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Sample records for 5-hydroxytryptamine uptake sites

  1. In vivo labeling of 5-hydroxytryptamine uptake sites in mouse brain with ( sup 3 H)-6-nitroquipazine

    SciTech Connect

    Hashimoto, K.; Goromaru, T. )

    1990-10-01

    6-Nitroquipazine (DU 24565; 6-nitro 2-piperazinylquinoline) is a very potent 5-hydroxytryptamine (5-HT; serotonin) uptake inhibitor. It has been demonstrated very recently that (3H)-6-nitroquipazine is a suitable radioligand for studying 5-HT uptake sites. The present study evaluates (3H)6-nitroquipazine as a radioligand for in vivo labeling of 5-HT uptake sites in mouse brain. Very high uptake of radioactivity in the brain after i.v. administration of (3H)-6-nitroquipazine was shown. Regional distribution of the radioactivity in mouse brain 3 hr after injection of (3H)-6-nitroquipazine was in the order (highest to lowest) hypothalamus greater than midbrain greater than striatum greater than hippocampus greater than cerebral cortex greater than medulla oblongata greater than cerebellum. The regional distribution of in vivo (3H)-6-nitroquipazine binding in mouse brain was highly correlated with that in rat brain obtained from previous in vitro binding studies. Coadministration of carrier 6-nitroquipazine (5 mg/kg) significantly decreased the radioactivity in the hypothalamus, whereas that in the cerebellum and cerebral cortex was increased. Because the cerebellum has very low density of (3H)-6-nitroquipazine binding sites, the radioactivity in the cerebellum could, therefore, reflect the amount on nonspecific binding and free ligand. Kinetic studies showed highest in vivo specific binding 1 hr after injection of (3H)-6-nitroquipazine and slow clearance of specific binding. Specific binding in the hypothalamus was inhibited in a stereoselective manner by the stereoisomers of norzimelidine. Furthermore, specific binding in the hypothalamus was reduced by several 5-HT uptake inhibitors, in a dose-dependent manner.

  2. Activation of human 5-hydroxytryptamine type 3 receptors via an allosteric transmembrane site.

    PubMed

    Lansdell, Stuart J; Sathyaprakash, Chaitra; Doward, Anne; Millar, Neil S

    2015-01-01

    In common with other members of the Cys-loop family of pentameric ligand-gated ion channels, 5-hydroxytryptamine type 3 receptors (5-HT3Rs) are activated by the binding of a neurotransmitter to an extracellular orthosteric site, located at the interface of two adjacent receptor subunits. In addition, a variety of compounds have been identified that modulate agonist-evoked responses of 5-HT3Rs, and other Cys-loop receptors, by binding to distinct allosteric sites. In this study, we examined the pharmacological effects of a group of monoterpene compounds on recombinant 5-HT3Rs expressed in Xenopus oocytes. Two phenolic monoterpenes (carvacrol and thymol) display allosteric agonist activity on human homomeric 5-HT3ARs (64 ± 7% and 80 ± 4% of the maximum response evoked by the endogenous orthosteric agonist 5-HT, respectively). In addition, at lower concentrations, where agonist effects are less apparent, carvacrol and thymol act as potentiators of responses evoked by submaximal concentrations of 5-HT. By contrast, carvacrol and thymol have no agonist or potentiating activity on the closely related mouse 5-HT3ARs. Using subunit chimeras containing regions of the human and mouse 5-HT3A subunits, and by use of site-directed mutagenesis, we have identified transmembrane amino acids that either abolish the agonist activity of carvacrol and thymol on human 5-HT3ARs or are able to confer this property on mouse 5-HT3ARs. By contrast, these mutations have no significant effect on orthosteric activation of 5-HT3ARs by 5-HT. We conclude that 5-HT3ARs can be activated by the binding of ligands to an allosteric transmembrane site, a conclusion that is supported by computer docking studies. PMID:25338672

  3. Relative activities on and uptake by human blood platelets of 5-hydroxytryptamine and several analogues

    PubMed Central

    Born, G. V. R.; Juengjaroen, Kanchana; Michal, F.

    1972-01-01

    1. The specificity of platelet receptor sites for 5-HT uptake and for the rapid morphological change and aggregation was investigated with 5-hydroxy-tryptamine (5-HT) and seventeen analogues as well as with some antagonists of 5-HT. 2. The analogues, with the exception of 5-hydroxy-N'N'-dibutyltryptamine, caused the rapid morphological change in platelets. In concentrations below those needed to produce the agonistic action (viz. 0.05-2.0 μM), these analogues themselves inhibited competitively the shape change caused by 5-HT. 3. The velocity of change in shape caused by 5-HT was reduced in low Na media. 4. Ten analogues produced platelet aggregation; three of these, viz. 5-methoxy-α-methyltryptamine, 5-hydroxy-α-methyltryptamine and 5-hydroxy-N'N'-diisopropyltryptamine), were approximately equipotent with 5-HT. Six analogues did not induce platelet aggregation. 5. All the analogues which prevented the initial change in shape of platelets caused by 5-HT also inhibited its aggregating effect, apparently competitively with low Ki values (0.02-1.6 μM). 6. As with the inhibition of shape change, the inhibition of aggregation shows relatively low structural specificity of the receptor site. 7. Methysergide was a potent inhibitor of shape change and aggregation (Ki∼0.03 μM); imipramine was much less inhibitory (Ki∼5-10 μM). 8. Only one analogue (5-hydroxy-α-methyltryptamine) was taken up like 5-HT by platelets. All the other analogues inhibited the uptake of 5-HT by platelets (Ki=0.2-2.7 μM). 9. Methysergide was a weak inhibitor of 5-HT uptake (Ki∼125 μM) whereas imipramine was very effective (Ki∼0.3 μM). 10. Our results show that the initial change in shape of platelets is required for and precedes aggregation. The structural specificity of the platelet receptor concerned with shape change and aggregation caused by 5-HT appears low whereas the uptake mechanism is a highly specific one. The uptake probably proceeds through more than one step, the

  4. 5-Carboxamide tryptamine, a compound with high affinity for 5-hydroxytryptamine1 binding sites, dilates arterioles and constricts arteriovenous anastomoses.

    PubMed Central

    Saxena, P. R.; Verdouw, P. D.

    1985-01-01

    The effects of 5-carboxamide tryptamine, which activates non-5-hydroxytryptamine2-'atypical' receptors for 5-hydroxytryptamine (5-HT) in the dog saphenous vein, was studied on the complete distribution of cardiac output and common carotid blood flow in anaesthetized pigs. The drug was infused for 10 min at the rate of 0.025, 0.1 and 0.4 micrograms kg-1 min-1 either intravenously (cardiac output distribution) or intra-arterially (carotid distribution). 5-Carboxamide tryptamine decreased arterial blood pressure due to a reduction of cardiac output. This reduction was confined to its arteriovenous anastomotic component; the component used for the tissue perfusion (nutrient part) in fact increased. Similar changes were observed in the carotid blood flow distribution. Vasodilation was observed in several tissues, but the skin, ears and stomach responded most prominently. The effects of 5-carboxamide tryptamine on the carotid distribution were not significantly modified by cyproheptadine (1 mg kg-1). It is concluded that, like 5-HT, 5-carboxamide tryptamine constricts arteriovenous anastomoses and dilates arterioles by activating non-5-HT2-'atypical' receptors. These 'atypical' 5-HT receptors appear to be of the 5-HT1 type since both 5-carboxamide tryptamine and BEA 1654, a new piperazine derivative, produced similar vascular effects in the carotid bed of the pig and also showed a high and selective affinity for the 5-HT1 binding sites. PMID:3978321

  5. Neuropharmacology of 5-hydroxytryptamine

    PubMed Central

    Richard Green, A

    2006-01-01

    This review outlines the history of our knowledge of the neuropharmacology of 5-hydroxytryptamine (5-HT; serotonin), focusing primarily on the work of U.K. scientists. The existence of a vasoconstrictive substance in the blood has been known for over 135 years. The substance was named serotonin and finally identified as 5-HT in 1949. The presence of 5-HT in the brain was reported by Gaddum in 1954 and it was Gaddum who also demonstrated that the action of 5-HT (in the gut) was antagonised by the potent hallucinogen lysergic acid diethylamide. This provoked the notion that 5-HT played a pivotal role in the control of mood and subsequent investigations have generally confirmed this hypothesis. Over the last 50 years a good understanding has been gained of the mechanisms involved in control of the storage, synthesis and degradation of 5-HT in the brain. Knowledge has also been gained on control of the functional activity of this monoamine, often by the use of behavioural models. A considerable literature also now exists on the mechanisms by which many of the drugs used to treat psychiatric illness alter the functional activity of 5-HT, particularly the drugs used to treat depression. Over the last 20 years the number of identified 5-HT receptor subtypes has increased from 2 to 14, or possibly more. A major challenge now is to utilise this knowledge to develop receptor-specific drugs and use the information gained to better treat central nervous system disorders. PMID:16402098

  6. The influence of 5-hydroxytryptamine re-uptake blockade on CCK receptor antagonist effects in the rat elevated zero-maze.

    PubMed

    Bickerdike, M J; Marsden, C A; Dourish, C T; Fletcher, A

    1994-12-27

    In this study, the elevated zero-maze model of anxiety was used to investigate CCK receptor antagonist effects on the behaviour of male Lister-hooded rats and to demonstrate, by administering antagonists in the presence or absence of selective 5-hydroxytryptamine (5-HT) re-uptake inhibitors, the involvement of 5-HT in the mediation of these effects. Devazepide, a selective CCKA receptor antagonist, L-365,260 (3R(+)-N-2,3-dihydro-1-methyl-2-oxo-5-phenyl-1H-1,4-benzodiazepin- 3-yl-N1- (3-methyl-phenyl)urea) or CI-988 (4-([2-[[3-(1H-indol-3-yl)-2-methyl-1- oxo-2-[[(tricyclo[3.3.1.1.(3.7)]-dec-2-yloxy)-carbonyl]-amin o]- propyl]-amino]-1-phenylethyl]-amino)-4-oxo-[R-(R*,R*)]-butanoate- N-methyl-D-glucamine), both selective CCKB receptor antagonists, were administered 30 min prior to testing. Behavioural analysis during testing included measures of risk-assessment behaviours (e.g. stretched-attend posture) in addition to time spent on the open quadrants. Devazepide induced significant anxiolytic effects, whereas CI-988 produced inconsistent results and L-365,260 was ineffective. When administered simultaneously with the 5-HT re-uptake inhibitors zimelidine or Wy 27587 (N-[[[1-[(6- fluoro-2-naphthalenyl)methyl]-4-piperidinyl]amino] carbonyl]-3-pyridine carboxamide methyl sulphonate salt), the significant anxiolytic effect induced by devazepide was dose-dependently and significantly attenuated. Zimelidine and Wy27587 had little effect alone on zero-maze behaviour at the lower of two doses given. These data show that the elevated zero-maze, in conjunction with the analysis of 'risk-assessment' behaviours, is an anxiety model which is sensitive to the anxiolytic effects of CCK receptor antagonism.(ABSTRACT TRUNCATED AT 250 WORDS)

  7. 5-Hydroxytryptamine2A serotonin receptors in the primate cerebral cortex: possible site of action of hallucinogenic and antipsychotic drugs in pyramidal cell apical dendrites.

    PubMed

    Jakab, R L; Goldman-Rakic, P S

    1998-01-20

    To identify the cortical sites where 5-hydroxytryptamine2A (5-HT2A) serotonin receptors respond to the action of hallucinogens and atypical antipsychotic drugs, we have examined the cellular and subcellular distribution of these receptors in the cerebral cortex of macaque monkeys (with a focus on prefrontal areas) by using light and electron microscopic immunocytochemical techniques. 5-HT2A receptor immunoreactivity was detected in all cortical layers, among which layers II and III and layers V and VI were intensely stained, and layer IV was weakly labeled. The majority of the receptor-labeled cells were pyramidal neurons and the most intense immunolabeling was consistently confined to their parallelly aligned proximal apical dendrites that formed two intensely stained bands above and below layer IV. In double-label experiments, 5-HT2A label was found in calbindin D28k-positive, nonphosphorylated-neurofilament-positive, and immuno-negative pyramidal cells, suggesting that probably all pyramidal cells express 5-HT2A receptors. 5-HT2A label was also found in large- and medium-size interneurons, some of which were immuno-positive for calbindin. 5-HT2A receptor label was also associated with axon terminals. These findings reconcile the data on the receptor's cortical physiology and localization by (i) establishing that 5-HT2A receptors are located postsynaptically and presynaptically, (ii) demonstrating that pyramidal neurons constitute the major 5-HT2A-receptor-expressing cells in the cortex, and (iii) supporting the view that the apical dendritic field proximal to the pyramidal cell soma is the "hot spot" for 5-HT2A-receptor-mediated physiological actions relevant to normal and "psychotic" functional states of the cerebral cortex.

  8. 5-Hydroxytryptamine (serotonin) in the gastrointestinal tract

    PubMed Central

    Gershon, Michael D.

    2013-01-01

    Purpose of review Although the gut contains most of the body’s 5-hydroxytryptamine (5-HT), many of its most important functions have recently been discovered. This review summarizes and directs attention to this new burst of knowledge. Recent findings Enteroendocrine cells have classically been regarded as pressure sensors, which secrete 5-HT to initiate peristaltic reflexes; nevertheless, recent data obtained from studies of mice that selectively lack 5-HT either in enterochromaffin cells (deletion of tryptophan hydroxylase 1 knockout; TPH1KO) or neurons (TPH2KO) imply that neuronal 5-HT is more important for constitutive gastrointestinal transit than that of enteroendocrine cells. The enteric nervous system of TPH2KO mice, however, also lacks a full complement of neurons; therefore, it is not clear whether slow transit in TPH2KO animals is due to their neuronal deficiency or absence of serotonergic neurotransmission. Neuronal 5-HT promotes the growth/maintenance of the mucosa as well as neurogenesis. Enteroendocrine cell derived 5-HT is an essential component of the gastrointestinal inflammatory response; thus, deletion of the serotonin transporter increases, whereas TPH1KO decreases the severity of intestinal inflammation. Enteroendocrine cell derived 5-HT, moreover, is also a hormone, which inhibits osteoblast proliferation and promotes hepatic regeneration. Summary New studies show that enteric 5-HT is a polyfunctional signalling molecule, acting both in developing and mature animals as a neurotransmitter paracrine factor, endocrine hormone and growth factor. PMID:23222853

  9. The major role of peripheral release of histamine and 5-hydroxytryptamine in formalin-induced nociception.

    PubMed

    Parada, C A; Tambeli, C H; Cunha, F Q; Ferreira, S H

    2001-01-01

    Formalin injected subcutaneously into the paw is a widely used model of pain. This procedure evokes a short-lasting period of flinching (phase 1) and a long-lasting period of intense flinching (phase 2) following a very short period of quiescence. Phase 2 has been extensively used to support the involvement of central (spinal cord) sensitization in inflammatory hyperalgesia. The present study evaluated the contribution of stimulation of peripheral nociceptors by the release of endogenous mediators at the site of lesion. The participation of histamine and 5-hydroxytryptamine was demonstrated by the treatment of the rat hindpaws with selective histamine H1 (pyrilamine and meclizine) and histamine H2 (cimetidine) receptor antagonists or selective 5-hydroxytryptamine(1A) (WAY100,135) and 5-hydroxytryptamine(4/3) (tropisetron) receptor antagonists. The co-administration of pyrilamine or meclizine with formalin (1%) significantly reduced phases 1 and 2, while cimetidine had no effect. Pyrilamine administration during the period of quiescence (10min after formalin administration) caused strong dose-related inhibition of phase 2. The co-administration of tropisetron with formalin caused a blockade of both phases, while with WAY100,135 caused only inhibition of the phase 2. In contrast, tropisetron administrated during the period of quiescence did not cause antinociception. Histamine and 5-hydroxytryptamine receptors could be strongly activated in naïve animals by administration of a mixture of both agonists or compound 48/80 (2microg/paw) which is known to release both mediators from mast cells. Pretreatment of the paws with a mast cell stabilizer, sodium cromoglycate, significantly reduced the second phase of the formalin injection model. From these results we suggest that phases 1 and 2 of the formalin test are dependent upon the ongoing afferent input. Furthermore, while histamine H1 participates in both phases, 5-hydroxytryptamine(4/3) participates in phase 1 and 5

  10. Catecholamines and 5-hydroxytryptamine in nervous tissue of cephalopods

    PubMed Central

    Juorio, A. V.

    1971-01-01

    1. Catecholamines and 5-hydroxytryptamine were measured fluorimetrically in nervous tissue of cephalopod molluscs. 2. The only catecholamines found present in nervous tissue of Eledone, Octopus and Sepia were dopamine and noradrenaline. The highest concentrations were found in the optic lobes and in the superior buccal lobe. The concentrations of dopamine and noradrenaline were smaller in other regions of the nervous tissue taken. 3. 5-Hydroxytryptamine was also found in most of the regions investigated. The highest concentration was found in the inferior buccal ganglia and in the optic lobes. 4. The administration of reserpine produced a marked decrease in the concentration of catecholamines and 5-hydroxytryptamine in octopod nervous tissue. 5. These findings suggest that dopamine, noradrenaline and 5-hydroxytryptamine may function as neurotransmitters in cephalopod molluscs. PMID:5558355

  11. Voltammetric detection of 5-hydroxytryptamine release in the rat brain.

    PubMed

    Hashemi, Parastoo; Dankoski, Elyse C; Petrovic, Jelena; Keithley, Richard B; Wightman, R M

    2009-11-15

    5-Hydroxytryptamine (5-HT) is an important molecule in the brain that is implicated in mood and emotional processes. In vivo, its dynamic release and uptake kinetics are poorly understood due to a lack of analytical techniques for its rapid measurement. Whereas fast-scan cyclic voltammetry with carbon fiber microelectrodes is used frequently to monitor subsecond dopamine release in freely moving and anesthetized rats, the electrooxidation of 5-HT forms products that quickly polymerize and irreversibly coat the carbon electrode surface. Previously described modifications of the electrochemical waveform allow stable and sensitive 5-HT measurements in mammalian tissue slice preparations and in the brain of fruit fly larvae. For in vivo applications in mammals, however, the problem of electrode deterioration persists. We identify the root of this problem to be fouling by extracellular metabolites such as 5-hydoxyindole acetic acid (5-HIAA), which is present in 200-1000 times the concentration of 5-HT and displays similar electrochemical properties, including filming of the electrode surface. To impede access of the 5-HIAA to the electrode surface, a thin layer of Nafion, a cation exchange polymer, has been electrodeposited onto cylindrical carbon-fiber microelectrodes. The presence of the Nafion film was confirmed with environmental scanning electron microscopy and was demonstrated by the diminution of the voltammetric signals for 5-HIAA as well as other common anionic species. The modified microelectrodes also display increased sensitivity to 5-HT, yielding a characteristic cyclic voltammogram that is easily distinguishable from other common electroactive brain species. The thickness of the Nafion coating and a diffusion coefficient (D) in the film for 5-HT were evaluated by measuring permeation through Nafion. In vivo, we used physiological, anatomical, and pharmacological evidence to validate the signal as 5-HT. Using Nafion-modified microelectrodes, we present the

  12. Involvement of 5-hydroxytryptamine7 receptors in inhibition of porcine myometrial contractility by 5-hydroxytryptamine

    PubMed Central

    Kitazawa, Takio; Kubo, Osamu; Satoh, Masami; Taneike, Tetsuro

    1998-01-01

    5-Hydroxytryptamine (5-HT; 1 nM–100 μM) concentration-dependently inhibited the amplitude and frequency of spontaneous contractions in longitudinal and circular muscles of the porcine myometrium. The circular muscle (EC50; 68–84 nM) was more sensitive than the longitudinal muscle (EC50; 1.3–1.44 μM) to 5-HT. To characterize the 5-HT receptor subtype responsible for inhibition of myometrial contractility, the effects of 5-HT receptor agonists on spontaneous contractions and of 5-HT receptor antagonists on inhibition by 5-HT were examined in circular muscle preparations.Pretreatment with tetrodotoxin (1 μM), propranolol (1 μM), atropine (1 μM), guanethidine (10 μM) or L-NAME (100 μM) failed to change the inhibition by 5-HT, indicating that the inhibition was due to a direct action of 5-HT on the smooth muscle cells.5-CT, 5-MeOT and 8-OH-DPAT mimicked the inhibitory response of 5-HT, and the rank order of the potency was 5-CT>5-HT>5-MeOT>8-OH-DPAT. On the other hand, oxymethazoline, α-methyl-5-HT, 2-methyl-5-HT, cisapride, BIMU-1, BIMU-8, ergotamine and dihydroergotamine had almost no effect on spontaneous contractions, even at 10–100 μM.Inhibition by 5-HT was not decreased by either pindolol (1 μM), ketanserin (1 μM), tropisetron (10 μM), MDL72222 (1 μM) or GR113808 (10 μM), but was antagonized by the following compounds in a competitive manner (with pA2 values in parentheses): methiothepin (8.05), methysergide (7.92), metergoline (7.4), mianserin (7.08), clozapine (7.06) and spiperone (6.86).Ro 20-1724 (20 μM) and rolipram (10 μM) significantly enhanced the inhibitory response of 5-HT, but neither zaprinast (10 μM) nor dipyridamole (10 μM) altered the response of 5-HT.5-HT (1 nM–1 μM) caused a concentration-dependent accumulation of intracellular cyclic AMP in the circular muscle.From the present results, the 5-HT receptor, which is functionally correlated with the 5-HT7 receptor, mediates the

  13. 5-Hydroxytryptamine Receptor Subtypes and their Modulators with Therapeutic Potentials

    PubMed Central

    Pithadia, Anand B.; Jain, Sunita M.

    2009-01-01

    5-hydroxytryptamine (5-HT) has become one of the most investigated and complex biogenic amines. The main receptors and their subtypes, e.g., 5-HTI (5-HT1A, 5-HT1B, 5-HTID, 5-HTIE and 5-HT1F), 5-HT2 (5-HT2A, 5-HT2B and 5-HT2C), 5-HT3, 5-HT4, 5-HT5 (5-HT5A, 5-HT5B), 5-HT6 and 5-HT7 have been identified. Specific drugs which are capable of either selectively stimulating or inhibiting these receptor subtypes are being designed. This has generated therapeutic potentials of 5-HT receptor modulators in a variety of disease conditions. Conditions where 5-HT receptor modulators have established their use with distinct efficacy and advantages include migraine, anxiety, psychosis, obesity and cancer therapy-induced vomiting by cytotoxic drugs and radiation. Discovery of 5-HT, its biosynthesis, metabolism, physiological role and the potential of 5-HT receptor modulators in various nervous, cardiovascular and gastrointestinal tract disorders, bone growth and micturition have been discussed in this article. Keywords 5-hydroxytryptamine (5-HT) receptors; Modulators; Biogenic amines PMID:22505971

  14. Pharmacological properties of phenyldiguanide and other amidine derivatives in relation to those of 5-hydroxytryptamine

    PubMed Central

    Fastier, F. N.; McDowall, M. A.; Waal, Hendrieka

    1959-01-01

    Cats in which the coronary and allied chemoreflexes could not be obtained with small intravenous doses of 5-hydroxytryptamine were insensitive also to phenyldiguanide. In cats which responded to phenyldiguanide with reflex falls of blood pressure and heart rate, abolished by vagotomy, the effects of graded doses (5 to 150 μg./kg.) of phenyldiguanide bore a striking resemblance to those produced initially by 5-hydroxytryptamine in somewhat smaller doses. Differences in the cardiovascular responses to the two drugs are attributed to additional (non-reflex) actions of 5-hydroxytryptamine. The reflex actions of both drugs were blocked reversibly also by 2-naphthylguanidine (500 μg.). Certain other drugs (bufotenine, procaine, S-decylisothiourea) antagonized the depressor action of phenyldiguanide as well as the reflex depressor action of 5-hydroxytryptamine. Like 5-hydroxytryptamine, phenyldiguanide and certain other amidine derivatives caused pain when applied to the base of blisters in human subjects. Unlike 5-hydroxytryptamine, phenyldiguanide did not constrict perfused rat blood vessels or increase the tone of the rat fundal strip preparation of Vane (1957). Phenyldiguanide did not affect the sensitivity of these smooth muscle preparations to 5-hydroxytryptamine, but other amidine derivatives proved to be moderately strong antagonists of the vasoconstrictor actions of 5-hydroxytryptamine and of adrenaline. Unlike 5-hydroxytryptamine, phenyldiguanide did not produce gastric haemorrhage in the mouse. Phenyldiguanide did not prolong chloral hydrate sleeping time in mice by the same mechanism as did 5-hydroxytryptamine. Phenyldiguanide was not highly toxic to mice (LD50 being 240 mg./kg.). It is concluded that phenyldiguanide and certain other amidine derivatives act on sensory receptors which respond to 5-hydroxytryptamine, but that they show little pharmacological resemblance to 5-hydroxytryptamine in other respects. PMID:13821683

  15. Lysergic acid diethylamide: role in conversion of plasma tryptophan to brain serotonin (5-hydroxytryptamine).

    PubMed

    Lin, R C; Ngai, S H; Costa, E

    1969-10-10

    Injections of D-lysergic acid diethylamide decrease the turnover rate of 5-hydroxytryptamine of rat brain, as measured from the conversion of (14)C-tryptophan into (14)C-5-hydroxytryptamine. The 2-bromolysergic acid diethylamide given in doses fivefold greater than those of lysergic acid diethylamide fails to change the rate of (14)C-tryptophan conversion into (14)C-5-hydroxytryptamine. The effect of D-lysergic acid diethylamide is discussed with regard to its action on brain serotonergic neurons and its psychotomimetic effects.

  16. 5-hydroxytryptamine induced relaxation in the pig urinary bladder neck

    PubMed Central

    Recio, Paz; Barahona, María Victoria; Orensanz, Luis M; Bustamante, Salvador; Martínez, Ana Cristina; Benedito, Sara; García-Sacristán, Albino; Prieto, Dolores; Hernández, Medardo

    2009-01-01

    Background and purpose 5-Hydroxytryptamine (5-HT) is one of the inhibitory mediators in the urinary bladder outlet region. Here we investigated mechanisms involved in 5-HT-induced relaxations of the pig bladder neck. Experimental approach Urothelium-denuded strips of pig bladder were mounted in organ baths for isometric force recordings of responses to 5-HT and electrical field stimulation (EFS). Key results After phenylephrine-induced contraction, 5-HT and 5-HT receptor agonists concentration-dependently relaxed the preparations, with the potency order: 5-carboxamidotryptamine (5-CT) > 5-HT = RS67333 > (±)-8-hydroxy-2-dipropylaminotetralinhydrobromide > m-chlorophenylbiguanide > α-methyl-5-HT > ergotamine. 5-HT and 5-CT relaxations were reduced by the 5-HT7 receptor antagonist (2R)-1-[(3-hydroxyphenyl)sulphonyl]-2-[2-(4-methyl-1-piperidinyl)ethyl]pyrrolidine hydrochloride and potentiated by (S)-N-tert-butyl-3-(4-(2-methoxyphenyl)-piperazin-1-yl)-2-phenylpropanamide dihydrochloride (WAY 100135) and cyanopindolol, 5-HT1A and 5-HT1A/1B receptor antagonists respectively. Inhibitors of 5-HT1B/1D, 5-HT2, 5-HT2B/2C, 5-HT3, 5-HT4, 5-HT5A and 5-HT6 receptors failed to modify 5-HT responses. Blockade of monoamine oxidase A/B, noradrenergic neurotransmission, α-adrenoceptors, muscarinic and purinergic receptors, nitric oxide synthase, guanylate cyclase and prostanoid synthesis did not alter relaxations to 5-HT. Inhibitors of Ca2+-activated K+ and ATP-dependent K+ channels failed to modify 5-HT responses but blockade of neuronal voltage-gated Na+-, Ca2+-and voltage-gated K+ (Kv)-channels potentiated these relaxations. Adenylyl cyclase activation and cAMP-dependent protein kinase (PKA) inhibition potentiated and reduced, respectively, 5-HT-induced responses. Under non-adrenergic, non-cholinergic, non-nitrergic conditions, EFS induced neurogenic, frequency-dependent, relaxations which were resistant to WAY 100135 and cyanopindolol. Conclusions and implications 5-HT relaxed

  17. Naftopidil inhibits 5-hydroxytryptamine-induced bladder contraction in rats.

    PubMed

    Sakai, Takumi; Kasahara, Ken-ichi; Tomita, Ken-ichi; Ikegaki, Ichiro; Kuriyama, Hiroshi

    2013-01-30

    Naftopidil is an α(1D) and α(1A) subtype-selective α(1)-adrenoceptor antagonist that has been used to treat lower urinary tract symptoms of benign prostatic hyperplasia. In this study, we investigated the effects of naftopidil on 5-hydroxytryptamine (5-HT)-induced rat bladder contraction (10(-8)-10(-4) M). Naftopidil (0.3, 1, and 3 μM) inhibited 5-HT-induced bladder contraction in a concentration-dependent manner. On the other hand, other α(1)-adrenoceptor antagonists, tamsulosin, silodosin or prazosin, did not inhibit 5-HT-induced bladder contraction. The 5-HT-induced bladder contraction was inhibited by both ketanserin and 4-(4-fluoronaphthalen-1-yl)-6-propan-2-ylpyrimidin-2-amine (RS127445), serotonin 5-HT(2A) and 5-HT(2B) receptor antagonists, respectively. In addition, 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) and α-methyl-5-HT, 5-HT(2A) and 5-HT(2) receptor agonists, respectively, induced bladder contraction. The 5-HT-induced bladder contraction was not inhibited by N-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]-N-pyridin-2-yl-cyclohexanecarboxamide (WAY-100635), [1-[2[(methylsulfonyl)amino]ethyl]-4-piperidinyl]methyl-1-methyl-1H-indole-3-carboxylate (GR113808) or (R)-3-[2-[2-(4-methylpiperidin-1-yl)ethyl]pyrrolidine-1-sulphonyl]phenol (SB269970), 5-HT(1A), 5-HT(4) and 5-HT(7) receptor antagonists, respectively. Naftopidil inhibited both the 5-HT(2A) and 5-HT(2) receptor agonists-induced bladder contractions. Naftopidil binds to the human 5-HT(2A) and 5-HT(2B) receptors with pKi values of 6.55 and 7.82, respectively. These results suggest that naftopidil inhibits 5-HT-induced bladder contraction via blockade of the 5-HT(2A) and 5-HT(2B) receptors in rats. Furthermore, 5-HT-induced bladder contraction was enhanced in bladder strips obtained from bladder outlet obstructed rats, with this contraction inhibited by naftopidil. The beneficial effects of naftopidil on storage symptoms such as urinary frequency and nocturia in patients with benign

  18. Differential interactions of indolealkylamines with 5-hydroxytryptamine receptor subtypes.

    PubMed

    McKenna, D J; Repke, D B; Lo, L; Peroutka, S J

    1990-03-01

    Affinities of drugs for 21 indolealkylamine derivatives, some with putative hallucinogenic activity, were determined at 5-HT1A, 5-HT2A and 5-HT2B recognition sites, using radioligand competition studies. Nearly all of the derivatives displayed greatest potency for the 5-HT2A receptor, labelled by [125I]R-(-)DOI in the cortex of the rat. Most derivatives displayed 2-10 times lower affinity at the HT2B receptor labelled by [3H]ketanserin in bovine cortex. Derivatives lacking ring substituents displayed lower affinities for all of the recognition sites, compared to derivatives substituted in the 4- or 5-position of the indole ring. The 4-hydroxylated derivatives displayed 25-380-fold selectivity for the 5-HT2A site, vs the 5-HT1A site, while the 5-substituted derivatives displayed approximately equal potency at the 5-HT1A and 5-HT2A sites. Affinity of all the compounds at the 5-HT2B site was greater than 300 nM. The 6-substituted derivatives displayed greater than micromolar affinities for all of the 5-HT recognition sites examined. The size of the N,N-dialkyl substituent was a secondary determinant of affinity, with groups larger than N,N-diisopropyl resulting in a marked reduction in affinity at both the 5-HT2A and 5-HT1A recognition sites. This study demonstrated that hallucinogenic 4-hydroxy-indolealkylamines, like psychotomimetic phenylisopropylamines, bind potently and selectively to the 5-HT2A recognition site, labelled by [125I]R-(-)DOI. This provides further evidence indicating that this recently described subtype of the 5-HT2 receptor may partially mediate the action of hallucinogenic agents.

  19. Effect of Y-25130, a selective 5-hydroxytryptamine3 receptor antagonist, on gastric emptying in mice.

    PubMed

    Haga, K; Asano, K; Inaba, K; Morimoto, Y; Setoguchi, M

    1994-01-01

    The effect of Y-25130 on gastric emptying of nutrient test meals (solid chow) was examined in mice. In a dose range of 0.01-1 mg/kg, p.o., Y-25130 significantly accelerated gastric emptying of solid meals in a dose-dependent manner, at an ED30 of 0.021 mg/kg. Other 5-hydroxytryptamine3 receptor antagonists and prokinetic agents having 5-hydroxytryptamine3 receptor antagonistic properties accelerated the emptying of solid meals in the following rank order of potency: Y-25130 = granisetron > or = tropisetron > ondansetron > cisapride > metoclopramide. The acceleration of the gastric emptying showed a good correlation with the antagonistic potencies of these compounds on 5-hydroxytryptamine3 receptors, determined by the inhibition test of the von Bezold-Jarisch reflex in anesthetized rats (r2 = 0.99). Domperidone (1 and 10 mg/kg, p.o.) and trimebutine (10 and 100 mg/kg, p.o.) failed to increase the rate of emptying from the stomach. Cisplatin (30 mg/kg, i.p.), a chemotherapeutic agent, significantly delayed the gastric emptying of solid meals, and Y-25130 (0.1-1 mg/kg, p.o.) prevented such a delay in emptying in a dose-dependent manner. These results suggest that Y-25130 accelerates the gastric emptying in mice by antagonism of the 5-hydroxytryptamine3 receptor. PMID:7625886

  20. Release of ( sup 14 C)5-hydroxytryptamine from human platelets by red wine

    SciTech Connect

    Jarman, J.; Glover, V.; Sandler, M. )

    1991-01-01

    Red wine, at a final dilution of 1/50, caused released of ({sup 14}C)5-hydroxytryptamine (5-HT) from preloaded platelets, an effect which was not observed with any white wines or beers tested. Since 5-HT, is probably released from body stores during migraine attacks and red wine is known to provoke migraine episodes in susceptible individuals, release of 5-HT, possibly from central stores, could represent a plausible mechanism for its mode of action.

  1. High-level stable expression of recombinant 5-HT1A 5-hydroxytryptamine receptors in Chinese hamster ovary cells.

    PubMed Central

    Newman-Tancredi, A; Wootton, R; Strange, P G

    1992-01-01

    The human 5-hydroxytryptamine 5-HT1A receptor gene was transfected into Chinese hamster ovary cells. A series of recombinant monoclonal cell lines expressing the receptor were isolated and the properties of one cell line that expressed receptors at a high level (2.8 pmol/mg) were studied in detail. In ligand binding assays with the selective 5-HT1A receptor agonist 2-(NN-di[3H]propylamino)-8-hydroxy-1,2,3,4-tetrahydronaphthalene ([3H]8-OH-DPAT) only a single class of saturable high-affinity binding sites was detected, with a pharmacological profile in competition experiments essentially identical to that of the 5-HT1A receptor of bovine hippocampus. [3H]8-OH-DPAT binding to the recombinant cell membranes was inhibited by GTP, showing that the receptors in the transfected cells couple to G-proteins. A series of 5-hydroxytryptamine agonists inhibited forskolin-stimulated adenylate cyclase activity in the cells and, despite the high level of receptor expression, their apparent efficacies were similar to those observed for inhibition of adenylate cyclase in brain. This recombinant cell line provides a complete model system for studying the 5-HT1A receptor and its transmembrane signalling system. The recombinant cells can also be grown in suspension culture for long periods but, whereas 5-HT1A receptor numbers and receptor regulation by guanine nucleotides are maintained in suspension-grown cells, the inhibition of adenylate cyclase by the 5-HT1A receptor is gradually lost. Images Fig. 1. PMID:1386736

  2. Interactions between acetylcholine, 5-hydroxytryptamine, nicotine and morphine on isolated rabbit atria

    PubMed Central

    Chittal, S. M.; Dadkar, N. K.; Gaitondé, B. B.

    1968-01-01

    1. The effects of 5-hydroxytryptamine (5-HT) and morphine on the responses to acetylcholine and nicotine of isolated rabbit atria were studied. 2. 5-Hydroxytryptamine (10 μg/ml.) and morphine (20 μg/ml.) blocked the negative chronotropic and inotropic actions of acetylcholine. 3. Nicotine (20 μg/ml.) produced stimulation of the atria, which was blocked by dichlorisoprenaline, morphine, 5-HT, bretylium and hemicholinium. Hemicholinium block was reversed by choline. 4. In reserpinized preparations, nicotine produced inhibition of atria and this action was also blocked by atropine, 5-HT and morphine. Inhibition induced by nicotine was potentiated by physostigmine. 5. 5-Hydroxytryptamine (20 μg/ml.) produced stimulation of atria. This was blocked by bretylium and reduced by hemicholinium. Hemicholinium block was reversed by choline. 6. It is concluded that 5-HT in low concentrations acts as a weak agonist at the cholinoceptive receptors and therefore blocks the action of acetylcholine. Furthermore, nicotine and larger doses of 5-HT have actions on ganglionic structures and liberate acetylcholine, which in turn releases catecholamines. PMID:4386371

  3. Interactions between acetylcholine, 5-hydroxytryptamine, nicotine and morphine on isolated rabbit atria.

    PubMed

    Chittal, S M; Dadkar, N K; Gaitondé, B B

    1968-09-01

    1. The effects of 5-hydroxytryptamine (5-HT) and morphine on the responses to acetylcholine and nicotine of isolated rabbit atria were studied.2. 5-Hydroxytryptamine (10 mug/ml.) and morphine (20 mug/ml.) blocked the negative chronotropic and inotropic actions of acetylcholine.3. Nicotine (20 mug/ml.) produced stimulation of the atria, which was blocked by dichlorisoprenaline, morphine, 5-HT, bretylium and hemicholinium. Hemicholinium block was reversed by choline.4. In reserpinized preparations, nicotine produced inhibition of atria and this action was also blocked by atropine, 5-HT and morphine. Inhibition induced by nicotine was potentiated by physostigmine.5. 5-Hydroxytryptamine (20 mug/ml.) produced stimulation of atria. This was blocked by bretylium and reduced by hemicholinium. Hemicholinium block was reversed by choline.6. It is concluded that 5-HT in low concentrations acts as a weak agonist at the cholinoceptive receptors and therefore blocks the action of acetylcholine. Furthermore, nicotine and larger doses of 5-HT have actions on ganglionic structures and liberate acetylcholine, which in turn releases catecholamines.

  4. The effect of atropine on the activation of 5-hydroxytryptamine3 channels in rat nodose ganglion neurons.

    PubMed

    Fan, P; Weight, F F

    1994-10-01

    It has been suggested that changes in brain 5-hydroxytryptamine3 receptor function may contribute to some behavior disorders, such as anxiety, schizophrenia and drug abuse. We are using the whole-cell version of the patch-clamp technique to study the function of 5-hydroxytryptamine3 channels in neurons freshly dissociated from rat nodose ganglion. In these cells, 5-hydroxytryptamine elicits an inward current over the concentration range of 0.25-100 microM (EC50 = 2.62 microM) by activating 5-hydroxytryptamine3 receptors. The muscarinic cholinergic antagonist atropine reduced the amplitude of 5-hydroxytryptamine activated inward current in a concentration-dependent manner. Other muscarinic antagonists, scopolamine, dexetimide, the M1 muscarinic receptor antagonist pirenzepine, the M2 receptor antagonist methoctramine and the M3 receptor antagonist 4-DAMP methiodide also inhibited 5-hydroxytryptamine-induced inward current. Atropine did not appear to change the reversal potential of this current. In the presence of 5 microM atropine, the concentration-response curve for 5-hydroxytryptamine current was shifted to the right in a parallel fashion. The EC50 value for 5-hydroxytryptamine was increased from 2.62 to 8.76 microM. Schild plots of increasing atropine and 5-hydroxytryptamine concentrations revealed a pA2 value of 5.74 for atropine (apparent KD = 1.8 microM). These observations suggest that atropine competitively antagonizes the activation of a receptor for the neurotransmitter serotonin, a novel action of muscarinic antagonists in the nervous system. This effect of atropine may contribute to the clinical symptoms seen in severe atropine intoxication. PMID:7531305

  5. Reversal learning enhanced by lysergic acid diethylamide (LSD): concomitant rise in brain 5-hydroxytryptamine levels.

    PubMed

    King, A R; Martin, I L; Melville, K A

    1974-11-01

    1 Small doses of lysergic acid diethylamide (LSD) (12.5-50 mug/kg) consistently facilitated learning of a brightness discrimination reversal.2 2-Bromo-lysergic acid diethylamide (BOL-148), a structural analogue of LSD, with similar peripheral anti-5-hydroxytrypamine activity but no psychotomimetic properties, had no effect in this learning situation at a similar dose (25 mug/kg).3 LSD, but not BOL-148, caused a small but significant increase in brain 5-hydroxytryptamine levels, but had no effect on the levels of catecholamines in the brain at 25 mug/kg.

  6. Mechanisms of 5-hydroxytryptamine-induced contraction of isolated rat intrapulmonary bronchi.

    PubMed

    Szarek, J L; Zhang, J Z; Gruetter, C A

    1995-12-01

    Previous studies in our laboratory and others suggested that activation of 5-HT2 receptors mediates 5-hydroxytryptamine (5-HT)-induced contraction of airway smooth muscle and that this response is dependent in part on endogenous acetylcholine (ACh). The purpose of the present study was to confirm a role for 5-HT2 receptors and endogenous ACh in 5-HT-induced contraction of rat bronchi. In this study, we examined the effects of 5-HT2 receptor antagonists (ketanserin and LY53857), acetylcholinesterase inhibitors (physostigmine and neostigmine), and a muscarinic receptor alkylating agent [propylbenzilylcholine mustard (PBCM)] on contractile responses evoked by 5-HT and the 5-HT2 receptor agonist, alpha-methyl-5-hydroxytryptamine (alpha-Me-5-HT). Concentration-response curves generated in isolated rat intrapulmonary bronchi in response to 5-HT and alpha-Me-5-HT were superimposable. Inhibition of acetylcholinesterase by physostigmine or neostigmine potentiated contractile responses elicited by 5-HT and alpha-Me-5-HT. Alkylation of muscarinic receptors with PBCM decreased maximal responses elicited by 5-HT or alpha-Me-5-HT in a concentration-dependent manner. Maximum contraction attained with exogenous ACh was decreased by PBCM in a concentration-dependent manner and, at the highest concentration evaluated, ACh-induced contractions were abolished. 5-Hydroxytryptamine-induced contraction was inhibited competitively by low concentrations of the 5-HT2-receptor selective antagonist, ketanserin; higher concentrations abolished contractile responses to the amine. The inhibition of 5-HT-induced contractile responses by another 5-HT2-receptor selective antagonist, LY53857, was non-competitive in nature. Together, the results suggest that 5-HT contracts rat airways directly by activating 5-HT2 receptors located on airway smooth muscle and indirectly by activation of 5-HT2 receptors on parasympathetic nerve endings to cause release of ACh. The potential physiological implication of

  7. Iontophoretic release of acetylcholine, noradrenaline, 5-hydroxytryptamine and D-lysergic acid diethylamide from micropipettes.

    PubMed

    Bradley, P B; Candy, J M

    1970-10-01

    1. The in vitro iontophoretic release of tritium-labelled acetylcholine and 5-hydroxytryptamine from large and small micropipettes and noradrenaline and D-lysergic acid diethylamide from small micropipettes was determined by liquid scintillation counting.2. The release was directly proportional to the electrical charge passed in the range normally used in the iontophoretic study of these compounds. The transport numbers obtained for the large micropipettes were approximately double those with the small micropipettes. A very low transport number was found for D-lysergic acid diethylamide.3. The spontaneous leakage was small and did not vary appreciably with time.4. The iontophoretic release of acetylcholine in vitro agreed with the in vitro measurements.5. The brain-stem tissue concentration of D-lysergic acid diethylamide after intravenous injection into intact and decerebrate cats was determined.

  8. The effect of altered 5-hydroxytryptamine levels on beta-endorphin

    NASA Technical Reports Server (NTRS)

    Soliman, Karam F. A.; Mash, Deborah C.; Walker, Charles A.

    1986-01-01

    The purpose of the present study was to examine the effect of altering the concentration of 5-hydroxytryptamine (5-HT) on beta-endorphin (beta-Ep) content in the hypothalamus, thalamus, and periaqueductal gray (PAG)-rostral pons regions of the rat brain. The selective 5-HT reuptake inhibitor, fluoxetine (10 mg/kg), significantly lowered beta-Ep content in the hypothalamus and the PAG. Parachlorophenylalanine, which inhibits 5-HT synthesis, significantly elevated beta-Ep in all brain parts studied. Intracisternal injections of the neurotoxin 5-prime, 7-prime-dihydroxytryptamine with desmethylimipramine pretreatment significantly increased beta-Ep content in the hypothalamus and the PAG. In adrenalectomized rats, fluoxetine significantly decreased beta-Ep levels in the hypothalamus and increased the levels in the PAG. The results indicate that 5-HT may modulate the levels of brain beta-Ep.

  9. Gene expression profiling analysis of 5-hydroxytryptamine signaling pathway in rat regenerating liver and different types of liver cells.

    PubMed

    Chang, C F; Yang, J; Zhao, W M; Li, Y; Guo, P J; Li, M H; Zhou, Y; Xu, C S

    2015-01-01

    We examined the gene expression profiles of the 5-hydroxytryptamine signaling pathway in the regenerating liver and 8 types of liver cells during rat liver regeneration, and explored expression differences in 5-hydroxytryptamine signaling pathway genes at the level of tissues and cells, as well as the role of the pathway on liver regeneration. Eight types of rat regenerating liver cells were isolated using Percoll density-gradient centrifugation and immunomagnetic bead methods. Rat Genome 230 2.0 Array was used to detect expression changes in 5-hydroxytryptamine signaling pathway genes. The results showed that 26, 47, 8, 21, 16, 19, 22, 27, and 20 genes changed significantly in hepatocytes, biliary epithelial cells, hepatic stellate cells, oval cells, sinusoidal endothelial cells, Kupffer cells, pit cells, dendritic cells, and the regenerating liver, respectively. Synthetic effects of 5-hydroxytryptamine signaling pathway genes in 8 types of liver cells showed that 26 genes were expressed significantly; the expression trends of 10 genes were the same in the regenerating liver, while others were different. Based on the gene expression profiles of the 8 types of liver cells, 5-hydroxytryptamine promoted hepatocyte proliferation through the RAS and STAT3 signaling pathways, proliferation and differentiation of sinusoidal endothelial cells through the STAT3 signaling pathway, and proliferation and apoptosis of pit cells through the AKT3 signaling pathway. There were large differences in genes involved in 5-hydroxytryptamine signaling at the tissue and cellular levels; thus, liver regeneration should be studied in-depth at the cellular level to reveal the molecular mechanism of liver regeneration.

  10. The effect of lysergic acid diethylamide, 5-hydroxytryptamine, and related compounds on the liver fluke, Fasciola hepatica.

    PubMed

    MANSOUR, T E

    1957-12-01

    The rhythmical activity of the liver fluke, Fasciola hepatica, was stimulated by 5-hydroxytryptamine and by lysergic acid diethylamide at very low concentrations. The effect was peripheral and was not mediated through the central ganglion. Other amines also stimulated rhythmical activity, the most potent being the indolamines.Bromolysergic acid diethylamide, and other analogues such as yohimbine, harmine, and dopamine depressed rhythmical movement and antagonized the stimulant action of 5-hydroxytryptamine and lysergic acid diethylamide. Evidence which suggests the presence of tryptamine receptors in the trematode is discussed.

  11. Unsurmountable antagonism of brain 5-hydroxytryptamine2 receptors by (+)-lysergic acid diethylamide and bromo-lysergic acid diethylamide.

    PubMed

    Burris, K D; Sanders-Bush, E

    1992-11-01

    Lysergic acid diethylamide (LSD) and its structural analogue 2-bromo-lysergic acid diethylamide (BOL) act as unsurmountable antagonists of serotonin-elicited contractions in smooth muscle preparations. Two different models, allosteric and kinetic, have been invoked to explain these findings. The present studies investigate the mechanism of antagonism of brain 5-hydroxytryptamine (5HT)2 receptors, utilizing cells transfected with 5HT2 receptor cDNA cloned from rat brain. A proximal cellular response, phosphoinositide hydrolysis, was examined in order to minimize possible postreceptor effects. Even though LSD behaved as a partial agonist and BOL as a pure antagonist, both drugs blocked the effect of serotonin in an unsurmountable manner, i.e., increasing concentrations of serotonin could not overcome the blocking effect of LSD or BOL. Radioligand binding studies showed that preincubation of membranes with either LSD or BOL reduced the density of [3H]ketanserin binding sites, suggesting that the drugs bind tightly to the 5HT2 receptor and are not displaced during the binding assay. Two additional experiments supported this hypothesis. First, the off-rate of [3H] LSD was slow (20 min), relative to that of [3H]ketanserin (approximately 4 min). Second, when the length of incubation with [3H]ketanserin was increased to 60 min, the LSD-induced decrease in Bmax was essentially eliminated. The possibility that LSD and BOL decrease [3H]ketanserin binding by interacting with an allosteric site was rejected, because neither drug altered the rate of dissociation of [3H]ketanserin. The most parsimonious interpretation of these results is that unsurmountable antagonism reflects prolonged occupancy of the receptor by slowly reversible antagonists.

  12. 5-hydroxytryptamine (5-HT) reduces total peripheral resistance during chronic infusion: direct arterial mesenteric relaxation is not involved

    PubMed Central

    2012-01-01

    Serotonin (5-hydroxytryptamine; 5-HT) delivered over 1 week results in a sustained fall in blood pressure in the sham and deoxycorticosterone acetate (DOCA)-salt rat. We hypothesized 5-HT lowers blood pressure through direct receptor-mediated vascular relaxation. In vivo, 5-HT reduced mean arterial pressure (MAP), increased heart rate, stroke volume, cardiac index, and reduced total peripheral resistance during a 1 week infusion of 5-HT (25 µg/kg/min) in the normotensive Sprague Dawley rat. The mesenteric vasculature was chosen as an ideal candidate for the site of 5-HT receptor mediated vascular relaxation given the high percentage of cardiac output the site receives. Real-time RT-PCR demonstrated that mRNA transcripts for the 5-HT2B, 5-HT1B, and 5-HT7 receptors are present in sham and DOCA-salt superior mesenteric arteries. Immunohistochemistry and Western blot validated the presence of the 5-HT2B, 5- HT1B and 5-HT7 receptor protein in sham and DOCA-salt superior mesenteric artery. Isometric contractile force was measured in endothelium-intact superior mesenteric artery and mesenteric resistance arteries in which the contractile 5- HT2A receptor was antagonized. Maximum concentrations of BW-723C86 (5- HT2B agonist), CP 93129 (5-HT1B agonist) or LP-44 (5-HT7 agonist) did not relax the superior mesenteric artery from DOCA-salt rats vs. vehicle. Additionally, 5-HT (10–9 M to 10–5 M) did not cause relaxation in either contracted mesenteric resistance arteries or superior mesenteric arteries from normotensive Sprague- Dawley rats. Thus, although 5-HT receptors known to mediate vascular relaxation are present in the superior mesenteric artery, they are not functional, and are therefore not likely involved in a 5-HT-induced fall in total peripheral resistance and MAP. PMID:22559843

  13. 5-HT1 agonists reduce 5-hydroxytryptamine release in rat hippocampus in vivo as determined by brain microdialysis.

    PubMed Central

    Sharp, T.; Bramwell, S. R.; Grahame-Smith, D. G.

    1989-01-01

    1. An intracerebral perfusion method, brain microdialysis, was used to assess changes of 5-hydroxytryptamine (5-HT) release in the ventral hippocampus of the chloral hydrate-anaesthetized rat in response to systemic administration of a variety of 5-HT1 receptor agonists. 2. A stable output of reliably detectable endogenous 5-HT was measured in dialysates collected from ventral hippocampus with the 5-HT reuptake inhibitor, citalopram, present in the perfusion medium. 3. Under these conditions the putative 5-HT1A agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) caused a dose-dependent (5-250 micrograms kg-1, s.c.) reduction of 5-HT in hippocampal dialysates. 4. Similarly, the putative 5-HT1A agonists gepirone (5 mg kg-1, s.c.), ipsapirone (5 mg kg-1, s.c.) and buspirone (5 mg kg-1, s.c.) markedly reduced levels of 5-HT in hippocampal perfusates whereas their common metabolite 1-(2-pyrimidinyl) piperazine (5 mg kg-1, s.c.), which does not bind to central 5-HT1A recognition sites, had no effect. 5. 5-Methoxy-3-(1,2,3,6-tetrahydro-4-pyridinyl)-1H-indole (RU 24969), a drug with reported high affinity for brain 5-HT1B binding sites, also produced a dose-dependent (0.25-5 mg kg-1, s.c.) decrease of hippocampal 5-HT output. 6. These data are direct biochemical evidence that systemically administered putative 5-HT1A and 5-HT1B agonists markedly inhibit 5-HT release in rat ventral hippocampus in vivo. PMID:2466516

  14. Repeated exposure of rats to the convulsant agent flurothyl enhances 5-hydroxytryptamine- and dopamine-mediated behavioural responses

    PubMed Central

    Green, A.R.

    1978-01-01

    1 Rats were convulsed once daily for 7 days by exposure to the inhalant convulsant agent, flurothyl (Indoklon, bis (2,2,2-trifluouroethyl)ether). Twenty four hours after the final convulsion the rats were injected with tranylcypromine (20 mg/kg) followed 30 min later by L-DOPA (50 mg/kg), a procedure which increases brain dopamine concentrations. The flurothyl-treated rats showed a greater locomotor activity response than rats that had not been convulsed. 2 This enhanced response appears to be due to increased postsynaptic dopamine receptor sensitivity since flurothyl-treated rats also showed enhanced locomotor responses to methamphetamine (2 mg/kg) and apomorphine (2 mg/kg). 3 Enhanced 5-hydroxytryptamine-induced activity responses following administration of tranylcypromine (20 mg/kg) and L-tryptophan (50 mg/kg) were also seen 24 h after the last of 10 daily flurothyl-induced convulsions. 4 The increased 5-hydroxytryptamine response also appears to be due to increased postsynaptic sensitivity since the flurothyl-treated rats showed increased hyperactivity following administration of tranylcypromine (20 mg/kg) and the suggested 5-hydroxytryptamine agonist, 5-methoxy N,N-dimethyltryptamine (2 mg/kg). 5 No change in the brain concentration of 5-hydroxytryptamine, 5-hydroxyindoleacetic acid, tryptophan, dopamine or noradrenaline was observed 24 h after the last of 10 daily flurothyl-induced convulsions, compared to untreated rats. The rate of 5-hydroxytryptamine accumulation after tranylcypromine/L-tryptophan treatment and of dopamine and noradrenaline accumulation after tranylcypromine/L-DOPA treatment was similar in both groups. 6 Repeated flurothyl convulsion has the same effects on these behavioural tests as repeated electroconvulsive shock. Since both treatments have been used successfully to treat depression, it is suggested that the mechanism of action of electroconvulsive therapy may be by increasing postsynaptic responses to the monoamine neurotransmitters

  15. Moderate differences in circulating corticosterone alter receptor-mediated regulation of 5-hydroxytryptamine neuronal activity.

    PubMed

    Judge, Sarah J; Ingram, Colin D; Gartside, Sarah E

    2004-12-01

    Circulating glucocorticoid levels vary with stress and psychiatric illness and play a potentially important role in regulating transmitter systems that regulate mood. To determine whether chronic variation in corticosterone levels within the normal diurnal range altered the control of 5-hydroxytryptamine (5-HT) neuronal activity, male rats were adrenalectomized and implanted with either a 2% or 70% corticosterone/cholesterol pellet (100 mg). Two weeks later, the regulation of 5-HT neuronal activity in the dorsal raphe nucleus was studied by in vitro electrophysiology. At this time, serum corticosterone levels approximated the low-point (2%) and mid-point (70%) of the diurnal range. The excitatory response of 5-HT neurones to the alpha1-adrenoceptor agonist phenylephrine (1-11 microM) was significantly greater in the 2% group compared to the 70% group. By contrast, the inhibitory response to 5-HT (10-50 microM) was significantly lower in the 2% group compared to the 70% group. Thus, chronic variation in circulating corticosterone over a narrow part of the normal diurnal range causes a shift in the balance of positive and negative regulation of 5-HT neurones, with increased alpha 1-adrenoceptor-mediated excitation and reduced 5-HT-mediated autoinhibition at lower corticosterone levels. This shift would have a major impact on control of 5-HT neuronal activity. PMID:15582914

  16. Inhibition of the serotonin (5-hydroxytryptamine) transporter reduces bone accrual during growth.

    PubMed

    Warden, Stuart J; Robling, Alexander G; Sanders, Megan S; Bliziotes, Michael M; Turner, Charles H

    2005-02-01

    Selective serotonin-reuptake inhibitors (SSRIs) antagonize the serotonin (5-hydroxytryptamine) transporter (5-HTT), and are frequently prescribed to children and adolescents to treat depression. However, recent findings of functional serotonergic pathways in bone cells and preliminary clinical evidence demonstrating detrimental effects of SSRIs on bone growth have raised questions regarding the effects of these drugs on the growing skeleton. The current work investigated the impact of 5-HTT inhibition on the skeleton in: 1) mice with a null mutation in the gene encoding for the 5-HTT; and 2) growing mice treated with a SSRI. In both models, 5-HTT inhibition had significant detrimental effects on bone mineral accrual. 5-HTT null mutant mice had a consistent skeletal phenotype of reduced mass, altered architecture, and inferior mechanical properties, whereas bone mineral accrual was impaired in growing mice treated with a SSRI. These phenotypes resulted from a reduction in bone formation without an increase in bone resorption and were not influenced by effects on skeletal mechanosensitivity or serum biochemistries. These findings indicate a role for the 5-HTT in the regulation of bone accrual in the growing skeleton and point to a need for further research into the prescription of SSRIs to children and adolescents.

  17. Radioimmunoassay of serotonin (5-hydroxytryptamine) in cerebrospinal fluid, plasma, and serum

    SciTech Connect

    Engbaek, F.; Voldby, B

    1982-04-01

    A direct radioimmunoassay is described for serotonin (5-hydroxytryptamine) in cerebrospinal fluid, platelet-poor plasma, and serum. Antisera in rabbits was raised against serotonin diazotized to a conjugate of bovine albumin and D,L-p-aminophenylalanine. Polyethylene glycol, alone or in combination with anti-rabbit immunoglobulins, is used to separate bound and unbound tritiated serotonin. The minimum concentration of serotonin detectable is 2 nmol/L in a 200-..mu..L sample. Within-day precision (CV) is 4.3% between-day precision 7.7%. Analytical recoveries of serotonin are 109% and 101% for cerebrospinal fluid and plasma, respectively. Tryptophan, 5-hydroxytryptophan, 5-hydroxyindoleacetic acid, and 5-hydroxytryptophol do not interfere with the assay. However, 5-methoxytryptamine and tryptamine cross react. Of samples of cerebrospinal fluid from patients with disc herniations (n=21) or low-pressure hydrocephalus (n=10), one-third had concentrations of 2-4 nmol/L and two-thirds were below the minimum detectable concentration. The observed range for the concentration of serotonin in plasma of 14 normal subjects was 5-14 nmol/L (mean +/- SD, 9 +/- 3 nmol/L). The observed ranges for serotonin in serum were: for 10 women 520-900 (mean +/- SD: 695 +/- 110) nmol/L and for 10 men 380-680 (520 +/- 94) nmol/L.

  18. Vasoconstrictor responses to 5-hydroxytryptamine in the autoperfused hindquarters of spontaneously hypertensive rats.

    PubMed

    Calama, E; Morán, A; Ortiz de Urbina, A V; Martín, M L; San Román, L

    2004-06-01

    In this work we studied the responses and receptors involved in the effects of intra-arterial 5-hydroxytryptamine (5-HT) in the in situ autoperfused hindquarters of spontaneously hypertensive rats (SHR). Intra-arterial administration of the highest doses (50-1,000 ng/kg) produced a vasoconstrictor effect that was inhibited by ritanserin (a selective 5-HT2 receptor antagonist), SB 206553 (a selective 5-HT(2B/2C) receptor antagonist) and spiperone (a nonspecific 5-HT(1/2A) receptor antagonist), and was mimicked by alpha-methyl-5-HT (a selective 5-HT2 receptor agonist) and m-CPP (a selective 5-HT2C receptor agonist), but not by the intra-arterial administration of BW 723C86, a selective 5HT2B receptor agonist. SB 206553 and spiperone inhibited alpha-methyl-5HT-induced vasoconstriction in the hindquarters of SHR. Our data suggest that the vasoconstrictor response induced by 5-HT in the autoperfused hindquarters of SHR is mainly mediated by the activation of 5-HT2A and 5-HT2C receptors.

  19. Role of 5-hydroxytryptamine in the regulation of brain neuropeptides in normal and diabetic rat.

    PubMed

    Kolta, M G; Soliman, K F; Williams, B B

    1986-01-01

    The effect of 5-hydroxytryptamine (5-HT) alteration on brain dopamine (DA), norepinephrine (NE), beta-endorphin (beta E) and immunoreactive insulin (IRI) was studied in Sprague-Dawley diabetic and control rats. Diabetes was induced using alloxan (45 mg/kg), 15 days prior to sacrificing. Both control and diabetic animals were treated with either p-chlorophenylalanine (PCPA, 300 mg/kg) 3 days prior to sacrificing or fluoxetine (10 mg/kg) twice daily for 3 days. PCPA treatment significantly decreased brain content of 5-HT and 5-hydroxyindole acetic acid (5-HIAA) while it caused significant increase and decrease in brain beta E and insulin levels, respectively, in both normal and diabetic rat. Meanwhile, the administration of fluoxetine resulted in significant increase in brain content of 5-HT, DA, NE and insulin but significant decline of beta E in diabetic and saline control rats. The results of this experiment indicate that 5-HT may be regulating both beta E and insulin regardless of the availability of pancreatic insulin.

  20. Role of 5-hydroxytryptamine in the regulation of brain neuropeptides in normal and diabetic rat

    NASA Technical Reports Server (NTRS)

    Kolta, Malak G.; Williams, Byron B.; Soliman, Karam F. A.

    1986-01-01

    The effect of 5-hydroxytryptamine (5-HT) alteration on brain dopamine (DA), norepinephrine (NE), beta-endorphin (beta-E), and immunoreactive insulin was studied in Sprague-Dawley diabetic and control rats. Diabetes was induced using alloxan (45 mg/kg), 15 days prior to sacrificing. Both control and diabetic animals were treated with either p-chlorophenylalanine (PCPA, 300 mg/kg) three days prior to sacrificing or fluoxetine (10 mg/kg) twice daily for three days. PCPA treatment significantly decreased brain content of 5-HT and 5-hydroxyindolel acetic acid, while it caused significant increase and decrease in brain beta-E and insulin levels, respectively, in both normal and diabetic rat. Meanwhile, the administration of fluoxetine resulted in significant increase in brain content of 5-HT, DA, NE and insulin but significant decline of beta-E in diabetic and saline control rats. The results of this experiment indicate that 5-HT may be regulating both beta-E and insulin regardless of the availability of pancreatic insulin.

  1. Characterization of the 5-hydroxytryptamine receptor which mediates contraction of the human isolated basilar artery.

    PubMed

    Parsons, A A; Whalley, E T

    1989-01-01

    This paper reports part of a study which investigated the identity of the receptor involved in 5-hydroxytryptamine (5-HT) mediated contraction of the human basilar artery in vitro. 5-HT and a variety of 5-HT receptor agonists contracted human isolated basilar artery with a rank order of agonist potency: 5-carboxamidotryptamine greater than 5-HT greater than GR43175 much much greater than 2-methyl-5-HT. The maximum response produced by these agonists differed. The contractile responses to both 5-HT and GR43175 were resistant to antagonism by the 5-HT2 antagonist ketanserin and the 5-HT3 antagonist GR38032, indicating that neither 5-HT nor GR43175 activate 5-HT2 and 5-HT3 receptors in this tissue. In striking contrast, methiothepin (an antagonist at 5-HT1-like receptors) proved a potent antagonist of the contractile actions of both 5-HT and GR43175. Methiothepin did not antagonize the contractile response to the thromboxane-A2 mimetic U-46619. It is concluded that 5-HT and GR43175 contract the human isolated basilar artery by activating 5-HT1-like receptors. It is suggested that the antimigraine action of GR43175 may reflect its ability to constrict certain cranial arteries via 5-HT1-like receptor activation. PMID:2544283

  2. Methotrexate causes a change in intestinal 5-hydroxytryptamine metabolism in rats.

    PubMed

    Takano, Yuho; Machida, Takuji; Obara, Yusuke; Hirano, Megumi; Kudo, Sae; Takagi, Minako; Hamaue, Naoya; Iizuka, Kenji; Hirafuji, Masahiko

    2014-10-01

    The effects of methotrexate on 5-hydroxytryptamine (5-HT) metabolism in the intestinal tissue of rats were investigated during the delayed phase after a single administration. Rats were i.p. injected with methotrexate or with saline as a control, and kaolin and food intakes were measured by an automatic monitoring apparatus. At 96 h after administration, dissected-out ileal tissue was frozen rapidly in liquid nitrogen for further analysis or fixed for immunohistochemical staining. Methotrexate at a dose of 50 mg/kg caused a time-dependent increase in kaolin intake lasting up to 72 h after administration, which returned to the control level at 96 h after administration. This dose of methotrexate caused a gradual decrease in body weight, food intake, and water intake lasting up to 72 h, which approached the control level at 96 h. Methotrexate caused pathologic changes, including a moderate inflammatory response in the ileal tissue and an increase in the number of L-tryptophan hydroxylase (TPH)-expressing cells in the ileal mucosa. Methotrexate also caused a significant increase in 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) content and in TPH1 mRNA expression in the ileal tissues. It had no significant effects on mRNA expression of serotonin transporter, COX-1, or COX-2 or on myeloperoxidase activity. This study demonstrated, for the first time, that methotrexate caused a change in the ileal 5-HT metabolism associated with hyperplasia of mucosal enterochromaffin cells.

  3. Effect of 5-hydroxytryptamine on neurogenic vasoconstriction in the isolated, autoperfused hindquarters of the rat.

    PubMed

    Calama, E; Ortíz de Urbina, A V; Morán, A; Martín, M L; San Román, L

    2005-10-01

    1. In the present study, we analysed the effect of different doses of 5-hydroxytryptamine (5-HT; intravenous infusions of 0.001-40 microg/kg per min) in the autoperfused hindquarters of the rat subjected to electrical stimulation (frequencies of 0.5-20 Hz) of the lumbar chains, investigating the relationship between the adrenergic and serotonergic systems in this vascular bed. 2. Because we observed that 5-HT inhibited the increases in perfusion pressure induced by electrical stimulation of the lumbar chains, we used different agonists and antagonists to analyse the mechanism of action of 5-HT. 3. The effect of 5-HT was inhibited by methiothepin (a non-specific 5-HT receptor antagonist), but not by ritanserin (a selective 5-HT2 receptor antagonist). The effects of 5-HT were mimicked by 5-carboxamidotryptamine (a 5-HT1 receptor agonist) and L-694 247 (a selective 5-HT1D receptor agonist), but not by 8-hydroxy-2-dipropylaminotetralin (a 5-HT1A receptor agonist), CGS-12066B (a 5-HT1B receptor agonist), alpha-methyl-5-HT (a 5-HT2 receptor agonist), 1-(3-chlorophenyl) piperazine (a 5-HT2C receptor agonist) or 1-phenylbiguanide (a 5-HT3 receptor agonist). The selective 5-HT1D/1B receptor antagonist BRL 15572 inhibited the effect of the agonist L-694 247. 4. Our data suggest that 5-HT inhibits the increases in perfusion pressure induced by the electrical stimulation of the lumbar chains, acting on presynaptic 5-HT1D receptors and decreasing the release of noradrenaline from the sympathetic nerves in the hindquarter vascular bed of the rat.

  4. Peptide YY3–36 and 5-Hydroxytryptamine Mediate Emesis Induction by Trichothecene Deoxynivalenol (Vomitoxin)

    PubMed Central

    Pestka, James J.

    2013-01-01

    Deoxynivalenol (DON, vomitoxin), a trichothecene mycotoxin produced by Fusarium sp. that frequently occurs in cereal grains, has been associated with human and animal food poisoning. Although a common hallmark of DON-induced toxicity is the rapid onset of emesis, the mechanisms for this adverse effect are not fully understood. Recently, our laboratory has demonstrated that the mink (Neovison vison) is a suitable small animal model for investigating trichothecene-induced emesis. The goal of this study was to use this model to determine the roles of two gut satiety hormones, peptide YY3–36 (PYY3–36) and cholecystokinin (CCK), and the neurotransmitter 5-hydroxytryptamine (5-HT) in DON-induced emesis. Following ip exposure to DON at 0.1 and 0.25mg/kg bw, emesis induction ensued within 15–30min and then persisted up to 120min. Plasma DON measurement revealed that this emesis period correlated with the rapid distribution and clearance of the toxin. Significant elevations in both plasma PYY3–36 (30–60min) and 5-HT (60min) but not CCK were observed during emesis. Pretreatment with the neuropeptide Y2 receptor antagonist JNJ-31020028 attenuated DON- and PYY-induced emesis, whereas the CCK1 receptor antagonist devezapide did not alter DON’s emetic effects. The 5-HT3 receptor antagonist granisetron completely suppressed induction of vomiting by DON and the 5-HT inducer cisplatin. Granisetron pretreatment also partially blocked PYY3–36-induced emesis, suggesting a potential upstream role for this gut satiety hormone in 5-HT release. Taken together, the results suggest that both PYY3–36 and 5-HT play contributory roles in DON-induced emesis. PMID:23457120

  5. 5-Hydroxytryptamine promotes hepatocellular carcinoma proliferation by influencing β-catenin.

    PubMed

    Fatima, Sarwat; Shi, Xiaoke; Lin, Zesi; Chen, Guo-qing; Pan, Xiao-hua; Wu, Justin Che-Yuen; Ho, John W; Lee, Nikki P; Gao, Hengjun; Zhang, Ge; Lu, Aiping; Bian, Zhao Xiang

    2016-02-01

    5-Hydroxytryptamine (5-HT), a neurotransmitter and vasoactive factor, has been reported to promote proliferation of serum-deprived hepatocellular carcinoma (HCC) cells but the detailed intracellular mechanism is unknown. As Wnt/β-catenin signalling is highly dysregulated in a majority of HCC, this study explored the regulation of Wnt/β-catenin signalling by 5-HT. The expression of various 5-HT receptors was studied by quantitative real-time polymerase chain reaction (qPCR) in HCC cell lines as well as in 33 pairs of HCC tumours and corresponding adjacent non-tumour tissues. Receptors 5-HT1D (21/33, 63.6%), 5-HT2B (12/33, 36.4%) and 5-HT7 (15/33, 45.4%) were overexpressed whereas receptors 5-HT2A (17/33, 51.5%) and 5-HT5 (30/33, 90.1%) were reduced in HCC tumour tissues. In vitro data suggests 5-HT increased total β-catenin, active β-catenin and decreased phosphorylated β-catenin protein levels in serum deprived HuH-7 and HepG2 cells compared to control cells under serum free medium without 5-HT. Activation of Wnt/β-catenin signalling was evidenced by increased expression of β-catenin downstream target genes, Axin2, cyclin D1, dickoppf-1 (DKK1) and glutamine synthetase (GS) by qPCR in serum-deprived HCC cell lines treated with 5-HT. Additionally, biochemical analysis revealed 5-HT disrupted Axin1/β-catenin interaction, a critical step in β-catenin phosphorylation. Increased Wnt/β-catenin activity was attenuated by antagonist of receptor 5-HT7 (SB-258719) in HCC cell lines and patient-derived primary tumour tissues in the presence of 5-HT. SB-258719 also reduced tumour growth in vivo. This study provides evidence of Wnt/β-catenin signalling activation by 5-HT and may represent a potential therapeutic target for hepatocarcinogenesis. PMID:26474915

  6. Preclinical pharmacology and pharmacokinetics of AZD3783, a selective 5-hydroxytryptamine 1B receptor antagonist.

    PubMed

    Zhang, Minli; Zhou, Diansong; Wang, Yi; Maier, Donna L; Widzowski, Daniel V; Sobotka-Briner, Cynthia D; Brockel, Becky J; Potts, William M; Shenvi, Ashok B; Bernstein, Peter R; Pierson, M Edward

    2011-11-01

    The preclinical pharmacology and pharmacokinetic properties of (2R)-6-methoxy-8-(4-methylpiperazin-1-yl)-N-(4-morpholin-4-ylphenyl)chromane-2-carboxamide (AZD3783), a potent 5-hydroxytryptamine 1B (5-HT(1B)) receptor antagonist, were characterized as part of translational pharmacokinetic/pharmacodynamic hypothesis testing in human clinical trials. The affinity of AZD3783 to the 5-HT(1B) receptor was measured in vitro by using membrane preparations containing recombinant human or guinea pig 5-HT(1B) receptors and in native guinea pig brain tissue. In vivo antagonist potency of AZD3783 for the 5HT(1B) receptor was investigated by measuring the blockade of 5-HT(1B) agonist-induced guinea pig hypothermia. The anxiolytic-like potency was assessed using the suppression of separation-induced vocalization in guinea pig pups. The affinity of AZD3783 for human and guinea pig 5-HT(1B) receptor (K(i), 12.5 and 11.1 nM, respectively) was similar to unbound plasma EC(50) values for guinea pig receptor occupancy (11 nM) and reduction of agonist-induced hypothermia (18 nM) in guinea pig. Active doses of AZD3783 in the hypothermia assay were similar to doses that reduced separation-induced vocalization in guinea pig pups. AZD3783 demonstrated favorable pharmacokinetic properties. The predicted pharmacokinetic parameters (total plasma clearance, 6.5 ml/min/kg; steady-state volume of distribution, 6.4 l/kg) were within 2-fold of the values observed in healthy male volunteers after a single 20-mg oral dose. This investigation presents a direct link between AZD3783 in vitro affinity and in vivo receptor occupancy to preclinical disease model efficacy. Together with predicted human pharmacokinetic properties, we have provided a model for the quantitative translational pharmacology of AZD3783 that increases confidence in the optimal human receptor occupancy required for antidepressant and anxiolytic effects in patients.

  7. Receptor mechanisms for 5-hydroxytryptamine (5-HT) in isolated ovine umbilical vein.

    PubMed

    Zhang, L; Dyer, D C

    1990-08-10

    5-Hydroxytryptamine (5-HT) and 2,5-dimethoxy-4-methyl-amphetamine (DOM) produced a concentration-dependent contraction in isolated umbilical veins obtained from fetal lambs within 2 weeks of term. Contractions to 5-HT were antagonized by ketanserin, mianserin and methiothepin with the dissociation constants (KB) being 2.17 +/- 0.36, 1.37 +/- 0.55 and 1.98 +/- 0.48 nM, respectively. The order of potency of serotonergic agonists in this tissue was: DOM greater than 5-HT greater than alpha-methyl-5-HT greater than 1(3-chlorophenyl) piperazine (mCPP) greater than m-trifluoromethyl-phenylpiperazine (TFMPP) greater than 8-hydroxy-dipropylaminotetralin (8-OH-DPAT) = 2-methyl-5-HT. alpha-Methyl-5-HT was a full agonist compared to 5-HT. DOM possessed greater affinity but less efficacy than that of 5-HT. The affinities and efficacies of the other agonists studied were lower than those of 5-HT. Variation in the sensitivity and potency of agonists is primarily due to variations in their affinity for 5-HT receptors. Assessment of receptor occupancy vs. functional response demonstrated very little, if any, receptor reserve for 5-HT receptors in this tissue. Contractile responses to DOM, 8-OH-DPAT, mCPP and 2-methyl-5-HT were effectively blocked by ketanserin. The dissociation constants (KB) of ketanserin against these agonists were as follows: DOM, 2.78 +/- 0.85 nM; 8-OH-DPAT, 3.47 +/- 1.12 nM; mCPP, 1.45 +/- 0.51 nM; 2-methyl-5-HT, 1.99 +/- 0.74 nM. The dissociation constant of MDL 72222 (3-tropanyl-3,5-dichlorobenzoate) vs. 5-HT was 13833 nM. No antagonism by prazosin (10(-7) M) or yohimbine (10(-7) M) of the responses to 5-HT was observed. These results indicate that 5-HT2 receptors are present in the ovine umbilical vein. 5-HT3 receptors were not present in this tissue. Activation of alpha-adrenoceptors was not involved in the contractions to 5-HT.

  8. Characterization of the 5-hydroxytryptamine receptors mediating contraction in the pig isolated intravesical ureter

    PubMed Central

    Hernández, Medardo; Barahona, María Victoria; Simonsen, Ulf; Recio, Paz; Rivera, Luis; Martínez, Ana Cristina; García-Sacristán, Albino; Orensanz, Luis M; Prieto, Dolores

    2003-01-01

    This study was designed to investigate the effect of 5-hydroxytryptamine (5-HT) and to characterize the 5-HT receptors involved in 5-HT responses in the pig intravesical ureter. 5-HT (0.01–10 μM) concentration-dependently increased the tone of intravesical ureteral strips, whereas the increases in phasic contractions were concentration-independent. The 5-HT2 receptor agonist α-methyl 5-HT, mimicked the effect on tone whereas weak or no response was obtained with 5-CT, 8-OH-DPAT, m-chlorophenylbiguanide and RS 67333, 5-HT1, 5-HT1A, 5-HT3 and 5-HT4 receptor agonists, respectively. 5-HT did not induce relaxation of U46619-contracted ureteral preparations. Pargyline (100 μM), a monoaminooxidase A/B activity inhibitor, produced leftward displacements of the concentration-response curves for 5-HT. 5-HT-induced tone was reduced by the 5-HT2 and 5-HT2A receptor antagonists ritanserine (0.1 μM) and spiperone (0.2 μM), respectively. However, 5-HT contraction was not antagonized by cyanopindolol (2 μM), SDZ–SER 082 (1 μM), Y-25130 (1 μM) and GR 113808 (0.1 μM), which are respectively, 5-HT1A/1B, 5-HT2B/2C, 5-HT3, and 5-HT4 selective receptor antagonists. Removal of the urothelium did not modify 5-HT-induced contractions. Blockade of neuronal voltage-activated sodium channels, α-adrenergic receptors and adrenergic neurotransmission with tetrodotoxin (1 μM), phentolamine (0.3 μM) and guanethidine (10 μM), respectively, reduced the contractions to 5-HT. However, physostigmine (1 μM), atropine (0.1 μM) and suramin (30 μM), inhibitors of cholinesterase activity, muscarinic- and purinergic P2-receptors, respectively, failed to modify the contractions to 5-HT. These results suggest that 5-HT increases the tone of the pig intravesical ureter through 5-HT2A receptors located at the smooth muscle. Part of the 5-HT contraction is indirectly mediated via noradrenaline release from sympathetic nerves. PMID:12522083

  9. Multiple microvascular and astroglial 5-hydroxytryptamine receptor subtypes in human brain: molecular and pharmacologic characterization.

    PubMed

    Cohen, Z; Bouchelet, I; Olivier, A; Villemure, J G; Ball, R; Stanimirovic, D B; Hamel, E

    1999-08-01

    Physiologic and anatomic evidence suggest that 5-hydroxytryptamine (5-HT) neurons regulate local cerebral blood flow and blood-brain barrier permeability. To evaluate the possibility that some of these effects occur directly on the blood vessels, molecular and/or pharmacologic approaches were used to assess the presence of 5-HT receptors in human brain microvascular fractions, endothelial and smooth muscle cell cultures, as well as in astroglial cells which intimately associate with intraparenchymal blood vessels. Isolated microvessels and capillaries consistently expressed messages for the h5-HT1B, h5-HT1D, 5-HT1F, 5-HT2A but not 5-HT7 receptors. When their distribution within the vessel wall was studied in more detail, it was found that capillary endothelial cells exhibited mRNA for the h5-HT1D and for the 5-HT7 receptors whereas microvascular smooth muscle cells, in addition to h5-HT1D and 5-HT7, also showed polymerase chain reaction products for h5-HT1B receptors. Expression of 5-HT1F and 5-HT2A receptor mRNAs was never detected in any of the microvascular cell cultures. In contrast, messages for all 5-HT receptors tested were detected in human brain astrocytes with a predominance of the 5-HT2A and 5-HT7 subtypes. In all cultures, sumatriptan inhibited (35-58%, P < .05) the forskolin-stimulated production of cyclic AMP, an effect blocked by the 5-HT1B/1D receptor antagonists GR127935 and GR55562. In contrast, 5-carboxamidotryptamine induced strong increases (> or = 400%, P < .005) in basal cyclic AMP levels that were abolished by mesulergine, a nonselective 5-HT7 receptor antagonist. Only astroglial cells showed a ketanserin-sensitive increase (177%, P < .05) in IP3 formation when exposed to 5-HT. These results show that specific populations of functional 5-HT receptors are differentially distributed within the various cellular compartments of the human cortical microvascular bed, and that human brain astroglial cells are endowed with multiple 5-HT receptors

  10. Anxiogenic-like effects and reduced stereological counting of immunolabelled 5-hydroxytryptamine6 receptors in rat nucleus accumbens by antisense oligonucleotides.

    PubMed

    Otano, A; Frechilla, D; Cobreros, A; Cruz-Orive, L M; Insausti, A; Insausti, R; Hamon, M; Del Rio, J

    1999-01-01

    The physiological role of 5-hydroxytryptamine6 receptors in the central nervous system has not yet been elucidated. The high affinity of various psychotropic drugs for 5-hydroxytryptamine6 receptors has led to the suggestion that this receptor type may be a novel target in neuropsychiatry. We have found that continuous intracerebroventricular administration of a 5-hydroxytryptamine6 receptor antisense oligonucleotide, but not of a missense oligonucleotide, produced an anxiogenic-like response in rats using two different models of anxiety, the social interaction test and the elevated plus-maze. Neither oligonucleotide treatment modified locomotor activity, rectal temperature or food intake, suggesting a low or null neurotoxicity. The effectiveness of the treatment with the designed antisense oligonucleotide to block the synthesis of the protein encoded by the target mRNA was assessed by immunolabelling 5-hydroxytryptamine6 receptors in the nucleus accumbens, where this receptor is highly expressed, using previously characterized specific antibodies. The density of the immunostaining was quantified by means of an unbiased three-dimensional stereologic procedure, which revealed a significant reduction (-25%) in the number of immunolabelled neuronal elements. These results suggest that, in addition to other 5-hydroxytryptamine receptor subtypes, 5-hydroxytryptamine6 receptors in the nucleus accumbens may participate in anxiety-related neurobiological mechanisms.

  11. 5-Hydroxytryptamine receptors mediating vasoconstriction in pulmonary arteries from control and pulmonary hypertensive rats.

    PubMed Central

    MacLean, M. R.; Sweeney, G.; Baird, M.; McCulloch, K. M.; Houslay, M.; Morecroft, I.

    1996-01-01

    1. We investigated 5-hydroxytryptamine (5-HT)-receptor mediated vasoconstriction in the main, first branch and resistance pulmonary arteries removed from control and pulmonary hypertensive rats. Contractile responses to 5-HT, 5-carboxamidotryptamine (5-CT, non-selective 5-HT1 agonist), and sumatriptan (5-HT1D-like receptor agonist) were studied. The effects of methiothepin (non-selective 5-HT1 + 2-receptor antagonist) and ketanserin (5-HT2A receptor antagonist) and GR55562 (a novel selective 5-HT1D receptor antagonist) on 5-HT-mediated responses were also studied. Basal levels of adenosine 3':5'-cyclic monophosphate ([cyclic AMP]i) and guanosine 3':5'-cyclic monophosphate ([cyclic GMP]i) were determined and we assessed the degree of inherent tone in the vessels under study. 2. 5-HT was most potent in the resistance arteries. pEC50 values were 5.6 +/- 0.1, 5.3 +/- 0.1, 5.0 +/- 0.2 in the resistance arteries, pulmonary branch and main pulmonary artery, respectively (n = at least 5 from 5 animals). The sensitivity to, and maximum response of, 5-HT was increased in all the arteries removed from the chronic hypoxic (CH) rats. In CH rats the pEC50 values were 5.9 +/- 0.2, 6.3 +/- 0.2, 6.4 +/- 0.2 and the increase in the maximum response was 35%, 51% and 41% in the resistance arteries, pulmonary branch and main pulmonary artery, respectively. Sumatriptan did not contract any vessel from the control rats whilst 5-CT did contract the resistance arteries. In the CH rats, however, they both contracted the resistance arteries (responses to sumatriptan were small) (pEC50: 5-CT; 5.4 +/- 0.2) and the pulmonary artery branches (pEC50: sumatriptan, 5.4 +/- 0.2; 5-CT, 5.4 +/- 0.2). 5-CT also caused a contraction in the main pulmonary artery (pEC50: 6.0 +/- 0.3). 3. Ketanserin (1 nM-1 microM) caused a competitive antagonism of the 5-HT response in all vessels tested. In control rats, the estimated pKb values for ketanserin in resistance arteries, pulmonary branches and main pulmonary

  12. Regulation of rat cortical 5-hydroxytryptamine2A-receptor mediated electrophysiological responses by repeated daily treatment with electroconvulsive shock or imipramine

    PubMed Central

    Marek, Gerard J.

