perception, mood and behaviour. Lipids are responsible to regulate the membrane's function which acts as a barrier between the intracellular and extracellular spaces. It is found that membrane lipids determine the local behaviour and characterisation and function of proteins within the membrane. It is found from the literature that lipids can influence both exo-and endocytic processes and work within the membrane as second messengers. This paper discusses some important case studies related to the correlation between lipid profile and the depression.

Receptor binding of somatostatin-14 and somatostatin-28 in rat brain: differential modulation by nucleotides and ions.

Science.gov (United States)

Srikant, C B; Dahan, A; Craig, C

1990-02-04

The tissue-selective binding of the two principal bioactive forms of somatostatin, somatostatin-14 (SS-14) and somatostatin-28 (SS-28), their ability to modulate cAMP-dependent and -independent regulation of post-receptor events to different degrees and the documentation of specific labelling of SS receptor subtypes with SS-28 but not SS-14 in discrete regions of rat brain suggest the existence of distinct SS-14 and SS-28 binding sites. Receptor binding of SS-14 ligands has been shown to be modulated by nucleotides and ions, but the effect of these agents on SS-28 binding has not been studied. In the present study we investigated the effects of adenine and guanine nucleotides as well as monovalent and divalent cations on rat brain SS receptors quantitated with radioiodinated analogs of SS-14 ([125I-Tyr11]SS14, referred to in this paper as SS-14) and SS-28 ([Leu8, D-Trp22, 125I-Tyr25] SS-28, referred to as LTT* SS-28) in order to determine if distinct receptor sites for SS-14 and SS-28 could be distinguished on the basis of their modulation by nucleotides and ions. GTP as well as ATP exerted a dose-dependent inhibition (over a concentration range of 10(-7)-10(-3) M) of the binding of the two radioligands. The nucleotide inhibition of binding resulted in a decrease the Bmax of the SS receptors, the binding affinity remaining unaltered. GTP (10(-4) M) decreased the Bmax of LTT* SS-28 binding sites to a greater extent than ATP (145 +/- 10 and 228 +/- 16 respectively, compared to control value of 320 +/- 20 pmol mg-1). Under identical conditions GTP was less effective than ATP in reducing the number of T* SS-14 binding sites (Bmax = 227 +/- 8 and 182 +/- 15, respectively, compared to 340 +/- 15 pmol mg-1 in the absence of nucleotides). Monovalent cations inhibited the binding of both radioligands, Li+ and Na+ inhibited the binding of T* SS-14 to a greater extent than K+. The effect of divalent cations on the other hand was varied. At low concentration (2 mM) Mg2+, Ba2

[11C]Doxepin binding to histamine H1 receptors in living human brain in association with attentive waking and circadian rhythm

Directory of Open Access Journals (Sweden)

Kazuhiko eYanai

2012-06-01

Full Text Available Molecular imaging in neuroscience is a new research field that enables visualization of the impact of molecular events on brain structure and function in humans. While magnetic resonance-based imaging techniques can provide complex information at the level of system, positron emission tomography (PET enables determination of the distribution and density of receptor and enzyme in the human brain. Previous studies using [11C]raclopride revealed that the release of neuronal dopamine was increased in human brain by psychostimulants or reward stimuli. Following on from these previous studies, we examined whether the levels of neuronal release of histamine might change [11C]doxepin binding to the H1 receptors under the influence of physiological stimuli. The purpose of the present study was to evaluate the test-retest reliability of quantitative measurement of [11C]doxepin binding between morning and afternoon and between resting and attentive waking conditions in healthy human subjects. There was a trend for a decrease in [11C]doxepin binding during attentive calculation tasks compared with that in resting conditions, but the difference (approximately 10% was not significant. In contrast, the binding potential of [11C]doxepin in the anterior cingulate gyrus was significantly higher in the morning than that in the afternoon (approximately 19%, suggesting that higher histamine release in the morning would decrease the [11C]doxepin binding in the afternoon. This study suggests that non-invasive measurement of neuronal histamine release is feasible in humans by PET ligand-activation study, although the development of a tracer with better signal-to-noise properties is needed.

NADPH oxidase and lipid raft-associated redox signaling are required for PCB153-induced upregulation of cell adhesion molecules in human brain endothelial cells

International Nuclear Information System (INIS)

Eum, Sung Yong; Andras, Ibolya; Hennig, Bernhard; Toborek, Michal

2009-01-01

Exposure to persistent organic pollutants, such as polychlorinated biphenyls (PCBs), can lead to chronic inflammation and the development of vascular diseases. Because cell adhesion molecules (CAMs) of the cerebrovascular endothelium regulate infiltration of inflammatory cells into the brain, we have explored the molecular mechanisms by which ortho-substituted polychlorinated biphenyls (PCBs), such as PCB153, can upregulate CAMs in brain endothelial cells. Exposure to PCB153 increased expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), as well as elevated adhesion of leukocytes to brain endothelial cells. These effects were impeded by inhibitors of EGFR, JAKs, or Src activity. In addition, pharmacological inhibition of NADPH oxidase or disruption of lipid rafts by cholesterol depleting agents blocked PCB153-induced phosphorylation of JAK and Src kinases and upregulation of CAMs. In contrast, silencing of caveolin-1 by siRNA interference did not affect upregulation of ICAM-1 and VCAM-1 in brain endothelial cells stimulated by PCB153. Results of the present study indicate that lipid raft-dependent NADPH oxidase/JAK/EGFR signaling mechanisms regulate the expression of CAMs in brain endothelial cells and adhesion of leukocytes to endothelial monolayers. Due to its role in leukocyte infiltration, induction of CAMs may contribute to PCB-induced cerebrovascular disorders and neurotoxic effects in the CNS.

[123I]FP-CIT binding in rat brain after acute and sub-chronic administration of dopaminergic medication

International Nuclear Information System (INIS)

Lavalaye, J.; Knol, R.J.J.; Bruin, K. de; Reneman, L.; Booij, J.; Janssen, A.G.M.

2000-01-01

The recently developed radioligand [ 123 I]FP-CIT is suitable for clinical single-photon emission tomography (SPET) imaging of the dopamine (DA) transporter in vivo. To date it has remained unclear whether dopaminergic medication influences the striatal [ 123 I]FP-CIT binding. The purpose of this study was to investigate the influence of this medication on [ 123 I]FP-CIT binding in the brain. We used an animal model in which we administered dopaminomimetics, antipsychotics and an antidepressant. In vivo [ 123 I]FP-CIT binding to the DA and serotonin transporters was evaluated after sub-chronic and acute administration of the drugs. The administered medication induced small changes in striatal [ 123 I]FP-CIT binding which were not statistically significant. As expected, the DA reuptake blocker GBR 12,909 induced a significant decrease in [ 123 I]FP-CIT binding. [ 123 I]FP-CIT binding in the serotonin-rich hypothalamus was decreased only after acute administration of fluvoxamine. The results of this study suggest that dopaminergic medication will not affect the results of DA transporter SPET imaging with [ 123 I]FP-CIT. (orig.)

A Soluble Fluorescent Binding Assay Reveals PIP2 Antagonism of TREK-1 Channels

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Cerrone Cabanos

2017-08-01

Full Text Available Lipid regulation of ion channels by low-abundance signaling lipids phosphatidylinositol 4,5-bisphosphate (PIP2 and phosphatidic acid (PA has emerged as a central cellular mechanism for controlling ion channels and the excitability of nerves. A lack of robust assays suitable for facile detection of a lipid bound to a channel has hampered the probing of the lipid binding sites and measuring the pharmacology of putative lipid agonists for ion channels. Here, we show a fluorescent PIP2 competition assay for detergent-purified potassium channels, including TWIK-1-related K+-channel (TREK-1. Anionic lipids PA and phosphatidylglycerol (PG bind dose dependently (9.1 and 96 μM, respectively and agonize the channel. Our assay shows PIP2 binds with high affinity (0.87 μM but surprisingly can directly antagonize TREK-1 in liposomes. We propose a model for TREK-1 lipid regulation where PIP2 can compete with PA and PG agonism based on the affinity of the lipid for a site within the channel.

Autoradiographic localization of glucocorticosteriod binding sites in rat brain after in vivo injection of [3H]RU 28362

International Nuclear Information System (INIS)

Sarrieau, Alain; Dussaillant, Monique; Rostene, William

1988-01-01

The autoradiographic distribution of glucocorticosteriod binding sites in the brain of adrenalectomized rats was studied following in vivo injection of a potent synthetic glucocorticosteriod agonist [ 3 H]RU 28362. Analysis of the autoradiograms revealed a specific and dense labelling in the pyramidal cell layer of the Ammon's horn and in the granular cell layer of the dentate gyrus of the hippocampus. In the hypothalmus, the labelling was particularly high in the paraventricular nucleus (site of CRF synthesis), the arcuate, periventricular and the supraoptic nuclei as well as in the median eminence. Autoradiograms also revealed the presence of[ 3 H]RU 28362 binding sites in several brain regions including the amygdala, the pineal gland, the entorhinal cortex, the interpeduncular, interfascicular and dorsal raphe nuclei, the central grey and the substantia nigra suggesting possible effects of glucocorticosteriods in these structures (author)

Probing protein-lipid interactions by FRET between membrane fluorophores

Science.gov (United States)

Trusova, Valeriya M.; Gorbenko, Galyna P.; Deligeorgiev, Todor; Gadjev, Nikolai

2016-09-01

Förster resonance energy transfer (FRET) is a powerful fluorescence technique that has found numerous applications in medicine and biology. One area where FRET proved to be especially informative involves the intermolecular interactions in biological membranes. The present study was focused on developing and verifying a Monte-Carlo approach to analyzing the results of FRET between the membrane-bound fluorophores. This approach was employed to quantify FRET from benzanthrone dye ABM to squaraine dye SQ-1 in the model protein-lipid system containing a polycationic globular protein lysozyme and negatively charged lipid vesicles composed of phosphatidylcholine and phosphatidylglycerol. It was found that acceptor redistribution between the lipid bilayer and protein binding sites resulted in the decrease of FRET efficiency. Quantification of this effect in terms of the proposed methodology yielded both structural and binding parameters of lysozyme-lipid complexes.

Preliminary studies of 99mTc-PQQ-NMDAR binding and effect of specificity binding by mannitol

International Nuclear Information System (INIS)

Xingqin Zhou; Yanyan Kong; Guoxian Cao; Jiankang Zhang

2013-01-01

Pyrroloquinoline quinone (PQQ) is a powerful neuroprotectant that specifically binds to brain NMDA receptors and inhibits excitotoxicity. Imaging this binding reaction in the brain remains a long sought goal in this field of study, and one of the primary challenges remaining is enabling soluble labeled PQQ to pass the blood-brain barrier (BBB). Previously, our group successfully labeled PQQ with Technetium-99m ( 99m Tc), a metastable nuclear isomer used in radioactive isotope medical tests. In this work, we determined the specific binding of 99m Tc-PQQ and NMDAR by radioligand receptor assay. Ebselen (EB) and MK-801 both effectively inhibited 99m Tc-PQQ binding. We then investigated methods of opening the BBB using mannitol to enable entry to the brain by 99m Tc-PQQ. Our results showed that 7.5 mL/kg of 20 % mannitol effectively opened the BBB and 20 min was the optimum treatment time. Competition studies showed that mannitol did not affect the specific binding between 99m Tc-PQQ and NMDA receptors. Using this method, the amount of 99m Tc-PQQ uptake and retention was increased most significantly in the hippocampus and cortex, and re-opening the BBB did not affect binding. Together, our results demonstrate that the use of mannitol to open the BBB may contribute significantly to improving image quality by increasing the uptake amount of a water-soluble agent in brain. (author)

Lead-Binding Proteins: A Review

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Harvey C. Gonick

2011-01-01

Full Text Available Lead-binding proteins are a series of low molecular weight proteins, analogous to metallothionein, which segregate lead in a nontoxic form in several organs (kidney, brain, lung, liver, erythrocyte. Whether the lead-binding proteins in every organ are identical or different remains to be determined. In the erythrocyte, delta-aminolevulinic acid dehydratase (ALAD isoforms have commanded the greatest attention as proteins and enzymes that are both inhibitable and inducible by lead. ALAD-2, although it binds lead to a greater degree than ALAD-1, appears to bind lead in a less toxic form. What may be of greater significance is that a low molecular weight lead-binding protein, approximately 10 kDa, appears in the erythrocyte once blood lead exceeds 39 μg/dL and eventually surpasses the lead-binding capacity of ALAD. In brain and kidney of environmentally exposed humans and animals, a cytoplasmic lead-binding protein has been identified as thymosin β4, a 5 kDa protein. In kidney, but not brain, another lead-binding protein has been identified as acyl-CoA binding protein, a 9 kDa protein. Each of these proteins, when coincubated with liver ALAD and titrated with lead, diminishes the inhibition of ALAD by lead, verifying their ability to segregate lead in a nontoxic form.

Study of lipid profile and parieto-temporal lipid peroxidation in AlCl3 mediated neurotoxicity. modulatory effect of fenugreek seeds

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Belaïd-Nouira Yosra

2012-01-01

Full Text Available Abstract Background Peroxidation of lipid (LPO membrane and cholesterol metabolism have been involved in the physiopathology of many diseases of aging brain. Therefore, this prospective animal study was carried firstly to find out the correlation between LPO in posterior brain and plasmatic cholesterol along with lipoprotein levels after chronic intoxication by aluminium chloride (AlCl3. Chronic aluminum-induced neurotoxicity has been in fact related to enhanced brain lipid peroxidation together with hypercholesterolemia and hypertriglyceridemia, despite its controversial etiological role in neurodegenerative diseases. Secondly an evaluation of the effectiveness of fenugreek seeds in alleviating the engendered toxicity through these biochemical parameters was made. Results Oral administration of AlCl3 to rats during 5 months (500 mg/kg bw i.g for one month then 1600 ppm via the drinking water enhanced the levels of LPO in posterior brain, liver and plasma together with lactate dehydrogenase (LDH activities, total cholesterol (TC, triglycerides (TG and LDL-C (Low Density Lipoproteins levels. All these parameters were decreased following fenugreek seeds supplementation either as fenugreek seed powder (FSP or fenugreek seed extract (FSE. A notable significant correlation was observed between LPObrain and LDL-C on one hand and LDHliver on the other hand. This latter was found to correlate positively with TC, TG and LDL-C. Furthermore, high significant correlations were observed between LDHbrain and TC, TG, LDL-C, LPObrain as well as LDHliver. Conclusion Aluminium-induced LPO in brain could arise from alteration of lipid metabolism particularly altered lipoprotein metabolism rather than a direct effect of cholesterol oxidation. Fenugreek seeds could play an anti-peroxidative role in brain which may be attributed in part to its modulatory effect on plasmatic lipid metabolism.

Preliminary assessment of extrastriatal dopamine d-2 receptor binding in the rodent and nonhuman primate brains using the high affinity radioligand, {sup 18}F-fallypride

Energy Technology Data Exchange (ETDEWEB)

Mukherjee, Jogeshwar E-mail: jogeshwar-mukherjee@ketthealth.com; Yang, Z.-Y.; Brown, Terry; Lew, Robert; Wernick, Miles; Ouyang Xiaohu; Yasillo, Nicholas; Chen, C.-T.; Mintzer, Robert; Cooper, Malcolm

1999-07-01

We have identified the value of {sup 18}F-fallypride {l_brace}(S)-N-[(1-allyl-2-pyrrolidinyl)methyl]-5-(3-[{sup 18}F]fluoropropyl)-2,3-dim= ethoxybenzamide{r_brace}, as a dopamine D-2 receptor radiotracer for the study of striatal and extrastriatal receptors. Fallypride exhibits high affinities for D-2 and D-3 subtypes and low affinity for D-4 ({sup 3}H-spiperone IC{sub 50}s: D-2=0.05 nM [rat striata], D-3=0.30 nM [SF9 cell lines, rat recombinant], and D-4=240 nM [CHO cell lines, human recombinant]). Biodistribution in the rat brain showed localization of {sup 18}F-fallypride in striata and extrastriatal regions such as the frontal cortex, parietal cortex, amygdala, hippocampus, thalamus, and hypothalamus. In vitro autoradiographic studies in sagittal slices of the rat brain showed localization of {sup 18}F-fallypride in striatal and several extrastriatal regions, including the medulla. Positron emission tomography (PET) experiments with {sup 18}F-fallypride in male rhesus monkeys were carried out in a PET VI scanner. In several PET experiments, apart from the specific binding seen in the striatum, specific binding of {sup 18}F-fallypride was also identified in extracellular regions (in a lower brain slice, possibly the thalamus). Specific binding in the extrastriata was, however, significantly lower compared with that observed in the striata of the monkeys (extrastriata/cerebellum = 2, striata/cerebellum = 10). Postmortem analysis of the monkey brain revealed significant {sup 18}F-fallypride binding in the striata, whereas binding was also observed in extrastriatal regions such as the thalamus, cortical areas, and brain stem.

Serotonin 2A receptor agonist binding in the human brain with [¹¹C]Cimbi-36

DEFF Research Database (Denmark)

Ettrup, Anders; Svarer, Claus; McMahon, Brenda

2016-01-01

INTRODUCTION: [(11)C]Cimbi-36 is a recently developed serotonin 2A (5-HT2A) receptor agonist positron emission tomography (PET) radioligand that has been successfully applied for human neuroimaging. Here, we investigate the test-retest variability of cerebral [(11)C]Cimbi-36 PET and compare [(11)C...... test-retest variability in [(11)C]Cimbi-36 binding measures, and another eight were scanned after a bolus plus constant infusion with [(18)F]altanserin. Regional differences in the brain distribution of [(11)C]Cimbi-36 and [(18)F]altanserin were assessed with a correlation of regional binding measures...... and with voxel-based analysis. RESULTS: Test-retest variability of [(11)C]Cimbi-36 non-displaceable binding potential (BPND) was consistently correlation between regional...