    2008-01-01

    Down-regulation of 5-hydroxytryptamine2A (5-HT2A) receptors has been a consistent effect induced by most antidepressant drugs. In contrast, electroconvulsive shock (ECS) up-regulates the number of 5-HT2A receptor binding sites. However, the effects of antidepressants on 5-HT2A receptor-mediated responses on identified cells of the cerebral cortex has not been examined. The purpose of the present study was to compare the effects of the tricyclic antidepressant imipramine and ECS on 5-HT2A receptor-mediated electrophysiological responses involving glutamatergic and GABAergic neurotransmission in the rat medial prefrontal cortex (mPFC) and piriform cortex, respectively. The electrophysiological effects of activating 5-HT2A receptors was consistent with 5-HT2A receptor binding regulation for imipramine and ECS except for the mPFC where chronic ECS decreased the potency of 5-HT at a 5-HT2A receptor-mediated response. These findings are consistent with the general hypothesis that chronic antidepressant treatments shift the balance of serotonergic neurotransmission towards inhibitory effects in the cortex. PMID:18294819

  13. Regulation of rat cortical 5-hydroxytryptamine2A receptor-mediated electrophysiological responses by repeated daily treatment with electroconvulsive shock or imipramine.

    PubMed

    Marek, Gerard J

    2008-07-01

    Down-regulation of 5-hydroxytryptamine(2A) (5-HT(2A)) receptors has been a consistent effect induced by most antidepressant drugs. In contrast, electroconvulsive shock (ECS) up-regulates the number of 5-HT(2A) receptor binding sites. However, the effects of antidepressants on 5-HT(2A) receptor-mediated responses on identified cells of the cerebral cortex have not been examined. The purpose of the present study was to compare the effects of the tricyclic antidepressant imipramine and ECS on 5-HT(2A) receptor-mediated electrophysiological responses involving glutamatergic and GABAergic neurotransmission in the rat medial prefrontal cortex (mPFC) and piriform cortex, respectively. The electrophysiological effects of activating 5-HT(2A) receptors were consistent with 5-HT(2A) receptor binding regulation for imipramine and ECS except for the mPFC where chronic ECS decreased the potency of 5-HT at a 5-HT(2A) receptor-mediated response. These findings are consistent with the general hypothesis that chronic antidepressant treatments shift the balance of serotonergic neurotransmission towards inhibitory effects in the cortex.

  14. 5-Hydroxytryptamine 4(a) receptor expressed in Sf9 cells is palmitoylated in an agonist-dependent manner.

    PubMed Central

    Ponimaskin, E G; Schmidt, M F; Heine, M; Bickmeyer, U; Richter, D W

    2001-01-01

    The mouse 5-hydroxytryptamine 4(a) receptor [5-HT(4(a))] was expressed with a baculovirus system in insect cells and analysed for acylation. [(3)H]Palmitic acid was effectively incorporated into 5-HT(4(a)) and label was sensitive to the treatment with reducing agents indicating a thioester-type bond. Analysis of protein-bound fatty acids revealed that 5-HT(4(a)) contains predominantly palmitic acid. Treatment of infected Sf9 (Spodoptera frugiperda) cells with BIMU8 [(endo-N-8-methyl-8-azabicyclo[3.2.1]oct-3-yl)-2,3-dehydro-2-oxo-3-(prop-2-yl)-1H-benzimid-azole-1-carboxamide], a 5-HT(4) receptor-selective agonist, generated a dose-dependent increase in [(3)H]palmitate incorporation into 5-HT(4(a)) with an EC(50) of approx. 10 nM. The change in receptor labelling after stimulation with agonist was receptor-specific and did not result from general metabolic effects. We also used both pulse labelling and pulse-chase labelling to address the dynamics of 5-HT(4(a)) palmitoylation. Incorporation studies revealed that the rate of palmitate incorporation was increased approx. 3-fold after stimulation with agonist. Results of pulse-chase experiments show that activation with BIMU8 promoted the release of radiolabel from 5-HT(4(a)), thereby reducing the levels of receptor-bound palmitate to approximately one-half. Taken together, our results demonstrate that palmitoylation of 5-HT(4(a)) is a reversible process and that stimulation of 5-HT(4(a)) with agonist increases the turnover rate for receptor-bound palmitate. This provides evidence for a regulated cycling of receptor-bound palmitate and suggests a functional role for palmitoylation/depalmitoylation in 5-hydroxytryptamine-mediated signalling. PMID:11171060

  15. Measuring the serotonin uptake site using (/sup 3/H)paroxetine--a new serotonin uptake inhibitor

    SciTech Connect

    Gleiter, C.H.; Nutt, D.J.

    1988-01-01

    Serotonin is an important neurotransmitter that may be involved in ethanol preference and dependence. It is possible to label the serotonin uptake site in brain using the tricyclic antidepressant imipramine, but this also binds to other sites. We have used the new high-affinity uptake blocker paroxetine to define binding to this site and report it to have advantages over imipramine as a ligand.

  16. ( sup 3 H)-DOB(4-bromo-2,5-dimethoxyphenylisopropylamine) and ( sup 3 H) ketanserin label two affinity states of the cloned human 5-hydroxytryptamine2 receptor

    SciTech Connect

    Branchek, T.; Adham, N.; Macchi, M.; Kao, H.T.; Hartig, P.R. )

    1990-11-01

    The binding properties of the 5-hydroxytryptamine2 (5-HT2) receptor have been the subject of much interest and debate in recent years. The hallucinogenic amphetamine derivative 4-bromo-2,5-dimethoxyphenylisopropylamine (DOB) has been shown to bind to a small number of binding sites with properties very similar to (3H)ketanserin-labeled 5-HT2 receptors, but with much higher agonist affinities. Some researchers have interpreted this as evidence for the existence of a new subtype of 5-HT2 receptor (termed 5-HT2A), whereas others have interpreted these data as indicative of agonist high affinity and agonist low affinity states for the 5-HT2 receptor. In this investigation, a cDNA clone encoding the serotonin 5-HT2 receptor was transiently transfected into monkey kidney Cos-7 cells and stably transfected into mouse fibroblast L-M(TK-) cells. In both systems, expression of this single serotonin receptor cDNA led to the appearance of both (3H)DOB and (3H)ketanserin binding sites with properties that matched their binding characteristics in mammalian brain homogenates. Addition of guanosine 5'-(beta, gamma-imido) triphosphate (Gpp(NH)p) to this system caused a rightward shift and steepening of agonist competition curves for (3H) ketanserin binding, converting a two-site binding curve to a single low affinity binding state. Gpp(NH)p addition also caused a 50% decrease in the number of high affinity (3H)DOB binding sites, with no change in the dissociation constant of the remaining high affinity states. These data on a single human 5-HT2 receptor cDNA expressed in two different transfection host cells indicate that (3H)DOB and (3H)ketanserin binding reside on the same gene product, apparently interacting with agonist and antagonist conformations of a single human 5-HT2 receptor protein.

  17. Tianeptine: 5-HT uptake sites and 5-HT(1-7) receptors modulate memory formation in an autoshaping Pavlovian/instrumental task.

    PubMed

    Meneses, Alfredo

    2002-05-01

    Recent studies using invertebrate and mammal species have revealed that, endogenous serotonin (5-hydroxytryptamine, 5-HT) modulates cognitive processes, particularly learning and memory, though, at present, it is unclear the manner, where, and how long 5-HT systems are involved. Hence in this work, an attempt was made to study the effects of 5-HT endogenous on memory formation, using a 5-HT uptake facilitator (tianeptine) and, selective 5-HT(1-7) receptor antagonists to determine whether 5-HT uptake sites and which 5-HT receptors are involved, respectively. Results showed that post-training tianeptine injection enhanced memory consolidation in an autoshaping Pavlovian/instrumental learning task, which has been useful to detect changes on memory formation elicited by drugs or aging. On interaction experiments, ketanserin (5-HT(1D/2A/2C) antagonist) slightly enhanced tianeptine effects, while WAY 100635 (5-HT(1A) antagonist), SB-224289 (5-HT(1B) inverse agonist), SB-200646 (5-HT(2B/2C) antagonist), ondansetron (5-HT(3) antagonist), GR 127487 (5-HT(4) antagonist), Ro 04-6790 (5-HT(6) antagonist), DR 4004 (5-HT(7) antagonist), or fluoxetine (an inhibitor of 5-HT reuptake) blocked the facilitatory tianeptine effect. Notably, together tianeptine and Ro 04-6790 impaired learning consolidation. Moreover, 5-HT depletion completely reversed the tianeptine effect. Tianeptine also normalized an impaired memory elicited by scopolamine (an antimuscarinic) or dizocilpine (non-competitive glutamatergic antagonist), while partially reversed that induced by TFMPP (5-HT(1B/1D/2A-2C/7) agonist/antagonist). Finally, tianeptine-fluoxetine coadministration had no effect on learning consolidation; nevertheless, administration of an acetylcholinesterase inhibitor, phenserine, potentiated subeffective tianeptine or fluoxetine doses. Collectively, these data confirmed that endogenously 5-HT modulates, via uptake sites and 5-HT(1-7) receptors, memory consolidation, and are consistent with the

  18. 5-Hydroxytryptamine (serotonin)2A receptors in rat anterior cingulate cortex mediate the discriminative stimulus properties of d-lysergic acid diethylamide.

    PubMed

    Gresch, Paul J; Barrett, Robert J; Sanders-Bush, Elaine; Smith, Randy L

    2007-02-01

    d-Lysergic acid diethylamide (LSD), an indoleamine hallucinogen, produces profound alterations in mood, thought, and perception in humans. The brain site(s) that mediates the effects of LSD is currently unknown. In this study, we combine the drug discrimination paradigm with intracerebral microinjections to investigate the anatomical localization of the discriminative stimulus of LSD in rats. Based on our previous findings, we targeted the anterior cingulate cortex (ACC) to test its involvement in mediating the discriminative stimulus properties of LSD. Rats were trained to discriminate systemically administered LSD (0.085 mg/kg s.c.) from saline. Following acquisition of the discrimination, bilateral cannulae were implanted into the ACC (AP, +1.2 mm; ML, +/-1.0 mm; DV, -2.0 mm relative to bregma). Rats were tested for their ability to discriminate varying doses of locally infused LSD (0.1875, 0.375, and 0.75 microg/side) or artificial cerebrospinal fluid (n = 3-7). LSD locally infused into ACC dose-dependently substituted for systemically administered LSD, with 0.75 microg/side LSD substituting completely (89% correct). Systemic administration of the selective 5-hydroxytryptamine (serotonin) (5-HT)(2A) receptor antagonist R-(+)-alpha-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenylethyl)]-4-piperidine-methanol (M100907; 0.4 mg/kg) blocked the discriminative cue of LSD (0.375 microg/side) infused into ACC (from 68 to 16% drug lever responding). Furthermore, M100907 (0.5 microg/microl/side) locally infused into ACC completely blocked the stimulus effects of systemic LSD (0.04 mg/kg; from 80 to 12% on the LSD lever). Taken together, these data indicate that 5-HT(2A) receptors in the ACC are a primary target mediating the discriminative stimulus properties of LSD.

  19. Genetic variation in 5-hydroxytryptamine transporter expression causes adaptive changes in 5-HT₄ receptor levels.

    PubMed

    Jennings, Katie Ann; Licht, Cecilie Löe; Bruce, Aynsley; Lesch, Klaus-Peter; Knudsen, Gitte Moos; Sharp, Trevor

    2012-09-01

    Genetic variation in 5-HT transporter (5-HTT) expression is a key risk factor for psychiatric disorder and has been linked to changes in the expression of certain 5-HT receptor subtypes. This study investigated the effect of variation in 5-HTT expression on 5-HT₄ receptor levels in both 5-HTT knockout (KO) and overexpressing (OE) mice using autoradiography with the selective 5-HT₄ receptor radioligand, [³H]SB207145. Compared to wild-type (5-HTT⁺/⁺) controls, homozygous 5-HTT KO mice (5-HTT⁻/⁻) had reduced 5-HT₄ receptor binding site density in all brain regions examined (35-65% of 5-HTT⁺/⁺). In contrast, the density of 5-HT₄ receptor binding sites was not significantly different between heterozygous 5-HTT KO mice (5-HTT⁻/⁺) and 5-HTT⁺/⁺ mice. The 5-HT synthesis inhibitor p-chlorophenylalanine (250 mg/kg twice daily for 3 d) abolished the difference in 5-HT₄ binding between 5-HTT⁻/⁻ and 5-HTT⁺/⁺ mice in all brain regions. Compared to wild-type (WT) littermate controls, 5-HTT OE mice had increased 5-HT₄ binding density across all brain regions, except amygdala (118-164% of WT) and this difference between genotypes was reduced by the 5-HTT inhibitor, fluoxetine (20 mg/kg twice daily, 3 d). Together, these findings suggest that variation in 5-HTT expression causes adaptive changes in 5-HT₄ receptor levels which are directly linked to alterations in 5-HT availability.

  20. Structure and function of the third intracellular loop of the 5-hydroxytryptamine2A receptor: the third intracellular loop is alpha-helical and binds purified arrestins.

    PubMed

    Gelber, E I; Kroeze, W K; Willins, D L; Gray, J A; Sinar, C A; Hyde, E G; Gurevich, V; Benovic, J; Roth, B L

    1999-05-01

    Understanding the precise structure and function of the intracellular domains of G protein-coupled receptors is essential for understanding how receptors are regulated, and how they transduce their signals from the extracellular milieu to intracellular sites. To understand better the structure and function of the intracellular domain of the 5-hydroxytryptamine2A (5-HT2A) receptor, a model G(alpha)q-coupled receptor, we overexpressed and purified to homogeneity the entire third intracellular loop (i3) of the 5-HT2A receptor, a region previously implicated in G-protein coupling. Circular dichroism spectroscopy of the purified i3 protein was consistent with alpha-helical and beta-loop, -turn, and -sheet structure. Using random peptide phage libraries, we identified several arrestin-like sequences as i3-interacting peptides. We subsequently found that all three known arrestins (beta-arrestin, arrestin-3, and visual arrestin) bound specifically to fusion proteins encoding the i3 loop of the 5-HT(2A) receptor. Competition binding studies with synthetic and recombinant peptides showed that the middle portion of the i3 loop, and not the extreme N and C termini, was likely to be involved in i3-arrestin interactions. Dual-label immunofluorescence confocal microscopic studies of rat cortex indicated that many cortical pyramidal neurons coexpressed arrestins (beta-arrestin or arrestin-3) and 5-HT2A receptors, particularly in intracellular vesicles. Our results demonstrate (a) that the i3 loop of the 5-HT2A receptor represents a structurally ordered domain composed of alpha-helical and beta-loop, -turn, and -sheet regions, (b) that this loop interacts with arrestins in vitro, and is hence active, and (c) that arrestins are colocalized with 5-HT2A receptors in vivo.

  1. 5-Hydroxytryptamine 1A and 2B serotonin receptors in neurite outgrowth: involvement of early growth response protein 1.

    PubMed

    Anelli, Tonino; Cardarelli, Silvia; Ori, Michela; Nardi, Irma; Biagioni, Stefano; Poiana, Giancarlo

    2013-01-01

    Neurotransmitters play important roles in neurogenesis; in particular, acetylcholine and serotonin may regulate neurite elongation. Acetylcholine may also activate transcription factors such as early growth response protein 1 (EGR-1), which plays a role in neurite extension. N18TG2 neuroblastoma cells (which do not produce neurotransmitters and constitutively express muscarinic acetylcholine receptors) were transfected with constructs containing the cDNA for choline acetyltransferase, 5-hydroxytryptamine 1A (5-HT1A) and 5-HT2B serotonin receptors to study acetylcholine and serotonin interplay in neurite outgrowth. 5-HT1A receptor stimulation causes a decrease in EGR-1 levels and inhibition of neurite outgrowth; 5-HT2B stimulation, however, has no effect. Muscarinic cholinergic stimulation, on the other end, increases EGR-1 levels and fiber outgrowth. Inhibition of EGR-1 binding reduces fiber outgrowth activity. When both cholinergic and 5-HT1A receptors are stimulated, fiber outgrowth is restored; therefore, acetylcholine counterbalances the inhibitory effect of serotonin on neurite outgrowth. These results suggest that EGR-1 plays a role in the interplay of acetylcholine and serotonin in the regulation of neurite extension during development. PMID:24158140

  2. Long-lasting neuroprotective effect of sildenafil against 3,4-methylenedioxymethamphetamine- induced 5-hydroxytryptamine deficits in the rat brain.

    PubMed

    Puerta, Elena; Barros-Miñones, Lucia; Hervias, Isabel; Gomez-Rodriguez, Violeta; Orejana, Lourdes; Pizarro, Neus; de la Torre, Rafael; Jordán, Joaquín; Aguirre, Norberto

    2012-02-01

    Sildenafil, given shortly before 3,4-methylenedioxymethamphetamine (MDMA), affords protection against 5-hydroxytryptamine (5-HT) depletions caused by this amphetamine derivative by an acute preconditioning-like mechanism. Because acute and delayed preconditionings do not share the same mechanisms, we investigated whether sildenafil would also protect the 5-HT system of the rat if given 24 hr before MDMA. For this, MDMA (3 × 5 mg/kg i.p., every 2 hr) was administered to rats previously treated with sildenafil (8 mg/kg p.o.). One week later, 5-HT content and 5-HT transporter density were measured in the striatum, frontal cortex, and hippocampus of the rats. Our findings indicate that sildenafil afforded significant protection against MDMA-induced 5-HT deficits without altering the acute hyperthermic response to MDMA or its metabolic disposition. Sildenafil promoted ERK1/2 activation an effect that was paralleled by an increase in MnSOD expression that persisted 24 hr later. In addition, superoxide and superoxide-derived oxidants, shown by ethidium fluorescence, increased after the last MDMA injection, an effect that was prevented by sildenafil pretreatment. Similarly, MDMA increased nitrotyrosine concentration in the hippocampus, an effect not shown by sildenafil-pretreated rats. In conclusion, our data demonstrate that sildenafil produces a significant, long-lasting neuroprotective effect against MDMA-induced 5-HT deficits. This effect is apparently mediated by an increased expression of MnSOD and a subsequent reduced susceptibility to the oxidative stress caused by MDMA.

  3. Identification of 5-Hydroxytryptamine-Producing Cells by Detection of Fluorescence in Paraffin-Embedded Tissue Sections

    PubMed Central

    Kaneko, Y.; Onda, N.; Watanabe, Y.; Shibutani, M.

    2016-01-01

    5-Hydroxytryptamine (5-HT) produced by enterochromaffin (EC) cells is an important enteric mucosal signaling ligand and has been implicated in several gastrointestinal diseases, including inflammatory bowel disease and functional disorders such as irritable bowel syndrome. The present study reports a new, simple and rapid visualization method of 5-HT-producing EC cells utilizing detection of fluorescence in paraffin-embedded tissue sections after formalin fixation. In human samples, there was a high incidence of fluorescence+ cells in the 5-HT+ cells in the pyloric, small intestinal and colonic glands, while co-localization was lacking between fluorescence+ and gastrin+ cells in the pyloric and small intestinal glands. Fluorescence+ EC cells were detected in the colon of mice and rats. Fluorescence+ cells were also observed in 5-HT+ β cells in the pancreatic islets of Langerhans in pregnant mice, while non-pregnant mouse pancreatic islet cells showed no 5-HT immunoreactivity or fluorescence. These results suggest that fluorescence+ cells are identical to 5-HT+ cells, and the source of fluorescence may be 5-HT itself or molecules related to its synthesis or degradation. This fluorescence signal detection method may be applicable for monitoring of inflammatory status of inflammatory bowel diseases in both the experimental and clinical settings. PMID:27734992

  4. Role of 5-hydroxytryptamine 1B (5-HT1B) receptors in the regulation of ethanol intake in rodents

    PubMed Central

    Sari, Youssef

    2012-01-01

    Evidence indicates that the serotonergic system is important in mediating dependence on and craving for alcohol. Among serotonin receptors, 5-hydroxytryptamine 1B (5-HT1B) receptors have been associated with drug abuse including alcohol. In this review, the neurocircuitry involving 5-HT1B receptors in central reward brain regions related to alcohol intake are discussed in detail. Emphasis has been placed on the pharmacological manipulations of 5-HT1B receptor-mediated alcohol intake. Furthermore, 5-HT1B auto- and hetero-receptors regulate alcohol intake through the regulatory mechanism involving release of 5-HT, gamma-aminobutyric acid (GABA), dopamine, and glutamate is evaluated. Thus, interactions between 5-HT1B receptors and these neurotransmitter systems are suggested to modulate alcohol-drinking behavior. This review on the role of 5-HT1B receptors in neurotransmitter release and consequent alcohol intake provides important information about the potential therapeutic role of 5-HT1B receptors for the treatment of alcohol dependence. PMID:23118018

  5. Effects of morphine, physostigmine and raphe nuclei stimulation on 5-hydroxytryptamine release from the cerebral cortex of the cat.

    PubMed Central

    Aiello-Malmberg, P; Bartolini, A; Bartolini, R; Galli, A

    1979-01-01

    1. The release of 5-hydroxytryptamine (5-HT) from the cerebral cortex and caudate nucleus of brainstem-transected cats and from the cerebral cortex of rats anaesthetized with urethane was determined by radioenzymatic and biological assay. 2. The stimulation of nucleus linearis intermedius of raphe doubles the basal 5-HT release in the caudate nucleus and increases it 3 fold in the cerebral cortex. The effects of the electrical stimulation of the raphe are potentiated by chlorimipramine. 3. Brain 5-HT release is greatly increased by morphine hydrochloride (6 mg/kg i.v.) and by physostigmine (100 microgram/kg i.v.), but not by DL-DOPA (50 mg/kg i.v.). 4. It is suggested that the 5-HT releasing action of physostigmine can contribute to some of its pharmacological effects such as the analgesic effect so far attributed exclusively to its indirect cholinomimetic activity. 5. The 5-HT releasing action of physostigmine seems unrelated to its anticholinesterase activity. PMID:435680

  6. 5-Hydroxytryptamine 1A and 2B serotonin receptors in neurite outgrowth: involvement of early growth response protein 1.

    PubMed

    Anelli, Tonino; Cardarelli, Silvia; Ori, Michela; Nardi, Irma; Biagioni, Stefano; Poiana, Giancarlo

    2013-01-01

    Neurotransmitters play important roles in neurogenesis; in particular, acetylcholine and serotonin may regulate neurite elongation. Acetylcholine may also activate transcription factors such as early growth response protein 1 (EGR-1), which plays a role in neurite extension. N18TG2 neuroblastoma cells (which do not produce neurotransmitters and constitutively express muscarinic acetylcholine receptors) were transfected with constructs containing the cDNA for choline acetyltransferase, 5-hydroxytryptamine 1A (5-HT1A) and 5-HT2B serotonin receptors to study acetylcholine and serotonin interplay in neurite outgrowth. 5-HT1A receptor stimulation causes a decrease in EGR-1 levels and inhibition of neurite outgrowth; 5-HT2B stimulation, however, has no effect. Muscarinic cholinergic stimulation, on the other end, increases EGR-1 levels and fiber outgrowth. Inhibition of EGR-1 binding reduces fiber outgrowth activity. When both cholinergic and 5-HT1A receptors are stimulated, fiber outgrowth is restored; therefore, acetylcholine counterbalances the inhibitory effect of serotonin on neurite outgrowth. These results suggest that EGR-1 plays a role in the interplay of acetylcholine and serotonin in the regulation of neurite extension during development.

  7. Characterisation of human 5-hydroxytryptamine2A and 5-hydroxytryptamine2C receptors expressed in the human neuroblastoma cell line SH-SY5Y: comparative stimulation by hallucinogenic drugs.

    PubMed

    Newton, R A; Phipps, S L; Flanigan, T P; Newberry, N R; Carey, J E; Kumar, C; McDonald, B; Chen, C; Elliott, J M

    1996-12-01

    Stable transfection of the human neuroblastoma cell line SH-SY5Y with the human 5-hydroxytryptamine2A (5-HT2A) or 5-HT2C receptor cDNA produced cell lines demonstrating ligand affinities that correlated closely with those for the corresponding endogenous receptors in human frontal cortex and choroid plexus, respectively. Stimulation of the recombinant receptors by 5-HT induced phosphoinositide hydrolysis with higher potency but lower efficacy at the 5-HT2C receptor (pEC50 = 7.80 +/- 0.06) compared with the 5-HT2A receptor (pEC50 = 7.30 +/- 0.08). Activation of the 5-HT2A receptor caused a transient fourfold increase in intracellular Ca2+ concentration. Whole-cell recordings of cells clamped at -50 mV demonstrated a small inward current (2 pA) in response to 10 microM 5-HT for both receptors. There were no differences in potency or efficacy of phosphoinositide hydrolysis among four hallucinogenic [d-lysergic acid diethylamide (LSD), 1-(4-iodo-2,5-dimethoxyphenyl)-2-aminopropane (DOI), 5-methoxy-N,N-dimethyltryptamine, and mescaline] and three nonhallucinogenic drugs (m-chlorophenylpiperazine, quipazine, and ergotamine). Comparison of equipotent doses producing 20% of the maximal response induced by 5-HT revealed selective activation of the 5-HT2A receptor by LSD and to a lesser degree by DOI, mescaline, and ergotamine. Quipazine and 5-methoxy-N,N-dimethyltryptamine were relatively nonselective, whereas m-chlorophenylpiperazine selectively activated the 5-HT2C receptor. It is unlikely therefore that hallucinosis is mediated primarily by activity at the 5-HT2C receptor, whereas activity at the 5-HT2A receptor may represent an important but not unique mechanism associated with hallucinogenic drug action.

  8. Reduced sensitivity to both positive and negative reinforcement in mice over-expressing the 5-hydroxytryptamine transporter.

    PubMed

    Line, Samantha J; Barkus, Chris; Rawlings, Nancy; Jennings, Katie; McHugh, Stephen; Sharp, Trevor; Bannerman, David M

    2014-12-01

    The 5-hydroxytryptamine (5-HT) transporter (5-HTT) is believed to play a key role in both normal and pathological psychological states. Much previous data suggest that the s allele of the polymorphic regulatory region of the 5-HTT gene promoter is associated with reduced 5-HTT expression and vulnerability to psychiatric disorders, including anxiety and depression. In comparison, the l allele, which increases 5-HTT expression, is generally considered protective. However, recent data link this allele to both abnormal 5-HT signalling and psychopathic traits. Here, we studied the processing of aversive and rewarding cues in transgenic mice that over-express the 5-HTT (5-HTTOE mice). Compared with wild-type mice, 5-HTTOE mice froze less in response to both a tone that had previously been paired with footshock, and the conditioning context. In addition, on a decision-making T-maze task, 5-HTTOE mice displayed reduced preference for a larger, delayed reward and increased preference for a smaller, immediate reward, suggesting increased impulsiveness compared with wild-type mice. However, further inspection of the data revealed that 5-HTTOE mice displayed a relative insensitivity to reward magnitude, irrespective of delay. In contrast, 5-HTTOE mice appeared normal on tests of spatial working and reference memory, which required an absolute choice between options associated with either reward or no reward. Overall, the present findings suggest that 5-HTT over-expression results in a reduced sensitivity to both positive and negative reinforcers. Thus, these data show that increased 5-HTT expression has some maladaptive effects, supporting recent suggestions that l allele homozygosity may be a potential risk factor for disabling psychiatric traits.

  9. Treadmill exercise alleviates stress-induced impairment of social interaction through 5-hydroxytryptamine 1A receptor activation in rats

    PubMed Central

    Kim, Tae-Woon; Lim, Baek-Vin; Kim, Kijeong; Seo, Jin-Hee; Kim, Chang-Ju

    2015-01-01

    Brain-derived neurotrophic factor (BDNF) and its receptors tyrosine kinase B (trkB), and cyclic adenosine monophosphate response element binding protein (CREB) have been suggested as the neurobiological risk factors causing depressive disorder. Serotonin (5-hydroxytryptamine, 5-HT) plays an important role in the pathogenesis of depression. We in-vestigated the effect of treadmill exercise on social interaction in relation with BDNF and 5-HT expressions following stress in rats. Stress was induced by applying inescapable 0.2 mA electric foot shock to the rats for 7 days. The rats in the exercise groups were forced to run on a motorized treadmill for 30 min once a day for 4 weeks. Social interaction test and western blot for BDNF, TrkB, pCREB, and 5-HT1A in the hippocampus were performed. The results indicate that the spend time with unfamiliar partner was decreased by stress, in contrast, treadmill exercise increased the spending time in the stress-induced rats. Expressions of BDNF, TrkB, and pCREB were decreased by stress, in contrast, treadmill exercise enhanced expressions of BDNF, TrkB, and pCREB in the stress-induced rats. In addition, 5-HT1A receptor expression was de-creased by stress, in contrast, treadmill exercise enhanced 5-HT1A expression in the stress-induced rats. In the present study, treadmill exercise alleviated stress-induced social interaction impairment through enhancing hippocampal plasticity and serotonergic function in the hippocampus. These effects of treadmill exercise are achieved through 5-HT1A receptor activation. PMID:26331133

  10. 5-Hydroxytryptamine-induced vasodilator responses in the hindquarters of the anaesthetized rat, involve beta2-adrenoceptors.

    PubMed

    Calama, E; García, M; Jarque, M J; Morán, A; Martín, M L; San Román, L

    2003-10-01

    These studies were conducted to examine the role of the vasoactive mediators nitric oxide (NO) and adrenaline (epinephrine) in the serotonin (5-hydroxytryptamine; 5-HT)-induced vasodilator response in the hindquarter vascular bed of anaesthetized rats. Intra-arterial administration of doses of 5-HT in the range 0.12-25 ng kg(-1) produced a dose-independent vasodilator effect in the hindquarters. The selective 5-HT(1D/1B) receptor agonist, L-694,247 at intra-arterial doses of 0.0012-1000 ng kg(-1), as well as adrenaline (at doses of 0.05-50 ng kg(-1) i.a.), mimicked the dose-independent vasodilator effect induced by intra-arterial administration of 5-HT. Intravenous pre-treatment with the selective beta2-receptor antagonist ICI 118,551 (0.5 mg kg(-1)) blocked the vasodilator effect of 5-HT, adrenaline and L-694,247. Additionally, the inhibitor of NO synthase NG-nitro-L-arginine (L-NAME) (at a dose of 10 mg kg(-1) i.v.) blocked the vasodilator action of acetylcholine 300-3000 ng kg(-1)) but did not modify 5-HT-induced vasodilatation. The vasodilator effect produced by intra-arterial administration of 5-HT in the hindquarters was significantly inhibited both 30 min after denervation of the lumbar sympathetic chains and 1 h after bilateral adrenalectomy. Our data suggest that in the in-situ autoperfused hindquarters of the rat 5-HT-induced vasodilatation is mediated by a local 5-HT(1D) or 5-HT(1D/1B) activation, which in turn mediates the adrenal release of adrenaline, which then produces beta2-activation and vasodilatation.

  11. Treadmill exercise alleviates stress-induced impairment of social interaction through 5-hydroxytryptamine 1A receptor activation in rats.

    PubMed

    Kim, Tae-Woon; Lim, Baek-Vin; Kim, Kijeong; Seo, Jin-Hee; Kim, Chang-Ju

    2015-08-01

    Brain-derived neurotrophic factor (BDNF) and its receptors tyrosine kinase B (trkB), and cyclic adenosine monophosphate response element binding protein (CREB) have been suggested as the neurobiological risk factors causing depressive disorder. Serotonin (5-hydroxytryptamine, 5-HT) plays an important role in the pathogenesis of depression. We in-vestigated the effect of treadmill exercise on social interaction in relation with BDNF and 5-HT expressions following stress in rats. Stress was induced by applying inescapable 0.2 mA electric foot shock to the rats for 7 days. The rats in the exercise groups were forced to run on a motorized treadmill for 30 min once a day for 4 weeks. Social interaction test and western blot for BDNF, TrkB, pCREB, and 5-HT1A in the hippocampus were performed. The results indicate that the spend time with unfamiliar partner was decreased by stress, in contrast, treadmill exercise increased the spending time in the stress-induced rats. Expressions of BDNF, TrkB, and pCREB were decreased by stress, in contrast, treadmill exercise enhanced expressions of BDNF, TrkB, and pCREB in the stress-induced rats. In addition, 5-HT1A receptor expression was de-creased by stress, in contrast, treadmill exercise enhanced 5-HT1A expression in the stress-induced rats. In the present study, treadmill exercise alleviated stress-induced social interaction impairment through enhancing hippocampal plasticity and serotonergic function in the hippocampus. These effects of treadmill exercise are achieved through 5-HT1A receptor activation.

  12. Effects of chlorphentermine and phentermine on the pulmonary disposition of 5-hydroxytryptamine in the rat in vivo

    SciTech Connect

    Morita, T.; Mehendale, H.M.

    1983-06-01

    This study was designed to examine whether chlorphentermine (CP) affects pulmonary disposition of 5-hydroxytryptamine (5-HT) in rat in vivo. Further, the effects of CP were compared with those of phentermine (P), the nonchlorinated congener. The right jugular vein and left carotid artery of male Sprague-Dawley rats were cannulated and fresh saline solution containing 150 micrograms indocyanine green and a mixture of labeled and unlabeled 5-HT was injected into the jugular vein, and arterial blood samples were collected for 20 s. In order to compare the effect of CP and P on pulmonary disposition of 5-HT, 2.6 nmol (/sup 14/C)-5-HT was employed for in vivo single-pass experiments. Each animal was used for 2 in vivo single-pass experiments. After the first experiment, which served as a control, animals received an indicated dose of CP or P, to commence the second ''drug-treated'' in vivo experiment. Pulmonary clearance of 5-HT was inhibited by prior administration of CP (1 mg/kg) by 42%, whereas at the highest dose (20 mg/kg) P inhibited 5-HT clearance by only 25%. Pulmonary accumulation of CP was greater than P at higher doses, and the inhibition of 5-HT clearance correlated with the pulmonary accumulation of these drugs. In addition to the in vivo demonstration of the CP inhibition of pulmonary clearance of 5-HT in the rat, these studies also demonstrate a higher affinity of the lung tissue for CP than for P and a greater propensity for the impairment of pulmonary 5-HT clearance.

  13. Assessment of 5-hydroxytryptamine efflux in rat brain during a mild, moderate and severe serotonin-toxicity syndrome.

    PubMed

    Zhang, Gongliang; Krishnamoorthy, Swapna; Ma, Zhiyuan; Vukovich, Nick P; Huang, Xupei; Tao, Rui

    2009-08-01

    Serotonin (5-hydroxytryptamine; 5-HT)-toxicity syndrome, an iatrogenic brain disorder induced by excessive efflux of 5-HT, has received much attention because of increasing incidents of serotonergic antidepressants. However, the neural mechanism by which extracellular 5-HT is elevated to a toxic level for the syndrome remains to be determined. The goal of the present study was to test the hypothesis that extracellular 5-HT is composed of two component effluxes responsible for distinct aspects of the syndrome. The first set of experiments was to characterize the syndrome by measuring changes in neuromuscular signs, body-core temperature and mortality rate. Our results indicate that the syndrome severity can be categorized into mild, moderate and severe levels. The second set of experiments was to determine a threshold of extracellular 5-HT for induction of each level of the syndrome. Our results demonstrate that there were an 11-fold increase in the mild syndrome and an over 55-fold increase in the severe syndrome. In the last series of experiments, the excessive increases in 5-HT were pharmacologically separated into primary and secondary component effluxes with the 5-HT2A receptor antagonists cyproheptadine and ketanserin and NMDA receptor antagonist (+)-MK-801. Our results suggest that the primary component efflux was caused by direct drug effects on 5-HT biosynthetic and metabolic pathways and secondary efflux ascribed to indirect drug effect on a positive-feedback circuit involving 5-HT2A and NMDA receptors. In summary, the primary efflux could be an initial cause for the induction of the syndrome while the secondary efflux might involve deterioration of the syndrome.

  14. Pharmacological activity of (-)-discretamine, a novel vascular alpha-adrenoceptor and 5-hydroxytryptamine receptor antagonist, isolated from Fissistigma glaucescens.

    PubMed Central

    Ko, F. N.; Yu, S. M.; Su, M. J.; Wu, Y. C.; Teng, C. M.

    1993-01-01

    1. The pharmacological activity of (-)-discretamine, isolated from Fissistigma glaucescens, was determined in rat isolated thoracic aorta, cardiac tissues and ventricular myocytes and guinea-pig isolated trachea. 2. (-)-Discretamine was found to be an alpha 1-adrenoceptor blocking agent in rat thoracic aorta as revealed by its competitive antagonism of noradrenaline (pA2 = 7.20 +/- 0.10)- or phenylephrine (pA2 = 7.60 +/- 0.09)-induced vasoconstriction. It was as potent as phentolamine (pA2 = 7.51 +/- 0.10), but was more potent than yohimbine (pA2 = 6.18 +/- 0.06). Removal of endothelium significantly increased the antagonistic potency of (-)-discretamine on noradrenaline (pA2 = 7.52 +/- 0.09)- or phenylephrine (pA2 = 7.90 +/- 0.09)-induced vasoconstriction. 3. (-)-Discretamine was also an alpha 2-adrenoceptor blocking agent (pA2 = 6.30 +/- 0.15) and a 5-hydroxytryptamine antagonist (pA2 = 6.87 +/- 0.06), both in rat aorta denuded of endothelium. 4. (-)-Discretamine protected alpha-adrenoceptors from alkylation by the irreversible blocking agent, phenoxybenzamine. 5. [3H]-inositol monophosphate formation caused by noradrenaline (3 microM) in rat thoracic aorta was suppressed by (-)-discretamine (10 and 30 microM) and prazosin (3 microM). 6. A high concentration of (-)-discretamine (30 microM) did not affect the contraction induced by the thromboxane receptor agonist U-46619, prostaglandin F2 alpha (PGF2 alpha), angiotensin II, high K+ or endothelin in rat aorta denuded of endothelium. Neither cyclic AMP nor cyclic GMP content of rat thoracic aorta was changed by (-)-discretamine.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7902181

  15. Parallel functional activity profiling reveals valvulopathogens are potent 5-hydroxytryptamine(2B) receptor agonists: implications for drug safety assessment.

    PubMed

    Huang, Xi-Ping; Setola, Vincent; Yadav, Prem N; Allen, John A; Rogan, Sarah C; Hanson, Bonnie J; Revankar, Chetana; Robers, Matt; Doucette, Chris; Roth, Bryan L

    2009-10-01

    Drug-induced valvular heart disease (VHD) is a serious side effect of a few medications, including some that are on the market. Pharmacological studies of VHD-associated medications (e.g., fenfluramine, pergolide, methysergide, and cabergoline) have revealed that they and/or their metabolites are potent 5-hydroxytryptamine(2B) (5-HT(2B)) receptor agonists. We have shown that activation of 5-HT(2B) receptors on human heart valve interstitial cells in vitro induces a proliferative response reminiscent of the fibrosis that typifies VHD. To identify current or future drugs that might induce VHD, we screened approximately 2200 U.S. Food and Drug Administration (FDA)-approved or investigational medications to identify 5-HT(2B) receptor agonists, using calcium-based high-throughput screening. Of these 2200 compounds, 27 were 5-HT(2B) receptor agonists (hits); 14 of these had previously been identified as 5-HT(2B) receptor agonists, including seven bona fide valvulopathogens. Six of the hits (guanfacine, quinidine, xylometazoline, oxymetazoline, fenoldopam, and ropinirole) are approved medications. Twenty-three of the hits were then "functionally profiled" (i.e., assayed in parallel for 5-HT(2B) receptor agonism using multiple readouts to test for functional selectivity). In these assays, the known valvulopathogens were efficacious at concentrations as low as 30 nM, whereas the other compounds were less so. Hierarchical clustering analysis of the pEC(50) data revealed that ropinirole (which is not associated with valvulopathy) was clearly segregated from known valvulopathogens. Taken together, our data demonstrate that patterns of 5-HT(2B) receptor functional selectivity might be useful for identifying compounds likely to induce valvular heart disease. PMID:19570945

  16. Reduced sensitivity to both positive and negative reinforcement in mice over-expressing the 5-hydroxytryptamine transporter.

    PubMed

    Line, Samantha J; Barkus, Chris; Rawlings, Nancy; Jennings, Katie; McHugh, Stephen; Sharp, Trevor; Bannerman, David M

    2014-12-01

    The 5-hydroxytryptamine (5-HT) transporter (5-HTT) is believed to play a key role in both normal and pathological psychological states. Much previous data suggest that the s allele of the polymorphic regulatory region of the 5-HTT gene promoter is associated with reduced 5-HTT expression and vulnerability to psychiatric disorders, including anxiety and depression. In comparison, the l allele, which increases 5-HTT expression, is generally considered protective. However, recent data link this allele to both abnormal 5-HT signalling and psychopathic traits. Here, we studied the processing of aversive and rewarding cues in transgenic mice that over-express the 5-HTT (5-HTTOE mice). Compared with wild-type mice, 5-HTTOE mice froze less in response to both a tone that had previously been paired with footshock, and the conditioning context. In addition, on a decision-making T-maze task, 5-HTTOE mice displayed reduced preference for a larger, delayed reward and increased preference for a smaller, immediate reward, suggesting increased impulsiveness compared with wild-type mice. However, further inspection of the data revealed that 5-HTTOE mice displayed a relative insensitivity to reward magnitude, irrespective of delay. In contrast, 5-HTTOE mice appeared normal on tests of spatial working and reference memory, which required an absolute choice between options associated with either reward or no reward. Overall, the present findings suggest that 5-HTT over-expression results in a reduced sensitivity to both positive and negative reinforcers. Thus, these data show that increased 5-HTT expression has some maladaptive effects, supporting recent suggestions that l allele homozygosity may be a potential risk factor for disabling psychiatric traits. PMID:25283165

  17. Serotonin 5-hydroxytryptamine(2A) receptor activation suppresses tumor necrosis factor-alpha-induced inflammation with extraordinary potency.

    PubMed

    Yu, Bangning; Becnel, Jaime; Zerfaoui, Mourad; Rohatgi, Rasika; Boulares, A Hamid; Nichols, Charles D

    2008-11-01

    The G protein-coupled serotonin 5-hydroxytryptamine (5-HT)(2A) receptor is primarily recognized for its role in brain neurotransmission, where it mediates a wide variety of functions, including certain aspects of cognition. However, there is significant expression of this receptor in peripheral tissues, where its importance is largely unknown. We have now discovered that activation of 5-HT(2A) receptors in primary aortic smooth muscle cells provides a previously unknown and extremely potent inhibition of tumor necrosis factor (TNF)-alpha-mediated inflammation. 5-HT(2A) receptor stimulation with the agonist (R)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane [(R)-DOI] rapidly inhibits a variety of TNF-alpha-mediated proinflammatory markers, including intracellular adhesion molecule 1 (ICAM-1), vascular adhesion molecule 1 (VCAM-1), and interleukin (IL)-6 gene expression, nitric-oxide synthase activity, and nuclear translocation of nuclear factor kappaB, with IC(50) values of only 10 to 20 pM. It is significant that proinflammatory markers can also be inhibited by (R)-DOI hours after treatment with TNF-alpha. With the exception of a few natural toxins, no current drugs or small molecule therapeutics demonstrate a comparable potency for any physiological effect. TNF-alpha-mediated inflammatory pathways have been strongly implicated in a number of diseases, including atherosclerosis, rheumatoid arthritis, psoriasis, type II diabetes, depression, schizophrenia, and Alzheimer's disease. Our results indicate that activation of 5-HT(2A) receptors represents a novel, and extraordinarily potent, potential therapeutic avenue for the treatment of disorders involving TNF-alpha-mediated inflammation. Note that because (R)-DOI can significantly inhibit the effects of TNF-alpha many hours after the administration of TNF-alpha, potential therapies could be aimed not only at preventing inflammation but also treating inflammatory injury that has already occurred or is ongoing. PMID

  18. Two types of receptors for 5-hydroxytryptamine on the cholinergic nerves of the guinea-pig myenteric plexus.

    PubMed Central

    Kilbinger, H.; Pfeuffer-Friederich, I.

    1985-01-01

    The effects of 5-hydroxytryptamine (5-HT) on spontaneous and electrically-evoked release of [3H]-acetylcholine (ACh) from guinea-pig myenteric plexus preparations preincubated with [3H]-choline have been investigated in the absence of cholinesterase inhibitors. 5-HT caused a transient increase in spontaneous release and an inhibition of the electrically-evoked release of [3H]-ACh. The 5-HT-induced contractions of the longitudinal muscle were clearly related to the increase in spontaneous release. The inhibitory effect was not due to activation of alpha-adrenoceptors since it was also observed in the presence of tolazoline and on strips from reserpine-pretreated guinea-pigs. After desensitization of the excitatory 5-HT receptors with 5-HT or metoclopramide the effects of 5-HT on spontaneous [3H]-ACh release were largely reduced. A variety of established antagonists at neuronal 5-HT receptors (i.e. metitepine 0.1-1 microM; methysergide 1 microM; ketanserin 0.1-1 microM; MDL 72222 0.1 microM; tropacocaine 1 microM) failed to block the excitation. The inhibition by 5-HT of the electrically evoked [3H]-ACh release was competitively antagonized by metitepine (pA2 7.6) and methysergide (pA2 7.0) but not by ketanserin. Tachyphylaxis to the inhibitory action of 5-HT did not occur. The results suggest that the excitatory 5-HT receptor ('M'-receptor) differs in its pharmacological properties from other neuronal 5-HT receptors. The presynaptically located inhibitory receptor may roughly correspond to the 5-HT1 receptor subtype but probably differs from the 5-HT autoreceptor. PMID:3161573

  19. Changes in 5-hydroxytryptamine and cortisol plasma levels in menopausal women after inhalation of clary sage oil.

    PubMed

    Lee, Kyung-Bok; Cho, Eun; Kang, Young-Sook

    2014-11-01

    The purpose of this study was to examine the antidepressant-like effects of clary sage oil on human beings by comparing the neurotransmitter level change in plasma. The voluntary participants were 22 menopausal women in 50's. Subjects were classified into normal and depression tendency groups using each of Korean version of Beck Depression Inventory-I (KBDI-I), KBDI-II, and Korean version of Self-rating Depression Scale. Then, the changes in neurotransmitter concentrations were compared between two groups. After inhalation of clary sage oil, cortisol levels were significantly decreased while 5-hydroxytryptamine (5-HT) concentration was significantly increased. Thyroid stimulating hormone was also reduced in all groups but not statistically significantly. The different change rate of 5-HT concentration between normal and depression tendency groups was variable according to the depression measurement inventory. When using KBDI-I and KBDI-II, 5-HT increased by 341% and 828% for the normal group and 484% and 257% for the depression tendency group, respectively. The change rate of cortisol was greater in depression tendency groups compared with normal groups, and this difference was statistically significant when using KBDI-II (31% vs. 16% reduction) and Self-rating Depression Scale inventory (36% vs. 8.3% reduction). Among three inventories, only KBDI-II differentiated normal and depression tendency groups with significantly different cortisol level. Finally, clary sage oil has antidepressant-like effect, and KBDI-II inventory may be the most sensitive and valid tool in screening for depression status or severity.

  20. Participation of mast cell 5-hydroxytryptamine in the vasoconstrictor effect of neurotensin in the rat perfused hindquarter.

    PubMed

    Kérouac, R; St-Pierre, S; Rioux, F

    1984-03-01

    Neurotensin (NT) (1 X 10(-8) - 1.5 X 10(-6) g ml-1) caused a transient, dose-dependent increase in perfusion pressure in the rat perfused hindquarter. The vasoconstrictor effect of NT was associated with a short-lived, dose-dependent release of histamine and 5-hydroxytryptamine (5-HT) in the hindquarter effluent. Compound 48/80, a classical mast cell secretagogue, also elicited a vasoconstrictor effect in, and release of histamine from, the rat hindquarter. The vasoconstrictor effect and the release of histamine and 5-HT evoked by NT were much smaller in hindquarters derived from rats pretreated with compound 48/80 for 4 days to cause mast cell depletion than in hindquarters derived from control rats. The mast cell inhibitor cromoglycate (4 mg ml-1) inhibited by about 50% the histamine releasing effect and vasoconstriction produced by the lowest concentrations of NT utilized. The histamine releasing effect of compound 48/80 was more sensitive to blockade by cromoglycate than that of NT. The steroidal antiinflammatory and antiallergic drug dexamethasone did not affect the histamine and 5-HT releasing effect of NT. The vasoconstrictor effects of NT, compound 48/80 and 5-HT were markedly reduced by the 5-HT receptor antagonist methysergide (1 X 10(-7) g ml-1). Histamine (1 X 10(-6) - 10(-4) g ml-1) evoked a decrease in perfusion pressure in hindquarters pre-exposed to noradrenaline. The results suggest the participation of mast cell 5-HT in the vasoconstrictor effect of NT in the rat perfused hindquarter.

  1. Tong Xie Yao Fang relieves irritable bowel syndrome in rats via mechanisms involving regulation of 5-hydroxytryptamine and substance P

    PubMed Central

    Yin, Yue; Zhong, Lei; Wang, Jian-Wei; Zhao, Xue-Ying; Zhao, Wen-Jing; Kuang, Hai-Xue

    2015-01-01

    AIM: To investigate whether the Chinese medicine Tong Xie Yao Fang (TXYF) improves dysfunction in an irritable bowel syndrome (IBS) rat model. METHODS: Thirty baby rats for IBS modeling were separated from mother rats (1 h per day) from days 8 to 21, and the rectum was expanded by angioplasty from days 8 to 12. Ten normal rats were used as normal controls. We examined the effects of TXYF on defection frequency, colonic transit function and smooth muscle contraction, and the expression of 5-hydroxytryptamine (5-HT) and substance P (SP) in colonic and hypothalamus tissues by Western blot and RT-PCT techniques in both normal rats and IBS model rats with characterized visceral hypersensitivity. RESULTS: Defecation frequency was 1.8 ± 1.03 in normal rats and 4.5 ± 1.58 in IBS model rats (P < 0.001). However, the defecation frequency was significantly decreased (3.0 ± 1.25 vs 4.5 ± 1.58, P < 0.05), while the time (in seconds) of colon transit function was significantly increased (256.88 ± 20.32 vs 93.36 ± 17.28, P < 0.001) in IBS + TXYF group rats than in IBS group rats. Increased colonic smooth muscle tension and contract frequency in IBS model rats were significantly decreased by administration of TXYF. Exogenous agonist stimulants increased spontaneous activity and elicited contractions of colon smooth muscle in IBS model rats, and all of these actions were significantly reduced by TXYF involving 5-HT and SP down-regulation. CONCLUSION: TXYF can modulate the activity of the enteric nervous system and alter 5-HT and SP activities, which may contribute to the symptoms of IBS. PMID:25914462

  2. Transcriptome fingerprints distinguish hallucinogenic and nonhallucinogenic 5-hydroxytryptamine 2A receptor agonist effects in mouse somatosensory cortex.

    PubMed

    González-Maeso, Javier; Yuen, Tony; Ebersole, Barbara J; Wurmbach, Elisa; Lira, Alena; Zhou, Mingming; Weisstaub, Noelia; Hen, Rene; Gingrich, Jay A; Sealfon, Stuart C

    2003-10-01

    Most neuropharmacological agents and many drugs of abuse modulate the activity of heptahelical G-protein-coupled receptors. Although the effects of these ligands result from changes in cellular signaling, their neurobehavioral activity may not correlate with results of in vitro signal transduction assays. 5-Hydroxytryptamine 2A receptor (5-HT2AR) partial agonists that have similar pharmacological profiles differ in the behavioral responses they elicit. In vitro studies suggest that different agonists acting at the same receptor may establish distinct patterns of signal transduction. Testing this hypothesis in the brain requires a global signal transduction assay that is applicable in vivo. To distinguish the cellular effects of the different 5-HT2AR agonists, we developed an assay for global signal transduction on the basis of high throughput quantification of rapidly modulated transcripts. Study of the responses to agonists in human embryonic kidney 293 cells stably expressing 5-HT2ARs demonstrated that each agonist elicits a distinct transcriptome fingerprint. We therefore studied behavioral and cortical signal transduction responses in wild-type and 5-HT2AR null-mutant mice. The hallucinogenic chemicals (+/-)-2,5-dimethoxy-4-iodoamphetamine (DOI) and lysergic acid diethylamide (LSD) stimulated a head-twitch behavioral response that was not observed with the nonhallucinogenic lisuride hydrogen maleate (LHM) and was absent in receptor null-mutant mice. We also found that DOI, LSD, and LHM each induced distinct transcriptome fingerprints in somatosensory cortex that were absent in 5-HT2AR null-mutants. Moreover, DOI and LSD showed similarities in the transcriptome fingerprints obtained that were not observed with the behaviorally inactive drug LHM. Our results demonstrate that chemicals acting at the 5-HT2AR induce specific cellular response patterns in vivo that are reflected in unique changes in the somatosensory cortex transcriptome.

  3. Chronic oral nicotine administration affects the circadian rhythm of dopamine and 5-hydroxytryptamine metabolism in the striata of mice.

    PubMed

    Pietila, K; Laakso, I; Ahtee, L

    1995-12-01

    The effect of chronic oral administration of nicotine on the circadian rhythm of striatal dopamine (DA) and 5-hydroxytryptamine (5-HT) was studied in mice. Mice receiving nicotine in their drinking water and control mice drinking tap water were killed at 05:00, 11:00, 15:00 or 21:00 hours on the 50th day of chronic administration. The plasma concentrations of nicotine and cotinine, as well the striatal concentrations of DA, 5-HT and their metabolites 3,4 dihydroxyphenylacetic acid (DOPAC), 3-methoxytyramine (3-MT), homovanilic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) were estimated. The largest plasma concentrations of nicotine and cotinine were found at 05:00, when they were more than double the concentrations found at the other times studied. This indicates that the mice, typically for nocturnal animals, consumed most of their daily drinking water at night. In the control mice, the striatal DA and 3-MT concentrations showed circadian variation and were lowest at 11:00. The 5-HIAA concentrations also varied, being highest at 11:00. In the nicotine-treated mice the circadian variations in striatal monoamines were altered and more pronounced than in the controls. The concentrations of DA, DOPAC, HVA and 5-HIAA were highest at 11:00 and that of 5-HT at 21:00. The striatal DA, DOPAC, HVA and 5-HIAA concentrations in the nicotine-treated mice were significantly higher at 11:00 and the 5-HT concentrations at 21:00 than in the control mice, and, in contrast to the control mice, in the mice treated with chronic nicotine no circadian rhythm was observed in the 3-MT. No elevation of striatal DA metabolites occurred in the nicotine-treated mice compared with the controls when the plasma nicotine concentration was at its peak at 05:00. This finding suggests development of tolerance to the nicotine-induced changes in striatal DA metabolism. Further, our findings suggest that the chronic administration of nicotine in the drinking water of mice alters the circadian

  4. Vasodilator and vasoconstrictor responses induced by 5-hydroxytryptamine in the in situ blood autoperfused hindquarters of the anaesthetized rat.

    PubMed

    Calama, E; Fernández, M M; Morán, A; Martín, M L; San Román, L

    2002-08-01

    In the present study we attempted to characterise the responses and receptors involved in the effects of 5-hydroxytryptamine (5-HT, serotonin) in in situ autoperfused rat hindquarters. Intra-arterial administration of the lowest doses of 5-HT used (0.12-12.5 ng/kg) induced vasodilator responses, whereas the highest doses (25-1000 ng/kg) produced vasoconstriction. The vasodilator effect was inhibited by methiothepin (a non-specific 5-HT(1,2,5,6,7) receptor antagonist) and by a 5-HT(1D/1B) receptor antagonist, i.e., 3-[4-(4-chlorophenyl)piperazin-1-yl]-1,1-diphenyl-2-propanolol (BRL 15572), but not by ritanserin (a selective 5-HT(2) receptor antagonist), 5-methyl-1-(3-pyridylcarbamoyl)-1,2,3,5-tetrahydropyrrolo[2,3-f] indole (SB 206553, a selective 5-HT(2B/2C) receptor antagonist) or mesulergine (a non-specific serotonergic antagonist that shows affinity to the 5-HT(7) receptor). This vasodilator effect was mimicked by administration of a selective 5-HT(1) receptor agonist - 5-carboxamidotryptamine (5-CT) - and by 2-[5-[3-(4-methylsulphonylamino)benzyl-1,2,4-1 H-indol-3-yl]ethanamine (L-694,247, a selective 5-HT(1D/1B) receptor agonist). Methiothepin, but not mesulergine, inhibited 5-CT-induced vasodilatation and the selective 5-HT(1D/1B) receptor antagonist (BRL 15572) inhibited the vasodilator action induced by L-694,247. The vasoconstrictor effect of 5-HT was significantly decreased by methiothepin, ritanserin and SB 206553, and was mimicked by alpha-methyl-5-HT (a selective 5-HT(2) receptor agonist) but not by administration of BW 723C86, a selective 5HT(2B) receptor agonist. Ritanserin, SB 206553 and spiperone (a non-specific 5-HT(1/2A) receptor antagonist) inhibited the alpha-methyl-5HT-induced vasoconstriction.Our data suggest that the vasodilator response induced by 5-HT in autoperfused rat hindquarters is mainly mediated by 5-HT(1D/1B) receptors, whereas the vasoconstrictor effect is mainly due to the activation of 5-HT(2A) receptors.

  5. Pharmacological activity of (-)-discretamine, a novel vascular alpha-adrenoceptor and 5-hydroxytryptamine receptor antagonist, isolated from Fissistigma glaucescens.

    PubMed

    Ko, F N; Yu, S M; Su, M J; Wu, Y C; Teng, C M

    1993-10-01

    1. The pharmacological activity of (-)-discretamine, isolated from Fissistigma glaucescens, was determined in rat isolated thoracic aorta, cardiac tissues and ventricular myocytes and guinea-pig isolated trachea. 2. (-)-Discretamine was found to be an alpha 1-adrenoceptor blocking agent in rat thoracic aorta as revealed by its competitive antagonism of noradrenaline (pA2 = 7.20 +/- 0.10)- or phenylephrine (pA2 = 7.60 +/- 0.09)-induced vasoconstriction. It was as potent as phentolamine (pA2 = 7.51 +/- 0.10), but was more potent than yohimbine (pA2 = 6.18 +/- 0.06). Removal of endothelium significantly increased the antagonistic potency of (-)-discretamine on noradrenaline (pA2 = 7.52 +/- 0.09)- or phenylephrine (pA2 = 7.90 +/- 0.09)-induced vasoconstriction. 3. (-)-Discretamine was also an alpha 2-adrenoceptor blocking agent (pA2 = 6.30 +/- 0.15) and a 5-hydroxytryptamine antagonist (pA2 = 6.87 +/- 0.06), both in rat aorta denuded of endothelium. 4. (-)-Discretamine protected alpha-adrenoceptors from alkylation by the irreversible blocking agent, phenoxybenzamine. 5. [3H]-inositol monophosphate formation caused by noradrenaline (3 microM) in rat thoracic aorta was suppressed by (-)-discretamine (10 and 30 microM) and prazosin (3 microM). 6. A high concentration of (-)-discretamine (30 microM) did not affect the contraction induced by the thromboxane receptor agonist U-46619, prostaglandin F2 alpha (PGF2 alpha), angiotensin II, high K+ or endothelin in rat aorta denuded of endothelium. Neither cyclic AMP nor cyclic GMP content of rat thoracic aorta was changed by (-)-discretamine. 7. Contraction of guinea-pig trachea caused by histamine, leukotriene C4 or carbachol was not affected by (-)-discretamine (30 microM). (-)-Discretamine also did not block beta l- or beta2-adrenoceptor-mediated responses induced by isoprenaline in rat right atria and guinea-pig trachea.8. A voltage clamp study in rat ventricular single myocytes revealed that sodium inward current, slow

  6. A Sex-Specific MicroRNA-96/5-Hydroxytryptamine 1B Axis Influences Development of Pulmonary Hypertension

    PubMed Central

    Wallace, Emma; Morrell, Nicholas W.; Yang, Xudong D.; Long, Lu; Stevens, Hannah; Nilsen, Margaret; Loughlin, Lynn; Mair, Kirsty M.; Baker, Andrew H.

    2015-01-01

    Rationale: Females are predisposed to pulmonary arterial hypertension (PAH); evidence suggests that serotonin, mutations in the bone morphogenetic protein receptor (BMPR) II gene, and estrogens influence development of PAH. The 5-hydroxytryptamine 1B receptor (5-HT1BR) mediates human pulmonary artery smooth muscle cell (hPASMC) proliferation. Objectives: We aimed to determine whether selected microRNAs (miRNAs) expressed in PASMCs are influenced by sex, BMPR-II mutations, and estrogens, and contribute to PASMC proliferation in PAH. Methods: Expression levels of miRNAs targeting genes related to PAH, estrogen, and serotonin were determined by quantitative RT-PCR in hPASMCs and mouse PASMCs harboring a heterozygous mutation in BMPR-II (BMPR-IIR899X+/− PASMCs). miRNA-96 targets 5-HT1BR and was selected for further investigation. miRNA target validation was confirmed by luciferase reporter assay. Precursor miRNA-96 was transfected into hPASMCs to examine effects on proliferation and 5-HT1BR expression. The effect of a miRNA-96 mimic on the development of hypoxic pulmonary hypertension in mice was also assessed. Measurements and Main Results: miRNA-96 expression was reduced in BMPR-IIR899X+/− PASMCs from female mice and hPASMCs from female patients with PAH; this was associated with increased 5-HT1BR expression and serotonin-mediated proliferation. 5-HT1BR was validated as a target for miRNA-96. Transfection of precursor miRNA-96 into hPASMCs reduced 5-HT1BR expression and inhibited serotonin-induced proliferation. Restoration of miRNA-96 expression in pulmonary arteries in vivo via administration of an miRNA-96 mimic reduced the development of hypoxia-induced pulmonary hypertension in the mouse. Conclusions: Increased 5-HT1BR expression may be a consequence of decreased miRNA-96 expression in female patient PASMCs, and this may contribute to the development of PAH. PMID:25871906

  7. Does pharmacogenomics account for variability in control of acute chemotherapy-induced nausea and vomiting with 5-hydroxytryptamine type 3 receptor antagonists?

    PubMed

    Trammel, Morgan; Roederer, Mary; Patel, Jai; McLeod, Howard

    2013-06-01

    Chemotherapy-induced nausea and vomiting is one of the most concerning adverse drug effects from cytotoxic chemotherapy. Despite appropriate use of antiemetic guidelines, 20-30 % of patients experience breakthrough nausea and vomiting secondary to chemotherapy. To assess the variability of 5-hydroxytryptamine type 3 receptor antagonist efficacy caused by genetic variation, a review of the available literature was conducted. From the literature, three sources of pharmacogenomic variability were identified: polymorphisms associated with 5-hydroxytryptamine type 3 receptor subunits, drug metabolism via cytochromes P450, and drug transport in the body. Testing for receptor subunit polymorphisms is not applicable to a clinical setting at this time; however, cytochrome P450 2D6 testing is FDA-approved and widely accessible. Cytochrome P450 2D6 ultrarapid metabolizers and poor metabolizers displayed altered antiemetic efficacy when compared with intermediate metabolizers and extensive metabolizers. We postulate that testing for cytochrome P450 2D6 phenotypes may be the most accessible way to provide individualized antiemetic therapy in the future.

  8. Blockade of 5-hydroxytryptamine3 receptors prevents cisplatin-induced but not motion- or xylazine-induced emesis in the cat

    NASA Technical Reports Server (NTRS)

    Lucot, J. B.

    1989-01-01

    5-Hydroxytryptamine3 antagonists have been reported to prevent emesis elicited by cisplatin and radiation. This study investigated the possibility that drugs with this mechanism of action may be useful in preventing emesis elicited by other stimuli. The drugs ICS 205-930 (0.1 and 1.0 mg/kg) and MDL 72222 (0.1 and 1.0 mg/kg) were administered SC to cats before challenging them with either provocative motion or an emetic dose of xylazine. In no instance was a significant reduction in emesis evident. Zacopride was also administered before motion testing (0.01 to 10.0 mg/kg) and found to not have efficacy. To test the possibility that species or route of administration were factors in the negative results, 1.0 mg/kg of ICS 205-930 was administered SC before IV infusion of 7.5 mg/kg of cisplatin. There was a total suppression of emesis for the duration of the six-hour observation periods. This result verifies other work which found 5-hydroxytryptamine3 antagonists to be effective in preventing emesis elicited by cancer chemotherapeutic treatments. However, there is no evidence that they are effective in other syndromes, such as motion sickness and xylazine-induced emesis.

  9. Prophylaxis of Radiation-Induced Nausea and Vomiting Using 5-Hydroxytryptamine-3 Serotonin Receptor Antagonists: A Systematic Review of Randomized Trials

    SciTech Connect

    Salvo, Nadia; Doble, Brett; Khan, Luluel; Amirthevasar, Gayathri; Dennis, Kristopher; Pasetka, Mark; DeAngelis, Carlo; Tsao, May; Chow, Edward

    2012-01-01

    Purpose: To systematically review the effectiveness and safety of 5-hydroxytryptamine-3 receptor antagonists (5-HT3 RAs) compared with other antiemetic medication or placebo for prophylaxis of radiation-induced nausea and vomiting. Methods and Materials: We searched the following electronic databases: MEDLINE, Embase, the Cochrane Central Register of Controlled Clinical Trials, and Web of Science. We also hand-searched reference lists of included studies. Randomized, controlled trials that compared a 5-HT3 RA with another antiemetic medication or placebo for preventing radiation-induced nausea and vomiting were included. We excluded studies recruiting patients receiving concomitant chemotherapy. When appropriate, meta-analysis was conducted using Review Manager (v5) software. Relative risks were calculated using inverse variance as the statistical method under a random-effects model. We assessed the quality of evidence by outcome using the Grading of Recommendations Assessment, Development, and Evaluation approach. Results: Eligibility screening of 47 articles resulted in 9 included in the review. The overall methodologic quality was moderate. Meta-analysis of 5-HT3 RAs vs. placebo showed significant benefit for 5-HT3 RAs (relative risk [RR] 0.70; 95% confidence interval [CI] 0.57-0.86 for emesis; RR 0.84, 95% CI 0.73-0.96 for nausea). Meta-analysis comparing 5-HT3 RAs vs. metoclopramide showed a significant benefit of the 5-HT3 RAs for emetic control (RR 0.27, 95% CI 0.15-0.47). Conclusion: 5-Hydroxytryptamine-3 RAs are superior to placebo and other antiemetics for prevention of emesis, but little benefit was identified for nausea prevention. 5-Hydroxytryptamine-3 RAs are suggested for prevention of emesis. Limited evidence was found regarding delayed emesis, adverse events, quality of life, or need for rescue medication. Future randomized, controlled trials should evaluate different 5-HT3 antiemetics and new agents with novel mechanisms of action such at the NK

  10. Comparison of the performance of different DFT methods in the calculations of the molecular structure and vibration spectra of serotonin (5-hydroxytryptamine, 5-HT)

    NASA Astrophysics Data System (ADS)

    Yang, Yue; Gao, Hongwei

    2012-04-01

    Serotonin (5-hydroxytryptamine, 5-HT) is a monoamine neurotransmitter which plays an important role in treating acute or clinical stress. The comparative performance of different density functional theory (DFT) methods at various basis sets in predicting the molecular structure and vibration spectra of serotonin was reported. The calculation results of different methods including mPW1PW91, HCTH, SVWN, PBEPBE, B3PW91 and B3LYP with various basis sets including LANL2DZ, SDD, LANL2MB, 6-31G, 6-311++G and 6-311+G* were compared with the experimental data. It is remarkable that the SVWN/6-311++G and SVWN/6-311+G* levels afford the best quality to predict the structure of serotonin. The results also indicate that PBEPBE/LANL2DZ level show better performance in the vibration spectra prediction of serotonin than other DFT methods.

  11. Blockade of 5-hydroxytryptamine(3) receptors prevents cisplatin-induced but not motion- or xylazine-induced emesis in the cat

    NASA Technical Reports Server (NTRS)

    Lucot, James B.

    1989-01-01

    The effects of the 5-hydroxytryptamine(3) (5-HT-3) antagonists ICS 205-930 and MDL 72222 on the emesis induced by motion or by emetic doses of xylazine (0.66 mg/kg administered SC) or cisplatin (7.5 mg/kg infused over a period of 4-5 min) were investigated in cats. It was found that neither the low (0.1 mg/kg) or the high (1.0 mg.kg) doses of ICS 205-930 or MDL 72222 prevented emesis elicited by screening motion challenges or xylazine. On the other hand, treatment cats by 1.0 mg/kg of ICS 205-930 was effective against cisplatin-induced motion sickness, in agreement with earlier results obtained on other mammals.

  12. Protein kinase C modulates the release of [3H]5-hydroxytryptamine in the spinal cord of the rat: the role of L-type voltage-dependent calcium channels.

    PubMed

    Gandhi, V C; Jones, D J

    1992-11-01

    The present studies examined the relationship between protein kinase C (PKC) and L-type voltage-dependent calcium channels in modulating the release of neurotransmitter from K(+)-depolarized rat spinal cord synaptosomes. Activators of PKC, such as phorbol 12-myristate 13-acetate (PMA), mezerein and oleoyl acetylglycerol produced a concentration-dependent potentiation of K(+)-induced release of [3H]5-hydroxytryptamine ([3H]5-HT). Enhanced release was dependent on the concentration of both Ca2+ and K+ in the superfusion medium. Calcium-independent release of [3H]5-HT or release induced by the Ca2+ ionophore were unaffected by PKC activators. Calcium-dependent release of [3H]5-HT, evoked by K+, was enhanced under similar conditions by the L-type Ca2+ channel agonists Bay K 8644 and (+)-SDZ 202-791. Nimodipine, an L-type Ca2+ channel antagonist, while having no independent effect on K(+)-induced release of [3H]5-HT, abolished the potentiative effects of Bay K 8644 and PMA. Similarly, the PKC inhibitors, polymyxin B and staurosporine, blocked effects of both PMA and Bay K 8644 on K(+)-stimulated release of [3H]5-HT. Neither PMA nor Bay K 8644 altered the uptake of [3H]5-HT. These results suggest that PKC-dependent mechanisms utilize calcium influx, via the L-type calcium channel, to modulate release of neurotransmitter and indicate a possible functional link between PKC and L-type voltage-dependent calcium channels in the spinal cord.

  13. Reduced number of caudate nucleus dopamine uptake sites in vascular dementia.

    PubMed

    Allard, P; Englund, E; Marcusson, J

    1999-01-01

    The dopamine (DA) uptake sites in the caudate nucleus were studied in patients with vascular dementia (VAD) and in a control group using the presynaptic DA uptake site marker [3H][2beta-carbomethoxy-3beta-(4-fluorophenyl) tropane] as radioligand. There was a significant decrease in the number of DA uptake sites in the VAD group, while the binding affinity was unchanged. The present results indicate that in the patients investigated, the cerebrovascular disease process involves dopaminergic neuron terminals in the caudate nucleus. Our findings are discussed in relation to the reductions in number of DA uptake sites that have previously been revealed in Alzheimer's and Parkinson's diseases.

  14. Effect of prolonged 5-hydroxytryptamine uptake inhibition by paroxetine on cortical. beta. sub 1 and. beta. sub 2 -adrenoceptors in rat brain

    SciTech Connect

    Nelson, D.R.; Palmer, K.J.; Johnson, A.M. )

    1990-01-01

    The effects of prolonged oral administration of the antidepressants paroxetine and amitriptyline on rat brain cortical {beta}{sub 1}- and {beta}{sub 2}-adrenoceptor numbers and affinities were investigated using ({sup 3}H)-CGP 12177. Although amitriptyline, 27 mg/kg, caused a significant 20% reduction in the number of {beta}{sub 1}-adrenoceptors, paroxetine, at does up to 8.9 mg/kg p.o., did not influence binding of ({sup 3}H)-CGP 12177 to cortical {beta}{sub 1}- or {beta}{sub 2}-adrenoceptors. This study with paroxetine provides further evidence that the down-regulation of central {beta}{sub 1}-adrenoceptors in rat brain after repeated administration is not a property of all antidepressant drugs.

  15. A phase 1 randomized study evaluating the effect of omeprazole on the pharmacokinetics of a novel 5-hydroxytryptamine receptor 4 agonist, revexepride (SSP-002358), in healthy adults

    PubMed Central

    Pierce, David; Corcoran, Mary; Velinova, Maria; Hossack, Stuart; Hoppenbrouwers, Mieke; Martin, Patrick

    2015-01-01

    Background About 30% of patients with gastroesophageal reflux disease continue to experience symptoms despite treatment with proton pump inhibitors. The 5-hydroxytryptamine 4 receptor agonist revexepride (SSP-002358) is a novel prokinetic that stimulates gastrointestinal motility, which has been suggested as a continued cause of symptoms in these patients. The aim of this study was to assess whether revexepride pharmacokinetics were affected by co-administration of omeprazole, in preparation for a proof-of-concept evaluation of revexepride added to proton pump inhibitor treatment. Methods In this phase 1, open-label, randomized, two-period crossover study, healthy adults aged 18–55 years were given a single dose of revexepride 1 mg or revexepride 1 mg + omeprazole 40 mg. Pharmacokinetic parameters were assessed for up to 48 hours after administration of the investigational product. Adverse events, clinical chemistry and hematology parameters, electrocardiograms, and vital signs were monitored. Results In total, 42 participants were enrolled and 40 completed the study. The median age was 24 years (18–54 years), 55% were women and 93% were white. The pharmacokinetic parameters of revexepride were similar without or with omeprazole co-administration. The mean area under the plasma concentration–time curve from time 0 to infinity (AUC0–∞) was 23.3 ng · h/mL (standard deviation [SD]: 6.33 ng · h/mL) versus 24.6 ng · h/mL (SD: 6.31 ng · h/mL), and maximum plasma concentrations (Cmax) were 3.89 ng/mL (SD: 1.30 ng/mL) and 4.12 ng/mL (SD: 1.29 ng/mL) in participants without and with omeprazole, respectively. For AUC0–∞ and Cmax, the 90% confidence intervals for the ratios of geometric least-squares means (with:without omeprazole) were fully contained within the pre-defined equivalence limits of 0.80–1.25. Mean apparent terminal phase half-life was 9.95 hours (SD: 2.06 hours) without omeprazole, and 11.0 hours (SD: 3.25 hours) with omeprazole. Conclusion

  16. Lack of systematic effects of the 5-hydroxytryptamine 3 receptor antagonist ICS 205-930 on gastric emptying and antral motor activity in patients with primary anorexia nervosa.

    PubMed Central

    Stacher, G; Bergmann, H; Granser-Vacariu, G V; Wiesnagrotzki, S; Wenzelabatzi, T A; Gaupmann, G; Kugi, A; Steinringer, H; Schneider, C; Höbart, J

    1991-01-01

    1. The 5-hydroxytryptamine 3 receptor antagonist, ICS 205-930, has been reported to have potent effects on gastric smooth muscle and to enhance gastric emptying in animals, but findings in man have been inconsistent. 2. This study investigated the effects of ICS 205-930 on gastric emptying of an isotopically labelled semisolid 1168 kJ meal and on antral contractility in patients with primary anorexia nervosa, a condition frequently associated with impaired gastric motor function. 3. Thirteen female patients (age 18-39 years, median 22 years; percentage of ideal body weight 52-90%, median 66%) participated each in two studies, in which 0.15-0.18 mg kg-1 ICS 205-930 or placebo were infused i.v. in crossover, double-blind fashion. Gastric emptying and antral contractility were recorded scintigraphically for 50 min. 4. ICS 205-930 did not affect gastric emptying: the mean percentage of meal remaining in the stomach after 50 min (69.6% +/- 3.2 s.e. mean) was nearly identical to that after placebo (70.7 +/- 3.3%). 5. Amplitude, frequency and propagation velocity of antral contractions differed only little after ICS 205-930 and placebo, respectively. 6. The results show that ICS 205-930 has no effect on the impaired gastric motor activity in primary anorexia nervosa and thus provide further evidence that the compound does not have prominent prokinetic effects in man. PMID:1768560

  17. Sensitive determination of norepinephrine, epinephrine, dopamine and 5-hydroxytryptamine by coupling HPLC with [Ag(HIO6 )2 ](5-) -luminol chemiluminescence detection.

    PubMed

    Wu, Dong; Xie, He; Lu, Haifeng; Li, Wei; Zhang, Qunlin

    2016-09-01

    Based on the enhancing effects of norepinephrine (NE), epinephrine (EP), dopamine (DA) and 5-hydroxytryptamine (5-HT) on the chemiluminescence (CL) reaction between [Ag(HIO6 )2 ](5-) and luminol in alkaline solution, a high-performance liquid chromatography (HPLC) method with CL detection was explored for the sensitive determination of monoamine neurotransmitters for the first time. The UV-visible absorption spectra were recorded to study the enhancement mechanism of monoamine neurotransmitters on the CL of [Ag(HIO6 )2 ](5-) and luminol reaction. The HPLC separation of NE, EP, DA and 5-HT was achieved with isocratic elution using a mixture of aqueous 0.2% phosphoric acid and methanol (5:95, v/v) within 11.0 min. Under the optimized conditions, the detection limits of NE, EP, DA, and 5-HT were 4.8, 0.9, 1.9 and 2.3 ng/mL, respectively, corresponding to 17.6-96.0 pg for 20 μL sample injection. The recoveries of monoamine neurotransmitters in rat brain were >95.6% with the precisions expressed by RSD <5.0%. The validated HPLC-CL method was successfully applied for the quantification of NE, EP, DA and 5-HT in rat brain. This method has promising potential for some biological and clinical investigations focusing on the levels of monoamine neurotransmitters. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26876580

  18. Detection of 5-hydroxytryptamine (5-HT) in vitro using a hippocampal neuronal network-based biosensor with extracellular potential analysis of neurons.

    PubMed

    Hu, Liang; Wang, Qin; Qin, Zhen; Su, Kaiqi; Huang, Liquan; Hu, Ning; Wang, Ping

    2015-04-15

    5-hydroxytryptamine (5-HT) is an important neurotransmitter in regulating emotions and related behaviors in mammals. To detect and monitor the 5-HT, effective and convenient methods are demanded in investigation of neuronal network. In this study, hippocampal neuronal networks (HNNs) endogenously expressing 5-HT receptors were employed as sensing elements to build an in vitro neuronal network-based biosensor. The electrophysiological characteristics were analyzed in both neuron and network levels. The firing rates and amplitudes were derived from signal to determine the biosensor response characteristics. The experimental results demonstrate a dose-dependent inhibitory effect of 5-HT on hippocampal neuron activities, indicating the effectiveness of this hybrid biosensor in detecting 5-HT with a response range from 0.01μmol/L to 10μmol/L. In addition, the cross-correlation analysis of HNNs activities suggests 5-HT could weaken HNN connectivity reversibly, providing more specificity of this biosensor in detecting 5-HT. Moreover, 5-HT induced spatiotemporal firing pattern alterations could be monitored in neuron and network levels simultaneously by this hybrid biosensor in a convenient and direct way. With those merits, this neuronal network-based biosensor will be promising to be a valuable and utility platform for the study of neurotransmitter in vitro.

  19. Depressive behavior and alterations in receptors for dopamine and 5-hydroxytryptamine in the brain of the senescence accelerated mouse (SAM)-P10.

    PubMed

    Onodera, T; Watanabe, R; Tha, K K; Hayashi, Y; Murayama, T; Okuma, Y; Ono, C; Oketani, Y; Hosokawa, M; Nomura, Y

    2000-08-01

    The senescence accelerated mouse (SAM) is known as a murine model of aging. SAM consists of senescence accelerated-prone mouse (SAMP) and senescence accelerated-resistant mouse (SAMR). Previous studies reported that SAMP10 exhibits age-related learning impairments and behavioral depression in a tail suspension test after 7 months. We investigated the changes in emotional behavior in a forced swimming test and in receptors for dopamine and 5-hydroxytryptamine (5-HT) in SAMP10. SAMP10 at 8 months showed an increase of immobility in the test compared with SAMR1. Treatment with desipramine (25 mg/kg, i.p., 3 days) in SAMP10 caused a decrease in immobility. In the cortex from SAMP10, [3H]quinpirole binding to D2/D3 dopamine receptors increased significantly compared with control SAMR1. In the hippocampus from SAMP10, [3H]8-hydroxy DPAT binding to 5-HT1A receptor increased. In midbrains from SAMP10, bindings of [3H]quinpirole and [3H]8-hydroxy DPAT increased. [3H]SCH23390 binding to D1/D5 receptors and [3H]ketanserin binding to 5-HT2 receptor in brain regions examined in SAMP10 were similar to those in SAMR1. The present findings represent the first neurochemical evidence of an increase of D2/D3 and 5-HT1A receptors in SAMP10. SAMP10 may be a useful model of aging associated depressive behavior. PMID:11001177

  20. Interaction between the effects of 5-hydroxytryptamine and adrenaline on the growth of platelet thrombi in the coronary artery of the anaesthetized dog.

    PubMed Central

    McAuliffe, S. J.; Snow, H. M.; Cox, B.; Smith, C. C.; Noble, M. I.

    1993-01-01

    1. The interaction between adrenaline and 5-hydroxytryptamine (5-HT) has been quantitated on the rate of thrombus formation, in the stenosed coronary artery with damaged endothelium of the anaesthetized dog. 2. Changes in the plasma concentration of adrenaline were produced by varying the rate of an intravenous infusion of adrenaline and in the effects of 5-HT, by intravenous injections of the selective 5-HT2 receptor antagonist, ICI 170809. 3. Increases in the plasma concentration of adrenaline, which did not cause significant changes in blood pressure and heart rate, increased the rate of thrombus formation. 4. Antagonism of the 5-HT2 receptor by ICI 170809, in the absence of an infusion of adrenaline, abolished thrombus formation (mean ED50 0.41 microgram kg-1, i.v.). 5. The effects of adrenaline were non-competitively antagonized by ICI 170809; maximum effects were obtained in the dose-range 50-200 micrograms kg-1, i.v., when the mean dose-ratio increase in adrenaline required to restore equivalent rates of thrombus formation was 39 fold. 6. These results are consistent with a synergism between adrenaline and 5-HT and emphasize the importance of both on thrombus formation. PMID:8358542

  1. Anxiolytic-like profile of mirtazapine in rat conditioned fear stress model: Functional significance of 5-hydroxytryptamine 1A receptor and alpha1-adrenergic receptor.

    PubMed

    Kakui, Nobukazu; Yokoyama, Fumikazu; Yamauchi, Miki; Kitamura, Koichi; Imanishi, Taiichiro; Inoue, Takeshi; Koyama, Tsukasa

    2009-05-01

    Mirtazapine is an antidepressant with a unique mechanism of action and has been categorized as a Noradrenergic and Specific Serotonergic Antidepressant (NaSSA). Although numerous clinical trials suggested the usefulness of mirtazapine for not only major depressive disorders but also a variety of anxiety disorders, efficacy studies in animal anxiety models have been rarely reported. The present study investigated a potential anxiolytic-like profile of mirtazapine in rat conditioned fear stress model. A 5-hydroxytryptamine (5-HT) 1A receptor partial agonist, buspirone (1-5 mg/kg) exhibited a significant reduction in freezing time, and its maximal effect was reversed by a selective 5-HT(1A) antagonist, WAY-100635 (1 mg/kg). Mirtazapine (1-10 mg/kg) also reduced the freezing time in a dose-related fashion, a substantial proportion (approx. 50%) of which was likewise antagonized by WAY-100635 (1 mg/kg). Mianserin (1-30 mg/kg), a structural analogue for mirtazapine, was ineffective. Furthermore, co-administration of alpha1 adrenoceptor antagonist, prazosin (0.03 mg/kg) completely reversed mirtazapine (10 mg/kg)-induced reduction of freezing time. These findings represent the first demonstration that the anxiolytic-like action of mirtazapine involves activation of 5-HT(1A) receptor and alpha1 adrenoceptor to different extents, and are compatible with one aspect of mirtazapine's pharmacological profile as NaSSA. PMID:19167420

  2. The mechanism of body temperature changes induced by intraventricular injections of adrenaline, noradrenaline and 5-hydroxytryptamine in the ox (Bos taurus).