Can Xanthophyll-Membrane Interactions Explain Their Selective Presence in the Retina and Brain?

Science.gov (United States)

Widomska, Justyna; Zareba, Mariusz; Subczynski, Witold Karol

2016-01-01

Epidemiological studies demonstrate that a high dietary intake of carotenoids may offer protection against age-related macular degeneration, cancer and cardiovascular and neurodegenerative diseases. Humans cannot synthesize carotenoids and depend on their dietary intake. Major carotenoids that have been found in human plasma can be divided into two groups, carotenes (nonpolar molecules, such as β-carotene, α-carotene or lycopene) and xanthophylls (polar carotenoids that include an oxygen atom in their structure, such as lutein, zeaxanthin and β-cryptoxanthin). Only two dietary carotenoids, namely lutein and zeaxanthin (macular xanthophylls), are selectively accumulated in the human retina. A third carotenoid, meso-zeaxanthin, is formed directly in the human retina from lutein. Additionally, xanthophylls account for about 70% of total carotenoids in all brain regions. Some specific properties of these polar carotenoids must explain why they, among other available carotenoids, were selected during evolution to protect the retina and brain. It is also likely that the selective uptake and deposition of macular xanthophylls in the retina and brain are enhanced by specific xanthophyll-binding proteins. We hypothesize that the high membrane solubility and preferential transmembrane orientation of macular xanthophylls distinguish them from other dietary carotenoids, enhance their chemical and physical stability in retina and brain membranes and maximize their protective action in these organs. Most importantly, xanthophylls are selectively concentrated in the most vulnerable regions of lipid bilayer membranes enriched in polyunsaturated lipids. This localization is ideal if macular xanthophylls are to act as lipid-soluble antioxidants, which is the most accepted mechanism through which lutein and zeaxanthin protect neural tissue against degenerative diseases. PMID:27030822

Can Xanthophyll-Membrane Interactions Explain Their Selective Presence in the Retina and Brain?

Directory of Open Access Journals (Sweden)

Justyna Widomska

2016-01-01

Full Text Available Epidemiological studies demonstrate that a high dietary intake of carotenoids may offer protection against age-related macular degeneration, cancer and cardiovascular and neurodegenerative diseases. Humans cannot synthesize carotenoids and depend on their dietary intake. Major carotenoids that have been found in human plasma can be divided into two groups, carotenes (nonpolar molecules, such as β-carotene, α-carotene or lycopene and xanthophylls (polar carotenoids that include an oxygen atom in their structure, such as lutein, zeaxanthin and β-cryptoxanthin. Only two dietary carotenoids, namely lutein and zeaxanthin (macular xanthophylls, are selectively accumulated in the human retina. A third carotenoid, meso-zeaxanthin, is formed directly in the human retina from lutein. Additionally, xanthophylls account for about 70% of total carotenoids in all brain regions. Some specific properties of these polar carotenoids must explain why they, among other available carotenoids, were selected during evolution to protect the retina and brain. It is also likely that the selective uptake and deposition of macular xanthophylls in the retina and brain are enhanced by specific xanthophyll-binding proteins. We hypothesize that the high membrane solubility and preferential transmembrane orientation of macular xanthophylls distinguish them from other dietary carotenoids, enhance their chemical and physical stability in retina and brain membranes and maximize their protective action in these organs. Most importantly, xanthophylls are selectively concentrated in the most vulnerable regions of lipid bilayer membranes enriched in polyunsaturated lipids. This localization is ideal if macular xanthophylls are to act as lipid-soluble antioxidants, which is the most accepted mechanism through which lutein and zeaxanthin protect neural tissue against degenerative diseases.

Omega-3 Fatty Acids Could Alleviate the Risks of Traumatic Brain Injury – A Mini Review

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Parvathy R. Kumar

2014-04-01

Full Text Available Traumatic brain injury (TBI is an acquired brain trauma that occurs when any sudden trauma/injury causes damage to the brain. TBI is characterized by tissue damage and imbalance in the cerebral blood flow and metabolism. It has been established through laboratory experiments that the dietary supplementation of omega-3 fatty acids (FAs could reduce the oxidative stress developed in brain due to TBI. The inclusion of omega-3 FA in diet could normalize the levels of brain-derived neurotrophic factor (BDNF, and thus, it could restore the survival of neuronal cells. BDNF improves the synaptic transmission by regulating synapsin 1 and cyclic adenosine monophosphate (cAMP response element binding protein. The brain tissue analysis of TBI models supplemented with omega-3 polyunsaturated fatty acids (PUFAs showed significantly reduced lipid peroxidation, nucleic acid and protein oxidation, thereby promoting neuronal and glial cell survival. Thus, omega-3 FA intake could be considered as a therapeutic option to reduce the secondary neuronal damages initiated by TBI.

Cationic solid-lipid nanoparticles can efficiently bind and transfect plasmid DNA

NARCIS (Netherlands)

Olbrich, C; Bakowsky, U; Muller, RH; Kneuer, C

2001-01-01

The suitability of cationically modified solid-lipid nanoparticles (SLN) as a novel transfection agent was investigated. SLN were produced by hot homogenisation using either Compritol ATO 888 or paraffin as matrix lipid, a mixture of Tween 80 and Span 85 as tenside and either EQ1

Interaction of polycationic antibiotics with Pseudomonas aeruginosa lipopolysaccharide and lipid A studied by using dansyl-polymyxin.

Science.gov (United States)

Moore, R A; Bates, N C; Hancock, R E

1986-01-01

A fluorescent derivative of polymyxin B (dansyl-polymyxin) was used to study the interaction of polycations with lipopolysaccharide (LPS) and lipid A from Pseudomonas aeruginosa. Dansyl-polymyxin became bound to LPS and lipid A sites, including Mg2+-binding sites, resulting in a 20-fold enhancement of fluorescence. A Hill plot of the binding data showed that the binding of dansyl-polymyxin to LPS was cooperative (n = 1.98) and of high affinity (S0.5 = 0.38 microM). The maximal binding capacity of LPS was approximately four molecules of dansyl-polymyxin per mol of LPS. The dansyl-polymyxin interaction with lipid A displayed similar kinetics (n = 2.26; S0.5 = 0.38 microM), and the maximal binding capacity was approximately 2 mol of dansyl-polymyxin per mol of lipid A. A variety of polycationic compounds, including gentamicin, streptomycin, and polymyxin B, as well as Mg2+, were able to displace dansyl-polymyxin bound to LPS or to lipid A. Marked differences both in terms of the degree of displacement and in terms of the amount of competing polycation required to displace a given amount of dansyl-polymyxin were observed. Addition of excess polymyxin B resulted in displacement of all of the dansyl-polymyxin, demonstrating that only polymyxin-binding sites were being probed. Our data demonstrate that polymyxin B binds to multiple sites on LPS, including sites which bind aminoglycoside antibiotics and other polycationic compounds. PMID:3013085

Effects of chronic delta-9-tetrahydrocannabinol (THC) administration on neurotransmitter concentrations and receptor binding in the rat brain

International Nuclear Information System (INIS)

Ali, S.F.; Newport, G.D.; Scallet, A.C.; Gee, K.W.; Paule, M.G.; Brown, R.M.; Slikker, W. Jr.

1989-01-01

THC is the major psychoactive constituent of marijuana and is also known as an hallucinogenic compound. Numerous reports have shown that large doses of THC produce significant alterations in various neurotransmitter systems. The present study was designed to determine whether chronic exposure to THC produces significant alterations in selected neurotransmitter systems (dopamine, serotonin, acetylcholine, GABAergic, benzodiazepine, and opiate) in the rat brain. In Experiment 1, male Sprague-Dawley rats were gavaged with vehicle, 10 or 20 mg THC/kg body weight daily, 5 days/week for 90 days. Animals were killed either 24 hours or two months after the last dose. Brains were dissected into different regions for neurochemical analyses. Two months after the cessation of chronic administration, there was a significant decrease in GABA receptor binding in the hippocampus of animals in the high dose group. However, no other significant changes were found in neurotransmitter receptor binding characteristics in the hippocampus or in neurotransmitter concentrations in the caudate nucleus, hypothalamus or septum after chronic THC administration. In an attempt to replicate the GABA receptor binding changes and also to determine the [35S]TBPS binding in hippocampus, we designed Experiment 2. In this experiment, we dosed the animals by gavage with 0, 5, 10 or 20 mg THC/kg daily, 5 days/week or with 20 mg THC/kg Monday through Thursday and 60 mg/kg on Friday for 90 days. Results from this experiment failed to replicate the dose-dependent effect of THC on GABA receptor binding in hippocampus. Modulation of [35S]TBPS binding by GABA or 3 alpha-OH-DHP or inhibition by cold TBPS in frontal cortex did not show any significant dose-related effects

Transcriptional Regulation of T-Cell Lipid Metabolism: Implications for Plasma Membrane Lipid Rafts and T-Cell Function

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George A. Robinson

2017-11-01

Full Text Available It is well established that cholesterol and glycosphingolipids are enriched in the plasma membrane (PM and form signaling platforms called lipid rafts, essential for T-cell activation and function. Moreover, changes in PM lipid composition affect the biophysical properties of lipid rafts and have a role in defining functional T-cell phenotypes. Here, we review the role of transcriptional regulators of lipid metabolism including liver X receptors α/β, peroxisome proliferator-activated receptor γ, estrogen receptors α/β (ERα/β, and sterol regulatory element-binding proteins in T-cells. These receptors lie at the interface between lipid metabolism and immune cell function and are endogenously activated by lipids and/or hormones. Importantly, they regulate cellular cholesterol, fatty acid, glycosphingolipid, and phospholipid levels but are also known to modulate a broad spectrum of immune responses. The current evidence supporting a role for lipid metabolism pathways in controlling immune cell activation by influencing PM lipid raft composition in health and disease, and the potential for targeting lipid biosynthesis pathways to control unwanted T-cell activation in autoimmunity is reviewed.