    PubMed

    Findlay, J D; Robertshaw, D

    1967-04-01

    1. Adrenaline, noradrenaline and 5-hydroxytryptamine (5-HT) were injected into the lateral ventricle of the ox. The effect of these drugs was measured on the respiratory rate, tidal volume, heat production, skin temperature of the ear, evaporative loss from the skin and the rectal temperature at 20 and 10 degrees C ambient temperature.2. Neither adrenaline (3 mg) nor noradrenaline (3 mg) had any effect on the temperature regulating mechanisms of the ox, except to produce vasoconstriction if vasodilatation was already present due to high ambient temperature or previous injection of 5-HT.3. Injection of 5-HT (5 mg) caused a rise in respiratory rate, a fall in tidal volume and heat production, elevation of ear skin temperature and skin evaporative loss and a decrease in rectal temperature. Sedation of the animals occurred.4. In its reaction to these monoamines the ox is similar to the goat, sheep and rabbit, but is unlike the cat and dog.5. It was concluded that neither adrenaline nor noradrenaline has a role in the central control of temperature regulation in the ox, but that 5-HT may be involved in the control of heat dissipation mechanisms.

  3. Postnatal Treadmill Exercise Alleviates Prenatal Stress-Induced Anxiety in Offspring Rats by Enhancing Cell Proliferation Through 5-Hydroxytryptamine 1A Receptor Activation

    PubMed Central

    2016-01-01

    Purpose: Stress during pregnancy is a risk factor for the development of anxiety-related disorders in offspring later in life. The effects of treadmill exercise on anxiety-like behaviors and hippocampal cell proliferation were investigated using rats exposed to prenatal stress. Methods: Exposure of pregnant rats to a hunting dog in an enclosed room was used to induce stress. Anxiety-like behaviors of offspring were evaluated using the elevated plus maze test. Immunohistochemistry for the detection of 5-bromo-2ʹ- deoxyuridine and doublecortin (DCX) in the hippocampal dentate gyrus and 5-hydroxytryptamine 1A receptors (5-HT1A) in the dorsal raphe was conducted. Brain-derived neurotrophic factor (BDNF) and tyrosine kinase B (TrkB) levels in the hippocampus were evaluated by western blot analysis. Results: Offspring of maternal rats exposed to stress during pregnancy showed anxiety-like behaviors. Offspring also showed reduced expression of BDNF, TrkB, and DCX in the dentate gyrus, decreased cell proliferation in the hippocampus, and reduced 5-HT1A expression in the dorsal raphe. Postnatal treadmill exercise by offspring, but not maternal exercise during pregnancy, enhanced cell proliferation and expression of these proteins. Conclusions: Postnatal treadmill exercise ameliorated anxiety-like behaviors in offspring of stressed pregnant rats, and the alleviating effect of exercise on these behaviors is hypothesized to result from enhancement of cell proliferation through 5-HT1A activation in offspring rats. PMID:27230461

  4. The action of SDZ 205,557 at 5-hydroxytryptamine (5-HT3 and 5-HT4) receptors.

    PubMed Central

    Eglen, R. M.; Alvarez, R.; Johnson, L. G.; Leung, E.; Wong, E. H.

    1993-01-01

    1. The interaction of the novel antagonist, SDZ 205,557 (2-methoxy-4-amino-5-chloro benzoic acid 2-(diethylamino) ethyl ester), at 5-HT3 and 5-HT4 receptors has been assessed in vitro and in vivo. 2. In guinea-pig hippocampus and in the presence of 0.4 microM 5-carboxamidotryptamine, 5-HT4-mediated stimulation of adenylyl cyclase was competitively antagonized by SDZ 205,557, with a pA2 value of 7.5, and a Schild slope of 0.81. In rat carbachol-contracted oesophagus, 5-HT4-receptor mediated relaxations were surmountably antagonized by SDZ 205,557 with a similar pA2 value (7.3). This value was agonist-independent with the exception of (R)-zacopride, against which a significantly lower value (6.4) was observed. 3. In functional studies of 5-HT3 receptors, SDZ 205,557 exhibited an affinity of 6.2 in guinea-pig ileum compared with 6.9 at binding sites labelled by [3H]-quipazine in NG108-15 cells. In the anaesthetized, vagotomized micropig, SDZ 205,557 produced only a transient blockade of 5-HT4-mediated tachycardia. This contrasted with tropisetron, which was active for over 60 min after administration. The half-lives for the inhibitory responses of SDZ 205,557 and tropisetron were 23 and 116 min, respectively. 4. In conclusion, SDZ 205,557 has similar affinity for 5-HT3 and 5-HT4 receptors. The apparent selectivity observed in guinea-pig is due to the atypical nature of the 5-HT3 receptor in this species. The short duration of action of this novel antagonist may complicate its use in vivo. SDZ 205,557 should, therefore, be used with appropriate caution in studies defining the 5-HT4 receptor. PMID:8448587

  5. 3,4-Methylenedioxyamphetamine (MDA) analogues exhibit differential effects on synaptosomal release of 3H-dopamine and 3H-5-hydroxytryptamine

    SciTech Connect

    McKenna, D.J.; Guan, X.M.; Shulgin, A.T. )

    1991-03-01

    The effect of various analogues of the neurotoxic amphetamine derivative, MDA (3,4-methylenedioxyamphetamine) on carrier-mediated, calcium-independent release of 3H-5-HT and 3H-DA from rat brain synaptosomes was investigated. Both enantiomers of the neurotoxic analogues MDA and MDMA (3,4-methylenedioxymethamphetamine) induce synaptosomal release of 3H-5-HT and 3H-DA in vitro. The release of 3H-5-HT induced by MDMA is partially blocked by 10(-6) M fluoxetine. The (+) enantiomers of both MDA and MDMA are more potent than the (-) enantiomers as releasers of both 3H-5-HT and 3H-DA. Eleven analogues, differing from MDA with respect to the nature and number of ring and/or side chain substituents, also show some activity in the release experiments, and are more potent as releasers of 3H-5-HT than of 3H-DA. The amphetamine derivatives {plus minus}fenfluramine, {plus minus}norfenfluramine, {plus minus}MDE, {plus minus}PCA, and d-methamphetamine are all potent releasers of 3H-5-HT and show varying degrees of activity as 3H-DA releasers. The hallucinogen DOM does not cause significant release of either 3H-monoamine. Possible long-term serotonergic neurotoxicity was assessed by quantifying the density of 5-HT uptake sites in rats treated with multiple doses of selected analogues using 3H-paroxetine to label 5-HT uptake sites. In the neurotoxicity study of the compounds investigated, only (+)MDA caused a significant loss of 5-HT uptake sites in comparison to saline-treated controls. These results are discussed in terms of the apparent structure-activity properties affecting 3H-monoamine release and their possible relevance to neurotoxicity in this series of MDA congeners.

  6. Prevention of 5-hydroxytryptamine2C receptor RNA editing and alternate splicing in C57BL/6 mice activates the hypothalamic-pituitary-adrenal axis and alters mood

    PubMed Central

    Bombail, Vincent; Qing, Wei; Chapman, Karen E; Holmes, Megan C

    2014-01-01

    The 5-hydroxytryptamine2C (5-HT)2C receptor is widely implicated in the aetiology of affective and eating disorders as well as regulation of the hypothalamo-pituitary-adrenal axis. Signalling through this receptor is regulated by A-to-I RNA editing, affecting three amino acids in the protein sequence, with unedited transcripts encoding a receptor (INI) that, in vitro, is hyperactive compared with edited isoforms. Targeted alteration (knock-in) of the Htr2c gene to generate ‘INI’ mice with no alternate splicing, solely expressing the full-length unedited isoform, did not produce an overt metabolic phenotype or altered anxiety behaviour, but did display reduced depressive-like and fear-associated behaviours. INI mice exhibited a hyperactive hypothalamo-pituitary-adrenal axis, with increased nadir plasma corticosterone and corticotrophin-releasing hormone expression in the hypothalamus but responded normally to chronic stress and showed normal circadian activity and activity in a novel environment. The circadian patterns of 5-HT2C receptor mRNA and mbii52, a snoRNA known to regulate RNA editing and RNA splicing of 5-HT2C receptor pre-mRNA, were altered in INI mice compared with wild-type control mice. Moreover, levels of 5-HT1A receptor mRNA were increased in the hippocampus of INI mice. These gene expression changes may underpin the neuroendocrine and behavioural changes observed in INI mice. However, the phenotype of INI mice was not consistent with a globally hyperactive INI receptor encoded by the unedited transcript in the absence of alternate splicing. Hence, the in vivo outcome of RNA editing may be neuronal cell type specific. PMID:25257581

  7. 5-Hydroxytryptamine 1A receptors in the dorsomedial hypothalamus connected to dorsal raphe nucleus inputs modulate defensive behaviours and mediate innate fear-induced antinociception.

    PubMed

    Biagioni, Audrey Franceschi; de Oliveira, Rithiele Cristina; de Oliveira, Ricardo; da Silva, Juliana Almeida; dos Anjos-Garcia, Tayllon; Roncon, Camila Marroni; Corrado, Alexandre Pinto; Zangrossi, Hélio; Coimbra, Norberto Cysne

    2016-03-01

    The dorsal raphe nucleus (DRN) is an important brainstem source of 5-hydroxytryptamine (5-HT), and 5-HT plays a key role in the regulation of panic attacks. The aim of the present study was to determine whether 5-HT1A receptor-containing neurons in the medial hypothalamus (MH) receive neural projections from DRN and to then determine the role of this neural substrate in defensive responses. The neurotracer biotinylated dextran amine (BDA) was iontophoretically microinjected into the DRN, and immunohistochemical approaches were then used to identify 5HT1A receptor-labelled neurons in the MH. Moreover, the effects of pre-treatment of the dorsomedial hypothalamus (DMH) with 8-OH-DPAT and WAY-100635, a 5-HT1A receptor agonist and antagonist, respectively, followed by local microinjections of bicuculline, a GABAA receptor antagonist, were investigated. We found that there are many projections from the DRN to the perifornical lateral hypothalamus (PeFLH) but also to DMH and ventromedial (VMH) nuclei, reaching 5HT1A receptor-labelled perikarya. DMH GABAA receptor blockade elicited defensive responses that were followed by antinociception. DMH treatment with 8-OH-DPAT decreased escape responses, which strongly suggests that the 5-HT1A receptor modulates the defensive responses. However, DMH treatment with WAY-100635 failed to alter bicuculline-induced defensive responses, suggesting that 5-HT exerts a phasic influence on 5-HT1A DMH neurons. The activation of the inhibitory 5-HT1A receptor had no effect on antinociception. However, blockade of the 5-HT1A receptor decreased fear-induced antinociception. The present data suggest that the ascending pathways from the DRN to the DMH modulate panic-like defensive behaviours and mediate antinociceptive phenomenon by recruiting 5-HT1A receptor in the MH. PMID:26749090

  8. 5-Hydroxytryptamine receptor agonists for the abortive treatment of vascular headaches block mast cell, endothelial and platelet activation within the rat dura mater after trigeminal stimulation.

    PubMed

    Buzzi, M G; Dimitriadou, V; Theoharides, T C; Moskowitz, M A

    1992-06-26

    Antidromic stimulation of small caliber trigeminal axons causes neurogenic inflammation in the dura mater and tongue as evidenced by marked increases in mast cell activation, protein extravasation, as well as in the numbers of endothelial cytoplasmic vesicles, endothelial microvilli and platelet aggregates within ipsilateral post-capillary venules. In this report, we examined the effects of pretreatment with serotonin1 receptor agonists, dihydroergotamine (50 micrograms/kg, i.v.) and sumatriptan (100 micrograms/kg, i.v.) on the light and electron microscopic changes which develop after trigeminal ganglion stimulation. Both dihydroergotamine and sumatriptan are useful in the acute treatment of vascular headaches and bind with high affinity to 5-HT1D receptors. Both drugs decreased significantly the number of dural vessels showing endothelial or platelet changes and the numbers of activated mast cells, but did not affect the neurogenic response in the tongue. The drugs also blocked the accumulation of horseradish peroxidase reaction product within the endothelium and perivascular space on the stimulated side. The receptor is not present on trigeminovascular fibers innervating extracranial cephalic tissues. Drug mechanism probably involves inhibition of a proximal step in the pathophysiological cascade (e.g., via activation of a prejunctional receptor) because (a) receptors for sumatriptan have not been identified on mast cells whereas the inflammatory response was attenuated in mast cells as well as within platelets and the endothelium and (b) previous work indicates that sumatriptan and dihydroergotamine block neurotransmitter release. Hence, constriction of vascular smooth muscle mediated by postjunctional 5-hydroxytryptamine receptors is unlikely to explain the anti-inflammatory actions of dihydroergotamine or sumatriptan reported here.

  9. Functional selectivity of hallucinogenic phenethylamine and phenylisopropylamine derivatives at human 5-hydroxytryptamine (5-HT)2A and 5-HT2C receptors.

    PubMed

    Moya, Pablo R; Berg, Kelly A; Gutiérrez-Hernandez, Manuel A; Sáez-Briones, Patricio; Reyes-Parada, Miguel; Cassels, Bruce K; Clarke, William P

    2007-06-01

    2,5-Dimethoxy-4-substituted phenylisopropylamines and phenethylamines are 5-hydroxytryptamine (serotonin) (5-HT)(2A/2C) agonists. The former are partial to full agonists, whereas the latter are partial to weak agonists. However, most data come from studies analyzing phospholipase C (PLC)-mediated responses, although additional effectors [e.g., phospholipase A(2) (PLA(2))] are associated with these receptors. We compared two homologous series of phenylisopropylamines and phenethylamines measuring both PLA(2) and PLC responses in Chinese hamster ovary-K1 cells expressing human 5-HT(2A) or 5-HT(2C) receptors. In addition, we assayed both groups of compounds as head shake inducers in rats. At the 5-HT(2C) receptor, most compounds were partial agonists for both pathways. Relative efficacy of some phenylisopropylamines was higher for both responses compared with their phenethylamine counterparts, whereas for others, no differences were found. At the 5-HT(2A) receptor, most compounds behaved as partial agonists, but unlike findings at 5-HT(2C) receptors, all phenylisopropylamines were more efficacious than their phenethylamine counterparts. 2,5-Dimethoxyphenylisopropylamine activated only the PLC pathway at both receptor subtypes, 2,5-dimethoxyphenethylamine was selective for PLC at the 5-HT(2C) receptor, and 2,5-dimethoxy-4-nitrophenethylamine was PLA(2)-specific at the 5-HT(2A) receptor. For both receptors, the rank order of efficacy of compounds differed depending upon which response was measured. The phenylisopropylamines were strong head shake inducers, whereas their phenethylamine congeners were not, in agreement with in vitro results and the involvement of 5-HT(2A) receptors in the head shake response. Our results support the concept of functional selectivity and indicate that subtle changes in ligand structure can result in significant differences in the cellular signaling profile.

  10. The 5-hydroxytryptamine1A receptor agonist, (+)-8-hydroxy-2-(di-n-propylamino)-tetralin, increases cardiac output and renal perfusion in rats subjected to hypovolemic shock.

    PubMed

    Tiniakov, Ruslan; Osei-Owusu, Patrick; Scrogin, Karie E

    2007-02-01

    The 5-hydroxytryptamine(1A) receptor agonist, (+)-8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT), raises blood pressure (BP) and venous tone in rats subjected to hemorrhagic shock. Here, BP, ascending aortic blood flow [i.e., estimate of cardiac output (CO)] and venous blood gases were measured to determine the hemodynamic effects of 8-OH-DPAT (30 nmol/kg i.v., n = 10), saline (n = 10), or an equipressor infusion of epinephrine (n = 10) in unanesthetized rats subjected to hemorrhagic shock (25 min of hypotensive hemorrhage, approximately 50 mm Hg). Renal and iliac blood flow were measured in separate groups of similarly hemorrhaged rats given the same dose of 8-OH-DPAT (n = 7) or saline (n = 6). Compared with saline treatment, 8-OH-DPAT produced a sustained rise in BP (+32 +/- 4 versus +9 +/- 2 mm Hg, 15 min after injection, P < 0.01) and CO (+27 +/- 5 versus +4 +/- 6 ml/min/kg, P < 0.01) but did not affect total peripheral resistance (TPR). Infusion of epinephrine reduced CO (-12 +/- 6 ml/min/kg, P < 0.01) and dramatically increased TPR [+0.37 +/- 0.11 versus +0.05 +/- 0.05 log (mm Hg/ml/min/kg), P < 0.01]. 8-OH-DPAT increased renal conductance (+7 +/- 1 versus +4 +/- 1 microl/min/mm Hg, P < 0.01) but did not significantly affect iliac conductance. 8-OH-DPAT attenuated further development of acidosis compared with either saline or epinephrine (-5.6 +/- 1.6 versus -13.0 +/- 2.0 versus -11.3 +/- 2.6 mmol/liter base excess 45 min after start of hemorrhage, both P < 0.01 versus 8-OH-DPAT). These data demonstrate that 8-OH-DPAT improves hemodynamics during circulatory shock, in part, through renal vasodilation and mobilizing of blood stores.

  11. Selective Recognition of 5-Hydroxytryptamine and Dopamine on a Multi-Walled Carbon Nanotube-Chitosan Hybrid Film-Modified Microelectrode Array

    PubMed Central

    Xu, Huiren; Wang, Li; Luo, Jinping; Song, Yilin; Liu, Juntao; Zhang, Song; Cai, Xinxia

    2015-01-01

    It is difficult to determine dopamine (DA) and 5-hydroxytryptamine (5-HT) accurately because of the interference of ascorbic acid (AA) in vitro, which has a high concentration and can be oxidized at a potential close to DA and 5-HT at a conventional electrode, combined with the overlapping voltammetric signal of DA and 5-HT at a bare electrode. Herein, chitosan (CS) was used as a stabilizing matrix by electrochemical reaction, and multi-walled carbon nanotubes (MWCNTs) were modified onto the microelectrode array (MEA). The CS-MWCNT hybrid film-modified MEA was quite effective at simultaneously recognizing these species in a mixture and resolved the overlapping anodic peaks of AA, DA and 5-HT into three well-defined oxidation peaks in differential pulse voltammetry (DPV) at −80 mV, 105 mV and 300 mV (versus Ag|AgCl), respectively. The linear responses were obtained in the range of 5 × 10−6 M to 2 × 10−4 M for DA (r = 0.996) and in the range of 1 × 10−5 M to 3 × 10−4 M for 5-HT (r = 0.999) using the DPV under the presence of a single substance. While DA coexisted with 5-HT in the interference of 3 × 10−4 M AA, the linear responses were obtained in the range of 1 × 10−5 M to 3 × 10−4 M for selective molecular recognition of DA (r = 0.997) and 5-HT (r = 0.997) using the DPV. Therefore, this proposed MEA was successfully used for selective molecular recognition and determination of DA and 5-HT using the DPV, which has a potential application for real-time determination in vitro experiments. PMID:25580900

  12. Medial hypothalamic 5-hydroxytryptamine (5-HT)1A receptors regulate neuroendocrine responses to stress and exploratory locomotor activity: application of recombinant adenovirus containing 5-HT1A sequences.

    PubMed

    Li, Qian; Holmes, Andrew; Ma, Li; Van de Kar, Louis D; Garcia, Francisca; Murphy, Dennis L

    2004-12-01

    Our previous studies found that serotonin transporter (SERT) knock-out mice showed increased sensitivity to minor stress and increased anxiety-like behavior but reduced locomotor activity. These mice also showed decreased density of 5-hydroxytryptamine (5-HT1A) receptors in the hypothalamus, amygdala, and dorsal raphe. To evaluate the contribution of hypothalamic 5-HT1A receptors to these phenotypes of SERT knock-out mice, two studies were conducted. Recombinant adenoviruses containing 5-HT1A sense and antisense sequences (Ad-1AP-sense and Ad-1AP-antisense) were used to manipulate 5-HT1A receptors in the hypothalamus. The expression of the 5-HT1A genes is controlled by the 5-HT1A promoter, so that they are only expressed in 5-HT1A receptor-containing cells. (1) Injection of Ad-1AP-sense into the hypothalamus of SERT knock-out mice restored 5-HT1A receptors in the medial hypothalamus; this effect was accompanied by elimination of the exaggerated adrenocorticotropin responses to a saline injection (minor stress) and reduced locomotor activity but not by a change in increased exploratory anxiety-like behavior. (2) To further confirm the observation in SERT-/- mice, Ad-1AP-antisense was injected into the hypothalamus of normal mice. The density and the function of 5-HT1A receptors in the medial hypothalamus were significantly reduced in Ad-1AP-antisense-treated mice. Compared with the control group (injected with Ad-track), Ad-1A-antisense-treated mice showed a significant reduction in locomotor activity, but again no changes in exploratory anxiety-like behaviors, tested by elevated plus-maze and open-field tests. Thus, the present results demonstrate that medial hypothalamic 5-HT1A receptors regulate stress responses and locomotor activity but may not regulate exploratory anxiety-like behaviors. PMID:15574737

  13. Ionotrophic 5-hydroxytryptamine type 3 receptor activates the protein kinase C-dependent phospholipase D pathway in human T-cells.

    PubMed Central

    Khan, N A; Hichami, A

    1999-01-01

    The present study was undertaken to investigate the role of the 5-hydroxytryptamine (5-HT) ionotrophic receptor 5-HT(3) in the activation of human Jurkat T-cells. 5-HT and 2-methyl-5-HT (2Me-5-HT), an agonist of the 5-HT(3) receptor, induced increases in intracellular free Na(+) concentrations, [Na(+)](i), via opening of the ionotrophic receptor in these cells. These two serotonergic (5-hydroxytryptaminergic) agents potentiated phytohaemagglutinin (PHA)-induced T-cell activation. However, they failed to potentiate dioctanoglycerol-plus-ionomycin-stimulated T-cell blastogenesis. Interestingly, an inhibitor of protein kinase C (PKC), GF 109203X, curtailed significantly 5-HT and 2Me-5-HT-potentiated T-cell activation. These results demonstrate that the opening of the 5-HT(3) ionotrophic receptor is implicated in T-cell activation via the PKC pathway. Furthermore, 5-HT and 2Me-5-HT stimulated phospholipase D (PLD) activity, as measured by the production of phosphatidylethanol and phosphatidylbutanol at the expense of phosphatidic acid (PA). GF 109203X significantly curtailed the 5-HT- and 2Me-5-HT-induced PLD activity and T-cell activation. The PLD/PA pathway stimulated by these two serotonergic agents resulted in the production of 1,2-diacylglycerol (DAG) mass in Jurkat T-cells. These results altogether suggest that 5-HT and 2Me-5-HT potentiate T-cell activation via increases in [Na(+)](i) and the activation of the PKC-dependent PLD pathway. PMID:10548551

  14. Ionotrophic 5-hydroxytryptamine type 3 receptor activates the protein kinase C-dependent phospholipase D pathway in human T-cells.

    PubMed

    Khan, N A; Hichami, A

    1999-11-15

    The present study was undertaken to investigate the role of the 5-hydroxytryptamine (5-HT) ionotrophic receptor 5-HT(3) in the activation of human Jurkat T-cells. 5-HT and 2-methyl-5-HT (2Me-5-HT), an agonist of the 5-HT(3) receptor, induced increases in intracellular free Na(+) concentrations, [Na(+)](i), via opening of the ionotrophic receptor in these cells. These two serotonergic (5-hydroxytryptaminergic) agents potentiated phytohaemagglutinin (PHA)-induced T-cell activation. However, they failed to potentiate dioctanoglycerol-plus-ionomycin-stimulated T-cell blastogenesis. Interestingly, an inhibitor of protein kinase C (PKC), GF 109203X, curtailed significantly 5-HT and 2Me-5-HT-potentiated T-cell activation. These results demonstrate that the opening of the 5-HT(3) ionotrophic receptor is implicated in T-cell activation via the PKC pathway. Furthermore, 5-HT and 2Me-5-HT stimulated phospholipase D (PLD) activity, as measured by the production of phosphatidylethanol and phosphatidylbutanol at the expense of phosphatidic acid (PA). GF 109203X significantly curtailed the 5-HT- and 2Me-5-HT-induced PLD activity and T-cell activation. The PLD/PA pathway stimulated by these two serotonergic agents resulted in the production of 1,2-diacylglycerol (DAG) mass in Jurkat T-cells. These results altogether suggest that 5-HT and 2Me-5-HT potentiate T-cell activation via increases in [Na(+)](i) and the activation of the PKC-dependent PLD pathway.

  15. Emetic responses to T-2 toxin, HT-2 toxin and emetine correspond to plasma elevations of peptide YY3-36 and 5-hydroxytryptamine.

    PubMed

    Wu, Wenda; Zhou, Hui-Ren; Bursian, Steven J; Link, Jane E; Pestka, James J

    2016-04-01

    Trichothecene mycotoxins are a family of potent translational inhibitors that are associated with foodborne outbreaks of human and animal gastroenteritis in which vomiting is a clinical hallmark. Deoxynivalenol (DON, vomitoxin) and other Type B trichothecenes have been previously demonstrated to cause emesis in the mink (Neovison vison), and this response has been directly linked to secretion of both the satiety hormone peptide YY3-36 (PYY3-36) and neurotransmitter 5-hydroxytryptamine (5-HT). Here, we characterized the emetic responses in the mink to T-2 toxin (T-2) and HT-2 toxin (HT-2), two highly toxic Type A trichothecenes that contaminate cereals, and further compared these effects to those of emetine, a natural alkaloid that is used medicinally and also well known to block translation and cause vomiting. Following intraperitoneal (IP) and oral exposure, all three agents caused vomiting with evident dose-dependent increases in both duration and number of emetic events as well as decreases in latency to emesis. T-2 and HT-2 doses causing emesis in 50 % of treated animals (ED50s) were 0.05 and 0.02 mg/kg BW following IP and oral administration, respectively, whereas the ED50s for emetine were 2.0 and 1.0 mg/kg BW for IP and oral exposure, respectively. Importantly, oral administration of all three toxins elicited marked elevations in plasma concentrations of PYY3-36 and 5-HT that corresponded to emesis. Taken together, the results suggest that T-2 and HT-2 were much more potent than emetine and that emesis induction by all three translational inhibitors co-occurred with increases in circulating levels of PYY3-36 and 5-HT.

  16. Sucrose preload reduces snacking after mild mental stress in healthy participants as a function of 5-hydroxytryptamine transporter gene promoter polymorphism.

    PubMed

    Markus, C Rob; Jonkman, Lisa M; Capello, Aimee; Leinders, Sacha; Hüsch, Fabian

    2015-01-01

    Brain serotonin (5-hydroxytryptamine, 5-HT) dysfunction is considered to promote food intake and eating-related disturbances, especially under stress or negative mood. Vulnerability for 5-HT disturbances is considered to be genetically determined, including a short (S) allele polymorphism in the serotonin transporter gene (5-HTTLPR) that is associated with lower serotonin function. Since 5-HT function may be slightly increased by carbohydrate consumption, S-allele 5-HTTLPR carriers in particular may benefit from a sugar-preload due to their enhanced 5-HT vulnerability. The aim of the current study was to investigate whether a sugar-containing preload may reduce appetite and energy intake after exposure to stress to induce negative mood, depending on genetic 5-HT vulnerability. From a population of 771 healthy young male and female genotyped college students 31 S/S carriers (8 males, 23 females) and 26 long allele (L/L) carriers (9 males, 17 females) (mean ± S.D. 22 ± 1.6 years; body mass index, BMI, 18-33 kg/m(2)) were monitored for changes in appetite and snacking behavior after stress exposure. Results revealed an increased energy intake after mild mental stress (negative mood) mainly for high-fat sweet foods, which was significantly greater in S/S carriers, and only in these genotypes this intake was significantly reduced by a sucrose-containing preload. Although alternative explanations are possible, it is suggested that S/S participants may have enhanced brain (hypothalamic) 5-HT responsiveness to food that makes them more susceptible to the beneficial satiation effects of a sucrose-preload as well as to the negative effects of mild mental stress on weight gain.

  17. [Methoxyflurane and ethanol do not inhibit the neuronal uptake of noradrenaline (uptake 1) at the desipramine binding site].

    PubMed

    Kress, H G; Schömig, E

    1990-07-01

    We recently demonstrated that the net accumulation of 3H-norepinephrine in the rat pheochromocytoma cell line PC12 was reduced by anesthetic concentrations of n-alkanols and the volatile anesthetics halothane, enflurane, isoflurane, and methoxyflurane. In PC12 cells, as in adrenergic neurons, norepinephrine is transported across the plasma membrane by a saturable, high-affinity, carrier-mediated mechanism (uptake1), which follows Michaelis-Menten kinetics, is energy- and sodium-dependent, and is inhibited by low concentrations of cocaine and the tricyclic antidepressant desipramine. Although uptake1 is the most important process for the removal of norepinephrine from the synaptic cleft, the net accumulation of norepinephrine within the neuron also depends on other factors including its vesicular uptake and storage within the granules, its metabolism by monoamine oxidase (MAO) and catechol-O-methyltransferase (COMT), and the efflux of its more lipophilic metabolites. In our previous report we could not exclude the contribution of any of these factors to the observed inhibitory effects of volatile substances. Therefore, the aim of the present study with ethanol and methoxyflurane was: (1) to elucidate further the exact mechanism responsible for the reduction of the norepinephrine accumulation; and (2) to investigate the anesthetics' interaction with the substrate recognition site, which is identical with the desipramine binding site on the norepinephrine carrier. METHODS. For 3H-norepinephrine uptake experiments, PC12 cells were cultured on dishes (60 mm, Nunc) coated with polyornithine. Reserpine (10 microM) was added to the culture 24 h before the experiment to deplete endogenous norepinephrine. The initial carrier-mediated transport rate (60 s) was measured as previously described. 3H-desipramine equilibrium binding was determined with isolated plasma membranes prepared from PC12 cells grown in suspension culture. The carrier-mediated uptake of 3H

  18. Autoradiographic localization of adenosine uptake sites in rat brain using (/sup 3/H)nitrobenzylthioinosine

    SciTech Connect

    Bisserbe, J.C.; Patel, J.; Marangos, P.J.

    1985-02-01

    The adenosine uptake site has been localized in rat brain by an in vitro light microscopic autoradiographic method, using (/sup 3/H)nitrobenzylthioinosine ((/sup 3/H)NBI) as the probe. The binding characteristics of (/sup 3/H)NBI on slide-mounted sections are comparable to those seen in studies performed on brain homogenates. A very high density of uptake sites occurs in the nucleus tractus solitarius, in the superficial layer of the superior colliculus, in several thalamic nuclei, and also in geniculate body nuclei. A high density of sites are also observed in the nucleus accumbens, the caudate putamen, the dorsal tegmentum area, the substantia nigra, and the central gray. The localization of the adenosine uptake site in brain may provide information on the functional activity of the site and suggests the involvement of the adenosine system in the central regulation of cardiovascular function.

  19. Diabetes-induced changes in the 5-hydroxytryptamine inhibitory receptors involved in the pressor effect elicited by sympathetic stimulation in the pithed rat.

    PubMed

    García, Mónica; Morán, Asunción; Calama, Elena; Martín, Maria Luisa; Barthelmebs, Mariette; Román, Luis San

    2005-07-01

    1. We investigated the effect of alloxan-induced diabetes on the inhibitory mechanisms of 5-hydroxytryptamine (5-HT) in the pressor responses induced by stimulation of sympathetic vasopressor outflow in pithed rats, and analysed the type and/or subtype of 5-HT receptors involved. 2. Diabetes was induced in male Wistar rats by a single s.c. injection of alloxan, then 4 weeks later, they were anaesthetized, pretreated with atropine and pithed. Electrical stimulation of the sympathetic outflow from the spinal cord (0.1, 0.5, 1 and 5 Hz) resulted in frequency-dependent increases in blood pressure. 3. Intravenous infusions of 5-HT (1-80 microg kg(-1) min(-1)) reduced the pressor effects obtained by electrical stimulation. The 5-HT(1) receptor agonist 5-carboxamidotryptamine, 5-CT (5 microg kg(-1) min(-1)), caused an inhibition of the pressor response, whereas the selective 5-HT(2) receptor agonist, alpha-methyl-5-HT (5 microg kg(-1) min(-1)) and the selective 5-HT(3) receptor agonist, 1-phenylbiguanide (40 microg kg(-1) min(-1)), did not modify the sympathetic pressor responses. 5-HT had no effect on exogenous noradrenaline (NA)-induced pressor responses. 4. The inhibition of electrically induced pressor responses by 5-HT (10 microg kg(-1) min(-1)) was unable to be elicited after i.v. treatment with methiothepin (100 microg kg(-1)) because of the marked inhibition produced by methiothepin alone. The 5-HT-induced inhibition was blocked after i.v. administration of WAY-100,635 (100 microg kg(-1)) and not affected by ritanserin (1 mg kg(-1)), MDL 72222 (2 mg kg(-1)). 5. The selective 5-HT(1A) receptor agonist, 8-hydroxydipropylaminotretalin hydrobromide (8-OH-DPAT) (5-20 microg kg(-1) min(-1)) but neither the rodent 5-HT(1B) receptor agonist, CGS-12066B (5 microg kg(-1) min(-1)), nor the selective nonrodent 5-HT(1B) and 5-HT(1D) receptor agonist, L-694,247 (5 and 40 microg kg(-1) min(-1)), inhibited the electrically induced pressor response. The selective 5-HT(1A) receptor

  20. 5-Hydroxytryptamine(1F) receptors do not participate in vasoconstriction: lack of vasoconstriction to LY344864, a selective serotonin(1F) receptor agonist in rabbit saphenous vein.

    PubMed

    Cohen, M L; Schenck, K

    1999-09-01

    Recently, several novel approaches to the treatment of migraine have been advanced, including selective 5-hydroxytryptamine (or serotonin) 1B/1D (5-HT(1B/1D)) receptor agonists such as sumatriptan and 5-HT(1F) receptor agonists such as LY344864. Many 5-HT(1B/1D) receptor agonists have been identified based on their ability to produce cerebral vascular contraction, whereas LY344864 was identified as an inhibitor of trigeminal nerve-mediated dural extravasation. In our study, several triptan derivatives were compared with LY344864 for their ability to contract the rabbit saphenous vein, a tissue used in the preclinical identification of sumatriptan-related agonists. Sumatriptan, zolmitriptan, rizatriptan, and naratriptan all contracted the rabbit saphenous vein from baseline tone, whereas LY344864 in concentrations up to 10(-4) M did not contract the rabbit saphenous vein. Furthermore, vascular contractions to sumatriptan were markedly augmented in the presence of prostaglandin F(2alpha) (PGF(2alpha)). However, even in the presence of PGF(2alpha) (3 x 10(-7) M), LY344864 did not contract the rabbit saphenous vein in concentrations well in excess of its 5-HT(1F) receptor affinity (pK(i) = 8.2). Only when concentrations exceeded those likely to activate 5-HT(1B) and 5-HT(1D) receptors (>10(-5) M) did modest contractile responses occur in the presence of PGF(2alpha). Use of these serotonergic agonists revealed a significant correlation between the contractile potency in the rabbit saphenous vein and the affinities of these agonists at 5-HT(1B) and 5-HT(1D) receptors, although contractile agonist potencies were not quantitatively similar to 5-HT(1B) or 5-HT(1D) receptor affinities. In contrast, no significant correlation existed between the contractile potencies of these serotonergic agonists in the rabbit saphenous vein and their affinity at 5-HT(1F) receptors. These data support the contention that activation of 5-HT(1F) receptors will not result in vascular

  1. Localization of serotoni (5-hydroxytryptamine, 5-HT) with partial purification and characterization of a serotonin binding protein in the intestinal tissue of the nematode Ascaris suum

    SciTech Connect

    Martin, R.E.

    1989-01-01

    An intracellular 5-HT binding protein (SBP) from intestinal tissue was partially purified and characterized. Binding of ({sup 3}H) 5-HT to the protein appeared to be Fe{sup +2}-sensitive and maximal (20.8pmol/mg protein) at 5 {times} 10{sup {minus}4}M Fe{sup +2} and 10{sup {minus}7}M ({sup 3}H) 5-HT. There were two 5-HT binding sites present at optimum Fe{sup +2} concentrations. The Bmax values of these sites were more sensitive to Fe{sup +2} than Kd values. Sulfhydryl reducing agents, cation chelators, Fe{sup +3}, Ca{sup +2} and antagonists of 5-HT uptake and storage inhibited binding of 5-HT to SBP. Gel exclusion chromatography indicated the presence of a 45Kda SBP that in 5 {times} 10{sup {minus}5}M Fe{sup +2} may form aggregates ranging in size from approximately 80 to >1000Kda. The data indicate these in vitro aggregates may correspond to the electron-opaque patches observed in situ. Ascaris suum may provide a model system to further elucidate the physiological role of analogous serotonin binding proteins that have been identified in mammalian systems.

  2. Dopamine uptake sites in the striatum are distributed differentially in striosome and matrix compartments

    SciTech Connect

    Graybiel, A.M.; Moratalla, R. )

    1989-11-01

    A major mechanism of neurotransmitter inactivation at catecholaminergic synapses in reuptake of released transmitter at high-affinity uptake sites on presynaptic terminals. The authors have analyzed the anatomical distribution of site-selective ligand binding for dopamine uptake sites in the striatum of rat, cat, and monkey. The authors report here that desipramine-sensitive ({sup 3}H)mazindol binding sites have highly heterogeneous distributions in the dorsal and the ventral striatum. In the caudate nucleus of cat and monkey, ({sup 3}H)mazindol binding observes striosomal ordering, being reduced in striosomes and heightened in the extrastriosomal matrix. Some local heterogeneity appears in the ventral caudoputamen of the rat. Different subdivisions of the nucleus accumbens also have different binding levels. These findings suggest that some functional effects of psychoactive drugs, such as cocaine, and that bind to the dopamine-uptake complex could be related to the distribution of these specific uptake sites. The findings also raise the possibility that these distributions could result in selective neuronal vulnerability to neurotoxins, such as 1-methyl-4-phenylpyridine (MPP{sup +}), that depend on the dopamine-uptake complex for entry into neurons.

  3. Diabetes-induced changes in the 5-hydroxytryptamine inhibitory receptors involved in the pressor effect elicited by sympathetic stimulation in the pithed rat

    PubMed Central

    García, Mónica; Morán, Asunción; Calama, Elena; Martín, Maria Luisa; Barthelmebs, Mariette; Román, Luis San

    2005-01-01

    We investigated the effect of alloxan-induced diabetes on the inhibitory mechanisms of 5-hydroxytryptamine (5-HT) in the pressor responses induced by stimulation of sympathetic vasopressor outflow in pithed rats, and analysed the type and/or subtype of 5-HT receptors involved. Diabetes was induced in male Wistar rats by a single s.c. injection of alloxan, then 4 weeks later, they were anaesthetized, pretreated with atropine and pithed. Electrical stimulation of the sympathetic outflow from the spinal cord (0.1, 0.5, 1 and 5 Hz) resulted in frequency-dependent increases in blood pressure. Intravenous infusions of 5-HT (1–80 μg kg−1 min−1) reduced the pressor effects obtained by electrical stimulation. The 5-HT1 receptor agonist 5-carboxamidotryptamine, 5-CT (5 μg kg−1 min−1), caused an inhibition of the pressor response, whereas the selective 5-HT2 receptor agonist, α-methyl-5-HT (5 μg kg−1 min−1) and the selective 5-HT3 receptor agonist, 1-phenylbiguanide (40 μg kg−1 min−1), did not modify the sympathetic pressor responses. 5-HT had no effect on exogenous noradrenaline (NA)-induced pressor responses. The inhibition of electrically induced pressor responses by 5-HT (10 μg kg−1 min−1) was unable to be elicited after i.v. treatment with methiothepin (100 μg kg−1) because of the marked inhibition produced by methiothepin alone. The 5-HT-induced inhibition was blocked after i.v. administration of WAY-100,635 (100 μg kg−1) and not affected by ritanserin (1 mg kg−1), MDL 72222 (2 mg kg−1). The selective 5-HT1A receptor agonist, 8-hydroxydipropylaminotretalin hydrobromide (8-OH-DPAT) (5–20 μg kg−1 min−1) but neither the rodent 5-HT1B receptor agonist, CGS-12066B (5 μg kg−1 min−1), nor the selective nonrodent 5-HT1B and 5-HT1D receptor agonist, L-694,247 (5 and 40 μg kg−1 min−1), inhibited the electrically induced pressor response. The selective 5-HT1A

  4. The highly selective 5-hydroxytryptamine (5-HT)2A receptor antagonist, EMD 281014, significantly increases swimming and decreases immobility in male congenital learned helpless rats in the forced swim test.

    PubMed

    Patel, Jignesh G; Bartoszyk, Gerd D; Edwards, Emmeline; Ashby, Charles R

    2004-04-01

    We examined the effect of the highly selective 5-hydroxytryptamine (5-HT)(2A) receptor antagonist 7-[4-[2-(4-fluoro-phenyl)-ethyl]-piperazine-1-carbonyl]-1H-indole-3-carbonitrile HCl (EMD 281014) in congenital learned helpless male rats in the forced swim test. The administration of EMD-281014 (0.3-30 mg/kg i.p.) to congenital learned helpless rats dose-dependently and significantly (at 10 and 30 mg/kg) decreased immobility and increased swimming compared to vehicle-treated animals. Thus, EMD 281014 produces effects in the forced swim test resembling those of antidepressants.

  5. An overview of muscle glucose uptake during exercise. Sites of regulation.

    PubMed

    Wasserman, D H; Halseth, A E

    1998-01-01

    The uptake of blood glucose by skeletal muscle is a complex process. In order to be metabolized, glucose must travel the path from blood to interstitium to intracellular space and then be phosphorylated to glucose 6-phosphate (G6P). Movement of glucose from blood to interstitium is determined by skeletal muscle blood flow, capillary recruitment and the endothelial permeability to glucose. The influx of glucose from the interstitium to intracellular space is determined by the number of glucose transporters in the sarcolemma and the glucose gradient across the sarcolemma. The capacity to phosphorylate glucose is determined by the amount of skeletal muscle hexokinase II, hexokinase II compartmentalization within the cell, and the concentration of the hexokinase II inhibitor G6P. Any change in glucose uptake occurs due to an alteration in one or more of these steps. Based on the low calculated intracellular glucose levels and the higher affinity of glucose for phosphorylation relative to transport, glucose transport is generally considered rate-determining for basal muscle glucose uptake. Exercise increases both the movement of glucose from blood to sarcolemma and the permeability of the sarcolemma to glucose. Whether the ability to phosphorylate glucose is increased in the working muscle remains to be clearly shown. It is possible that the accelerated glucose delivery and transport rates during exercise bias regulation so that muscle glucose phosphorylation exerts more control on muscle glucose uptake. Conditions that alter glucose uptake during exercise, such as increased NEFA concentrations, decreased oxygen availability and adrenergic stimulation, must work by altering one or more of the three steps involved in glucose uptake. This review describes the regulation of glucose uptake during exercise at each of these sites under a number of conditions, as well as describing muscle glucose uptake in the post-exercise state.

  6. Specific uptake of serotonin by murine lymphoid cells

    SciTech Connect

    Jackson, J.C.; Walker, R.F.; Brooks, W.H.; Roszman, T.L.

    1986-03-01

    Recently the authors confirmed and extended earlier observations that serotonin (5-hydroxytryptamine, 5HT) can influence immune function. Both 5HT and its precursor, 5-hydroxytryptophan inhibit the primary, in vivo antibody response to sheep red blood cells, in mice. Here, the authors report specific in vitro association of this amine with mouse splenocytes. Spleen cells from 6-8 week old CBA/J mice incorporated /sup 3/H-5HT(10/sup -8/ to 2.5 x 10/sup -6/M) in a saturable manner, at 37/sup 0/C. Specificity of uptake was indicated by competition with excess (10/sup -5/M) unlabelled 5HT and with 10/sup -5/M fluoxetine, a selective inhibitor of active 5HT reuptake in rat brain. The 5HT receptor antagonists, methysergide and cyproheptadine, also blocked 5HT uptake. Cell lysis and displacement studies revealed largely intracellular accumulation of /sup 3/H-5HT with little membrane association, in splenocytes. Hofstee analysis of uptake kinetics yielded an apparent Km of 0.82 +/- 0.22 x 10/sup -7/M and Vmax of 501 +/- 108 pM/3 x 10/sup 6/ cells/10 min. Spleen cells fractionated on Sephadex G10 showed virtually no specific 5HT uptake while peritoneal exudate cells from thioglycollate treated mice displayed 5HT uptake kinetics similar to those of splenocytes. The site of specific /sup 3/H-5HT incorporation within a population of spleen cells and the functional significance of this phenomenon to immunomodulation by 5HT remain to be elucidated.

  7. Autoradiographic localization of /sup 3/H-paroxetine-labeled serotonin uptake sites in rat brain

    SciTech Connect

    De Souza, E.B.; Kuyatt, B.L.

    1987-01-01

    Paroxetine is a potent and selective inhibitor of serotonin uptake into neurons. Serotonin uptake sites have been identified, localized, and quantified in rat brain by autoradiography with 3H-paroxetine; 3H-paroxetine binding in slide-mounted sections of rat forebrain was of high affinity (KD = 10 pM) and the inhibition affinity constant (Ki) values of various drugs in competing 3H-paroxetine binding significantly correlated with their reported potencies in inhibiting synaptosomal serotonin uptake. Serotonin uptake sites labeled by 3H-paroxetine were highly concentrated in the dorsal and median raphe nuclei, central gray, superficial layer of the superior colliculus, lateral septal nucleus, paraventricular nucleus of the thalamus, and the islands of Calleja. High concentrations of 3H-paroxetine binding sites were found in brainstem areas containing dopamine (substantia nigra and ventral tegmental area) and norepinephrine (locus coeruleus) cell bodies. Moderate concentrations of 3H-paroxetine binding sites were present in laminae I and IV of the frontal parietal cortex, primary olfactory cortex, olfactory tubercle, regions of the basal ganglia, septum, amygdala, thalamus, hypothalamus, hippocampus, and some brainstem areas including the interpeduncular, trigeminal, and parabrachial nuclei. Lower densities of 3H-paroxetine binding sites were found in other regions of the neocortex and very low to nonsignificant levels of binding were present in white matter tracts and in the cerebellum. Lesioning of serotonin neurons with 3,4-methylenedioxyamphetamine caused large decreases in 3H-paroxetine binding. The autoradiographic distribution of 3H-paroxetine binding sites in rat brain corresponds extremely well to the distribution of serotonin terminals and cell bodies as well as with the pharmacological sites of action of serotonin.

  8. Native Plant Uptake Model for Radioactive Waste Disposal Areas at the Nevada Test Site

    SciTech Connect

    BROWN,THERESA J.; WIRTH,SHARON

    1999-09-01

    This report defines and defends the basic framework, methodology, and associated input parameters for modeling plant uptake of radionuclides for use in Performance Assessment (PA) activities of Radioactive Waste Management Sites (RWMS) at the Nevada Test Site (NTS). PAs are used to help determine whether waste disposal configurations meet applicable regulatory standards for the protection of human health, the environment, or both. Plants adapted to the arid climate of the NTS are able to rapidly capture infiltrating moisture. In addition to capturing soil moisture, plant roots absorb nutrients, minerals, and heavy metals, transporting them within the plant to the above-ground biomass. In this fashion, plant uptake affects the movement of radionuclides. The plant uptake model presented reflects rooting characteristics important to plant uptake, biomass turnover rates, and the ability of plants to uptake radionuclides from the soil. Parameters are provided for modeling plant uptake and estimating surface contaminant flux due to plant uptake under both current and potential future climate conditions with increased effective soil moisture. The term ''effective moisture'' is used throughout this report to indicate the soil moisture that is available to plants and is intended to be inclusive of all the variables that control soil moisture at a site (e.g., precipitation, temperature, soil texture, and soil chemistry). Effective moisture is a concept used to simplify a number of complex, interrelated soil processes for which there are too little data to model actual plant available moisture. The PA simulates both the flux of radionuclides across the land surface and the potential dose to humans from that flux. Surface flux is modeled here as the amount of soil contamination that is transferred from the soil by roots and incorporated into aboveground biomass. Movement of contaminants to the surface is the only transport mechanism evaluated with the model presented here

  9. Distribution of 3H-GABA uptake sites in the nematode Ascaris

    SciTech Connect

    Guastella, J.; Stretton, A.O. )

    1991-05-22

    The distribution of uptake sites for the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) in the nematode Ascaris suum was examined by autoradiography of 3H-GABA uptake. Single neural processes in both the ventral and dorsal nerve cords were labeled with 3H-GABA. Serial section analysis identified the cells of origin of these processes as the RMEV-like and RMED-like neurons. These cells belong to a set of four neurons in the nerve ring, all of which are labeled by 3H-GABA. 3H-GABA labeling of at least two other sets of cephalic neurons was seen. One of these pairs consists of medium-sized lateral ganglia neurons, located at the level of the amphid commissure bundle. A second pair is located in the lateral ganglia at the level of the deirid commissure bundle. The position and size of these lateral ganglia cells suggest that they are the GABA-immunoreactive lateral ganglia cells frequently seen in whole-mount immunocytochemical preparations. Four neuronal cell bodies located in the retrovesicular ganglion were also labeled with 3H-GABA. These cells, which are probably cholinergic excitatory motor neurons, do not contain detectable GABA-like immunoreactivity. Heavy labeling of muscle cells was also observed. The ventral and dorsal nerve cord inhibitory motor neurons, which are known to contain GABA-like immunoreactivity, were not labeled above background with 3H-GABA. Together with the experiments reported previously, these results define three classes of GABA-associated neurons in Ascaris: (1) neurons that contain endogenous GABA and possess a GABA uptake system; (2) neurons that contain endogenous GABA, but that either lack a GABA uptake system or possess a GABA uptake system of low activity; (3) neurons that possess a GABA uptake system, but that lack endogenous GABA.

  10. Rates and tissue sites of non-insulin- and insulin-mediated glucose uptake in humans

    SciTech Connect

    Baron, A.D.; Brechtel, G.; Wallace, P.; Edelman, S.V.

    1988-12-01

    In vivo glucose uptake can occur via two mechanisms, namely, insulin-mediated glucose uptake (IMGU) and non-insulin-mediated glucose uptake (NIMGU). Although the principal tissue sites for IMGU are skeletal muscle, the tissue sites for NIMGU at a given serum glucose concentration are not known. To examine this issue, rates of whole body glucose uptake (Rd) were measured at basal and during glucose clamp studies performed at euglycemia (approximately 90 mg/dl) and hyperglycemia (approximately 220 mg/dl) in six lean healthy men. Studies were performed during hyperinsulinemia (approximately 70 microU/ml) and during somatostatin-induced insulinopenia to measure IMGU and NIMGU, respectively. During each study, leg glucose balance (arteriovenous catheter technique) was also measured. With this approach, rates of whole body skeletal muscle IMGU and NIMGU can be estimated, and the difference between overall Rd and skeletal muscle glucose uptake represents non-skeletal muscle Rd. The results indicate that approximately 20% of basal Rd is into skeletal muscle. During insulinopenia approximately 86% of body NIMGU occurs in non-skeletal muscle tissues at euglycemia. When hyperglycemia was created, whole body NIMGU increased from 128 +/- 6 to 213 +/- 18 mg/min (P less than 0.01); NIMGU into non-skeletal muscle tissues was 134 +/- 11 and 111 +/- 6 mg/min at hyperglycemia and euglycemia, respectively, P = NS. Therefore, virtually all the hyperglycemia induced increment in NIMGU occurred in skeletal muscle. During hyperinsulinemia, IMGU in skeletal muscle represented 75 and 95% of body Rd, at euglycemia and hyperglycemia, respectively.

  11. Human platelet 5-hydroxytryptamine receptors: binding of [3H]-lysergic acid diethylamide (LSD). Effects of chronic neuroleptic and antidepressant drug administration.

    PubMed

    Grahame-Smith, D G; Geaney, D P; Schachter, M; Elliott, J M

    1988-02-15

    Chronic treatment with phenothiazines and thioxanthenes has been found to enhance 5-HT-induced aggregation of human platelets. A method has been developed to study 5-HT2 receptor binding sites on platelets utilising [3H]-LSD and more recently 125I/LSD. Results are presented which suggest that the LSD binding site is indeed the 5-HT2 binding site and that the LSD binding characterises the specific receptor responsible for 5-HT-induced shape change and aggregation. In a group of patients receiving phenothiazines or thioxanthenes, the Bmax of LSD binding was increased. The mean binding affinity was decreased possibly due to a persistence of neuroleptic in the platelet membrane preparation. Analysis showed that this was not the reason why the mean binding capacity was increased. The results show that chronic phenothiazine and thioxanthene delta treatment 'up-regulates' platelet 5-HT2 binding sites and that this may be accompanied by increased sensitivity to platelet aggregation by 5-HT. In normal subjects desipramine treatment increased the Bmax of platelet LSD binding and this was accompanied by an increased prolactin response to tryptophan which is thought to be mediated by central 5-HT function.

  12. Uptake of nitroaromatic compounds in plants : Implications for risk assessment of ammunition sites.

    PubMed

    Schneider, K; Oltmanns, J; Radenberg, T; Schneider, T; Pauly-Mundegar, D

    1996-09-01

    The uptake of nitroaromatic compounds by plants from the soil was studied at an ammunition site. After the development of analytical methods for 2,4,6-trinitrotoluene, aminodinitrotoluenes and dinitrotoluenes in plant material, we could show that these substances accumulated in the roots of plants and are found to a lesser extent inleaves and stems. We observed only moderate differences between various plant species. It is likely that a metabolic transformation in plants leads to the formation of dinitrotoluenes which are considered to be potent carcinogens. Results from soils with a wide range of explosive concentrations show a good correlation between the plant and soil concentrations. The relative accumulation in plant material is higher at lower soil concentrations. At low soil concentrations of about 1 mg trinitrotoluene/kg soil, an accumulation factor of about 0.5 can be derived. These data are an important input for the risk assessment of ammunition sites.

  13. Addition of the Neurokinin-1-Receptor Antagonist (RA) Aprepitant to a 5-Hydroxytryptamine-RA and Dexamethasone in the Prophylaxis of Nausea and Vomiting Due to Radiation Therapy With Concomitant Cisplatin

    SciTech Connect

    Jahn, Franziska; Jahn, Patrick; Sieker, Frank; Vordermark, Dirk; Jordan, Karin

    2015-08-01

    Purpose: To assess, in a prospective, observational study, the safety and efficacy of the addition of the neurokinin-1-receptor antagonist (NK1-RA) aprepitant to concomitant radiochemotherapy, for the prophylaxis of radiation therapy–induced nausea and vomiting. Patients and Methods: This prospective observational study compared the antiemetic efficacy of an NK1-RA (aprepitant), a 5-hydroxytryptamine-RA, and dexamethasone (aprepitant regimen) versus a 5-hydroxytryptamine-RA and dexamethasone (control regimen) in patients receiving concomitant radiochemotherapy with cisplatin at the Department of Radiation Oncology, University Hospital Halle (Saale), Germany. The primary endpoint was complete response in the overall phase, defined as no vomiting and no use of rescue therapy in this period. Results: Fifty-nine patients treated with concomitant radiochemotherapy with cisplatin were included in this study. Thirty-one patients received the aprepitant regimen and 29 the control regimen. The overall complete response rates for cycles 1 and 2 were 75.9% and 64.5% for the aprepitant group and 60.7% and 54.2% for the control group, respectively. Although a 15.2% absolute difference was reached in cycle 1, a statistical significance was not detected (P=.22). Furthermore maximum nausea was 1.58 ± 1.91 in the control group and 0.73 ± 1.79 in the aprepitant group (P=.084); for the head-and-neck subset, 2.23 ± 2.13 in the control group and 0.64 ± 1.77 in the aprepitant group, respectively (P=.03). Conclusion: This is the first study of an NK1-RA–containing antiemetic prophylaxis regimen in patients receiving concomitant radiochemotherapy. Although the primary endpoint was not obtained, the absolute difference of 10% in efficacy was reached, which is defined as clinically meaningful for patients by international guidelines groups. Randomized phase 3 studies are necessary to further define the potential role of an NK1-RA in this setting.

  14. Differential visualization of dopamine and norepinephrine uptake sites in rat brain using (/sup 3/H)mazindol autoradiography

    SciTech Connect

    Javitch, J.A.; Strittmatter, S.M.; Snyder, S.H.

    1985-06-01

    Mazindol is a potent inhibitor of neuronal dopamine (DA) and norepinephrine (NE) uptake. DA and NE uptake sites in rat brain have been differentially visualized using (/sup 3/H)mazindol autoradiography. At appropriate concentrations, desipramine (DMI) selectively inhibits (/sup 3/H)mazindol binding to NE uptake sites without significantly affecting binding to DA uptake sites. The localization of DMI-insensitive specific (/sup 3/H) mazindol binding, reflecting DA uptake sites, is densest in the caudate-putamen, the nucleus accumbens, the olfactory tubercle, the subthalamic nucleus, the ventral tegmental area, the substantia nigra (SN) pars compacta, and the anterior olfactory nuclei. In contrast, the localization of DMI-sensitive specific (/sup 3/H)mazindol binding, representing NE uptake sites, is densest in the locus coeruleus, the nucleus of the solitary tract, the bed nucleus of the stria terminalis, the paraventricular and periventricular nuclei of the hypothalamus, and the anteroventral thalamus. The distribution of DMI-insensitive specific (/sup 3/H)mazindol binding closely parallels that of dopaminergic terminal and somatodendritic regions, while the distribution of DMI-sensitive specific (/sup 3/H)mazindol binding correlates well with the regional localization of noradrenergic terminals and cell bodies. Injection of 6-hydroxydopamine, ibotenic acid, or colchicine into the SN decreases (/sup 3/H)mazindol binding to DA uptake sites in the ipsilateral caudate-putamen by 85%. In contrast, ibotenic acid lesions of the caudate-putamen do not reduce (/sup 3/H)mazindol binding to either the ipsilateral or contralateral caudate-putamen.

  15. 5-Hydroxytryptamine (5HT, serotonin)-1A receptor in brain areas of alcohol-preferring P and non-preferring NP rats

    SciTech Connect

    Reid, L.R.; Wong, D.T.; Li, T.K.; Lumeng, L. Indiana Univ., Indianapolis )

    1991-03-11

    Binding of {sup 3}H-80HDPAT to 5HT-1A receptor in membranes isolated from cerebral cortex of P and NP rats which had not been exposed to ethanol were equally sensitive to the displacement by nanomolar concentrations of agonists, including 5HT, buspirone and ipsapirone, and of antagonists metergoline and spiperone. Binding with increasing concentrations of {sup 3}H-80HDPAT was saturable in membranes of cerebral cortex from P and NP rats. Scatchard analysis revealed single components of binding sites with dissociation constants of 1.54 and 2.03 nM and maximum density of 177.3 and 129.3 fmol/mg protein, respectively, suggesting higher affinity and density of 5HT-1A receptors in cerebral cortex of P than NP rats. Higher densities are also found in other brain areas, including hypothalamus, striatum and hippocampus, of P than NP rats, but not in brainstem. Thus, an enrichment of 5HT-1A receptors in specific brain areas was developed during selective breeding for alcohol preference, or an upregulation of the receptors resulted from the lower concentrations of 5HT in brain areas of P as compared with NP rats.

  16. Adding 5-hydroxytryptamine receptor type 3 antagonists may reduce drug-induced nausea in poor insight obsessive-compulsive patients taking off-label doses of selective serotonin reuptake inhibitors: a 52-week follow-up case report

    PubMed Central

    2010-01-01

    Poor-insight obsessive-compulsive disorder (PI-OCD) is a severe form of OCD where the 'typically obsessive' features of intrusive, 'egodystonic' feelings and thoughts are absent. PI-OCD is difficult to treat, often requiring very high doses of serotonergic drugs as well as antipsychotic augmentation. When this occurs, unpleasant side effects as nausea are common, eventually further reducing compliance to medication and increasing the need for pharmacological alternatives. We present the case of a PI-OCD patient who developed severe nausea after response to off-label doses of the selective serotonin reuptake inhibitor (SSRI), fluoxetine. Drug choices are discussed, providing pharmacodynamic rationales and hypotheses along with reports of rating scale scores, administered within a follow-up period of 52 weeks. A slight reduction of fluoxetine dose, augmentation with mirtazapine and a switch from amisulpride to olanzapine led to resolution of nausea while preserving the anti-OCD therapeutic effect. Mirtazapine and olanzapine have already been suggested for OCD treatment, although a lack of evidence exists about their role in the course of PI-OCD. Both mirtazapine and olanzapine also act as 5-hydroxytryptamine receptor type 3 (5-HT3) blockers, making them preferred choices especially in cases of drug-induced nausea. PMID:21143969

  17. Mutations of L293 in transmembrane two of the mouse 5-hydroxytryptamine3A receptor alter gating and alcohol modulatory actions.

    PubMed

    Hu, Xiang-Qun; Hayrapetyan, Volodya; Gadhiya, Jay J; Rhubottom, Heather E; Lovinger, David M; Machu, Tina K

    2006-05-01

    1 The goal of this study was to determine whether mutations of L293 at the 15' position of TM2 in the 5-HT(3A) receptor alter macroscopic current kinetics, and if these changes could account for alterations in alcohol modulation. Receptor function was assessed in Xenopus oocytes under voltage-clamp and in HEK293 cells with whole-cell patch-clamp recording and rapid drug application. 2 Examination of responses of L293C and L293S receptors to agonist alone revealed enhanced activation, deactivation, and desensitization rates relative to the wild-type receptor. The L293G mutation produced marked slowing of deactivation and desensitization rates. Increased potency of 5-HT and increased efficacy of the partial agonist, DA, was also observed in these mutant receptors. 3 Ethanol and trichloroethanol (TCEt) enhancement of receptor function was reduced or eliminated in receptors containing L293 mutations to C, G, or S. The L293I mutant receptor retained ethanol and TCEt sensitivity. Ethanol and TCEt enhanced activation rate in the wild-type, but not the L293G and L293S receptors. No relationship was observed between any physicochemical property of the substituted amino acids and the change in alcohol potentiation of function. 4 The changes in receptor-channel properties in the mutant receptors support the idea that the L293 residue has important roles in channel gating. Our findings indicate that loss of allosteric modulation by alcohols is not related in any simple way to changes in channel kinetic properties brought about by L293 mutants. We did not observe any evidence that L293 is part of an alcohol binding site. PMID:16520747

  18. Effects of repeated oral doses of dexnorfenfluramine on 5-HT levels and 5-HT uptake sites in rat brain.

    PubMed

    Gobbi, M; Bergami, A; Caltavuturo, C; Valle, F D; Mennini, T; Caccia, S

    1996-11-15

    The effects of oral dexnorfenfluramine (DNF; 1-4 mg/kg, twice daily for 4 days), the active metabolite of dexfenfluramine, were examined on rat regional brain indole contents and [3H]citalopram binding. Two hours after the last dose, serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) were dose-dependently lowered at doses above 1.5 mg/kg, with slight regional differences. Cortical 5-HT uptake sites were reduced only at the highest dose. Above 2 mg/kg DNF also caused a more lasting reduction (4 weeks) of regional indoles and cortical 5-HT uptake sites. At this longer time while the decrease in hippocampal 5-HT levels and cortical 5-HT uptake sites remained essentially constant, cortical and striatal 5-HT levels were lowered less than at 2 h, suggesting a return toward control values.

  19. Water uptake by two river red gum ( Eucalyptus camaldulensis) clones in a discharge site plantation in the Western Australian wheatbelt

    NASA Astrophysics Data System (ADS)

    Marshall, John K.; Morgan, Anne L.; Akilan, Kandia; Farrell, Richard C. C.; Bell, David T.

    1997-12-01

    The heat-pulse technique was used to estimate year-long water uptake in a discharge zone plantation of 9-year-old clonal Eucalyptus camaldulensis Dehnh. near Wubin, Western Australia. Water uptake matched rainfall closely during weter months but exceeded rainfall as the dry season progressed. Average annual water uptake (1148 mm) exceeded rainfall (432 mm) by about 2.7 fold and approached 56% of pan evaporation for the area. The data suggest that at least 37% (i.e. ( {1}/{2.7}) × 100 ) of the lower catchment discharge zone should be planted to prevent the rise of groundwater. Water uptake varied with soil environment, season and genotype. Upslope trees used more water than did downslope trees. Water uptake was higher in E. camaldulensis clone M80 than in clone M66 until late spring. The difference reversed as summer progressed. Both clones, however, have the potential to dry out the landscape when potential evapotranspiration exceeds rainfall. This variation in water uptake within the species indicates the potential for manipulating plantation uptake by matching tree characteristics to site characteristics. Controlled experiments on the heat-pulse technique indicated accuracy errors of approximately 10%. This, combined with the ability to obtain long-term, continuous data and the superior logistics of use of the heat-pulse technique, suggests that results obtained by it would be much more reliable than those achieved by the ventilated chamber technique.

  20. Sites of calcium uptake of fish otoliths correspond with macular regions rich of carbonic anhydrase

    NASA Astrophysics Data System (ADS)

    Beier, M.; Anken, R.; Hilbig, R.

    2006-01-01

    Based on pharmacological data, it has been suggested that the enzyme carbonic anhydrase (CAH) plays a prominent role in the mineralization of fish otoliths. To directly test this proposal, the topographical distribution of CAH was histochemically analyzed in the utricular and saccular maculae of larval cichlid fish Oreochromis mossambicus. Further investigations were focussed on the sites of otolithic calcium uptake using the fluorescent calcium tracer alizarin-complexone (AC). Both in the utricle and the saccule, CAH-reactivity was prominent in regions on both sides of the sensory macula (centrifugal (cf) and centripetal (cp) areas), which reportedly contain ionocytes, specialized cells regulating the ionic composition of the endolymph. (The terms centrifugal and centripetal were chosen instead of lateral and medial, because the saccule is positioned perpendicular to the utricle; “lateral” and “medial” thus do not allow an unambiguous allocation of the respective regions.) In the saccule, the size of cf and cp did not differ from each other, whereas, in the utricle, cp was considerably larger as compared to cf (CAH-reactivity per μm2 was nearly identical in both areas of both endorgans). AC-incubation resulted in a fluorescent band on the proximal surface of the otoliths (this surface lies next to the sensory epithelium). In saccular otoliths (sagittae), the area of the band did not differ between centrifugal and centripetal otolith regions, whereas in the utricular otoliths (lapilli), the area of the centripetal AC-band was larger in size as compared to the centrifugal one (AC-fluorescence per μm2 did not differ between the areas analyzed in both types of otoliths). These results strongly suggest that calcium/carbonate uptake of otoliths takes place especially in those regions of their proximal face which are located adjacent to CAH-rich areas of the macular epithelium. It is thus concluded that CAH is directly involved in otolith calcification. The

  1. Role of 5-Hydroxytryptamine 1A Receptors in 6-Hydroxydopmaine-induced Catalepsy-like Immobilization in Rats: a Therapeutic Approach for Treating Catalepsy of Parkinson’s Disease

    PubMed Central

    eyhani-rad, Siamak; Mohajjel Nayebi, Alireza; Mahmoudi, Javad; Samini, Morteza; Babapour, Vahab

    2012-01-01

    We have shown that buspirone, a partial agonist of 5-hydroxytryptamine 1A (5-HT1A) receptors, improves motor dysfunctions induced by 6-hydroxydopamine (6-OHDA) and haloperidol in rats. The present work extends these findings by investigating the role of 5-HT1A receptors on catalepsy-like immobilization in rats, a model of Parkinson’s disease. Catalepsy was induced by unilateral infusion of 6-OH-dopamine (8 μg/2μL/rat) into the central region of the substantia nigra, compact part (SNc) and assayed by bar-test method 5, 60, 120 and 180 min after the drugs administration. The involvement of 5-HT1A receptors in 6-OHDA-induced catalepsy was studied through intraperitoneal (0.25, 0.5 and 1mg/Kg IP) and intrasubstantia nigra, compact part (10 μg/rat, intra-SNc) injection of 8-hydroxy-2-[di-n-propylamino] tetralin (8-OHDPAT) as well as administration of 1-(2-methoxyphenyl)-4-[4-(2-pthalimmido) butyl] piperazine hydrobromide (0.1, 0.5 and 1 mg/Kg, NAN-190, IP). NAN-190 (1 mg/Kg, IP) and 8-OHDPAT (1 mg/Kg, IP and 10 μg/rat, intra-SNc) increased and decreased 6-OHDA-induced catalepsy respectively. In normal (non 6-OHDA-lesioned) rats, NAN-190 (1 mg/Kg, IP) increased the elapsed time in bar-test while 8-OHDPAT did not produce any significant effect. The anticataleptic effect of 8-OHDPAT (1 mg/Kg, IP) was reversed markedly by co-injection with NAN-190 (1 mg/Kg, IP). These findings suggest that 5-HT1A receptors are involved in 6-OHDA-induced catalepsy-like immobilization. PMID:24250551

  2. Effects of high-dose fenfluramine treatment on monoamine uptake sites in rat brain: Assessment using quantitative autoradiography

    SciTech Connect

    Appel, N.M.; Mitchell, W.M.; Contrera, J.F.; De Souza, E.B. )

    1990-01-01

    Fenfluramine is an amphetamine derivative that in humans is used primarily as an anorectic agent in the treatment of obesity. In rats, subchronic high-dose d,l-fenfluramine treatment (24 mg/kg subcutaneously, twice daily for 4 days) causes long-lasting decreases in brain serotonin (5HT), its metabolite 5-hydroxyindoleacetic acid, and high-affinity 5HT uptake sites. Moreover, this high-dose treatment regimen causes both selective long-lasting decreases in fine-caliber 5HT-immunoreactive axons and appearance of other 5HT-immunoreactive axons with morphology characteristic of degenerating axons. Determination of the potential neurotoxic effects of fenfluramine treatment using immunohistochemistry is limited from the perspectives that staining is difficult to quantify and that it relies on presence of the antigen (in this case 5HT), and the 5HT-depleting effects of fenfluramine are well known. In the present study, we used quantitative in vitro autoradiography to assess, in detail, the density and regional distribution of (3H)paroxetine-labeled 5HT and (3H)mazindol-labeled catecholamine uptake sites in response to the high-dose fenfluramine treatment described above. Because monoamine uptake sites are concentrated on monoamine-containing nerve terminals, decreases in uptake site density would provide a quantitative assessment of potential neurotoxicity resulting from this fenfluramine treatment regimen. Marked decreases in densities of (3H)paroxetine-labeled 5HT uptake sites occurred in brain regions in which fenfluramine treatment decreased the density of 5HT-like immunostaining when compared to saline-treated control rats. These included cerebral cortex, caudate putamen, hippocampus, thalamus, and medial hypothalamus.

  3. Soil contamination and plant uptake of heavy metals at polluted sites in China.

    PubMed

    Wang, Qing-Ren; Cui, Yan-Shan; Liu, Xiu-Mei; Dong, Yi-Ting; Christie, Peter

    2003-05-01

    We investigated heavy metal contamination in soils and plants at polluted sites in China including some with heavy industries, metal mining, smelting and untreated wastewater irrigation areas. We report our main findings in this paper. The concentrations of heavy metals, including Cd and Zn, in the soils at the investigated sites were above the background levels, and generally exceeded the Government guidelines for metals in soil. The concentrations of metals in plants served to indicate the metal contamination status of the site, and also revealed the abilities of various plant species to take up and accumulate the metals from the soil. Substantial differences in the accumulation of heavy metals were observed among the plant species investigated. Polygonum hydropiper growing on contaminated soils in a sewage pond had accumulated 1061 mg kg(-1) of Zn in its shoots. Rumex acetosa L. growing near a smelter had accumulated more than 900 mg kg(-1) of Zn both in its shoots and roots. Therefore these species have potential for phytoremediation of metal-contaminated sites. Our results indicate the need to elucidate the dynamics of soil metal contamination of plants and the onward movement of metal contaminants into the food chain. Also our results indicate that the consumption of rice grown in paddy soils contaminated with Cd, Cr or Zn may pose a serious risk to human health, because from 24 to 22% of the total metal content in the rice biomass was concentrated in the rice grain. Platanus acerifolia growing on heavily contaminated soil accumulated only very low levels of heavy metals, and this mechanism for excluding metal uptake may have value in crop improvement. Sources of metal entering the environmental matrices studied included untreated wastewater, tailings or slurries and dust depositions from metal ore mining, and sewage sludge. Pb, Zn or Cd concentrations declined with the distance from metal smelter in accordance with a good exponential correlation (R2

  4. Similarity of nutrient uptake and root dimensions of Engelmann spruce and subalpine fir at two contrasting sites in Colorado

    SciTech Connect

    Yanai, R; McFarlane, K; Lucash, M; Kulpa, S; Wood, D

    2009-10-09

    Nutrient uptake capacity is an important parameter in modeling nutrient uptake by plants. Researchers commonly assume that uptake capacity measured for a species can be used across sites. We tested this assumption by measuring the nutrient uptake capacity of intact roots of Engelmann spruce (Picea engelmanni Parry) and subalpine fir (Abies lasiocarpa (Hook.) Nutt.) at Loch Vale Watershed and Fraser Experimental Forest in the Rocky Mountains of central Colorado. Roots still attached to the tree were exposed to one of three concentrations of nutrient solutions for time periods ranging from 1 to 96 hours, and solutions were analyzed for ammonium, nitrate, calcium, magnesium, and potassium. Surprisingly, the two species were indistinguishable in nutrient uptake within site for all nutrients (P > 0.25), but uptake rates differed by site. In general, nutrient uptake was higher at Fraser (P = 0.01, 0.15, 0.03, 0.18 for NH{sub 4}{sup +}, NO{sub 3}{sup -}, Ca{sup 2+}, and K{sup +}, respectively), which is west of the Continental Divide and has lower atmospheric deposition of N than Loch Vale. Mean uptake rates by site for ambient solution concentrations were 0.12 {micro}mol NH{sub 4}{sup +} g{sub fwt}{sup -1} h{sup -1}, 0.02 {micro}mol NO{sub 3}{sup -} g{sub fwt}{sup -1}, 0.21 {micro}mol Ca{sup 2+} g{sub fwt}{sup -1} h{sup -1}, and 0.01 {micro}mol Mg{sup 2+} g{sub fwt}{sup -1} h{sup -1} at Loch Vale, and 0.21 {micro}mol NH{sub 4}{sup +} f{sub fwt}{sup -1}h{sup -1}, 0.04 {micro}mol NO{sub 3}{sup -} g{sub fwt}{sup -1} h{sup -1}, 0.51 {micro}mol Ca{sup 2+}g{sub fwt}{sup -1}h{sup -1}, and 0.07 {micro}mol Mg{sup 2+} f{sub fwt}{sup -1}h{sup -1} at Fraser. The importance of site conditions in determining uptake capacity should not be overlooked when parameterizing nutrient uptake models. We also characterized the root morphology of these two species and compared them to other tree species we have measured at various sites in the northeastern USA. Engelman spruce and subalpine fir

  5. Activation of mGlu2/3 metabotropic glutamate receptors negatively regulates the stimulation of inositol phospholipid hydrolysis mediated by 5-hydroxytryptamine2A serotonin receptors in the frontal cortex of living mice.

    PubMed

    Molinaro, G; Traficante, A; Riozzi, B; Di Menna, L; Curto, M; Pallottino, S; Nicoletti, F; Bruno, V; Battaglia, G

    2009-08-01

    The interaction between 5-hydroxytryptamine(2A) (5-HT(2A)) serotonin receptors and metabotropic glutamate (mGlu) 2/3 receptors underlies the antipsychotic activity of mGlu2/3 receptor agonists in experimental animals and humans. The molecular nature of this interaction is only partially known. We here report for the first time that pharmacological activation of mGlu2/3 receptors attenuates the stimulation of polyphosphoinositide (PI) hydrolysis mediated by 5-HT(2A) receptors in the frontal cortex of living mice. Mice were injected intracerebroventricularly with [myo-(3)H]inositol and treated with drugs 1 h after a pretreatment with lithium, which blocks the conversion of inositol monophosphate into free inositol. Systemic injection of the mGlu2/3 receptor agonist (-)-2-oxa-4-aminocyclo[3.1.0]hexane-4,6-dicarboxylic acid (LY379268) inhibited the stimulation of PI hydrolysis induced by the hallucinogenic 5-HT(2A) receptor agonist (+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) without affecting the stimulation by mGlu1/5 or muscarinic receptors. The action of LY379268 was prevented by the preferential mGlu2/3 receptor antagonist (2S,1'S,2'S)-2-(9-xanthylmethyl)-2-(2'-carboxycyclopropyl)glycine (LY341495). N-(4'-cyano-biphenyl-3-yl)-N-(3-pyridinylmethyl)-ethanesulfonamide hydrochloride (LY566332), a selective mGlu2 receptor enhancer, also reduced DOI-stimulated PI hydrolysis when combined with subthreshold doses of LY379268. Systemic LY379268 inhibited DOI-stimulated PI hydrolysis in mice lacking either mGlu2 or mGlu3 receptors but was inactive in double mGlu2/mGlu3 receptor knockout mice, suggesting that both mGlu2 and mGlu3 receptors interact with 5-HT(2A) receptors. Surprisingly, contrasting results were obtained in cortical slice preparations, where LY379268 amplified both DOI- and 3,5-dihydroxyphenylglycine-stimulated PI hydrolysis. Amplification was abrogated by the mGlu5 receptor antagonist 2-methyl-6-(phenylethynyl)pyridine, suggesting that

  6. Exemplifying whole-plant ozone uptake in adult forest trees of contrasting species and site conditions.

    PubMed

    Nunn, Angela J; Wieser, Gerhard; Metzger, Ursula; Löw, Markus; Wipfler, Philip; Häberle, Karl-Heinz; Matyssek, Rainer

    2007-04-01

    Whole-tree O3 uptake was exemplified for Picea abies, Fagus sylvatica and Larix decidua in stands at high and low altitude and contrasting water availability through sap flow measurement in tree trunks, intrinsically accounting for drought and boundary layer effects on O3 flux. O3 uptake of evergreen spruce per unit foliage area was enhanced by 100% at high relative to low elevation, whereas deciduous beech and larch showed similar uptake regardless of altitude. The responsiveness of the canopy conductance to water vapor and, as a consequence, O3 uptake to soil moisture and air humidity did not differ between species. Unifying findings at the whole-tree level will promote cause-effect based O3 risk assessment and modeling. PMID:16996178

  7. Exemplifying whole-plant ozone uptake in adult forest trees of contrasting species and site conditions.

    PubMed

    Nunn, Angela J; Wieser, Gerhard; Metzger, Ursula; Löw, Markus; Wipfler, Philip; Häberle, Karl-Heinz; Matyssek, Rainer

    2007-04-01

    Whole-tree O3 uptake was exemplified for Picea abies, Fagus sylvatica and Larix decidua in stands at high and low altitude and contrasting water availability through sap flow measurement in tree trunks, intrinsically accounting for drought and boundary layer effects on O3 flux. O3 uptake of evergreen spruce per unit foliage area was enhanced by 100% at high relative to low elevation, whereas deciduous beech and larch showed similar uptake regardless of altitude. The responsiveness of the canopy conductance to water vapor and, as a consequence, O3 uptake to soil moisture and air humidity did not differ between species. Unifying findings at the whole-tree level will promote cause-effect based O3 risk assessment and modeling.

  8. High and Reversible Ammonia Uptake in Mesoporous Azolate Metal-Organic Frameworks with Open Mn, Co, and Ni Sites.

    PubMed

    Rieth, Adam J; Tulchinsky, Yuri; Dincă, Mircea

    2016-08-01

    A series of new mesoporous metal-organic frameworks (MOFs) made from extended bisbenzenetriazolate linkers exhibit coordinatively unsaturated metal sites that are responsible for high and reversible uptake of ammonia. Isostructural Mn, Co, and Ni materials adsorb 15.47, 12.00, and 12.02 mmol of NH3/g, respectively, at STP. Importantly, these near-record capacities are reversible for at least three cycles. These results demonstrate that azolate MOFs are sufficiently thermally and chemically stable to find uses in recyclable sorption, storage, and potentially separation of chemically challenging and/or corrosive gases, especially when designed to exhibit a high density of open metal sites.

  9. [THE THYROID STATUS OF RATS IMMUNIZED WITH PEPTIDES DERIVED FROM THE EXTRACELLULAR REGIONS OF THE TYPES 3 AND 4 MELANOCORTIN RECEPTORS AND THE 1B-SUBTYPE 5-HYDROXYTRYPTAMINE RECEPTOR].

    PubMed

    Derkach, K V; Moyseuk, I V; Shpakova, E A; Sphakov, A O

    2015-01-01

    The activity of the hypothalamic-pituitary-thyroid (HPT) axis is controlled by the brain neurotransmitter systems, including the melanocortin signaling system. Pharmacological inhibition of type 4 melanocortin receptor (M4R) leads to disruption of the functioning of HPT axis and to reduction of the level of thyroid hormones. At the same time, the data on how prolonged inhibition of M4R affects this axis and on its role in regulation of M3R are absent. The relationship between the thyroid status and the activity of 1B-subtype 5-hydroxytryptamine receptor (5-HT1BR) is scarcely explored. The aim of this work to study the effects of chronic inhibition of M3R, M4R and 5-HT1BR induced by immunization of rats with BSA-conjugated peptide derived from the extracellular regions of these receptors on the thyroid status and the activity of thyroid stimulating hormone (TSH)-sensitive adenylyl cyclase signaling system (ACSS) in the thyroid glarid (TG) of the immunized animals. In rats immunized with the peptides K-[TSLHL WNRSSHGLHG11-25]-A of M4R, A[PTNPYCICTTAH269-280]-A of M3R and. [QAKAEE-EVSEC(Acm)-VVNTDH189-205]-A of 5-HT1BR levels of thyroid hormones such as fT4, tT4 and tT3 were significantly reduced. In rats immunized with M4R and M3R peptides, an increase of TSH was detected whereas in the animals immunized with 5-HT1BR peptide the level of TSH, on the contrary, was reduced. In the TG of rats immunized with M4R and M3R peptides, the stimulatory effects of hormones (TSH, PA-CAP-3 8) and GppNHp on adenylyl cyclase activity were attenuated, and the changes were most pronounced in the case M4R peptide immunization. After immunization with 5-HT1BR peptide the stimulatory effects of TSH, PACAP-38 and GppNHp were retained. Thus, the main cause of thyroid hormones deficit in rats immunized with M4R and M3R peptides was the decreased sensitivity of ACSS thyrocytes to TSH, whereas in rats iimunized with 5-HT1BR peptide the deficit of thyroid hormones was associated with decreased

  10. Different components of /sup 3/H-imipramine binding in rat brain membranes: relation to serotonin uptake sites

    SciTech Connect

    Gobbi, M.; Taddei, C.; Mennini, T.

    1988-01-01

    In the present paper, the authors confirm and extend previous studies showing heterogeneous /sup 3/H-imipramine (/sup 3/H-IMI) binding sites. Inhibition curves of various drugs (serotonin, imipramine, desmethyl-imipramine, d-fenfluramine, d-norfenfluramine and indalpine, a potent serotonin uptake inhibitor) obtained using 2 nM /sup 3/H-IMI and in presence of 120 mM NaCl, confirmed the presence of at least three /sup 3/H-IMI binding sites: two of these were serotonin-insensitive while the third one was selectively inhibited by serotonin and indalpine with nanomolar affinities. Moreover this last component was found to be selectively modulated by chronic imipramine treatment thus suggesting a close relation to serontonin uptake mechanism. These data indicate that the use of a more selective inhibitors of the serotonin-sensitive component (like indalpine or serotonin itself) to define non specific /sup 3/H-IMI, may be of help in understanding its relation with serotonin uptake system. 22 references, 2 figures, 2 tables.