Light-enhanced inhibition of ouabain binding to digitalis receptor in rat brain and guinea pig heart by the food dye erythrosine

International Nuclear Information System (INIS)

Hnatowich, M.; LaBella, F.S.

1982-01-01

Erythrosine (ERY) (FD and C red no. 3) inhibited specific binding of [ 3 H]ouabain to rat brain homogenates with an IC50 of 23 mM in the dark and 1 mM in ordinary fluorescent light. Competition studies demonstrated the presence of two components, only one of which was affected by light. Lineweaver-Burk analysis indicated that ERY preferentially antagonizes [ 3 H]ouabain binding at a high-affinity site in the light, whereas in the dark the dye inhibits binding in a manner qualitatively similar to inhibition by ouabain. Light enhancement of ERY potency occurred only when dye and tissue were present together in the incubation medium, pointing to participation of transient molecular species. However, neither superoxide dismutase nor catalase altered the effects of ERY in the light or dark, suggesting the absence of oxygen free radicals. In contrast to brain, membranes from guinea pig heart showed only one binding site for [ 3 H]ouabain, and antagonism by ERY at this site was markedly enhanced by light. Structural differences between classes of ouabain binding regions probably accounts for the discrimination exhibited by ERY in the presence of light and oxygen. Our findings also caution that metabolic transformation of this common food dye, light decomposition, or photoreaction with foodstuff may yield more toxic derivatives

Identification of binding sites for an insulin-like growth factor (IGF-I) in the median eminence of the rat brain by quantitative autoradiography

International Nuclear Information System (INIS)

Bohannon, N.J.; Figlewicz, D.P.; Corp, E.S.; Wilcox, B.J.; Porte, D. Jr.; Baskin, D.G.

1986-01-01

The microanatomical location of IGF-I binding in the rat brain was determined by in vitro autoradiography with slide-mounted sections of frozen brain. Sections incubated in 0.1 nM [ 125 I]-iodo-IGF-I produced a dense grain concentration in regions of the autoradiographic image corresponding to the external palisade zone of the median eminence; other hypothalamic regions were not so heavily labeled. This reaction was significantly reduced in the presence of 100 nM IGF-I. Measurement of binding by computer digital image analysis of autoradiographic images showed that specific binding for IGF-I in the median eminence was 41.3 +/- 8 X 10(-3) fmol/mm2 (mean +/- SEM); nonspecific binding was 11.9 +/- 1.8 X 10(-3) fmol/mm2. In contrast, specific binding to other hypothalamic regions was uniformly lower. In a separate experiment, 1000 nM unlabeled insulin was added. Without insulin, specific binding was 23 +/- 0.9 X 10(-3) fmol/mm2; nonspecific binding was 8 +/- 0.5 X 10(-3) fmol/mm2. In the presence of 1000 nM unlabeled insulin, specific binding for [ 125 I]-iodo-IGF-I was 23 +/- 1 X 10(-3) fmol/mm2. The results suggest that a high concentration of receptors for an IGF-I-like molecule is present in the median eminence

Binding of the GTPase Sar1 to a Lipid Membrane Monolayer: Insertion and Orientation Studied by Infrared Reflection–Absorption Spectroscopy

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Christian Schwieger

2017-11-01

Full Text Available Membrane-interacting proteins are polyphilic polymers that engage in dynamic protein–protein and protein–lipid interactions while undergoing changes in conformation, orientation and binding interfaces. Predicting the sites of interactions between such polypeptides and phospholipid membranes is still a challenge. One example is the small eukaryotic GTPase Sar1, which functions in phospholipid bilayer remodeling and vesicle formation as part of the multimeric coat protein complex (COPII. The membrane interaction of Sar1 is strongly dependent on its N-terminal 23 amino acids. By monolayer adsorption experiments and infrared reflection-absorption spectroscopy (IRRAS, we elucidate the role of lipids in inducing the amphipathicity of this N-terminal stretch, which inserts into the monolayer as an amphipathic helix (AH. The AH inserting angle is determined and is consistent with the philicities and spatial distribution of the amino acid monomers. Using an advanced method of IRRAS data evaluation, the orientation of Sar1 with respect to the lipid layer prior to the recruitment of further COPII proteins is determined. The result indicates that only a slight reorientation of the membrane-bound Sar1 is needed to allow coat assembly. The time-course of the IRRAS analysis corroborates a role of slow GTP hydrolysis in Sar1 desorption from the membrane.

How membrane lipids control the 3D structure and function of receptors

OpenAIRE

Jacques Fantini; Francisco J. Barrantes

2018-01-01

The cohabitation of lipids and proteins in the plasma membrane of mammalian cells is controlled by specific biochemical and biophysical rules. Lipids may be either constitutively tightly bound to cell-surface receptors (non-annular lipids) or less tightly attached to the external surface of the protein (annular lipids). The latter are exchangeable with surrounding bulk membrane lipids on a faster time scale than that of non-annular lipids. Not only do non-annular lipids bind to membrane prote...

Iodine-123-labeled pH shift brain-imaging agents

International Nuclear Information System (INIS)

Blau, M.; Kung, H.F.

1985-01-01

HIPDM is an 123 I-labeled agent with a distribution in brain reflecting regional perfusion. This compound is neutral and lipid soluble at blood pH and freely crosses the blood-brain barrier. At the lower pH in brain, it picks up a hydrogen ion and becomes positively charged. In this form the molecule is not lipid soluble and it is trapped in brain

Echinococcus granulosus fatty acid binding proteins subcellular localization.

Science.gov (United States)

Alvite, Gabriela; Esteves, Adriana

2016-05-01

Two fatty acid binding proteins, EgFABP1 and EgFABP2, were isolated from the parasitic platyhelminth Echinococcus granulosus. These proteins bind fatty acids and have particular relevance in flatworms since de novo fatty acids synthesis is absent. Therefore platyhelminthes depend on the capture and intracellular distribution of host's lipids and fatty acid binding proteins could participate in lipid distribution. To elucidate EgFABP's roles, we investigated their intracellular distribution in the larval stage by a proteomic approach. Our results demonstrated the presence of EgFABP1 isoforms in cytosolic, nuclear, mitochondrial and microsomal fractions, suggesting that these molecules could be involved in several cellular processes. Copyright © 2016 Elsevier Inc. All rights reserved.

The influence of L-DOPA on the accumulation of lipid peroxidation products in some brain structures affected by radiation

International Nuclear Information System (INIS)

Babaev, R.A.; Kocharli, R.Kh.; Akhmedova, G.Sh.; Gasanova, A.A.; Babaev, Kh.F.

1990-01-01

A study was made of the effect of L-DOPA on the dynamics of changes in lipid peroxidation products (LPP) and the content of various types of SH-groups in certain brain structures (oblongata, cerebellum, visual and sensorimotor cortex) and their synaptosomal fractions upon irradiation. The preadministration of L-DOPA to irradiated rats inhibited LPP accumulation, prevented the decrease in the content of various types of thiols and thus exerted an antioxidant effect

Difference in brain distributions of carbon 11-labeled 4-hydroxy-2(1H)-quinolones as PET radioligands for the glycine-binding site of the NMDA ion channel

Energy Technology Data Exchange (ETDEWEB)

Fuchigami, Takeshi [Graduate School of Pharmaceutical Sciences, Kyushu University, Higashi-ku, Fukuoka 812-8582 (Japan); Photon Medical Research Center, Hamamatsu University School of Medicine, Hamamatsu 431-3192 (Japan); Haradahira, Terushi [Molecular Imaging Center, National Institute of Radiological Sciences, Inage-ku, Chiba 263-8555 (Japan)], E-mail: terushi@niu.ac.jp; Fujimoto, Noriko [Graduate School of Pharmaceutical Sciences, Kyushu University, Higashi-ku, Fukuoka 812-8582 (Japan); Okauchi, Takashi; Maeda, Jun; Suzuki, Kazutoshi; Suhara, Tetsuya [Molecular Imaging Center, National Institute of Radiological Sciences, Inage-ku, Chiba 263-8555 (Japan); Yamamoto, Fumihiko; Sasaki, Shigeki; Mukai, Takahiro [Graduate School of Pharmaceutical Sciences, Kyushu University, Higashi-ku, Fukuoka 812-8582 (Japan); Yamaguchi, Hiroshi [Molecular Imaging Frontier Research Center, Hamamatsu University School of Medicine, Hamamatsu 431-3192 (Japan); Ogawa, Mikako [Photon Medical Research Center, Hamamatsu University School of Medicine, Hamamatsu 431-3192 (Japan); Magata, Yasuhiro [Photon Medical Research Center, Hamamatsu University School of Medicine, Hamamatsu 431-3192 (Japan); Molecular Imaging Frontier Research Center, Hamamatsu University School of Medicine, Hamamatsu 431-3192 (Japan); Maeda, Minoru [Graduate School of Pharmaceutical Sciences, Kyushu University, Higashi-ku, Fukuoka 812-8582 (Japan)

2008-02-15

High-affinity iodine- and ethyl-C-5 substituted analogs of 4-hydroxy-3-(3-[{sup 11}C]methoxyphenyl)-2(1H)-quinolone ([{sup 11}C]4HQ) were synthesized as new positron emission tomography radioligands for the glycine-binding sites of the N-methyl-D-aspartate (NMDA) ion channel. Although both radioligands showed high in vitro specific binding to rat brain slices, their binding characteristics were quite different from each other. 5-Ethyl-[{sup 11}C]4HQ (5Et-[{sup 11}C]4HQ) showed higher in vitro binding in the forebrain regions than in the cerebellum, bindings that were strongly inhibited by both glycine-site agonists and antagonists. In contrast, 5-iodo-[{sup 11}C]4HQ (5I-[{sup 11}C]4HQ) showed a homogeneous in vitro binding throughout the brain, which was inhibited by antagonists but not by agonists. This difference in in vitro binding between 5Et-[{sup 11}C]4HQ and 5I-[{sup 11}C]4HQ was quite similar to that previously observed between [{sup 11}C]L-703,717 and [{sup 11}C]4HQ, both glycine-site antagonists. In vivo brain uptakes of these {sup 11}C-labeled 4-hydroxyquinolones were examined in mice. Initial brain uptakes of 5Et- and 5I-[{sup 11}C]4HQ at 1 min after intravenous injections were comparable to that of [{sup 11}C]4HQ, but they were 1.3-2.1 times higher than that of [{sup 11}C]L-703,717. The treatment with an anticoagulant, warfarin, only slightly increased the initial uptakes of [{sup 11}C]4HQ and 5Et-[{sup 11}C]4HQ in contrast to [{sup 11}C]L-703,717. The in vivo regional brain distributions were slightly different between the two radioligands. Pretreatment with nonradioactive ligand (2 mg/kg) slightly inhibited the binding of 5Et-[{sup 11}C]4HQ (16-36% inhibition) but not that of 5I-[{sup 11}C]4HQ. In this study, it was found that a small structural change in [{sup 11}C]4HQ resulted in a major change in binding characteristics and distributions, suggesting the existence of two binding sites for [{sup 11}C]4-hydroxyquinolones on the NMDA ion channel

Effect of different commercial fat sources on brain, liver and blood lipid profiles of rats in growth phase

OpenAIRE

Angelis-Pereira, Michel Cardoso de; Barcelos, Maria de Fátima Píccolo; Pereira, Juciane de Abreu Ribeiro; Pereira, Rafaela Corrêa; Souza, Raimundo Vicente de

2017-01-01

Abstract Purpose: To investigate the fatty acid content of different fat sources and evaluate the effect of them on plasma and hepatic lipids and on the fatty acid profile of the brain tissue of Wistar rats. Methods: Thirty male albino Wistar rats received for 59 days, the following diets: diet added of margarine with low content of polyunsaturated fatty acids (PUFA); diet added of margarine with high content of PUFA; diet added of butter; diet added of hydrogenated vegetable fat; diet ad...

Specific in vivo binding in the rat brain of [18F]RP 62203: A selective 5-HT2A receptor radioligand for positron emission tomography

International Nuclear Information System (INIS)

Besret, Laurent; Dauphin, Francois; Huard, Cecile; Lasne, Marie-Claire; Vivet, Richard; Mickala, Patrick; Barbelivien, Alexandra; Baron, Jean-Claude

1996-01-01

In vivo pharmacokinetic and brain binding characteristics of [ 18 F]RP 62203, a selective high-affinity serotonergic 5-HT 2A receptor antagonist, were assessed in the rat following intravenous injection of trace amount of the radioligand. The radioactive distribution profile observed in the brain 60 min after injection was characterized by greater than fourfold higher uptake in neocortex as compared to cerebellum (0.38 ± 0.07% injected dose/g, % ID/g and 0.08 ± 0.01 ID/g, respectively), consistent with in vivo specific binding to the 5-HT 2A receptor. Furthermore, specific [ 18 F]RP 62203 binding significantly correlated with the reported in vitro distribution of 5-HT 2A receptors, but not with known concentration profiles of dopaminergic D 2 or adrenergic α 1 receptors. Finally, detectable specific binding was abolished by pretreatment with large doses of ritanserin, a selective 5-HT 2A antagonist, which resulted in uniform uptakes across cortical, striatal and cerebellar tissues. Thus, [ 18 F]RP 62203 appears to be a promising selective tool to visualize and quantify 5-HT 2A brain receptors in vivo with positron emission tomography

Light-enhanced inhibition of ouabain binding to digitalis receptor in rat brain and guinea pig heart by the food dye erythrosine

International Nuclear Information System (INIS)

Hnatowich, M.; LaBella, F.S.

1982-01-01

Erythrosine (ERY) (FD and C red no. 3) inhibited specific binding of [ 3 H]ouabain to rat brain homogenates with an IC50 of 23 microM in the dark and 1 microM in ordinary fluorescent light. Competition studies demonstrated the presence of two components, only one of which was affected by light. Lineweaver-Burk analysis indicated that ERY preferentially antagonizes [ 3 H]ouabain binding at a high-affinity site in the light, whereas in the dark the dye inhibits binding in a manner qualitatively similar to inhibition by ouabain. Light enhancement of ERY potency occurred only when dye and tissue were present together in the incubation medium, pointing to participation of transient molecular species. However, neither superoxide dismutase nor catalase altered the effects of ERY in the light or dark, suggesting the absence of oxygen free radicals. When oxygen levels were raised, there was enhancement of inhibition by ERY at a high-affinity receptor accompanied by disappearance of [ 3 H]ouabain binding at one of lower affinity. In contrast to brain, membranes from guinea pig heart showed only one binding site for [ 3 H]ouabain, and antagonism by ERY at this site was markedly enhanced by light. Structural differences between classes of ouabain binding regions probably accounts for the discrimination exhibited by ERY in the presence of light and oxygen. Our findings also caution that metabolic transformation of this common food dye, light decomposition, or photoreaction with foodstuff may yield more toxic derivatives

Evaluation of the in vitro differential protein adsorption patterns of didanosine-loaded nanostructured lipid carriers (NLCs) for potential targeting to the brain.

Science.gov (United States)

Kasongo, Kasongo Wa; Jansch, Mirko; Müller, Rainer H; Walker, Roderick B

2011-09-01

The preferential in vitro adsorption of apolipoprotein E (Apo E) onto the surface of colloidal drug carriers may be used as a strategy to evaluate the in vivo potential for such systems to transport drugs to the brain. The aim of this research was to investigate the in vitro protein adsorption patterns of didanosine-loaded nanostructured lipid carriers (DDI-NLCs), using two-dimensional polyacrylamide gel electrophoresis (2-D PAGE), in order to establish the potential for NLCs to deliver DDI to the brain. NLC formulations were manufactured using high-pressure homogenization using a lipid matrix consisting of a mixture of Precirol(®) ATO 5 and Transcutol(®) HP. The 2-D PAGE analysis revealed that NLCs in formulations stabilized using Solutol(®) HS 15 alone or with a ternary surfactant system consisting of Solutol(®) HS 15, Tween(®) 80, and Lutrol(®) F68, preferentially adsorbed proteins, such as Apo E. Particles stabilized with Tween(®) 80 and Lutrol(®) F68 did not adsorb Apo E in these studies, which could be related to the relatively large particle size and hence small surface area observed for these NLCs. These findings have revealed that DDI-loaded NLCs may have the potential to deliver DDI to the brain in vivo and, in addition, to Tween(®) 80, which has already been shown to have the ability to facilitate the targeting of colloidal drug delivery systems to the brain. Solutol(®) HS 15-stabilized nanoparticles may also achieve a similar purpose.