  11. Knowledge, attitude, and uptake related to human papillomavirus vaccination among young women in Germany recruited via a social media site

    PubMed Central

    Remschmidt, Cornelius; Walter, Dietmar; Schmich, Patrick; Wetzstein, Matthias; Deleré, Yvonne; Wichmann, Ole

    2014-01-01

    Background: Many industrialized countries have introduced human papillomavirus (HPV) vaccination of young women, but vaccine uptake often remains suboptimal. This study aimed to investigate whether a social media site like Facebook is an appropriate tool to assess knowledge, attitude and uptake related to HPV vaccination in young women in Germany. Methods: Between December 2012 and January 2013 two different targeting strategies were implemented on Facebook, providing a link to an online questionnaire. Advertisements were displayed to female Facebook users aged 18–25 years living in Germany. During the simple targeting strategy, advertisements comprised health-related images along with various short titles and text messages. During the focused strategy, advertisements were targeted to users who in addition had certain fashion brands or pop stars listed on their profiles. The targeting strategies were compared with respect to participant characteristics. Univariate and multivariate analyses were used to identify factors associated with HPV vaccine uptake. Results: A total of 1161 women participated. The two targeting strategies resulted in significant differences regarding educational status and migrant background. Overall, awareness of HPV was high, but only 53% received at least one vaccine dose. In multivariate analysis, HPV vaccine uptake was independently associated with a physician's recommendation and trust in vaccine effectiveness. Concerns of adverse effects were negatively associated with vaccine uptake. Discussion: Social network recruitment permits fast and convenient access to young people. Sample characteristics can be manipulated by adjusting targeting strategies. There is further need for promoting knowledge of HPV vaccination among young women. Physicians have a major role in the vaccination decision-making process of young women. PMID:25483492

  12. Root water uptake model based on water potential gradient with water redistribution via roots: application to coniferous forest site

    NASA Astrophysics Data System (ADS)

    Votrubova, Jana; Vogel, Tomas; Dohnal, Michal; Dusek, Jaromir; Tesar, Miroslav

    2013-04-01

    A simple macroscopic vertically distributed plant root water uptake (RWU) model based on traditional water-potential-gradient formulation (Vogel et al., 2013), in which the uptake rates are directly proportional to the potential gradient and indirectly proportional to the local soil and root resistances to water flow, was tested. This RWU modeling approach was implemented in a one-dimensional dual-continuum model of soil water flow based on Richards' equation and used to simulate soil water distribution changes during a vegetation season at a forest site located in a temperate humid climate of central Europe. The main objectives were to test the ability of the presented RWU model to simulate the observed soil-plant-atmosphere interactions, and to examine the differences between empirical and more physically-based RWU modeling approaches (accommodated in the same soil water flow model). The tested RWU model was capable of simulating both the compensatory root water uptake, in situations when reduced uptake from dry layers was compensated for by increased uptake from wetter layers, and the root-mediated hydraulic redistribution of soil water, contributing to more natural soil moisture distribution throughout the root zone. Comparison of the model results with the sap flow observed reveals some limitations related to the quasi-steady-state assumption for the plant xylem and zero transpiration rates prescribed during nights and precipitation. This stated, the model seems to simulate adequately both the regular nightly hydraulic redistribution, due to reduced night transpiration, and the episodic daytime hydraulic redistribution during wet canopy events. The model results were compared to simulations produced using the semi-empirical RWU model of Feddes. Based on both an improved agreement between the observed and simulated soil water pressure responses to daily variations of transpiration, and a more realistic seasonal distribution of the transpiration rate reduction

  13. Plant selective uptake of halogenated flame retardants at an e-waste recycling site in southern China.

    PubMed

    Wang, Shaorui; Wang, Yan; Luo, Chunling; Li, Jun; Yin, Hua; Zhang, Gan

    2016-07-01

    The concentrations and homolog patterns of halogenated flame retardants (HFRs) in vegetables grown at an e-waste contaminated site were investigated. Polybrominated diphenyl ethers (PBDEs) were the dominant HFRs in vegetable tissues, with concentrations ranging from 10.3 to 164 ng g(-1) and 1.16-107 ng g(-1) in shoots and roots, respectively, followed by novel brominated flame retardants (NBFRs) and dechlorane plus (DPs). This is an indication that PBDE contamination in vegetables grown around e-waste recycling sites may pose a risk to the local terrestrial ecosystem and residents. In addition, this is the first report on the concentrations and compositions of NBFRs in vegetables around e-waste recycling sites. The HFRs concentrations in vegetables varied greatly with the vegetable species, with the highest concentrations observed in Brassica oleracea var. capitata. Root concentration factors (RCF) decreased with increasing log Kow of HFRs, which indicated that the uptake of HFRs was controlled mainly by log Kow. Dissimilar HFRs profiles in shoots and roots suggested that the uptake and translocation of HFRs by plants were selective, with lower halogenated congeners prone to accumulation in vegetable tissues. Positive relationships between PBDEs and their substitutes were observed in vegetable tissues, suggesting that the replacement of PBDEs by NBFRs has not resulted in an obvious transition in plants within the study area. PMID:27149147

  14. Plant selective uptake of halogenated flame retardants at an e-waste recycling site in southern China.

    PubMed

    Wang, Shaorui; Wang, Yan; Luo, Chunling; Li, Jun; Yin, Hua; Zhang, Gan

    2016-07-01

    The concentrations and homolog patterns of halogenated flame retardants (HFRs) in vegetables grown at an e-waste contaminated site were investigated. Polybrominated diphenyl ethers (PBDEs) were the dominant HFRs in vegetable tissues, with concentrations ranging from 10.3 to 164 ng g(-1) and 1.16-107 ng g(-1) in shoots and roots, respectively, followed by novel brominated flame retardants (NBFRs) and dechlorane plus (DPs). This is an indication that PBDE contamination in vegetables grown around e-waste recycling sites may pose a risk to the local terrestrial ecosystem and residents. In addition, this is the first report on the concentrations and compositions of NBFRs in vegetables around e-waste recycling sites. The HFRs concentrations in vegetables varied greatly with the vegetable species, with the highest concentrations observed in Brassica oleracea var. capitata. Root concentration factors (RCF) decreased with increasing log Kow of HFRs, which indicated that the uptake of HFRs was controlled mainly by log Kow. Dissimilar HFRs profiles in shoots and roots suggested that the uptake and translocation of HFRs by plants were selective, with lower halogenated congeners prone to accumulation in vegetable tissues. Positive relationships between PBDEs and their substitutes were observed in vegetable tissues, suggesting that the replacement of PBDEs by NBFRs has not resulted in an obvious transition in plants within the study area.

  15. Cellular sites of estrogen and antiestrogen uptake, retention and action: comparative autoradiographic studies in the immature rat uterus

    SciTech Connect

    Ennis, B.W.

    1987-01-01

    This purpose of this study is to clarify the mechanism of action of antiestrogens: agents used for treating breast cancer and as probes for studying the mechanisms of action of estrogen. Nuclear uptake and retention of estrogen and antiestrogen were determined in the different cell types of the immature rat uterus, by quantitative autoradiography, after an injection of tritiated hydroxytamoxifen ((/sup 3/H)TAM(OH)) or tritiated estradiol ((/sup 3/H)E/sub 2/). The effect of TAM(OH) and E/sub 2/ on progesterone receptor content was assessed in the different cell types by determining nuclear uptake of the synthetic progestin (/sup 3/H)Org 2058. The results indicate that antiestrogen and estrogen localize to nuclei of the same uterine cell types, but that this nuclear uptake differs among the uterine tissue compartments, that antiestrogen is taken up considerably slower and retained longer than estrogen and that antiestrogen and estrogen differentially affect progesterone receptor content in the different cell types. The results further suggest that antiestrogen-specific binding sites exist in the cytoplasm of uterine luminal epithelium.

  16. Site-Specific Radioiodination of HER2-Targeting Affibody Molecules using 4-Iodophenethylmaleimide Decreases Renal Uptake of Radioactivity

    PubMed Central

    Strand, Joanna; Nordeman, Patrik; Honarvar, Hadis; Altai, Mohamed; Orlova, Anna; Larhed, Mats; Tolmachev, Vladimir

    2015-01-01

    Affibody molecules are small scaffold-based affinity proteins with promising properties as probes for radionuclide-based molecular imaging. However, a high reabsorption of radiolabeled Affibody molecules in kidneys is an issue. We have shown that the use of 125I-3-iodo-((4-hydroxyphenyl)ethyl)maleimide (IHPEM) for site-specific labeling of cysteine-containing Affibody molecules provides high tumor uptake but low radioactivity retention in kidneys. We hypothesized that the use of 4-iodophenethylmaleimide (IPEM) would further reduce renal retention of radioactivity because of higher lipophilicity of radiometabolites. An anti-human epidermal growth factor receptor type 2 (HER2) Affibody molecule (ZHER2:2395) was labeled using 125I-IPEM with an overall yield of 45±3 %. 125I-IPEM-ZHER2:2395 bound specifically to HER2-expressing human ovarian carcinoma cells (SKOV-3 cell line). In NMRI mice, the renal uptake of 125I-IPEM-ZHER2:2395 (24±2 and 5.7±0.3 % IA g−1at 1 and 4 h after injection, respectively) was significantly lower than uptake of 125I-IHPEM-ZHER2:2395 (50±8 and 12±2 % IA g−1at 1 and 4 h after injection, respectively). In conclusion, the use of a more lipophilic linker for the radioiodination of Affibody molecules reduces renal radioactivity. PMID:25969816

  17. Selective labeling of serotonin uptake sites in rat brain by (/sup 3/H)citalopram contrasted to labeling of multiple sites by (/sup 3/H)imipramine

    SciTech Connect

    D'Amato, R.J.; Largent, B.L.; Snowman, A.M.; Snyder, S.H.

    1987-07-01

    Citalopram is a potent and selective inhibitor of neuronal serotonin uptake. In rat brain membranes (/sup 3/H)citalopram demonstrates saturable and reversible binding with a KD of 0.8 nM and a maximal number of binding sites (Bmax) of 570 fmol/mg of protein. The drug specificity for (/sup 3/H)citalopram binding and synaptosomal serotonin uptake are closely correlated. Inhibition of (/sup 3/H)citalopram binding by both serotonin and imipramine is consistent with a competitive interaction in both equilibrium and kinetic analyses. The autoradiographic pattern of (/sup 3/H)citalopram binding sites closely resembles the distribution of serotonin. By contrast, detailed equilibrium-saturation analysis of (/sup 3/H)imipramine binding reveals two binding components, i.e., high affinity (KD = 9 nM, Bmax = 420 fmol/mg of protein) and low affinity (KD = 553 nM, Bmax = 8560 fmol/mg of protein) sites. Specific (/sup 3/H)imipramine binding, defined as the binding inhibited by 100 microM desipramine, is displaced only partially by serotonin. Various studies reveal that the serotonin-sensitive portion of binding corresponds to the high affinity sites of (/sup 3/H)imipramine binding whereas the serotonin-insensitive binding corresponds to the low affinity sites. Lesioning of serotonin neurons with p-chloroamphetamine causes a large decrease in (/sup 3/H)citalopram and serotonin-sensitive (/sup 3/H)imipramine binding with only a small effect on serotonin-insensitive (/sup 3/H)imipramine binding. The dissociation rate of (/sup 3/H)imipramine or (/sup 3/H)citalopram is not altered by citalopram, imipramine or serotonin up to concentrations of 10 microM. The regional distribution of serotonin sensitive (/sup 3/H)imipramine high affinity binding sites closely resembles that of (/sup 3/H)citalopram binding.

  18. Uptake of gamma-aminobutyric acid and L-glutamic acid by synaptosomes from postmortem human cerebral cortex: multiple sites, sodium dependence and effect of tissue preparation.

    PubMed

    Dodd, P R; Watson, W E; Morrison, M M; Johnston, G A; Bird, E D; Cowburn, R F; Hardy, J A

    1989-06-26

    The uptake of gamma-aminobutyric acid (GABA) and L-glutamic acid by synaptosomes prepared from frozen postmortem human brain was shown to be effected via distinct high and low affinity sites. At approximately 17 h postmortem delay, the kinetic parameters for GABA uptake were: high affinity site, Km 7.1 +/- 2.5 microM, Vmax 18.7 +/- 4.8 nmol.min-1 per 100 mg protein; low affinity site, Km 2 +/- 1 mM, Vmax 425 +/- 250 nmol.min-1 per 100 mg protein (means +/- S.E.M., n = 13). Kinetic parameters for L-glutamate uptake were: high affinity site, Km 7.5 +/- 1.0 microM, Vmax 85 +/- 8 nmol.min-1 per 100 mg protein; low affinity site, Km 1.8 +/- 1.2 mM. Vmax 780 +/- 175 nmol.min-1 per 100 mg protein (n = 11). A detailed kinetic analysis of high affinity GABA uptake was performed over a range of sodium ion concentrations. The results were consistent with a coupling ratio of one Na+ ion to one GABA molecule; a similar result was found with rat brain synaptosomes. However, rat and human synaptosomes differed in the degree to which the substrate affinity of the high affinity GABA uptake site varied with decreasing Na+ ion concentration. High affinity GABA uptake was markedly affected by the method used to freeze and divide the tissue, but did not vary greatly in different cortical regions. There was some decline of high affinity GABA uptake activity with postmortem delay, apparently due to a loss of sites rather than a change in site affinity.

  19. A comparison of 90Sr and 137Cs uptake in plants via three pathways at two Chernobyl-contaminated sites.

    PubMed

    Malek, M A; Hinton, T G; Webb, S B

    2002-01-01

    Foliar absorption of resuspended 90Sr, root uptake and contamination adhering to leaf surfaces (i.e. soil loading) were compared at two Chernobyl-contaminated sites, Chistogalovka and Polesskoye. Although foliar absorption of resuspended 90Sr was quantifiable, its contribution amounted to less than 10% of the plants' total, above-ground contamination. Root uptake was 200 times greater than foliar absorption at the near-field site of Chistogalovka and eight times greater at Polesskoye, where the fallout consisted of the more soluble condensation-type, rather than fuel particles. Strontium's bioavailability exceeded that of 137Cs (analyzed in the same plants) by orders of magnitude when compared using concentration ratios. Simplistic, cumulative effective dose calculations for humans ingesting 90Sr- and 137Cs-contaminated plants revealed that the dose at Chistogalovka was greater from 90Sr (185 mSv vs. 3 mSv from 137Cs), while at Polesskoye the dose from 137Cs (66 mSv) was 30 times greater than from 90Sr (2 mSv). PMID:11814162

  20. The cell pole: the site of cross talk between the DNA uptake and genetic recombination machinery.

    PubMed

    Kidane, Dawit; Ayora, Silvia; Sweasy, Joann B; Graumann, Peter L; Alonso, Juan C

    2012-01-01

    Natural transformation is a programmed mechanism characterized by binding of free double-stranded (ds) DNA from the environment to the cell pole in rod-shaped bacteria. In Bacillus subtilis some competence proteins, which process the dsDNA and translocate single-stranded (ss) DNA into the cytosol, recruit a set of recombination proteins mainly to one of the cell poles. A subset of single-stranded binding proteins, working as "guardians", protects ssDNA from degradation and limit the RecA recombinase loading. Then, the "mediators" overcome the inhibitory role of guardians, and recruit RecA onto ssDNA. A RecA·ssDNA filament searches for homology on the chromosome and, in a process that is controlled by "modulators", catalyzes strand invasion with the generation of a displacement loop (D-loop). A D-loop resolvase or "resolver" cleaves this intermediate, limited DNA replication restores missing information and a DNA ligase seals the DNA ends. However, if any step fails, the "rescuers" will repair the broken end to rescue chromosomal transformation. If the ssDNA does not share homology with resident DNA, but it contains information for autonomous replication, guardian and mediator proteins catalyze plasmid establishment after inhibition of RecA. DNA replication and ligation reconstitute the molecule (plasmid transformation). In this review, the interacting network that leads to a cross talk between proteins of the uptake and genetic recombination machinery will be placed into prospective.

  1. Beta-test Results for an HPV Information Web site: GoHealthyGirls.org – Increasing HPV Vaccine Uptake in the United States

    PubMed Central

    Nodulman, Jessica A.; Kong, Alberta S.; Wheeler, Cosette M.; Buller, David B.; Woodall, W. Gill

    2014-01-01

    A web site, GoHealthyGirls, was developed to educate and inform parents and their adolescent daughters about human papillomavirus (HPV) and HPV vaccines. This article provides an overview of web site development and content followed by the results of a beta-test of the web site. 63 New Mexican parents of adolescent girls tested the site. Results indicated that GoHealthyGirls was a functioning and appealing web site. During this brief educational intervention, findings suggest that the web site has the potential to increase HPV vaccine uptake. This research supports the Internet as a valuable channel to disseminate health education and information to diverse populations. PMID:25221442

  2. The cell pole: The site of cross talk between the DNA uptake and genetic recombination machinery

    PubMed Central

    Kidane, Dawit; Ayora, Silvia; Sweasy, Joann; Graumann, Peter L.; Alonso, Juan C.

    2012-01-01

    Natural transformation is a programmed mechanism characterized by binding of free double-stranded (ds) DNA from the environment to the cell pole in rod-shaped bacteria. In Bacillus subtilis some competence proteins, which process the dsDNA and translocate single-stranded (ss) DNA into the cytosol, recruit a set of recombination proteins mainly to one of the cell poles. A subset of single-stranded binding proteins, working as “guardians”, protect ssDNA from degradation and limit the RecA recombinase loading. Then, the “mediators” overcome the inhibitory role of guardians, and recruit RecA onto ssDNA. A RecA·ssDNA filament searches for homology on the chromosome and, in a process that is controlled by “modulators”, catalyzes strand invasion with the generation of a displacement loop (D-loop). A D-loop resolvase or “resolver” cleaves this intermediate, limited DNA replication restores missing information and a DNA ligase seals the DNA ends. However, if any step fails, the “rescuers” will repair the broken end to rescue chromosomal transformation. If the ssDNA does not share homology with resident DNA, but it contains information for autonomous replication, guardian and mediator proteins catalyze plasmid establishment after inhibition of RecA. DNA replication and ligation reconstitute the molecule (plasmid transformation). In this review, the interacting network that leads to a cross talk between proteins of the uptake and genetic recombination machinery will be placed into prospective. PMID:23046409

  3. Uptake of Human Papillomavirus Vaccine Among Adolescent Males and Females: Immunization Information System Sentinel Sites, 2009–2012

    PubMed Central

    Cullen, Karen A.; Stokley, Shannon; Markowitz, Lauri E.

    2015-01-01

    Objective The Advisory Committee on Immunization Practices (ACIP) has recommended routine human papillomavirus (HPV) vaccination at age 11 or 12 years for girls since 2006 and for boys since 2011. We sought to describe adolescent HPV vaccination coverage, doses administered from 2009 to 2012, and age at first vaccination by sex. Methods Aggregate data were analyzed from 8 Immunization Information System sentinel sites on HPV vaccinations in children and adolescents aged 11 to 12 years, 13 to 15 years, and 16 to 18 years. Vaccination coverage by age group was reported for 2009 to 2012, and weekly doses administered were determined. Age at first HPV vaccination was calculated for girls in 2007 and 2011 and for boys in 2011. Results This analysis included data on 2.9 million adolescents aged 11 to 18 years. There were small increases in coverage for girls, with receipt of ≥1 dose of HPV vaccine reaching 27.1% of ages 11 to 12, 47.9% of ages 13 to 15, and 57.1% of ages 16 to 18 by December 31, 2012. Uptake of ≥1 dose in boys reached ~18% for all age groups. Doses administered showed seasonal variation, with highest uptake before back to school among girls and steady increases in boys after the 2009 ACIP recommendation for permissive use. Doses administered to boys surpassed those administered to girls by September 2012. Among vaccinated girls, more received vaccine at the recommended age of 11 to 12 years in 2011 (74.2%) compared to 2007 (9.9%). In 2011, 27.3% of vaccinated boys received their first dose at age 11 to 12 years. Conclusions HPV vaccination coverage increased among adolescents between 2009 and 2012. However, increases among girls were small, and coverage for boys and girls remained below target levels. PMID:24954170

  4. Synaptic vesicles in electromotoneurones. I. Axonal transport, site of transmitter uptake and processing of a core proteoglycan during maturation.

    PubMed Central

    Kiene, M L; Stadler, H

    1987-01-01

    We were able by using an in vivo pulse-label technique to trace part of the life cycle of a secretory organelle, the acetylcholine-storing synaptic vesicle from electromotoneurones of Torpedo marmorata. This technique uses [35S]sulphate incorporation into the cell bodies of the electromotoneurones which results in radioactive labelling of a synaptic vesicle heparansulphate proteoglycan--a major core component. Vesicles are anterogradely transported in the axons at a fast rate as 'empty' organelles (VP0 population). In the nerve terminal, maturation of the granule to a population (VP1) fully charged with acetylcholine and ATP occurs. Finally after a longer time interval a change to a third population (VP2) is observed. This population is reduced in diameter as compared to VP0 and VP1 suggesting, in agreement with earlier reports, that it has undergone exo-endocytosis. The changes from VP0 to VP1 and VP2 are accompanied by a degradation of the core proteoglycan as measured by gel filtration of the 35S-labelled compound. The results show that vesicles are axonally transported as preformed organelles, exist in the neurone at least in three different populations and that the nerve terminal is the major site of transmitter uptake. Images Fig. 1. Fig. 4. Fig. 6. PMID:2444433

  5. Water structural changes at the proton uptake site (the Thr46-Asp96 domain) in the L intermediate of bacteriorhodopsin

    SciTech Connect

    Yamazaki, Yoichi; Hatanka, Minoru; Kandori, Hideki

    1995-05-30

    Fourier transform infrared spectra of the L intermediate of light-adapted bacteriorhodopsin were examined for recombinant proteins with amino acid substitutions at Thr46 and Asp96. Two O-H stretching vibrational bands of water, at 3607 and 3577 cm{sup -1}, change into stronger H-bonding states in L of the wild type. Thr46{r_arrow}Val substitution abolished these bands in spite of the fact that [3-{sup 18}O]threonine-labeling did not shift with them indicating that they correspond to coordination of the water with Thr46. The two water bands were restored, although with changed frequencies, by an additional Asp96{r_arrow}Asn substitution in Thr46{r_arrow}Val/Asp96{r_arrow}Asn. A single Asp96{r_arrow}Asn substitution abolished the 3607 cm{sup -1} band. Thus, Asp96 also takes part in structural changes in water. The perturbations of these water molecules in the L intermediate displayed a weak correlation with the ratio of intensity change in the two of vibrational bands of the Schiff base mode at 1312 and 1301 cm{sup -1} and the rate for the deprotonation of the Schiff base at the L-to-M reaction of the photocycle. We find, therefore, that the water molecule sin the cytoplasmic Asp96-Thr46 domain, which comprises the site of proton uptake after formation of the M intermediate, undergo structural changes in the L intermediate already. These changes are transmitted to the extracellular domain and the affect interaction of the Schiff base with Asp 85, that is far removed from this region. 32 refs., 7 figs.

  6. Metal uptake by homegrown vegetables – The relative importance in human health risk assessments at contaminated sites

    SciTech Connect

    Augustsson, Anna L.M.; Uddh-Söderberg, Terese E.; Hogmalm, K. Johan; Filipsson, Monika E.M.

    2015-04-15

    Risk assessments of contaminated land often involve the use of generic bioconcentration factors (BCFs), which express contaminant concentrations in edible plant parts as a function of the concentration in soil, in order to assess the risks associated with consumption of homegrown vegetables. This study aimed to quantify variability in BCFs and evaluate the implications of this variability for human exposure assessments, focusing on cadmium (Cd) and lead (Pb) in lettuce and potatoes sampled around 22 contaminated glassworks sites. In addition, risks associated with measured Cd and Pb concentrations in soil and vegetable samples were characterized and a probabilistic exposure assessment was conducted to estimate the likelihood of local residents exceeding tolerable daily intakes. The results show that concentrations in vegetables were only moderately elevated despite high concentrations in soil, and most samples complied with applicable foodstuff legislation. Still, the daily intake of Cd (but not Pb) was assessed to exceed toxicological thresholds for about a fifth of the study population. Bioconcentration factors were found to vary more than indicated by previous studies, but decreasing BCFs with increasing metal concentrations in the soil can explain why the calculated exposure is only moderately affected by the choice of BCF value when generic soil guideline values are exceeded and the risk may be unacceptable. - Highlights: • Uptake of Cd and Pb by lettuce and potatoes increased with soil contamination. • Consumption of homegrown vegetables may lead to a daily Cd intake above TDIs. • The variability in the calculated BCFs is high when compared to previous studies. • Exposure assessments are most sensitive to the choice of BCFs at low contamination.

  7. Comparison of modelled and measured ozone concentrations and meteorology for a site in south-west Sweden: implications for ozone uptake calculations.

    PubMed

    Klingberg, Jenny; Danielsson, Helena; Simpson, David; Pleijel, Håkan

    2008-09-01

    Measurements of ground-level ozone concentrations and meteorology (temperature, vapour pressure deficit (VPD), solar radiation) at the monitoring site Ostad (south-west Sweden) were compared to data from the corresponding grid in the EMEP photo-oxidant model for 1997, 1999 and 2000. The influence of synoptic weather on the agreement between model and measurements was studied. Implications of differences between modelled and observed inputs for ozone flux calculations for wheat and potato were investigated. The EMEP model output of ozone, temperature and VPD correlated well with measurements during daytime. Deviations were larger during the night, especially in calm conditions, attributed to local climatological conditions at the monitoring site deviating from average conditions of the grid. These differences did not lead to significant differences in calculated ozone uptake, which was reproduced remarkably well. The uptake calculations were sensitive to errors in the ozone and temperature input data, especially when including a flux threshold.

  8. The 5-hydroxytryptamine2A receptor antagonist R-(+)-alpha-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenyl)ethyl-4-piperidinemethanol (M100907) attenuates impulsivity after both drug-induced disruption (dizocilpine) and enhancement (antidepressant drugs) of differential-reinforcement-of-low-rate 72-s behavior in the rat.

    PubMed

    Ardayfio, Paul A; Benvenga, Mark J; Chaney, Stephen F; Love, Patrick L; Catlow, John; Swanson, Steven P; Marek, Gerard J

    2008-12-01

    Previous work has suggested that N-methyl-d-aspartate (NMDA) receptor antagonism and 5-hydroxytryptamine (5-HT)(2A) receptor blockade may enhance and attenuate, respectively, certain types of impulsivity mediated by corticothalamostriatal circuits. More specifically, past demonstrations of synergistic "antidepressant-like" effects of a 5-HT(2A) receptor antagonist and fluoxetine on differential-reinforcement-of-low-rate (DRL) 72-s schedule of operant reinforcement may speak to the role of 5-HT(2A) receptor blockade with respect to response inhibition as an important prefrontal cortical executive function relating to motor impulsivity. To examine the dynamic range over which 5-HT(2A) receptor blockade may exert effects on impulsivity, [R-(+)-alpha-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenyl)ethyl-4-piperidinemethanol] (M100907) was examined both alone and in combination with the psychotomimetic NMDA receptor antagonist dizocilpine [e.g., (-)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate; MK-801] and two different antidepressants, the tricyclic antidepressant desmethylimipramine (DMI) and the monoamine oxidase inhibitor tranylcypromine in rats performing under a DRL 72-s schedule. MK-801 increased the response rate, decreased the number of reinforcers obtained, and exerted a leftward shift in the inter-response time (IRT) distribution as expected. A dose of M100907 that exerted minimal effect on DRL behavior by itself attenuated the psychotomimetic effects of MK-801. Extending previous M100907-fluoxetine observations, addition of a minimally active dose of M100907 to low doses of DMI and tranylcypromine enhanced the antidepressant-like effect of the antidepressants. Therefore, it may be that a tonic excitation of 5-HT(2A) receptors modulates impulsivity and function of corticothalamostriatal circuits over an extensive dynamic range. PMID:18772320

  9. 5-Amino-6-chloro-N-[(1-isobutylpiperidin-4-yl)methyl]-2-methylimidazo[1,2-alpha]pyridine-8-carboxamide (CJ-033,466), a novel and selective 5-hydroxytryptamine4 receptor partial agonist: pharmacological profile in vitro and gastroprokinetic effect in conscious dogs.

    PubMed

    Mikami, Tadayoshi; Ochi, Yasuo; Suzuki, Keiko; Saito, Toshiyuki; Sugie, Yutaka; Sakakibara, Minoru

    2008-04-01

    5-Hydroxytryptamine (5-HT) receptors and dopamine(2) (D(2)) receptor modulate gastrointestinal motility. Gastroprokinetic agents that act on several 5-HT receptor subtypes and/or D(2) receptors are used clinically. Although the 5-HT(4) receptor is known to mediate the gastroprokinetic effects of these agents, the absence of highly selective 5-HT(4) receptor agonists has made it difficult to confirm the physiological consequences of selective 5-HT(4) receptor stimulation. In this study, we report the in vitro pharmacological profiles and the in vivo gastroprokinetic effects of 5-amino-6-chloro-N-[(1-isobutylpiperidin-4-yl)methyl]-2-methylimidazo[1,2-alpha]pyridine-8-carboxamide (CJ-033,466), a novel, potent, and selective 5-HT(4) partial agonist. Compared with preceding 5-HT(4) agonists such as cisapride, mosapride, and tegaserod, CJ-033,466 had a superior in vitro profile, with nanomolar agonistic activities for the 5-HT(4) receptor and 1000-fold greater selectivity for the 5-HT(4) receptor over other 5-HT and D(2) receptors. In vivo studies in conscious dogs showed that CJ-033,466 dose-dependently stimulated gastric antral motility in both the fasted and postprandial states at the same dose range and that it was 30 times more potent than cisapride. Furthermore, CJ-033,466 accelerated the gastric emptying rate in a gastroparesis dog model at the minimally effective dose established in the gastric motility study. In conclusion, CJ-033,466 is a potent and highly selective 5-HT(4) agonist that stimulates physiologically coordinated gastric motility, and it has no activity on other 5-HT receptor subtypes and D(2) receptors. Therefore, CJ-033,466 could be used to treat gastroparesis, providing better gastroprokinetics and reduced side effects mediated by the other receptors. PMID:18198343

  10. Contaminant Uptake and Demography of the Loggerhead Shrike (Lanius ludovicianus) at the Lawrence Livermore National Laboratory, Site 300

    SciTech Connect

    van Hattem, M G; Santolo, G

    2005-02-23

    Concentrations of eleven potential environmental contaminants (metals) in the blood and retrice feathers of fledged-Hatch Year and adult loggerhead shrikes (Lanius ludovicianus) were examined at Lawrence Livermore National Laboratory's Site 300 and a control site, in San Joaquin and Contra Costa Counties, California. The purpose of this pilot study was to determine, through non-lethal means, if loggerhead shrikes are exposed to metals at Site 300 and whether specific demographic variables (i.e., clutch size, fledgling success, etc.) are affected. Loggerhead shrikes at Site 300 had higher blood concentrations of metals, especially birds on the west side of the site, when compared to control site birds. Metal concentrations in the feathers of control site birds tended to be higher than Site 300 shrikes. Blood concentrations of metals in loggerhead shrikes from both Site 300 and the control site were well below the Most Tolerant Dietary Level (MTDL) for domestic birds for all metals except selenium. Clutch size was similar to other populations but one deformed embryo was discovered in a failed egg. The results of this pilot study suggest further work is needed to understand possible synergistic effects related to other contaminants of concern found at Site 300 and overall population variability.

  11. Siderophore-mediated iron uptake in fluorescent Pseudomonas: characterization of the pyoverdine-receptor binding site of three cross-reacting pyoverdines.

    PubMed

    Meyer, Jean-Marie; Geoffroy, Valérie A; Baysse, Christine; Cornelis, Pierre; Barelmann, Insa; Taraz, Kambiz; Budzikiewicz, Herbert

    2002-01-15

    Two Pseudomonas fluorescens and one Pseudomonas aeruginosa strains, although producing structurally different pyoverdines, demonstrated highly efficient cross-reactions when tested for pyoverdine-mediated iron uptake. A ferripyoverdine receptor-deficient mutant of the P. aeruginosa strain was unable to use any of the three pyoverdines. Moreover, the three strains presented each a specific outer membrane siderophore-receptor pattern. Thus, the capacity of using heterologous pyoverdines was related not to the presence of supplementary specific ferripyoverdine receptors but to the existence within the respective pyoverdine-peptide chains of a common dipeptide motif which should act as the receptor-binding site for the three pyoverdines. Other pyoverdines sharing the same motif but at another position within the peptide chain were not efficient in iron transport, demonstrating the importance of the spatial position of the binding site. PMID:11795869

  12. Grass species influence on plant N uptake - Determination of atmospheric N deposition to a semi-natural peat bog site using a 15N labelling approach

    NASA Astrophysics Data System (ADS)

    Hurkuck, Miriam; Brümmer, Christian; Spott, Oliver; Flessa, Heinz; Kutsch, Werner L.

    2014-05-01

    Large areas of natural peat bogs in Northwestern Germany have been converted to arable land and were subjected to draining and peat cutting in the past. The few protected peatland areas remaining are affected by high nitrogen (N) deposition. Our study site - a moderately drained raised bog - is surrounded by highly fertilized agricultural land and livestock production. In this study, we used a 15N pool dilution technique called 'Integrated Total Nitrogen Input' (ITNI) to quantify annual deposition of atmospheric N into biomonitoring pots over a two-year period. Since it considers direct N uptake by plants, it was expected to result in higher N input than conventional methods for determination of N deposition (e.g. micrometeorological approaches, bulk N samplers). Using Lolium multiflorum and Eriophorum vaginatum as monitor plants and low, medium and high levels of fertilization, we aimed to simulate increasing N deposition to planted pots and to allocate airborne N after its uptake by the soil-plant system in aboveground biomass, roots and soil. Increasing N fertilization was positively correlated with biomass production of Eriophorum vaginatum, whereas atmospheric plant N uptake decreased and highest airborne N input of 899.8 ± 67.4 µg N d-1 pot-1 was found for low N fertilization. In contrast, Lolium multiflorum showed a clear dependency of N supply on plant N uptake and was highest (688.7 ± 41.4 µg N d-1 pot-1) for highly fertilized vegetation pots. Our results suggest that grass species respond differently to increasing N input. While crop grasses such as Lolium multiflorum take up N according to N availability, species adopted to nutrient-limited conditions like Eriophorum vaginatum show N saturation effects with increasing N supply. Total airborne N input ranged from about 24 to 66 kg N ha-1 yr-1 dependent on the used indicator plant and the amount of added fertilizer. Parallel determination of atmospheric N deposition using a micrometeorological approach

  13. Endogenous 5-HT outflow from chicken aorta by 5-HT uptake inhibitors and amphetamine derivatives

    PubMed Central

    DELGERMURUN, Dugar; ITO, Shigeo; OHTA, Toshio; YAMAGUCHI, Soichiro; OTSUGURO, Ken-ichi

    2015-01-01

    Chemoreceptor cells aggregating in clusters in the chicken thoracic aorta contain 5-hydroxytryptamine (5-HT) and have voltage-dependent ion channels and nicotinic acetylcholine receptors, which are characteristics typically associated with neurons. The aim of the present study was to investigate the effects of 5-HT uptake inhibitors, fluvoxamine, fluoxetine and clomipramine (CLM), and amphetamine derivatives, p-chloroamphetamine (PCA) and methamphetamine (MET), on endogenous 5-HT outflow from the isolated chick thoracic aorta in vitro. 5-HT was measured by using a HPLC system with electrochemical detection. The amphetamine derivatives and 5-HT uptake inhibitors caused concentration-dependent increases in endogenous 5-HT outflow. PCA was about ten times more effective in eliciting 5-HT outflow than MET. The 5-HT uptake inhibitors examined had similar potency for 5-HT outflow. PCA and CLM increased 5-HT outflow in a temperature-dependent manner. The outflow of 5-HT induced by PCA or 5-HT uptake inhibitors was independent of extracellular Ca2+ concentration. The 5-HT outflow induced by CLM, but not that by PCA, was dependent on the extracellular NaCl concentration. These results suggest that the 5-HT uptake system of 5-HT-containing chemoreceptor cells in the chicken thoracic aorta has characteristics similar to those of 5-HT-containing neurons in the mammalian central nervous system (CNS). PMID:26321443

  14. Differential effects of the 5-hydroxytryptamine (5-HT)1A receptor inverse agonists Rec 27/0224 and Rec 27/0074 on electrophysiological responses to 5-HT1A receptor activation in rat dorsal raphe nucleus and hippocampus in vitro.

    PubMed

    Corradetti, Renato; Mlinar, Boris; Falsini, Chiara; Pugliese, Anna Maria; Cilia, Antonio; Destefani, Carla; Testa, Rodolfo

    2005-10-01

    The pharmacological properties of cyclohexanecarboxylic acid, {2-[4-(2-bromo-5-methoxybenzyl)piperazin-1-yl]ethyl}-(2-trifluoromethoxyphenyl)amide (Rec 27/0224), and cyclohexanecarboxylic acid, (2-methoxy-phenyl)-{2-[4-(2-methoxyphenyl)-piperazin-1-yl]ethyl}amide (Rec 27/0074), were characterized using radioligand displacement and guanosine 5'-O-(3-[35S]thiotriphosphate) ([35S]GTPgammaS) binding assays, as well as electrophysiological experiments, in rat hippocampal and dorsal raphe nucleus (DRN) slices. Both compounds showed a high affinity (Ki, approximately 1 nM) and selectivity (>70-fold) at human 5-hydroxytryptamine (5-HT)1A receptors versus other 5-HT receptors. In [35S]GTPgammaS binding assays on HeLa cells stably expressing human 5-HT1A receptors, Rec 27/0224 and Rec 27/0074 inhibited basal [35S]GTPgammaS binding by 44.8 +/- 1.7% (pEC50 = 8.58) and 25 +/- 2.5% (pEC50 = 8.86), respectively. In intracellularly recorded CA1 pyramidal cells, 5-HT1A (hetero)receptor-mediated hyperpolarization, elicited by 100 nM 5-carboxamidoytryptamine (5-CT), was partially antagonized by Rec 27/0224 (approximately 50%; IC50 = 18.0 nM) and Rec 27/0074 (74%; IC50 = 0.8 nM). In extracellularly recorded DRN serotonergic neurons, Rec 27/0224 and Rec 27/0074 fully antagonized the inhibition of firing caused by the activation of 5-HT1A (auto)receptors by 30 nM 5-CT with an IC50 of 34.9 nM and 16.5 nM, respectively. The antagonism had a slow time course, reaching a steady state within 60 min. Both compounds also antagonized the citalopram-elicited, endogenous 5-HT-mediated inhibition of cell firing. In conclusion, Rec 27/0224 and Rec 27/0074 exhibited inverse agonism in [35S]GTPgammaS binding assays and differential antagonistic properties on 5-HT1A receptor-mediated responses in the hippocampus but not in the DRN. Whether this differential effect is causally related to inverse agonist activity is unclear. The qualitatively different nature of the antagonism in the hippocampus versus

  15. Increasing Healthy Start food and vitamin voucher uptake for low income pregnant women (Early Years Collaborative Leith Pioneer Site)

    PubMed Central

    Mackenzie, Graham; Dougall, Angela

    2016-01-01

    Poverty has a detrimental impact on health and wellbeing. Healthy Start food and vitamin vouchers provide support for low income families across the UK, but at least 25% of eligible women and children miss out. We set out to increase uptake, with an aim of 90% of eligible women and children (n~540 eligible, varying over time) receiving vouchers in the initial team's catchment area by December 2015. Starting with one midwife and one pregnant woman in March 2014 we used the model for improvement to identify ways to improve documentation, sign up, and referral. Weekly data on process measures and monthly data on voucher receipt were plotted on run charts. Comparing medians for January-June 2014 and March-August 2015 there was a 13.3% rise in voucher receipt in Lothian (increase from 313 to 355 women), versus an 8.4% decline for the rest of Scotland (fall from 1688 to 1546 women). Figures varied by team, influenced by staff, family, and area factors. The initial aim proved unrealistic, as signing up a woman for vouchers increases both the numerator and denominator. Accordingly, the percentage uptake has not increased at a regional level (remains at 75%), though the figure for the initiating team (“team 3” in graphs) has increased from 73.0% (January 2014) to 79.0% (November 2015). We have continued testing, achieving recent increases in the number of women referred for welfare rights advice on benefits, tax credits, employment rights, childcare, and debt, securing on average £4,500 per client during 2015/16 (£404k for 89 clients by mid September 2015). This improvement project, part of the Early Years Collaborative in Scotland, has had a measureable impact on pregnant women across Lothian. Success has relied on testing, an electronic maternity record, rapid dissemination of findings through direct engagement with clinical teams, and persistence. Our findings have relevance across the UK, particularly at a time of worsening finances for many families. PMID

  16. Increasing Healthy Start food and vitamin voucher uptake for low income pregnant women (Early Years Collaborative Leith Pioneer Site).

    PubMed

    Mackenzie, Graham; Dougall, Angela

    2016-01-01

    Poverty has a detrimental impact on health and wellbeing. Healthy Start food and vitamin vouchers provide support for low income families across the UK, but at least 25% of eligible women and children miss out. We set out to increase uptake, with an aim of 90% of eligible women and children (n~540 eligible, varying over time) receiving vouchers in the initial team's catchment area by December 2015. Starting with one midwife and one pregnant woman in March 2014 we used the model for improvement to identify ways to improve documentation, sign up, and referral. Weekly data on process measures and monthly data on voucher receipt were plotted on run charts. Comparing medians for January-June 2014 and March-August 2015 there was a 13.3% rise in voucher receipt in Lothian (increase from 313 to 355 women), versus an 8.4% decline for the rest of Scotland (fall from 1688 to 1546 women). Figures varied by team, influenced by staff, family, and area factors. The initial aim proved unrealistic, as signing up a woman for vouchers increases both the numerator and denominator. Accordingly, the percentage uptake has not increased at a regional level (remains at 75%), though the figure for the initiating team ("team 3" in graphs) has increased from 73.0% (January 2014) to 79.0% (November 2015). We have continued testing, achieving recent increases in the number of women referred for welfare rights advice on benefits, tax credits, employment rights, childcare, and debt, securing on average £4,500 per client during 2015/16 (£404k for 89 clients by mid September 2015). This improvement project, part of the Early Years Collaborative in Scotland, has had a measureable impact on pregnant women across Lothian. Success has relied on testing, an electronic maternity record, rapid dissemination of findings through direct engagement with clinical teams, and persistence. Our findings have relevance across the UK, particularly at a time of worsening finances for many families. PMID:27134747

  17. Site-specific conjugation of single domain antibodies to liposomes enhances photosensitizer uptake and photodynamic therapy efficacy

    NASA Astrophysics Data System (ADS)

    Broekgaarden, M.; van Vught, R.; Oliveira, S.; Roovers, R. C.; van Bergen En Henegouwen, P. M. P.; Pieters, R. J.; van Gulik, T. M.; Breukink, E.; Heger, M.

    2016-03-01

    Photodynamic therapy for therapy-resistant cancers will greatly benefit from targeted delivery of tumor photosensitizing agents. In this study, a strategy for the site-specific conjugation of single domain antibodies onto liposomes containing the photosensitizer zinc phthalocyanine was developed and tested.Photodynamic therapy for therapy-resistant cancers will greatly benefit from targeted delivery of tumor photosensitizing agents. In this study, a strategy for the site-specific conjugation of single domain antibodies onto liposomes containing the photosensitizer zinc phthalocyanine was developed and tested. Electronic supplementary information (ESI) available: Materials and methods. See DOI: 10.1039/c6nr00014b

  18. Evidence for regional catecholamine uptake and storage sites in the transplanted human heart by positron emission tomography

    SciTech Connect

    Schwaiger, M.; Hutchins, G.D.; Kalff, V.; Rosenspire, K.; Haka, M.S.; Mallette, S.; Deeb, G.M.; Abrams, G.D.; Wieland, D. )

    1991-05-01

    Positron emission tomography in combination with the newly introduced catecholamine analogue ({sup 11}C)hydroxyephedrine (({sup 11}C)HED) enables the noninvasive delineation of sympathetic nerve terminals of the heart. To address the ongoing controversy over possible reinnervation of the human transplant, 5 healthy control subjects and 11 patients were studied after cardiac transplant by this imaging approach. Regional ({sup 11}C)HED retention was compared to regional blood flow as assessed by rubidium-82. Transplant patients were divided into two groups. Group I had recent (less than 1 yr, 4.4 +/- 2.3 mo) surgery, while group II patients underwent cardiac transplantation more than 2 yr before imaging (3.5 +/- 1.3 yr). ({sup 11}C)HED retention paralleled blood flow in normals, but was homogeneously reduced in group I. In contrast, group II patients revealed heterogeneous ({sup 11}C)HED retention, with increased uptake in the proximal anterior and septal wall. Quantitative evaluation of ({sup 11}C)HED retention revealed a 70% reduction in group I and 59% reduction in group II patients (P less than 0.001). In group II patients, ({sup 11}C)HED retention reached 60% of normal in the proximal anterior wall. These data suggest the presence of neuronal tissue in the transplanted human heart, which may reflect regional sympathetic reinnervation.

  19. SITE SITE DISTURBANCE EFFECTS ON A CLAY SOIL UNDER PINUS RADIATA - ROOT BIOMASS, MYCORRHIZAL COLONISATION, 15AMMONIUM UPTAKE, AND FOLIAR NUTRIENT LEVELS

    EPA Science Inventory

    Timber harvesting can result in adverse physical, chemical and biological alterations to soil. The objective of this study was to examine the effects of site disturbance to determine the extent and duration of possible harvesting impacts on soil chemical and biological propertie...

  20. Ligand uptake in Mycobacterium tuberculosis truncated hemoglobins is controlled by both internal tunnels and active site water molecules

    PubMed Central

    Davidge, Kelly S; Singh, Sandip; Bowman, Lesley AH; Tinajero-Trejo, Mariana; Carballal, Sebastián; Radi, Rafael; Poole, Robert K; Dikshit, Kanak; Estrin, Dario A; Marti, Marcelo A; Boechi, Leonardo

    2015-01-01

    Mycobacterium tuberculosis, the causative agent of human tuberculosis, has two proteins belonging to the truncated hemoglobin (trHb) family. Mt-trHbN presents well-defined internal hydrophobic tunnels that allow O 2 and •NO to migrate easily from the solvent to the active site, whereas Mt-trHbO possesses tunnels that are partially blocked by a few bulky residues, particularly a tryptophan at position G8. Differential ligand migration rates allow Mt-trHbN to detoxify •NO, a crucial step for pathogen survival once under attack by the immune system, much more efficiently than Mt-trHbO. In order to investigate the differences between these proteins, we performed experimental kinetic measurements, •NO decomposition, as well as molecular dynamics simulations of the wild type Mt-trHbN and two mutants, VG8F and VG8W. These mutations introduce modifications in both tunnel topologies and affect the incoming ligand capacity to displace retained water molecules at the active site. We found that a single mutation allows Mt-trHbN to acquire ligand migration rates comparable to those observed for Mt-trHbO, confirming that ligand migration is regulated by the internal tunnel architecture as well as by water molecules stabilized in the active site. PMID:26478812

  1. Ligand uptake in Mycobacterium tuberculosis truncated hemoglobins is controlled by both internal tunnels and active site water molecules.

    PubMed

    Boron, Ignacio; Bustamante, Juan Pablo; Davidge, Kelly S; Singh, Sandip; Bowman, Lesley Ah; Tinajero-Trejo, Mariana; Carballal, Sebastián; Radi, Rafael; Poole, Robert K; Dikshit, Kanak; Estrin, Dario A; Marti, Marcelo A; Boechi, Leonardo

    2015-01-01

    Mycobacterium tuberculosis, the causative agent of human tuberculosis, has two proteins belonging to the truncated hemoglobin (trHb) family. Mt-trHbN presents well-defined internal hydrophobic tunnels that allow O 2 and (•)NO to migrate easily from the solvent to the active site, whereas Mt-trHbO possesses tunnels that are partially blocked by a few bulky residues, particularly a tryptophan at position G8. Differential ligand migration rates allow Mt-trHbN to detoxify (•)NO, a crucial step for pathogen survival once under attack by the immune system, much more efficiently than Mt-trHbO. In order to investigate the differences between these proteins, we performed experimental kinetic measurements, (•)NO decomposition, as well as molecular dynamics simulations of the wild type Mt-trHbN and two mutants, VG8F and VG8W. These mutations introduce modifications in both tunnel topologies and affect the incoming ligand capacity to displace retained water molecules at the active site. We found that a single mutation allows Mt-trHbN to acquire ligand migration rates comparable to those observed for Mt-trHbO, confirming that ligand migration is regulated by the internal tunnel architecture as well as by water molecules stabilized in the active site.

  2. Did we choose the best one? A new site selection approach based on exposure and uptake potential for waste incineration.

    PubMed

    Demirarslan, K Onur; Korucu, M Kemal; Karademir, Aykan

    2016-08-01

    Ecological problems arising after the construction and operation of a waste incineration plant generally originate from incorrect decisions made during the selection of the location of the plant. The main objective of this study is to investigate how the selection method for the location of a new municipal waste incineration plant can be improved by using a dispersion modelling approach supported by geographical information systems and multi-criteria decision analysis. Considering this aim, the appropriateness of the current location of an existent plant was assessed by applying a pollution dispersion model. Using this procedure, the site ranking for a total of 90 candidate locations and the site of the existing incinerator were determined by a new location selection practice and the current place of the plant was evaluated by ANOVA and Tukey tests. This ranking, made without the use of modelling approaches, was re-evaluated based on the modelling of various variables, including the concentration of pollutants, population and population density, demography, temporality of meteorological data, pollutant type, risk formation type by CALPUFF and re-ranking the results. The findings clearly indicate the impropriety of the location of the current plant, as the pollution distribution model showed that its location was the fourth-worst choice among 91 possibilities. It was concluded that the location selection procedures for waste incinerators should benefit from the improvements obtained by the articulation of pollution dispersion studies combined with the population density data to obtain the most suitable location.

  3. Did we choose the best one? A new site selection approach based on exposure and uptake potential for waste incineration.

    PubMed

    Demirarslan, K Onur; Korucu, M Kemal; Karademir, Aykan

    2016-08-01

    Ecological problems arising after the construction and operation of a waste incineration plant generally originate from incorrect decisions made during the selection of the location of the plant. The main objective of this study is to investigate how the selection method for the location of a new municipal waste incineration plant can be improved by using a dispersion modelling approach supported by geographical information systems and multi-criteria decision analysis. Considering this aim, the appropriateness of the current location of an existent plant was assessed by applying a pollution dispersion model. Using this procedure, the site ranking for a total of 90 candidate locations and the site of the existing incinerator were determined by a new location selection practice and the current place of the plant was evaluated by ANOVA and Tukey tests. This ranking, made without the use of modelling approaches, was re-evaluated based on the modelling of various variables, including the concentration of pollutants, population and population density, demography, temporality of meteorological data, pollutant type, risk formation type by CALPUFF and re-ranking the results. The findings clearly indicate the impropriety of the location of the current plant, as the pollution distribution model showed that its location was the fourth-worst choice among 91 possibilities. It was concluded that the location selection procedures for waste incinerators should benefit from the improvements obtained by the articulation of pollution dispersion studies combined with the population density data to obtain the most suitable location. PMID:27354016

  4. An evaluation of the regional acid deposition model surface module for ozone uptake at three sites in the San Joaquin Valley of California

    NASA Technical Reports Server (NTRS)

    Massman, W. J.; Pederson, J.; Delany, A.; Grantz, D.; Hertog, G. Den; Neumann, H. H.; Oncley, S. P.; Pearson, R., Jr.; Shaw, R. H.

    1994-01-01

    Plants and soils act as major sinks for the destruction of tropospheric ozone, especially during daylight hours when plant stomata open and are thought to provide the dominant pathway for the uptake of ozone. The present study, part of the California Ozone Deposition Experiment, compares predictions of the regional acid deposition model ozone surface conductance module with surface conductance data derived from eddy covariance measurements of ozone flux taken at a grape, a cotton, and a grassland site in the San Joaquin Valley of California during the summer of 1991. Results indicate that the model (which was developed to provide long-term large-area estimates for the eastern United States) significantly overpredicts the surface conductance at all times of the day for at least two important types of plant cover of the San Joaquin Valley and that it incorrectly partitions the ozone flux between transpiring and nontranspiring components of the surface at the third site. Consequently, the model either overpredicts or inaccurately represents the observed deposition velocities. Other results indicate that the presence of dew does not reduce the rate of ozone deposition, contradicting to model assumptions, and that model assumptions involving the dependency of stomata upon environmental temperature are unnecessary. The effects of measurement errors and biases, arising from the presence of the roughness sublayer and possible photochemical reactions, are also discussed. A simpler model for ozone surface deposition (at least for the San Joaquin Valley) is proposed and evaluated.

  5. Cadmium and zinc uptake by volunteer willow species and elder rooting in polluted dredged sediment disposal sites.

    PubMed

    Vandecasteele, Bart; De Vos, Bruno; Tack, Filip M G

    2002-11-01

    Salix species and Sambucus nigra L. (elder) naturally invade dredged sediment landfills and are commonly encountered on substrates contaminated with heavy metals. Foliar concentrations of Cd and Zn in four Salix species and elder were explored in the field. Metal contents in dredged sediment derived soils were elevated compared to baseline concentration levels reported for Flanders. To evaluate foliar concentrations, reference data were compiled from observations in nurseries, young plantations and unpolluted sites with volunteer willow vegetation. Willows grown on polluted dredged sediment landfills showed elevated foliar Cd and Zn concentrations (>6.6 mg Cd/kg DW and >700 mg Zn/kg DW). This was not the case for elder. For willow, a significant relation was found between soil total Zn or Cd and foliar Zn or Cd, regardless of age, species, or clone. Willows proved to be useful bioindicators. Results indicated a possible threat in long-term habitat development of willow brushwood from transfer of Cd and Zn to the food web.

  6. Random and site-specific mutagenesis of the Helicobacter pylori ferric uptake regulator provides insight into Fur structure-function relationships.

    PubMed

    Gilbreath, Jeremy J; Pich, Oscar Q; Benoit, Stéphane L; Besold, Angelique N; Cha, Jeong-Heon; Maier, Robert J; Michel, Sarah L J; Maynard, Ernest L; Merrell, D Scott

    2013-07-01

    The ferric uptake regulator (Fur) of Helicobacter pylori is a global regulator that is important for colonization and survival within the gastric mucosa. H. pylori Fur is unique in its ability to activate and repress gene expression in both the iron-bound (Fe-Fur) and apo forms (apo-Fur). In the current study we combined random and site-specific mutagenesis to identify amino acid residues important for both Fe-Fur and apo-Fur function. We identified 25 mutations that affected Fe-Fur repression and 23 mutations that affected apo-Fur repression, as determined by transcriptional analyses of the Fe-Fur target gene amiE, and the apo-Fur target gene, pfr. In addition, eight of these mutations also significantly affected levels of Fur in the cell. Based on regulatory phenotypes, we selected several representative mutations to characterize further. Of those selected, we purified the wild-type (HpFurWT) and three mutant Fur proteins (HpFurE5A, HpFurA92T and HpFurH134Y), which represent mutations in the N-terminal extension, the regulatory metal binding site (S2) and the structural metal binding site (S3) respectively. Purified proteins were evaluated for secondary structure by circular dichroism spectroscopy, iron-binding by atomic absorption spectrophotometry, oligomerization in manganese-substituted and apo conditions by in vitro cross-linking assays, and DNA binding to Fe-Fur and apo-Fur target sequences by fluorescence anisotropy. The results showed that the N-terminal, S2 and S3 regions play distinct roles in terms of Fur structure-function relationships. Overall, these studies provide novel information regarding the role of these residues in Fur function, and provide mechanistic insight into how H. pylori Fur regulates gene expression in both the iron-bound and apo forms of the protein.

  7. Random and site-specific mutagenesis of the Helicobacter pylori ferric uptake regulator provides insight into Fur structure-function relationships.

    PubMed

    Gilbreath, Jeremy J; Pich, Oscar Q; Benoit, Stéphane L; Besold, Angelique N; Cha, Jeong-Heon; Maier, Robert J; Michel, Sarah L J; Maynard, Ernest L; Merrell, D Scott

    2013-07-01

    The ferric uptake regulator (Fur) of Helicobacter pylori is a global regulator that is important for colonization and survival within the gastric mucosa. H. pylori Fur is unique in its ability to activate and repress gene expression in both the iron-bound (Fe-Fur) and apo forms (apo-Fur). In the current study we combined random and site-specific mutagenesis to identify amino acid residues important for both Fe-Fur and apo-Fur function. We identified 25 mutations that affected Fe-Fur repression and 23 mutations that affected apo-Fur repression, as determined by transcriptional analyses of the Fe-Fur target gene amiE, and the apo-Fur target gene, pfr. In addition, eight of these mutations also significantly affected levels of Fur in the cell. Based on regulatory phenotypes, we selected several representative mutations to characterize further. Of those selected, we purified the wild-type (HpFurWT) and three mutant Fur proteins (HpFurE5A, HpFurA92T and HpFurH134Y), which represent mutations in the N-terminal extension, the regulatory metal binding site (S2) and the structural metal binding site (S3) respectively. Purified proteins were evaluated for secondary structure by circular dichroism spectroscopy, iron-binding by atomic absorption spectrophotometry, oligomerization in manganese-substituted and apo conditions by in vitro cross-linking assays, and DNA binding to Fe-Fur and apo-Fur target sequences by fluorescence anisotropy. The results showed that the N-terminal, S2 and S3 regions play distinct roles in terms of Fur structure-function relationships. Overall, these studies provide novel information regarding the role of these residues in Fur function, and provide mechanistic insight into how H. pylori Fur regulates gene expression in both the iron-bound and apo forms of the protein. PMID:23710935

  8. Random and Site-Specific Mutagenesis of the Helicobacter pylori Ferric Uptake Regulator Provides Insight into Fur Structure-Function Relationships

    PubMed Central

    Gilbreath, Jeremy J.; Pich, Oscar Q.; Benoit, Stéphane L.; Besold, Angelique N.; Cha, Jeong-Heon; Maier, Robert J.; Michel, Sarah L.J.; Maynard, Ernest L.; Merrell, D. Scott

    2013-01-01

    Summary The ferric uptake regulator (Fur) of Helicobacter pylori is a global regulator that is important for colonization and survival within the gastric mucosa. H. pylori Fur is unique in its ability to activate and repress gene expression in both the iron-bound (Fe-Fur) and apo forms (apo-Fur). In the current study we combined random and site-specific mutagenesis to identify amino acid residues important for both Fe-Fur and apo-Fur function. We identified 25 mutations that affected Fe-Fur repression and 23 mutations that affected apo-Fur repression, as determined by transcriptional analyses of the Fe-Fur target gene amiE, and the apo-Fur target gene, pfr. In addition, eight of these mutations also significantly affected levels of Fur in the cell. Based on regulatory phenotypes, we selected several representative mutations to characterize further. Of those selected, we purified the wildtype (HpFurWT) and three mutant Fur proteins (HpFurE5A, HpFurA92T, and HpFurH134Y), which represent mutations in the N-terminal extension, the regulatory metal binding site (S2) and the structural metal binding site (S3), respectively. Purified proteins were evaluated for secondary structure by circular dichroism spectroscopy, iron-binding by atomic absorption spectrophotometry, oligomerization in iron-substituted and apo conditions by in vitro cross-linking assays, and DNA binding to Fe-Fur and apo-Fur target sequences by fluorescence anisotropy. The results showed that the N-terminal, S2, and S3 regions play distinct roles in terms of Fur structure-function relationships. Overall, these studies provide novel information regarding the role of these residues in Fur function, and provide mechanistic insight into how H. pylori Fur regulates gene expression in both the iron-bound and apo forms of the protein. PMID:23710935

  9. 3,4-Methylenedioxymethamphetamine and 3,4-methylenedioxyamphetamine destroy serotonin terminals in rat brain: quantification of neurodegeneration by measurement of (/sup 3/H)paroxetine-labeled serotonin uptake sites

    SciTech Connect

    Battaglia, G.; Yeh, S.Y.; O'Hearn, E.; Molliver, M.E.; Kuhar, M.J.; De Souza, E.B.

    1987-09-01

    This study examines the effects of repeated systemic administration (20 mg/kg s.c., twice daily for 4 days) of 3,4-methylenedioxymethamphetamine (MDMA) and 3,4-methylenedioxyamphetamine (MDA) on levels of brain monoamines, their metabolites and on the density of monoamine uptake sites in various regions of rat brain. Marked reductions (30-60%) in the concentration of 5-hydroxyindoleacetic acid were observed in cerebral cortex, hippocampus, striatum, hypothalamus and midbrain at 2 weeks after a 4-day treatment regimen of MDMA or MDA; less consistent reductions in serotonin (5-HT) content were observed in these brain regions. In addition, both MDMA and MDA caused comparable and substantial reductions (50-75%) in the density of (/sup 3/H)paroxetine-labeled 5-HT uptake sites in all brain regions examined. In contrast, neither MDMA nor MDA caused any widespread or long-term changes in the content of the catecholaminergic markers (i.e., norepinephrine, dopamine, 3,4 dihydroxyphenylacetic acid and homovanillic acid) or in the number of (/sup 3/H)mazindol-labeled norepinephrine or dopamine uptake sites in the brain regions examined. These data demonstrate that MDMA and MDA cause long-lasting neurotoxic effects with respect to both the functional and structural integrity of serotonergic neurons in brain. Furthermore, our measurement of reductions in the density of 5-HT uptake sites provides a means for quantification of the neurodegenerative effects of MDMA and MDA on presynaptic 5-HT terminals.

  10. Site-specific conjugation of monodispersed DOTA-PEGn to a thiolated diabody reveals the effect of increasing peg size on kidney clearance and tumor uptake with improved 64-copper PET imaging.

    PubMed

    Li, Lin; Crow, Desiree; Turatti, Fabio; Bading, James R; Anderson, Anne-Line; Poku, Erasmus; Yazaki, Paul J; Carmichael, Jenny; Leong, David; Wheatcroft, David; Wheatcroft, Michael P; Raubitschek, Andrew A; Hudson, Peter J; Colcher, David; Shively, John E

    2011-04-20

    Optimal PET imaging of tumors with radiolabeled engineered antibodies requires, among other parameters, matching blood clearance and tumor uptake with the half-life of the engineered antibody. Although diabodies have favorable molecular sizes (50 kDa) for rapid blood clearance (t(1/2) = 30-60 min) and are bivalent, thereby increasing tumor uptake, they exhibit substantial kidney uptake as their major route of clearance, which is especially evident when they are labeled with the PET isotope (64)Cu (t(1/2) = 12 h). To overcome this drawback, diabodies may be conjugated to PEG, a modification that increases the apparent molecular size of the diabody and reduces kidney uptake without adversely affecting tumor uptake or the tumor to blood ratio. We show here that site-specific attachment of monodispersed PEGn of increasing molecular size (n = 12, 24, and 48) can uniformly increase the apparent molecular size of the PEG-diabody conjugate, decrease kidney uptake, and increase tumor uptake, the latter due to the increased residence time of the conjugate in the blood. Since the monodispersed PEGs were preconjugated to the chelator DOTA, the conjugates were able to bind radiometals such as (111)In and (64)Cu that can be used for SPECT and PET imaging, respectively. To allow conjugation of the DOTA-PEG to the diabody, the DOTA-PEG incorporated a terminal cysteine conjugated to a vinyl sulfone moiety. In order to control the conjugation chemistry, we have engineered a surface thiolated diabody that incorporates two cysteines per monomer (four per diabody). The thiolated diabody was expressed and purified from bacterial fermentation and only needs to be reduced prior to conjugation to the DOTA-PEGn-Cys-VS. This novel imaging agent (a diabody with DOTA-PEG48-Cys-VS attached to introduced thiols) gave up to 80%ID/g of tumor uptake with a tumor to blood ratio (T/B) of 8 at 24 h when radiolabeled with (111)In and 37.9% ID/g of tumor uptake (T/B = 8) at 44 h when radiolabeled with

  11. Uptake of strontium by chamisa (Chrysothamnus nauseosus) shrub plants growing over a former liquid waste disposal site at Los Alamos National Laboratory

    SciTech Connect

    Fresquez, P.R.; Foxx, T.S.; Naranjo, L. Jr.

    1996-06-01

    A major concern of managers at low-level waste burial site facilities is that plant roots may translocate contaminants up to the soil surface. This study investigates the uptake of strontium ({sup 90}Sr), a biologically mobile element, by chamisa (Chrysothamnus nauseosus), a deep-rooted shrub plant, growing in a former liquid waste disposal site (Solid Waste Management Unit [SWMU] 10-003[c]) at Los Alamos National Laboratory (LANL), Los Alamos, New Mexico. Surface soil samples were also collected from below (understory) and between (interspace) shrub canopies. Both chamisa plants growing over SWMU 10-003(c) contained significantly higher concentrations of {sup 90}Sr than a control plant--one plant, in particular, contained 3.35 x 10{sup 6} Bq kg{sup {minus}1} ash (9.05 x 10{sup 4} pCi g{sup {minus}1} ash) in top-growth material. Similarly, soil surface samples collected underneath and between plants contained {sup 90}Sr concentrations above background and LANL screening action levels (> 218 Bq kg{sup {minus}1} dry [5.90 pCi g{sup {minus}1} dry]); this probably occurred as a result of chamisa plant leaf fall contaminating the soil understory area followed by water and/or winds moving {sup 90}Sr to the soil interspace areas. Although some soil surface migration of {sup 90}Sr from SWMU 10-003(c) has occurred, the level of {sup 90}Sr in sediments collected downstream of SWMU 10-003(c) at the LANL boundary was still within regional (background) concentrations.

  12. Roles of uptake, biotransformation, and target site sensitivity in determining the differential toxicity of chlorpyrifos to second to fourth instar Chironomous riparius (Meigen)

    USGS Publications Warehouse

    Buchwalter, D.B.; Sandahl, J.F.; Jenkins, J.J.; Curtis, L.R.

    2004-01-01

    Early life stages of aquatic organisms tend to be more sensitive to various chemical contaminants than later life stages. This research attempted to identify the key biological factors that determined sensitivity differences among life stages of the aquatic insect Chironomous riparius. Specifically, second to fourth instar larvae were exposed in vivo to both low and high waterborne concentrations of chlorpyrifos to examine differences in accumulation rates, chlorpyrifos biotransformation, and overall sensitivity among instars. In vitro acetylcholinesterase (AChE) assays were performed with chlorpyrifos and the metabolite, chlorpyrifos-oxon, to investigate potential target site sensitivity differences among instars. Earlier instars accumulated chlorpyrifos more rapidly than later instars. There were no major differences among instars in the biotransformation rates of chlorpyrifos to the more polar metabolites, chlorpyrifos-oxon, and chlorpyridinol (TCP). Homogenate AChE activities from second to fourth instar larvae were refractory to chlorpyrifos, even at high concentrations. In contrast, homogenate AChE activities were responsive in a dose-dependent manner to chlorpyrifos-oxon. In general, it appeared that chlorpyrifos sensitivity differences among second to fourth instar C. riparius were largely determined by differences in uptake rates. In terms of AChE depression, fourth instar homogenates were more sensitive to chlorpyrifos and chlorpyrifos-oxon than earlier instars. However, basal AChE activity in fourth instar larvae was significantly higher than basal AChE activity in second to third instar larvae, which could potentially offset the apparent increased sensitivity to the oxon. ?? 2003 Elsevier B.V. All rights reserved.

  13. Effect of acute and chronic tramadol on [3H]-5-HT uptake in rat cortical synaptosomes

    PubMed Central

    Giusti, Pietro; Buriani, Alessandro; Cima, Lorenzo; Lipartiti, Maria

    1997-01-01

    Tramadol hydrochloride is a centrally acting opioid analgesic, the efficacy and potency of which is only five to ten times lower than that of morphine. Opioid, as well as non-opioid mechanisms, may participate in the analgesic activity of tramadol. [3H]-5-hydroxytryptamine (5-HT) uptake in rat isolated cortical synaptosomes was studied in the presence of tramadol, desipramine, fluoxetine, methadone and morphine. Methadone and tramadol inhibited synaptosomal [3H]-5-HT uptake with apparent Kis of 0.27±0.04 and 0.76±0.04 μM, respectively. Morphine essentially failed to inhibit [3H]-5-HT uptake (Ki 0.50±0.30 M). Methadone, morphine and tramadol were active in the hot plate test with ED50s of 3.5, 4.3 and 31 mg kg−1, respectively. At the highest tested dose (80 mg kg−1) tramadol produced only 77±5.3% of the maximal possible effect. When [3H]-5-HT uptake was examined in synaptosomes prepared from rats 30 min after a single dose of morphine, methadone or tramadol, only tramadol (31 mg kg−1, s.c., equal to the ED50 in the hot plate test) and methadone (35 mg kg−1, s.c., equal to the ED90 in the hot plate test) decreased uptake. Animals were chronically treated for 15 days with increasing doses of tramadol or methadone (5 to 40 mg kg−1 and 15 to 120 mg kg−1, s.c., respectively). Twenty-four hours after the last drug injection, a challenge dose of methadone (35 mg kg−1, s.c.) or tramadol (31 mg kg−1, s.c.) was administered. [3H]-5-HT uptake was not affected in synaptosomes prepared from rats chronically-treated with methadone, whereas chronic tramadol was still able to reduce this parameter by 42%. Rats chronically-treated with methadone showed a significant increase in [3H]-5-HT uptake (190%) 72 h after drug withdrawal. In contrast, [3H]-5-HT uptake in rats chronically-treated with tramadol (110%) did not differ significantly from control animals. These results further support the hypothesis that [3H]-5-HT uptake

  14. [C-11]{beta}CNT: A new monoamine uptake ligand for studying serotonin and dopamine transporter sites in the living brain with PET

    SciTech Connect

    Mulholland, G.K.; Zheng, Q.H.; Zhou, F.C.

    1996-05-01

    There is considerable interest in measuring serotonin (5HT) and dopamine (DA) function in the human brain. Altered levels of 5HT and DA are recognized in drug abuse, neurotoxicities, psychiatric disorders, and neurodegenerative conditions including Alzheimer`s and Parkinson`s disease. Several phenyltropane analogs of cocaine bind tightly to both DA and 5HT uptake proteins. We have made a new agent from this class called {beta}CNT, 2{beta}-carboxymethyl-3{beta}-(2-naphthyl)-tropane, the isosteric O-for-CH{sub 2} analog of a compound reported to have among the highest measured affinities for DA and 5HT transporters and studied its in vivo brain distributions in animals for the first time. Optically pure {beta}CNT was made from cocaine, and labeled at the O-methyl position by esterification of {beta}CNT-acid with [C-11]CH{sub 3}OTfl under conditions similar to Wilson`s. HPLC-purified (99+%) final products (15-50% eob yield from CO{sub 2}, 40 min synth) had specific activities 0.1-1.2 Ci/{mu}mol at the time of injection. Preliminary [C-11]{beta}{beta}CNT rodent distribution showed very high brain uptake (3% ID at 60 min) and localization (striat: fr cort: hypo: cer: blood, 11: 5: 4: 1: 06). {beta}CNT-PET studies in juvenile pigs (5-20 mCi, 20-35 kg) found rapid brain uptake, and prominent retention (85 min) in midbrain, anterior brainstem and striatum, followed by cortex and olfactory bulb. Paroxetine pretreatment (5HT uptake blocker, 2mg/kg), diminished retention in most brain areas; nomifensine (DA/NE uptake blocker, 6 mg/kg) reduced striatum selectively. Direct comparisons of [C-11]{beta}CNT with other PET transporter radioligands {beta}CFT, {beta}CIT, and {beta}CTT (RTI-32) in the same pig found {beta}CNT had highest overall brain uptake among the agents. These initial results suggest {beta}CNT has favorable properties for imaging both 5HT and DA transporters in vivo, and further evaluation of its potential as a human PET agent is warranted.

  15. Binding of [(3)H]lysergic acid diethylamide to serotonin 5-HT(2A) receptors and of [(3)H]paroxetine to serotonin uptake sites in platelets from healthy children, adolescents and adults.

    PubMed

    Sigurdh, J; Spigset, O; Allard, P; Mjörndal, T; Hägglöf, B

    1999-11-01

    Possible age effects on binding of [(3)H]lysergic acid diethylamide ([(3)H]LSD) to serotonin 5-HT(2A) receptors and of [(3)H]paroxetine to serotonin uptake sites were studied in platelets from healthy children (11-12 years of age), adolescents (16-17 years of age) and adults. Significant overall age effects were found both for the number of binding sites (B(max)) for [(3)H]LSD binding (p < 0.001), the affinity constant (K(d)) for [(3)H]LSD binding (p < 0.001), B(max) for [(3)H]paroxetine binding (p < 0.001) and K(d) for [(3)H] paroxetine binding (p = 0.006). In general, there was a decrease in B(max) with increasing age, which predominantly occurred between the ages 11-12 years and 16-17 years for the 5-HT(2A) receptor, and after 16-17 years of age for the serotonin uptake site. These developmental changes might have an impact on the effect of treatment with serotonergic drugs in children and adolescents. When the platelet serotonin variables investigated are employed in studies in children or adolescents, age matching or, alternatively, introduction of age control in the statistical analysis should be performed.

  16. Significant enhancement of gas uptake capacity and selectivity via the judicious increase of open metal sites and Lewis basic sites within two polyhedron-based metal-organic frameworks.

    PubMed

    Liu, Bing; Yao, Shuo; Shi, Chao; Li, Guanghua; Huo, Qisheng; Liu, Yunling

    2016-02-21

    Two new isomorphous polyhedron-based MOFs ( and ), with dual functionalities of OMSs and LBSs, have been synthesized by using the SBB strategy. By judiciously avoiding the DABCO axial ligand, possesses more OMSs than , and exhibits a significant enhancement of CO2 uptake capacity 210 versus 162 cm(3) g(-1) for at 273 K under 1 bar.

  17. Use of 2-(/sup 125/I)iodomelatonin to characterize melatonin binding sites in chicken retina

    SciTech Connect

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

    1987-06-01

    2-(/sup 125/I)Iodomelatonin binds with high affinity to a site possessing the pharmacological characteristics of a melatonin receptor in chicken retinal membranes. The specific binding of 2-(/sup 125/I)iodomelatonin is stable, saturable, and reversible. Saturation experiments indicated that 2-(/sup 125/I)iodomelatonin labeled a single class of sites with an affinity constant (Kd) of 434 +/- 56 pM and a total number of binding sites (Bmax) of 74.0 +/- 13.6 fmol/mg of protein. The affinity constant obtained from kinetic analysis was in close agreement with that obtained in saturation experiments. Competition experiments showed a monophasic reduction of 2-(/sup 125/I)iodomelatonin binding with a pharmacological order of indole amine affinities characteristic of a melatonin receptor: 2-iodomelatonin greater than 6-chloromelatonin greater than or equal to melatonin greater than or equal to 6,7-dichloro-2-methylmelatonin greater than 6-hydroxymelatonin greater than or equal to 6-methoxymelatonin much greater than N-acetyltryptamine greater than N-acetyl-5-hydroxytryptamine greater than 5-methoxytryptamine greater than 5-hydroxytryptamine (inactive). The affinities of these melatonin analogs in competing for 2-(/sup 125/I)iodomelatonin binding sites were correlated closely with their potencies for inhibition of the calcium-dependent release of (3H)dopamine from chicken and rabbit retinas, indicating association of the binding site with a functional response regulated by melatonin. The results indicate that 2-(/sup 125/I)iodomelatonin is a selective, high-affinity radioligand for the identification and characterization of melatonin receptor sites.

  18. Biaryl analogues of conformationally constrained tricyclic tropanes as potent and selective norepinephrine reuptake inhibitors: synthesis and evaluation of their uptake inhibition at monoamine transporter sites.

    PubMed

    Zhou, Jia; Zhang, Ao; Kläss, Thomas; Johnson, Kenneth M; Wang, Cheng Z; Ye, Yan Ping; Kozikowski, Alan P

    2003-05-01

    A series of novel conformationally constrained tricyclic tropane derivatives containing a biaryl moiety, (Z)-9-(biarylylmethylene)-7-azatricyclo[4.3.1.0(3,7)]decanes, were synthesized and evaluated for their ability to inhibit reuptake of dopamine (DA), serotonin (5-HT), and norepinephrine (NE) by the DA, 5-HT, and NE transporters. Most of the compounds containing a methoxycarbonyl substituent at C-10 exhibit moderate to high inhibitory activity at the NET but lower activity at the DAT and SERT. Among these new compounds, some potent, NET-selective ligands were identified. The p-methoxy derivative 11a has a K(i) value of 39 nM for uptake inhibition at the NET and moderate to high selectivity over the SERT (100-fold) and the DAT (20-fold). Compound 11f exhibits a remarkable potency (K(i) = 9.7 nM) at the NET and a 25-fold selectivity over both the SERT and the DAT. Analogue 23 containing a thiophene ring as a bioisosteric replacement of the phenyl ring Ar(1) displays a high activity (K(i) = 10.3 nM) for the NET and similar selectivity over the SERT (50-fold) and the DAT (37-fold). The selectivity profile of biaryl analogues differs from that of the monoaryl series, as most members of that series display excellent potency at and selectivity for the SERT (J. Med. Chem. 2002, 45, 1930). This finding suggests that the different shape and size of the lipophilic recognition pocket that encompasses the aryl ring(s) of these tropanes are major determinants of a ligand's transporter activity at either the NET or the SERT. Some of the compounds in this series may also be valuable in sorting out the contribution of the individual transporters to cocaine's reinforcing properties.

  19. An uptake of cationized ferritin by alveolar type I cells in airway-instilled goat lung: distribution of anionic sites on the epithelial surface.

    PubMed

    Atwal, O S; Viel, L; Minhas, K J

    1990-07-01

    The present study has investigated ultrastructural localization of anionic sites on the luminal surface of the alveolar epithelium of goat lung by direct airway instillation of cationized ferritin (CF) in the cranial lobe of the right lung through a bronchoscope. The cationic probe decorated preferentially the luminal plasmalemmal vesicles and plasmalemma proper of alveolar type I cell. This indicated the presence of highly charged anionic microdomains at these binding sites. The ligand was internalized in the free plasmalemmal vesicles of alveolar type I cell within 2 min. Heavy decoration of vesicles at 5 min of perfusion indicated that the amount of CF internalization increased with its concentration in the alveoli. It is suggested that exposure of alveolar surface to several gases of ruminal-origin induces changes in the surface charge of luminal plasmalemma of alveolar type I cells. The significance of these anionic plasmalemmal sites is discussed in relation to the adjustment of osmotic pressure gradient across the alveolar-capillary membrane of the ruminant lung.

  20. An uptake of cationized ferritin by alveolar type I cells in airway-instilled goat lung: distribution of anionic sites on the epithelial surface.

    PubMed

    Atwal, O S; Viel, L; Minhas, K J

    1990-07-01

    The present study has investigated ultrastructural localization of anionic sites on the luminal surface of the alveolar epithelium of goat lung by direct airway instillation of cationized ferritin (CF) in the cranial lobe of the right lung through a bronchoscope. The cationic probe decorated preferentially the luminal plasmalemmal vesicles and plasmalemma proper of alveolar type I cell. This indicated the presence of highly charged anionic microdomains at these binding sites. The ligand was internalized in the free plasmalemmal vesicles of alveolar type I cell within 2 min. Heavy decoration of vesicles at 5 min of perfusion indicated that the amount of CF internalization increased with its concentration in the alveoli. It is suggested that exposure of alveolar surface to several gases of ruminal-origin induces changes in the surface charge of luminal plasmalemma of alveolar type I cells. The significance of these anionic plasmalemmal sites is discussed in relation to the adjustment of osmotic pressure gradient across the alveolar-capillary membrane of the ruminant lung. PMID:2390765

  1. Rates and Determinants of Uptake and Use of an Internet Physical Activity and Weight Management Program in Office and Manufacturing Work Sites in England: Cohort Study

    PubMed Central

    Hurling, Robert; Bataveljic, Ogi; Fairley, Bruce W; Hurst, Tina L; Murray, Peter; Rennie, Kirsten L; Tomkins, Chris E; Finn, Anne; Cobain, Mark R; Pearson, Dympna A; Foreyt, John P

    2008-01-01

    Background Internet-based physical activity (PA) and weight management programs have the potential to improve employees’ health in large occupational health settings. To be successful, the program must engage a wide range of employees, especially those at risk of weight gain or ill health. Objective The aim of the study was to assess the use and nonuse (user attrition) of a Web-based and monitoring device–based PA and weight management program in a range of employees and to determine if engagement with the program was related to the employees’ baseline characteristics or measured outcomes. Methods Longitudinal observational study of a cohort of employees having access to the MiLife Web-based automated behavior change system. Employees were recruited from manufacturing and office sites in the North West and the South of England. Baseline health data were collected, and participants were given devices to monitor their weight and PA via data upload to the website. Website use, PA, and weight data were collected throughout the 12-week program. Results Overall, 12% of employees at the four sites (265/2302) agreed to participate in the program, with 130 men (49%) and 135 women (51%), and of these, 233 went on to start the program. During the program, the dropout rate was 5% (11/233). Of the remaining 222 Web program users, 173 (78%) were using the program at the end of the 12 weeks, with 69% (153/222) continuing after this period. Engagement with the program varied by site but was not significantly different between the office and factory sites. During the first 2 weeks, participants used the website, on average, 6 times per week, suggesting an initial learning period after which the frequency of website log-in was typically 2 visits per week and 7 minutes per visit. Employees who uploaded weight data had a significant reduction in weight (−2.6 kg, SD 3.2, P< .001). The reduction in weight was largest for employees using the program’s weight loss mode (−3

  2. Application of ground bone and sheep manure on soils from two contaminated sites and influence on oat growth, uranium and radium uptake and translocation

    NASA Astrophysics Data System (ADS)

    Abreu, M. M.; Pacheco, A.; Santos, E.; Magalhães, M. C. F.

    2012-04-01

    Past radium and uranium exploitation and processing in Urgeiriça mine and radium processing in Barracão (centre-north of Portugal) led to soils and waters contamination. Most of the soils, located in rural areas, are cultivated for vegetables, fruit trees, and/or pasturage, and the waters used for soils irrigation. The objective of this work was to evaluate the capacity of organic amendments and hydroxiapatite to reduce the soil available fraction of Utotal and 226Ra in soils of two areas after four months of incubation. Influence on oat growth, uranium and radium uptake and translocation was also studied. Pot experiments, under controlled conditions, were undertaken during four months of incubation at 70% of the soil water-holding capacity. Urgeiriça (Urg) and Barracão (Brc) soils containing large concentrations of Utotal (635 and 189 mg/kg, respectively), and 226Ra (2310 and 1770 Bq/kg, respectively) were used. The available fraction of these elements, extracted with ammonium acetate, corresponds to: 90 and 20% of total concentration of uranium and radium, respectively, for Urgeiriça soil, and 19 and 43% of total concentration of uranium and radium, respectively, for Barracão soil. Fine ground bone (FB), sheep manure (OM), and vermicompost (V) single or mixtures were used as amendments. Control (soil) and treatments were made in triplicate: (T1) soil+96 g FB/kg of soil; (T2) soil+168 g OM/kg of soil; (T3) soil+168 g OM/kg of soil+96 g FB/kg of soil; (T4) soil+168 g V/kg of soil. After incubation, soil subsamples were analysed for pH, electric conductivity (EC), and available fractions of Utotal and 226Ra. The remaining soils were used for oat (Avena sativa L.) cultivation. Soils had pH 5.15 (Urg) and 6.04 (Brc), and EC 57.3 µS/cm (Urg) and 36.3 µS/cm (Brc). After incubation soil pH increased to a maximum of 6.82 (Urg) and 7.10 (Brc) in amended samples, and EC showed a large increase (15-19 times) when compared to the control. A decrease of the available

  3. Binding of [3H]paroxetine to serotonin uptake sites and of [3H]lysergic acid diethylamide to 5-HT2A receptors in platelets from women with premenstrual dysphoric disorder during gonadotropin releasing hormone treatment.

    PubMed

    Bixo, M; Allard, P; Bäckström, T; Mjörndal, T; Nyberg, S; Spigset, O; Sundström-Poromaa, I

    2001-08-01

    Changes in serotonergic parameters have been reported in psychiatric conditions such as depression but also in the premenstrual dysphoric disorder (PMDD). In addition, hormonal effects on serotonergic activity have been established. In the present study, binding of [3H]paroxetine to platelet serotonin uptake sites and binding of [3H]lysergic acid diethylamide ([3H]LSD) to platelet serotonin (5-HT)2A receptors were studied in patients with PMDD treated with a low dose of a gonadotropin releasing hormone (GnRH) agonist (buserelin) or placebo and compared to controls. The PMDD patients were relieved of premenstrual symptoms like depression and irritability during buserelin treatment. The number of [3H]paroxetine binding sites (Bmax) were significantly higher in the follicular phase in untreated PMDD patients compared to controls. When treated with buserelin the difference disappeared. No differences in [3H]LSD binding between the three groups were shown. The present study demonstrated altered platelet [3H]paroxetine binding characteristics in women with PMDD compared to controls. Furthermore, [3H]paroxetine binding was affected by PMDD treatment with a low dose of buserelin. The results are consistent with the hypothesis that changes in serotonergic transmission could be a trait in the premenstrual dysphoric disorder.

  4. Potential Moderating Effects of Selenium on Mercury Uptake and Selenium:Mercury Molar Ratios in Fish From Oak Ridge and Savannah River Site - 12086

    SciTech Connect

    Burger, Joanna; Gochfeld, Michael; Donio, Mark; Jeitner, Christian; Pittfield, Taryn

    2012-07-01

    Mercury contamination is an important remediation issue at the U.S. Department of Energy's (DOE) Oak Ridge Reservation and to a lesser extent at other DOE sites because of the hazard it presents, potential consequences to humans and eco-receptors, and completed pathways, to offsite receptors. Recent work has emphasized that selenium might ameliorate the toxicity of mercury, and we examine the selenium:mercury (Se:Hg) molar ratios in fish from Oak Ridge, and compare them to Se:Hg molar ratios in fish from the Savannah River. Selenium/mercury molar ratios varied considerably among and within fish species. There was considerable variation in the molar ratios for individual fish (as opposed to mean ratios by species) for freshwater fish from both sites. The inter-individual variation in molar ratios indicates that such that the molar ratios of mean Se and Hg concentrations may not be representative. Even for fish species with relatively low mercury levels, some individual fish have molar ratios less than unity, the value sometime thought to be protective. Selenium levels varied narrowly regardless of fish size, consistent with homeostatic regulation of this essential trace element. The data indicate that considerable attention will need to be directed toward variations and variances, as well as the mechanisms of the interaction of selenium and mercury, before risk assessment and risk management policies can use this information to manage mercury pollution and risk. Even so, if there are high levels of selenium in the fish from Poplar Creek on Oak Ridge, then the potential exists for some amelioration of adverse health effects, on the fish themselves, predators that eat them, and people who consume them. This work will aid DOE because it will allow managers and scientists to understand another aspect that affects fate and transport of mercury, as well as the potential effects of methylmercury in fish for human and ecological receptors. The variability within fish

  5. 5-hydroxytryptamine and Lyme disease. Opportunity for a novel therapy to reduce the cerebellar tremor?