New aspects of phloem-mediated long-distance lipid signaling in plants

Directory of Open Access Journals (Sweden)

Urs Florian Benning

2012-03-01

Full Text Available Plants are sessile and cannot move to appropriate hiding places or feeding grounds to escape adverse conditions. As a consequence, they evolved mechanisms to detect changes in their environment, communicate these to different organs, and adjust development accordingly. These adaptations include two long-distance transport systems which are essential in plants: the xylem and the phloem. The phloem serves as a major trafficking pathway for assimilates, viruses, RNA, plant hormones, metabolites, and proteins with functions ranging from synthesis to metabolism to signaling. The study of signaling compounds within the phloem is essential for our understanding of plant communication of environmental cues. Determining the nature of signals and the mechanisms by which they are communicated through the phloem will lead to a more complete understanding of plant development and plant responses to stress. In our analysis of Arabidopsis phloem exudates, we had identified several lipid-binding proteins as well as fatty acids and lipids. The latter are not typically expected in the aqueous environment of sieve elements. Hence, lipid transport in the phloem has been given little attention until now. Long-distance transport of hydrophobic compounds in an aqueous system is not without precedence in biological systems: a variety of lipids is found in human blood and are often bound to proteins. Some lipid-protein complexes are transported to other tissues for storage, use, modification, or degradation, others serve as messengers and modulate transcription factor activity. By simple analogy it raises the possibility that lipids and the respective lipid-binding proteins in the phloem serve similar functions in plants and play an important role in stress and developmental signaling. Here, we introduce the lipid-binding proteins and the lipids we found in the phloem and discuss the possibility that they may play an important role in developmental and stress signaling.

Lipid-Lowering Pharmaceutical Clofibrate Inhibits Human Sweet Taste

OpenAIRE

Kochem, Matthew; Breslin, Paul A.S.

2016-01-01

T1R2-T1R3 is a heteromeric receptor that binds sugars, high potency sweeteners, and sweet taste blockers. In rodents, T1R2-T1R3 is largely responsible for transducing sweet taste perception. T1R2-T1R3 is also expressed in non-taste tissues, and a growing body of evidence suggests that it helps regulate glucose and lipid metabolism. It was previously shown that clofibric acid, a blood lipid-lowering drug, binds T1R2-T1R3 and inhibits its activity in vitro. The purpose of this study was to dete...

Data supporting beta-amyloid dimer structural transitions and protein–lipid interactions on asymmetric lipid bilayer surfaces using MD simulations on experimentally derived NMR protein structures

Directory of Open Access Journals (Sweden)

Sara Y. Cheng

2016-06-01

Full Text Available This data article supports the research article entitled “Maximally Asymmetric Transbilayer Distribution of Anionic Lipids Alters the Structure and interaction with Lipids of an Amyloidogenic Protein Dimer Bound to the Membrane Surface” [1]. We describe supporting data on the binding kinetics, time evolution of secondary structure, and residue-contact maps of a surface-absorbed beta-amyloid dimer protein on different membrane surfaces. We further demonstrate the sorting of annular and non-annular regions of the protein/lipid bilayer simulation systems, and the correlation of lipid-number mismatch and surface area per lipid mismatch of asymmetric lipid membranes.

Ameliorating reactive oxygen species-induced in vitro lipid peroxidation in brain, liver, mitochondria and DNA damage by Zingiber officinale Roscoe.

Science.gov (United States)

Ajith, T A

2010-01-01

Iron is an essential nutrient for a number of cellular activities. However, excess cellular iron can be toxic by producing reactive oxygen species (ROS) such as superoxide anion (O(2) (-)) and hydroxyl radical (HO(·)) that damage proteins, lipids and DNA. Mutagenic and genotoxic end products of lipid peroxidation can induce the decline of mitochondrial respiration and are associated with various human ailments including aging, neurodegenerative disorders, cancer etc. Zingiber officinale Roscoe (ginger) is a widely used spice around the world. The protective effect of aqueous ethanol extract of Z. officinale against ROS-induced in vitro lipid peroxidation and DNA damage was evaluated in this study. The lipid peroxidation was induced by hydroxyl radical generated from Fenton's reaction in rat liver and brain homogenates and mitochondrial fraction (isolated from rat liver). The DNA protection was evaluated using H(2)O(2)-induced changes in pBR-322 plasmid and Fenton reaction-induced DNA fragmentation in rat liver. The results indicated that Z. officinale significantly (Pofficinale in the liver homogenate was 94 %. However, the extract could partially alleviate the DNA damage. The protective mechanism can be correlated to the radical scavenging property of Z. officinale. The results of the study suggest the possible nutraceutical role of Z. officinale against the oxidative stress induced human ailments.

Supplementation with complex milk lipids during brain development promotes neuroplasticity without altering myelination or vascular density

Directory of Open Access Journals (Sweden)

Rosamond B. Guillermo

2015-03-01

Full Text Available Background: Supplementation with complex milk lipids (CML during postnatal brain development has been shown to improve spatial reference learning in rats. Objective: The current study examined histo-biological changes in the brain following CML supplementation and their relationship to the observed improvements in memory. Design: The study used the brain tissues from the rats (male Wistar, 80 days of age after supplementing with either CML or vehicle during postnatal day 10–80. Immunohistochemical staining of synaptophysin, glutamate receptor-1, myelin basic protein, isolectin B-4, and glial fibrillary acidic protein was performed. The average area and the density of the staining and the numbers of astrocytes and capillaries were assessed and analysed. Results: Compared with control rats, CML supplementation increased the average area of synaptophysin staining and the number of GFAP astrocytes in the CA3 sub-region of the hippocampus (p<0.01, but not in the CA4 sub-region. The supplementation also led to an increase in dopamine output in the striatum that was related to nigral dopamine expression (p<0.05, but did not alter glutamate receptors, myelination or vascular density. Conclusion: CML supplementation may enhance neuroplasticity in the CA3 sub-regions of the hippocampus. The brain regions-specific increase of astrocyte may indicate a supporting role for GFAP in synaptic plasticity. CML supplementation did not associate with postnatal white matter development or vascular remodelling.

Effects of acute nicotine on hemodynamics and binding of [11C]raclopride to dopamine D2,3 receptors in pig brain.

Science.gov (United States)

Cumming, Paul; Rosa-Neto, Pedro; Watanabe, Hideaki; Smith, Donald; Bender, Dirk; Clarke, Paul B S; Gjedde, Albert

2003-07-01

Positive reinforcing properties of nicotine and the psychostimulants have been attributed to elevated dopamine release in the basal ganglia. It is well known that the specific binding of [(11)C]raclopride to dopamine D(2,3) receptors in living striatum is reduced by cocaine and amphetamines, revealing increased competition between endogenous dopamine and [(11)C]raclopride for dopamine D(2,3) receptors. However, the sensitivity of [(11)C]raclopride binding to nicotine-induced dopamine release is less well documented. In order to provide the basis for mapping effects of nicotine, we first optimized reference tissue methods for quantifying [(11)C]raclopride binding sites in striatum of living pigs (n = 16). In the same animals, the rate of cerebral blood flow (CBF) was mapped using [(15)O]water. Neither a low dose of nicotine (50 mu kg(-1), iv) nor a high dose of nicotine (500 microg kg(-1), iv) altered CBF in the pig brain, an important condition for calculating the binding of radioligands when using a reference tissue to estimate the free ligand concentration. The methods of Logan and of Lammertsma were compared using the cerebellum or the occipital cortex as reference tissues for calculating the binding potential (pB) of [(11)C]raclolpride in brain. Irrespective of the method used, the mean undrugged baseline pB in striatum (ca. 2.0) was significantly asymmetric, with highest binding in the left caudate and right putamen. Test-retest estimates of pB were stable. Subtraction of Logan pB maps revealed that the low dose of nicotine reduced the pB of [(11)C]raclopride by 10% in a cluster of voxels in the left anteroventral striatum, but this effect did not persist after correction for multiple comparisons. The high dose of nicotine (n = 9) acutely reduced pB by 10% bilaterally in the ventral striatum; 3 h after the high nicotine dose, the reductions had shifted dorsally and caudally into the caudate and putamen. Evidently, nicotine challenge enhances the competition

Stealth lipid polymer hybrid nanoparticles loaded with rutin for effective brain delivery - comparative study with the gold standard (Tween 80): optimization, characterization and biodistribution.

Science.gov (United States)

Ishak, Rania A H; Mostafa, Nada M; Kamel, Amany O

2017-11-01

The blood-brain barrier is considered the leading physiological obstacle hindering the transport of neurotherapeutics to brain cells. The application of nanotechnology coupled with surfactant coating is one of the efficacious tactics overcoming this barrier. The aim of this study was to develop lipid polymer hybrid nanoparticles (LPHNPs), composed of a polymeric core and a phospholipid shell entangled, for the first time, with PEG-based surfactants (SAA) viz. TPGS or Solutol HS 15 in comparison with the gold standard Tween 80, aiming to enhance brain delivery and escape opsonization. LPHNPs were successfully prepared using modified single-step nanoprecipitation technique, loaded with the flavonoid rutin (RU), extracted from the flowers of Calendula officinalis L., and recently proved as a promising anti-Alzheimer. The effect of the critical process parameters (CPP) viz. PLGA amount, W lecithin /W PLGA ratio, and Tween 80 concentration on critical quality attributes (CQA); entrapment, size and size distribution, was statistically analyzed via design of experiments, and optimized using the desirability function. The optimized CPP were maintained while substituting Tween 80 with other PEG-SAA. All hybrid particles exhibited spherical shape with perceptible lipid shells. The biocompatibility of the prepared NPs was confirmed by hemolysis test. The pharmacokinetic assessments, post-intravenous administration to rats, revealed a significant higher RU bioavailability for NPs relative to drug solution. Biodistribution studies proved non-significant differences in RU accumulation within brain, but altered phagocytic uptake among various LPHNPs. The present study endorses the successful development of LPHNPs using PEG-SAA, and confirms the prospective applicability of TPGS and Solutol in enhancing brain delivery.

Adsorption of human tear lipocalin to human meibomian lipid films.

Science.gov (United States)

Millar, Thomas J; Mudgil, Poonam; Butovich, Igor A; Palaniappan, Chendur K

2009-01-01

Tear lipocalin (Tlc) is a major lipid binding protein in tears and is thought to have an important role in stabilizing the Meibomian lipid layer by transferring lipids to it from the aqueous layer or ocular surface, or by adsorbing to it directly. These possible roles have been investigated in vitro using human Tlc. Tlc was purified from human tears by size exclusion chromatography followed by ion exchange chromatography. Three additional samples of the Tlc were prepared by lipidation, delipidation, and relipidation. The lipids extracted from the purified Tlc were analyzed by HPLC-MS followed by fragmentation. Adsorption of these different forms of Tlc to a human Meibomian lipid film spread on the surface of an artificial tear buffer in a Langmuir trough were observed by recording changes in the pressure with time (Pi-T profile) and monitoring the appearance of the film microscopically. These results were compared with similar experiments using a bovine Meibomian lipid film. The results indicated that Tlc binds slowly to a human Meibomian lipid film compared with lysozyme or lactoferrin, even at 37 degrees C. The adsorption of Tlc to a human Meibomian lipid film was very different from its adsorption to a bovine Meibomian lipid film, indicating the nature of the lipids in the film is critical to the adsorption process. Similarly, the different forms of Tlc had quite distinct adsorption patterns, as indicated both by changes in Pi-T profiles and the microscopic appearance of the films. It was concluded that human Tlc was capable of adsorbing to and penetrating into a Meibomian lipid layer, but this process is very complex and depends on both the types of lipids bound to Tlc and the lipid complement comprising the Meibomian lipid film.

Adsorption of Human Tear Lipocalin to Human Meibomian Lipid Films

Science.gov (United States)

Millar, Thomas J.; Mudgil, Poonam; Butovich, Igor A.; Palaniappan, Chendur K.

2009-01-01

Purpose Tear lipocalin (Tlc) is a major lipid binding protein in tears and is thought to have an important role in stabilizing the Meibomian lipid layer by transferring lipids to it from the aqueous layer or ocular surface, or by adsorbing to it directly. These possible roles have been investigated in vitro using human Tlc. Methods Tlc was purified from human tears by size exclusion chromatography followed by ion exchange chromatography. Three additional samples of the Tlc were prepared by lipidation, delipidation, and relipidation. The lipids extracted from the purified Tlc were analyzed by HPLC-MS followed by fragmentation. Adsorption of these different forms of Tlc to a human Meibomian lipid film spread on the surface of an artificial tear buffer in a Langmuir trough were observed by recording changes in the pressure with time (∏-T profile) and monitoring the appearance of the film microscopically. These results were compared with similar experiments using a bovine Meibomian lipid film. Results The results indicated that Tlc binds slowly to a human Meibomian lipid film compared with lysozyme or lactoferrin, even at 37°C. The adsorption of Tlc to a human Meibomian lipid film was very different from its adsorption to a bovine Meibomian lipid film, indicating the nature of the lipids in the film is critical to the adsorption process. Similarly, the different forms of Tlc had quite distinct adsorption patterns, as indicated both by changes in ∏-T profiles and the microscopic appearance of the films. Conclusions It was concluded that human Tlc was capable of adsorbing to and penetrating into a Meibomian lipid layer, but this process is very complex and depends on both the types of lipids bound to Tlc and the lipid complement comprising the Meibomian lipid film. PMID:18757516

sigma opiates and certain antipsychotic drugs mutually inhibit (+)-[3H]SKF 10,047 and [3H]haloperidol binding in guinea pig brain membranes

International Nuclear Information System (INIS)

Tam, S.W.; Cook, L.

1984-01-01

The relationship between binding of antipsychotic drugs and sigma psychotomimetic opiates to binding sites for the sigma agonist (+)-[ 3 H]SKF 10,047 (N-allylnormetazocine) and to dopamine D 2 sites was investigated. In guinea pig brain membranes, (+)-[ 3 H]SKF 10,047 bound to single class of sites with a K/sub d/ of 4 x 10 -8 M and a B/sub max/ of 333 fmol/mg of protein. This binding was different from μ, kappa, or delta opiate receptor binding. It was inhibited by opiates that produce psychotomimetic activities but not by opiates that lack such activities. Some antipsychotic drugs inhibited (+)-[ 3 H]SKF 10,047 binding with high to moderate affinities in the following order of potency: haloperidol > perphenazine > fluphenazine > acetophenazine > trifluoperazine > molindone greater than or equal to pimozide greater than or equal to thioridazine greater than or equal to chlorpromazine greater than or equal to triflupromazine. However, there were other antipsychotic drugs such as spiperone and clozapine that showed low affinity for the (+)-[ 3 H]SKF 10,047 binding sites. Affinities of antipsychotic drugs for (+)-[ 3 H]SKF 10,047 binding sites did not correlate with those for [ 3 H]spiperone (dopamine D 2 ) sites. [ 3 H]-Haloperidol binding in whole brain membranes was also inhibited by the sigma opiates pentazocine, cyclazocine, and (+)-[ 3 H]SKF 10,047. In the striatum, about half of the saturable [ 3 H]haloperidol binding was to [ 3 H]spiperone (D 2 ) sites and the other half was to sites similar to (+)-[ 3 H]SKF 10,047 binding sites. 15 references, 4 figures, 1 table

Inhibition of β-bungarotoxin binding to brain membranes by mast cell degranulating peptide, toxin I, and ethylene glycol bis(β-aminoethyl ether)-N,N,N',N'-tetraacetic acid

International Nuclear Information System (INIS)

Schmidt, R.R.; Betz, H.; Rehm, H.

1988-01-01

The presynaptically active snake venom neurotoxin β-bungarotoxin (β-Butx) is known to affect neurotransmitter release by binding to a subtype of voltage-activated K + channels. Here the authors show that mast cell degranulating (MCD) peptide from bee venom inhibits the binding of 125 I-labeled β-Butx to chick and rat brain membranes with apparent K/sub i/ values of 180 nM and 1100 nM, respectively. The mechanisms of inhibition of MCD peptide is noncompetitive, as is inhibition of 125 I-β-Butx binding by the protease inhibitor homologue from mamba venom, toxin I. β-Butx and its binding antagonists thus bind to different sites of the same membrane protein. Removal of Ca 2+ by ethylene glycol bis(β-aminoethyl ether)-N,N,N',N'-tetraacetic acid inhibits the binding of 125 I-β-Butx by lowering its affinity to brain membranes

The hydroxylated form of docosahexaenoic acid (DHA-H) modifies the brain lipid composition in a model of Alzheimer's disease, improving behavioral motor function and survival.

Science.gov (United States)

Mohaibes, Raheem J; Fiol-deRoque, María A; Torres, Manuel; Ordinas, Margarita; López, David J; Castro, José A; Escribá, Pablo V; Busquets, Xavier

2017-09-01

We have compared the effect of the commonly used ω-3 fatty acid, docosahexaenoic acid ethyl ester (DHA-EE), and of its 2-hydroxylated DHA form (DHA-H), on brain lipid composition, behavior and lifespan in a new human transgenic Drosophila melanogaster model of Alzheimer's disease (AD). The transgenic flies expressed human Aβ42 and tau, and the overexpression of these human transgenes in the CNS of these flies produced progressive defects in motor function (antigeotaxic behavior) while reducing the animal's lifespan. Here, we demonstrate that both DHA-EE and DHA-H increase the longer chain fatty acids (≥18C) species in the heads of the flies, although only DHA-H produced an unknown chromatographic peak that corresponded to a non-hydroxylated lipid. In addition, only treatment with DHA-H prevented the abnormal climbing behavior and enhanced the lifespan of these transgenic flies. These benefits of DHA-H were confirmed in the well characterized transgenic PS1/APP mouse model of familial AD (5xFAD mice), mice that develop defects in spatial learning and in memory, as well as behavioral deficits. Hence, it appears that the modulation of brain lipid composition by DHA-H could have remedial effects on AD associated neurodegeneration. This article is part of a Special Issue entitled: Membrane Lipid Therapy: Drugs Targeting Biomembranes edited by Pablo V. Escribá. Copyright © 2017. Published by Elsevier B.V.