    PubMed

    Maximov, G K; Maximov, K G; Chokoeva, A A; Lotti, T; Wollina, U; Patterson, J W; Guarneri, C; Tana, C; Fioranelli, M; Roccia, M G; Kanazawa, N; Tchernev, G

    2016-01-01

    Lyme boreliosis is caused by the spirochete Borrelia burdorferi, which is transmitted by ticks. A 59 year-old woman developed pyrexia, strong headaches, ataxia, dysarthria and tremor of the limbs after a tick bite. She was unable to work and eat on her own. She was hospitalized three times and diagnosed with cerebellar intention tremor, cerebellar ataxia, dysarthria, bilateral horizontal gaze paralysis and a central lesion of the left facial nerve. There were no pyramidal, sensory or psychiatric disturbances. The brain MRI showed multifocal leucoencephalopathy with many hyperintense areas in both hemispheres, as well as in the left superior pedunculus cerebellaris. Diagnosis was confirmed by serologic examination. Treatment with cephtriaxone, doxycycline, methylprednisolone, cephixime and ciprofloxacine was administered without effect on the tremor, ataxia and horizontal gaze paralysis. Treatment was then administered with 5-hydroxytriptamine (5-HT) in increased doses. The result of the three-month treatment with 5-HT was a gradual diminution of the tremor and the ataxia and an increase in the ability to eat, walk and work independently. PMID:27373127

  6. Action of 5-hydroxytryptamine on intestinal ion transport in the rat.

    PubMed Central

    Hardcastle, J; Hardcastle, P T; Redfern, J S

    1981-01-01

    1. 5-HT increased the electrical activity of rat jejunum both in vivo and in vitro. The increased potential difference and short-circuit current resulted from a stimulation of electrogenic chloride secretion. NaCl absorption may also have been inhibited. 2. 5-HT did not alter cyclic AMP levels in isolated enterocytes. 3. The 5-HT response in vivo was unaffected by atropine, cyproheptadine, propranolol and hexamethonium. Phenoxybenzamine reduced the maximum response without affecting the dose required to produce a 50% maximum response. Methysergide, at a dose of 40 mg/kg, had a similar effect while a lower dose of 2 mg/kg produced no change. Mianserin competitively antagonized the response to 5-HT, a dose of 2 mg/kg producing a fourfold increase in the amount of 5-HT required to produce a 50% maximum response. 4. Acetylcholine and 5-HT seem to act independently in inducing intestinal secretion since atropine did not block the response to 5-HT and Mianserin did not alter the response to acetylcholine. 5. Experiments in which the intestinal villi or crypts were subjected to preferential damage suggested that 5-HT primarily produced its response at the crypt cell level. PMID:6275078

  7. 5-Hydroxytryptamine type 7 receptor neuroprotection against NMDA-induced excitotoxicity is PDGFβ receptor dependent.

    PubMed

    Vasefi, Maryam S; Kruk, Jeff S; Heikkila, John J; Beazely, Michael A

    2013-04-01

    The serotonin (5-HT) type 7 receptor is expressed throughout the CNS including the hippocampus. Long-term (2-24 h) activation of 5-HT7 receptors regulates growth factor receptor expression, including the expression of platelet-derived growth factor (PDGF) β receptors. Direct activation of PDGFβ receptors in primary hippocampal and cortical neurons inhibits NMDA receptor activity and attenuates NMDA receptor-induced neurotoxicity. Our objective was to investigate whether the 5-HT7 receptor-induced increase in PDGFβ receptor expression would be similarly neuroprotective. We demonstrate that 5-HT7 receptor agonist treatment in primary hippocampal neurons also increases the expression of phospholipase C (PLC) γ, a downstream effector of PDGFβ receptors associated with the inhibition of NMDA receptor activity. To determine if the up-regulation of PDGFβ receptors is neuroprotective, primary hippocampal neurons were incubated with the 5-HT7 receptor agonist, LP 12, for 24 h. Indeed, LP 12 treatment prevented NMDA-induced neurotoxicity and this effect was dependent on PDGFβ receptor kinase activity. Treatment of primary neurons with LP 12 also differentially altered NMDA receptor subunit expression, reducing the expression of NR1 and NR2B, but not NR2A. These findings demonstrate the potential for providing growth factor receptor-dependent neuroprotective effects using small-molecule ligands of G protein-coupled receptors.

  8. Cystathionine γ lyase-hydrogen sulfide increases peroxisome proliferator-activated receptor γ activity by sulfhydration at C139 site thereby promoting glucose uptake and lipid storage in adipocytes.

    PubMed

    Cai, Junyan; Shi, Xiaoqin; Wang, Huamin; Fan, Jinghui; Feng, Yongliang; Lin, Xianjuan; Yang, Jichun; Cui, Qinghua; Tang, Chaoshu; Xu, Guoheng; Geng, Bin

    2016-05-01

    Adipocytes express the cystathionine γ lyase (CSE)-hydrogen sulfide (H2S) system. CSE-H2S promotes adipogenesis but ameliorates adipocyte insulin resistance. We investigated the mechanism of how CSE-H2S induces these paradoxical effects. First, we confirmed that an H2S donor or CSE overexpression promoted adipocyte differentiation. Second, we found that H2S donor inhibited but CSE inhibition increased phosphodiesterase (PDE) activity. H2S replacing isobutylmethylxanthine in the differentiation program induced adipocyte differentiation in part. Inhibiting PDE activity by H2S induced peroxisome proliferator activated receptor γ (PPARγ) protein and mRNA expression. Of note, H2S directly sulfhydrated PPARγ protein. Sulfhydrated PPARγ increased its nuclear accumulation, DNA binding activity and adipogenesis gene expression, thereby increasing glucose uptake and lipid storage, which were blocked by the desulfhydration reagent DTT. H2S induced PPARγ sulfhydration, which was blocked by mutation of the C139 site of PPARγ. In mice fed a high-fat diet (HFD) for 4 weeks, the CSE inhibitor decreased but H2S donor increased adipocyte numbers. In obese mice fed an HFD for 13 weeks, H2S treatment increased PPARγ sulfhydration in adipose tissues and attenuated insulin resistance but did not increase obesity. In conclusion, CSE-H2S increased PPARγ activity by direct sulfhydration at the C139 site, thereby changing glucose into triglyceride storage in adipocytes. CSE-H2S-mediated PPARγ activation might be a new therapeutic target for diabetes associated with obesity. PMID:26946260

  9. Cystathionine γ lyase-hydrogen sulfide increases peroxisome proliferator-activated receptor γ activity by sulfhydration at C139 site thereby promoting glucose uptake and lipid storage in adipocytes.

    PubMed

    Cai, Junyan; Shi, Xiaoqin; Wang, Huamin; Fan, Jinghui; Feng, Yongliang; Lin, Xianjuan; Yang, Jichun; Cui, Qinghua; Tang, Chaoshu; Xu, Guoheng; Geng, Bin

    2016-05-01

    Adipocytes express the cystathionine γ lyase (CSE)-hydrogen sulfide (H2S) system. CSE-H2S promotes adipogenesis but ameliorates adipocyte insulin resistance. We investigated the mechanism of how CSE-H2S induces these paradoxical effects. First, we confirmed that an H2S donor or CSE overexpression promoted adipocyte differentiation. Second, we found that H2S donor inhibited but CSE inhibition increased phosphodiesterase (PDE) activity. H2S replacing isobutylmethylxanthine in the differentiation program induced adipocyte differentiation in part. Inhibiting PDE activity by H2S induced peroxisome proliferator activated receptor γ (PPARγ) protein and mRNA expression. Of note, H2S directly sulfhydrated PPARγ protein. Sulfhydrated PPARγ increased its nuclear accumulation, DNA binding activity and adipogenesis gene expression, thereby increasing glucose uptake and lipid storage, which were blocked by the desulfhydration reagent DTT. H2S induced PPARγ sulfhydration, which was blocked by mutation of the C139 site of PPARγ. In mice fed a high-fat diet (HFD) for 4 weeks, the CSE inhibitor decreased but H2S donor increased adipocyte numbers. In obese mice fed an HFD for 13 weeks, H2S treatment increased PPARγ sulfhydration in adipose tissues and attenuated insulin resistance but did not increase obesity. In conclusion, CSE-H2S increased PPARγ activity by direct sulfhydration at the C139 site, thereby changing glucose into triglyceride storage in adipocytes. CSE-H2S-mediated PPARγ activation might be a new therapeutic target for diabetes associated with obesity.

  10. 5-HT1B Autoreceptors limit the effects of selective serotonin re-uptake inhibitors in mouse hippocampus and frontal cortex.

    PubMed

    Malagié, I; Trillat, A C; Bourin, M; Jacquot, C; Hen, R; Gardier, A M

    2001-02-01

    We used knockout mice and receptor antagonist strategies to investigate the contribution of the serotonin (5-hydroxytryptamine, 5-HT) 1B receptor subtype in mediating the effects of selective serotonin re-uptake inhibitors (SSRIs). Using in vivo intracerebral microdialysis in awake mice, we show that a single systemic administration of paroxetine (1 or 5 mg/kg, i.p.) increased extracellular serotonin levels [5-HT]ext in the ventral hippocampus and frontal cortex of wild-type and mutant mice. However, in the ventral hippocampus, paroxetine at the two doses studied induced a larger increase in [5-HT]ext in knockout than in wild-type mice. In the frontal cortex, the effect of paroxetine was larger in mutants than in wild-type mice at the 1 mg/kg, but not at 5 mg/kg. In addition, either the absence of the 5-HT1B receptor or its blockade with the mixed 5-HT1B/1D receptor antagonist, GR 127935, potentiated the effect of a single administration of paroxetine on extracellular 5-HT levels more in the ventral hippocampus than in the frontal cortex. These data suggest that 5-HT1B autoreceptors limit the effects of SSRIs on dialysate 5-HT levels at serotonergic nerve terminals.

  11. Iodine 125-lysergic acid diethylamide binds to a novel serotonergic site on rat choroid plexus epithelial cells

    SciTech Connect

    Yagaloff, K.A.; Hartig, P.R.

    1985-12-01

    /sup 125/I-Lysergic acid diethylamide (/sup 125/I-LSD) binds with high affinity to serotonergic sites on rat choroid plexus. These sites were localized to choroid plexus epithelial cells by use of a novel high resolution stripping film technique for light microscopic autoradiography. In membrane preparations from rat choroid plexus, the serotonergic site density was 3100 fmol/mg of protein, which is 10-fold higher than the density of any other serotonergic site in brain homogenates. The choroid plexus site exhibits a novel pharmacology that does not match the properties of 5-hydroxytryptamine-1a (5-HT1a), 5-HT1b, or 5-HT2 serotonergic sites. /sup 125/I-LSD binding to the choroid plexus site is potently inhibited by mianserin, serotonin, and (+)-LSD. Other serotonergic, dopaminergic, and adrenergic agonists and antagonists exhibit moderate to weak affinities for this site. The rat choroid plexus /sup 125/I-LSD binding site appears to represent a new type of serotonergic site which is located on non-neuronal cells in this tissue.

  12. Further studies on conformationally constrained tricyclic tropane analogues and their uptake inhibition at monoamine transporter sites: synthesis of (Z)-9-(substituted arylmethylene)-7-azatricyclo[4.3.1.0(3,7)]decanes as a novel class of serotonin transporter inhibitors.

    PubMed

    Zhang, Ao; Zhou, Guochun; Hoepping, Alexander; Mukhopadhyaya, Jayanta; Johnson, Kenneth M; Zhang, Mei; Kozikowski, Alan P

    2002-04-25

    A novel series of conformationally constrained tricyclic tropane analogues, (Z)-9-(substituted arylmethylene)-7-azatricyclo[4.3.1.0(3,7)]decanes, were prepared, and their abilities to inhibit high-affinity uptake of dopamine (DA), serotonin (5-HT), and norepinephrine (NE) into rat brain nerve endings (synaptosomes) were evaluated. First, a systematic screening of a variety of different substituents on the phenyl ring indicated that the substitution pattern plays an important role in the monoamine transporter activity. Most compounds in this series possessed a very low activity at the DA transporter (DAT) but a good to excellent affinity for the 5-HT transporter (SERT). In the case of para-substituted phenyl analogues, the electronic character of the substituent did not affect uptake inhibition as dramatically as observed in some benztropine analogues. Among these compounds, the 4-bromophenyl and 4-isopropylphenyl analogues 8d and 8j exhibited the highest potency at the SERT with a K(i) value of 10 nM. In the 3,4-disubstituted phenyl series, even more potent and highly selective compounds were discovered. Compound 8o has a K(i) value of 2.3 nM for uptake inhibition at the SERT, a DAT/SERT uptake ratio of 2360, and a NET/SERT uptake ratio of 200. Compound 8p exhibited a K(i) value of 1.8 nM for uptake inhibition at the SERT, a DAT/SERT uptake ratio of 1740, and a NET/SERT uptake ratio of 151. These compounds are 3-4-fold more potent than the antidepressant medication fluoxetine, and the selectivities for SERT over DAT and NET are also better than those of fluoxetine. Second, a variety of functional modifications on the ester moiety were investigated. Substitution by other esters or amides as well as alkenes did not increase potency, while most of the acetates or benzoates (16-21, 23, and 24) and the ketone 28 exhibited significantly improved activity. A good hydrogen-bonding ability of the substituent is believed to be required for high activity. The most potent and

  13. Mitochondrial calcium uptake.

    PubMed

    Williams, George S B; Boyman, Liron; Chikando, Aristide C; Khairallah, Ramzi J; Lederer, W J

    2013-06-25

    Calcium (Ca(2+)) uptake into the mitochondrial matrix is critically important to cellular function. As a regulator of matrix Ca(2+) levels, this flux influences energy production and can initiate cell death. If large, this flux could potentially alter intracellular Ca(2+) ([Ca(2+)]i) signals. Despite years of study, fundamental disagreements on the extent and speed of mitochondrial Ca(2+) uptake still exist. Here, we review and quantitatively analyze mitochondrial Ca(2+) uptake fluxes from different tissues and interpret the results with respect to the recently proposed mitochondrial Ca(2+) uniporter (MCU) candidate. This quantitative analysis yields four clear results: (i) under physiological conditions, Ca(2+) influx into the mitochondria via the MCU is small relative to other cytosolic Ca(2+) extrusion pathways; (ii) single MCU conductance is ∼6-7 pS (105 mM [Ca(2+)]), and MCU flux appears to be modulated by [Ca(2+)]i, suggesting Ca(2+) regulation of MCU open probability (P(O)); (iii) in the heart, two features are clear: the number of MCU channels per mitochondrion can be calculated, and MCU probability is low under normal conditions; and (iv) in skeletal muscle and liver cells, uptake per mitochondrion varies in magnitude but total uptake per cell still appears to be modest. Based on our analysis of available quantitative data, we conclude that although Ca(2+) critically regulates mitochondrial function, the mitochondria do not act as a significant dynamic buffer of cytosolic Ca(2+) under physiological conditions. Nevertheless, with prolonged (superphysiological) elevations of [Ca(2+)]i, mitochondrial Ca(2+) uptake can increase 10- to 1,000-fold and begin to shape [Ca(2+)]i dynamics.

  14. Specific [(3)H]tryptophan binding sites in rat brain.

    PubMed

    Wong, P T; Lee, H S; Tan, C H; Teo, W L

    1989-01-01

    [(3)H]Tryptophan binds to a single population of sites in the rat cortical synaptosomal membranes. The binding is reversible and follows the law of mass action. By saturation studies using increasing concentration of [(3)H]tryptophan with decreasing specific radioactivity, the apparent K(d) obtained was approx. 0.8 ?M and the B(max) 110 pmol/mg protein. However, the IC(50) obtained for unlabelled tryptophan in displacing [(3)H]tryptophan binding (3.5 nM) was 0.26 ?M. All six naturally occurring aromatic amino acids studied displaced [(3)H]tryptophan binding with tryptophan and phenylalanine showing higher apparent affinity than histidine, tyrosine, dihydroxyphenylalanine and 5-hydroxytryptophan. These binding sites are proteins in nature as they are sensitive to trypsin and ?-chymotrypsin. It is observed that about 37% of the sites seem to be protected from the proteolytic enzymes by the membrane structure. Furthermore, they are extremely sensitive to phospholipase A(2) presumably because altered membrane phospholipids conduce a conformational change in the binding protein. A considerable degree of stereospecificity was demonstrated with the affinity for l-tryptophan about 90 times higher than that for d-tryptophan. The affinity for l-phenylalanine was 8 times higher than that for d-phenylalanine. Ligand specificity for the aromatic amino acids is remarkable as hydrocinnamic acid, 2-phenylethylamine, 5-hydroxytryptamine, histamine, dopamine, ?-aminobutyric acid, glutamic acid and taurine did not displace [(3)H]tryptophan binding. Therefore, these sites are termed aromatic amino acid binding sites (AABS). Whether or not AABS are involved in neuromodulation at the synapse awaits clarification. If so, the endogenous ligand for the AABS may well be tryptophan.

  15. Proton uptake associated with the reduction of the primary quinone Q(A) influences the binding site of the secondary quinone Q(B) in Rhodopseudomonas viridis photosynthetic reaction centers.

    PubMed

    Zachariae, U; Lancaster, C R

    2001-06-01

    Previously, two binding sites for the secondary quinone Q(B) in the photosynthetic reaction center (RC) from Rhodopseudomonas viridis were identified by X-ray crystallography, a 'proximal' binding site close to the non-heme iron, and a 'distal' site, displaced by 4.2 A along the path of the isoprenoid tail [C.R.D. Lancaster and H. Michel, Structure 5 (1997) 1339-1359]. The quinone ring planes in the two sites differ by roughly a 180 degrees rotation around the isoprenoid tail. Here we present molecular dynamics simulations, which support the theory of a spontaneous transfer of Q(B) between the distal site and the proximal site. In contrast to earlier computational studies on RCs, the molecular dynamics simulations of Q(B) migration resulted in a proximal Q(B) binding pattern identical to that of the crystallographic findings. Also, we demonstrate that the preference towards the proximal Q(B) location is not necessarily attributed to reduction of Q(B) to the semiquinone, but already to the preceding reduction of the primary quinone Q(A) and resulting protonation changes in the protein. Energy mapping of the Q(B) binding pocket indicates that the quinone ring rotation required for completion of the transfer between the two sites is improbable at the distal or proximal binding sites due to high potential barriers, but may be possible at a newly identified position near the distal binding site.

  16. Putrescine uptake in saintpaulia petals.

    PubMed

    Bagni, N; Pistocchi, R

    1985-02-01

    Putrescine uptake and the kinetics of this uptake were studied in petals of Saintpaulia ionantha Wendl. Uptake experiments of [(3)H] or [(14)C] putrescine were done on single petals at room temperature at various pH values. The results show that putrescine uptake occurs against a concentration gradient at low external putrescine concentration (0.5-100 micromolar) and follows a concentration gradient at higher external putrescine concentrations (100 micromolar to 100 millimolar). 2,4-Dinitrophenol and carbonylcyanide-m-chlorophenylhydrazone, two uncouplers, had no effect on putrescine uptake. Uptake rates were constant for 2 hours, reaching a maximum after 3 to 4 hours. Putrescine uptake depended markedly on the external pH and two maxima were observed: at low external concentrations of putrescine, the optimum was at pH 5 to 5.5; at higher concentrations the optimum was at pH 8. PMID:16664065

  17. Coupling nutrient uptake and energy flow in headwater streams

    SciTech Connect

    Mulholland, Patrick J; Fellows, Christine; Valett, H. Maurice; Dahm, Cliff; Thomas, Steve

    2006-08-01

    Nutrient cycling and energy flow in ecosystems are tightly linked through the metabolic processes of organisms. Greater uptake of inorganic nutrients is expected to be associated with higher rates of metabolism [gross primary production (GPP) and respiration (R)], due to assimilatory demand of both autotrophs and heterotrophs. However, relationships between uptake and metabolism should vary with the relative contribution of autochthonous and allochthonous sources of organic matter. To investigate the relationship between metabolism and nutrient uptake, we used whole-stream and benthic chamber methods to measure rates of nitrate-nitrogen (NO{sub 3}-N) uptake and metabolism in four headwater streams chosen to span a range of light availability and therefore differing rates of GPP and contributions of autochthonous carbon. We coupled whole-stream metabolism with measures of NO{sub 3}-N uptake conducted repeatedly over the same stream reach during both day and night, as well as incubating benthic sediments under both light and dark conditions. NO{sub 3}-N uptake was generally greater in daylight compared to dark conditions, and although day-night differences in whole-stream uptake were not significant, light-dark differences in benthic chambers were significant at three of the four sites. Estimates of N demand indicated that assimilation by photoautotrophs could account for the majority of NO{sub 3}-N uptake at the two sites with relatively open canopies. Contrary to expectations, photoautotrophs contributed substantially to NO{sub 3}-N uptake even at the two closed-canopy sites, which had low values of GPP/R and relied heavily on allochthonous carbon to fuel R.

  18. Endocytotic uptake of nutrients in carnivorous plants.

    PubMed

    Adlassnig, Wolfram; Koller-Peroutka, Marianne; Bauer, Sonja; Koshkin, Edith; Lendl, Thomas; Lichtscheidl, Irene K

    2012-07-01

    Carnivorous plants trap, digest and absorb animals in order to supplement their mineral nutrition. Nutrients absorbed by the plant include different nitrogen species, phosphate, potassium, trace elements and small organic compounds. Uptake is usually thought to be performed via specific channels, but this study provides evidence that endocytosis is involved as well. Traps of the carnivorous plants Nepenthes coccinea, Nepenthes ventrata, Cephalotus follicularis, Drosophyllum lusitanicum, Drosera capensis, Dionaea muscipula, Aldrovanda vesiculosa, Genlisea violacea × lobata, Sarracenia psittacina and Sarracenia purpurea were stained with methylene blue in order to identify possible sites of uptake. The permeable parts of the traps were incubated with fluorescein isothiocyanate labelled bovine serum albumin (FITC-BSA) and other fluorescent endocytosis markers, combined with the soluble protein BSA or respiratory inhibitors. Uptake was studied by confocal microscopy. In Nepenthes, small fluorescent vesicles became visible 1 h after incubation with FITC-BSA. These vesicles fused to larger compartments within 30 h. A similar behaviour was found in the related genera Drosera, Dionaea, Aldrovanda and Drosophyllum but also in Cephalotus with glands of different evolutionary origin. In Genlisea and Sarracenia, no evidence for endocytosis was found. We propose that in many carnivorous plants, nutrient uptake by carriers is supplemented by endocytosis, which enables absorption and intracellular digestion of whole proteins. The advantage for the plant of reducing secretion of enzymes for extracellular digestion is evident.

  19. Endocytotic uptake of nutrients in carnivorous plants.

    PubMed

    Adlassnig, Wolfram; Koller-Peroutka, Marianne; Bauer, Sonja; Koshkin, Edith; Lendl, Thomas; Lichtscheidl, Irene K

    2012-07-01

    Carnivorous plants trap, digest and absorb animals in order to supplement their mineral nutrition. Nutrients absorbed by the plant include different nitrogen species, phosphate, potassium, trace elements and small organic compounds. Uptake is usually thought to be performed via specific channels, but this study provides evidence that endocytosis is involved as well. Traps of the carnivorous plants Nepenthes coccinea, Nepenthes ventrata, Cephalotus follicularis, Drosophyllum lusitanicum, Drosera capensis, Dionaea muscipula, Aldrovanda vesiculosa, Genlisea violacea × lobata, Sarracenia psittacina and Sarracenia purpurea were stained with methylene blue in order to identify possible sites of uptake. The permeable parts of the traps were incubated with fluorescein isothiocyanate labelled bovine serum albumin (FITC-BSA) and other fluorescent endocytosis markers, combined with the soluble protein BSA or respiratory inhibitors. Uptake was studied by confocal microscopy. In Nepenthes, small fluorescent vesicles became visible 1 h after incubation with FITC-BSA. These vesicles fused to larger compartments within 30 h. A similar behaviour was found in the related genera Drosera, Dionaea, Aldrovanda and Drosophyllum but also in Cephalotus with glands of different evolutionary origin. In Genlisea and Sarracenia, no evidence for endocytosis was found. We propose that in many carnivorous plants, nutrient uptake by carriers is supplemented by endocytosis, which enables absorption and intracellular digestion of whole proteins. The advantage for the plant of reducing secretion of enzymes for extracellular digestion is evident. PMID:22417315

  20. Phospholipase A2 and 3H-hemicholinium-3 binding sites in rat brain: A potential second-messenger role for fatty acids in the regulation of high-affinity choline uptake

    SciTech Connect

    Saltarelli, M.D.; Yamada, K.; Coyle, J.T. )

    1990-01-01

    The involvement of phospholipase A2 (PLA2) and fatty acid release in the regulation of sodium-dependent high-affinity choline uptake in rat brain was assessed in vitro through the use of the specific binding of 3H-hemicholinium-3 (3H-HCh-3). Addition of arachidonic acid and other unsaturated fatty acids to rat striatal membranes in vitro resulted in a dose-dependent, temperature-independent activation of 3H-HCh-3 binding. Scatchard analysis revealed that these changes in binding result from a 2-fold increase in the affinity and capacity of 3H-HCh-3 binding. Saturated fatty acids, lysophospholipids, and phospholipids did not affect specific 3H-HCh-3 binding. Addition of defatted BSA to membranes, which had been treated previously with arachidonic acid, completely reversed the increase in specific 3H-HCh-3 binding. However, several inhibitors of fatty acid metabolism, including nordihydroguaiaretic acid, indomethacin, catalase, and superoxide dismutase, did not alter arachidonic acid-induced changes in 3H-HCh-3 binding, suggesting that unsaturated fatty acids, and not their metabolites, are directly responsible for the observed activation of specific 3H-HCh-3 binding. Additionally, unsaturated fatty acids dose-dependently inhibited high-affinity 3H-choline uptake in rat striatal synaptosomes, apparently due to the disruption of synaptosomal integrity. The phospholipase A2 inhibitors quinacrine hydrochloride, trifluoperazine, and 4-bromophenacylbromide dose-dependently inhibited potassium depolarization-induced activation of specific 3H-HCh-3 binding in slices of rat brain in vitro. Similarly, both quinacrine and trifluoperazine inhibited the metabolism of phospholipids and the release of fatty acids evoked by either elevated KCl or calcium ionophore A23187.

  1. 5-Hydroxytryptamine 2A receptor signaling cascade modulates adiponectin and plasminogen activator inhibitor 1 expression in adipose tissue.

    PubMed

    Uchida-Kitajima, Shoko; Yamauchi, Toshimasa; Takashina, Youko; Okada-Iwabu, Miki; Iwabu, Masato; Ueki, Kohjiro; Kadowaki, Takashi

    2008-09-01

    Knowledge of the regulatory factors associated with down-regulation of adiponectin gene expression and up-regulation of PAI-1 gene expression is crucial to understand the pathophysiological basis of obesity and metabolic diseases, and could establish new treatment strategies for these conditions. We showed that expression of 5-HT(2A) receptors was up-regulated in hypertrophic 3T3-L1 adipocytes, which exhibited decreased expression of adiponectin and increased expression of PAI-1. 5-HT(2A) receptor antagonists and suppression of 5-HT(2A) receptor gene expression enhanced adiponectin expression. Activation of Gq negatively regulated adiponectin expression, and inhibition of mitogen-activated protein kinase reversed the Gq-induced effect. Moreover, the 5-HT(2A) receptor blockade reduced PAI-1 expression. These findings indicate that antagonism of 5-HT(2A) receptors in adipocytes could improve the obesity-linked decreases in adiponectin expression and increases in PAI-1 expression.

  2. Urinary excretion of bufotenin (N,N-dimethyl-5-hydroxytryptamine) is increased in suspicious violent offenders: a confirmatory study.

    PubMed

    Kärkkäinen, J; Räisänen, M; Huttunen, M O; Kallio, E; Naukkarinen, H; Virkkunen, M

    1995-09-29

    We previously reported that violent offenders with paranoid symptoms or whose violent actions had been directed against family members had higher urinary levels of bufotenin than other violent offenders. In the present study, patients were evaluated with the Karolinska Scales of Personality (KSP), and urinary levels of bufotenin were determined by mass spectrometry. In drug-free patients suspiciousness was positively correlated, and socialization was negatively correlated, with urinary bufotenin excretion. These two personality variables were strongly interdependent. In drug users, bufotenin excretion was correlated positively with social desirability and negatively with irritability, but not with suspiciousness. Bufotenin excretion was not found to be associated with violence toward family members in the present study. The results are in keeping with the earlier finding that violent offenders with paranoid personality traits have higher urinary levels of bufotenin than other violent offenders.

  3. Improved efficacy of fluoxetine in increasing hippocampal 5-hydroxytryptamine outflow in 5-HT(1B) receptor knock-out mice.

    PubMed

    Malagié, Isabelle; David, Denis J; Jolliet, Pascale; Hen, René; Bourin, Michel; Gardier, Alain M

    2002-05-17

    To test for the contribution of the 5-HT(1B) receptor subtype in mediating the effects of fluoxetine, a selective serotonin reuptake inhibitor (SSRI), we used intracerebral in vivo microdialysis in awake, freely moving 5-HT(1B) receptor knock-out mice. We show that a single systemic administration of fluoxetine (1, 5 or 10 mg/kg, i.p.) increased extracellular serotonin levels [5-HT](ext) in the ventral hippocampus and frontal cortex of wild-type and mutant mice. However, in the ventral hippocampus, fluoxetine, at the three doses studied, induced a larger increase in [5-HT](ext) in knock-out than in wild-type mice. In the frontal cortex, the effect of fluoxetine did not differ between the two genotypes. The region-dependent response to fluoxetine described here in mutants confirms data we recently reported for another SSRI, paroxetine. These data suggest that 5-HT(1B) autoreceptors limit the effects of selective serotonin reuptake inhibitors on dialysate 5-HT levels at serotonergic nerve terminals located mainly in the ventral hippocampus. Alternative mechanisms, e.g., changes in 5-HT transporter and/or 5-HT(1A) receptor density in 5-HT(1B) receptor knock-out mice could also explain these findings.

  4. 5-Hydroxytryptamine1A receptor-activation hyperpolarizes pyramidal cells and suppresses hippocampal gamma oscillations via Kir3 channel activation

    PubMed Central

    Johnston, April; McBain, Chris J; Fisahn, André

    2014-01-01

    Rhythmic cortical neuronal oscillations in the gamma frequency band (30–80 Hz, gamma oscillations) have been associated with cognitive processes such as sensory perception and integration, attention, learning, and memory. Gamma oscillations are disrupted in disorders for which cognitive deficits are hallmark symptoms such as schizophrenia and Alzheimer's disease. In vitro, various neurotransmitters have been found to modulate gamma oscillations. Serotonin (5-HT) has long been known to be important for both behavioural and cognitive functions such as learning and memory. Multiple 5-HT receptor subtypes are expressed in the CA3 region of the hippocampus and high doses of 5-HT reduce the power of induced gamma oscillations. Hypothesizing that 5-HT may have cell- and receptor subtype-specific modulatory effects, we investigated the receptor subtypes, cell types and cellular mechanisms engaged by 5-HT in the modulation of gamma oscillations in mice and rats. We found that 5-HT decreases the power of kainate-induced hippocampal gamma oscillations in both species via the 5-HT1A receptor subtype. Whole-cell patch clamp recordings demonstrated that this decrease was caused by a hyperpolarization of CA3 pyramidal cells and a reduction of their firing frequency, but not by alteration of inhibitory neurotransmission. Finally, our results show that the effect on pyramidal cells is mediated via the G protein-coupled receptor inwardly rectifying potassium channel Kir3. Our findings suggest this novel cellular mechanism as a potential target for therapies that are aimed at alleviating cognitive decline by helping the brain to maintain or re-establish normal gamma oscillation levels in neuropsychiatric and neurodegenerative disorders. PMID:25107925

  5. In vivo modulation of vagal-identified dorsal medullary neurones by activation of different 5-Hydroxytryptamine2 receptors in rats

    PubMed Central

    Sévoz-Couche, Caroline; Spyer, K Michael; Jordan, David

    2000-01-01

    In in vivo experiments, DOI (a 5-HT2 receptor agonist), MK-212 (a 5-HT2C receptor agonist), and BW-723C86 (a 5-HT2B receptor agonist) were applied by ionophoresis to neurones in the rat nucleus tractus solitarius (NTS) receiving vagal afferent input. The majority of the putative ‘monosynaptically' vagal activated cells were inhibited by both MK-212 (4/6) and DOI (2/4), but unaffected by BW-723C86 (12/14). In contrast, ‘polysynaptically' activated NTS cells were excited by both BW-723C86 (13/19) and DOI (9/10). Inactive ‘intermediate' cells were inhibited by BW-723C86 (9/12), MK-212 (5/6) and DOI (3/4), whilst active cells of this group were excited by BW-723C86 (7/13) and DOI (5/5). The selective 5-HT2B receptor antagonist LY-202715 significantly reduced the excitatory actions of BW-723C86 on ‘intermediate' and ‘polysynaptic' cells (13/13), but not the inhibitory effects observed on inactive Group 2 cells (n=5) whereas the selective 5-HT2C receptor antagonist RS-102221 reversed the inhibitory effects of MK-212 and DOI on ‘monosynaptic and ‘intermediate' neurones. Cardio-pulmonary afferent stimulation inhibited two of four putative ‘monosynaptically' activated calls and all four inactive intermediate cells. These were also inhibited by DOI and MK-212. In contrast, cardio-pulmonary afferents excited all five active intermediate cells and all six putative ‘polysynaptically' activated NTS cells, while all were also previously excited by BW-723C86 and/or DOI. In conclusion, these data demonstrate that neurones in the NTS are affected differently by 5-HT2 receptor ligands, in regard of their vagal postsynaptic location, the type of cardio-pulmonary afferent they receive and the different 5-HT2 receptors activated. PMID:11090119

  6. Recombinant glucose uptake system

    DOEpatents

    Ingrahm, Lonnie O.; Snoep, Jacob L.; Arfman, Nico

    1997-01-01

    Recombinant organisms are disclosed that contain a pathway for glucose uptake other than the pathway normally utilized by the host cell. In particular, the host cell is one in which glucose transport into the cell normally is coupled to PEP production. This host cell is transformed so that it uses an alternative pathway for glucose transport that is not coupled to PEP production. In a preferred embodiment, the host cell is a bacterium other than Z. mobilis that has been transformed to contain the glf and glk genes of Z. mobilis. By uncoupling glucose transport into the cell from PEP utilization, more PEP is produced for synthesis of products of commercial importance from a given quantity of biomass supplied to the host cells.

  7. Numerical model for the uptake of groundwater contaminants by phreatophytes

    USGS Publications Warehouse

    Widdowson, M.A.; El-Sayed, A.; Landmeyer, J.E.

    2008-01-01

    Conventional solute transport models do not adequately account for the effects of phreatophytic plant systems on contaminant concentrations in shallow groundwater systems. A numerical model was developed and tested to simulate threedimensional reactive solute transport in a heterogeneous porous medium. Advective-dispersive transport is coupled to biodegradation, sorption, and plantbased attenuation processes including plant uptake and sorption by plant roots. The latter effects are a function of the physical-chemical properties of the individual solutes and plant species. Models for plant uptake were tested and evaluated using the experimental data collected at a field site comprised of hybrid poplar trees. A non-linear equilibrium isotherm model best represented site conditions.

  8. Uptake of VOC by sunflower

    NASA Astrophysics Data System (ADS)

    Folkers, A.; Miebach, M.; Kleist, E.; Wildt, J.

    2003-04-01

    To study potential VOC uptake by plants we exposed sunflower (Helianthus annuus) to different VOC in continuously stirred tank reactors. For many VOC like methanol, ethanol, acetone, methylvinylketone, isoprene or limonene no uptake was detectable within the accuracy of our analytic set up. Other VOC like hexanal, octanal, (E)-3-hexenol and nopinone were taken up by sunflower. The uptake was related to stomatal aperture. Obviously, these VOC enter the plants through stomata. In case of hexanal, octanal, and (E)-3-hexenol the uptake was only limited by stomatal aperture implying that these VOC are rapidly metabolised. For nopinone the uptake seems to be limited by a slow metabolization. Estimations of deposition velocities showed that dry deposition of these compounds cannot be neglected as sink if diffusion through stomata is the limiting step for dry deposition. In such cases the lifetime with respect to dry deposiotion is comparable to the lifetime with respect to oxidation by hydroxyl radicals.

  9. Stimulation-dependent myocardial calcium uptake into slowly exchangeable compartments

    SciTech Connect

    Fintel, M.; Langer, G.A.

    1986-03-01

    Myocardial calcium uptake into slowly exchangeable sites was increased in response to beating following a period of prolonged quiescence (> 1 hr). Net calcium uptake was measured in rabbit interventricular septa using the /sup 45/Ca washout technique. The maximal increment of slowly exchangeable calcium induced by beating was 20 +/- 2% of calcium uptake during quiescence. The increment in calcium uptake induced by 282 beats in 10 minutes did not differ from the increment induced by 60 beats but was significantly greater than the increment induced by 35 and 15 beats. The total number of beats rather than the frequency of stimulation appeared to be the most critical factor which determined the increment in calcium uptake. Based on the increment of 0.12 +/- 0.02 mmoles/kg dry weight obtained when 15 beats occurred in 10 minutes, the minimum amount of calcium which entered slowly exchangeable sites per beat was calculated to be 1 ..mu..mol/kg wet weight. The increment in slowly exchangeable calcium induced by beating was not affected by ryanodine but was inhibited by the metabolic inhibitor CCCP. In conclusion, a net increment in slowly exchangeable calcium occurs when beating is resumed following a period of prolonged quiescence. This suggests that calcium influx exceeds efflux transiently, under these conditions, and that slowly exchangeable sites represent an important mechanism by which a fraction of incoming calcium is buffered.

  10. Light dependence of selenium uptake by phytoplankton and implications for predicting selenium incorporation into food webs

    USGS Publications Warehouse

    Baines, S.B.; Fisher, N.S.; Doblin, M.A.; Cutter, G.A.; Cutter, L.S.; Cole, B.

    2004-01-01

    The potentially toxic element selenium is first concentrated from solution to a large but highly variable degree by algae and bacteria before being passed on to consumers. The large loads of abiotic and detrital suspended particles often present in rivers and estuaries may obscure spatial and temporal patterns in Se concentrations at the base of the food web. We used radiotracers to estimate uptake of both selenite (Se(IV)) and C by intact plankton communities at two sites in the Sacramento/San Joaquin River Delta. Our goals were to determine (1) whether C and Se(IV) uptake were coupled, (2) the role of bacteria in Se(IV) uptake, and (3) the Se:C uptake ratio of newly produced organic material. Se(IV) uptake, like C uptake, was strongly related to irradiance. The shapes of both relationships were very similar except that at least 42-56% of Se(IV) uptake occurred in the dark, whereas C uptake in the dark was negligible. Of this dark Se(IV) uptake, 34-67% occurred in the 0.2-1.0-??m size fraction, indicating significant uptake by bacteria. In addition to dark uptake, total Se(IV) uptake consisted of a light-driven component that was in fixed proportion to C uptake. Our estimates of daily areal Se(IV):C uptake ratios agreed very well with particulate Se:C measured at a site dominated by phytoplankton biomass. Estimates of bacterial Se:C were 2.4-13 times higher than for the phytoplankton, suggesting that bacteriovores may be exposed to higher dietary Se concentrations than herbivores.

  11. Manganese uptake of imprinted polymers

    SciTech Connect

    Susanna Ventura

    2015-09-30

    Batch tests of manganese imprinted polymers of variable composition to assess their ability to extract lithium and manganese from synthetic brines at T=45C . Data on manganese uptake for two consecutive cycles are included.

  12. Characterization of the putative anxiolytic SM-3997 recognition sites in rat brain

    SciTech Connect

    Shimizui, H.; Tatsuno, T.; Kirose, A.; Tanaka, H.; Kumasaka, Y.; Nakamura, M.

    1988-01-01

    In order to clarify the mechanism of action of the putative nonbenzodiazepine anxiolytic SM-3997 ((3a..cap alpha.., 4..beta.., 7..beta.., 7a..cap alpha..)-Hexahydro-2-(4-(4-(2-pyrimidinyl)-1-piperazinyl)-butyl)-4, 7-methano-1H-isoindole-1,3(2H)-dione dihydrogen citrate), in vitro binding studies with radiolabeled compound were performed. /sup 3/H-SM-3997 bound rapidly, reversibly and in a saturable manner with high affinity to rat brain hippocampal membranes (Kd = 9.4 nM, Bmax = 213 fmol/mg protein). This specific binding was displaced by 5-hydroxytryptamine (5-HT) and related compounds. Especially, 8-OH-DPAT, a 5-HT-1A selective agonist, bound with the highest affinity to these binding sites. /sup 3/H-SM-3997 binding, however, was not displaced by a variety of other neurotransmitters, neuropeptides and some other drugs. EDTA and physiological concentration of Na/sup +/ inhibited this specific binding, but several divalent cations, Mn/sup 2 +/, Ca/sup 2 +/ and Mg/sup 2 +/, enhanced this binding. GTP decreased the affinity of these binding sites for /sup 3/H-SM-3997 without changing the number of binding sites, but GMP and ATP did not influence /sup 3/H-SM-399 binding. Furthermore, /sup 3/H-SM-3997 bound with marked regional selectivity to hippocampal membranes. These characteristics and the regional distribution of /sup 3/H-SM-3997 binding sites were very similar to those of /sup 3/H-8-OH-DPAT binding sites (5-HT-1A receptors). Therefore, these results indicate that SM-3997 binds selectively and with high affinity to 5HT-1A receptors in rat brain and may be an agonist.

  13. The Helicobacter pylori HpyAXII restriction–modification system limits exogenous DNA uptake by targeting GTAC sites but shows asymmetric conservation of the DNA methyltransferase and restriction endonuclease components

    PubMed Central

    Humbert, Olivier; Salama, Nina R.

    2008-01-01

    The naturally competent organism Helicobacter pylori encodes a large number of restriction–modification (R–M) systems that consist of a restriction endonuclease and a DNA methyltransferase. R–M systems are not only believed to limit DNA exchange among bacteria but may also have other cellular functions. We report a previously uncharacterized H. pylori type II R–M system, M.HpyAXII/R.HpyAXII. We show that this system targets GTAC sites, which are rare in the H. pylori chromosome but numerous in ribosomal RNA genes. As predicted, this type II R–M system showed attributes of a selfish element. Deletion of the methyltransferase M.HpyAXII is lethal when associated with an active endonuclease R.HpyAXII unless compensated by adaptive mutation or gene amplification. R.HpyAXII effectively restricted both unmethylated plasmid and chromosomal DNA during natural transformation and was predicted to belong to the novel ‘half pipe’ structural family of endonucleases. Analysis of a panel of clinical isolates revealed that R.HpyAXII was functional in a small number of H. pylori strains (18.9%, n = 37), whereas the activity of M.HpyAXII was highly conserved (92%, n = 50), suggesting that GTAC methylation confers a selective advantage to H. pylori. However, M.HpyAXII activity did not enhance H. pylori fitness during stomach colonization of a mouse infection model. PMID:18978016

  14. Characterization of cadmium uptake by the water lily Nymphaea aurora.

    PubMed

    Schor-Fumbarov, Tamar; Keilin, Zvika; Tel-Or, Elisha

    2003-01-01

    This study characterizes cadmium (Cd) uptake by the waterlily Nymphaea aurora, (Nymphaeaceae) in two systems: a model hydroponic Cd solution and heavily polluted sludge from two sites in Israel. The uptake of Cd from hydroponic solution resulted in Cd storage in petioles and laminae of Nymphaea, as well as in the roots. The pH of the solution affected Cd solubility and availability, with pH 5.5 yielding maximum Cd content in the plant (140 mg Cd per g DW). Cd uptake was reduced by the addition of EDTA to the hydroponic growth medium, although EDTA enhanced heavy metal uptake by terrestrial plants. Nymphaea efficiently reduced the concentration of Cd in heavy metal polluted urban and industrial sludge and the amount of Cd uptake was enhanced by the addition of KCl to the sludge and by adjustment of the pH to 5.5. The inherent growth patterns of Nymphaea plants allowed Cd uptake by the shoot and root, and resulted in maximum contact between the various plant parts and the growth media. Thus, Nymphaea has potential as an optimal, highly effective phytoremediation tool for the removal of Cd from polluted waste sources.

  15. Uptake of inert microparticles in normal and immune deficient mice.

    PubMed

    Smyth, S H; Feldhaus, S; Schumacher, U; Carr, K E

    2008-01-01

    Intestinal microparticle uptake is important for drug delivery, environmental pollution and multiple organ dysfunction syndrome. This paper explores further whether uptake occurs at mucosa associated lymphoid tissue (MALT) via the microfold (M) cells of Peyer's patch domes or through villous epithelium. It does this by comparing the results of exposure of either severe combined immunodeficient (SCID) mice (lacking MALT) or normal BALBc mice, to oral gavage with 2 microm fluorescent latex microparticles. At 5 and 30 min after gavage, full circumference samples along the small intestine were processed for fluorescence microscopy and microparticle numbers were collected for surface and tissue sites. Uptake occurred in both BALBc and SCID mice within 5 min of particle administration and increased further in the following 25 min. In BALBc mice, almost all particles (96%) are in non-MALT sites in MALT circumference samples, with very few at the domes: uptake was also substantial in entirely villous samples. In SCID mice, particle numbers were only slightly lower than those of the BALBc mice, and occurred exclusively by the villous route. These findings confirm that the villous uptake route must be considered when assessing the extent of the dose delivered following pharmaceutical or toxicological oral exposure to microparticles. PMID:17723283

  16. Uptake of antibiotics by human polymorphonuclear leukocyte cytoplasts

    SciTech Connect

    Hand, W.L.; King-Thompson, N.L. , Decatur, GA )

    1990-06-01

    Enucleated human polymorphonuclear leukocytes (PMN cytoplasts), which have no nuclei and only a few granules, retain many of the functions of intact neutrophils. To better define the mechanisms and intracellular sites of antimicrobial agent accumulation in human neutrophils, we studied the antibiotic uptake process in PMN cytoplasts. Entry of eight radiolabeled antibiotics into PMN cytoplasts was determined by means of a velocity gradient centrifugation technique. Uptakes of these antibiotics by cytoplasts were compared with our findings in intact PMN. Penicillin entered both intact PMN and cytoplasts poorly. Metronidazole achieved a concentration in cytoplasts (and PMN) equal to or somewhat less than the extracellular concentration. Chloramphenicol, a lipid-soluble drug, and trimethoprim were concentrated three- to fourfold by cytoplasts. An unusual finding was that trimethroprim, unlike other tested antibiotics, was accumulated by cytoplasts more readily at 25 degrees C than at 37 degrees C. After an initial rapid association with cytoplasts, cell-associated imipenem declined progressively with time. Clindamycin and two macrolide antibiotics (roxithromycin, erythromycin) were concentrated 7- to 14-fold by cytoplasts. This indicates that cytoplasmic granules are not essential for accumulation of these drugs. Adenosine inhibited cytoplast uptake of clindamycin, which enters intact phagocytic cells by the membrane nucleoside transport system. Roxithromycin uptake by cytoplasts was inhibited by phagocytosis, which may reduce the number of cell membrane sites available for the transport of macrolides. These studies have added to our understanding of uptake mechanisms for antibiotics which are highly concentrated in phagocytes.

  17. Brain uptake of ketoprofen-lysine prodrug in rats.

    PubMed

    Gynther, Mikko; Jalkanen, Aaro; Lehtonen, Marko; Forsberg, Markus; Laine, Krista; Ropponen, Jarmo; Leppänen, Jukka; Knuuti, Johanna; Rautio, Jarkko

    2010-10-31

    The blood-brain barrier (BBB) controls the entry of xenobiotics into the brain. Often the development of central nervous system drugs needs to be terminated because of their poor brain uptake. We describe a way to achieve large neutral amino acid transporter (LAT1)-mediated drug transport into the rat brain. We conjugated ketoprofen to an amino acid l-lysine so that the prodrug could access LAT1. The LAT1-mediated brain uptake of the prodrug was demonstrated with in situ rat brain perfusion technique. The ability of the prodrug to deliver ketoprofen into the site of action, the brain intracellular fluid, was determined combining in vivo and in vitro experiments. A rapid brain uptake from blood and cell uptake was seen both in in situ and in vivo experiments. Therefore, our results show that a prodrug approach can achieve uptake of drugs via LAT1 into the brain intracellular fluid. The distribution of the prodrug in the brain parenchyma and the site of parent drug release in the brain were shown with in vivo and in vitro studies. In addition, our results show that although lysine or ketoprofen are not LAT1-substrates themselves, by combining these molecules, the formed prodrug has affinity for LAT1. PMID:20727958

  18. Post-uptake metabolism affects quantification of amino acid uptake.

    PubMed

    Warren, Charles R

    2012-01-01

    • The quantitative significance of amino acids to plant nutrition remains controversial. This experiment determined whether post-uptake metabolism and root to shoot export differ between glycine and glutamine, and examined implications for estimation of amino acid uptake. • Field soil containing a Eucalyptus pauciflora seedling was injected with uniformly (13)C- and (15)N-labelled glycine or glutamine. I quantified (15)N and (13)C excess in leaves and roots and intact labelled amino acids in leaves, roots and stem xylem sap. A tunable diode laser quantified fluxes of (12)CO(2) and (13)CO(2) from leaves and soil. • 60-360 min after addition of amino acid, intact molecules of U-(13)C,(15)N glutamine were < 5% of (15)N excess in roots, whereas U-(13)C,(15)N glycine was 30-100% of (15)N excess in roots. Intact molecules of glutamine, but not glycine, were exported from roots to shoots. • Post-uptake metabolism and transport complicate interpretation of isotope labelling such that root and shoot contents of intact amino acid, (13)C and (15)N may not reflect rates of uptake. Future experiments should focus on reconciling discrepancies between intact amino acid, (13)C and (15)N by determining the turnover of amino acids within roots. Alternatively, post-uptake metabolism and transport could be minimized by harvesting plants within minutes of isotope addition.

  19. The MDP skull uptake test: A new diagnostic tool

    SciTech Connect

    Ell, P.J.; Jarritt, P.H.; Cullum, I.; Lui, D.

    1984-01-01

    An original approach to the measurement of bone turnover is presented. With SPECT, the authors have measured in pgr/ml, the uptake of MDP by the skull in man. The Cleon 710 scanner, ring phantoms and bone biopsies were used for ultimate in vivo/in vitro count recovery correlation and calibration. A normal range for 24 patients was found: 8.5 to 19.5 pgr/ml with a mean of 14. For patients with bony metastases (12), the values were: 22.5 to 50, mean of 30. For 5 patients with osteomalacia, the values were 46 to 68, mean of 62: for 12 patients with hyperparathyroidism, the values were 37 to 48.5, mean of 43. In 3 patients with Pagets disease, the values were 58.5 to 75, with a mean of 65. In 76 patients with metastatic disease to bone, the conventional wholebody bone scan was investigated against the following: 24h wholebody retention of MDP (WBR), skull uptake as described and GFR by Cr-51-DTPA. There is a correlation between GFR and WBR - r=0.67. There is a lesser correlation between GFR and skull uptake - r=0.3. There is no correlation between skull uptake and WBR - r=0.1. The comparison of skull uptake data with normal whole body bone scans leads to a significant proportion of cancer patients with positive skull uptake data. Monostotic disease (especially if metabolic in nature) expresses itself by abnormal skull uptake even if the clinical site of abnormality lies outside the skull. This new technique is ideal as a tool to investigate phosphonate concentration in bone. With it, the authors have shown the effect of specific activity of label on skull uptake, which increases as the specific activity of labelled MDP decreases.

  20. Nitrogen Uptake in Spinach

    NASA Astrophysics Data System (ADS)

    Ramirez, J.; VanBenthem, P.

    2013-12-01

    A plant's absorption of nitrogen can be encouraged by a variety of environmental factors, especially the application of fertilizers. As a common limiting factor in plant growth, not up taking enough nitrogen can be a result of an unhealthy plant. Moreover, as farmers seek out methods to increase growth of plants, fertilizers are used as a solution to the issue of nitrogen deficiency to incorporate additional nitrogen from chemical or organic sources, by not using the right fertilizer can greatly affect the plats. The point of this research project is to determine the effect of various fertilizers on the plant growth, and to correlate the measured nitrogen, water and chlorophyll content in spinach leaves. Spinach leaves were used because they are known to quickly uptake chemicals in the environment. The spinach plants were exposed to four different growing parameters, which are referred to as control, ammonium nitrate, MiracleGro , and organic. The spinach was originally placed in nitrogen deficient soil with only 2.2x10 4 weight percent (wt. %) nitrogen. The leaves in the control group were grown in this nitrogen deficient soil without any fertilizer added. Ammomium nitrate and MiracleGro were added to the spinach in the A and MG groups, respectively, and organic chicken stool was used for the O group. By using a spectral imaging system and flame combustion techniques, the chlorophyll content can be related to the nitrogen content in the spinach leaves. In these spinach leaves, nitrogen and chlorophyll content were measured, chlorophyll is a green pigment that plays a crucial role in producing nutrients for green plants. The lack of chlorophyll will allow the plant to become susceptible to diseases, so it is extremely important that the plants have a high content of chlorophyll. The role of nitrogen in chlorophyll is very important and helps in the creation of chlorophyll; therefore it is necessary that an appropriate amount of nitrogen is added for optimal growth

  1. Mechanisms of Ocean Heat Uptake

    NASA Astrophysics Data System (ADS)

    Garuba, Oluwayemi

    An important parameter for the climate response to increased greenhouse gases or other radiative forcing is the speed at which heat anomalies propagate downward in the ocean. Ocean heat uptake occurs through passive advection/diffusion of surface heat anomalies and through the redistribution of existing temperature gradients due to circulation changes. Atlantic meridional overturning circulation (AMOC) weakens in a warming climate and this should slow the downward heat advection (compared to a case in which the circulation is unchanged). However, weakening AMOC also causes a deep warming through the redistributive effect, thus increasing the downward rate of heat propagation compared to unchanging circulation. Total heat uptake depends on the combined effect of these two mechanisms. Passive tracers in a perturbed CO2 quadrupling experiments are used to investigate the effect of passive advection and redistribution of temperature anomalies. A new passive tracer formulation is used to separate ocean heat uptake into contributions due to redistribution and passive advection-diffusion of surface heating during an ocean model experiment with abrupt increase in surface temperature. The spatial pattern and mechanisms of each component are examined. With further experiments, the effects of surface wind, salinity and temperature changes in changing circulation and the resulting effect on redistribution in the individual basins are isolated. Analysis of the passive advection and propagation path of the tracer show that the Southern ocean dominates heat uptake, largely through vertical and horizontal diffusion. Vertical diffusion transports the tracer across isopycnals down to about 1000m in 100 years in the Southern ocean. Advection is more important in the subtropical cells and in the Atlantic high latitudes, both with a short time scale of about 20 years. The shallow subtropical cells transport the tracer down to about 500m along isopycnal surfaces, below this vertical

  2. Through form to function: root hair development and nutrient uptake

    NASA Technical Reports Server (NTRS)

    Gilroy, S.; Jones, D. L.

    2000-01-01

    Root hairs project from the surface of the root to aid nutrient and water uptake and to anchor the plant in the soil. Their formation involves the precise control of cell fate and localized cell growth. We are now beginning to unravel the complexities of the molecular interactions that underlie this developmental regulation. In addition, after years of speculation, nutrient transport by root hairs has been demonstrated clearly at the physiological and molecular level, with evidence for root hairs being intense sites of H(+)-ATPase activity and involved in the uptake of Ca(2+), K(+), NH(4)(+), NO(3)(-), Mn(2+), Zn(2+), Cl(-) and H(2)PO(4)(-).

  3. Presenilin Promotes Dietary Copper Uptake

    PubMed Central

    Southon, Adam; Greenough, Mark A.; Ganio, George; Bush, Ashley I.; Burke, Richard; Camakaris, James

    2013-01-01

    Dietary copper is essential for multicellular organisms. Copper is redox active and required as a cofactor for enzymes such as the antioxidant Superoxide Dismutase 1 (SOD1). Copper dyshomeostasis has been implicated in Alzheimer’s disease. Mutations in the presenilin genes encoding PS1 and PS2 are major causes of early-onset familial Alzheimer’s disease. PS1 and PS2 are required for efficient copper uptake in mammalian systems. Here we demonstrate a conserved role for presenilin in dietary copper uptake in the fly Drosophila melanogaster. Ubiquitous RNA interference-mediated knockdown of the single Drosophila presenilin (PSN) gene is lethal. However, PSN knockdown in the midgut produces viable flies. These flies have reduced copper levels and are more tolerant to excess dietary copper. Expression of a copper-responsive EYFP construct was also lower in the midgut of these larvae, indicative of reduced dietary copper uptake. SOD activity was reduced by midgut PSN knockdown, and these flies were sensitive to the superoxide-inducing chemical paraquat. These data support presenilin being needed for dietary copper uptake in the gut and so impacting on SOD activity and tolerance to oxidative stress. These results are consistent with previous studies of mammalian presenilins, supporting a conserved role for these proteins in mediating copper uptake. PMID:23667524

  4. l-Methionine Placental Uptake

    PubMed Central

    Araújo, João R.; Correia-Branco, Ana; Ramalho, Carla; Gonçalves, Pedro; Pinho, Maria J.; Keating, Elisa

    2013-01-01

    Our aim was to investigate the influence of gestational diabetes mellitus (GDM) and GDM-associated conditions upon the placental uptake of 14C-l-methionine (14C-l-Met). The 14C-l-Met uptake by human trophoblasts (TBs) obtained from normal pregnancies (normal trophoblast [NTB] cells) is mainly system l-type amino acid transporter 1 (LAT1 [L])-mediated, although a small contribution of system y+LAT2 is also present. Comparison of 14C-l-Met uptake by NTB and by human TBs obtained from GDM pregnancies (diabetic trophoblast [DTB] cells) reveals similar kinetics, but a contribution of systems A, LAT2, and b0+ and a greater contribution of system y+LAT1 appears to exist in DTB cells. Short-term exposure to insulin and long-term exposure to high glucose, tumor necrosis factor-α, and leptin decrease 14C-l-Met uptake in a human TB (Bewo) cell line. The effect of leptin was dependent upon phosphoinositide 3-kinase, extracellular-signal-regulated kinase 1/2 (ERK/MEK 1/2), and p38 mitogen-activated protein kinase. In conclusion, GDM does not quantitatively alter 14C-l-Met placental uptake, although it changes the nature of transporters involved in that process. PMID:23653387

  5. Specificity of the antibody receptor site to D-lysergamide: model of a physiological receptor for lysergic acid diethylamide.

    PubMed

    Van Vunakis, H; Farrow, J T; Gjika, H B; Levine, L

    1971-07-01

    Antibodies to D-lysergic acid have been produced in rabbits and guinea pigs and a radioimmunoassay for the hapten was developed. The specificity of this lysergamide-antilysergamide reaction was determined by competitive binding with unlabeled lysergic acid diethylamide (LSD), psychotomimetic drugs, neurotransmitters, and other compounds with diverse structures. LSD and several related ergot alkaloids were potent competitors, three to seven times more potent than lysergic acid itself. The N,N-dimethyl derivatives of several compounds, including tryptamine, 5-hydroxytryptamine, 4-hydroxytryptamine, 5-methoxytryptamine, tyramine, and mescaline, were only about ten times less effective than lysergic acid, even though these compounds lack some of the ring systems of lysergic acid. The pattern of inhibition by related compounds with various substituents suggests that the antibody receptor site recognizes structural features resembling the LSD molecule. In particular, the aromatic nucleus and the dimethylated ethylamine side chain in phenylethylamine and tryptamine derivatives may assume in solution a conformation resembling ring A and the methylated nitrogen in ring C of LSD. Among the tryptamine derivatives, a large percentage of the most potent competitors are also psychotomimetic compounds.

  6. Identification of a new component of the agonist binding site of the nicotinic alpha 7 homooligomeric receptor.

    PubMed

    Corringer, P J; Galzi, J L; Eiselé, J L; Bertrand, S; Changeux, J P; Bertrand, D

    1995-05-19

    Tryptophan 54 of the alpha 7 neuronal nicotinic homooligomeric receptor is homologous to gamma-Trp-55 and delta-Trp-57 of non-alpha subunits of Torpedo receptor labeled by d-tubocurarine. This residue was mutated on the alpha 7-V201-5-hydroxytryptamine (5HT)3 homooligomeric chimera, which displays alpha 7 nicotinic pharmacology, and for which both equilibrium binding studies and electrophysiological recordings could be carried out in parallel. Replacement of Trp-54 by a Phe, Ala, or His causes a progressive decrease both in binding affinity and in responses (EC50 or IC50) for acetylcholine, nicotine, and dihydro-beta-erythroidine, without significant modification in alpha-Bgtx binding. Except for Gln-56, comparatively small effects are observed when the other residues of the 52-58 region are mutated into alanine. These data support the participation of Trp-54 to ligand binding, and provide evidence for a new "complementary component" of the alpha 7 nicotinic binding site, distinct from its three-loop "principal component," and homologous to the "non-alpha component" present on gamma and delta subunits.

  7. Pharmacological characterization of binding sites identified in rat brain following in vivo administration of [3H]-spiperone.

    PubMed Central

    Chivers, J.; Jenner, P.; Marsden, C. D.

    1987-01-01

    [3H]-spiperone is commonly used to label dopamine receptors in vitro in brain tissue. However, spiperone also interacts with brain 5-hydroxytryptamine and noradrenaline receptors. In vivo, [3H]-spiperone has been used for identifying dopamine receptors in both animals and man but the nature of the sites identified is unknown. The in vivo administration of [3H]-spiperone to rats leads to a selective accumulation of radioactivity in the olfactory lobes, tuberculum olfactorium, nucleus accumbens, striatum, substantia nigra, hippocampus, frontal cortex and hypothalamus, when compared to the cerebellum. In vivo drug displacement studies suggest that the binding of [3H]-spiperone in these areas may be to dopamine, 5-HT or noradrenaline receptors. [3H]-spiperone in vivo mainly labels dopamine receptors in striatum, tuberculum olfactorium, hypothalamus, substantia nigra and olfactory lobes. However, in the frontal cortex and nucleus accumbens specific binding involves not only dopamine receptors but also 5-HT and/or noradrenaline receptors. Interpretation of in vivo studies in man using radioactive spiperone and its derivatives must take into account the fact that this ligand only labels dopamine receptors in some brain areas. PMID:2882801

  8. UPTAKE OF RADIONUCLIDE METALS BY SPME FIBERS

    SciTech Connect

    Duff, M; S Crump, S; Robert02 Ray, R; Keisha Martin, K; Donna Beals, D

    2006-08-28

    The Federal Bureau of Investigation (FBI) Laboratory currently does not have on site facilities for handling radioactive evidentiary materials and there are no established FBI methods or procedures for decontaminating high explosive (HE) and fire debris (FD) evidence while maintaining evidentiary value. One experimental method for the isolation of HE and FD residue involves using solid phase microextraction or SPME fibers to remove residue of interest. Due to their high affinity for organics, SPME fibers should have little affinity for most metals. However, no studies have measured the affinity of radionuclides for SPME fibers. The focus of this research was to examine the affinity of dissolved radionuclide ({sup 239/240}Pu, {sup 238}U, {sup 237}Np, {sup 85}Sr, {sup 133}Ba, {sup 137}Cs, {sup 60}Co and {sup 226}Ra) and stable radionuclide surrogate metals (Sr, Co, Ir, Re, Ni, Ba, Cs, Nb, Zr, Ru, and Nd) for SPME fibers at the exposure conditions that favor the uptake of HE and FD residues. Our results from radiochemical and mass spectrometric analyses indicate these metals have little measurable affinity for these SPME fibers during conditions that are conducive to HE and FD residue uptake with subsequent analysis by liquid or gas phase chromatography with mass spectrometric detection.

  9. Crystal structure of acetylcholine-binding protein from Bulinus truncatus reveals the conserved structural scaffold and sites of variation in nicotinic acetylcholine receptors.

    PubMed

    Celie, Patrick H N; Klaassen, Remco V; van Rossum-Fikkert, Sarah E; van Elk, René; van Nierop, Pim; Smit, August B; Sixma, Titia K

    2005-07-15

    The crystal structure of acetylcholine-binding protein (AChBP) from the mollusk Lymnaea stagnalis is the established model for the ligand binding domains of the ligand-gated ion channel family, which includes nicotinic acetylcholine, 5-hydroxytryptamine (5-HT3), gamma-aminobutyric acid (GABA), types A and C, and glycine receptors. Here we present the crystal structure of a remote homolog, AChBP from Bulinus truncatus, which reveals both the conserved structural scaffold and the sites of variation in this receptor family. These include rigid body movements of loops that are close to the transmembrane interface in the receptors and changes in the intermonomer contacts, which alter the pentamer stability drastically. Structural, pharmacological and mutational analysis of both AChBPs shows how 3 amino acid changes in the binding site contribute to a 5-10-fold difference in affinity for nicotinic ligands. Comparison of these structures will be valuable for improving structure-function studies of ligand-gated ion channel receptors, including signal transduction, homology modeling, and drug design. PMID:15899893

  10. Comparison of characteristics of dopamine uptake and mazindol binding in mouse striatum.

    PubMed

    Zimányi, I; Lajtha, A; Reith, M E

    1989-12-01

    Biochemical and pharmacological studies suggest that the binding of [3H]mazindol is functionally related to the dopamine uptake carrier complex in rodent striatum. In order to study further the relationship between the substrate recognition site for dopamine uptake and the high-affinity binding site for mazindol the uptake of [3H]dopamine and the binding of [3H]mazindol was studied in BALB/cBy mouse striatum in various buffers (Tris, HEPES, bicarbonate-phosphate). Kinetic analysis showed that the Kd of the binding of [3H]mazindol and the Km of the uptake of [3H]dopamine was changed by different sodium concentrations and/or by the presence of Tris, while the Bmax and the Vmax remained essentially the same. However, the shape of the Na+ dependency curves was not the same for mazindol binding and dopamine uptake in the various buffers. The inhibitory effect of other cations such as K+ and Tris was also different on binding and uptake under similar experimental circumstances. Dopamine did not slow down the dissociation of mazindol from its site and this effect was not sodium-sensitive. These complexities can be accommodated by a model that involves overlapping sites for mazindol and dopamine on the dopamine uptake carrier complex, and translocation-reorientation steps. PMID:2615854

  11. Uptake of atmospheric tritium by market foods

    SciTech Connect

    Inoue, Y.; Tanaka-Miyamoto, K.; Iwakura, T. )

    1992-03-01

    In this paper uptake of tritium by market foods from tritiated water vapor in the air is investigated using cereals and beans purchased in Deep River, Canada. The concentrations of tissue free water tritium (TFWT) and organically bound tritium (OBT) range from 12 to 79% and from 10 to 38% respectively, of that estimated for atmospheric water vapor of the sampling month. The specific activity ratios of OBT to TFWT were constant for cereals, but variable for beans. The elevated OBT was shown to be the result of isotopic exchange of labile hydrogen by the fact that washing the foods with tritium free-water reduced their tritium contents to levels characteristic of their production sites.

  12. Pulmonary uptake of morphine (M)

    SciTech Connect

    Roerig, D.L.; Bunke, S.S.; Kotrly, K.J.; Dawson, C.A.; Kampine, J.P.

    1986-03-01

    Previously the authors reported less than 5% of M was taken up during the first pass through the human lung. The low uptake of this basic lipophilic amine was further investigated in a single pass isolated perfused rat lung (IPL) in comparison to uptake of radiolabelled H/sub 2/O, antipyrine (A), aminopyrine (AM), nicotine (N) and phenylethylamine (P). The IPL was perfused for 5 min with each drug (5nmol/ml) and effluent collected in 10 sec fractions. Pulmonary extraction was calculated using indocyanine green dye as a non-extractable reference indicator. Accumulation of all compounds in the IPL reached an apparent equilibrium within 4 min. At equilibrium lung/perfusate conc. ratios for H/sub 2/O, A, AM, N, P and M were 1.04, 0.84, 0.85, 1.44, 2.57 and 1.13 respectively. The time course of M uptake differed from the other compounds since initial extraction of M was low (23%) compared to 75%, 53%, 35%, 82% and 86% for H/sub 2/O, A, AM, N and P respectively. Also, the half time to equilibrium for M was longer (50 sec) compared to 18, 21, 26, 19 and 22 sec for H/sub 2/O, A, AM, N and P respectively. The low initial pulmonary extraction of M compared to these compounds followed by greater M extraction during the remainder of drug infusion suggests uptake mechanisms for M different than the flow limited uptake for water and other basic amine drugs.

  13. Lithium isotope fractionation during uptake by gibbsite

    NASA Astrophysics Data System (ADS)

    Wimpenny, Josh; Colla, Christopher A.; Yu, Ping; Yin, Qing-Zhu; Rustad, James R.; Casey, William H.

    2015-11-01

    The intercalation of lithium from solution into the six-membered μ2-oxo rings on the basal planes of gibbsite is well-constrained chemically. The product is a lithiated layered-double hydroxide solid that forms via in situ phase change. The reaction has well established kinetics and is associated with a distinct swelling of the gibbsite as counter ions enter the interlayer to balance the charge of lithiation. Lithium reacts to fill a fixed and well identifiable crystallographic site and has no solvation waters. Our lithium-isotope data shows that 6Li is favored during this intercalation and that the solid-solution fractionation depends on temperature, electrolyte concentration and counter ion identity (whether Cl-, NO3- or ClO4-). We find that the amount of isotopic fractionation between solid and solution (ΔLisolid-solution) varies with the amount of lithium taken up into the gibbsite structure, which itself depends upon the extent of conversion and also varies with electrolyte concentration and in the counter ion in the order: ClO4- < NO3- < Cl-. Higher electrolyte concentrations cause more rapid expansion of the gibbsite interlayer and some counter ions, such as Cl-, are more easily taken up than others, probably because they ease diffusion. The relationship between lithium loading and ΔLisolid-solution indicates two stages: (1) uptake into the crystallographic sites that favors light lithium, in parallel with adsorption of solvated cations, and (2) continued uptake of solvated cations after all available octahedral vacancies are filled; this second stage has no isotopic preference. The two-step reaction progress is supported by solid-state NMR spectra that clearly resolve a second reservoir of lithium in addition to the expected layered double-hydroxide phase.

  14. Polyamine Uptake, Kinetics, and Competition among Polyamines and between Polyamines and Inorganic Cations.

    PubMed

    Pistocchi, R; Bagni, N; Creus, J A

    1986-02-01

    Polyamine uptake, the kinetics of this uptake, and the competition among polyamines and between polyamines and inorganic cations were studied in petals of Saintpaulia ionantha Wendl. Uptake experiments using (14)C-labeled polyamines were carried out on single petals, at room temperaure (20 degrees C) and in the light. The results show that putrescine, spermidine, and spermine uptake was dependent on the external pH and occurred up to high external polyamine concentrations with K(m) values of 8.6, 1.2, and 2.1 millimolar, respectively, with spermidine being the most absorbed at low concentration (17 micromolar). Putrescine and spermidine did not seem to compete for the same site of absorption. Furthermore, putrescine and spermidine uptake was not inhibited by Ca(2+), Mg(2+), and K(+) at the same concentrations (17 micromolar), whereas 1.7 millimolar Ca(2+) inhibited and K(+) enhanced spermidine uptake. The intracellular localization of the absorbed putrescine was determined using two different methods. Very little label was found in the apoplast, while most of it was localized in the 98,500g supernatant. According to our data the vacuole, which represents a substantial part of Saintpaulia parenchyma cells, could be a site of putrescine accumulation. 2,4-Dinitrophenol and diethylstilbestrol did not inhibit uptake; however, at 0 degrees C there was a 35% inhibition of spermidine uptake, compared with the controls kept at 20 degrees C as well as a 68% inhibition with 20 millimolar NaSCN. PMID:16664661

  15. Uptake of auxins into membrane vesicles isolated from pea stems: an in vitro auxin transport system

    SciTech Connect

    Slone, J.H.

    1985-01-01

    The objective of this research was to test the applicability of the chemiosmotic theory of auxin transport to a subcellular system. Membrane vesicles were isolated from the basal portion of the third internode of etiolated pea plants (Pisum sativum L. var. Alaska) by differential centrifugation. Uptake of auxin was determined by adding /sup 14/C-labeled indoleacetic acid (IAA) to vesicles. Nigericin, a monovalent cation ionophore, and the electrogenic protonophore, carbonyl-cyanide m-chlorophenylhydrazone (CCCP), at micromolar concentrations abolished saturable uptake. Bursting vesicles by sonication, osmotic shock and freeze/thawing also eliminated saturable uptake. As the temperature increased from 0 to 30/sup 0/C, saturable uptake decreased markedly. Nonsaturable auxin uptake was less affected by these treatments. The pH gradient-dependent uptake of auxin appeared to be a transmembrane uptake of auxin into the vesicles rather than surface binding. Unlabeled IAA, 2,4-dichlorophenoxyacetic acid (2,4-D) and 2-naphthaleneacetic acid (NAA) at low concentrations reduced the saturable accumulation of (/sup 14/C)IAA in vesicles, while phenylacetic acid, benzoic acid, and 1-NAA were effective only at high concentrations. Kinetic analysis revealed two types of sites: a high affinity site with an uptake capacity of 25 to 40 pmoles/g tissue, and a low affinity site with an uptake capacity of 260 to 600 pmole/g tissue, fresh wt. In conclusion, several principal elements of an auxin transport system, as specific by the chemiosmotic theory of polar auxin transport, were present in membrane vesicles isolated from relatively mature pea stem tissue. However, one important aspect of the theory was not demonstrated in this in vitro system - a TIBA/NPA-sensitive auxin efflux. The kinetics and specificity of auxin uptake strongly suggested that this system was physiologically significant.

  16. Anorectic activities of serotonin uptake inhibitors: correlation with their potencies at inhibiting serotonin uptake in vivo and /sup 3/H-mazindol binding in vitro

    SciTech Connect

    Angel, I.; Taranger, M.A.; Claustre, Y.; Scatton, B.; Langer, S.Z.

    1988-01-01

    The mechanism of anorectic action of several serotonin uptake inhibitors was investigated by comparing their anorectic potencies with several biochemical and pharmacological properties and in reference to the novel compound SL 81.0385. The anorectic effect of the potent serotonin uptake inhibitor SL 81.0385 was potentiated by pretreatment with 5-hydroxytryptophan and blocked by the serotonin receptor antagonist metergoline. A good correlation was obtained between the ED/sub 50/ values of anorectic action and the ED/sub 50/ values of serotonin uptake inhibition in vivo (but not in vitro) for several specific serotonin uptake inhibitors. Most of the drugs tested displaced (/sup 3/H)-mazindol from its binding to the anorectic recognition site in the hypothalamus, except the pro-drug zimelidine which was inactive. Excluding zimelidine, a good correlation was obtained between the affinities of these drugs for (/sup 3/H)-mazindol binding and their anorectic action indicating that their anorectic activity may be associated with an effect mediated through this site. Taken together these results suggest that the anorectic action of serotonin uptake inhibitors is directly associated to their ability to inhibit serotonin uptake and thus increasing the synaptic levels of serotonin. The interactions of these drugs with the anorectic recognition site labelled with (/sup 3/H)-mazindol is discussed in connection with the serotonergic regulation of carbohydrate intake.

  17. Site Partition: Turning One Site into Two for Adsorbing CO2.

    PubMed

    Tian, Ziqi; Dai, Sheng; Jiang, De-En

    2016-07-01

    We propose the concept of site partition to explain the role of guest molecules in increasing CO2 uptake in metal-organic frameworks and to design new covalent porous materials for CO2 capture. From grand canonical Monte Carlo simulations of CO2 sorption in the recently synthesized CPM-33 MOFs, we show that guest insertion divides one open metal site into two relatively strong binding sites, hence dramatically increasing CO2 uptake. Further, we extend the site partition concept to covalent organic frameworks with large free volume. After insertion of a designed geometry-matching guest, we show that the volumetric uptake of CO2 doubles. Therefore, the concept of site partition can be used to engineer the pore space of nanoporous materials for higher gas uptake. PMID:27320252

  18. Cellular uptake of metallated cobalamins.

    PubMed

    Tran, Mai Thanh Quynh; Stürup, Stefan; Lambert, Ian Henry; Gammelgaard, Bente; Furger, Evelyne; Alberto, Roger

    2016-03-01

    Cellular uptake of vitamin B12-cisplatin conjugates was estimated via detection of their metal constituents (Co, Pt, and Re) by inductively coupled plasma mass spectrometry (ICP-MS). Vitamin B12 (cyano-cob(iii)alamin) and aquo-cob(iii)alamin [Cbl-OH2](+), which differ in the β-axial ligands (CN(-) and H2O, respectively), were included as control samples. The results indicated that B12 derivatives delivered cisplatin to both cellular cytosol and nuclei with an efficiency of one third compared to the uptake of free cisplatin cis-[Pt(II)Cl2(NH3)2]. In addition, uptake of charged B12 derivatives including [Cbl-OH2](+), [{Co}-CN-{cis-PtCl(NH3)2}](+), [{Re}-{Co}-CN-{cis-PtCl(NH3)2}](+), and [{Co}-CN-{trans-Pt(Cyt)(NH3)2}](2+) (Cyt = cytarabin) was high compared to neutral B12, which implied the existence of an additional internalization pathway for charged B12 vitamin analogs. The affinities of the charged B12 derivatives to the B12 transporters HC, IF and TC were similar to that of native vitamin B12. PMID:26739575

  19. Macroscopic modeling of plant water uptake: soil and root resistances

    NASA Astrophysics Data System (ADS)

    Vogel, Tomas; Votrubova, Jana; Dohnal, Michal; Dusek, Jaromir

    2014-05-01

    The macroscopic physically-based plant root water uptake (RWU) model, based on water-potential-gradient formulation (Vogel et al., 2013), was used to simulate the observed soil-plant-atmosphere interactions at a forest site located in a temperate humid climate of central Europe and to gain an improved insight into the mutual interplay of RWU parameters that affects the soil water distribution in the root zone. In the applied RWU model, the uptake rates are directly proportional to the potential gradient and indirectly proportional to the local soil and root resistances to water flow. The RWU algorithm is implemented in a one-dimensional dual-continuum model of soil water flow based on Richards' equation. The RWU model is defined by four parameters (root length density distribution, average active root radius, radial root resistance, and the threshold value of the root xylem potential). In addition, soil resistance to water extraction by roots is related to soil hydraulic conductivity function and actual soil water content. The RWU model is capable of simulating both the compensatory root water uptake, in situations when reduced uptake from dry layers is compensated by increased uptake from wetter layers, and the root-mediated hydraulic redistribution of soil water, contributing to more natural soil moisture distribution throughout the root zone. The present study focusses on the sensitivity analysis of the combined soil water flow and RWU model responses in respect to variations of RWU model parameters. Vogel T., M. Dohnal, J. Dusek, J. Votrubova, and M. Tesar. 2013. Macroscopic modeling of plant water uptake in a forest stand involving root-mediated soil-water redistribution. Vadose Zone Journal, 12, 10.2136/vzj2012.0154.

  20. Detecting spatio-temporal controls on depth distributions of root water uptake using soil moisture patterns

    NASA Astrophysics Data System (ADS)

    Blume, Theresa; Heidbüchel, Ingo; Simard, Sonia; Güntner, Andreas; Weiler, Markus

    2016-04-01

    Landscape scale soil moisture patterns show a pronounced shift when plants become active during the growing season. Soil moisture patterns are then not only controlled by soils, topography and related abiotic site characteristics as well as site characteristic throughfall patterns but also by root water uptake. In this study root water uptake from different soil depths is estimated based on diurnal fluctuations in soil moisture content and was investigated with a setup of 15 field sites in a forest in northeastern Germany. These sites cover different topographic positions and forest stands. Vegetation types include pine forest (young and old) and different deciduous forest stands. Available data at all sites includes information at high temporal resolution from 5 soil moisture and soil temperature profiles, matric potential, piezometers and sapflow sensors as well as standard climate data. The resulting comprehensive data set of depth distributed root water uptake shows differences in overall amounts as well as in uptake depth distributions between different forest stands, but also related to slope position and thus depth to groundwater. Temporal dynamics of signal strength within the profile suggest a locally shifting spatial distribution of root water uptake depending on water availability. The relative contributions of the different depths to overall root water uptake shift as the summer progresses. However, the relationship of these depth resolved uptake rates to overall soil water availability varies considerably between tree species. This unique data set of depth specific contributions to root water uptake down to a depth of 2 m allows a much more detailed analysis of tree response to water availability than the more common transpiration estimates generated by sapflow or eddy flux measurements.

  1. Measurement of Glucose Uptake in Cultured Cells.

    PubMed

    Yamamoto, Norio; Ueda-Wakagi, Manabu; Sato, Takuya; Kawasaki, Kengo; Sawada, Keisuke; Kawabata, Kyuichi; Akagawa, Mitsugu; Ashida, Hitoshi

    2015-12-08

    Facilitative glucose uptake transport systems are ubiquitous in animal cells and are responsible for transporting glucose across cell surface membranes. Evaluation of glucose uptake is crucial in the study of numerous diseases and metabolic disorders such as myocardial ischemia, diabetes mellitus, and cancer. Detailed in this unit are laboratory methods for assessing glucose uptake into mammalian cells. The unit is divided into five sections: (1) a brief overview of glucose uptake assays in cultured cells; (2) a method for measuring glucose uptake using radiolabeled 3-O-methylglucose; (3) a method for measuring glucose uptake using radiolabeled 2-deoxyglucose (2DG); (4) a microplate method for measuring 2DG-uptake using an enzymatic, fluorometric assay; and (5) a microplate-based method using a fluorescent analog of 2DG.

  2. A mechanism for the hydrogen uptake process in zirconium alloys

    NASA Astrophysics Data System (ADS)

    Cox, B.

    1999-01-01

    Hydrogen uptake data for thin Zircaloy-2 specimens in steam at 300-400°C have been analysed to show that there is a decrease in the rate of uptake with respect to the rate of oxidation when the terminal solid solubility (TSS) of hydrogen in the metal is exceeded. In order for TSS to be reached during pre-transition oxidation a very thin 0.125 mm Zircaloy sheet was used. The specimens had been pickled initially removing all Zr 2(Fe/Ni) particles from the initial surfaces, yet the initial hydrogen uptake rates were still much higher than for Zircaloy-4 or a binary Zr/Fe alloy that did not contain phases that dissolve readily during pickling. Cathodic polarisation at room temperature in CuSO 4 solution showed that small cracks or pores formed the cathodic sites in pre-transition oxide films. Some were at pits resulting from the initial dissolution of the Zr 2(Fe/Ni) phase; others were not; none were at the remaining intermetallics in the original surface. These small cracks are thought to provide the ingress routes for hydrogen. A microscopic steam starvation process at the bottoms of these small cracks or pores, leading to the accumulation of hydrogen adjacent to the oxide/metal interface, and causing breakdown of the passive oxide forming at the bottom of the flaw, is thought to provide the mechanism for the hydrogen uptake process during both pre-transition and post-transition oxidation.

  3. DNA Uptake by Transformable Bacteria

    SciTech Connect

    Lacks, Sanford A.

    1999-03-31

    The various processes of DNA uptake by cells can be categorized as: viral DNA entry, conjugation, or transformation. Within each category, a variety of mechanisms have been found. However, considerable similarities occur among the different mechanisms of conjugation and, especially, transformation. All of these natural mechanisms of DNA transfer are quite elaborate and involve multiple protein components, as the case may be, of the virus, the donor cell, and the recipient cell. The mechanisms of viral infection and conjugation will be discussed mainly with respect to their relevance to transformation.

  4. DNA UPTAKE BY TRANSFORMABLE BACTERIA

    SciTech Connect

    LACKS,S.A.

    1999-09-07

    The various processes of DNA uptake by cells can be categorized as: viral DNA entry, conjugation, or transformation. Within each category, a variety of mechanisms have been found. However, considerable similarities occur among the different mechanisms of conjugation and, especially, transformation. All of these natural mechanisms of DNA transfer are quite elaborate and involve multiple protein components, as the case may be, of the virus, the donor cell, and the recipient cell. The mechanisms of viral infection and conjugation will be discussed mainly with respect to their relevance to transformation.

  5. Ocean uptake of carbon dioxide

    SciTech Connect

    Peng, Tsung-Hung; Takahashi, Taro

    1993-06-01

    Factors controlling the capacity of the ocean for taking up anthropogenic C0{sup 2} include carbon chemistry, distribution of alkalinity, pCO{sup 2} and total concentration of dissolved C0{sup 2}, sea-air pCO{sup 2} difference, gas exchange rate across the sea-air interface, biological carbon pump, ocean water circulation and mixing, and dissolution of carbonate in deep sea sediments. A general review of these processes is given and models of ocean-atmosphere system based on our understanding of these regulating processes axe used to estimate the magnitude of C0{sup 2} uptake by the ocean. We conclude that the ocean can absorb up to 35% of the fossil fuel emission. Direct measurements show that 55% Of C0{sup 2} from fossil fuel burning remains in the atmosphere. The remaining 10% is not accounted for by atmospheric increases and ocean uptake. In addition, it is estimated that an amount equivalent to 30% of recent annual fossil fuel emissions is released into the atmosphere as a result of deforestation and farming. To balance global carbon budget, a sizable carbon sink besides the ocean is needed. Storage of carbon in terrestrial biosphere as a result of C0{sup 2} fertilization is a potential candidate for such missing carbon sinks.

  6. Ocean uptake of carbon dioxide

    SciTech Connect

    Peng, Tsung-Hung ); Takahashi, Taro . Lamont-Doherty Earth Observatory)

    1993-01-01

    Factors controlling the capacity of the ocean for taking up anthropogenic C0[sup 2] include carbon chemistry, distribution of alkalinity, pCO[sup 2] and total concentration of dissolved C0[sup 2], sea-air pCO[sup 2] difference, gas exchange rate across the sea-air interface, biological carbon pump, ocean water circulation and mixing, and dissolution of carbonate in deep sea sediments. A general review of these processes is given and models of ocean-atmosphere system based on our understanding of these regulating processes axe used to estimate the magnitude of C0[sup 2] uptake by the ocean. We conclude that the ocean can absorb up to 35% of the fossil fuel emission. Direct measurements show that 55% Of C0[sup 2] from fossil fuel burning remains in the atmosphere. The remaining 10% is not accounted for by atmospheric increases and ocean uptake. In addition, it is estimated that an amount equivalent to 30% of recent annual fossil fuel emissions is released into the atmosphere as a result of deforestation and farming. To balance global carbon budget, a sizable carbon sink besides the ocean is needed. Storage of carbon in terrestrial biosphere as a result of C0[sup 2] fertilization is a potential candidate for such missing carbon sinks.

  7. Pulmonary uptake of liposomal phosphatidylcholine.

    PubMed

    Zachman, R D; Tsao, F H

    1980-01-01

    Liposomes prepared with phosphatidylcholine (PC) labeled with [1-14C]-dipalmitoyl-PC, dicetylphosphate, cholesterol (molar ratio 7:2:1) were injected into the right ear vein of 2-month-old male rabbits. At 5, 60, and 120 min after injection, organs were removed and analyzed for [14C]-PC. Lung, liver, and spleen took up the [14C]-PC by 5 min. Spleen accumulation of [14C]-PC increased steadily, liver plateaued from 1--2 hr, and lung fell rapidly. The uptake of liposomal [14C]-PC by lung and liver was dependent on the concentration of iv injected liposomal [14C]-PC. All lung subcellular fractions (lamellar bodies, mitochondria, and microsomes) took up [14C]-PC. Lamellar body [14C]-PC was highest at 5 min, and then decreased. Still, on a nmole/mg protein basis, uptake of [14C]-PC by lamellar bodies was higher than other organelle fractions. Of the radioactivity in lung, 95% was [14C]-PC even after 2 hr, whereas by 1 hr, 28% of liposomal PC absorbed by liver had been degraded. PMID:7360518

  8. Uptake of Workplace HIV Counselling and Testing: A Cluster-Randomised Trial in Zimbabwe

    PubMed Central

    Corbett, Elizabeth L; Dauya, Ethel; Matambo, Ronnie; Cheung, Yin Bun; Makamure, Beauty; Bassett, Mary T; Chandiwana, Steven; Munyati, Shungu; Mason, Peter R; Butterworth, Anthony E; Godfrey-Faussett, Peter; Hayes, Richard J

    2006-01-01

    Background HIV counselling and testing is a key component of both HIV care and HIV prevention, but uptake is currently low. We investigated the impact of rapid HIV testing at the workplace on uptake of voluntary counselling and testing (VCT). Methods and Findings The study was a cluster-randomised trial of two VCT strategies, with business occupational health clinics as the unit of randomisation. VCT was directly offered to all employees, followed by 2 y of open access to VCT and basic HIV care. Businesses were randomised to either on-site rapid HIV testing at their occupational clinic (11 businesses) or to vouchers for off-site VCT at a chain of free-standing centres also using rapid tests (11 businesses). Baseline anonymised HIV serology was requested from all employees. HIV prevalence was 19.8% and 18.4%, respectively, at businesses randomised to on-site and off-site VCT. In total, 1,957 of 3,950 employees at clinics randomised to on-site testing had VCT (mean uptake by site 51.1%) compared to 586 of 3,532 employees taking vouchers at clinics randomised to off-site testing (mean uptake by site 19.2%). The risk ratio for on-site VCT compared to voucher uptake was 2.8 (95% confidence interval 1.8 to 3.8) after adjustment for potential confounders. Only 125 employees (mean uptake by site 4.3%) reported using their voucher, so that the true adjusted risk ratio for on-site compared to off-site VCT may have been as high as 12.5 (95% confidence interval 8.2 to 16.8). Conclusions High-impact VCT strategies are urgently needed to maximise HIV prevention and access to care in Africa. VCT at the workplace offers the potential for high uptake when offered on-site and linked to basic HIV care. Convenience and accessibility appear to have critical roles in the acceptability of community-based VCT. PMID:16796402

  9. Is the effect of silicon on rice uptake of arsenate (AsV) related to internal silicon concentrations, iron plaque and phosphate nutrition?

    PubMed

    Guo, W; Zhu, Y-G; Liu, W-J; Liang, Y-C; Geng, C-N; Wang, S-G

    2007-07-01

    Solution culture experiments were conducted to investigate the effects of silicon (Si) on arsenate (As(V)) uptake by rice. The addition of Si to the pretreatment or uptake solution significantly decreased shoot and root As concentrations (P<0.001 and P<0.05). The presence of Si in the pretreatment or uptake solution also significantly decreased shoot P concentrations (P<0.001). The data demonstrated that both internal and external Si inhibited the uptake of As and P. Results of As uptake kinetics showed that the mechanism of the effect of Si on arsenate uptake is not caused by direct competition for active sites of transporters with As. The effect of Si on As uptake was not entirely mediated through the effect of Si on P uptake. Although the addition of Si to pretreatment solutions still significantly decreased shoot and root As concentrations, the extent of reduction became smaller when rice roots were coated with iron plaque. PMID:17175078

  10. Is the effect of silicon on rice uptake of arsenate (AsV) related to internal silicon concentrations, iron plaque and phosphate nutrition?

    PubMed

    Guo, W; Zhu, Y-G; Liu, W-J; Liang, Y-C; Geng, C-N; Wang, S-G

    2007-07-01

    Solution culture experiments were conducted to investigate the effects of silicon (Si) on arsenate (As(V)) uptake by rice. The addition of Si to the pretreatment or uptake solution significantly decreased shoot and root As concentrations (P<0.001 and P<0.05). The presence of Si in the pretreatment or uptake solution also significantly decreased shoot P concentrations (P<0.001). The data demonstrated that both internal and external Si inhibited the uptake of As and P. Results of As uptake kinetics showed that the mechanism of the effect of Si on arsenate uptake is not caused by direct competition for active sites of transporters with As. The effect of Si on As uptake was not entirely mediated through the effect of Si on P uptake. Although the addition of Si to pretreatment solutions still significantly decreased shoot and root As concentrations, the extent of reduction became smaller when rice roots were coated with iron plaque.

  11. Uptake of technetium-99m methylene diphosphonate by fractured and osteoporotic bone after a pulse dose of Vitamin D/sub 3/. [Rats

    SciTech Connect

    Carr, E.A. Jr.; Carroll, M.; Montes, M.; Zielezny, M.

    1985-04-01

    The effect of a pulse dose of Vitamin D/sub 3/ on uptake of (/sup 99m/Tc)MDP by fractured and osteoporotic bone, respectively, was compared with D/sub 3/'s effect on uptake by normal bone in rats. At 4, 7, and 14 days, respectively, after femoral fracture, basal uptake was significantly increased at the fracture site by 336.8, 276.1, and 183.5%, respectively, over the contralateral control site. D/sub 3/-treated rats had lower uptakes than untreated controls at all three fracture sites and at 12 of 15 normal bone sites but analysis of variance showed the uptake differences were not significant. Cortisone-induced osteoporosis caused a significant decrease in basal uptake. The decrease occurred in all nine bone areas studied. D/sub 3/ caused a significant increase in uptake by these osteoporotic bones, but a significant decrease in uptake by the same bones in normal controls. Thus, D/sub 3/ had an effect on uptake by the bone lesion, osteoporosis, that differed from D/sub 3/'s effect on uptake by fracture or normal bone.

  12. Cell uptake survey of pegylated nanographene oxide

    NASA Astrophysics Data System (ADS)

    Vila, M.; Portolés, M. T.; Marques, P. A. A. P.; Feito, M. J.; Matesanz, M. C.; Ramírez-Santillán, C.; Gonçalves, G.; Cruz, S. M. A.; Nieto, A.; Vallet-Regi, M.

    2012-11-01

    Graphene and more specifically, nanographene oxide (GO) has been proposed as a highly efficient antitumoral therapy agent. Nevertheless, its cell uptake kinetics, its influence in different types of cells and the possibility of controlling cellular internalization timing, is still a field that remains unexplored. Herein, different cell types have been cultured in vitro for several incubation periods in the presence of 0.075 mg ml-1 pegylated GO solutions. GO uptake kinetics revealed differences in the agent’s uptake amount and speed as a function of the type of cell involved. Osteoblast-like cells GO uptake is higher and faster without resulting in greater cell membrane damage. Moreover, the dependence on the commonly used PEG nature (number of branches) also influences the viability and cell uptake speed. These facts play an important role in the future definition of timing parameters and selective cell uptake control in order to achieve an effective therapy.

  13. Neutrophil uptake of vaccinia virus in vitro

    SciTech Connect

    West, B.C.; Eschete, M.L.; Cox, M.E.; King, J.W.

    1987-10-01

    We studied human neutrophils for uptake of vaccinia virus. Uptake was determined radiometrically and by electron microscopy. Vaccinia virus was labeled with /sup 14/C or /sup 3/H, incubated with neutrophils, and quantified in neutrophil pellets in a new radiometric phagocytosis assay. Better results were obtained from assays of (/sup 3/H)thymidine-labeled virus; uptake increased through 1 hr and then plateaued. Phagocytosis of 3H-labeled Staphylococcus aureus was normal. Uptake of virus was serum dependent. Hexose monophosphate shunt activity was measured by two methods. No /sup 14/CO/sub 2/ from (/sup 14/C)1-glucose accompanied uptake of vaccinia virus, in contrast to the respiratory burst accompanying bacterial phagocytosis. Electron microscopy showed intact to slightly digested intraphagolysosomal vaccinia virus. Pock reduction assay showed a decrease in viral content due to neutrophils until 6 hr of incubation, when a modest but significant increase was observed. Thus, neutrophil uptake of vaccinia virus is distinguished from bacterial phagocytosis.

  14. Ethanol intake and sup 3 H-serotonin uptake II: A study in alcoholic patients using platelets sup 3 H-paroxetine binding

    SciTech Connect

    Daoust, M.; Boucly, P. ); Ernouf, D. ); Breton, P. ); Lhuintre, J.P.

    1991-01-01

    The kinetic parameters of {sup 3}H-paroxetine binding and {sup 3}H-serotonin uptake were studied in platelets of alcoholic patients. There was no difference between alcoholic and non alcoholic subjects in {sup 3}H-paroxetine binding. When binding and {sup 3}H-serotonin uptake were studied, in the same plasma of the same subjects, the Vmax of serotonin uptake was increased in alcoholics. The data confirm the involvement of serotonin uptake system in alcohol dependance and suggest that serotonin uptake and paroxetine binding sites may be regulated independently in this pathology.

  15. Monitoring iron uptake by siderophores.

    PubMed

    Hoegy, Françoise; Schalk, Isabelle J

    2014-01-01

    Iron is an important element for almost all forms of life. In order to get access to this essential nutriment, Pseudomonads produce two major siderophores, pyoverdine PVD and pyochelin (PCH). Uptake of iron in bacterial cells can be monitored accurately using (55)Fe. Bacteria cells are incubated in the presence of either PVD or PCH loaded with (55)Fe. After incubation, extracellular iron ions are separated from those accumulated in the bacteria cells by either centrifugation or filtration on glass microfiber filters, for the PCH and PVD assays, respectively. (55)Fe contained in the harvested cells on the filter or in the cell pellet is counted in scintillation cocktail. The number of moles of (55)Fe transported can be determined using the specific activity of the radionuclide. PMID:24818918

  16. Lysimeter study of vegetative uptake from saltstone

    SciTech Connect

    Murphy, C.E. Jr.

    1990-06-08

    At the Savannah River Site, liquid, low-level nuclear waste will be disposed of by incorporating the waste in concrete, a wasteform called saltstone. Saltstone monoliths will then be buried in the earth. To study the potential uptake of radionuclides by trees and other plants growing in the soil in the area containing buried saltstone, a lysimeter study has been in progress since 1984. Thirty two lysimeters were designed, constructed, and filled with soil. Saltstone samples, containing the liquid, low-level supernate from the tank 50 in-tank precipitation demonstration, were buried in some of the lysimeters. Other lysimeters, not containing saltstone, were used as controls. Crops, grass, and trees were planted in the lysimeters and sampled periodically to determine radionuclide concentrations. Water samples were also collected from the lysimeter sumps and analyzed for radionuclide content. This report documents the results of vegetative and lysimeter sump water measurements from the beginning of the project in November of 1984 through September of 1989. 6 refs., 22 figs., 6 tabs.

  17. Uptake, Distribution and Speciation of Chromium

    SciTech Connect

    Bluskov,S.; Arocena, J.; Omotoso, O.; Young, J.

    2005-01-01

    Brassica juncea (Indian mustard) has been widely used in phytoremediation because of its capacity to accumulate high levels of chromium (Cr) and other metals. The present study was conducted to investigate mechanism(s) involved in Cr binding and sequestration by B. juncea. The plants were grown under greenhouse conditions in field-moist or air-dried soils, amended with 100 mg kg -1 of Cr (III or VI). The plant concentrated Cr mainly in the roots. B. juncea removed an average of 48 and 58 {mu}g Cr per plant from Cr (III) and Cr (VI)-treated soils, respectively. The uptake of Cr was not affected by the moisture status of the soils. X-ray absorption near-edge spectroscopy measurements showed only Cr (III) bound predominantly to formate and acetate ligands, in the bulk and rhizosphere soils, respectively. In the plant tissues, Cr (III) was detected, primarily as acetate in the roots and oxalate in the leaves. X-ray microprobe showed the sites of Cr localization, and probably sequestration, in epidermal and cortical cells in the roots and epidermal and spongy mesophyll cells in the leaves. These findings demonstrate the ability of B. juncea to detoxify more toxic Cr (VI), thereby making this plant a potential candidate for phytostabilization.

  18. Physiology, morphology, and ozone uptake of leaves of black cherry seedlings, saplings, and canopy trees.

    PubMed

    Fredericksen, T S; Joyce, B J; Skelly, J M; Steiner, K C; Kolb, T E; Kouterick, K B; Savage, J E; Snyder, K R

    1995-01-01

    Patterns of ozone uptake were related to physiological, morphological, and phenological characteristics of different-sized black cherry trees (Prunus serotina Ehrh.) at a site in central Pennsylvania. Calculated ozone uptake differed among open-grown seedlings, forest gap saplings, and canopy trees and between leaves in the upper and lower crown of saplings and canopy trees. On an instantaneous basis, seedling leaves had the greatest ozone uptake rates of all tree size classes due to greater stomatal conductance and higher concentrations of ozone in their local environment. A pattern of higher stomatal conductance of seedlings was consistent with higher incident photosynthetically-active radiation, stomatal density, and predawn xylem water potentials for seedlings relative to larger trees. However, seedlings displayed an indeterminate pattern of shoot growth, with the majority of their leaves produced after shoot growth had ceased for canopy and sapling trees. Full leaf expansion occurred by mid-June for sapling and canopy trees. Because many of their leaves were exposed to ozone for only part of the growing season, seedlings had a lower relative exposure over the course of the growing season, and subsequently lower cumulative uptake, of ozone than canopy trees and a level of uptake similar to upper canopy leaves of saplings. Visible injury symptoms were not always correlated with patterns in ozone uptake. Visible symptoms were more apparent on seedling leaves in concurrence with their high instantaneous uptake rates. However, visible injury was more prevalent on leaves in the lower versus upper crown of canopy trees and saplings, even though lower crown leaves had less ozone uptake. Lower crown leaves may be more sensitive to ozone per unit uptake than upper crown leaves because of their morphology. In addition, the lower net carbon uptake of lower crown leaves may limit repair and anti-oxidant defense processes. PMID:15091517

  19. Riboflavin uptake by the human-derived liver cells Hep G2: mechanism and regulation.

    PubMed

    Said, H M; Ortiz, A; Ma, T Y; McCloud, E

    1998-09-01

    The water-soluble vitamin riboflavin (RF) plays a critical role in many metabolic reactions, and thus, is essential for normal cellular functions and growth. The liver plays a central role in normal RF metabolism and is the site of maximal utilization of the vitamin. The mechanism of liver uptake of RF has been studied in animals, but no information is available describing the mechanism of the vitamin uptake in the human situation and its cellular regulation. In this study, we used the human-derived liver cells Hep G2 as an in vitro model system to address these issues. Uptake of RF by Hep G2 cells was found to be temperature- and energy-dependent but Na+-independent in nature. Uptake seemed to involve a carrier-mediated process as indicated by the saturation as a function of substrate concentration (apparent Km 0.41 +/- 0.08 microM), and by the ability of the structural analogs lumiflavin and lumichrome to inhibit the uptake process [inhibition constant (K) of 1.84 and 6.32 microM, respectively]. RF uptake was energy dependent, and was inhibited by the -SH group blocker p-chloromercuriphenylsulfonate (p-CMPS) (Ki of 0.10 mM). Specific modulators of intracellular protein kinase A (PKA)-, protein kinase C (PKC)-, and protein tyrosine kinase (PTK)-mediated pathways did not affect RF uptake by Hep G2 cells. On the other hand, specific inhibitors of Ca2+/calmodulin-mediated pathway significantly inhibited the uptake process; this effect seemed to be mediated through a decrease in the Vmax of the substrate uptake process. Maintaining Hep G2 cells in a RF-deficient growth medium was associated with a significant up-regulation in the substrate uptake; this effect was specific for RF and was mediated mainly by means of an increase in the Vmax of the uptake process. These results describe, for the first time, the mechanism and cellular regulation of RF uptake by a human-derived liver cellular preparation, and shows the involvement of a carrier-mediated system in the uptake

  20. Effect of Uptake-one inhibitors on the uptake of norepinephrine and metaiodobenzylguanidine

    SciTech Connect

    Tobes, M.C.; Jaques, S. Jr.; Wieland, D.M.; Sisson, J.C.

    1985-08-01

    The mechanisms underlying the uptake of the radiopharmaceutical metaiodobenzylguanidine (MIBG) and the catecholamine norepinephrine (NE) were studied using cultured bovine adrenomedullary cells as an in vitro model system. Sodium-dependent and sodium-independent uptake systems have been identified and characterized for both MIBG and NE. The sodium-dependent uptake of Ne and MIBG was inhibited by the selective Uptake-one inhibitors, desmethylimipramine (DMI) and cocaine, whereas the sodium-independent uptake for NE and MIBG was much less sensitive to inhibition by these agents. The sodium-dependent uptake system fulfills the criteria for the neuronal Uptake-one system, and the sodium-independent uptake system fulfills the criteria for a passive diffusion mechanism. Arterial concentrations proximal to the dog adrenal were very small suggesting that the sodium-dependent (Uptake-one) system is predominant in vivo. Consistent with the in vitro observations, the in vivo uptake of MIBG and NE into dog adrenal medullae was effectively blocked by pretreatment with DMI or cocaine. Therefore, iodine-131 MIBG scintigraphy of the adrenal appears to reflect uptake by way of the Uptake-one system.

  1. Corrective Feedback and Learner Uptake in CALL

    ERIC Educational Resources Information Center

    Heift, Trude

    2004-01-01

    This paper describes a study in which we investigated the effects of corrective feedback on learner uptake in CALL. Learner uptake is here defined as learner responses to corrective feedback in which, in case of an error, students attempt to correct their mistake(s). 177 students from three Canadian universities participated in the study during…

  2. Incidental fleurodeoxyglucose uptake in the prostate

    PubMed Central

    Wong, W L; Moule, R N; Nunan, T

    2010-01-01

    This commentary confirms the rarity of prostatic cancer associated with incidental prostatic fleurodeoxyglucose (FDG) uptake. The study adds to the literature by showing that even if a prostate lesion is FDG avid it is unlikely to be due to cancer. The commentary considers the management of incidental prostate FDG uptake on the basis of the available evidence. PMID:20965899

  3. Gallium-67 pulmonary uptake in eosinophilic pneumonia

    SciTech Connect

    Morais, J.; Carrier, L.; Gariepy, G.; Le Bel, L.; Chartrand, R.; Picard, D.

    1988-01-01

    Eosinophilic pneumonia is usually diagnosed based on the findings on chest x-ray, white blood count, and transbronchial biopsy. After reporting a case of Ga-67 lung uptake in eosinophilic pneumonia, its histopathology is discussed and the mechanisms of Ga-67 uptake by inflammatory lesions are reviewed.

  4. Cellular uptake of neutral phosphorodiamidate morpholino oligomers.

    PubMed

    Iversen, Patrick L; Aird, Katherine M; Wu, Rebecca; Morse, Michael M; Devi, Gayathri R

    2009-09-01

    Phosphorodiamidate morpholino oligomers (PMO), which have a neutral chemistry, are extensively being used as tools for selective inhibition of gene expression in cell culture models and are currently in human clinical trials. Unlike phosphorothioates (PS ODN) and other charged oligonucleotides, little is known about the uptake characteristics of neutral oligomers. The purpose of this study was to understand the kinetics of PMO transport in cells and correlate with antisense activity. In contrast to primary cells and some transformed cell lines which were uptake permissive, established cancer cell lines showed very poor uptake with an occasional diffuse intracellular pattern. Differential PMO uptake was also observed in immune cells, with dendritic cells and monocytes showing highest uptake compared to T and B cells. In addition, PMO localization was observed to be heterogeneous within a population of uptake permissive cells. Unassisted PMO delivery targeting specific genes was correlated with functional antisense efficacy in experiments showing correction of pre-mRNA missplicing and inhibition of target enzyme activity in cells in culture. PMO internalization in uptake-permissive cells was identified to be specific, saturable, and energy-dependent, suggesting a receptor mediated uptake mechanism. Understanding PMO transport should facilitate the design of more effective synthetic antisense oligomers as therapeutic agents.

  5. Glucose metabolism in sediments of a eutrophic lake: tracer analysis of uptake and product formation.

    PubMed

    King, G M; Klug, M J

    1982-12-01

    The uptake of glucose and the formation of end products from glucose catabolism have been measured for sediments of eutrophic Wintergreen Lake with a combination of tritiated and C-labeled tracers. Time course analyses of the loss of [H]glucose from sediments were used to establish rate constants for glucose uptake at natural substrate concentrations. Turnover times from these analyses were about 1 min for littoral and profundal sediments. No seasonal or site differences were noted in turnover times. Time course analyses of [U-C]glucose uptake and C-labeled end product formation indicated that glucose mass flow could not be calculated from end product formation since the specific activity of added [C]glucose was significantly diluted by pools of intracellular glucose and glucose metabolites. Mass flow could only be accurately estimated by use of rates of uptake from tracer studies. Intermediate fermentation end products included acetate (71%), propionate (15%), lactate (9%), and only minor amounts of butyrates or valerates. Addition of H(2) to sediments resulted in greater production of lactate (28%) and decreased formation of acetate (50%), but did not affect glucose turnover. Depth profiles of glucose uptake indicated that rates of uptake decreased with depth over the 0- to 18-cm interval and that glucose uptake accounted for 30 to 40% of methanogenesis in profundal sediments.

  6. Sorptive uptake of selenium with magnetite and its supported materials onto activated carbon.

    PubMed

    Kwon, Jae H; Wilson, Lee D; Sammynaiken, R

    2015-11-01

    Kinetic and equilibrium uptake studies of selenite in aqueous solution with synthetic magnetite (Mag-P), commercial magnetite (Mag-C), goethite, activated carbon (AC), and a composite material containing 19% magnetite supported on activated carbon (CM-19) were investigated. Kinetic uptake studies used a one-pot setup at pH 5.26 at variable temperature. Sampling of unbound selenite in-situ was achieved with analytical detection by atomic absorbance. The sorptive uptake at equilibrium and kinetic conditions are listed in descending order: goethite>Mag-P>Mag-C>CM-19. Kinetic uptake parameters reveal that Mag-P showed apparent negative values for the activation energy (E(a)) and the enthalpy of activation (ΔH(‡)), in agreement with a multi-step process for the kinetic uptake of selenite. By contrast, Mag-C, CM-19, and goethite showed positive values for E(a) and ΔH(‡). The uptake properties of the various sorbent materials with selenite are in accordance with the formation of inner- and out-sphere complexes. Leaching of iron from the composite material (CM-19) was attenuated due to the stabilizing effect of the magnetite within the pore sites and the surface of AC. Supported iron oxide nanomaterial composites represent a unique sorbent material with tunable uptake properties toward inorganic selenite in aqueous solution.

  7. Electrogenicity of hepatocellular fatty acid uptake.

    PubMed

    Elsing, C; Kassner, A; Gajdzik, L; Graf, J; Stremmel, W

    1998-08-18

    Sensitivity of cellular fatty acids uptake to the membrane potential difference is still a matter of controversy. For direct evaluation of potential sensitivity the effect of changing membrane potential on uptake of a fluorescent long chain fatty acid derivative, 12-NBD-stearate, in isolated rat hepatocytes, was examined. Changes in membrane potential were achieved by patch clamp procedures. Fatty acid influx was simultaneously determined by recording of cell fluorescence. Hyperpolarization from -30 to -70 mV accelerated fatty acid influx whereas depolarization to +50 mV reduced uptake. After obtaining equilibrium hyperpolarization increased cell fluorescence, whereas depolarization pushed NBD-stearate out of cells. Potential sensitivity of uptake was dependent on the fatty acid concentrations in the medium with most prominent effects at low unbound concentrations. These data show that, at low fatty acid concentrations, uptake is, in part, driven by an intracellular negative electric membrane potential.

  8. Highly infectious symbiont dominates initial uptake in coral juveniles.

    PubMed

    Abrego, David; VAN Oppen, Madeleine J H; Willis, Bette L

    2009-08-01

    The majority of reef-building corals acquire their obligate algal symbionts (Symbiodinium) from the environment. However, factors shaping the initial establishment of coral-algal symbioses, including parental effects, local environmental conditions and local availability of symbionts, are not well understood. This study monitored the uptake and maintenance of Symbiodinium in juveniles of two common corals, Acropora tenuis and Acropora millepora, that were reciprocally explanted between sites where adult colonies host different types of Symbiodinium. We found that coral juveniles were rapidly dominated by type D Symbiodinium, even though this type is not found in adult colonies (including the parental colonies) in four out of the five study populations. Furthermore, type D Symbiodinium was found in less than one-third of a wide range of coral species (n > 50) sampled at the two main study sites, suggesting that its dominance in the acroporid juveniles is not because it is the most abundant local endosymbiotic type. Moreover, dominance by type D was observed irrespective of the light intensity to which juveniles were exposed in a field study. In summary, despite its relatively low abundance in coral assemblages at the study sites and irrespective of the surrounding light environment, type D Symbiodinium is the main symbiont type initially acquired by juveniles of A. millepora and A. tenuis. We conclude that during early ontogeny in these corals, there are few barriers to the uptake of Symbiodinium types which differ from those found in parental colonies, resulting in dominance by a highly infectious and potentially opportunistic symbiont.

  9. Controls on tree water uptake and information storage in tree rings

    NASA Astrophysics Data System (ADS)

    Blume, Theresa; Simard, Sonia; Heidbüchel, Ingo; Güntner, Andreas; Heinrich, Ingo

    2016-04-01

    Controls on tree water uptake are investigated in various forest stands in the northeastern German lowlands by a multi-method approach. This approach combines sapflow and dendrometer measurements as well as tree-ring analyses with soil moisture derived root water uptake rates. The latter method has the advantage that it provides depth distributions of root water uptake and thus additional information allowing for a more detailed analysis of the relationship between water availability and water uptake. High resolution climatic data makes it possible to investigate the site specific interplay between atmospheric demand and water availability on the one hand and tree response and adaptation on the other hand. The comparison of spatio-temporal patterns of these responses with concurrent tree growth as well as tree-ring analyses enables a first matching of actual and "archived" patterns and thus an estimate of how much of this information is stored in tree rings.

  10. Phytoplankton productivity, respiration, and nutrient uptake and regeneration in the Potomac River, August 1977 - August 1978

    USGS Publications Warehouse

    Cole, B.E.; Harmon, D.D.

    1981-01-01

    Rates of phytoplankton productivity, respiration, and nutrient uptake and regeneration are presented. These observations were made on the Potomac River estuary (POTE) during four cruises between August 1977 and August 1978. Four experimental methods were used: carbon uptake using carbon-14, carbon uptake and respiration by a pH method, productivity and respiration by the dissolved oxygen method, and nutrient (NH4+, NO3-, NO2-, PO4=, and SiO2=) uptake and regeneration by colorimetry. The experiments were made at sites representative of conditions in four principal reaches of the tidal Potomac River estuary: near the mouth, seaward of the summer nutrient and phytoplankton maximum, near the region of maximum phytoplankton standing stock , and near the maximum anthropogenic nutrient source. (USGS)

  11. Cadmium and calcium uptake in the mollusc donax rugosus and effect of a calcium channel blocker

    SciTech Connect

    Sidoumou, Z.; Gnassia-Barelli, M.; Romeo, M.

    1997-02-01

    Donax rugosus, a common bivalve mollusc in the coastal waters of Mauritania, has been studied for trace metal concentrations as a function of sampling site (from South of Mauritania to the North of this country) and of season. In this paper, the uptake of cadmium was experimentally studied in the different organs of D. rugosus. Since metals such as cadmium, copper and mercury may alter calcium homeostasis, calcium uptake was also studied in the animals treated with cadmium. Since calcium is taken up through specific channels, it appears that metals inhibit Ca uptake by interacting with these channels in the plasma membrane. Cadmium and calcium have very similar atomic radii, thus cadmium may be taken up through the calcium channels, particularly through voltage-dependent channels. The uptake of cadmium and calcium by D. Rugosus was therefore also studied in the presence of the calcium channel blocker verapamil. 13 refs., 3 figs., 1 tab.

  12. Technetium-99m-HDP uptake characteristics in equine fractures: a retrospective study.

    PubMed

    Scheidegger, E; Geissbühlerl, U; Doherr, M G; Lang, J

    2006-10-01

    Bone scintigraphy is a very sensitive diagnostic tool to detect elevated bone metabolism. In cases of fractures and fissure fractures, the radiopharmaceutical uptake in the bone is said to be increased within a few hours after the injury. In this retrospective study, the scintigraphic uptake characteristics at the fracture site of 36 horses with radiographically confirmed fractures or fissure fractures were evaluated. Uptake ratios between the fracture region and adjacent normal bone or soft tissue activity respectively were calculated and compared to different anamnestic and radiographic data. The overall sensitivity of bone scintigraphy was 94.4% (34 positive cases out of 36). In the 36 horses, no correlation between the age of the fracture and the radiopharmaceutical uptake was found. However, there seems to be a lack of sensitivity in early detection of equine pelvic fractures when a standing bone scintigraphy examination protocol is used.

  13. Modification of nitrate uptake pathway in plants affects the cadmium uptake by roots.

    PubMed

    Guan, Mei Yan; Fan, Shi Kai; Fang, Xian Zhi; Jin, Chong Wei

    2015-01-01

    NRT1.1 is a dual-affinity nitrate (NO3(-)) transporter involved in both high- and low-affinity NO3(-) uptake in Arabidopsis plants. In a recent study, we showed that, under cadmium (Cd) exposure, blocking the NRT1.1-mediated NO3(-) uptake reduces Cd entry into roots, thus lowing Cd levels in plants and improving plant growth. In addition, we also found that the Cd levels in edible parts of 11 Chinese cabbage (Brassica rapa L. ssp. pekinensis) cultivars correlated well with the NO3(-) uptake rates of their roots. These results suggested that the NO3(-) uptake of roots negatively regulate Cd uptake. Modification of NO3(-) uptake in crops by modulating NO3(-) uptake pathway might provide a biological engineering approach to reducing Cd accumulation in edible organs, thus improving food safety.

  14. Plant-uptake of uranium: Hydroponic and soil system studies

    USGS Publications Warehouse

    Ramaswami, A.; Carr, P.; Burkhardt, M.

    2001-01-01

    Limited information is available on screening and selection of terrestrial plants for uptake and translocation of uranium from soil. This article evaluates the removal of uranium from water and soil by selected plants, comparing plant performance in hydroponic systems with that in two soil systems (a sandy-loam soil and an organic-rich soil). Plants selected for this study were Sunflower (Helianthus giganteus), Spring Vetch (Vicia sativa), Hairy Vetch (Vicia villosa), Juniper (Juniperus monosperma), Indian Mustard (Brassica juncea), and Bush Bean (Phaseolus nanus). Plant performance was evaluated both in terms of the percent uranium extracted from the three systems, as well as the biological absorption coefficient (BAC) that normalized uranium uptake to plant biomass. Study results indicate that uranium extraction efficiency decreased sharply across hydroponic, sandy and organic soil systems, indicating that soil organic matter sequestered uranium, rendering it largely unavailable for plant uptake. These results indicate that site-specific soils must be used to screen plants for uranium extraction capability; plant behavior in hydroponic systems does not correlate well with that in soil systems. One plant species, Juniper, exhibited consistent uranium extraction efficiencies and BACs in both sandy and organic soils, suggesting unique uranium extraction capabilities.

  15. The uptake of water hardness metals by human hair.

    PubMed

    Evans, A O; Marsh, J M; Wickett, R R

    2011-01-01

    The objective of this work was to examine the variables that influence the interaction between water hardness metals and human hair. Hair extracts various constituents from the tap water used during daily hygiene practices and chemical treatments. Calcium and magnesium metal ions are the most prevalent and give water "hardness." Inductively coupled plasma atomic emission spectroscopy (ICP-AES) was employed to quantify the metal content of hair, which was studied as a function of the following variables: hair condition (oxidative damage), level of water hardness, and water pH. We have demonstrated that these variables impact water hardness metal uptake to varying extents, and the effects are driven primarily by the binding capacity (available anionic sites) of the hair. The condition of the hair, a key representation of the binding capacity, was most influential. Interestingly, water hardness levels had only a small effect on uptake; hair became saturated with notable amounts of water hardness metals even after repeated exposure to soft water. Water pH influenced metal uptake since side chains of hair proteins deprotonate with increasing alkalinity. These insights highlight the importance to the hair care industry of understanding the interaction between water hardness metals and hair.

  16. Cystine and dibasic amino acid uptake by opossum kidney cells

    SciTech Connect

    States, B.; Segal, S. )

    1990-06-01

    The characteristics of the uptake of L-cystine by the continuous opossum kidney cell line, OK, were examined. Uptake of cystine is rapid and, in contrast to other continuous cultured cell lines, these cells retain the cystine/dibasic amino acid transport system which is found in vivo and in freshly isolated kidney tissue. Confluent monolayers of cells also fail to show the presence of the cystine/glutamate transport system present in LLC-PK1 cells, fibroblasts, and cultured hepatocytes. Uptake of cystine occurs via a high-affinity saturable process which is independent of medium sodium concentration. The predominant site of cystine transport is across the apical cell membrane. The intracellular concentration of GSH far exceeds that of cystine with a ratio greater than 100:1 for GSH:cysteine. Incubation of cells for 5 minutes with a physiological level of labelled cystine resulted in the labelling of 66% and 5% of the total intracellular cysteine and glutathione, respectively. The ability of these cells to reflect the shared cystine/dibasic amino acid transport system makes them a suitable model for investigation of the cystine carrier which is altered in human cystinuria.

  17. Radiostrontium uptake by plants from different soil types in Kazakhstan.

    PubMed

    Savinkov, A; Semioshkina, N; Howard, B J; Voigt, G

    2007-02-01

    The transfer of 90Sr to a range of different plant species grown on a range of different soil types in Kazakhstan, including three from the Semipalatinsk Test Site (STS), has been measured in a lysimeter experiment. 90Sr uptake by Stipa spp was significantly higher than for other vegetation species. The uptake of 90Sr from chernozem was significantly lower than that from the other soil types which is consistent with other literature. There was a significant negative relationship between 90Sr uptake and calcium, humus and CEC concentration in the soil for Agropyrum spp, Artemisia spp but not for Stipa spp or Bromus spp. The transfer to vegetation from soil has been quantified using the aggregated transfer coefficients for each species. Tag values range from 0.6 to 11.9 m2 kg-1x10(-3) over all measurements. The transfer of 90Sr to plants from the Kazakh soils was low compared to previously reported data and to that given from literature reviews.

  18. Temperature responses of carbon monoxide and hydrogen uptake by vegetated and unvegetated volcanic cinders

    PubMed Central

    King, Caitlin E; King, Gary M

    2012-01-01

    Ecosystem succession on a large deposit of volcanic cinders emplaced on Kilauea Volcano in 1959 has resulted in a mosaic of closed-canopy forested patches and contiguous unvegetated patches. Unvegetated and unshaded surface cinders (Bare) experience substantial diurnal temperature oscillations ranging from moderate (16 °C) to extreme (55 °C) conditions. The surface material of adjacent vegetated patches (Canopy) experiences much smaller fluctuations (14–25 °C) due to shading. To determine whether surface material from these sites showed adaptations by carbon monoxide (CO) and hydrogen (H2) consumption to changes in ambient temperature regimes accompanying succession, we measured responses of CO and H2 uptake to short-term variations in temperature and long-term incubations at elevated temperature. Based on its broader temperature optimum and lower activation energy, Canopy H2 uptake was less sensitive than Bare H2 uptake to temperature changes. In contrast, Bare and Canopy CO uptake responded similarly to temperature during short-term incubations, indicating no differences in temperature sensitivity. However, during extended incubations at 55 °C, CO uptake increased for Canopy but not Bare material, which indicated that the former was capable of thermal adaptation. H2 uptake for material from both sites was completely inhibited at 55 °C throughout extended incubations. These results indicated that plant development during succession did not elicit differences in short-term temperature responses for Bare and Canopy CO uptake, in spite of previously reported differences in CO oxidizer community composition, and differences in average daily and extreme temperatures. Differences associated with vegetation due to succession did, however, lead to a notable capacity for thermophilic CO uptake by Canopy but not Bare material. PMID:22258097

  19. Variable effects of plant colonization on black slate uptake into microbial PLFAs

    NASA Astrophysics Data System (ADS)

    Seifert, Anne-Gret; Trumbore, Susan; Xu, Xiaomei; Zhang, Dachung; Gleixner, Gerd

    2013-04-01

    Microbial degradation of carbon derived from black shale and slate has been shown in vitro. However, in natural settings where other labile carbon sources are likely to exist, this has not been previously demonstrated. We investigated the uptake of ancient carbon derived from slate weathering and from recently photosynthesised organic matter by different groups of microorganisms. Therefore we isolated microbial biomarkers (phospholipid fatty acids, PLFAs) from black slates collected at a chronosequence of waste piles which differed in age and vegetation cover. We quantified the amount of PLFAs and performed stable isotope and radiocarbon measurements on individual or grouped PLFAs to quantify the fraction of slate derived carbon. We used black slate from a pile heaped in the 1950s with either uncovered black slate material (bare site) or material slightly colonized by small plants (greened site) and from a forested leaching pile (forested site) used for alum-mining in the 19th century. Colonization by plants influenced the amount and composition of the microbial community. Greater amounts of PLFAs (5410 ng PLFA/g dw) were extracted from slate sampled at the forested site as opposed to the bare site (960 ng PLFAs/g dw) or the greened (annual grasses and mosses) rock waste pile (1050 ng PLFAs/g dw). We found the highest proportion of PLFAs representing Gram-negative bacteria on the forested site and the highest proportion of PLFAs representing Gram-positive bacteria on the bare site. The fungal PLFA was most abundant at the greened site. Sites with less plant colonization (bare and greened site) tended to have more depleted δ13C values compared to the forested site. Radiocarbon measurements on PLFAs indicated that fungi and Gram-positive bacteria were best adapted to black slate carbon uptake. In the fungal PLFA (combined bare and greened waste pile sample) and in PLFAs of Gram-positive bacteria (greened site) we measured 39.7% and 28.9% ancient carbon uptake

  20. A statistical approach to estimate O3 uptake of ponderosa pine in a mediterranean climate.

    PubMed

    Grulke, N E; Preisler, H K; Fan, C C; Retzlaff, W A

    2002-01-01

    In highly polluted sites, stomatal behavior is sluggish with respect to light, vapor pressure deficit, and internal CO2 concentration (Ci) and poorly described by existing models. Statistical models were developed to estimate stomatal conductance (gs) of 40-year-old ponderosa pine at three sites differing in pollutant exposure for the purpose of calculating O3 uptake. Gs was estimated using julian day, hour of day, pre-dawn xylem potential and photosynthetic photon flux density (PPFD). The median difference between estimated and observed field gs did not exceed 10 mmol H2O m(-2) s(-1), and estimated gs within 95% confidence intervals. 03 uptake was calculated from hourly estimated gs, hourly O3 concentration, and a constant to correct for the difference in diffusivity between water vapor and 03. The simulation model TREGRO was also used to calculate the cumulative 03 uptake at all three sites. 03 uptake estimated by the statistical model was higher than that simulated by TREGRO because gas exchange rates were proportionally higher. O3 exposure and uptake were significantly correlated (r2>0.92), because O3 exposure and gs were highly correlated in both statistical and simulation models. PMID:12152824

  1. Uptake of perchlorate in terrestrial plants.

    PubMed

    Yu, Lu; Cañas, Jaclyn E; Cobb, George P; Jackson, William A; Anderson, Todd A

    2004-05-01

    Cucumber (Cucumis sativus L.), lettuce (Lactuca sativa L.), and soybean (Glycine max) were used to determine uptake of the perchlorate anion (100 ppb) from sand. Plants were watered with different ratios of Hydrosol (a diluted solution of Peters All-Purpose Plant Food) to Milli-Q water (18 MOmega) to determine if the presence of other nutrients (such as nitrate) influenced perchlorate uptake. Perchlorate concentrations in sand and plant tissues were determined weekly. Perchlorate uptake was observed in all three plant species. In most experiments, perchlorate was completely depleted from sand in which plants were growing. Perchlorate concentrations in lettuce were also significantly higher than those in cucumber and soybean (P < 0.0001). Perchlorate concentrations in sand decreased at a higher rate at lower ratios of Hydrosol to Milli-Q, indicating that plant (cucumber) uptake of perchlorate is influenced by the presence of external nutrients. The results of an 8-week uptake study in cucumber and a 6-week uptake study in lettuce suggest that a threshold perchlorate concentration is reached: for cucumber, 150 ppm and for lettuce, 750 ppm. Although the presence of external nutrients decreases the rate of perchlorate uptake by plants, significant concentrations of perchlorate occur in aboveground plant tissues even after relatively short periods of growth. The potential for trophic transfer of perchlorate from soil to higher organisms through plants exists.

  2. FDG uptake, a surrogate of tumour hypoxia?

    PubMed Central

    Van de Wiele, Christophe

    2008-01-01

    Introduction Tumour hyperglycolysis is driven by activation of hypoxia-inducible factor-1 (HIF-1) through tumour hypoxia. Accordingly, the degree of 2-fluro-2-deoxy-d-glucose (FDG) uptake by tumours might indirectly reflect the level of hypoxia, obviating the need for more specific radiopharmaceuticals for hypoxia imaging. Discussion In this paper, available data on the relationship between hypoxia and FDG uptake by tumour tissue in vitro and in vivo are reviewed. In pre-clinical in vitro studies, acute hypoxia was consistently shown to increase FDG uptake by normal and tumour cells within a couple of hours after onset with mobilisation or modification of glucose transporters optimising glucose uptake, followed by a delayed response with increased rates of transcription of GLUT mRNA. In pre-clinical imaging studies on chronic hypoxia that compared FDG uptake by tumours grown in rat or mice to uptake by FMISO, the pattern of normoxic and hypoxic regions within the human tumour xenografts, as imaged by FMISO, largely correlated with glucose metabolism although minor locoregional differences could not be excluded. In the clinical setting, data are limited and discordant. Conclusion Further evaluation of FDG uptake by various tumour types in relation to intrinsic and bioreductive markers of hypoxia and response to radiotherapy or hypoxia-dependent drugs is needed to fully assess its application as a marker of hypoxia in the clinical setting. PMID:18509637

  3. Does elevated CO2 alter silica uptake in trees?

    PubMed

    Fulweiler, Robinson W; Maguire, Timothy J; Carey, Joanna C; Finzi, Adrien C

    2014-01-01

    Human activities have greatly altered global carbon (C) and Nitrogen (N) cycling. In fact, atmospheric concentrations of carbon dioxide (CO2) have increased 40% over the last century and the amount of N cycling in the biosphere has more than doubled. In an effort to understand how plants will respond to continued global CO2 fertilization, long-term free-air CO2 enrichment experiments have been conducted at sites around the globe. Here we examine how atmospheric CO2 enrichment and N fertilization affects the uptake of silicon (Si) in the Duke Forest, North Carolina, a stand dominated by Pinus taeda (loblolly pine), and five hardwood species. Specifically, we measured foliar biogenic silica concentrations in five deciduous and one coniferous species across three treatments: CO2 enrichment, N enrichment, and N and CO2 enrichment. We found no consistent trends in foliar Si concentration under elevated CO2, N fertilization, or combined elevated CO2 and N fertilization. However, two-thirds of the tree species studied here have Si foliar concentrations greater than well-known Si accumulators, such as grasses. Based on net primary production values and aboveground Si concentrations in these trees, we calculated forest Si uptake rates under control and elevated CO2 concentrations. Due largely to increased primary production, elevated CO2 enhanced the magnitude of Si uptake between 20 and 26%, likely intensifying the terrestrial silica pump. This uptake of Si by forests has important implications for Si export from terrestrial systems, with the potential to impact C sequestration and higher trophic levels in downstream ecosystems.

  4. Does elevated CO2 alter silica uptake in trees?

    DOE PAGESBeta

    Fulweiler, Robinson W.; Maguire, Timothy J.; Carey, Joanna C.; Finzi, Adrien C.

    2015-01-13

    Human activities have greatly altered global carbon (C) and Nitrogen (N) cycling. In fact, atmospheric concentrations of carbon dioxide (CO2) have increased 40% over the last century and the amount of N cycling in the biosphere has more than doubled. In an effort to understand how plants will respond to continued global CO2 fertilization, longterm free-air CO2 enrichment experiments have been conducted at sites around the globe. Here we examine how atmospheric CO2 enrichment and N fertilization affects the uptake of silicon (Si) in the Duke Forest, North Carolina, a stand dominated by Pinus taeda (loblolly pine), and five hardwoodmore » species. Specifically, we measured foliar biogenic silica concentrations in five deciduous and one coniferous species across three treatments: CO2 enrichment, N enrichment, and N and CO2 enrichment. We found no consistent trends in foliar Si concentration under elevated CO2, N fertilization, or combined elevated CO2 and N fertilization. However, two-thirds of the tree species studied here have Si foliar concentrations greater than well-known Si accumulators, such as grasses. Based on net primary production values and aboveground Si concentrations in these trees, we calculated forest Si uptake rates under control and elevated CO2 concentrations. Due largely to increased primary production, elevated CO2 enhanced the magnitude of Si uptake between 20 and 26%, likely intensifying the terrestrial silica pump. This uptake of Si by forests has important implications for Si export from terrestrial systems, with the potential to impact C sequestration and higher trophic levels in downstream ecosystems.« less

  5. Does elevated CO2 alter silica uptake in trees?

    PubMed Central

    Fulweiler, Robinson W.; Maguire, Timothy J.; Carey, Joanna C.; Finzi, Adrien C.

    2015-01-01

    Human activities have greatly altered global carbon (C) and Nitrogen (N) cycling. In fact, atmospheric concentrations of carbon dioxide (CO2) have increased 40% over the last century and the amount of N cycling in the biosphere has more than doubled. In an effort to understand how plants will respond to continued global CO2 fertilization, long-term free-air CO2 enrichment experiments have been conducted at sites around the globe. Here we examine how atmospheric CO2 enrichment and N fertilization affects the uptake of silicon (Si) in the Duke Forest, North Carolina, a stand dominated by Pinus taeda (loblolly pine), and five hardwood species. Specifically, we measured foliar biogenic silica concentrations in five deciduous and one coniferous species across three treatments: CO2 enrichment, N enrichment, and N and CO2 enrichment. We found no consistent trends in foliar Si concentration under elevated CO2, N fertilization, or combined elevated CO2 and N fertilization. However, two-thirds of the tree species studied here have Si foliar concentrations greater than well-known Si accumulators, such as grasses. Based on net primary production values and aboveground Si concentrations in these trees, we calculated forest Si uptake rates under control and elevated CO2 concentrations. Due largely to increased primary production, elevated CO2 enhanced the magnitude of Si uptake between 20 and 26%, likely intensifying the terrestrial silica pump. This uptake of Si by forests has important implications for Si export from terrestrial systems, with the potential to impact C sequestration and higher trophic levels in downstream ecosystems. PMID:25628636

  6. The K+/site and H+/site stoichiometry of mitochondrial electron transport.

    PubMed

    Reynafarje, B; Lehninger, A L

    1978-09-25

    Electrode measurements of the average number of H+ ejected and K+ taken up (in the presence of valinomycin) per pair of electrons passing the energy-conserving sites of the respiratory chain of rat liver and rat heart mitochondria have given identical values of the H+/site and 5+/site ratios very close to 4 in the presence of N-ethylmaleimide, an inhibitor of interfering respiration-coupled uptake of H+ + H2PO4-. The K+/site uptake ratio of 4 not only shows that inward movement of K+ provides quantitative charge-compensation for the 4 H+ ejected, but also confirms that 4 charges are separated per pair of electrons per site. When N-ethylmaleimide is omitted, the H+/site ejection ratio is depressed, because of the interfering secondary uptake of H/+ with H2PO4- on the phosphate carrier, but the K+/site uptake ratio remains at 4.0. Addition of phosphate or acetate, which can carry H+ into respiring mitochondria, further depresses the H+/site ratio, but does not affect the K+/site ratio, which remains at 4.0. These and other considerations thus confirm our earlier stoichiometric measurements that the average H+/site ratio is 4.0 and also show that the K+/site uptake ratio can be used as a measure of the intrinsic H+/site ratio, regardless of the presence of phosphate in the medium and without the necessity of adding N-ethylmaleimide or other inhibitors of H+ + H2PO4- transport.

  7. Uptake of fluorine-18-fluorodeoxyglucose in sarcoidosis

    SciTech Connect

    Lewis, P.J.; Salama, A.

    1994-10-01

    Whole-body PET scanning was performed using {sup 18}F-fluorodeoxyglucose (FDG) in two patients with hilar lymphadenopathy in whom the clinical differential diagnosis was between sarcoidosis and lymphoma. Both patients were later proven to have sarcoidosis. Uptake of {sup 18}FDG was seen in both intra- and extrathoracic lesions as well as in associated erythema nodosum. One patient underwent a repeat scan after steroid therapy where a marked decrease in hilar uptake was seen. Fluorine-18-fluorodeoxyglucose uptake is observed in lymph nodes with sarcoid involvement. Further investigation is necessary to assess if quantitative differences exist between sarcoid and malignant lymphadenopathy. 30 refs., 3 figs.

  8. Thermodynamic formalism of water uptakes on solid porous adsorbents for adsorption cooling applications

    SciTech Connect

    Sun, Baichuan; Chakraborty, Anutosh

    2014-05-19

    This Letter presents a thermodynamic formulation to calculate the amount of water vapor uptakes on various adsorbents such as zeolites, metal organic frameworks, and silica gel for the development of an advanced adsorption chiller. This formalism is developed from the rigor of the partition distribution function of each water vapor adsorptive site on adsorbents and the condensation approximation of adsorptive water molecules and is validated with experimental data. An interesting and useful finding has been established that the proposed model is thermodynamically connected with the pore structures of adsorbent materials, and the water vapor uptake highly depends on the isosteric heat of adsorption at zero surface coverage and the adsorptive sites of the adsorbent materials. Employing the proposed model, the thermodynamic trends of water vapor uptakes on various adsorbents can be estimated.

  9. Thermodynamic formalism of water uptakes on solid porous adsorbents for adsorption cooling applications

    NASA Astrophysics Data System (ADS)

    Sun, Baichuan; Chakraborty, Anutosh

    2014-05-01

    This Letter presents a thermodynamic formulation to calculate the amount of water vapor uptakes on various adsorbents such as zeolites, metal organic frameworks, and silica gel for the development of an advanced adsorption chiller. This formalism is developed from the rigor of the partition distribution function of each water vapor adsorptive site on adsorbents and the condensation approximation of adsorptive water molecules and is validated with experimental data. An interesting and useful finding has been established that the proposed model is thermodynamically connected with the pore structures of adsorbent materials, and the water vapor uptake highly depends on the isosteric heat of adsorption at zero surface coverage and the adsorptive sites of the adsorbent materials. Employing the proposed model, the thermodynamic trends of water vapor uptakes on various adsorbents can be estimated.

  10. Participation of 5-HT1-like and 5-HT2A receptors in the contraction of human temporal artery by 5-hydroxytryptamine and related drugs.

    PubMed Central

    Verheggen, R.; Freudenthaler, S.; Meyer-Dulheuer, F.; Kaumann, A. J.

    1996-01-01

    1. We investigated the hypothesis that, as in some other large human arteries, 5-HT-induced contraction of the temporal artery is mediated through two co-existing receptor populations, 5-HT1-like- and 5-HT2A. Temporal arterial segments were obtained from patients undergoing brain surgery and rings prepared set up to contract with 5-HT and related agents. Fractions of maximal 5-HT responses mediated through 5-HT1-like and 5-HT2A receptors, f1 and f2 = 1-f1, were estimated by use of the 5-HT2A-selective antagonist ketanserin. 2. In rings with intact endothelium 5-HT evoked contractions with a -log EC50, M of 7.0. Ketanserin (10-1000 nM) antagonized part of the 5-HT-induced contractions. Ketanserin-resistant components of 5-HT-induced contractions were found with -log EC50, M of 6.9 and f1 of 0.17 (100 nM ketanserin) and -log EC50, M of 6.4 and f1 of 0.20 (1000 nM ketanserin). 3. In rings with endothelial function attenuated by enzymatic treatment, 5-HT caused contractions with a -log EC50, M of 7.2 that were partially blocked by ketanserin. Ketanserin-resistant components of 5-HT-induced contractions were found with -log EC50, M 7.4 and f1 of 0.16 (100 nM ketanserin) and -log EC50, M of 7.5 and f1 of 0.14 (1000 nM ketanserin). 4. The ketanserin-resistant component of 5-HT-evoked contraction was blocked by methiothepin (100-1000 nM) consistent with mediation through 5-HT1-like receptors. 5. In rings with intact endothelium the 5-HT1-like-selective agonist, sumatriptan, caused small contractions with a -log EC50, M of 6.5 and intrinsic activity of 0.21 with respect to 5-HT that were resistant to blockade by 1000 nM ketanserin but antagonized by 100 nM methiothepin. 6. In rings with intact endothelium the 5-HT2A receptor partial agonist SK&F 103829 (2,3,4,5-tetrahydro-8[methyl sulphonyl]-1H3-benzazepin-7-ol methensulphonate) contracted rings with a -log EC50, M of 5.0 and an intrinsic activity of 0.49 with respect to 5-HT; the effects were antagonized by ketanserin 1000 nM. 7. We conclude that 80-86% of the maximum 5-HT-evoked contraction of human temporal artery is mediated through 5-HT2A receptors, the remainder through 5-HT1-like-receptors, regardless of whether or not endothelium is functional. The 5-HT1-like-receptors are more likely to be 5-HT1D beta receptors than 5-HT1D alpha receptors and sumatriptan is a full agonist for these receptors. As found in arteries of other species, SK&F 103829 is a partial agonist for 5-HT2A receptors of human temporal artery. PMID:8789380

  11. Development of Plate Reader and On-Line Microfluidic Screening to Identify Ligands of the 5-Hydroxytryptamine Binding Protein in Venoms.

    PubMed

    Otvos, Reka A; Iyer, Janaki Krishnamoorthy; van Elk, René; Ulens, Chris; Niessen, Wilfried M A; Somsen, Govert W; Kini, R Manjunatha; Smit, August B; Kool, Jeroen

    2015-07-01

    The 5-HT3 receptor is a ligand-gated ion channel, which is expressed in the nervous system. Its antagonists are used clinically for treatment of postoperative- and radiotherapy-induced emesis and irritable bowel syndrome. In order to better understand the structure and function of the 5-HT3 receptor, and to allow for compound screening at this receptor, recently a serotonin binding protein (5HTBP) was engineered with the Acetylcholine Binding Protein as template. In this study, a fluorescence enhancement assay for 5HTBP ligands was developed in plate-reader format and subsequently used in an on-line microfluidic format. Both assay types were validated using an existing radioligand binding assay. The on-line microfluidic assay was coupled to HPLC via a post-column split which allowed parallel coupling to a mass spectrometer to collect MS data. This high-resolution screening (HRS) system is well suitable for compound mixture analysis. As a proof of principle, the venoms of Dendroapsis polylepis, Pseudonaja affinis and Pseudonaja inframacula snakes were screened and the accurate masses of the found bioactives were established. To demonstrate the subsequent workflow towards structural identification of bioactive proteins and peptides, the partial amino acid sequence of one of the bioactives from the Pseudonaja affinis venom was determined using a bottom-up proteomics approach. PMID:26114334

  12. Application of the flow cytometry for determination of the amount of DNA in Yersinia pestis cells under the influence of serotonin (5-hydroxytryptamine)

    NASA Astrophysics Data System (ADS)

    Korsukov, Vladimir N.; Shchukovskaya, Tatyana N.; Kravtsov, Alexander L.; Popov, Youri A.

    2002-07-01

    Using flow cytometry a low DNA content in inoculated Yersinia pestis EV cells have been shown at the beginning of culture in Hottinger broth pH 7.2. The dependence serotonin action of its concentration on DNA content have been demonstrated. Serotonin accelerated Yersinia pestis culture growth during cultivation in Hottinger broth pH 7.2 both at 28 degrees C and 37 degrees C at concentration of 10-5 M.

  13. Modulatory Role of Postsynaptic 5-Hydroxytryptamine Type 1A Receptors in (±)-8-Hydroxy-N,N-dipropyl-2-aminotetralin-Induced Hyperphagia in Mice.

    PubMed

    Brosda, Jan; Müller, Nadine; Bert, Bettina; Fink, Heidrun

    2015-07-15

    Brain serotonin (5-HT) is involved in the control of food intake. The ingestive effects of 5-HT are mediated by various receptor subtypes, among others the 5-HT1A receptor. While the involvement of presynaptic 5-HT1A receptors is regarded as certain, the role of postsynaptic 5-HT1A receptors is rather vague. Here, we studied the role of the 5-HT1A receptor on feeding in non-food-deprived and food-deprived (young adult and adult, both sexes) wild-type NMRI mice as well as transgenic NMRI mice, which are characterized by a distinct overexpression of postsynaptic 5-HT1A receptors. The known hyperphagic effect of the 5-HT1A receptor full agonist 8-OH-DPAT ((±)-8-hydroxy-N,N-dipropyl-2-aminotetralin) in non-food-deprived animals was demonstrated in male NMRI wild-type mice and could be antagonized by the selective 5-HT1A receptor antagonist WAY100635. In transgenic mice, this hyperphagic response was induced at lower doses, with an earlier onset and even in females. However, in adult male transgenic mice, the hyperphagic effect did not occur. In food-deprived NMRI wild-type as well as transgenic mice, 8-OH-DPAT first induced a hypophagic and subsequently a hyperphagic effect. Again, in transgenic animals most responses occurred at lower doses and with an earlier onset. The results indicate that postsynaptic 5-HT1A receptors exert a modulatory function in food intake in free-feeding and fasted mice, which for the first time shows an involvement of postsynaptic 5-HT1A receptors in feeding behavior. Understanding the function of pre- and postsynaptic 5-HT1A receptors may help to achieve new insights into the regulation of food intake and foster prospective treatment strategies for eating disorders.

  14. Development of Plate Reader and On-Line Microfluidic Screening to Identify Ligands of the 5-Hydroxytryptamine Binding Protein in Venoms

    PubMed Central

    Otvos, Reka A.; Krishnamoorthy Iyer, Janaki; van Elk, René; Ulens, Chris; Niessen, Wilfried M. A.; Somsen, Govert W.; Kini, R. Manjunatha; Smit, August B.; Kool, Jeroen

    2015-01-01

    The 5-HT3 receptor is a ligand-gated ion channel, which is expressed in the nervous system. Its antagonists are used clinically for treatment of postoperative- and radiotherapy-induced emesis and irritable bowel syndrome. In order to better understand the structure and function of the 5-HT3 receptor, and to allow for compound screening at this receptor, recently a serotonin binding protein (5HTBP) was engineered with the Acetylcholine Binding Protein as template. In this study, a fluorescence enhancement assay for 5HTBP ligands was developed in plate-reader format and subsequently used in an on-line microfluidic format. Both assay types were validated using an existing radioligand binding assay. The on-line microfluidic assay was coupled to HPLC via a post-column split which allowed parallel coupling to a mass spectrometer to collect MS data. This high-resolution screening (HRS) system is well suitable for compound mixture analysis. As a proof of principle, the venoms of Dendroapsis polylepis, Pseudonaja affinis and Pseudonaja inframacula snakes were screened and the accurate masses of the found bioactives were established. To demonstrate the subsequent workflow towards structural identification of bioactive proteins and peptides, the partial amino acid sequence of one of the bioactives from the Pseudonaja affinis venom was determined using a bottom-up proteomics approach. PMID:26114334

  15. 5-hydroxytryptamine- and dopamine-releasing effects of ring-substituted amphetamines on rat brain: a comparative study using in vivo microdialysis.

    PubMed

    Matsumoto, T; Maeno, Y; Kato, H; Seko-Nakamura, Y; Monma-Ohtaki, J; Ishiba, A; Nagao, M; Aoki, Y

    2014-08-01

    Using in vivo microdialysis, a comparative study was conducted to examine the effects of amphetamine-related compounds (methamphetamine, MAP; 3,4-methylenedioxymethamphetamine, MDMA; p-methoxyamphetamine, PMA; p-methoxymethamphetamine, PMMA; 4-methylthioamphetamine, 4-MTA; 3,4,5-trimethoxyamphetamine, TMA; 2,5-dimethoxy-4-iodoamphetamine, DOI) on extracellular levels of serotonin (5-HT) and dopamine (DA). Dialysates were assayed using HPLC equipped with electrochemical detector following i.p. administration with each drug at a dose of 5 mg/kg. MAP was found to drastically and rapidly increase 5-HT and DA levels (870% and 1460%, respectively). PMA, PMMA, and 4-MTA slightly increased DA levels (150-290%) but remarkably increased 5-HT levels (540-900%). In contrast, TMA and DOI caused no detectable changes in levels of both monoamines. We observed that the potent DA-releasing action of MAP was remarkably decreased by introduction of methoxy or methylthio group at the para position (MAP vs. PMMA or 4-MTA), but introduction of two additional adjacent methoxy groups into PMA totally abolished its 5-HT-/DA-releasing action (PMA vs. TMA). In addition, para-mono-substituted compounds inhibited both monoamine oxidase (MAO) enzymes more strongly than other compounds; PMA and 4-MTA exhibited submicromolar IC50 values for MAO-A. On the other hand, TMA scarcely affected the activity of both MAO enzymes as well as extracellular levels of 5-HT and DA. In this comparative study, MDMA, PMA, and 4-MTA functioned similar to PMMA, a typical empathogen; these findings therefore could be helpful in clarifying the psychopharmacological properties of amphetamine-related, empathogenic designer drugs.

  16. Fasudil hydrochloride hydrate, a Rho-kinase inhibitor, suppresses 5-hydroxytryptamine-induced pulmonary artery smooth muscle cell proliferation via JNK and ERK1/2 pathway.

    PubMed

    Chen, Xue-Yan; Dun, Jie-Ning; Miao, Qing-Feng; Zhang, Yong-Jian

    2009-01-01

    Excessive proliferation of pulmonary artery smooth muscle cells (PASMCs) plays a critical role in the development of pulmonary artery hypertension, and inhibition of PASMC proliferation has been shown to be beneficial to patients with this disease. Recent studies indicate that Rho/ROCK is critically involved in the proliferation of smooth muscle cells. However, the signal transduction of Rho/ROCK and its downstream signaling are not fully understood. In the present study, we investigated the antiproliferation effect of fasudil hydrochloride hydrate, a Rho-kinase inhibitor, on rat PASMC proliferation, and the possible relation of Rho/ROCK to ERK, JNK pathways. The results indicate that fasudil effectively inhibited 5-HT-induced PASMC proliferation, as evaluated by MTT assay and protein expression of proliferating cell nuclear antigen. Flow cytometry analysis showed that fasudil markedly blocked 5-HT-induced cell-cycle progression by arresting the cells in the G(0)/G(1) phase. Consistently, 5-HT-induced ROCK-1 mRNA expression and MYPT-1 phosphorylation were markedly suppressed by fasudil. In addition, fasudil significantly decreased 5-HT-induced JNK activation, ERK translocation to the nucleus and subsequent c-fos and c-jun expression. Taken together, these results indicate that Rho/ROCK is essential for PASMC proliferation produced by 5-HT. Fasudil effectively suppressed 5-HT-induced PASMC proliferation and cell-cycle progression, which was associated with inhibition of JNK activation, ERK translocation to nucleus and subsequent c-fos and c-jun expression.

  17. Sphagnum mosses--masters of efficient N-uptake while avoiding intoxication.

    PubMed

    Fritz, Christian; Lamers, Leon P M; Riaz, Muhammad; van den Berg, Leon J L; Elzenga, Theo J T M

    2014-01-01

    Peat forming Sphagnum mosses are able to prevent the dominance of vascular plants under ombrotrophic conditions by efficiently scavenging atmospherically deposited nitrogen (N). N-uptake kinetics of these mosses are therefore expected to play a key role in differential N availability, plant competition, and carbon sequestration in Sphagnum peatlands. The interacting effects of rain N concentration and exposure time on moss N-uptake rates are, however, poorly understood. We investigated the effects of N-concentration (1, 5, 10, 50, 100, 500 µM), N-form ((15)N-ammonium or nitrate) and exposure time (0.5, 2, 72 h) on uptake kinetics for Sphagnum magellanicum from a pristine bog in Patagonia (Argentina) and from a Dutch bog exposed to decades of N-pollution. Uptake rates for ammonium were higher than for nitrate, and N-binding at adsorption sites was negligible. During the first 0.5 h, N-uptake followed saturation kinetics revealing a high affinity (Km 3.5-6.5 µM). Ammonium was taken up 8 times faster than nitrate, whereas over 72 hours this was only 2 times. Uptake rates decreased drastically with increasing exposure times, which implies that many short-term N-uptake experiments in literature may well have overestimated long-term uptake rates and ecosystem retention. Sphagnum from the polluted site (i.e. long-term N exposure) showed lower uptake rates than mosses from the pristine site, indicating an adaptive response. Sphagnum therefore appears to be highly efficient in using short N pulses (e.g. rainfall in pristine areas). This strategy has important ecological and evolutionary implications: at high N input rates, the risk of N-toxicity seems to be reduced by lower uptake rates of Sphagnum, at the expense of its long-term filter capacity and related competitive advantage over vascular plants. As shown by our conceptual model, interacting effects of N-deposition and climate change (changes in rainfall) will seriously alter the functioning of Sphagnum peatlands.

  18. Uptake of trimethoprim by renal cortex.

    PubMed

    Cacini, W; Myre, S A

    1985-10-01

    The purpose of this study was to examine the mechanisms involved in the uptake of the urinary antibacterial drug trimethoprim by incubated slices of rat renal cortex. Concentration-dependent studies of the uptake process demonstrated that a saturable component was involved. The results of inhibitor studies as well as the time-course pattern support the conclusion that at least two processes are involved in the uptake of trimethoprim. These include active transport via the organic cation system, accounting for about 40% of the total uptake, and a second component that continues to operate under conditions of inhibited cellular metabolism. Chromatographic examination of post-incubation bathing medium and slice extracts failed to demonstrate renal cortex metabolism of trimethoprim. PMID:4052093

  19. Nitrogen uptake and utilization by intact plants

    NASA Technical Reports Server (NTRS)

    Raper, C. D., Jr.; Tolley-Henry, L. C.

    1986-01-01

    The results of experiments support the proposed conceptual model that relates nitrogen uptake activity by plants as a balanced interdependence between the carbon-supplying function of the shoot and the nitrogen-supplying function of the roots. The data are being used to modify a dynamic simulation of plant growth, which presently describes carbon flows through the plant, to describe nitrogen uptake and assimilation within the plant system. Although several models have been proposed to predict nitrogen uptake and partitioning, they emphasize root characteristics affecting nutrient uptake and relay on empirical methods to describe the relationship between nitrogen and carbon flows within the plant. Researchers, on the other hand, propose to continue to attempt a mechanistic solution in which the effects of environment on nitrogen (as well as carbon) assimilation are incorporated through their direct effects on photosynthesis, respiration, and aging processes.

  20. CONVERGING PATTERNS OF UPTAKE AND HYDRAULIC REDISTRIBUTION OF SOIL WATER IN CONTRASTING WOODY VEGETATION TYPES

    EPA Science Inventory

    We used concurrent measurements of soil water content and soil water potential (Ysoil) to assess the effects of Ysoil on uptake and hydraulic redistribution (HR) of soil water by roots during seasonal drought cycles in six sites characterized by different types and amounts of woo...

  1. Gallium-67 uptake in meningeal sarcoidosis

    SciTech Connect

    Ayres, J.G.; Hicks, B.H.; Maisey, M.N.

    1986-07-01

    A case of sarcoidosis limited to the central nervous system is described in which the diagnosis was suggested by high Ga-67 uptake in the cranial and spinal meninges. The diagnosis was confirmed by meningeal biopsy. Treatment with oral corticosteroids resulted in clinical improvement and marked reduction in Ga-67 uptake in the meninges. This is the first reported case of the central nervous system sarcoid diagnosed by Ga-67 imaging.

  2. Diaphragm and Laryngeal FDG Uptake With Hiccups.

    PubMed

    Srivastava, Madhur K; Jain, Avani S; Panneer, Venkat; Muthukrishnan, Indirani; Simon, Shelley

    2015-11-01

    F-FDG PET/CT study is a well-established investigation in diagnosis, treatment evaluation, and follow-up of malignant tumors. It is very important to know the normal biodistribution and physiologic uptake of F-FDG to prevent it from confusing as malignant disease. This article describes unusual but physiological uptake in the laryngeal and diaphragmatic muscles in a patient presenting as metastatic adenocarcinoma with unknown primary having hiccups. PMID:26204217

  3. General aspects of muscle glucose uptake.

    PubMed

    Alvim, Rafael O; Cheuhen, Marcel R; Machado, Silmara R; Sousa, André Gustavo P; Santos, Paulo C J L

    2015-03-01

    Glucose uptake in peripheral tissues is dependent on the translocation of GLUT4 glucose transporters to the plasma membrane. Studies have shown the existence of two major signaling pathways that lead to the translocation of GLUT4. The first, and widely investigated, is the insulin activated signaling pathway through insulin receptor substrate-1 and phosphatidylinositol 3-kinase. The second is the insulin-independent signaling pathway, which is activated by contractions. Individuals with type 2 diabetes mellitus have reduced insulin-stimulated glucose uptake in skeletal muscle due to the phenomenon of insulin resistance. However, those individuals have normal glucose uptake during exercise. In this context, physical exercise is one of the most important interventions that stimulates glucose uptake by insulin-independent pathways, and the main molecules involved are adenosine monophosphate-activated protein kinase, nitric oxide, bradykinin, AKT, reactive oxygen species and calcium. In this review, our main aims were to highlight the different glucose uptake pathways and to report the effects of physical exercise, diet and drugs on their functioning. Lastly, with the better understanding of these pathways, it would be possible to assess, exactly and molecularly, the importance of physical exercise and diet on glucose homeostasis. Furthermore, it would be possible to assess the action of drugs that might optimize glucose uptake and consequently be an important step in controlling the blood glucose levels in diabetic patients, in addition to being important to clarify some pathways that justify the development of drugs capable of mimicking the contraction pathway.

  4. Substrate stiffness regulates cellular uptake of nanoparticles.

    PubMed

    Huang, Changjin; Butler, Peter J; Tong, Sheng; Muddana, Hari S; Bao, Gang; Zhang, Sulin

    2013-04-10

    Nanoparticle (NP)-bioconjugates hold great promise for more sensitive disease diagnosis and more effective anticancer drug delivery compared with existing approaches. A critical aspect in both applications is cellular internalization of NPs, which is influenced by NP properties and cell surface mechanics. Despite considerable progress in optimization of the NP-bioconjugates for improved targeting, the role of substrate stiffness on cellular uptake has not been investigated. Using polyacrylamide (PA) hydrogels as model substrates with tunable stiffness, we quantified the relationship between substrate stiffness and cellular uptake of fluorescent NPs by bovine aortic endothelial cells (BAECs). We found that a stiffer substrate results in a higher total cellular uptake on a per cell basis, but a lower uptake per unit membrane area. To obtain a mechanistic understanding of the cellular uptake behavior, we developed a thermodynamic model that predicts that membrane spreading area and cell membrane tension are two key factors controlling cellular uptake of NPs, both of which are modulated by substrate stiffness. Our experimental and modeling results not only open up new avenues for engineering NP-based cancer cell targets for more effective in vivo delivery but also contribute an example of how the physical environment dictates cellular behavior and function.

  5. Neptunium uptake by serum transferrin.

    PubMed

    Llorens, Isabelle; Den Auwer, Christophe; Moisy, Philippe; Ansoborlo, Eric; Vidaud, Claude; Funke, Harld

    2005-04-01

    Although of major impact in terms of biological and environmental hazards, interactions of actinide cations with biological molecules are only partially understood. Human serum transferrin (Tf) is one of the major iron carriers in charge of iron regulation in the cell cycle and consequently contamination by actinide cations is a critical issue of nuclear toxicology. Combined X-ray absorption spectroscopy (XAS) and near infrared absorption spectrometry were used to characterize a new complex between Tf and Np (IV) with the synergistic nitrilotriacetic acid (NTA) anion. Description of the neptunium polyhedron within the iron coordination site is given.

  6. Endocytosis of the major yolk proteins of the silkmoth, Hyalophora cecropia: Uptake kinetics and interactions

    SciTech Connect

    Kulakosky, P.C.

    1989-01-01

    The oocytes of Lepidopteran insects take up several yolk proteins in defined proportions even though their relative availability in the hemolymph changes during the several days required to complete yolk formation in all the eggs. There are three hemolymph yolk precursors, vitellogenin, microvitellogenin and lipophorin; one precursor, paravitellogenin is produced in the ovary. The control mechanism for their proportional endocytosis is not known. In this thesis, the author describe the purification of all four proteins and the radiolabeling of the hemolymph precursors. The radiolabeled proteins were tested with an in vitro incubation system to assess the biological activity of the proteins and the reliability of the incubation methods. All of the labeled probes were transferred from the incubation medium to yolk spheres within the oocyte in a saturable, energy-dependent, and stage-specific manner. The rates of uptake were similar to the estimated rates of uptake in situ. The concentration dependence of in vitro uptake was investigated and found to be consistent with in situ concentrations and the composition of yolk in mature eggs. Two precursors, vitellogenin and lipophorin, competed for uptake indicating that they share a common binding site while the third, microvitellin, did not compete with the others. Though vitellogenin and lipophorin competed for uptake, only vitellogenin displayed the unique ability to increase the uptake rate of microvitellin and fluid in vitro.

  7. Nitrogen deposition and prey nitrogen uptake control the nutrition of the carnivorous plant Drosera rotundifolia.

    PubMed

    Millett, J; Foot, G W; Svensson, B M

    2015-04-15

    Nitrogen (N) deposition has important negative impacts on natural and semi-natural ecosystems, impacting on biotic interactions across trophic levels. Low-nutrient systems are particularly sensitive to changes in N inputs and are therefore more vulnerable to N deposition. Carnivorous plants are often part of these ecosystems partly because of the additional nutrients obtained from prey. We studied the impact of N deposition on the nutrition of the carnivorous plant Drosera rotundifolia growing on 16 ombrotrophic bogs across Europe. We measured tissue N, phosphorus (P) and potassium (K) concentrations and prey and root N uptake using a natural abundance stable isotope approach. Our aim was to test the impact of N deposition on D. rotundifolia prey and root N uptake, and nutrient stoichiometry. D. rotundifolia root N uptake was strongly affected by N deposition, possibly resulting in reduced N limitation. The contribution of prey N to the N contained in D. rotundifolia ranged from 20 to 60%. N deposition reduced the maximum amount of N derived from prey, but this varied below this maximum. D. rotundifolia tissue N concentrations were a product of both root N availability and prey N uptake. Increased prey N uptake was correlated with increased tissue P concentrations indicating uptake of P from prey. N deposition therefore reduced the strength of a carnivorous plant-prey interaction, resulting in a reduction in nutrient transfer between trophic levels. We suggest that N deposition has a negative impact on D. rotundifolia and that responses to N deposition might be strongly site specific.

  8. Caged mussels and semipermeable membrane devices as indicators of organic contaminant uptake in Dorchester and Duxbury Bays, Massachusetts

    SciTech Connect

    Peven, C.S.; Uhler, A.D.; Querzoli, F.J.

    1996-02-01

    An experiment to measure organic contaminant depuration by the blue mussel (Mytilus edulis) was carried out by transplanting mussels in stainless steel cages from a known contaminated site in Dorchester Bay, Massachusetts to a documented clean site in Duxbury Bay, Massachusetts approximately 30 nmi south of the original collection site. A parallel contaminant uptake experiment was performed in which mussels from Duxbury Bay were collected and deployed in similar cages in Dorchester Bay. The bivalves were collected from each transplant site at set intervals over a period of 95 days to monitor the rates and selectivity of depuration and uptake, respectively, of polynuclear atomic hydrocarbons (PAH), polychlorinated biphenyls (PCB), and chlorinated pesticides. In a related study, semipermeable membrane devices (SPMD: polyethylene bags) containing the lipid material triolein were deployed in Dorchester Bay and collected at the same frequency as the caged mussels to evaluate their effectiveness as models for estimating bioconcentration of target organic contaminants. At the Duxbury site, results suggest that the caged mussels depurated contaminants within 68 days to levels found in native animals at the site. At the Dorchester site, bivalves concentrated the contaminants to a level similar to the native M. edulis. PCB and DDT uptake rates were found to be similar between caged mussels and SPMDs; PAH uptake by the SPMDs was initially lower than by transplanted bivalves. PCB and PAH assemblages were noticeably different between bivalves and SPMDs deployed at the same site.

  9. In vivo radiometric analysis of glucose uptake and distribution in mouse bone

    PubMed Central

    Zoch, Meredith L; Abou, Diane S; Clemens, Thomas L; Thorek, Daniel L J; Riddle, Ryan C

    2016-01-01

    Bone formation and remodeling occurs throughout life and requires the sustained activity of osteoblasts and osteoclasts, particularly during periods of rapid bone growth. Despite increasing evidence linking bone cell activity to global energy homeostasis, little is known about the relative energy requirements or substrate utilization of bone cells. In these studies, we measured the uptake and distribution of glucose in the skeleton in vivo using positron-emitting 18F-fluorodeoxyglucose ([18F]-FDG) and non-invasive, high-resolution positron emission tomography/computed tomography (PET/CT) imaging and ex vivo autoradiography. Assessment of [18F]-FDG uptake demonstrated that relative to other tissues bone accumulated a significant fraction of the total dose of the glucose analog. Skeletal accumulation was greatest in young mice undergoing the rapid bone formation that characterizes early development. PET/CT imaging revealed that [18F]-FDG uptake was greatest in the epiphyseal and metaphyseal regions of long bones, which accords with the increased osteoblast numbers and activity at this skeletal site. Insulin administration significantly increased skeletal accumulation of [18F]-FDG, while uptake was reduced in mice lacking the insulin receptor specifically in osteoblasts or fed a high-fat diet. Our results indicated that the skeleton is a site of significant glucose uptake and that its consumption by bone cells is subject to regulation by insulin and disturbances in whole-body metabolism. PMID:27088042

  10. In vivo radiometric analysis of glucose uptake and distribution in mouse bone.

    PubMed

    Zoch, Meredith L; Abou, Diane S; Clemens, Thomas L; Thorek, Daniel L J; Riddle, Ryan C

    2016-01-01

    Bone formation and remodeling occurs throughout life and requires the sustained activity of osteoblasts and osteoclasts, particularly during periods of rapid bone growth. Despite increasing evidence linking bone cell activity to global energy homeostasis, little is known about the relative energy requirements or substrate utilization of bone cells. In these studies, we measured the uptake and distribution of glucose in the skeleton in vivo using positron-emitting (18)F-fluorodeoxyglucose ([(18)F]-FDG) and non-invasive, high-resolution positron emission tomography/computed tomography (PET/CT) imaging and ex vivo autoradiography. Assessment of [(18)F]-FDG uptake demonstrated that relative to other tissues bone accumulated a significant fraction of the total dose of the glucose analog. Skeletal accumulation was greatest in young mice undergoing the rapid bone formation that characterizes early development. PET/CT imaging revealed that [(18)F]-FDG uptake was greatest in the epiphyseal and metaphyseal regions of long bones, which accords with the increased osteoblast numbers and activity at this skeletal site. Insulin administration significantly increased skeletal accumulation of [(18)F]-FDG, while uptake was reduced in mice lacking the insulin receptor specifically in osteoblasts or fed a high-fat diet. Our results indicated that the skeleton is a site of significant glucose uptake and that its consumption by bone cells is subject to regulation by insulin and disturbances in whole-body metabolism. PMID:27088042

  11. Utilization of a Model for Uptake of Cadmium by Plants as a Phytoremediation Assessment Tool

    NASA Astrophysics Data System (ADS)

    Takahashi, M.; Furbish, D. J.; Clarke, J.