Effect of hyperbaric oxygen on lipid peroxidation and visual development in neonatal rats with hypoxia-ischemia brain damage.

Science.gov (United States)

Chen, Jing; Chen, Yan-Hui; Lv, Hong-Yan; Chen, Li-Ting

2016-07-01

The aim of the present study was to investigate the effect of hyperbaric oxygen (HBO) on lipid peroxidation and visual development in a neonatal rat model of hypoxic-ischemic brain damage (HIBD). The rat models of HIBD were established by delayed uterus dissection and were divided randomly into two groups (10 rats each): HIBD and HBO-treated HIBD (HIBD+HBO) group. Another 20 rats that underwent sham-surgery were also divided randomly into the HBO-treated and control groups. The rats that underwent HBO treatment received HBO (0.02 MPa, 1 h/day) 24 h after the surgery and this continued for 14 days. When rats were 4 weeks old, their flash visual evoked potentials (F-VEPs) were monitored and the ultrastructures of the hippocampus were observed under transmission electron microscope. The levels of superoxide dismutase (SOD) and malonyldialdehyde (MDA) in the brain tissue homogenate were detected by xanthine oxidase and the thiobarbituric acid colorimetric method. Compared with the control group, the ultrastructures of the pyramidal neurons in the hippocampal CA3 area were distorted, the latencies of F-VEPs were prolonged (P0.05). HBO enhances antioxidant capacity and reduces the ultrastructural damage induced by hypoxic-ischemia, which may improve synaptic reconstruction and alleviate immature brain damage to promote the habilitation of brain function.

Regional in vivo binding of (/sup 3/H)N-propylnorapomorphine in the mouse brain. Evidence for labelling of central dopamine receptors

Energy Technology Data Exchange (ETDEWEB)

Koehler, C; Fuxe, K; Ross, S B [Astra Pharmaceuticals AB, Soedertaelje (Sweden)

1981-07-10

Tail vein injections of (/sup 3/H)N-propylnorapomorphine ((/sup 3/H)NPA) in male mice resulted in a dose-related accumulation of radioactivity in the following brain regions: striatum (max), olfactory tubercle and cerebellum (min). The specific binding was saturable with increasing concentrations of the drug and stereospecifically displaced by (+)butaclamol. Dopamine agonists (apomorphine, NPA and bromocriptine) and antagonists (spiperone, haloperidol, (+)butaclamol and l-sulpiride) all caused dose-dependent prevention of (/sup 3/H)NPA binding. Mianserin, phenoxybenzamine and propranolol did not prevent the in vivo (/sup 3/H)NPA binding suggesting that (/sup 3/H)NPA binds specifically to dopamine receptors in the striatum and the olfactory tubercle of the mouse.

Imaging mass spectrometry (IMS) of cortical lipids from preclinical to severe stages of Alzheimer's disease.

Science.gov (United States)

Gónzalez de San Román, E; Manuel, I; Giralt, M T; Ferrer, I; Rodríguez-Puertas, R

2017-09-01

Alzheimer's disease (AD) is a progressive neurodegenerative disease affecting millions of patients worldwide. Previous studies have demonstrated alterations in the lipid composition of lipid extracts from plasma and brain samples of AD patients. However, there is no consensus regarding the qualitative and quantitative changes of lipids in brains from AD patients. In addition, the recent developments in imaging mass spectrometry methods are leading to a new stage in the in situ analysis of lipid species in brain tissue slices from human postmortem samples. The present study uses the matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS), permitting the direct anatomical analysis of lipids in postmortem brain sections from AD patients, which are compared with the intensity of the lipid signal in samples from matched subjects with no neurological diseases. The frontal cortex samples from AD patients were classified in three groups based on Braak's histochemical criteria, ranging from non-cognitively impaired patients to those severely affected. The main results indicate a depletion of different sulfatide lipid species from the earliest stages of the disease in both white and gray matter areas of the frontal cortex. Therefore, the decrease in sulfatides in cortical areas could be considered as a marker of the disease, but may also indicate neurochemical modifications related to the pathogenesis of the disease. This article is part of a Special Issue entitled: Membrane Lipid Therapy: Drugs Targeting Biomembranes edited by Pablo V. Escribá. Copyright © 2017 Elsevier B.V. All rights reserved.

Ketone-body utilization and lipid synthesis by developing rat brain—a comparison between in vivo and in vitro experiments

NARCIS (Netherlands)

Klein, W.; Lopes-Cardozo, M.

1984-01-01

The distribution of ketone bodies between oxidation and lipid synthesis was analysed in homogenates of developing rat brain. The capacity for lipid synthesis of homogenized or minced brain preparations was compared with rates of lipid synthesis in vivo, assessed by incorporation of ³H from

Imaging MALDI mass spectrometry using an oscillating capillary nebulizer matrix coating system and its application to analysis of lipids in brain from a mouse model of Tay-Sachs/Sandhoff disease.

Science.gov (United States)

Chen, Yanfeng; Allegood, Jeremy; Liu, Ying; Wang, Elaine; Cachón-Gonzalez, Begoña; Cox, Timothy M; Merrill, Alfred H; Sullards, M Cameron

2008-04-15

The quality of tissue imaging by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) depends on the effectiveness of the matrix deposition, especially for lipids that may dissolve in the solvent used for the matrix application. This article describes the use of an oscillating capillary nebulizer (OCN) to spray small droplets of matrix aerosol onto the sample surface for improved matrix homogeneity, reduced crystal size, and controlled solvent effects. This system was then applied to the analysis of histological slices of brains from mice with homozygous disruption of the hexb gene (hexb-/-), a model of Tay-Sachs and Sandhoff disease, versus the functionally normal heterozygote (hexb+/-) by imaging MALDI-MS. This allowed profiling and localization of many different lipid species, and of particular interest, ganglioside GM2, asialo-GM2 (GA2), and sulfatides (ST). The presence of these compounds was confirmed by analysis of brain extracts using electrospray ionization in conjunction with tandem mass spectrometry (MS/MS). The major fatty acid of the ceramide backbone of both GM2 and GA2 was identified as stearic acid (18:0) versus nervonic acid (24:1) for ST by both tissue-imaging MS and ESI-MS/MS. GM2 and GA2 were highly elevated in hexb-/- and were both localized in the granular cell region of the cerebellum. ST, however, was localized mainly in myelinated fiber (white matter) region of the cerebellum as well as in the brain stem with a relatively uniform distribution and had similar relative signal intensity for both hexb+/- and hexb-/- brain. It was also observed that there were distinct localizations for numerous other lipid subclasses; hence, imaging MALDI-MS could be used for "lipidomic" studies. These results illustrate the usefulness of tissue-imaging MALDI-MS with matrix deposition by OCN for histologic comparison of lipids in tissues such as brains from this mouse model of Tay-Sachs and Sandhoff disease.

Regional brain [(11)C]carfentanil binding following tobacco smoking.

Science.gov (United States)

Domino, Edward F; Hirasawa-Fujita, Mika; Ni, Lisong; Guthrie, Sally K; Zubieta, Jon Kar

2015-06-03

To determine if overnight tobacco abstinent carriers of the AG or GG (*G) vs. the AA variant of the human mu opioid receptor (OPRM1) A118G polymorphism (rs1799971) differ in [(11)C]carfentanil binding after tobacco smoking. Twenty healthy American male smokers who abstained from tobacco overnight were genotyped and completed positron emission tomography (PET) scans with the mu opioid receptor agonist, [(11)C]carfentanil. They smoked deniconized (denic) and average nicotine (avnic) cigarettes during the PET scans. Smoking avnic cigarette decreased the binding potential (BPND) of [(11)C]carfentanil in the right medial prefrontal cortex (mPfc; 6, 56, 18), left anterior medial prefrontal cortex (amPfc; -2, 46, 44), right ventral striatum (vStr; 16, 3, -10), left insula (Ins; -42, 10, -12), right hippocampus (Hippo; 18, -6, -14) and left cerebellum (Cbl; -10, -88, -34), and increased the BPND in left amygdala (Amy; -20, 0, -22), left putamen (Put; -22, 10, -6) and left nucleus accumbens (NAcc; -10, 12, -8). In the AA allele carriers, avnic cigarette smoking significantly changed the BPND compared to after denic smoking in most brain areas listed above. However in the *G carriers the significant BPND changes were confirmed in only amPfc and vStr. Free mu opioid receptor availability was significantly less in the *G than the AA carriers in the Amy and NAcc. The present study demonstrates that BPND changes induced by avnic smoking in OPRM1 *G carriers were blunted compared to the AA carriers. Also *G smokers had less free mu opioid receptor availability in Amy and NAcc. Copyright © 2015 Elsevier Inc. All rights reserved.

Backbone and sidechain 1H, 13C and 15N resonance assignments of the human brain-type fatty acid binding protein (FABP7) in its apo form and the holo forms binding to DHA, oleic acid, linoleic acid and elaidic acid

DEFF Research Database (Denmark)