    2008-12-01

    Some traditional methods of environmental remediation, such as removal and disposal of contaminated soil, are loosing economic favor and public acceptance, while others, such as in situ phytoremediation, are being carefully examined because of their attractiveness as environmentally friendly, low-cost solutions to site clean-up. The success of phytoremediation strategies, however, hinges on the ability of selected plants, or plant communities, to effectively uptake, accumulate and tolerate targeted contaminants. Heavy metals, specifically cadmium (Cd), are not essential nutrients to plants. However, chemically similar zinc (Zn) is a micronutrient and is actively taken up by hyperaccumulators. For this reason, the mechanisms involved in uptake of Cd parallel those of Zn. Ideally, Cd would be allocated to the stem, leaf, and/or flower, where it becomes harvestable. Our modeling work simulates the uptake and the storage of Cd in a growing hyperaccumulator. After uptake, Cd is partitioned between adsorption to plant tissue and upward movement to leaves driven by transpiration. Uptake, adsorption and transport are also regulated by phytotoxicity. Simulations suggest that a young plant with small biomass can quickly reach phytotoxicity, which shuts down the normal operation of the plant. Conversely, mature plants on a mildly contaminated site, if harvested before the plants die due to phytotoxicity or natural cause, not only survive but may occasionally thrive. The immediate aim is to estimate the effectiveness and limitations of Cd uptake by hyperaccumulators. The eventual goal of this study is to expand the model in spatial and temporal scales, from individual plants to the community scale, and from one harvest interval to several generations. Understanding the interface between physical and biological processes, specifically the uptake and release of contaminants, provides scientists and engineers tools to assess whether phytoremediation is a reasonable strategy for a

  12. Quantitating Antibody Uptake In Vivo: Conditional Dependence on Antigen Expression Levels

    PubMed Central

    Thurber, Greg M.; Weissleder, Ralph

    2010-01-01

    Purpose Antibodies form an important class of cancer therapeutics, and there is intense interest in using them for imaging applications in diagnosis and monitoring of cancer treatment. Despite the expanding body of knowledge describing pharmacokinetic and pharmacodynamic interactions of antibodies in vivo, discrepancies remain over the effect of antigen expression level on tumoral uptake with some reports indicating a relationship between uptake and expression and others showing no correlation. Procedures Using a cell line with high EpCAM expression and moderate EGFR expression, fluorescent antibodies with similar plasma clearance were imaged in vivo. A mathematical model and mouse xenograft experiments were used to describe the effect of antigen expression on uptake of these high affinity antibodies. Results As predicted by the theoretical model, under subsaturating conditions, uptake of the antibodies in such tumors is similar because localization of both probes is limited by delivery from the vasculature. In a separate experiment, when the tumor is saturated, the uptake becomes dependent on the number of available binding sites. In addition, targeting of small micrometastases is shown to be higher than larger vascularized tumors. Conclusions These results are consistent with the prediction that high affinity antibody uptake is dependent on antigen expression levels for saturating doses and delivery for subsaturating doses. It is imperative for any probe to understand whether quantitative uptake is a measure of biomarker expression or transport to the region of interest. The data provide support for a predictive theoretical model of antibody uptake, enabling it to be used as a starting point for the design of more efficacious therapies and timely quantitative imaging probes. PMID:20809210

  13. Expression of the hepatocellular chloride-dependent sulfobromophthalein uptake system in Xenopus laevis oocytes.

    PubMed Central

    Jacquemin, E; Hagenbuch, B; Stieger, B; Wolkoff, A W; Meier, P J

    1991-01-01

    The expression of the basolateral chloride-activated organic anion uptake system of rat hepatocytes has been studied in Xenopus laevis oocytes. Injection of oocytes with rat liver poly(A)+RNA resulted in the functional expression of chloride-dependent sulfobromophthalein (BSP) uptake within 3-5 d. This expressed chloride-dependent BSP uptake system exhibited saturation kinetics (apparent Km approximately 6.2 microM) and efficiently extracted BSP from its binding sites on BSA. Furthermore, the chloride-activated portion of BSP uptake was inhibited by bilirubin (10 microM; inhibition 53%), 4,4'-diisothiocyano-2,2-disulfonic acid stilbene (DIDS, 100 microM; 80%), taurocholate (100 microM; 80%), and cholate (200 microM; 95%). In contrast to results with total rat liver mRNA, injection of mRNA derived from the Na+/bile acid cotransporter cDNA (Hagenbuch, B., B. Stieger, M. Foguet, H. Lübbert, and P. J. Meier. 1991. Proc. Natl. Acad. Sci. USA. In press.) had no effect on BSP uptake into oocytes. Size fractionation of total rat liver mRNA revealed that a 2.0- to 3.5-kb size-class mRNA was sufficient to express the hepatic chloride-dependent BSP uptake system. These data indicate that "expression cloning" in oocytes represents a promising approach to ultimately clone the cDNA coding for the hepatocyte high affinity, chloride-dependent organic anion uptake system. Furthermore, the results confirm that the Na+/bile acid cotransport system does not mediate BSP uptake. PMID:1752967

  14. Significance of incidental focal uptake in prostate on 18-fluoro-2-deoxyglucose positron emission tomography CT images.

    PubMed

    Han, E J; H O, J; Choi, W H; Yoo, I R; Chung, S K

    2010-11-01

    To evaluate the clinical significance of incidental focal prostate fluorodeoxyglucose (FDG) uptake, we reviewed 18-F-FDG positron emission tomography (PET)/CT scans from 2003 to 2007 and selected cases with focal FDG uptake in prostate. Cases of known prostate cancer were excluded. The maximum standardised uptake value (SUV(max)), site (central or peripheral) and pattern (discrete or ill-defined) of FDG uptake, calcification (present or absent) and prostate volume (<30 or ≥30 cc) were recorded. The PET/CT findings were correlated with serum prostate-specific antigen (PSA) levels, imaging studies, clinical follow-up and biopsy. Of a total of 5119 cases, 63 (1.2%) demonstrated focal FDG uptake in prostate. Eight cases were lost to follow-up. Among the 55 cases with follow-up, malignancy was confirmed by biopsy in 3 (5.4%). The three malignant cases had SUV(max) values of 3.3, 3.6 and 2.3, and all were noted in the peripheral portion of prostate; two of these cases had a discrete FDG uptake pattern, none had calcification corresponding to the FDG uptake area and one had a prostatic volume greater than 30 cc. The mean SUV(max) of 52 benign cases was 3.2 ± 1.7 and focal FDG uptake was noted in the peripheral portion in 34 (65%), 20 (38%) cases showed a discrete FDG uptake pattern, 35 (67%) were accompanied by calcification and 32 (62%) had a prostatic volume greater than 30 cc. The majority of cases demonstrating focal FDG uptake in prostate were benign and no PET/CT finding could reliably differentiate benign from malignant lesions; however, when discrete focal FDG uptake without coincidental calcification is seen, particularly in the peripheral zone of the prostate, further clinical evaluation is recommended.

  15. Examination of the mechanism of action of nitrogen monoxide on iron uptake from transferrin.

    PubMed

    Watts, R N; Richardson, D R

    2000-08-01

    Nitrogen monoxide (NO) exerts many of its functions by binding to iron (Fe) in the active sites of a number of key proteins. Previously we have shown that NO produced by NO-generating agents decreased cellular Fe uptake from transferrin (Tf). However, the mechanism of this effect was not elucidated. In this study we examined the possible mechanisms whereby NO could interfere with Fe uptake. Our experiments demonstrate that NO produced by the NO generator S-nitroso-N-acetylpenicillamine was slightly more effective than the Fe chelator deferoxamine at reducing iron 59 uptake from 59Fe-labeled Tf by LMTK- fibroblasts. Other NO generators including S-nitrosoglutathione (GSNO) and spermine-NONOate also decreased 59Fe uptake from 59Fe-labeled Tf. In contrast, precursors of these compounds that do not release NO had no effect. When the RAW264.7 macrophage cell line was activated to produce NO by incubation with lipopolysaccharide or lipopolysaccharide and interferon-gamma, a decrease in 59Fe uptake from 59Fe-labeled Tf was also observed. Experiments with electron paramagnetic resonance spectroscopy and ultraviolet-Vis spectrophotometry demonstrated that NO did not prevent Fe uptake by binding to the Fe-ligating sites of Tf, suggesting that it acted more distally. Because the uptake of Fe is an energy-dependent process, and since NO inhibits mitochondrial respiration, cellular adenosine triphosphate (ATP) was estimated after incubation with GSNO. In the presence of D-glucose (D-G), GSNO reduced ATP levels by 35% as compared with the control, while in the absence of D-G, GSNO reduced ATP by 72%. When the same experiments were performed with D-fructose (D-F), which cannot be efficiently metabolized by fibroblasts, no "rescue" effect was observed on ATP levels. The addition of D-G to GSNO prevented the decrease in 59Fe uptake from 59Fe-labeled Tf while D-F did not, in good correlation with their effects on ATP levels. These results suggest that D-G acts as a salvage

  16. Selenium Uptake and Volatilization by Marine Algae

    NASA Astrophysics Data System (ADS)

    Luxem, Katja E.; Vriens, Bas; Wagner, Bettina; Behra, Renata; Winkel, Lenny H. E.

    2015-04-01

    Selenium (Se) is an essential trace nutrient for humans. An estimated one half to one billion people worldwide suffer from Se deficiency, which is due to low concentrations and bioavailability of Se in soils where crops are grown. It has been hypothesized that more than half of the atmospheric Se deposition to soils is derived from the marine system, where microorganisms methylate and volatilize Se. Based on model results from the late 1980s, the atmospheric flux of these biogenic volatile Se compounds is around 9 Gt/year, with two thirds coming from the marine biosphere. Algae, fungi, and bacteria are known to methylate Se. Although algal Se uptake, metabolism, and methylation influence the speciation and bioavailability of Se in the oceans, these processes have not been quantified under environmentally relevant conditions and are likely to differ among organisms. Therefore, we are investigating the uptake and methylation of the two main inorganic Se species (selenate and selenite) by three globally relevant microalgae: Phaeocystis globosa, the coccolithophorid Emiliania huxleyi, and the diatom Thalassiosira oceanica. Selenium uptake and methylation were quantified in a batch experiment, where parallel gas-tight microcosms in a climate chamber were coupled to a gas-trapping system. For E. huxleyi, selenite uptake was strongly dependent on aqueous phosphate concentrations, which agrees with prior evidence that selenite uptake by phosphate transporters is a significant Se source for marine algae. Selenate uptake was much lower than selenite uptake. The most important volatile Se compounds produced were dimethyl selenide, dimethyl diselenide, and dimethyl selenyl sulfide. Production rates of volatile Se species were larger with increasing intracellular Se concentration and in the decline phase of the alga. Similar experiments are being carried out with P. globosa and T. oceanica. Our results indicate that marine algae are important for the global cycling of Se

  17. Sugar uptake by the solventogenic clostridia.

    PubMed

    Mitchell, Wilfrid J

    2016-02-01

    The acetone-butanol-ethanol fermentation of solventogenic clostridia was operated as a successful, worldwide industrial process during the first half of the twentieth century, but went into decline for economic reasons. The recent resurgence in interest in the fermentation has been due principally to the recognised potential of butanol as a biofuel, and development of reliable molecular tools has encouraged realistic prospects of bacterial strains being engineered to optimise fermentation performance. In order to minimise costs, emphasis is being placed on waste feedstock streams containing a range of fermentable carbohydrates. It is therefore important to develop a detailed understanding of the mechanisms of carbohydrate uptake so that effective engineering strategies can be identified. This review surveys present knowledge of sugar uptake and its control in solventogenic clostridia. The major mechanism of sugar uptake is the PEP-dependent phosphotransferase system (PTS), which both transports and phosphorylates its sugar substrates and plays a central role in metabolic regulation. Clostridial genome sequences have indicated the presence of numerous phosphotransferase systems for uptake of hexose sugars, hexose derivatives and disaccharides. On the other hand, uptake of sugars such as pentoses occurs via non-PTS mechanisms. Progress in characterization of clostridial sugar transporters and manipulation of control mechanisms to optimise sugar fermentation is described.

  18. The Uptake of GABA in Trypanosoma cruzi.

    PubMed

    Galvez Rojas, Robert L; Ahn, Il-Young; Suárez Mantilla, Brian; Sant'Anna, Celso; Pral, Elizabeth Mieko Furusho; Silber, Ariel Mariano

    2015-01-01

    Gamma aminobutyric acid (GABA) is widely known as a neurotransmitter and signal transduction molecule found in vertebrates, plants, and some protozoan organisms. However, the presence of GABA and its role in trypanosomatids is unknown. Here, we report the presence of intracellular GABA and the biochemical characterization of its uptake in Trypanosoma cruzi, the etiological agent of Chagas' disease. Kinetic parameters indicated that GABA is taken up by a single transport system in pathogenic and nonpathogenic forms. Temperature dependence assays showed a profile similar to glutamate transport, but the effect of extracellular cations Na(+) , K(+) , and H(+) on GABA uptake differed, suggesting a different uptake mechanism. In contrast to reports for other amino acid transporters in T. cruzi, GABA uptake was Na(+) dependent and increased with pH, with a maximum activity at pH 8.5. The sensitivity to oligomycin showed that GABA uptake is dependent on ATP synthesis. These data point to a secondary active Na(+) /GABA symporter energized by Na(+) -exporting ATPase. Finally, we show that GABA occurs in the parasite's cytoplasm under normal culture conditions, indicating that it is regularly taken up from the culture medium or synthesized through an still undescribed metabolic pathway.

  19. Effect of insulin on muscle glutamate uptake

    PubMed Central

    Aoki, T. T.; Brennan, M. F.; Müller, W. A.; Moore, F. D.; Cahill, G. F.

    1972-01-01

    For decades, investigators concerned with protein metabolism in man have performed detailed amino acid analyses of human plasma obtained under a wide range of experimental situations. A large body of information has been used to calculated rates of protein synthesis and proteolysis. During the course of an investigation of the effect of intrabrachial artery infusion of insulin (70 μU/min per kg body weight) on glutamate uptake by human forearm muscle, it was discovered that plasma arterio-deep venous glutamate difference analysis failed to document any increase in the uptake of this amino acid, suggesting that insulin had little influence on glutamate uptake by muscle. However, whole blood glutamate analyses, performed on the same blood samples, revealed that (a) the resting muscle uptake of glutamate is smaller than previously reported and (b) insulin is capable of markedly increasing glutamate uptake by muscle from whole blood. Since the hematocrit was obtained on all samples, detailed analyses of the various compartments in which glutamate could be found were performed. It was determined that circulating blood cells have a dynamic role in glutamate transport. These data underscore the need for both whole blood and plasma amino acid analysis in investigations concerned with protein synthesis and/or amino acid flux, for analysis of plasma samples alone could be misleading as illustrated in the present study. Images PMID:5080414

  20. Vimentin mediates uptake of C3 exoenzyme.

    PubMed

    Rohrbeck, Astrid; Schröder, Anke; Hagemann, Sandra; Pich, Andreas; Höltje, Markus; Ahnert-Hilger, Gudrun; Just, Ingo

    2014-01-01

    Clostridium botulinum C3 exoenzyme (C3) selectively inactivates RhoA/B/C GTPases by ADP-ribosylation. Based on this substrate specificity C3 is a well-established tool in cell biology. C3 is taken up by eukaryotic cells although lacking an uptake and translocation domain. Based on different approaches vimentin was identified as membranous C3-interaction partner by mass spectrometry. Vimentin in fact was partly localized at the outer surface of hippocampal HT22 cells and J744A.1 macrophages. Domain analysis identified the rod domain as binding partner of C3. Vimentin was also involved in uptake of C3 as shown by knock down of vimentin in HT22 and J774A.1 cells. The involvement of vimentin in uptake of C3 was further supported by the findings that the vimentin disruptor acrylamide blocked uptake of C3. Vimentin is not only a major organizing element of the intermediate filament network but is also involved in both binding and uptake of C3 exoenzyme. PMID:24967582

  1. The Uptake of GABA in Trypanosoma cruzi.

    PubMed

    Galvez Rojas, Robert L; Ahn, Il-Young; Suárez Mantilla, Brian; Sant'Anna, Celso; Pral, Elizabeth Mieko Furusho; Silber, Ariel Mariano

    2015-01-01

    Gamma aminobutyric acid (GABA) is widely known as a neurotransmitter and signal transduction molecule found in vertebrates, plants, and some protozoan organisms. However, the presence of GABA and its role in trypanosomatids is unknown. Here, we report the presence of intracellular GABA and the biochemical characterization of its uptake in Trypanosoma cruzi, the etiological agent of Chagas' disease. Kinetic parameters indicated that GABA is taken up by a single transport system in pathogenic and nonpathogenic forms. Temperature dependence assays showed a profile similar to glutamate transport, but the effect of extracellular cations Na(+) , K(+) , and H(+) on GABA uptake differed, suggesting a different uptake mechanism. In contrast to reports for other amino acid transporters in T. cruzi, GABA uptake was Na(+) dependent and increased with pH, with a maximum activity at pH 8.5. The sensitivity to oligomycin showed that GABA uptake is dependent on ATP synthesis. These data point to a secondary active Na(+) /GABA symporter energized by Na(+) -exporting ATPase. Finally, we show that GABA occurs in the parasite's cytoplasm under normal culture conditions, indicating that it is regularly taken up from the culture medium or synthesized through an still undescribed metabolic pathway. PMID:25851259

  2. Action on low immunization uptake.

    PubMed

    Azubuike, M C; Ehiri, J E

    1998-01-01

    Despite a number of initiatives and campaigns over the years, immunization coverage in most parts of Nigeria remains low. That low coverage contributes to high morbidity and mortality levels among children. Poor transport, an ineffective cold chain, shortages of trained manpower, and inadequate community support and involvement are some of the factors which explain the underutilization of the immunization service. Aba is a city of approximately 500,000 people in eastern Nigeria in which the majority of inhabitants are traders. Aba's primary health care committee decided that immunization centers should be established in or near main trading areas to accommodate traders who did not want to leave their goods in order to take their children to primary care facilities for immunization. Traders' representatives helped to identify 8 suitable locations for vaccination sites in 3 shopping centers, the local authority provided financial and political support, and the state government gave technical and logistical assistance. The project began in September 1990 and was publicized through the traders' networks, which also helped to mobilize the relevant resources. Since many trading families were reached for the first time at the special centers, immunization coverage improved significantly for the 6 vaccine-preventable childhood diseases. Moreover, the project gave health workers the opportunity to deliver other services and counseling on matters of public health importance.

  3. Increasing uptake of live attenuated influenza vaccine among children in the United States, 2008-2014.

    PubMed

    Rodgers, Loren; Pabst, Laura J; Chaves, Sandra S

    2015-01-01

    The Advisory Committee on Immunization Practices (ACIP) recommends annual influenza vaccination for all persons in the United States aged ≥6 months. On June 25, 2014, ACIP preferentially recommended live attenuated influenza vaccine (LAIV) for healthy children aged 2-8 years. Little is known about national LAIV uptake. To determine uptake of LAIV relative to inactivated influenza vaccine, we analyzed vaccination records from six immunization information system sentinel sites (approximately 10% of US population). LAIV usage increased over time in all sites. Among children 2-8 years of age vaccinated for influenza, exclusive LAIV usage in the collective sentinel site area increased from 20.1% (2008-09 season) to 38.0% (2013-14). During 2013-14, at least half of vaccinated children received LAIV in Minnesota (50.0%) and North Dakota (55.5%). Increasing LAIV usage suggests formulation acceptability, and this preexisting trend offers a favorable context for implementation of ACIP's preferential recommendation.

  4. Uptake of genetic testing for cancer predisposition.

    PubMed Central

    Evans, D G; Maher, E R; Macleod, R; Davies, D R; Craufurd, D

    1997-01-01

    Although there has been much debate about the uptake and effects of predictive testing for common cancers, such as breast and colon cancer, little has been published on the more classical tumour predisposing conditions, such as von Hippel-Lindau disease and familial adenomatous polyposis. Since 1990 the genetics departments in Manchester and Cambridge have had a genetic register for cancer predisposing syndromes and presymptomatic testing for these conditions has been offered once this has become possible. To investigate the factors that might influence uptake of genetic testing in familial cancer syndromes we have reviewed our experience. Demand for predictive testing has generally been high, but men had a lower uptake (77%) than a comparable group of women (93%) (p < 0.01). PMID:9321761

  5. Plant Water Uptake in Drying Soils1

    PubMed Central

    Lobet, Guillaume; Couvreur, Valentin; Meunier, Félicien; Javaux, Mathieu; Draye, Xavier

    2014-01-01

    Over the last decade, investigations on root water uptake have evolved toward a deeper integration of the soil and roots compartment properties, with the goal of improving our understanding of water acquisition from drying soils. This evolution parallels the increasing attention of agronomists to suboptimal crop production environments. Recent results have led to the description of root system architectures that might contribute to deep-water extraction or to water-saving strategies. In addition, the manipulation of root hydraulic properties would provide further opportunities to improve water uptake. However, modeling studies highlight the role of soil hydraulics in the control of water uptake in drying soil and call for integrative soil-plant system approaches. PMID:24515834

  6. Isotopic signatures of production and uptake of H2 by soil

    NASA Astrophysics Data System (ADS)

    Chen, Q.; Popa, M. E.; Batenburg, A. M.; Röckmann, T.

    2015-09-01

    Molecular hydrogen (H2) is the second most abundant reduced trace gas (after methane) in the atmosphere, but its biogeochemical cycle is not well understood. Our study focuses on the soil production and uptake of H2 and the associated isotope effects. Air samples from a grass field and a forest site in the Netherlands were collected using soil chambers. The results show that uptake and emission of H2 occurred simultaneously at all sampling sites, with strongest emission at the grassland sites where clover (N2 fixing legume) was present. The H2 mole fraction and deuterium content were measured in the laboratory to determine the isotopic fractionation factor during H2 soil uptake (αsoil) and the isotopic signature of H2 that is simultaneously emitted from the soil (δDsoil). By considering all net-uptake experiments, an overall fractionation factor for deposition of αsoil = kHD/kHH = 0.945 ± 0.004 (95 % CI) was obtained. The difference in mean αsoil between the forest soil 0.937 ± 0.008 and the grassland 0.951 ± 0.025 is not statistically significant. For two experiments, the removal of soil cover increased the deposition velocity (vd) and αsoil simultaneously, but a general positive correlation between vd and αsoil was not found in this study. When the data are evaluated with a model of simultaneous production and uptake, the isotopic composition of H2 that is emitted at the grassland site is calculated as δDsoil = (-530 ± 40) ‰. This is less deuterium-depleted than what is expected from isotope equilibrium between H2O and H2.

  7. Isotopic signatures of production and uptake of H2 by soil

    NASA Astrophysics Data System (ADS)

    Chen, Q.; Popa, M. E.; Batenburg, A. M.; Röckmann, T.

    2015-11-01

    Molecular hydrogen (H2) is the second most abundant reduced trace gas (after methane) in the atmosphere, but its biogeochemical cycle is not well understood. Our study focuses on the soil production and uptake of H2 and the associated isotope effects. Air samples from a grass field and a forest site in the Netherlands were collected using soil chambers. The results show that uptake and emission of H2 occurred simultaneously at all sampling sites, with strongest emission at the grassland sites where clover (N2 fixing legume) was present. The H2 mole fraction and deuterium content were measured in the laboratory to determine the isotopic fractionation factor during H2 soil uptake (αsoil) and the isotopic signature of H2 that is simultaneously emitted from the soil (δDsoil). By considering all net-uptake experiments, an overall fractionation factor for deposition of αsoil = kHD / kHH = 0.945 ± 0.004 (95 % CI) was obtained. The difference in mean αsoil between the forest soil 0.937 ± 0.008 and the grassland 0.951 ± 0.026 is not statistically significant. For two experiments, the removal of soil cover increased the deposition velocity (vd) and αsoil simultaneously, but a general positive correlation between vd and αsoil was not found in this study. When the data are evaluated with a model of simultaneous production and uptake, the isotopic composition of H2 that is emitted at the grassland site is calculated as δDsoil = (-530 ± 40) ‰. This is less deuterium depleted than what is expected from isotope equilibrium between H2O and H2.

  8. Characterization of a Dipartite Iron Uptake System from Uropathogenic Escherichia coli Strain F11*

    PubMed Central

    Koch, Doreen; Chan, Anson C. K.; Murphy, Michael E. P.; Lilie, Hauke; Grass, Gregor; Nies, Dietrich H.

    2011-01-01

    In the uropathogenic Escherichia coli strain F11, in silico genome analysis revealed the dicistronic iron uptake operon fetMP, which is under iron-regulated control mediated by the Fur regulator. The expression of fetMP in a mutant strain lacking known iron uptake systems improved growth under iron depletion and increased cellular iron accumulation. FetM is a member of the iron/lead transporter superfamily and is essential for iron uptake by the Fet system. FetP is a periplasmic protein that enhanced iron uptake by FetM. Recombinant FetP bound Cu(II) and the iron analog Mn(II) at distinct sites. The crystal structure of the FetP dimer reveals a copper site in each FetP subunit that adopts two conformations: CuA with a tetrahedral geometry composed of His44, Met90, His97, and His127, and CuB, a second degenerate octahedral geometry with the addition of Glu46. The copper ions of each site occupy distinct positions and are separated by ∼1.3 Å. Nearby, a putative additional Cu(I) binding site is proposed as an electron source that may function with CuA/CuB displacement to reduce Fe(III) for transport by FetM. Together, these data indicate that FetMP is an additional iron uptake system composed of a putative iron permease and an iron-scavenging and potentially iron-reducing periplasmic protein. PMID:21596746

  9. Potassium Uptake Modulates Staphylococcus aureus Metabolism

    PubMed Central

    Gries, Casey M.; Sadykov, Marat R.; Bulock, Logan L.; Chaudhari, Sujata S.; Thomas, Vinai C.; Bose, Jeffrey L.

    2016-01-01

    ABSTRACT As a leading cause of community-associated and nosocomial infections, Staphylococcus aureus requires sophisticated mechanisms that function to maintain cellular homeostasis in response to its exposure to changing environmental conditions. The adaptation to stress and maintenance of homeostasis depend largely on membrane activity, including supporting electrochemical gradients and synthesis of ATP. This is largely achieved through potassium (K+) transport, which plays an essential role in maintaining chemiosmotic homeostasis, affects antimicrobial resistance, and contributes to fitness in vivo. Here, we report that S. aureus Ktr-mediated K+ uptake is necessary for maintaining cytoplasmic pH and the establishment of a proton motive force. Metabolite analyses revealed that K+ deficiency affects both metabolic and energy states of S. aureus by impairing oxidative phosphorylation and directing carbon flux toward substrate-level phosphorylation. Taken together, these results underline the importance of K+ uptake in maintaining essential components of S. aureus metabolism. IMPORTANCE Previous studies describing mechanisms for K+ uptake in S. aureus revealed that the Ktr-mediated K+ transport system was required for normal growth under alkaline conditions but not under neutral or acidic conditions. This work focuses on the effect of K+ uptake on S. aureus metabolism, including intracellular pH and carbon flux, and is the first to utilize a pH-dependent green fluorescent protein (GFP) to measure S. aureus cytoplasmic pH. These studies highlight the role of K+ uptake in supporting proton efflux under alkaline conditions and uncover a critical role for K+ uptake in establishing efficient carbon utilization. PMID:27340697

  10. Potassium Uptake Modulates Staphylococcus aureus Metabolism.

    PubMed

    Gries, Casey M; Sadykov, Marat R; Bulock, Logan L; Chaudhari, Sujata S; Thomas, Vinai C; Bose, Jeffrey L; Bayles, Kenneth W

    2016-01-01

    As a leading cause of community-associated and nosocomial infections, Staphylococcus aureus requires sophisticated mechanisms that function to maintain cellular homeostasis in response to its exposure to changing environmental conditions. The adaptation to stress and maintenance of homeostasis depend largely on membrane activity, including supporting electrochemical gradients and synthesis of ATP. This is largely achieved through potassium (K(+)) transport, which plays an essential role in maintaining chemiosmotic homeostasis, affects antimicrobial resistance, and contributes to fitness in vivo. Here, we report that S. aureus Ktr-mediated K(+) uptake is necessary for maintaining cytoplasmic pH and the establishment of a proton motive force. Metabolite analyses revealed that K(+) deficiency affects both metabolic and energy states of S. aureus by impairing oxidative phosphorylation and directing carbon flux toward substrate-level phosphorylation. Taken together, these results underline the importance of K(+) uptake in maintaining essential components of S. aureus metabolism. IMPORTANCE Previous studies describing mechanisms for K(+) uptake in S. aureus revealed that the Ktr-mediated K(+) transport system was required for normal growth under alkaline conditions but not under neutral or acidic conditions. This work focuses on the effect of K(+) uptake on S. aureus metabolism, including intracellular pH and carbon flux, and is the first to utilize a pH-dependent green fluorescent protein (GFP) to measure S. aureus cytoplasmic pH. These studies highlight the role of K(+) uptake in supporting proton efflux under alkaline conditions and uncover a critical role for K(+) uptake in establishing efficient carbon utilization. PMID:27340697

  11. Enantioselective cellular uptake of chiral semiconductor nanocrystals

    NASA Astrophysics Data System (ADS)

    Martynenko, I. V.; Kuznetsova, V. A.; Litvinov, I. K.; Orlova, A. O.; Maslov, V. G.; Fedorov, A. V.; Dubavik, A.; Purcell-Milton, F.; Gun'ko, Yu K.; Baranov, A. V.

    2016-02-01

    The influence of the chirality of semiconductor nanocrystals, CdSe/ZnS quantum dots (QDs) capped with L- and D-cysteine, on the efficiency of their uptake by living Ehrlich Ascite carcinoma cells is studied by spectral- and time-resolved fluorescence microspectroscopy. We report an evident enantioselective process where cellular uptake of the L-Cys QDs is almost twice as effective as that of the D-Cys QDs. This finding paves the way for the creation of novel approaches to control the biological properties and behavior of nanomaterials in living cells.

  12. Cadmium uptake and resistance among selected bacteria

    SciTech Connect

    Burke, B.E.

    1987-01-01

    The purpose of this research was to determine the relationship between Cd resistance and Cd uptake by lake sediment bacteria. For the Gram positive and gram negative sediment bacteria that were tested, the relationship between resistance and Cd uptake varied and was dependent on the isolate under consideration. Results of this study indicated that bacterial communities in lake sediments may influence the concentration and availability of Cd in sediments and the water column. In addition, results of this study did not support the theory that the genes encoding for Cd resistance are usually carried on antibiotic resistance plasmids.

  13. Tracking the diurnal signal of plant water uptake through the hydrologic system

    NASA Astrophysics Data System (ADS)

    Blume, Theresa; Hassler, Sibylle; Heidbüchel, Ingo; Weiler, Markus; Simard, Sonia; Güntner, Andreas; Heinrich, Ingo

    2015-04-01

    Plant water uptake during summer is characterized by strong diurnal fluctuations. As a result a diurnal sink term is imposed on catchment storage, affecting the unsaturated zone, sometimes the saturated zone and even streamflow. Detecting this signal and understanding its propagation through the hydrological system may help to better quantify eco-hydrological connectivity. The extent and strength of the propagation of this signal from plant to soil to ground- and stream water was investigated with a unique setup of 46 field sites in Luxemburg and 15 field sites in Germany. These sites cover a range of geologies, soils, topographies and types of vegetation. Vegetation types include grassland, pine forest (young and old) and different deciduous forest stands. Available data at all sites includes information at high temporal resolution from 3-5 soil moisture profiles, matrix potential, piezometers and sapflow sensors (as proxy for plant water uptake) as well as standard climate data. At sites with access to a stream, discharge or water level is also recorded. Signal strength (amplitude of diurnal fluctuations) can thus be traced through the system and gives an indication of the physical sphere of influence of plant water uptake i.e. the "eco-hydro-connectivity". Temporal dynamics of signal strength furthermore suggest a shifting spatial distribution of root water uptake with time. The analysis of time lags (or phase shifts) between daily fluctuations in temperature, radiation, sapflow, soil water, groundwater and streamflow gives further insights into the processes driving and propagating these signals and inter-site comparison allows for the investigation of local controls.

  14. Contributions of Atmospheric CO and Hydrogen Uptake to Microbial Dynamics on Recent Hawaiian Volcanic Deposits†

    PubMed Central

    King, Gary M.

    2003-01-01

    A series of sites were established on Hawaiian volcanic deposits ranging from about 18 to 300 years old. Three sites occurred in areas that supported tropical rain forests; the remaining sites were in areas that supported little or no plant growth. Sites >26 years old consumed atmospheric CO and hydrogen at rates ranging from about 0.2 to 5 mg of CO m−2 day−1 and 0.1 to 4 mg of H2 m−2 day−1, respectively. Respiration, measured as CO2 production, for a subset of the sites ranged from about 40 to >1,400 mg of CO2 m−2 day−1. CO and H2 accounted for about 13 to 25% of reducing equivalent flow for all but a forested site, where neither substrate appeared significant. Based on responses to chloroform fumigation, hydrogen utilization appeared largely due to microbial uptake. In contrast to results for CO and hydrogen, methane uptake occurred consistently only at the forest site. Increasing deposit age was generally accompanied by increasing concentrations of organic matter and microbial biomass, measured as phospholipid phosphate. Exoenzymatic activities (acid and alkaline phosphatases and α- and β-glucosidases) were positively correlated with deposit age in spite of considerable variability within sites. The diversity of substrates utilized in Biolog Ecoplate assays also increased with deposit age, possibly reflecting changes in microbial community complexity. PMID:12839783

  15. Contributions of atmospheric CO and hydrogen uptake to microbial dynamics on recent Hawaiian volcanic deposits.

    PubMed

    King, Gary M

    2003-07-01

    A series of sites were established on Hawaiian volcanic deposits ranging from about 18 to 300 years old. Three sites occurred in areas that supported tropical rain forests; the remaining sites were in areas that supported little or no plant growth. Sites >26 years old consumed atmospheric CO and hydrogen at rates ranging from about 0.2 to 5 mg of CO m(-2) day(-1) and 0.1 to 4 mg of H(2) m(-2) day(-1), respectively. Respiration, measured as CO(2) production, for a subset of the sites ranged from about 40 to >1,400 mg of CO(2) m(-2) day(-1). CO and H(2) accounted for about 13 to 25% of reducing equivalent flow for all but a forested site, where neither substrate appeared significant. Based on responses to chloroform fumigation, hydrogen utilization appeared largely due to microbial uptake. In contrast to results for CO and hydrogen, methane uptake occurred consistently only at the forest site. Increasing deposit age was generally accompanied by increasing concentrations of organic matter and microbial biomass, measured as phospholipid phosphate. Exoenzymatic activities (acid and alkaline phosphatases and alpha- and beta-glucosidases) were positively correlated with deposit age in spite of considerable variability within sites. The diversity of substrates utilized in Biolog Ecoplate assays also increased with deposit age, possibly reflecting changes in microbial community complexity.

  16. Extrapulmonary sites of radiogallium accumulation in sarcoidosis

    SciTech Connect

    Sulavik, S.B.; Palestro, C.J.; Spencer, R.P.; Swyer, A.J.; Goldsmith, S.J.; Tierstein, A.S. )

    1990-12-01

    In an effort to detect extrapulmonary sites of radiogallium accumulation in cases of sarcoidosis, 145 separate Ga-67 citrate studies of 114 patients with biopsy-proven sarcoidosis were examined. The most characteristic extrapulmonary radiogallium uptake pattern was the panda sign in 47 patients (41%). The most common site of prominent extrapulmonary radiogallium uptake was the lacrimal glands in 101 patients (88%). Second most common was activity in one or more superficial lymph node regions such as the cervical, axillary, femoral, or inguinal in 19 patients (17%). Other extrapulmonary sites included breast uptake in 6 out of 80 women (8%), prominent splenic and nasal uptake in 9 (8%) patients, periportal accumulation in 7 (6%), and cutaneous/subcutaneous activity in 4 (4%). Because many of these individuals were receiving corticosteroids, the natural (untreated) prevalence of extrapulmonary findings may be even higher. Although the sensitivity and specificity of extrapulmonary radiogallium accumulation has still to be determined, many of the sites may be accessible to biopsy both for diagnostic purposes and to follow the effects of medications. It is therefore suggested that whole-body imaging be performed when radiogallium is administered to patients with suspected or known sarcoidosis.

  17. Uptake, translocation, and accumulation of polycyclic aromatic hydrocarbons in vegetation

    SciTech Connect

    Walton, B.T. ); Hoylman, A.M. )

    1992-12-01

    A review of the scientific literature was conducted to determine the potential for plants to take up polycyclic aromatic hydrocarbons (PAHs) from soils and the possibility of PAH movement from soils into vegetation at waste disposal sites associated with manufactured gas plants (MGP). Studies published since 1983 are considered in conjunction with previous publications and literature reviews on PAH uptake by vegetation. These studies indicate that the extent to which sorption to roots occurs is likely to be influenced by species-specific properties of the plant, physicochemical properties of each PAH, soil properties, and biodegradation rates of the PAHs in soil. PAHs containing five or more rings may sorb to plant roots but are not expected to be translocated to foliage in other than trace quantities. Uptake of naphthalene, anthracene, and benzo[a]anthracene by roots has been reported in the literature. In addition, eight PAHs of three and four rings (acenapthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene, and chrysene) were isolated from leaves and roots of four plant species collected near a coal tar disposal trench in eastern Tennessee. A total concentration of 5519 ng/g was observed for the eight PAHs in roots of lamb's quarters. Coal tar, in soil, was implicated as the source of PAHs in the four plant species.

  18. Classification of Physiological 18F-fluorodeoxyglucose Uptake in the Large Intestine: a Preliminary Study.

    PubMed

    Yasuda, Seiei; Kobayashi, Katsuyuki; Ono, Masao; Miyatake, Yoshiko; Miyauchi, Mizuho; Kato, Tatsuya; Tanaka, Tatsuro; Ito, Masayoshi; Yamamoto, Nobuhiko

    2014-09-20

    Varying degrees of physiological uptake of 18F-fluorodeoxyglucose (FDG) are often noted in the large intestine and can be problematic when interpreting positron emission tomography (PET) images. In relation to colorectal tumor detection with FDG PET, we tentatively classified physiological FDG uptake in the large intestine according to its patterns and intensity. Subjects were 144 asymptomatic individuals (109 men, 35 women; mean age 57.5 ± 10.1 years) in our cancer screening program who underwent total colonoscopy within 24 days of FDG PET study and showed no evidence of colonic lesions on colonoscopy. Distinct FDG uptake on FDG PET images was classified into four types: focal, defined as distinctly nodular and visible on at least 4 axial; localized, 2 to 8 cm with SUVmean ≥ 4; diffuse, > 8 cm with SUVmean ≥ 4; and mixed, of more than one type. SUVmeans were examined by placing multiple circular regions of interest of 1 cm in diameter on the axial images. We found 21 distinct FDG uptakes matching our criteria in 20 of 144 subjects (13.9%): focal (n = 4), localized (n = 1), diffuse (n = 14), and mixed (n = 1; focal and diffuse). With regard to colorectal tumor detection, 6 subjects (4.2%) with focal or localized type of uptake were considered at risk of false-positive tumor identification, and 15 subjects (10.4%) with diffuse type of uptake were considered at risk of their tumors being missed at the site of FDG uptake. To confirm the feasibility of our criteria, this classification should be tested with a larger number of subjects.

  19. Characterization of taurine binding, uptake, and release in the rat hypothalamus

    SciTech Connect

    Hanretta, A.T.

    1985-01-01

    The neurotransmitter criteria of specific receptors, inactivation, and release were experimentally examined for taurine in the hypothalamus. Specific membrane binding and synaptosomal uptake of taurine both displayed high affinity and low affinity systems. The neurotransmitter criterion of release was studied in superfused synaptosomes. Exposure of synaptosomes which had been preloaded with a concentration of (/sup 3/H)taurine in the high affinity uptake range (1.5 ..mu..M) to either 56 mM K/sup +/ or 100 ..mu..M veratridine evoked a Ca/sup 2 +/-independent release. Exposure of synaptosomes which had been preloaded with a concentration of (/sup 3/H)taurine in the low affinity uptake range (2 mM) to 56 mM K/sup +/ induced a Ca/sup 2 +/-independent release, whereas 100 /sup +/M veratridine did not, either in the presence or absence of Ca/sup 2 +/. Based on these results, as well as other observations, a model is proposed in which the high affinity uptake system is located on neuronal membranes and the low affinity uptake system is located on glial membranes. The mechanisms of binding, uptake, and release in relation to the cellular location of each are discussed. We conclude that the neurotransmitter criterion of activation by re-uptake is satisfied for taurine in the hypothalamus. However, the failure to demonstrate both a specific taurine receptor site and a Ca/sup 2 +/-dependent evoked release, necessitates that we conclude that taurine appears not to function as a hypothalamic neurotransmitter, at least not in the classical sense.

  20. Inhibition of Phosphate Uptake in Corn Roots by Aluminum-Fluoride Complexes1

    PubMed Central

    Façanha, Arnoldo Rocha; Okorokova-Façanha, Anna L.

    2002-01-01

    F forms stable complexes with Al at conditions found in the soil. Fluoroaluminate complexes (AlFx) have been widely described as effective analogs of inorganic phosphate (Pi) in Pi-binding sites of several proteins. In this work, we explored the possibility that the phytotoxicity of AlFx reflects their activity as Pi analogs. For this purpose, 32P-labeled phosphate uptake by excised roots and plasma membrane H+-ATPase activity were investigated in an Al-tolerant variety of maize (Zea mays L. var. dwarf hybrid), either treated or not with AlFx. In vitro, AlFx competitively inhibited the rate of root phosphate uptake as well as the H+-ATPase activity. Conversely, pretreatment of seedlings with AlFx in vivo promoted no effect on the H+-ATPase activity, whereas a biphasic effect on Pi uptake by roots was observed. Although the initial rate of phosphate uptake by roots was inhibited by AlFx pretreatment, this situation changed over the following minutes as the rate of uptake increased and a pronounced stimulation in subsequent 32Pi uptake was observed. This kinetic behavior suggests a reversible and competitive inhibition of the phosphate transporter by fluoroaluminates. The stimulation of root 32Pi uptake induced by AlFx pretreatment was tentatively interpreted as a phosphate starvation response. This report places AlF3 and AlF4− among Al-phytotoxic species and suggests a mechanism of action where the accumulation of Pi-mimicking fluoroaluminates in the soil may affect the phosphate absorption by plants. The biochemical, physiological, and environmental significance of these findings is discussed. PMID:12177489

  1. Agonist interactions with 5-HT3 receptor recognition sites in the rat entorhinal cortex labelled by structurally diverse radioligands.

    PubMed Central

    Barnes, J. M.; Barnes, N. M.; Costall, B.; Jagger, S. M.; Naylor, R. J.; Robertson, D. W.; Roe, S. Y.

    1992-01-01

    1. The pharmacological properties of 5-HT3 receptor recognition sites labelled with [3H]-(S)-zacopride, [3H]-LY278,584, [3H]-granisetron and [3H]-GR67330 in membranes prepared from the rat entorhinal cortex were investigated to assess the presence of cooperativity within the 5-HT3 receptor complex. 2. In rat entorhinal cortex homogenates, [3H]-(S)-zacopride, [3H]-LY278,584, [3H]-granisetron and [3H]-GR67330 labelled homogeneous densities of recognition sites (defined by granisetron, 10 microM) with high affinity (Bmax = 75 +/- 5, 53 +/- 5, 92 +/- 6 and 79 +/- 6 fmol mg-1 protein, respectively; pKd = 9.41 +/- 0.04, 8.69 +/- 0.14, 8.81 +/- 0.06 and 10.14 +/- 0.04 for [3H]-(S)-zacopride, [3H]-LY278,584, [3H]-granisetron and [3H]-GR67330, respectively, n = 3-8). 3. Quipazine and granisetron competed for the binding of each of the radioligands in the rat entorhinal cortex preparation at low nanomolar concentrations (pIC50; quipazine 9.38-8.51, granisetron 8.62-8.03), whilst the agonists, 5-hydroxytryptamine (5-HT), phenylbiguanide (PBG) and 2-methyl-5-HT competed at sub-micromolar concentrations (pIC50; 5-HT 7.16-6.42, PBG 7.52-6.40, 2-methyl-5-HT 7.38-6.09). 4. Competition curves generated with increasing concentrations of quipazine, PBG, 5-HT and 2-methyl-5-HT displayed Hill coefficients greater than unity when the 5-HT3 receptor recognition sites in the entorhinal cortex preparation were labelled with [3H]-LY278,584, [3H]-granisetron and [3H]-GR67330. These competing compounds displayed Hill coefficients of around unity when the sites were labelled with [3H]-(S)-zacopride. Competition for the binding of [3H]-(S)-zacopride, [3H]-LY278,584, [3H]-granisetron and [3H]-GR67330 by granisetron generated Hill coefficients around unity.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1559139

  2. The gut wall provides an effective barrier against nanoparticle uptake

    PubMed Central

    Sinnecker, Heike; Krause, Thorsten; Koelling, Sabine; Lautenschläger, Ingmar

    2014-01-01

    Summary Background: The omnipresence of nanoparticles (NPs) in numerous goods has led to a constant risk of exposure and inadvertent uptake for humans. This situation calls for thorough investigation of the consequences of NP intake. As the vast mucosa of the human gastrointestinal tract represents an attractive site of entry, we wanted to take a look on the fate that ingested NPs suffer in the gut. As a model to investigate NP uptake we used the isolated perfused rat small intestine. Differently sized fluorescent latex particles were used as exemplary anthropogenic NPs. Results: The particles were administered as bolus into the isolated intestine, and samples from the luminal, vascular and lymphatic compartments were collected over time. NP amounts in the different fluids were determined by fluorescence measurements. No particles could be detected in the vascular and lymphatic system. By contrast a major amount of NPs was found in luminal samples. Yet, a substantial share of particles could not be recovered in the fluid fractions, indicating a sink function of the intestinal tissue for NPs. A histological examination of the gut revealed that virtually no particles adhered to the epithelium or resided in the tissue, the bulk of particles seemed to be trapped in the mucus lining the gut tube. When this mucus was dissolved and removed from the gut almost the entire amount of particles missing could be recovered: over 95% of the given NPs were present in the two fractions, the luminal samples and the dissolved mucus. To foster NP uptake via an extended interaction time with the epithelium, the intestinal peristalsis was decelerated and the duration of the experiment was prolonged. Even under those conditions, no particle fluorescence was detected in the vascular and lymphatic samples. Conclusion: We could show that after intestinal exposure with a large dose of NPs the vast majority of NPs did obviously not come into contact with the epithelium but was either directly

  3. The Relationship Between Uptake and Questioning.

    ERIC Educational Resources Information Center

    Kebede, S.

    1999-01-01

    Considers whether it is possible to account for the phenomenon of uptake by looking at some of the discoursal features of the interactive work that goes on between an instructor and his students in biology lessons in the context of nonnative English-speaking instructors working with nonnative English-speaking students in a tertiary-level…

  4. Routes and mechanisms of extracellular vesicle uptake

    PubMed Central

    Mulcahy, Laura Ann; Pink, Ryan Charles; Carter, David Raul Francisco

    2014-01-01

    Extracellular vesicles (EVs) are small vesicles released by donor cells that can be taken up by recipient cells. Despite their discovery decades ago, it has only recently become apparent that EVs play an important role in cell-to-cell communication. EVs can carry a range of nucleic acids and proteins which can have a significant impact on the phenotype of the recipient. For this phenotypic effect to occur, EVs need to fuse with target cell membranes, either directly with the plasma membrane or with the endosomal membrane after endocytic uptake. EVs are of therapeutic interest because they are deregulated in diseases such as cancer and they could be harnessed to deliver drugs to target cells. It is therefore important to understand the molecular mechanisms by which EVs are taken up into cells. This comprehensive review summarizes current knowledge of EV uptake mechanisms. Cells appear to take up EVs by a variety of endocytic pathways, including clathrin-dependent endocytosis, and clathrin-independent pathways such as caveolin-mediated uptake, macropinocytosis, phagocytosis, and lipid raft–mediated internalization. Indeed, it seems likely that a heterogeneous population of EVs may gain entry into a cell via more than one route. The uptake mechanism used by a given EV may depend on proteins and glycoproteins found on the surface of both the vesicle and the target cell. Further research is needed to understand the precise rules that underpin EV entry into cells. PMID:25143819

  5. Thiamin function, metabolism, uptake, and transport.

    PubMed

    Manzetti, Sergio; Zhang, Jin; van der Spoel, David

    2014-02-11

    Vitamins are crucial components in the diet of animals and many other living organisms. One of these essential nutrients, thiamin, is known to be involved in several cell functions, including energy metabolism and the degradation of sugars and carbon skeletons. Other roles that are connected to this vitamin are neuronal communication, immune system activation, signaling and maintenance processes in cells and tissues, and cell-membrane dynamics. Because of the key functions of thiamin, uptake and transport through the body are crucial. Its uptake route is relatively complex, encompassing a variety of protein families, including the solute carrier anion transporters, the alkaline phosphatase transport system, and the human extraneuronal monoamine transporter family, some of which are multispecific proteins. There are two known structures of protein (subunits) involved in thiamin uptake in prokaryotes. Binding of thiamin to these proteins is strongly guided by electrostatic interactions. The lack of structural information about thiamin binding proteins for higher organisms remains a bottleneck for understanding the uptake process of thiamin in atomic detail. This review includes recent data on thiamin metabolism, related deficiencies and pathologies, and the latest findings on thiamin binding transporters.

  6. Direct uptake of soil nitrogen by mosses.

    PubMed

    Ayres, Edward; van der Wal, René; Sommerkorn, Martin; Bardgett, Richard D

    2006-06-22

    Mosses are one of the most diverse and widespread groups of plants and often form the dominant vegetation in montane, boreal and arctic ecosystems. However, unlike higher plants, mosses lack developed root and vascular systems, which is thought to limit their access to soil nutrients. Here, we test the ability of two physiologically and taxonomically distinct moss species to take up soil- and wet deposition-derived nitrogen (N) in natural intact turfs using stable isotopic techniques (15N). Both species exhibited increased concentrations of shoot 15N when exposed to either soil- or wet deposition-derived 15N, demonstrating conclusively and for the first time, that mosses derive N from the soil. Given the broad physiological and taxonomic differences between these moss species, we suggest soil N uptake may be common among mosses, although further studies are required to test this prediction. Soil N uptake by moss species may allow them to compete for soil N in a wide range of ecosystems. Moreover, since many terrestrial ecosystems are N limited, soil N uptake by mosses may have implications for plant community structure and nutrient cycling. Finally, soil N uptake may place some moss species at greater risk from N pollution than previously appreciated.

  7. Implications of abnormal right ventricular thallium uptake in acute myocardial infarction

    SciTech Connect

    Nestico, P.F.; Hakki, A.H.; Felsher, J.; Heo, J.; Iskandrian, A.S.

    1986-08-01

    The correlates of abnormal right ventricular (RV) thallium uptake were examined in 116 patients with documented acute myocardial infarction (AMI) who underwent predischarge thallium-201 scintigraphy at rest, radionuclide angiography and 24-hour ambulatory electrocardiography. The patients were separated into 2 groups: patients group 1 (n = 31) had increased RV thallium uptake and those in group 2 (n = 85) had no such uptake. The 2 groups were comparable in age, type and site of AMI, peak creatine kinase level, systolic blood pressure and heart rate. However, compared with group 2, group 1 had a lower mean left ventricular (LV) ejection fraction (33 +/- 15% vs 39 +/- 14%, p less than 0.05), higher prevalence of increased lung thallium uptake (45% vs 22%, p less than 0.02), more extensive LV perfusion defects (4.4 +/- 2.9 vs 3.0 +/- 3.0 segments, p less than 0.03) and more complex ventricular arrhythmias (55% vs 35%, p less than 0.05). At a mean follow-up of 6 months, 17 patients (8 in group 1 and 9 in group 2) died from cardiac causes. Actuarial life-table analysis showed that the survival rate was better in group 2 than in group 1 (Mantel-Cox statistics = 4.62, p = 0.03). Thus, patients with AMI and abnormal RV thallium uptake have worse LV function, more complex ventricular arrhythmias and worse prognosis.

  8. Hardwood seeding root and nutrient parameters for a model of nutrient uptake.

    PubMed

    Kelly, J M; Scarbrough, J D; Mays, P A

    2001-01-01

    Use of mechanistic models is an increasingly accepted way to evaluate complex processes. The Barber-Cushman model provides a means to simulate nutrient uptake once information on root system characteristics, nutrient uptake, and soil nutrient supply are developed. Objectives of this study were to determine during a growing season: (i) root growth for 1-yr-old black cherry (Prunus serotina Ehrh.), northern red oak (Quercus rubra L.), and red maple (Acer rubrum L.) seedlings; (ii) net plant increase in N, P, K, Ca, and Mg; (iii) soil solution and solid phase nutrient concentrations; and (iv) the influence of root growth and soil nutrient supply changes on nutrient uptake using the Barber-Cushman model. Seedlings were grown in pots containing A horizon soil from two forest sites. Measurements were made on five occasions during the growing season. Root growth averaged 41.5 cm d-1 for red maple compared with 28.0 and 16.7 cm d-1 for cherry and oak, respectively. Seventy-five percent of root growth occurred at the end of the growing season. Total plant N showed the greatest change (25-58%) due to soil source. Model simulations underestimated observed uptake by 31 to 99%. A clear relationship between soil solution nutrient concentration and plant uptake, an important assumption of the model, was not observed. Results indicate care will need to be exercised in the development and use of root growth and nutrient supply values in mechanistic models. PMID:11285903

  9. DOC:NO3- ratios and NO3- uptake in forested headwater streams

    NASA Astrophysics Data System (ADS)

    Rodríguez-Cardona, Bianca; Wymore, Adam S.; McDowell, William H.

    2016-01-01

    The underlying mechanisms driving the coupled interactions between inorganic nitrogen uptake and dissolved organic matter are not well understood, particularly in surface waters. To determine the relationship between dissolved organic carbon (DOC) quantity and nitrate (NO3-) uptake kinetics in streams, we performed a series of NO3- Tracer Additions for Spiraling Curve Characterization experiments in four streams within the Lamprey River Watershed, New Hampshire, across a range in background DOC concentrations (1-8 mg C/L). Experiments were performed throughout the 2013 and 2014 growing seasons. Across streams and experimental dates, ambient uptake velocity (Vf) correlated positively with increasing DOC concentrations and DOC:NO3- ratios but was only weakly negatively associated with NO3- concentrations. Ambient NO3- Vf was unrelated to pH, light, temperature, dissolved oxygen, and Specific Ultraviolet Absorbance at 254 nm. Although there were general tendencies across the entire Lamprey River Watershed, individual sites behaved differently in their uptake kinetics. NO3- uptake dynamics in the Lamprey River Watershed are most strongly influenced by DOC concentrations rather than NO3- concentrations or physicochemical parameters, which have been identified as regional- to continental-scale drivers in previous research. Understanding the fundamental relationships between dissolved organic matter and inorganic nutrients will be important as global and climatic changes influence the delivery and production of DOC and NO3- in aquatic ecosystems.

  10. Effects of pH on uranium uptake and oxidative stress responses induced in Arabidopsis thaliana.

    PubMed

    Saenen, Eline; Horemans, Nele; Vanhoudt, Nathalie; Vandenhove, Hildegarde; Biermans, Geert; Van Hees, May; Wannijn, Jean; Vangronsveld, Jaco; Cuypers, Ann

    2013-09-01

    Uranium (U) causes oxidative stress in Arabidopsis thaliana plants grown at pH 5.5. However, U speciation and its toxicity strongly depend on environmental parameters, for example pH. It is unknown how different U species determine U uptake and translocation within plants and how they might affect the oxidative defense mechanisms of these plants. The present study analyzed U uptake and oxidative stress-related responses in A. thaliana (Columbia ecotype) under contrasted U chemical speciation conditions. The 18-d-old seedlings were exposed for 3 d to 25 µM U in a nutrient solution of which the pH was adjusted to 4.5, 5.5, 6.5, or 7.5. Results indicate that there is a different rate of U uptake and translocation at the different pHs, with high uptake and low translocation at low pH and lower uptake but higher translocation at high pH. After U exposure, an increased glutathione reductase activity and total glutathione concentration were observed in U-exposed roots, pointing toward an important role for glutathione in the root defense system against U either by chelation or by antioxidative defense mechanisms. In leaves, antioxidative defense mechanisms were activated on U exposure, indicated by increased superoxide dismutase and catalase activity. As it seems that U toxicity is influenced by pH, it is important to consider site-specific characteristics when making U risk assessments. PMID:23737149

  11. Uptake rates of thorium progeny in a semiarid environment.

    PubMed

    McClellan, Yvonne; August, Robert; Gosz, James; Gann, Steve; Parmenter, Robert; Nelson, Martin; Harper, Mark

    2003-01-01

    The release rates and transformation processes that influence the mobility, biological uptake, and transfer of radionuclides are essential to the assessment of the health effects in the food chain and ecosystem. This study examined concentrations of 222Th in both soil and vegetation at a closed military training site, Kirtland Air Force Base (KAFB), New Mexico. Brazilian sludge was intentionally introduced into the topsoil in the early 1960s to simulate nuclear weapon accidents. Soil (60) and vegetation (120) samples were collected from 1996 to 2000 and analyzed for radionuclides and progeny. High-resolution gamma-ray spectroscopy was used to determine radionuclide activities. The results indicate that the thorium progeny were the predominant contaminant in soil and vegetation. Concentration ratios (CRs) were calculated based on actinium levels. PMID:14535318

  12. Nutrient Uptake Kinetics in Two Virginia Estuaries

    NASA Astrophysics Data System (ADS)

    Henry, A.; Mulholland, M. R.; Bernhardt, P.; Watson, A. M.; Dias, R. F.

    2002-12-01

    Recently, there has been an increase in the occurrence and geographical range of blooms of the brown tide pelagophyte Aureococcus anophagefferens in coastal areas along the east coast of the USA. Brown tide blooms occur when concentrations of inorganic nutrients are low or at the limit of analytical detection and these organisms have been shown to use organic nitrogen for growth. Indeed, it has been suggested that A. anophagefferens, along with a variety of other species that form harmful algal blooms, have a preference for organic nitrogen and because organic nitrogen compounds also have carbon, it is thought that many bloom species may supplement photosynthetic carbon fixation with uptake of organic carbon. In order to better understand the nutritional preferences of bloom organisms, we investigated uptake kinetics for inorganic and organic nutrients in two Virginia waterways where harmful algal blooms frequently occur; the Rappahannock River, a Chesapeake Bay tributary that experiences blooms of dinoflagellates, and Chincoteague Bay, a coastal bay where there are seasonal brown tide blooms. We used stable isotopes (15N and 13C) to measure uptake kinetics for NH4+, urea, two amino acids, a dipeptide and glucose. During the Chincoteague Bay study, there was a bloom of A. anophagefferens (> 1,000,000 cells/ml), however, no blooms were encountered during the Rappahannock Study. Results suggest that brown tide bloom populations had higher affinities and uptake capacities for NH4+ and dipeptides and lower affinities and uptake capacities for urea and the two amino acids. In addition, it appeared that the organic substrates were used primarily as N sources.

  13. Carbonyl sulfide exchange in soils for better estimates of ecosystem carbon uptake

    NASA Astrophysics Data System (ADS)

    Whelan, Mary E.; Hilton, Timothy W.; Berry, Joseph A.; Berkelhammer, Max; Desai, Ankur R.; Campbell, J. Elliott

    2016-03-01

    Carbonyl sulfide (COS) measurements are one of the emerging tools to better quantify gross primary production (GPP), the largest flux in the global carbon cycle. COS is a gas with a similar structure to CO2; COS uptake is thought to be a proxy for GPP. However, soils are a potential source or sink of COS. This study presents a framework for understanding soil-COS interactions. Excluding wetlands, most of the few observations of isolated soils that have been made show small uptake of atmospheric COS. Recently, a series of studies at an agricultural site in the central United States found soil COS production under hot conditions an order of magnitude greater than fluxes at other sites. To investigate the extent of this phenomenon, soils were collected from five new sites and incubated in a variety of soil moisture and temperature states. We found that soils from a desert, an oak savannah, a deciduous forest, and a rainforest exhibited small COS fluxes, behavior resembling previous studies. However, soil from an agricultural site in Illinois, > 800 km away from the initial central US study site, demonstrated comparably large soil fluxes under similar conditions. These new data suggest that, for the most part, soil COS interaction is negligible compared to plant uptake of COS. We present a model that anticipates the large agricultural soil fluxes so that they may be taken into account. While COS air-monitoring data are consistent with the dominance of plant uptake, improved interpretation of these data should incorporate the soil flux parameterizations suggested here.

  14. Carbonyl sulfide exchange in soils for better estimates of ecosystem carbon uptake

    DOE PAGESBeta

    Whelan, Mary E.; Hilton, Timothy W.; Berry, Joseph A.; Berkelhammer, Max; Desai, Ankur R.; Campbell, J. Elliott

    2016-03-21

    Carbonyl sulfide (COS) measurements are one of the emerging tools to better quantify gross primary production (GPP), the largest flux in the global carbon cycle. COS is a gas with a similar structure to CO2; COS uptake is thought to be a proxy for GPP. However, soils are a potential source or sink of COS. This study presents a framework for understanding soil–COS interactions. Excluding wetlands, most of the few observations of isolated soils that have been made show small uptake of atmospheric COS. Recently, a series of studies at an agricultural site in the central United States found soilmore » COS production under hot conditions an order of magnitude greater than fluxes at other sites. To investigate the extent of this phenomenon, soils were collected from five new sites and incubated in a variety of soil moisture and temperature states. We found that soils from a desert, an oak savannah, a deciduous forest, and a rainforest exhibited small COS fluxes, behavior resembling previous studies. However, soil from an agricultural site in Illinois, >800 km away from the initial central US study site, demonstrated comparably large soil fluxes under similar conditions. These new data suggest that, for the most part, soil COS interaction is negligible compared to plant uptake of COS. We present a model that anticipates the large agricultural soil fluxes so that they may be taken into account. Furthermore, while COS air-monitoring data are consistent with the dominance of plant uptake, improved interpretation of these data should incorporate the soil flux parameterizations suggested here.« less

  15. Investigating phosphorus uptake in anoxic and sulfidic surface sediments with 33P radiotracer experiments

    NASA Astrophysics Data System (ADS)

    Dijkstra, Nikki; Kraal, Peter; Gonzalez, Santiago; Slomp, Caroline

    2016-04-01

    Phosphorus (P) is a key nutrient for marine organisms. Enhanced P availability in the water column can fuel algal blooms and the development of bottom water anoxia. Recently, it was suggested that micro-organisms in sediments overlain by anoxic and sulfidic bottom waters might take up dissolved P and form Fe(II)-P minerals, thereby enhancing P removal. In this study, we investigated the uptake of P in surface sediments with 33P radiotracer experiments. The sediments were recovered from the anoxic and sulfidic deep basin of the Black Sea and, for comparison, from the adjacent oxic shelf. Results suggest a very fast sedimentary uptake of 33P at all sites but in particular for sediments from the oxic shelf. At all sites, most 33P was sequestered in the citrate-dithionite-bicarbonate-(CDB)-extractable sediment P fraction. No significant differences with abiotic controls were observed, implying that micro-organisms were not directly involved in the P uptake. Whereas 33P uptake by the oxic shelf sediment was likely controlled by sorption of 33P to iron(Fe)-(oxyhydr)oxides, the nature of the CDB-extractable P fraction in the deep basin sediments remains unclear. We discuss whether authigenic formation of Fe(II)-P minerals or fast adsorption of P to calcites may explain our findings.

  16. Effects of ammonium and nitrate on nutrient uptake and activity of nitrogen assimilating enzymes in western hemlock

    SciTech Connect

    Knoepp, J.D.; Turner, D.P.; Tingey, D.T.

    1993-01-01

    Western hemlock seedlings were grown in nutrient solutions with ammonium, nitrate or ammonium plus nitrate as nitrogen sources. The objectives were to examine (1) possible selectivity for ammonium or nitrate as an N source, (2) the maintenance of charge balance during ammonium and nitrate uptake, and (3) the activity of the nitrogen assimilating enzymes, nitrate reductase, glutamine synthetase, and glutamine dehydrogenase, in relation to the uptake of different nitrogen sources. The uptake studies revealed that western hemlock takes up ammonium faster than nitrate and that ammonium partially inhibits nitrate uptake. Nitrate reductase activity varied with nitrate availability in root tissue, but showed no response in needles, indicating that most nitrate is reduced in the roots. Results indicate that western hemlock may be adapted to sites where NH(4+) is the predominate N source.

  17. Imipramine treatment differentially affects platelet /sup 3/H-imipramine binding and serotonin uptake in depressed patients

    SciTech Connect

    Suranyi-Cadotte, B.E.; Quirion, R.; Nair, N.P.V.; Lafaille, F.; Schwartz, G.

    1985-02-25

    Uptake of serotonin and /sup 3/H-imipramine binding in platelets of depressed patients were investigated simultaneously with changes in clinical state. Both V/sub max/ for serotonin uptake and B/sub max/ for /sup 3/H-imipramine binding were significantly lower in unmedicated depressed patients with respect to normal subjects. Successful treatment with imipramine led to a significant increase in B/sub max/ for /sup 3/H-imipramine binding, without significant change in V/sub max/ for serotonin uptake. B/sub max/ values increased to the normal range following complete, rather than partial clinical improvement. These data indicate that successful antidepressant treatment may increase the density of /sup 3/H-imipramine binding sites on platelets by a process which is independent of the uptake of serotonin. 29 references, 1 table.

  18. Comparing Measures of Fine Root Uptake by Mature Trees: Applications for Determining the Potential Impacts of Climate Change-Induced Soil Freezing on Nutrient Uptake by Sugar Maple and Red Spruce

    NASA Astrophysics Data System (ADS)

    Socci, A. M.; Templer, P. H.

    2008-12-01

    and the peak growing seasons. Rates of nutrient uptake by intact roots were significantly greater than rates of uptake by excised roots for both sugar maple and red spruce. Despite this difference, the patterns of NH4+ uptake compared to NO3- uptake were consistent across both methods. These results suggest that both means of measuring root nutrient uptake may be sufficient for comparing relative treatment effects across sites. However, the observed variation in magnitude suggests that caution must be taken in interpreting actual rates of uptake from either method.

  19. Value siting

    SciTech Connect

    Ferrar, T.A.; Howes, J.A.

    1995-02-01

    Finding an appropriate site is becoming an increasing challenge in building new power projects. One of the first orders of business in project development is identifying a site that offers the maximum spread between the cost of fuel and net power price. The collection of sites that exhibit an adequate spread - presenting a first-order, acceptable economic expectation - must now be subjected to an ever increasing number of political, societal, technical, and economic exclusion screens. The barriers can include cooling water constraints, community resistance, visual incompatibility, archaeological concerns and endangered species preservation issues. Most power siting difficulties can be substantially mitigated by gaining access to developed, but under-used sites, whose current owners are bound by circumstances - political or financial - that prevent them from using such locations. There are two such categories of sites: Utilities that have sites on which depreciated power production assets rest; and, The federal government, with numerous sites throughout the country, particularly military bases subject to closure under the Base Realignment and Closure (BRAC) proceedings. It is in the interests of developers, as well as consumers, investors and taxpayers, ti undertake a thorough examination of these overlooked pearls of opportunities and develop their potential.

  20. Characterization of (+/-)-methadone uptake by rat lung.

    PubMed Central

    Chi, C H; Dixit, B N

    1977-01-01

    1. By use of a sensitive and specific fluorescence assay procedure it was shown that after subcutaneous administration to rats, (+/-)-methadone was concentrated in the lung. Lung to serum ratios ranging from 25 to 60 were obtained indicating that the rat lung tissue was capable of extracting (+/-)-methadone against a concentration gradient. 2. This phenomenon was investigated in vitro with rat lung slices incubated in Krebs-Ringer phosphate buffer (pH 7.4). The uptake was expressed in terms of tissue to medium concentration ratios (T/M ratio). 3. The principal observations were: (i) Studies on the time-course of the uptake showed that the T/M ratios of (+/-)-methadone increased rapidly during the first 60 min of incubation and then more slowly, with a plateau occurring at 180 min; (ii) The T/M ratio of (+/-)-methadone progressively increased from 9.5 to 17 as the pH of the incubation medium was varied from 6.2 to 7.5; (iii) When the concentration of (+/-)-methadone in the incubation medium was varied from 0.005 to 0.5 mM, the T/M ratio decreased rapidly suggesting self-saturation of the transport process. Beyond the medium concentration of 0.5 mM, the T/M ratio declined very slowly. 4. These results suggested that at low concentrations, (+/-)-methadone was transported predominantly by a self-saturable process while at higher concentrations it was transported by a process of simple diffusion. 5. At low concentrations (0.01 mM) the uptake of (+)-methadone was higher than that of (-)-isomer indicating stereo-specificity of the uptake process. The uptake of (+/-)-methadone at low concentration (0.01 mM) was significantly inhibited by low temperature, lack of O2, lack of glucose, lack of Na+ in the incubation medium, and by exposure of the tissue to high temperature (approximately 100 degrees C). The uptake was also inhibited by relatively high concentration of iodoacetate (1.0 mM) and of naloxone (1.0 mM). 6. Kinetic analysis of data showed that the diffusion constant

  1. An exposure system for measuring nasal and lung uptake of vapors in rats

    SciTech Connect

    Dahl, A.R.; Brookins, L.K.; Gerde, P.

    1995-12-01

    Inhaled gases and vapors often produce biological damage in the nasal cavity and lower respiratory tract. The specific site within the respirator tract at which a gas or vapor is absorbed strongly influences the tissues at risk to potential toxic effects; to predict or to explain tissue or cell specific toxicity of inhaled gases or vapors, the sites at which they are absorbed must be known. The purpose of the work reported here was to develop a system for determining nose and lung absorption of vapors in rats, an animal commonly used in inhalation toxicity studies. In summary, the exposure system described allows us to measure in the rate: (1) nasal absorption and desorption of vapors; (2) net lung uptake of vapors; and (3) the effects of changed breathing parameters on vapor uptake.

  2. Stimulation of Cadmium Uptake in Relation to the Cadmium Content of Plants 1

    PubMed Central

    Petit, Charles M.; Ringoet, Arthur; Myttenaere, Constant

    1978-01-01

    The time course of cadmium uptake by the roots of intact tomato plants (Lycopersicon esculentum Mill.) was measured in a nutrient solution with a micromolar cadmium concentration until all cadmium in the medium was exhausted. Exhaustion taking a few hours, cadmium was repeatedly added to the nutrient solution. The initial rate of cadmium uptake was computed for each cadmium addition. This rate sharply increased and ultimately leveled off, the maximum value being about three times higher than the value measured after the first cadmium addition. The stimulating effect of cadmium was associated with an inhibitory effect at higher levels of cadmium concentrations. An increase in the net cadmium influx with time could not be explained by the binding of heavy metal to a fixed number of organic compounds. Conceivably, the production of binding sites could be increased and cadmium might play a part in controlling the rate of sites production. PMID:16660557

  3. Influence of the physicochemical characteristics of pollutants on their uptake in moss

    NASA Astrophysics Data System (ADS)

    Varela, Z.; Fernández, J. A.; Real, C.; Carballeira, A.; Aboal, J. R.

    2015-02-01

    Bryophytes are commonly used as biomonitors to estimate the atmospheric deposition of heavy metals and metalloids. However, the tissue concentrations of these elements in moss do not always accurately reflect atmospheric levels. The aim of the present study was to investigate whether element uptake in moss is affected by the physicochemical characteristics of the elements. Factor analysis was used to identify any patterns of covariance in the accumulation of elements in samples of the moss Pseudoscleropodium purum collected from the surroundings of different factories and from control sites. The variation in the concentrations of elements was similar in moss from both types of sites and was related to the binding properties of the elements. This suggests that the physicochemical characteristics of the elements determine the uptake of metals and metalloids from the atmosphere. Therefore, in studies that use multiple correlations among elements as indicators of a common origin of contaminants, erroneous conclusions may be reached by overlooking the adsorption properties of the moss.

  4. Gallium-68 PSMA uptake in adrenal adenoma.

    PubMed

    Law, W Phillip; Fiumara, Frank; Fong, William; Miles, Kenneth A

    2016-08-01

    Gallium-68 (Ga-68) labelled prostate-specific membrane antigen (PSMA) imaging by positron emission tomography (PET) has emerged as a promising tool for staging of prostate cancer and restaging of disease in recurrence or biochemical failure after definitive treatment of prostate cancer. Ga-68 PSMA PET produces high target-to-background images of prostate cancer and its metastases which are reflective of the significant overexpression of PSMA in these cells and greatly facilitates tumour detection. However, relatively little is known about the PSMA expression of benign neoplasms and non-prostate epithelial malignancies. This is a case report of PSMA uptake in an adrenal adenoma incidentally discovered on PET performed for restaging of biochemically suspected prostate cancer recurrence. With the increasing use of PSMA PET in the management of prostate cancer - and the not infrequent occurrence of adrenal adenomas - the appearance of low- to moderate-grade PSMA uptake in adrenal adenomas should be one with which reporting clinicians are familiar.

  5. Calcium Uptake in Crude Tissue Preparation.

    PubMed

    Bidwell, Philip A; Kranias, Evangelia G

    2016-01-01

    The various isoforms of the sarco/endoplasmic reticulum Ca(2+) ATPase (SERCA) are responsible for the Ca(2+) uptake from the cytosol into the endoplasmic or sarcoplasmic reticulum (ER/SR). In some tissues, the activity of SERCA can be modulated by binding partners, such as phospholamban and sarcolipin. The activity of SERCA can be characterized by its apparent affinity for Ca(2+) as well as maximal enzymatic velocity. Both parameters can be effectively determined by the protocol described here. Specifically, we describe the measurement of the rate of oxalate-facilitated (45)Ca uptake into the SR of crude mouse ventricular homogenates. This protocol can easily be adapted for different tissues and animal models as well as cultured cells.

  6. Computer program for calculation of oxygen uptake

    NASA Technical Reports Server (NTRS)

    Castle, B. L.; Castle, G.; Greenleaf, J. E.

    1979-01-01

    A description and operational precedures are presented for a computer program, written in Super Basic, that calculates oxygen uptake, carbon dioxide production, and related ventilation parameters. Program features include: (1) the option of entering slope and intercept values of calibration curves for the O2 and CO2 and analyzers; (2) calculation of expired water vapor pressure; and (3) the option of entering inspured O2 and CO2 concentrations. The program is easily adaptable for programmable laboratory calculators.

  7. Uranium uptake by hydroponically cultivated crop plants.

    PubMed

    Soudek, Petr; Petrová, Sárka; Benešová, Dagmar; Dvořáková, Marcela; Vaněk, Tomáš

    2011-06-01

    Hydroponicaly cultivated plants were grown on medium containing uranium. The appropriate concentrations of uranium for the experiments were selected on the basis of a standard ecotoxicity test. The most sensitive plant species was determined to be Lactuca sativa with an EC(50) value about 0.1mM. Cucumis sativa represented the most resistant plant to uranium (EC(50)=0.71 mM). Therefore, we used the uranium in a concentration range from 0.1 to 1mM. Twenty different plant species were tested in hydroponic solution supplemented by 0.1mM or 0.5mM uranium concentration. The uranium accumulation of these plants varied from 0.16 mg/g DW to 0.011 mg/g DW. The highest uranium uptake was determined for Zea mays and the lowest for Arabidopsis thaliana. The amount of accumulated uranium was strongly influenced by uranium concentration in the cultivation medium. Autoradiography showed that uranium is mainly localized in the root system of the plants tested. Additional experiments demonstrated the possibility of influencing the uranium uptake from the cultivation medium by amendments. Tartaric acid was able to increase uranium uptake by Brassica oleracea and Sinapis alba up to 2.8 times or 1.9 times, respectively. Phosphate deficiency increased uranium uptake up to 4.5 times or 3.9 times, respectively, by Brassica oleracea and S. alba. In the case of deficiency of iron or presence of cadmium ions we did not find any increase in uranium accumulation.

  8. Varicella vaccine uptake in Shandong province, China

    PubMed Central

    Xu, Aiqiang; Xu, Qing; Fang, Xueqiang; Bialek, Stephanie; Wang, Chengbin

    2012-01-01

    Varicella vaccine has been licensed in China for decade to be used as single dose in children aged ≥ 12 mo of age in private sector. Little data were available on varicella uptake to date in China yet. A cross-sectional study was conducted in Shandong Province in May 2011 to examine varicella vaccination coverage among children aged 16–40 mo and examine factors associated with varicella vaccine uptake. The overall coverage among children eligible for varicella vaccine was 62% (range 16.7–94.7% by county), much lower than the coverage of the eight vaccines included in the national immunization program (all above 97%). Though proximity to immunization services (< 5 km) was linked with higher vaccine uptake (62.6 vs. 37.4%, p = 0.02), county-level economic development (77.8, 61.0 and 47.1% for developed, sub-developed and developing regions, respectively, p < 0.001) played an even more important role in varicella vaccination. Moreover, there was little variation in coverage of vaccines included in the national immunization program along with county-level economic development. Even though varicella vaccine uptake is relatively high for use on a private basis, the vaccination coverage is not high enough to prevent epidemiology shift to adolescents and adults who are more prone to develop severe outcomes to varicella. Further enhancement on varicella vaccination coverage is necessary and inclusion to national immunization program seems to be a promising option for achieving and maintaining high coverage. PMID:22894966

  9. A thermodynamic formulation of root water uptake

    NASA Astrophysics Data System (ADS)

    Hildebrandt, A.; Kleidon, A.; Bechmann, M.

    2015-12-01

    By extracting bound water from the soil and lifting it to the canopy, root systems of vegetation perform work. Here we describe how the energetics involved in root water uptake can be quantified. The illustration is done using a simple, four-box model of the soil-root system to represent heterogeneity and a parameterization in which root water uptake is driven by the xylem potential of the plant with a fixed flux boundary condition. We use this approach to evaluate the effects of soil moisture heterogeneity and root system properties on the dissipative losses and export of energy involved in root water uptake. For this, we derive an expression that relates the energy export at the root collar to a sum of terms that reflect all fluxes and storage changes along the flow path in thermodynamic terms. We conclude that such a thermodynamic evaluation of root water uptake conveniently provides insights into the impediments of different processes along the entire flow path and explicitly accounting not only for the resistances along the flow path and those imposed by soil drying but especially the role of heterogenous soil water distribution. The results show that least energy needs to be exported and dissipative losses are minimized by a root system if it extracts water uniformly from the soil. This has implications for plant water relations in forests where canopies generate heterogenous input patterns. Our diagnostic in the energy domain should be useful in future model applications for quantifying how plants can evolve towards greater efficiency in their structure and function, particularly in heterogenous soil environments. Generally, this approach may help to better describe heterogeneous processes in the soil in a simple, yet physically-based way.

  10. 21 CFR 886.1670 - Ophthalmic isotope uptake probe.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Ophthalmic isotope uptake probe. 886.1670 Section... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1670 Ophthalmic isotope uptake probe. (a) Identification. An ophthalmic isotope uptake probe is an AC-powered device intended to...

  11. 21 CFR 886.1670 - Ophthalmic isotope uptake probe.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Ophthalmic isotope uptake probe. 886.1670 Section... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1670 Ophthalmic isotope uptake probe. (a) Identification. An ophthalmic isotope uptake probe is an AC-powered device intended to...

  12. 21 CFR 886.1670 - Ophthalmic isotope uptake probe.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic isotope uptake probe. 886.1670 Section... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1670 Ophthalmic isotope uptake probe. (a) Identification. An ophthalmic isotope uptake probe is an AC-powered device intended to...

  13. 21 CFR 886.1670 - Ophthalmic isotope uptake probe.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Ophthalmic isotope uptake probe. 886.1670 Section... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1670 Ophthalmic isotope uptake probe. (a) Identification. An ophthalmic isotope uptake probe is an AC-powered device intended to...

  14. 21 CFR 886.1670 - Ophthalmic isotope uptake probe.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Ophthalmic isotope uptake probe. 886.1670 Section... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1670 Ophthalmic isotope uptake probe. (a) Identification. An ophthalmic isotope uptake probe is an AC-powered device intended to...

  15. Uptake as a Mechanism to Promote Student Learning

    ERIC Educational Resources Information Center

    Bell, Clare Valerie

    2013-01-01

    This study is a descriptive examination of uptake that occurred during classroom discourse in 33 Algebra I classrooms in nine U.S. states. Uptake refers to the act of taking up mathematical comments, questions, and constructions as objects of discourse. Uptake is important because it can be used for scaffolding authentic opportunities to learn and…

  16. 21 CFR 868.1730 - Oxygen uptake computer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Oxygen uptake computer. 868.1730 Section 868.1730...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1730 Oxygen uptake computer. (a) Identification. An oxygen uptake computer is a device intended to compute the amount of oxygen consumed by...

  17. 21 CFR 868.1730 - Oxygen uptake computer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Oxygen uptake computer. 868.1730 Section 868.1730...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1730 Oxygen uptake computer. (a) Identification. An oxygen uptake computer is a device intended to compute the amount of oxygen consumed by...

  18. 21 CFR 868.1730 - Oxygen uptake computer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Oxygen uptake computer. 868.1730 Section 868.1730...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1730 Oxygen uptake computer. (a) Identification. An oxygen uptake computer is a device intended to compute the amount of oxygen consumed by...

  19. 21 CFR 868.1730 - Oxygen uptake computer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Oxygen uptake computer. 868.1730 Section 868.1730...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1730 Oxygen uptake computer. (a) Identification. An oxygen uptake computer is a device intended to compute the amount of oxygen consumed by...

  20. 21 CFR 868.1730 - Oxygen uptake computer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Oxygen uptake computer. 868.1730 Section 868.1730...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1730 Oxygen uptake computer. (a) Identification. An oxygen uptake computer is a device intended to compute the amount of oxygen consumed by...

  1. Capturing Individual Uptake: Toward a Disruptive Research Methodology

    ERIC Educational Resources Information Center

    Bastian, Heather

    2015-01-01

    This article presents and illustrates a qualitative research methodology for studies of uptake. It does so by articulating a theoretical framework for qualitative investigations of uptake and detailing a research study designed to invoke and capture students' uptakes in a first-year writing classroom. The research design sought to make uptake…

  2. 21 CFR 892.1320 - Nuclear uptake probe.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Nuclear uptake probe. 892.1320 Section 892.1320...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1320 Nuclear uptake probe. (a) Identification. A nuclear uptake probe is a device intended to measure the amount of radionuclide taken up by...

  3. 21 CFR 892.1320 - Nuclear uptake probe.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Nuclear uptake probe. 892.1320 Section 892.1320...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1320 Nuclear uptake probe. (a) Identification. A nuclear uptake probe is a device intended to measure the amount of radionuclide taken up by...

  4. 21 CFR 892.1320 - Nuclear uptake probe.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nuclear uptake probe. 892.1320 Section 892.1320...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1320 Nuclear uptake probe. (a) Identification. A nuclear uptake probe is a device intended to measure the amount of radionuclide taken up by...

  5. 21 CFR 892.1320 - Nuclear uptake probe.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Nuclear uptake probe. 892.1320 Section 892.1320...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1320 Nuclear uptake probe. (a) Identification. A nuclear uptake probe is a device intended to measure the amount of radionuclide taken up by...

  6. 21 CFR 892.1320 - Nuclear uptake probe.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Nuclear uptake probe. 892.1320 Section 892.1320...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1320 Nuclear uptake probe. (a) Identification. A nuclear uptake probe is a device intended to measure the amount of radionuclide taken up by...

  7. Spatial analysis of agri-environmental policy uptake and expenditure in Scotland.

    PubMed

    Yang, Anastasia L; Rounsevell, Mark D A; Wilson, Ronald M; Haggett, Claire

    2014-01-15

    Agri-environment is one of the most widely supported rural development policy measures in Scotland in terms of number of participants and expenditure. It comprises 69 management options and sub-options that are delivered primarily through the competitive 'Rural Priorities scheme'. Understanding the spatial determinants of uptake and expenditure would assist policy-makers in guiding future policy targeting efforts for the rural environment. This study is unique in examining the spatial dependency and determinants of Scotland's agri-environmental measures and categorised options uptake and payments at the parish level. Spatial econometrics is applied to test the influence of 40 explanatory variables on farming characteristics, land capability, designated sites, accessibility and population. Results identified spatial dependency for each of the dependent variables, which supported the use of spatially-explicit models. The goodness of fit of the spatial models was better than for the aspatial regression models. There was also notable improvement in the models for participation compared with the models for expenditure. Furthermore a range of expected explanatory variables were found to be significant and varied according to the dependent variable used. The majority of models for both payment and uptake showed a significant positive relationship with SSSI (Sites of Special Scientific Interest), which are designated sites prioritised in Scottish policy. These results indicate that environmental targeting efforts by the government for AEP uptake in designated sites can be effective. However habitats outside of SSSI, termed here the 'wider countryside' may not be sufficiently competitive to receive funding in the current policy system.

  8. PARTITIONING THE RELATIVE INFLUENCE OF SOIL N, MYCORRHIZAE, AND FOLIAR N UPTAKE ON FOLIAR δ15N PATTERNS: CAN WE DETECT FOLIAR UPTAKE OF REACTIVE N?

    NASA Astrophysics Data System (ADS)

    Vallano, D.; Sparks, J. P.

    2009-12-01

    Vegetation is an important sink for atmospheric reactive N in N-limited systems and may be capable of incorporating reactive N compounds directly into leaves through the foliar uptake pathway. A proxy for atmospheric reactive N entering vegetation would be useful to estimate the impact of direct foliar N uptake on plant metabolism. Natural abundance foliar N isotopic composition (δ15N) is a practical tool for this purpose because plant-available N sources often have different isotopic compositions. Current understanding of foliar δ15N suggests these values primarily represent the integration of soil δ15N, direct foliar N uptake, mycorrhizal fractionation, and within-plant fractionations. Using a potted plant mesocosm system, we estimated the influence of mycorrhizae on foliar δ15N patterns in red maple (Acer rubrum) seedlings along an N deposition gradient in New York State. We found that mycorrhizal associations altered foliar δ15N in red maple seedlings from 0.03 - 1.01‰ across sites. Along the same temporal and spatial scales, we examined the influence of soil δ15N, foliar N uptake, and mycorrhizae on foliar δ15N in adult stands of American beech (Fagus grandifolia), black birch (Betula lenta), red maple (A. rubrum), and red oak (Quercus rubra). Using multiple regression models, atmospheric NO2 concentration explained 0%, 69%, 23%, and 45% of the residual variation in foliar δ15N remaining in American beech, red maple, red oak, and black birch, respectively, after accounting for soil δ15N. Our results suggest that foliar δ15N may be used to estimate pollution-derived atmospheric reactive N entering vegetation via the foliar N uptake pathway.

  9. Arsenic uptake and metabolism in plants.

    PubMed

    Zhao, F J; Ma, J F; Meharg, A A; McGrath, S P

    2009-03-01

    Arsenic (As) is an element that is nonessential for and toxic to plants. Arsenic contamination in the environment occurs in many regions, and, depending on environmental factors, its accumulation in food crops may pose a health risk to humans.Recent progress in understanding the mechanisms of As uptake and metabolism in plants is reviewed here. Arsenate is taken up by phosphate transporters. A number of the aquaporin nodulin26-like intrinsic proteins (NIPs) are able to transport arsenite,the predominant form of As in reducing environments. In rice (Oryza sativa), arsenite uptake shares the highly efficient silicon (Si) pathway of entry to root cells and efflux towards the xylem. In root cells arsenate is rapidly reduced to arsenite, which is effluxed to the external medium, complexed by thiol peptides or translocated to shoots. One type of arsenate reductase has been identified, but its in planta functions remain to be investigated. Some fern species in the Pteridaceae family are able to hyperaccumulate As in above-ground tissues. Hyperaccumulation appears to involve enhanced arsenate uptake, decreased arsenite-thiol complexation and arsenite efflux to the external medium, greatly enhanced xylem translocation of arsenite, and vacuolar sequestration of arsenite in fronds. Current knowledge gaps and future research directions are also identified. PMID:19207683

  10. A thermodynamic formulation of root water uptake

    NASA Astrophysics Data System (ADS)

    Hildebrandt, Anke; Kleidon, Axel; Bechmann, Marcel

    2016-08-01

    By extracting bound water from the soil and lifting it to the canopy, root systems of vegetation perform work. Here we describe how root water uptake can be evaluated thermodynamically and demonstrate that this evaluation provides additional insights into the factors that impede root water uptake. We derive an expression that relates the energy export at the base of the root system to a sum of terms that reflect all fluxes and storage changes along the flow path in thermodynamic terms. We illustrate this thermodynamic formulation using an idealized setup of scenarios with a simple model. In these scenarios, we demonstrate why heterogeneity in soil water distribution and rooting properties affect the impediment of water flow even though the mean soil water content and rooting properties are the same across the scenarios. The effects of heterogeneity can clearly be identified in the thermodynamics of the system in terms of differences in dissipative losses and hydraulic energy, resulting in an earlier start of water limitation in the drying cycle. We conclude that this thermodynamic evaluation of root water uptake conveniently provides insights into the impediments of different processes along the entire flow path, which goes beyond resistances and also accounts for the role of heterogeneity in soil water distribution.

  11. Arsenic uptake and metabolism in plants.

    PubMed

    Zhao, F J; Ma, J F; Meharg, A A; McGrath, S P

    2009-03-01

    Arsenic (As) is an element that is nonessential for and toxic to plants. Arsenic contamination in the environment occurs in many regions, and, depending on environmental factors, its accumulation in food crops may pose a health risk to humans.Recent progress in understanding the mechanisms of As uptake and metabolism in plants is reviewed here. Arsenate is taken up by phosphate transporters. A number of the aquaporin nodulin26-like intrinsic proteins (NIPs) are able to transport arsenite,the predominant form of As in reducing environments. In rice (Oryza sativa), arsenite uptake shares the highly efficient silicon (Si) pathway of entry to root cells and efflux towards the xylem. In root cells arsenate is rapidly reduced to arsenite, which is effluxed to the external medium, complexed by thiol peptides or translocated to shoots. One type of arsenate reductase has been identified, but its in planta functions remain to be investigated. Some fern species in the Pteridaceae family are able to hyperaccumulate As in above-ground tissues. Hyperaccumulation appears to involve enhanced arsenate uptake, decreased arsenite-thiol complexation and arsenite efflux to the external medium, greatly enhanced xylem translocation of arsenite, and vacuolar sequestration of arsenite in fronds. Current knowledge gaps and future research directions are also identified.

  12. Modeling carbon monoxide uptake during work

    SciTech Connect

    Bernard, T.E.; Duker, J.

    1981-05-01

    Acute carbon monoxide poisoning is the result of a diminished capacity of the blood to transport oxygen and sustain a level of metabolic activity. The diminished capacity is expressed in terms of the carboxyhemoglobin (COHb) level in the blood which is dependent upon the concentration of CO in the inhaled air. The rate of CO uptake or elimination is dependent upon the concentration of CO in the air as well as pulmonary diffusion capacity and alveolar ventilation which change with different metabolic rates. Coburn, Forster, and Kane (CFK) developed a mathematical model to describe the uptake and elimination kinetics of CO in sedentary individuals. The CFK model was used in a mathematical simulation of CO uptake and elimination where the independent variables were inhaled CO concentration and metabolic rate. The metabolic rate was used to specify pulmonary diffusing capacity and alveolar ventilation. As the level of COHb increased the metabolic rate was decreased to a level compatible with the impaired oxygen transport. A physical fatigue limit was also included. The theoretical model was used to simulate conditions beyond the range of exposures permissible under experimental laboratory conditions.

  13. Water Uptake in PEMFC Catalyst Layers

    SciTech Connect

    Gunterman, Haluna P.; Kwong, Anthony H.; Gostick, Jeffrey T.; Kusoglu, Ahmet; Weber, Adam Z.

    2011-07-01

    Water uptake profiles of proton-exchange-membrane fuel-cell catalyst layers are characterized in the form of capillary-pressure saturation (Pc-S) curves. The curves indicate that the catalyst layers tested are highly hydrophilic and require capillary pressures as low as -80 kPa to eject imbibed water. Comparison of materials made with and without Pt indicates a difference in water ejection and uptake phenomena due to the presence of Pt. The addition of Pt increases the tendency of the catalyst layer to retain water. Dynamic vapor sorption (DVS) is used to characterize the water-vapor sorption onto Nafion, Pt/C, and C surfaces. The DVS results align with the trends found from the Pc-S curves and show an increased propensity for water uptake in the presence of Pt. The effect of the ion in Nafion, sodium or protonated form, is also compared and demonstrates that although the protonation of the Nafion in the catalyst layer also increases hydrophilicity, the effect is not as great as that caused by Pt.

  14. Cloning, expression, and characterization of cadmium and manganese uptake genes from Lactobacillus plantarum

    SciTech Connect

    Hao, Z.; Chen, S.; Wilson, D.B.

    1999-11-01

    An Mn{sup 2+} and Cd{sup 2+} uptake gene, mntA, was cloned from Lactobacillus plantarum ATCC 14917 into Escherichia coli. Its expression conferred on E. coli cells increased Cd{sup 2+} sensitivity as well as energy-dependent Cd{sup 2+} uptake activity. Both transcription and translation of mntA were induced by Mn{sup 2+} starvation in L. plantarum, as indicated by reverse transcriptase PCR and immunoblotting. Two Cd{sup 2+} uptake systems have been identified in L. plantarum: one is a high-affinity Mn{sup 2+} and Cd{sup 2+} uptake system that is expressed in Mn{sup 2+}-starved cells, and the other is a nonsaturable Cd{sup 2+} uptake system that is expressed in Cd{sup 2+}-sufficient cells. MntA was not detected in an Mn{sup 2+}-dependent mutant of L. plantarum which had lost high-affinity Mn{sup 2+} and Cd{sup 2+} uptake activity. The results suggest that mntA is the gene encoding the high-affinity Mn{sup 2+} and Cd{sup 2+} transporter. On the basis of its predicted amino acid sequence, MntA belongs to the family of P-type cation-translocating ATPases. The topology and potential Mn{sup 2+}- and Cd{sup 2+}-binding sites of MntA are discussed. A second clone containing a low-affinity Cd{sup 2+} transport system was also isolated.

  15. Nitrogen deposition and prey nitrogen uptake control the nutrition of the carnivorous plant Drosera rotundifolia.

    PubMed

    Millett, J; Foot, G W; Svensson, B M

    2015-04-15

    Nitrogen (N) deposition has important negative impacts on natural and semi-natural ecosystems, impacting on biotic interactions across trophic levels. Low-nutrient systems are particularly sensitive to changes in N inputs and are therefore more vulnerable to N deposition. Carnivorous plants are often part of these ecosystems partly because of the additional nutrients obtained from prey. We studied the impact of N deposition on the nutrition of the carnivorous plant Drosera rotundifolia growing on 16 ombrotrophic bogs across Europe. We measured tissue N, phosphorus (P) and potassium (K) concentrations and prey and root N uptake using a natural abundance stable isotope approach. Our aim was to test the impact of N deposition on D. rotundifolia prey and root N uptake, and nutrient stoichiometry. D. rotundifolia root N uptake was strongly affected by N deposition, possibly resulting in reduced N limitation. The contribution of prey N to the N contained in D. rotundifolia ranged from 20 to 60%. N deposition reduced the maximum amount of N derived from prey, but this varied below this maximum. D. rotundifolia tissue N concentrations were a product of both root N availability and prey N uptake. Increased prey N uptake was correlated with increased tissue P concentrations indicating uptake of P from prey. N deposition therefore reduced the strength of a carnivorous plant-prey interaction, resulting in a reduction in nutrient transfer between trophic levels. We suggest that N deposition has a negative impact on D. rotundifolia and that responses to N deposition might be strongly site specific. PMID:25655989

  16. Sodium-Glucose Transporter-2 (SGLT2; SLC5A2) Enhances Cellular Uptake of Aminoglycosides

    PubMed Central

    Jiang, Meiyan; Wang, Qi; Karasawa, Takatoshi; Koo, Ja-Won; Li, Hongzhe; Steyger, Peter S.

    2014-01-01

    Aminoglycoside antibiotics, like gentamicin, continue to be clinically essential worldwide to treat life-threatening bacterial infections. Yet, the ototoxic and nephrotoxic side-effects of these drugs remain serious complications. A major site of gentamicin uptake and toxicity resides within kidney proximal tubules that also heavily express electrogenic sodium-glucose transporter-2 (SGLT2; SLC5A2) in vivo. We hypothesized that SGLT2 traffics gentamicin, and promotes cellular toxicity. We confirmed in vitro expression of SGLT2 in proximal tubule-derived KPT2 cells, and absence in distal tubule-derived KDT3 cells. D-glucose competitively decreased the uptake of 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose (2-NBDG), a fluorescent analog of glucose, and fluorescently-tagged gentamicin (GTTR) by KPT2 cells. Phlorizin, an SGLT2 antagonist, strongly inhibited uptake of 2-NBDG and GTTR by KPT2 cells in a dose- and time-dependent manner. GTTR uptake was elevated in KDT3 cells transfected with SGLT2 (compared to controls); and this enhanced uptake was attenuated by phlorizin. Knock-down of SGLT2 expression by siRNA reduced gentamicin-induced cytotoxicity. In vivo, SGLT2 was robustly expressed in kidney proximal tubule cells of heterozygous, but not null, mice. Phlorizin decreased GTTR uptake by kidney proximal tubule cells in Sglt2+/− mice, but not in Sglt2−/− mice. However, serum GTTR levels were elevated in Sglt2−/− mice compared to Sglt2+/− mice, and in phlorizin-treated Sglt2+/− mice compared to vehicle-treated Sglt2+/− mice. Loss of SGLT2 function by antagonism or by gene deletion did not affect gentamicin cochlear loading or auditory function. Phlorizin did not protect wild-type mice from kanamycin-induced ototoxicity. We conclude that SGLT2 can traffic gentamicin and contribute to gentamicin-induced cytotoxicity. PMID:25268124

  17. Computational screening of iodine uptake in zeolitic imidazolate frameworks in a water-containing system.

    PubMed

    Yuan, Yue; Dong, Xiuqin; Chen, Yifei; Zhang, Minhua

    2016-08-17

    Iodine capture is of great environmental significance due to the high toxicity and volatility of I2. Here we conduct a systematic computational investigation of iodine adsorption in zeolitic imidazolate frameworks (ZIFs) by adopting the grand canonical Monte Carlo (GCMC) simulation and the density functional theory (DFT) method. The results confirm the vital structural factors for iodine adsorption at 298 K and moderate pressures including metal sites, organic linkers, symmetry, and topology types. The uptake will be enhanced by active metal sites, the simple imidazolate linker and single asymmetric linkers with polar functional groups. The symmetry effect is stronger than the surface properties. Meanwhile low steric hindrance is more beneficial than polar functional groups to iodine adsorption. The specific topology types like mer bringing large surface areas and large diameter cages result in high iodine capacities. Iodine molecules tend to locate in cages with large diameters and aggregates along the sides of cages. In contrast, water prefers small diameter cages. In hydrophilic materials, water has a negative impact on iodine uptake due to its similar adsorption sites to iodine. The selectivity of iodine over water increases with increasing water content due to the large diameter cages of ZIFs. This work proves that ZIFs can be identified as efficient and economical adsorbents with high diversity for iodine in a water-containing system. Furthermore, it provides comprehensive insights into key structural factors for iodine uptake and separation in silver-free porous solids. PMID:27499079

  18. Modelling water uptake efficiency of root systems

    NASA Astrophysics Data System (ADS)

    Leitner, Daniel; Tron, Stefania; Schröder, Natalie; Bodner, Gernot; Javaux, Mathieu; Vanderborght, Jan; Vereecken, Harry; Schnepf, Andrea

    2016-04-01

    Water uptake is crucial for plant productivity. Trait based breeding for more water efficient crops will enable a sustainable agricultural management under specific pedoclimatic conditions, and can increase drought resistance of plants. Mathematical modelling can be used to find suitable root system traits for better water uptake efficiency defined as amount of water taken up per unit of root biomass. This approach requires large simulation times and large number of simulation runs, since we test different root systems under different pedoclimatic conditions. In this work, we model water movement by the 1-dimensional Richards equation with the soil hydraulic properties described according to the van Genuchten model. Climatic conditions serve as the upper boundary condition. The root system grows during the simulation period and water uptake is calculated via a sink term (after Tron et al. 2015). The goal of this work is to compare different free software tools based on different numerical schemes to solve the model. We compare implementations using DUMUX (based on finite volumes), Hydrus 1D (based on finite elements), and a Matlab implementation of Van Dam, J. C., & Feddes 2000 (based on finite differences). We analyse the methods for accuracy, speed and flexibility. Using this model case study, we can clearly show the impact of various root system traits on water uptake efficiency. Furthermore, we can quantify frequent simplifications that are introduced in the modelling step like considering a static root system instead of a growing one, or considering a sink term based on root density instead of considering the full root hydraulic model (Javaux et al. 2008). References Tron, S., Bodner, G., Laio, F., Ridolfi, L., & Leitner, D. (2015). Can diversity in root architecture explain plant water use efficiency? A modeling study. Ecological modelling, 312, 200-210. Van Dam, J. C., & Feddes, R. A. (2000). Numerical simulation of infiltration, evaporation and shallow

  19. Repetitive mechanical strain suppresses macrophage uptake of immunoglobulin G complexes and enhances cyclic adenosine monophosphate synthesis.

    PubMed Central

    Mattana, J.; Sankaran, R. T.; Singhal, P. C.

    1995-01-01

    Uptake of immunoglobulin G (IgG) complexes by macrophages (M phi) may play an important role in disease states characterized by increased levels of circulating immune complexes. In sites such as the glomerular mesangium M phi may be subjected to repetitive mechanical strain, although in vitro studies of M phi endocytosis are typically carried out with cells grown on rigid surfaces. We undertook the present study to determine whether repetitive mechanical strain could modulate M phi endocytosis of IgG complexes. IgG complex uptake was significantly diminished in M phi that were subjected to repetitive mechanical strain using parameters corresponding to peak and minimal intraglomerular pressures compared with control, and uptake varied according to the amount of mechanical strain applied. There was no significant difference in surface binding of IgG between M phi subjected to strain and those not. Mechanical strain did not significantly influence the rate of IgG complex degradation. Inhibition of nitric oxide synthase and guanylate cyclase activity did not alter the effect of mechanical strain, although this effect was potentiated by 3-isobutyl-1-methylxanthine (IBMX). Angiotensin II, which has been shown to reduce adenosine 3',5'-cyclic monophosphate (cAMP) production in M phi, significantly attenuated the suppressive effect of mechanical strain on IgG complex uptake as well as another inhibitor of cAMP generation, indomethacin. Enzyme immunoassay demonstrated significantly enhanced levels of cAMP in M phi that were subjected to mechanical strain compared with control, an effect that was potentiated by IBMX and attenuated by angiotensin II and indomethacin. These results demonstrate that repetitive mechanical strain significantly reduces IgG complex uptake by M phi, most likely by enhancing cAMP synthesis. Such an effect might play a significant role in macromolecule handling by M phi in sites in which they are subjected to repetitive mechanical deformation such as

  20. Foliar concentrations of volunteer willows growing on polluted sediment-derived sites versus sites with baseline contamination levels.

    PubMed

    Vandecasteele, Bart; Quataert, Paul; De Vos, Bruno; Tack, Filip M G; Muys, Bart

    2004-04-01

    Many alluvial soils along navigable waterways are affected by disposal of dredged sediments or overbank sedimentation and contain metal concentrations that are elevated compared to baseline levels. Uptake patterns for metals and other elements by several volunteer Salix species growing on these sites were determined during a growing season in field plots and compared with the same species growing on soils with baseline contamination levels. For Cd and Zn, foliar concentrations were clearly higher on dredged sediment landfills. Uptake patterns differed significantly between species. A high uptake of Mn and low uptake of Cu, K and S in S. cinerea was attributed to wetland soil chemistry. Site effects on metal uptake were evaluated in more detail for Salix cinerea and S. alba growing on different sediment-derived sites under field conditions. Foliar Cd concentrations were higher in S. cinerea than in S. alba. This appeared to be a genetic feature not influenced by soil chemical properties, as it was observed both on clean sites and polluted sediment-derived sites. For S. cinerea, soil chemistry was reflected in foliar concentrations, while foliar Cd concentrations and bioavailability were found to be independent of the thickness of the polluted horizon. Dredged sediment landfills and freshwater tidal marshes with comparable Cd soil pollution had significantly different foliar Cd concentrations.

  1. Monitoring vegetation water uptake in a semiarid riparian corridor

    NASA Astrophysics Data System (ADS)

    Robinson, J.; Ochoa, C. G.; Leonard, J.

    2015-12-01

    With a changing global climate and growing demand for water throughout the world, responsible and sustainable land and water resource management practices are becoming increasingly important. Accounting for the amount of water used by riparian vegetation is a critical element for better managing water resources in arid and semiarid environments. The objective of this study was to determine water uptake by selected riparian vegetative species in a semiarid riparian corridor in North-Central Oregon. Exo-skin sap flow sensors (Dynamax, Houston, TX, U.S.A.) were used to measure sap flux in red alder (Alnus rubra) trees, the dominant overstory vegetation at the field site. Xylem sap flow data was collected from selected trees at the field site and in a greenhouse setting. Transpiration rates were determined based on an energy balance method, which makes it possible to estimate the mass flow of sap by measuring the velocity of electrical heat pulses through the plant stem. Preliminary field results indicate that red alder tree branches of about 1 inch diameter transpire between 2 and 6 kg of water/day. Higher transpiration rates of up to 7.3 kg of water/day were observed under greenhouse conditions. Streamflow and stream water temperature, vegetation characteristics, and meteorological data were analyzed in conjunction with transpiration data. Results of this study provide insight on riparian vegetation water consumption in water scarce ecosystems. This study is part of an overarching project focused on climate-vegetation interactions and ecohydrologic processes in arid and semiarid landscapes.

  2. Modeling vapor uptake induced mobility shifts in peptide ions observed with transversal modulation ion mobility spectrometry-mass spectrometry.

    PubMed

    Rawat, Vivek K; Vidal-de-Miguel, Guillermo; Hogan, Christopher J

    2015-10-21

    Low field ion mobility spectrometry-mass spectrometry (IMS-MS) techniques exhibit low orthogonality, as inverse mobility often scales with mass to charge ratio. This inadequacy can be mitigated by adding vapor dopants, which may cluster with analyte ions and shift their mobilities by amounts independent of both mass and mobility of the ion. It is therefore important to understand the interactions of vapor dopants with ions, to better quantify the extent of dopant facilitated mobility shifts. Here, we develop predictive models of vapor dopant facilitated mobility shifts, and compare model calculations to measurements of mobility shifts for peptide ions exposed to variable gas phase concentrations of isopropanol. Mobility measurements were made at atmospheric pressure and room temperature using a recently developed transversal modulation ion mobility spectrometer (TMIMS). Results are compared to three separate models, wherein mobility shifts due to vapor dopants are attributed to changes in gas composition and (I) no vapor dopant uptake is assumed, (II) site-specific dopant uptake by the ion is assumed (approximated via a Langmuir adsorption model), and (III) site-unspecific dopant uptake by the ion is assumed (approximated via a classical nucleation model). We find that mobility shifts in peptide ions are in excellent agreement with model II, site-specific binding predictions. Conversely, mobility shifts of tetraalkylammonium ions from previous measurements were compared with these models and best agreement was found with model III predictions, i.e. site-unspecific dopant uptake.

  3. Focal 99mTc-DMSA Uptake in Lung Parenchyma Without Structural Alterations on SPECT/CT.

    PubMed

    Nursal, Gül Nihal; Reyhan, Mehmet; Yapar, Ali Fuat

    2015-11-01

    Static renal scintigraphy with Tc-DMSA is commonly used for the evaluation of renal morphology and function. Extrarenal uptake of Tc-DMSA is a rare finding described previously on sites such as bone metastasis, hemangioma, and splenic amyloidosis. We report a case with Tc-DMSA activity in the lungs.

  4. Modeling of cellular arginine uptake by more than one transporter.

    PubMed

    Nel, Marietha J; Woodiwiss, Angela J; Candy, Geoffrey P

    2012-01-01

    Determining the kinetic constants of arginine uptake by endothelial cells mediated by more than one transporter from linearization of data as Eadie-Hofstee plots or modeling which does not include the concentration of trace radiolabeled amino acid used to measure uptake may not be correct. The initial rate of uptake of trace [³H]L-arginine by HUVECs and ECV₃₀₄ cells in the presence of a range of unlabeled arginine and modifiers was used in nonlinear models to calculate the constants of arginine uptake using GraphPad Prism. Theoretical plots of uptake derived from constants determined from Eadie-Hofstee graphs overestimated uptake, whereas those from the nonlinear modeling approach agreed with experimental data. The contribution of uptake by individual transporters could be modeled and showed that leucine inhibited the individual transporters differently and not necessarily competitively. N-Ethylmaleimide inhibited only y⁺ transport, and BCH may be a selective inhibitor of y⁺L transport. The absence of sodium reduced arginine uptake by y⁺L transport and reduced the K(m)', whereas reducing sodium decreased arginine uptake by y⁺ transport without affecting the K (m)'. The nonlinear modeling approach using raw data avoided the errors inherent in methods deriving constants from the linearization of the uptake processes following Michaelian kinetics. This study provides explanations for discrepancies in the literature and suggests that a nonlinear modeling approach better characterizes the kinetics of amino acid uptake into cells by more than one transporter.

  5. Relating Nutrient Uptake And Respiration With Metabolically Active Transient Storage

    NASA Astrophysics Data System (ADS)

    Argerich, A.; Haggerty, R.; Christensen, C.

    2009-12-01

    Quantification of water transient storage zones is critical to understand stream nutrient uptake, but the common method to measure transient storage parameters (based on the use of conservative solutes as hydrologic tracers) does not allow distinguishing among different transient storage compartments that contribute in different proportions to nutrient uptake. We use an alternative experimental approach, the Resazurin (Raz) “smart” tracer, which in combination with a conservative tracer is expected to give the relation between metabolically active transient storage (MATS) versus whole transient storage. Raz is a weakly fluorescent phenoxazine dye that undergoes an irreversible reduction to highly fluorescent Resorufin (hereafter referred as Rru) in the presence of aerobic respiration. We conducted a combined injection of Raz, NaCl, NH4, and PO4 in WS01 at H.J. Andrews Experimental Forest. The injection was performed during low-baseflow conditions (Q<0.5 L/s) at a constant flow rate for 5 days. Changes in time in EC, Raz, Rru and nutrient concentrations were examined at 3 surface sampling sites and at 6 wells. Simultaneously to the injection we measured whole-reach metabolism and we performed an SF6 injection to measure the exchange coefficient of O2 between the atmosphere and stream water. The reach achieved plateau conditions in less than 15 hours after the injection began and recovered to pre-injection conditions 56 hours after the end of the injection. EC corrected by background conditions decreased with distance reflecting a dilution effect caused by the water gaining condition of the reach. Raz concentration increased and Rru concentration decreased along the reach reflecting the transformation of Raz to Rru with distance. The Rru to Raz ratio at surface water was correlated with instantaneous rates of net ecosystem production (NEP) measured over the whole reach. Percentage of surface water in wells during plateau ranged between 50% and 95%. Raz

  6. Antihistamine effect on synaptosomal uptake of serotonin, norepinephrine and dopamine

    NASA Technical Reports Server (NTRS)

    Brown, P. A.; Vernikos, J.

    1980-01-01

    A study on the effects of five H1 and H2 antihistamines on the synaptosomal uptake of serotonin (5HT), norepinephrine (NE), and dopamine (DA) is presented. Brain homogenates from female rats were incubated in Krebs-Ringer phosphate buffer solution in the presence of one of three radioactive neurotransmitters, and one of the five antihistamines. Low concentrations of pyrilamine competitively inhibited 5HT uptake, had little effect on NE uptake, and no effect on DA uptake. Promethazine, diphenhydramine, metiamide, and cimetidine had no effect on 5HT or DA uptake at the same concentration. Diphenhydramine had a small inhibitory effect on NE uptake. It is concluded that pyrilamine is a selective and potent competitive inhibitor of 5HT uptake at concentrations between .05 and .5 micromolars.

  7. Effects of calmodulin and calmodulin inhibitors on Ca uptake by sarcoplasmic reticulum of saponin skinned caudal artery

    SciTech Connect

    Stout, M.A.; Silver, P.J.

    1986-03-05

    Calmodulin (CaM) stimulates plasma membrane transport in many cell types, however, its role in Ca regulation by the sarcoplasmic reticulum (SR) in smooth muscle has not been established. /sup 45/Ca uptake was studied in saponin skinned strips of rat caudal artery as a function of CaM and the CaM inhibitors, W-7, calmidazolium (CaMZ), and trifluoperazine (TFP). Although caudal artery strips lose approximately 30% of total tissue CaM during skinning, 0.3 - 2 ..mu..M CaM did not increase /sup 45/Ca uptake over a wide range of free Ca concentrations (10/sup -8/ - 10/sup -6/M). Neither W-7 nor CaMZ at concentration of 10/sup -4/ - 2 x 10/sup -4/M inhibited the MgATP-dependent Ca uptake. Ca uptake was not affected by 50 ..mu..M TFP but a significant inhibition was produced by 500 ..mu..M. Studies of the effects of TFP on /sup 45/Ca efflux indicated that TFP concentrations which inhibited Ca uptake also significantly increased the rate of Ca release. The results suggest that total Ca uptake in caudal artery depends mainly upon MgATP and is not modulated by exogenous CaM or affected by these CaM inhibitors. They cannot preclude that CaM may affect initial velocities or that the CaM inhibitors failed to reach active sites.

  8. Elevated Uptake of Plasma Macromolecules by Regions of Arterial Wall Predisposed to Plaque Instability in a Mouse Model

    PubMed Central

    Mohri, Zahra; Rowland, Ethan M.; Clarke, Lindsey A.; De Luca, Amalia; Peiffer, Véronique; Krams, Rob; Sherwin, Spencer J.; Weinberg, Peter D.

    2014-01-01

    Atherosclerosis may be triggered by an elevated net transport of lipid-carrying macromolecules from plasma into the arterial wall. We hypothesised that whether lesions are of the thin-cap fibroatheroma (TCFA) type or are less fatty and more fibrous depends on the degree of elevation of transport, with greater uptake leading to the former. We further hypothesised that the degree of elevation can depend on haemodynamic wall shear stress characteristics and nitric oxide synthesis. Placing a tapered cuff around the carotid artery of apolipoprotein E -/- mice modifies patterns of shear stress and eNOS expression, and triggers lesion development at the upstream and downstream cuff margins; upstream but not downstream lesions resemble the TCFA. We measured wall uptake of a macromolecular tracer in the carotid artery of C57bl/6 mice after cuff placement. Uptake was elevated in the regions that develop lesions in hyperlipidaemic mice and was significantly more elevated where plaques of the TCFA type develop. Computational simulations and effects of reversing the cuff orientation indicated a role for solid as well as fluid mechanical stresses. Inhibiting NO synthesis abolished the difference in uptake between the upstream and downstream sites. The data support the hypothesis that excessively elevated wall uptake of plasma macromolecules initiates the development of the TCFA, suggest that such uptake can result from solid and fluid mechanical stresses, and are consistent with a role for NO synthesis. Modification of wall transport properties might form the basis of novel methods for reducing plaque rupture. PMID:25531765

  9. A primary fish gill cell culture model to assess pharmaceutical uptake and efflux: evidence for passive and facilitated transport.

    PubMed

    Stott, Lucy C; Schnell, Sabine; Hogstrand, Christer; Owen, Stewart F; Bury, Nic R

    2015-02-01

    The gill is the principle site of xenobiotic transfer to and from the aqueous environment. To replace, refine or reduce (3Rs) the large numbers of fish used in in vivo uptake studies an effective in vitro screen is required that mimics the function of the teleost gill. This study uses a rainbow trout (Oncorhynchus mykiss) primary gill cell culture system grown on permeable inserts, which tolerates apical freshwater thus mimicking the intact organ, to assess the uptake and efflux of pharmaceuticals across the gill. Bidirectional transport studies in media of seven pharmaceuticals (propranolol, metoprolol, atenolol, formoterol, terbutaline, ranitidine and imipramine) showed they were transported transcellularly across the epithelium. However, studies conducted in water showed enhanced uptake of propranolol, ranitidine and imipramine. Concentration-equilibrated conditions without a concentration gradient suggested that a proportion of the uptake of propranolol and imipramine is via a carrier-mediated process. Further study using propranolol showed that its transport is pH-dependent and at very low environmentally relevant concentrations (ng L(-1)), transport deviated from linearity. At higher concentrations, passive uptake dominated. Known inhibitors of drug transport proteins; cimetidine, MK571, cyclosporine A and quinidine inhibited propranolol uptake, whilst amantadine and verapamil were without effect. Together this suggests the involvement of specific members of SLC and ABC drug transporter families in pharmaceutical transport.

  10. Calcium-calmodulin-dependent kinase II (CaMKII) mediates insulin-stimulated proliferation and glucose uptake.

    PubMed

    Illario, Maddalena; Monaco, Sara; Cavallo, Anna Lina; Esposito, Iolanda; Formisano, Pietro; D'Andrea, Luca; Cipolletta, Ersilia; Trimarco, Bruno; Fenzi, Gianfranco; Rossi, Guido; Vitale, Mario

    2009-05-01

    Cellular growth and glucose uptake are regulated by multiple signals generated by the insulin receptor. The mechanisms of individual modulation of these signals remain somewhat elusive. We investigated the role of CaMKII in insulin signalling in a rat skeletal muscle cell line, demonstrating that CaMKII modulates the insulin action on DNA synthesis and the negative feedback that down regulates glucose uptake. Insulin stimulation generated partly independent signals leading to the rapid activation of Akt, Erk-1/2 and CaMKII. Akt activation was followed by Glut-4 translocation to the plasma membrane and increase of glucose uptake. Then, IRS-1 was phosphorylated at S612, the IRS-1/p85PI3K complex was disrupted, Akt was no more phosphorylated and both Glut-4 translocation and glucose uptake were reduced. Inhibition of CaMKII abrogated the insulin-induced Erk-1/2 activation, DNA synthesis and phosphorylation of IRS-1 at S612. Inhibition of CaMKII also abrogated the down-regulation of insulin-stimulated Akt phosphorylation, Glut-4 membrane translocation and glucose uptake. These results demonstrate that: 1 - CaMKII modulates the insulin-induced Erk-1/2 activation and cell proliferation; 2 - after the initial stimulation of the IRS-1/Akt pathway, CaMKII mediates the down-regulation of stimulated glucose uptake. This represents a novel mechanism in the selective control of insulin signals, and a possible site for pharmacological intervention.

  11. Influence of soil structure on unsaturated water flow including root uptake

    NASA Astrophysics Data System (ADS)

    Kuhlmann, Anna; Neuweiler, Insa; van der Zee, Sjoerd; Helmig, Rainer

    2010-05-01

    The development of effective irrigation strategies is of great importance as the scarcity of water during extended dry periods in aride areas leads to limited water uptake by roots and thus to restricted growth and eventually to wilting of plants. To approach this goal a broad understanding of the factors which influence the distribution of the water potential and the interactions with root uptake is crucial. Soil structure is supposed to have a large impact on water flow especially under dry conditions when the variability of soil parameters is increased. For field applications, predictions of the water flow are needed for large scales where the scarcity of measurements leads to a high level of uncertainty about the detailed distribution of soil parameters. Thus stochastic methods in which heterogeneity of soil is described by a random parameter field are used. In this presentation, the interrelation of root uptake and heterogeneity is analyzed using numerical simulations. Random parameter fields with Gaussian and non-Gaussian dependence were parameterized according to the Las Cruces Trench Site dataset and used as input for the numerical model. Transpiration is considered in a macroscopic way as a sink term with a prescribed potential extraction rate at each node, determined by the density distribution of the plants and with restricted uptake due to unfavorable conditions as lack of water and oxygen (modeled according to the Feddes - Function). With this basic model, water flow in two dimensional random fields has been investigated under dry conditions. It was observed that dry spots - regions in which roots dry up to the wilting point form when the structure shows isolated high extreme values in conductivity. In these dry regions, roots take up a decreased amount of water such that the total potential demand is not met anymore. This seems rather unrealistic as sufficient water is available at other locations of the domain. Thus two other approaches are analyzed

  12. First respiration estimates of cold-seep vesicomyid bivalves from in situ total oxygen uptake measurements.

    PubMed

    Decker, Carole; Caprais, Jean-Claude; Khripounoff, Alexis; Olu, Karine

    2012-04-01

    Vesicomyid bivalves are one of the most abundant symbiont-bearing species inhabiting deep-sea reducing ecosystems. Nevertheless, except for the hydrothermal vent clam Calyptogena magnifica, their metabolic rates have not been documented, and only assessed with ex situ experiments. In this study, gathering benthic chamber measurements and biomass estimation, we give the first in situ assessment of the respiration rate of these bivalves. The giant pockmark Regab, located at 3160m depth along the Congo-Angola margin, is a cold-seep site characterised by dense assemblages of two species of vesicomyids: Christineconcha regab and Laubiericoncha chuni with high dominance of C. regab. Two sites with dense aggregates of vesicomyids were selected to measure total oxygen uptake (TOU), and methane fluxes using IFREMER's benthic chamber CALMAR deployed by the ROV Quest 4000 (MARUM). Photographs were taken and bivalves were sampled using blade corers to estimate density and biomass. Total oxygen uptake was higher at Site 2 compared to Site 1 (respectively 492 mmol.m(-2).d(-1) and 332 mmol.m(-2).d(-1)). However, given vesicomyid densities and biomass, mean oxygen consumption rates were similar at both sites (1.9 to 2.5 μmol.g total dry mass(-1).h(-1) at the Site 1 and 1.8 to 2.3 μmol.g total dry mass(-1).h(-1) at Site 2). These respiration rates are higher than published ex situ estimates for cold-seep or hydrothermal vent bivalves. Although methane fluxes at the base of sulphide production were clearly higher at Site 2 (14.6 mmol.m(-2).d(-1)) than at Site 1 (0.3 mmol.m(-2).d(-1)), they do not seem to influence the respiration rates of these bivalves associated to sulphide-oxidizing symbionts. PMID:22578572

  13. First respiration estimates of cold-seep vesicomyid bivalves from in situ total oxygen uptake measurements.

    PubMed

    Decker, Carole; Caprais, Jean-Claude; Khripounoff, Alexis; Olu, Karine

    2012-04-01

    Vesicomyid bivalves are one of the most abundant symbiont-bearing species inhabiting deep-sea reducing ecosystems. Nevertheless, except for the hydrothermal vent clam Calyptogena magnifica, their metabolic rates have not been documented, and only assessed with ex situ experiments. In this study, gathering benthic chamber measurements and biomass estimation, we give the first in situ assessment of the respiration rate of these bivalves. The giant pockmark Regab, located at 3160m depth along the Congo-Angola margin, is a cold-seep site characterised by dense assemblages of two species of vesicomyids: Christineconcha regab and Laubiericoncha chuni with high dominance of C. regab. Two sites with dense aggregates of vesicomyids were selected to measure total oxygen uptake (TOU), and methane fluxes using IFREMER's benthic chamber CALMAR deployed by the ROV Quest 4000 (MARUM). Photographs were taken and bivalves were sampled using blade corers to estimate density and biomass. Total oxygen uptake was higher at Site 2 compared to Site 1 (respectively 492 mmol.m(-2).d(-1) and 332 mmol.m(-2).d(-1)). However, given vesicomyid densities and biomass, mean oxygen consumption rates were similar at both sites (1.9 to 2.5 μmol.g total dry mass(-1).h(-1) at the Site 1 and 1.8 to 2.3 μmol.g total dry mass(-1).h(-1) at Site 2). These respiration rates are higher than published ex situ estimates for cold-seep or hydrothermal vent bivalves. Although methane fluxes at the base of sulphide production were clearly higher at Site 2 (14.6 mmol.m(-2).d(-1)) than at Site 1 (0.3 mmol.m(-2).d(-1)), they do not seem to influence the respiration rates of these bivalves associated to sulphide-oxidizing symbionts.

  14. Characterization of cadmium uptake in Lactobacillus plantarum and isolation of cadmium and manganese uptake mutants

    SciTech Connect

    Hao, Z.; Reiske, H.R.; Wilson, D.B.

    1999-11-01

    Two different Cd{sup 2+} uptake systems were identified in Lactobacillus plantarum. One is a high-affinity, high-velocity Mn{sup 2+} uptake system which also takes up Cd{sup 2+} and is induced by Mn{sup 2+} starvation. The calculated K{sub m} and V{sub max} are 0.26 {mu}M and 3.6 {mu}mol g of dry cell{sup {minus}1} min{sup {minus}1}, respectively. Unlike Mn{sup 2+} uptake, which is facilitated by citrate and related tricarboxylic acids, Cd{sup 2+} uptake is weakly inhibited by citrate. Cd{sup 2+} and Mn{sup 2+} are competitive inhibitors of each other, and the affinity of the system for Cd{sup 2+} is higher than that for Mn{sup 2+}. The other Cd{sup 2+} uptake system is expressed in Mn{sup 2+}-sufficient cells, and no K{sub m} can be calculated for it because uptake is nonsaturable. Mn{sup 2+} does not compete for transport through this system, nor does any other tested cation, i.e., Zn{sup 2+}, Cu{sup 2+}, Co{sup 2+}, Mg{sup 2+}, Ca{sup 2+}, Fe{sup 2+}, or Ni{sup 2+}. Both systems require energy, since uncouplers completely inhibit their activities. Two Mn{sup 2+}-dependent L. plantarum mutants were isolated by chemical mutagenesis and ampicillin enrichment. They required more than 5,000 times as much Mn{sup 2+} for growth as the parental strain. Mn{sup 2+} starvation-induced Cd{sup 2+} uptake in both mutants was less than 5% the wild-type rate. The low level of long-term Mn{sup 2+} or Cd{sup 2+} accumulation by the mutant strains also shows that the mutations eliminate the high-affinity Mn{sup 2+} and Cd{sup 2+} uptake system.

  15. Uptake of Mass Drug Administration Programme for Schistosomiasis Control in Koome Islands, Central Uganda

    PubMed Central

    Tuhebwe, Doreen; Bagonza, James; Kiracho, Elizabeth Ekirapa; Yeka, Adoke; Elliott, Alison M.; Nuwaha, Fred

    2015-01-01

    Introduction Schistosomiasis is one of the neglected tropical diseases targeted for elimination in Uganda through the Mass Drug Administration (MDA) programme. Praziquantel has been distributed using community resource persons in fixed sites and house-to-house visits; however the uptake is still below target coverage. In 2011/2012 MDA exercise, uptake stood at 50% yet WHO target coverage is 75% at community level. We assessed the uptake of MDA and the associated factors in Koome Islands, Central Uganda. Methods In March 2013, we conducted a mixed methods cross sectional study in 15 randomly selected villages. We interviewed a total of 615 respondents aged 18 years and above using semi structured questionnaires and five key informants were also purposively selected. Univariate and multivariate analysis was done. MDA uptake was defined as self reported swallowing of praziquantel during the last (2012) MDA campaign. We conducted key informant interviews with Ministry of Health, district health personnel and community health workers. Results Self reported uptake of praziquantel was 44.7% (275/615), 95% confidence interval (CI) 40.8–48.7%. Of the 275 community members who said they had swallowed praziquantel, 142 (51.6%) reported that they had developed side effects. Uptake of MDA was more likely if the respondent was knowledgeable about schistosomiasis transmission and prevention (adjusted odds ratio [AOR] 1.85, 95% CI 1.22–2.81) and reported to have received health education from the health personnel (AOR 5.95, 95% CI 3.67–9.65). Service delivery challenges such as drug shortages and community health worker attrition also influenced MDA in Koome Islands. Conclusions Uptake of MDA for schistosomiasis control in Koome was sub optimal. Lack of knowledge about schistosomiasis transmission and prevention, inadequate health education and drug shortages are some of the major factors associated with low uptake. These could be addressed through routine health education

  16. Modeling the uptake and transpiration of TCE using phreatophytic trees. Master`s Thesis

    SciTech Connect

    Wise, D.P.

    1997-12-01

    Phytoremediation is a recent addition to the numerous methods used today to remediate ground water contaminants. It is proving more effective and efficient compared to existing remediation techniques. The use of phreatophytes, or water seeking trees, has great potential for phytoremediation. These trees are fast growing, long lived, grow their roots down to the ground water table, transpire large amounts of water, and are proven to actively remove contaminants from the soil horizon. The purpose of this research is to develop quantitative concepts for understanding the dynamics of TCE uptake and transpiration by phreatophytic trees over a short rotation woody crop time frame. This will he done by constructing a system dynamics model of this process and running it over a wide range of conditions. This research will offer managers a tool to simulate long-term uptake and transpiration of TCE at potential sites. The results of this study indicate that TCE is actively removed from the soil horizon by phreatophytic trees and a significant proportion of this TCE is then transpired. Changes in soil horizon parameters, xylem flow rates, and variables in the uptake equation greatly influence TCE uptake rates as well as transpiration. Also, parameters used in equations representing flows in and out of the leaf greatly influence transpiration. Better understanding of these processes is essential for managers to accurately predict the amount of TCE removed and transpired during potential phytoremediation projects.

  17. Selective MPP+ uptake into synaptic dopamine vesicles: possible involvement in MPTP neurotoxicity.

    PubMed Central

    Del Zompo, M.; Piccardi, M. P.; Ruiu, S.; Quartu, M.; Gessa, G. L.; Vaccari, A.

    1993-01-01

    1. In the present study we provide evidence for a saturable, Mg2+/ATP- and temperature-dependent, tetrabenazine-, dopamine-, and amphetamine-sensitive uptake of 1-methyl-4-phenylpyridinium ion (MPP+) in synaptic vesicles from mouse striatum. 2. Similarity in the properties of the vesicular uptake suggests that in the striatum dopamine and MPP+ share the vesicular carrier. 3. The presence of MPP+ vesicular uptake in dopamine-rich regions such as striatum, olfactory, tubercles and hypothalamus, as well as its absence in cerebellum, cortex and pons-medulla, suggest that monoamine vesicular carriers differ between highly and poorly dopamine-innervated regions. 4. The restriction of active MPP+ uptake to the dopaminergic regions, which reflects the previously shown distribution of [3H]-MPP+ binding sites in mouse brain membranes, indicates MPP+ as a marker of the vesicular carrier for dopamine in dopaminergic neurones. 5. A role in MPP+ neurotoxicity is suggested for this region-specific, vesicular storage of the toxin. Images Figure 1 PMID:8102929

  18. Bile acid inhibition of taurocholate uptake by rat hepatocytes: role of OH groups

    SciTech Connect

    Bellentani, S.; Hardison, W.G.M.; Marchegiano, P.; Zanasi, G.; Manenti, F.

    1987-03-01

    To define further the structural specificity of the taurocholate uptake site, the authors studied the ability of a variety of taurine-conjugated bile acids with differing hydroxyl substituents on the sterol moiety to inhibit (/sup 14/C) taurocholate uptake. Rat hepatocytes isolated by collagenase perfusion were incubated in a tris (hydroxymethyl) aminomethane-phosphate buffer containing (/sup 14/C)taurocholate in the presence or absence of inhibitor bile acid. Stronger inhibitors were studied at a fixed concentration of 5 ..mu..M, weaker ones at 25 ..mu..M. Initial uptake velocity was measured. Uptake velocity could then be related to taurocholate concentration and a V/sub max/ and K/sub m/ could be determined by applying a nonlinear least squares fit to the data obtained with or without inhibitor. The kinetic parameters allowed the determination of the type of inhibition and of inhibition constants (K/sub i/) of the various test bile acids. The data indicate that bile acids containing a 6- or 7-OH group exhibit competitive inhibition, whereas bile acids with no 6- or 7-OH group exhibit noncompetitive inhibition. Of the compounds exhibiting competitive inhibition, K/sub i/ varied with the number of hydroxyl groups on the sterol moiety. They conclude that the presence of absence of a 6- or 7-OH group dictates the mechanism of inhibition; the number of hydroxyl substituents determines the potency of competitive inhibition.

  19. Coastal-ocean uptake of anthropogenic carbon

    NASA Astrophysics Data System (ADS)

    Bourgeois, Timothée; Orr, James C.; Resplandy, Laure; Terhaar, Jens; Ethé, Christian; Gehlen, Marion; Bopp, Laurent

    2016-07-01

    Anthropogenic changes in atmosphere-ocean and atmosphere-land CO2 fluxes have been quantified extensively, but few studies have addressed the connection between land and ocean. In this transition zone, the coastal ocean, spatial and temporal data coverage is inadequate to assess its global budget. Thus we use a global ocean biogeochemical model to assess the coastal ocean's global inventory of anthropogenic CO2 and its spatial variability. We used an intermediate resolution, eddying version of the NEMO-PISCES model (ORCA05), varying from 20 to 50 km horizontally, i.e. coarse enough to allow multiple century-scale simulations but finer than coarse-resolution models (˜ 200 km) to better resolve coastal bathymetry and complex coastal currents. Here we define the coastal zone as the continental shelf area, excluding the proximal zone. Evaluation of the simulated air-sea fluxes of total CO2 for 45 coastal regions gave a correlation coefficient R of 0.8 when compared to observation-based estimates. Simulated global uptake of anthropogenic carbon results averaged 2.3 Pg C yr-1 during the years 1993-2012, consistent with previous estimates. Yet only 0.1 Pg C yr-1 of that is absorbed by the global coastal ocean. That represents 4.5 % of the anthropogenic carbon uptake of the global ocean, less than the 7.5 % proportion of coastal-to-global-ocean surface areas. Coastal uptake is weakened due to a bottleneck in offshore transport, which is inadequate to reduce the mean anthropogenic carbon concentration of coastal waters to the mean level found in the open-ocean mixed layer.

  20. Sugar uptake by intestinal basolateral membrane vesicles.

    PubMed

    Wright, E M; van Os, C H; Mircheff, A K

    1980-03-27

    A high yield of membrane vesicles was prepared from the basolateral surface of rat intestinal cells using an N2 cavitation bomb and density gradient centrifugation. The membranes were enriched 10-fold and were free of significatn contamination by brush border membranes and mitochondria. The rate of D-E114C]glucose and L-E13H]glucose uptake into the vesicle was measured using a rapid filtration technique. D-Glucose equilibrated within the vesicles with a half-time 1/25th that for L-glucose. The stereospecific uptake exhibited saturation kinetics with a Km of approx. 44 mM and a V of approx. 110 nmol . mg-1 min-1 at 10 degrees C. The activation energy for the process was 14 kcal . mol-1 below 15 degrees C and it approached 3 kcal . mol-1 above 22 degrees C. Carrier-mediated uptake was eliminated in the presence of 1 mM HgCl2 and 0.5 mM phloretin. The rate of transport was unaffected by the absence or presence of sodium concentration gradients. Competition studies demonstrated that all sugars with the D-glucose pyranose ring chair conformation shared the transport system, and that, with the possible exception of the -OH group at carbon No. 1, there were no specific requirements for an equatorial -OH group at any position in the pyranose ring. In the case of alpha-methyl-D-glucoside its inability to share the D-glucose transport system may be due to steric hindrance posed by the -OCH3 group rather than by a specific requirement for a free hydroxyl group at the position in the ring. It is concluded that sugars are transported across the basolateral membrane of the intestinal epithelium by a facilitated diffusion system reminiscent of that in human red blood cells. PMID:6245688

  1. Sugar uptake by intestinal basolateral membrane vesicles.

    PubMed

    Wright, E M; van Os, C H; Mircheff, A K

    1980-03-27

    A high yield of membrane vesicles was prepared from the basolateral surface of rat intestinal cells using an N2 cavitation bomb and density gradient centrifugation. The membranes were enriched 10-fold and were free of significatn contamination by brush border membranes and mitochondria. The rate of D-E114C]glucose and L-E13H]glucose uptake into the vesicle was measured using a rapid filtration technique. D-Glucose equilibrated within the vesicles with a half-time 1/25th that for L-glucose. The stereospecific uptake exhibited saturation kinetics with a Km of approx. 44 mM and a V of approx. 110 nmol . mg-1 min-1 at 10 degrees C. The activation energy for the process was 14 kcal . mol-1 below 15 degrees C and it approached 3 kcal . mol-1 above 22 degrees C. Carrier-mediated uptake was eliminated in the presence of 1 mM HgCl2 and 0.5 mM phloretin. The rate of transport was unaffected by the absence or presence of sodium concentration gradients. Competition studies demonstrated that all sugars with the D-glucose pyranose ring chair conformation shared the transport system, and that, with the possible exception of the -OH group at carbon No. 1, there were no specific requirements for an equatorial -OH group at any position in the pyranose ring. In the case of alpha-methyl-D-glucoside its inability to share the D-glucose transport system may be due to steric hindrance posed by the -OCH3 group rather than by a specific requirement for a free hydroxyl group at the position in the ring. It is concluded that sugars are transported across the basolateral membrane of the intestinal epithelium by a facilitated diffusion system reminiscent of that in human red blood cells.

  2. Angiotensin II reduces calcium uptake into bone.

    PubMed

    Schurman, Scott J; Bergstrom, William H; Shoemaker, Lawrence R; Welch, Thomas R

    2004-01-01

    Children with neonatal Bartter syndrome (NBS) have hypercalciuria, nephrocalcinosis, and osteopenia. A complex of basic-fibroblast growth factor (b-FGF) and a naturally occurring glycosaminoglycan has been identified in the serum and urine of NBS patients. This complex increases bone resorption in a bone disc bioassay system. Angiotensin II (AT II), which is increased in Bartter syndrome, increases the synthesis of b-FGF by cultured endothelial cells. Addition of 10(-8) M AT II to the bioassay, a concentration reported in Bartter syndrome patients, significantly decreased calcium uptake into bone discs [E/C 0.60 (0.04), P < 0.001 compared with buffer, normal E/C >0.90]. Adding b-FGF monoclonal antibody at 10 microg/ml [E/C 0.90 (0.06), P=NS] or indomethacin [E/C 1.00 (0.03), P=NS] to 10(-8 )M AT II neutralized this effect. In separate experiments, newborn rats were given intraperitoneal injections of AT II. Bone discs from these animals were used in the bioassay system and calcium uptake was markedly reduced compared with discs from rats injected with phosphate-buffered saline [AT II 6.6 x 10(-9), E/C 0.10 (0.04), P<0.001, AT II 3.3 x 10(-8), E/C 0.10 (0.05), P<0.001]. AT II decreases calcium uptake in the bone disc bioassay system. This effect can be abrogated by antibody to b-FGF or prostaglandin synthetase inhibition. These results support the hypothesis that in children with NBS, elevated levels of AT II stimulate local skeletal b-FGF synthesis, with a resultant increase in bone resorption via a prostaglandin-dependent pathway. PMID:14648327

  3. A Comparative Study of Iron Uptake Rates and Mechanisms amongst Marine and Fresh Water Cyanobacteria: Prevalence of Reductive Iron Uptake

    PubMed Central

    Lis, Hagar; Kranzler, Chana; Keren, Nir; Shaked, Yeala

    2015-01-01

    In this contribution, we address the question of iron bioavailability to cyanobacteria by measuring Fe uptake rates and probing for a reductive uptake pathway in diverse cyanobacterial species. We examined three Fe-substrates: dissolved inorganic iron (Fe') and the Fe-siderophores Ferrioxamine B (FOB) and FeAerobactin (FeAB). In order to compare across substrates and strains, we extracted uptake rate constants (kin = uptake rate/[Fe-substrate]). Fe' was the most bioavailable Fe form to cyanobacteria, with kin values higher than those of other substrates. When accounting for surface area (SA), all strains acquired Fe' at similar rates, as their kin/SA were similar. We also observed homogeneity in the uptake of FOB among strains, but with 10,000 times lower kin/SA values than Fe'. Uniformity in kin/SA suggests similarity in the mechanism of uptake and indeed, all strains were found to employ a reductive step in the uptake of Fe' and FOB. In contrast, different uptake pathways were found for FeAB along with variations in kin/SA. Our data supports the existence of a common reductive Fe uptake pathway amongst cyanobacteria, functioning alone or in addition to siderophore-mediated uptake. Cyanobacteria combining both uptake strategies benefit from increased flexibility in accessing different Fe-substrates. PMID:25768677

  4. Political and economic factors influencing contraceptive uptake.

    PubMed

    Sai, F T

    1993-01-01

    International, national and local level politics influence the uptake of contraception through consensuses, laws, financial and moral support or the creation of an enabling atmosphere. Opposition to contraception generally comes from some churches and groups opposed to particular technologies. Socio-economic factors, particularly education, the health care system and the perceived or actual cost of fertility regulation as compared to benefits expected from children also powerfully influence contraceptive use. For many poor women in developing countries their powerlessness in relation to their male partners is an important obstacle.

  5. Antigen Uptake during Different Life Stages of Zebrafish (Danio rerio) Using a GFP-Tagged Yersinia ruckeri.

    PubMed

    Korbut, Rozalia; Mehrdana, Foojan; Kania, Per Walter; Larsen, Marianne Halberg; Frees, Dorte; Dalsgaard, Inger; Jørgensen, Louise von Gersdorff

    2016-01-01

    Immersion-vaccines (bacterins) are routinely used for aquacultured rainbow trout to protect against Yersinia ruckeri (Yr). During immersion vaccination, rainbow trout take up and process the antigens, which induce protection. The zebrafish was used as a model organism to study uptake mechanisms and subsequent antigen transport in fish. A genetically modified Yr was developed to constitutively express green fluorescent protein (GFP) and was used for bacterin production. Larval, juvenile and adult transparent zebrafish (tra:nac mutant) received a bath in the bacterin for up to 30 minutes. Samples were taken after 1 min, 15 min, 30 min, 2 h, 12 h and 24 h. At each sampling point fish were used for live imaging of the uptake using a fluorescence stereomicroscope and for immunohistochemistry (IHC). In adult fish, the bacterin could be traced within 30 min in scale pockets, skin, oesophagus, intestine and fins. Within two hours post bath (pb) Yr-antigens were visible in the spleen and at 24 h in liver and kidney. Bacteria were associated with the gills, but uptake at this location was limited. Antigens were rarely detected in the blood and never in the nares. In juvenile fish uptake of the bacterin was seen in the intestine 30 min pb and in the nares 2 hpb but never in scale pockets. Antigens were detected in the spleen 12 hpb. Zebrafish larvae exhibited major Yr uptake only in the mid-intestine enterocytes 24 hpb. The different life stages of zebrafish varied with regard to uptake locations, however the gut was consistently a major uptake site. Zebrafish and rainbow trout tend to have similar uptake mechanisms following immersion or bath vaccination, which points towards zebrafish as a suitable model organism for this aquacultured species. PMID:27404564

  6. Antigen Uptake during Different Life Stages of Zebrafish (Danio rerio) Using a GFP-Tagged Yersinia ruckeri

    PubMed Central

    Korbut, Rozalia; Mehrdana, Foojan; Kania, Per Walter; Larsen, Marianne Halberg; Frees, Dorte; Dalsgaard, Inger; Jørgensen, Louise von Gersdorff

    2016-01-01

    Immersion-vaccines (bacterins) are routinely used for aquacultured rainbow trout to protect against Yersinia ruckeri (Yr). During immersion vaccination, rainbow trout take up and process the antigens, which induce protection. The zebrafish was used as a model organism to study uptake mechanisms and subsequent antigen transport in fish. A genetically modified Yr was developed to constitutively express green fluorescent protein (GFP) and was used for bacterin production. Larval, juvenile and adult transparent zebrafish (tra:nac mutant) received a bath in the bacterin for up to 30 minutes. Samples were taken after 1 min, 15 min, 30 min, 2 h, 12 h and 24 h. At each sampling point fish were used for live imaging of the uptake using a fluorescence stereomicroscope and for immunohistochemistry (IHC). In adult fish, the bacterin could be traced within 30 min in scale pockets, skin, oesophagus, intestine and fins. Within two hours post bath (pb) Yr-antigens were visible in the spleen and at 24 h in liver and kidney. Bacteria were associated with the gills, but uptake at this location was limited. Antigens were rarely detected in the blood and never in the nares. In juvenile fish uptake of the bacterin was seen in the intestine 30 min pb and in the nares 2 hpb but never in scale pockets. Antigens were detected in the spleen 12 hpb. Zebrafish larvae exhibited major Yr uptake only in the mid-intestine enterocytes 24 hpb. The different life stages of zebrafish varied with regard to uptake locations, however the gut was consistently a major uptake site. Zebrafish and rainbow trout tend to have similar uptake mechanisms following immersion or bath vaccination, which points towards zebrafish as a suitable model organism for this aquacultured species. PMID:27404564

  7. Antigen Uptake during Different Life Stages of Zebrafish (Danio rerio) Using a GFP-Tagged Yersinia ruckeri.

    PubMed

    Korbut, Rozalia; Mehrdana, Foojan; Kania, Per Walter; Larsen, Marianne Halberg; Frees, Dorte; Dalsgaard, Inger; Jørgensen, Louise von Gersdorff

    2016-01-01

    Immersion-vaccines (bacterins) are routinely used for aquacultured rainbow trout to protect against Yersinia ruckeri (Yr). During immersion vaccination, rainbow trout take up and process the antigens, which induce protection. The zebrafish was used as a model organism to study uptake mechanisms and subsequent antigen transport in fish. A genetically modified Yr was developed to constitutively express green fluorescent protein (GFP) and was used for bacterin production. Larval, juvenile and adult transparent zebrafish (tra:nac mutant) received a bath in the bacterin for up to 30 minutes. Samples were taken after 1 min, 15 min, 30 min, 2 h, 12 h and 24 h. At each sampling point fish were used for live imaging of the uptake using a fluorescence stereomicroscope and for immunohistochemistry (IHC). In adult fish, the bacterin could be traced within 30 min in scale pockets, skin, oesophagus, intestine and fins. Within two hours post bath (pb) Yr-antigens were visible in the spleen and at 24 h in liver and kidney. Bacteria were associated with the gills, but uptake at this location was limited. Antigens were rarely detected in the blood and never in the nares. In juvenile fish uptake of the bacterin was seen in the intestine 30 min pb and in the nares 2 hpb but never in scale pockets. Antigens were detected in the spleen 12 hpb. Zebrafish larvae exhibited major Yr uptake only in the mid-intestine enterocytes 24 hpb. The different life stages of zebrafish varied with regard to uptake locations, however the gut was consistently a major uptake site. Zebrafish and rainbow trout tend to have similar uptake mechanisms following immersion or bath vaccination, which points towards zebrafish as a suitable model organism for this aquacultured species.

  8. Positive newborn screen for methylmalonic aciduria identifies the first mutation in TCblR/CD320, the gene for cellular uptake of transcobalamin-bound vitamin B(12).

    PubMed

    Quadros, Edward V; Lai, Shao-Chiang; Nakayama, Yasumi; Sequeira, Jeffrey M; Hannibal, Luciana; Wang, Sihe; Jacobsen, Donald W; Fedosov, Sergey; Wright, Erica; Gallagher, Renata C; Anastasio, Natascia; Watkins, David; Rosenblatt, David S

    2010-08-01

    Elevated methylmalonic acid in five asymptomatic newborns whose fibroblasts showed decreased uptake of transcobalamin-bound cobalamin (holo-TC), suggested a defect in the cellular uptake of cobalamin. Analysis of TCblR/CD320, the gene for the receptor for cellular uptake of holo-TC, identified a homozygous single codon deletion, c.262_264GAG (p.E88del), resulting in the loss of a glutamic acid residue in the low-density lipoprotein receptor type A-like domain. Inserting the codon by site-directed mutagenesis fully restored TCblR function.

  9. Requirement of glycogenolysis for uptake of increased extracellular K+ in astrocytes: potential implications for K+ homeostasis and glycogen usage in brain.

    PubMed

    Xu, Junnan; Song, Dan; Xue, Zhanxia; Gu, Li; Hertz, Leif; Peng, Liang

    2013-03-01

    The importance of astrocytic K(+) uptake for extracellular K(+) ([K(+)](e)) clearance during neuronal stimulation or pathophysiological conditions is increasingly acknowledged. It occurs by preferential stimulation of the astrocytic Na(+),K(+)-ATPase, which has higher K(m) and V(max) values than its neuronal counterpart, at more highly increased [K(+)](e) with additional support of the cotransporter NKCC1. Triggered by a recent DiNuzzo et al. paper, we used administration of the glycogenolysis inhibitor DAB to primary cultures of mouse astrocytes to determine whether K(+) uptake required K(+)-stimulated glycogenolysis. KCl was increased by either 5 mM (stimulating only the Na(+),K(+)-ATPase) or 10 mM (stimulating both transporters) in glucose-containing saline media prepared to become iso-osmotic after the addition. DAB completely inhibited both uptakes, the Na(+),K(+)-ATPase-mediated by preventing Na(+) uptake for stimulation of its intracellular Na(+)-activated site, and the NKCC1-mediated uptake by inhibition of depolarization- and L-channel-mediated Ca(2+) uptake. Drugs inhibiting the signaling pathways involved in either of these processes also abolished K(+) uptake. Assuming similar in vivo characteristics, partly supported by literature data, K(+)-stimulated astrocytic K(+) uptake must discontinue after normalization of extracellular K(+). This will allow Kir1.4-mediated release and reuptake by the less powerful neuronal Na(+),K(+)-ATPase.

  10. Site Construction.

    ERIC Educational Resources Information Center

    Richardson, Eric C.

    1996-01-01

    Presents a guide to planning and building a Web site, with an emphasis on setting up a Web server. Discussion includes hiring a consultant, contracts and payment, assembly of teams, training, development of a business plan, registration of domain name, purchase of hardware and software, local area networks, and types of Internet connection. (JKP)

  11. d-Galactose Uptake by Fenugreek Cotyledons 1

    PubMed Central

    Zambou, Katerina; Spyropoulos, Caroline G.

    1990-01-01

    The uptake of d-galactose was studied in detached fenugreek (Trigonella foenum-graecum L.) cotyledons. Uptake kinetics and treatment with p-chloromercury-benzenesulfonic acid indicated that at low concentrations d-galactose was taken up by a carrier. At higher concentrations a diffusion-like component existed. Proton flux and pH studies, treatment with α-naphthaleneacetic acid, and uptake experiments under water stress conditions suggested that d-galactose was not taken up via H+ contransport. However, d-galactose uptake was under metabolic control. Uptake kinetics under water stress conditions suggested that moderate water stress either increased the Km of the carrier or decreased the Vmax. However, prolonged stress transformed the carrier-mediated uptake into a diffusion uptake transport. The uptake of d-galactose by fenugreek cotyledons was very low before and just after germination, was maximum after 35 hours imbibition, and started decreasing thereafter. The different uptake rates of d-galactose with imbibition times were attributed to the operation of the carrier. At low uptake rates the carrier did not operate. Treatment with cycloheximide suggested that the carrier was synthesized de novo just after germination and stopped operating when all galactomannan hydrolysis was over. Results were discussed in the context of control of endosperm galactomannan hydrolysis by the cotyledons of fenugreek embryo. PMID:16667633

  12. Similarity in microbial amino acid uptake in surface waters of the North and South Atlantic (sub-)tropical gyres

    NASA Astrophysics Data System (ADS)

    Hill, Polly G.; Mary, Isabelle; Purdie, Duncan A.; Zubkov, Mikhail V.

    2011-12-01

    The Earth’s most extensive biomes - the oceanic subtropical gyres - are considered to be expanding with current surface ocean warming. Although it is well established that microbial communities control gyre biogeochemistry, comparisons of their metabolic activities between gyres are limited. In order to estimate metabolic activities including production of microbial communities, the uptake rates of amino acids leucine, methionine and tyrosine at ambient concentrations were estimated in surface waters of the Atlantic Ocean using radioisotopically labelled tracers. Data were acquired during six research cruises covering main oceanic provinces herein termed: North and South Atlantic Gyres, Bermuda Atlantic Time-series Study site (BATS), Equatorial region, and Mauritanian Upwelling (off Cape Blanc). Data were divided between provinces, the extents of which were identified by ocean colour data, in order to achieve provincial mean uptake rates. Leucine and methionine uptake rates did not differ between sampling periods, and were comparable between the North and South subtropical gyres. Furthermore, variation in uptake rates measured throughout the two oligotrophic gyres, where sampling covered ∼4 × 10 6 km 2, was considerably lower than that measured within the Mauritanian Upwelling and Equatorial regions, and even at the BATS site. Tyrosine was generally the slowest of the amino acids to be taken up, however, it was assimilated faster than methionine within the Mauritanian Upwelling region. Thus, we propose that one value for leucine (12.6 ± 3.2 pmol L -1 h -1) and methionine (10.0 ± 3.3 pmol L -1 h -1) uptake could be applied to the oligotrophic subtropical gyres of the Atlantic Ocean. However, with the significantly lower uptake rates observed at the BATS site, we would not advise extrapolation to the Sargasso Sea.

  13. Assessment of producers' response to Salmonella biosecurity issues and uptake of advice on laying hen farms in England and Wales.

    PubMed

    Gosling, R J; Martelli, F; Wintrip, A; Sayers, A R; Wheeler, K; Davies, R H

    2014-01-01

    High standards of biosecurity are known to reduce the risk of disease outbreaks; however, uptake of advice and implementation of biosecurity measures are dependent on many factors. This study assessed the uptake of targeted biosecurity advice by 60 laying hen farms provided during biosecurity audit visits. Advice was provided as bullet point cards focusing on specific areas identified as benefitting from improvement. These covered site entrance, site tidiness, vaccination, boot hygiene, hand hygiene, house tidiness, rodent control, fly control, red mite control and cleaning and disinfection between flocks. Background knowledge of Salmonella and biosecurity and farmers' willingness and intent to implement additional measures were assessed. About 50% of the principal decision-makers had basic background knowledge of Salmonella, with 22% considered well informed; almost all agreed that biosecurity could impact on Salmonella control and many appeared willing to implement additional biosecurity measures. Sixty-three per cent of study farms were categorised using the Defra Farmer Segmentation Model as Modern Family Businesses (MFBs), with 7-11% of farms being categorised as Custodian, Lifestyle Choice, Pragmatist or Challenged Enterprise; however, categorisation, did not determine uptake of advice. The most frequently used advice cards were boot hygiene, red mite control, hand hygiene, site entrance and cleaning and disinfection; uptake of advice ranged from 54 to 80% depending on the advice card. Uptake of advice by the farmers was encouraging, especially considering it was being provided by people other than their usual source of biosecurity information. Those who did not implement the recommended measures cited cost, difficulty of enforcement and practicality as the main reasons. However, the positive uptake of advice and implementation of recommended measures by many farmers demonstrates that targeted advice, discussed face to face with farmers, on a small number of

  14. Assessment of producers' response to Salmonella biosecurity issues and uptake of advice on laying hen farms in England and Wales.

    PubMed

    Gosling, R J; Martelli, F; Wintrip, A; Sayers, A R; Wheeler, K; Davies, R H

    2014-01-01

    High standards of biosecurity are known to reduce the risk of disease outbreaks; however, uptake of advice and implementation of biosecurity measures are dependent on many factors. This study assessed the uptake of targeted biosecurity advice by 60 laying hen farms provided during biosecurity audit visits. Advice was provided as bullet point cards focusing on specific areas identified as benefitting from improvement. These covered site entrance, site tidiness, vaccination, boot hygiene, hand hygiene, house tidiness, rodent control, fly control, red mite control and cleaning and disinfection between flocks. Background knowledge of Salmonella and biosecurity and farmers' willingness and intent to implement additional measures were assessed. About 50% of the principal decision-makers had basic background knowledge of Salmonella, with 22% considered well informed; almost all agreed that biosecurity could impact on Salmonella control and many appeared willing to implement additional biosecurity measures. Sixty-three per cent of study farms were categorised using the Defra Farmer Segmentation Model as Modern Family Businesses (MFBs), with 7-11% of farms being categorised as Custodian, Lifestyle Choice, Pragmatist or Challenged Enterprise; however, categorisation, did not determine uptake of advice. The most frequently used advice cards were boot hygiene, red mite control, hand hygiene, site entrance and cleaning and disinfection; uptake of advice ranged from 54 to 80% depending on the advice card. Uptake of advice by the farmers was encouraging, especially considering it was being provided by people other than their usual source of biosecurity information. Those who did not implement the recommended measures cited cost, difficulty of enforcement and practicality as the main reasons. However, the positive uptake of advice and implementation of recommended measures by many farmers demonstrates that targeted advice, discussed face to face with farmers, on a small number of

  15. Chemical hydrophobicity and uptake by plant roots.

    PubMed

    Dettenmaier, Erik M; Doucette, William J; Bugbee, Bruce

    2009-01-15

    The transpiration stream concentration factor (TSCF), the ratio between a compound's concentration in the xylem to that in the solution adjacent to the roots, is commonly used to describe the relative ability of an organic compound to be passively transported from root to shoot. Widely cited bell-shaped curves relating TSCFto the octanol/water partition coefficient (log Kow) imply that significant root uptake and transfer into shoot tissues occurs only for compounds falling within an intermediate hydrophobicity range. However, recent laboratory and field data for relatively water soluble compounds such as sulfolane, methyl tert-butyl ether (MTBE), and 1,4-dioxane suggest that these relationships are not universally applicable, especiallyfor nonionizable, highly polar, water soluble organics. To re-evaluate the relationship between root uptake and chemical hydrophobicity, TSCFs were measured for 25 organic chemicals ranging in log Kow from -0.8 to 5 using a pressure chamber technique. Using the TSCF values measured in this study, a new empirical relationship between TSCF (0 and 1) and log Kow (-0.8 to 5) is presented that indicates that nonionizable, polar, highly water soluble organic compounds are most likely to be taken up by plant roots and translocated to shoot tissue.

  16. Pharmacokinetics of sevoflurane uptake into the brain.

    PubMed

    Turner, M J; McCulloch, T J; Kennedy, R R; Baker, A B

    2004-12-01

    Two recent studies have examined the pharmacokinetics of sevoflurane in adults. Lu et al.(Pharmacokinetics of sevoflurane uptake into the brain and body, Anaesthesia 2003; 58: 951-6) observed that jugular bulb sevoflurane concentration initially rose unexpectedly rapidly and then approached arterial concentrations unexpectedly slowly, suggesting that a blood-brain diffusion barrier exists. They also observed a large alveolar-arterial sevoflurane gradient, suggesting that an alveolar-arterial diffusion barrier exists. Nakamura et al. (Predicted sevoflurane partial pressure in the brain with an uptake and distribution model: Comparison with the measured value in internal jugular vein blood. Journal of Clinical Monitoring and Computing 1999; 15: 299-305) found no diffusion barriers. We used a computer model to analyse both data sets and show that the observations of Lu et al. can be explained by contamination of jugular samples with extracerebral blood. It is possible that the alveolar-arterial gradients observed by Lu et al. are due to discrepancies in conversions between blood concentrations and gas partial pressures. Our study suggests that there is no blood-brain diffusion barrier for sevoflurane and that the data of Lu et al. must be interpreted with caution.

  17. Liver uptake of biguanides in rats.

    PubMed

    Sogame, Yoshihisa; Kitamura, Atsushi; Yabuki, Masashi; Komuro, Setsuko

    2011-09-01

    Metformin is an oral antihyperglycaemic agent widely used in the management of non-insulin-dependent diabetes mellitus. The liver is the primary target, metformin being taken up into human and rat hepatocytes via an active transport mechanism. The present study was designed to compare hepatic uptake of two biguanides, metformin and phenformin, in vitro and in vivo. In in vitro experiments, performed using rat cryopreserved hepatocytes, phenformin exhibited a much higher affinity and transport than metformin, with marked differences in kinetics. The K(m) values for metformin and phenformin were 404 and 5.17μM, respectively, with CLint (V(max)/K(m)) values 1.58μl/min per 10(6) cells and 34.7μl/min per 10(6) cells. In in vivo experiments, when (14)C-metformin and (14)C-phenformin were given orally to male rats at a dose of 50mg/kg, the liver concentrations of radioactivity at 0.5 hour after dosing were 21.5μg eq./g with metformin but 147.1μg eq./g for phenformin, ratios of liver to plasma concentrations being 4.2 and 61.3, respectively. In conclusion, the results suggest that uptake of biguanides by rat hepatocytes is in line with the liver distribution found in vivo, phenformin being more efficiently taken up by liver than metformin after oral administration.

  18. Freehand SPECT in low uptake situations

    NASA Astrophysics Data System (ADS)

    Lasser, Tobias; Ziegler, Sibylle I.; Navab, Nassir

    2011-03-01

    3D functional imaging in the operating room can be extremely useful for some procedures like SLN mapping or SLN biopsies. Freehand SPECT is an example of such an imaging modality, combining manually scanned, hand-held 1D gamma detectors with spatial positioning systems in order to reconstruct localized 3D SPECT images, for example in the breast or neck region. Standard series expansion methods are applied together with custom physical models of the acquisition process and custom filtering procedures to perform 3D tomographic reconstruction from sparse, limited-angle and irregularly sampled data. A Freehand SPECT system can easily be assembled on a mobile cart suitable for use in the operating room. This work addresses in particular the problem of objects with low uptake (like sentinel lymph nodes), where reconstruction tends to be difficult due to low signal to noise ratio. In a neck-like phantom study, we show that four simulated nodes of 250 microliter volume with 0.06% respectively 0.03% uptake of a virtual 70MBq injection of Tc99m (the typical activity for SLN procedures at our hospital) in a background of water can be reconstructed successfully using careful filtering procedures in the reconstruction pipeline. Ten independent Freehand SPECT scans of the phantom were performed by several different operators, with an average scan duration of 5.1 minutes. The resulting reconstructions show an average spatial accuracy within voxel dimensions (2.5mm) compared to CT and exhibit correct relative quantification.

  19. Imaging neurotransmitter uptake and depletion in astrocytes

    SciTech Connect

    Tan, W. |; Haydon, P.G.; Yeung, E.S.

    1997-08-01

    An ultraviolet (UV) laser-based optical microscope and charge-coupled device (CCD) detection system was used to obtain chemical images of biological cells. Subcellular structures can be easily seen in both optical and fluorescence images. Laser-induced native fluorescence detection provides high sensitivity and low limits of detection, and it does not require coupling to fluorescent dyes. We were able to quantitatively monitor serotonin that has been taken up into and released from individual astrocytes on the basis of its native fluorescence. Different regions of the cells took up different amounts of serotonin with a variety of uptake kinetics. Similarly, we observed different serotonin depletion dynamics in different astrocyte regions. There were also some astrocyte areas where no serotonin uptake or depletion was observed. Potential applications include the mapping of other biogenic species in cells as well as the ability to image their release from specific regions of cells in response to external stimuli. {copyright} {ital 1997} {ital Society for Applied Spectroscopy}

  20. Pathways of Arsenic Uptake and Efflux

    PubMed Central

    Yang, Hung-Chi; Fu, Hsueh-Liang; Lin, Yung-Feng; Rosen, Barry P.

    2015-01-01

    Arsenic is the most prevalent environmental toxic substance and ranks first on the U.S. Environmental Protection Agency’s Superfund List. Arsenic is a carcinogen and a causative agent of numerous human diseases. Paradoxically arsenic is used as a chemotherapeutic agent for treatment of acute promyelocytic leukemia. Inorganic arsenic has two biological important oxidation states: As(V) (arsenate) and As(III) (arsenite). Arsenic uptake is adventitious because the arsenate and arsenite are chemically similar to required nutrients. Arsenate resembles phosphate and is a competitive inhibitor of many phosphate-utilizing enzymes. Arsenate is taken up by phosphate transport systems. In contrast, at physiological pH, the form of arsenite is As(OH)3, which resembles organic molecules such as glycerol. Consequently, arsenite is taken into cells by aquaglyceroporin channels. Arsenic efflux systems are found in nearly every organism and evolved to rid cells of this toxic metalloid. These efflux systems include members of the multidrug resistance protein family and the bacterial exchangers Acr3 and ArsB. ArsB can also be a subunit of the ArsAB As(III)-translocating ATPase, an ATP-driven efflux pump. The ArsD metallochaperone binds cytosolic As(III) and transfers it to the ArsA subunit of the efflux pump. Knowledge of the pathways and transporters for arsenic uptake and efflux is essential for understanding its toxicity and carcinogenicity and for rational design of cancer chemotherapeutic drugs. PMID:23046656

  1. Mitochondrial calcium uptake capacity modulates neocortical excitability

    PubMed Central

    Sanganahalli, Basavaraju G; Herman, Peter; Hyder, Fahmeed; Kannurpatti, Sridhar S

    2013-01-01

    Local calcium (Ca2+) changes regulate central nervous system metabolism and communication integrated by subcellular processes including mitochondrial Ca2+ uptake. Mitochondria take up Ca2+ through the calcium uniporter (mCU) aided by cytoplasmic microdomains of high Ca2+. Known only in vitro, the in vivo impact of mCU activity may reveal Ca2+-mediated roles of mitochondria in brain signaling and metabolism. From in vitro studies of mitochondrial Ca2+ sequestration and cycling in various cell types of the central nervous system, we evaluated ranges of spontaneous and activity-induced Ca2+ distributions in multiple subcellular compartments in vivo. We hypothesized that inhibiting (or enhancing) mCU activity would attenuate (or augment) cortical neuronal activity as well as activity-induced hemodynamic responses in an overall cytoplasmic and mitochondrial Ca2+-dependent manner. Spontaneous and sensory-evoked cortical activities were measured by extracellular electrophysiology complemented with dynamic mapping of blood oxygen level dependence and cerebral blood flow. Calcium uniporter activity was inhibited and enhanced pharmacologically, and its impact on the multimodal measures were analyzed in an integrated manner. Ru360, an mCU inhibitor, reduced all stimulus-evoked responses, whereas Kaempferol, an mCU enhancer, augmented all evoked responses. Collectively, the results confirm aforementioned hypotheses and support the Ca2+ uptake-mediated integrative role of in vivo mitochondria on neocortical activity. PMID:23591650

  2. Uptake of Latex Particles by Blood Platelets

    PubMed Central

    White, James G.

    1972-01-01

    The incorporation of large particulates by blood platelets is considered identical to the ingestion of bacteria by neutrophils, and is referred to as platelet phagocytosis. However, bacteria enter neutrophils in sealed vacuoles derived from the cell wall, and products deposited in the vacuoles during neutrophil degranulation are confined almost exclusively to the phagolysosomes. Products released from platelet storage organelles after uptake of foreign particles, on the other hand, are extruded to the cell exterior. The basis for this unusual difference in the phagocytic response of platelets and neutrophils has been sought in the present investigation. Combined electron microscopic and cytechemical study of platelet-latexspherule interaction revealed that platelets do not phagocytize in the usual sense. Most of the latex particles observed in platelets were lodged in channels of the open canalicular system. Channels which contained latex did not pinch off to form sealed phagocytic vacuoles, but remained open. An electron-dense tracer, lanthanum nitrate, was able to penetrate into the channels and outline the ingested latex particles. Therefore, platelets do not phagocytize latex, but sequester the spherules in preformed membranous invaginations. The persistence of open channel communication with the exterior after latex uptake may explain why platelets extrude secretory products, rather than confine them to phagolysosomes. ImagesFig 4Fig 1Fig 5Fig 2Fig 6Fig 3 PMID:5086899

  3. Iodide uptake by negatively charged clay interlayers?

    PubMed

    Miller, Andrew; Kruichak, Jessica; Mills, Melissa; Wang, Yifeng

    2015-09-01

    Understanding iodide interactions with clay minerals is critical to quantifying risk associated with nuclear waste disposal. Current thought assumes that iodide does not interact directly with clay minerals due to electrical repulsion between the iodide and the negatively charged clay layers. However, a growing body of work indicates a weak interaction between iodide and clays. The goal of this contribution is to report a conceptual model for iodide interaction with clays by considering clay mineral structures and emergent behaviors of chemical species in confined spaces. To approach the problem, a suite of clay minerals was used with varying degrees of isomorphic substitution, chemical composition, and mineral structure. Iodide uptake experiments were completed with each of these minerals in a range of swamping electrolyte identities (NaCl, NaBr, KCl) and concentrations. Iodide uptake behaviors form distinct trends with cation exchange capacity and mineral structure. These trends change substantially with electrolyte composition and concentration, but do not appear to be affected by solution pH. The experimental results suggest that iodide may directly interact with clays by forming ion-pairs (e.g., NaI(aq)) which may concentrate within the interlayer space as well as the thin areas surrounding the clay particle where water behavior is more structured relative to bulk water. Ion pairing and iodide concentration in these zones is probably driven by the reduced dielectric constant of water in confined space and by the relatively high polarizability of the iodide species.

  4. Vaccine production, distribution, access, and uptake.

    PubMed

    Smith, Jon; Lipsitch, Marc; Almond, Jeffrey W

    2011-07-30

    For human vaccines to be available on a global scale, complex production methods, meticulous quality control, and reliable distribution channels are needed to ensure that the products are potent and effective at the point of use. The technologies used to manufacture different types of vaccines can strongly affect vaccine cost, ease of industrial scale-up, stability, and, ultimately, worldwide availability. The complexity of manufacturing is compounded by the need for different formulations in different countries and age-groups. Reliable vaccine production in appropriate quantities and at affordable prices is the cornerstone of developing global vaccination policies. However, to ensure optimum access and uptake, strong partnerships are needed between private manufacturers, regulatory authorities, and national and international public health services. For vaccines whose supply is insufficient to meet demand, prioritisation of target groups can increase the effect of these vaccines. In this report, we draw from our experience of vaccine development and focus on influenza vaccines as an example to consider production, distribution, access, and other factors that affect vaccine uptake and population-level effectiveness. PMID:21664680

  5. Microbiology and Moisture Uptake of Desert Soils

    NASA Astrophysics Data System (ADS)

    Kress, M. E.; Bryant, E. P.; Morgan, S. W.; Rech, S.; McKay, C. P.

    2005-12-01

    We have initiated an interdisciplinary study of the microbiology and water content of desert soils to better understand microbial activity in extreme arid environments. Water is the one constituent that no organism can live without; nevertheless, there are places on Earth with an annual rainfall near zero that do support microbial ecosystems. These hyperarid deserts (e.g. Atacama and the Antarctic Dry Valleys) are the closest terrestrial analogs to Mars, which is the subject of future exploration motivated by the search for life beyond Earth. We are modeling the moisture uptake by soils in hyperarid environments to quantify the environmental constraints that regulate the survival and growth of micro-organisms. Together with the studies of moisture uptake, we are also characterizing the microbial population in these soils using molecular and culturing methods. We are in the process of extracting DNA from these soils using MoBio extraction kits. This DNA will be used as a template to amplify bacterial and eukaryotic ribosomal DNA to determine the diversity of the microbial population. We also have been attempting to determine the density of organisms by culturing on one-half strength R2A agar. The long-range goal of this research is to identify special adaptations of terrestrial life that allow them to inhabit extreme arid environments, while simultaneously quantifying the environmental parameters that enforce limits on these organisms' growth and survival.

  6. Pathways of arsenic uptake and efflux.

    PubMed

    Yang, Hung-Chi; Fu, Hsueh-Liang; Lin, Yung-Feng; Rosen, Barry P

    2012-01-01

    Arsenic is the most prevalent environmental toxic substance and ranks first on the U.S. Environmental Protection Agency's Superfund List. Arsenic is a carcinogen and a causative agent of numerous human diseases. Paradoxically arsenic is used as a chemotherapeutic agent for treatment of acute promyelocytic leukemia. Inorganic arsenic has two biological important oxidation states: As(V) (arsenate) and As(III) (arsenite). Arsenic uptake is adventitious because the arsenate and arsenite are chemically similar to required nutrients. Arsenate resembles phosphate and is a competitive inhibitor of many phosphate-utilizing enzymes. Arsenate is taken up by phosphate transport systems. In contrast, at physiological pH, the form of arsenite is As(OH)(3), which resembles organic molecules such as glycerol. Consequently, arsenite is taken into cells by aquaglyceroporin channels. Arsenic efflux systems are found in nearly every organism and evolved to rid cells of this toxic metalloid. These efflux systems include members of the multidrug resistance protein family and the bacterial exchangers Acr3 and ArsB. ArsB can also be a subunit of the ArsAB As(III)-translocating ATPase, an ATP-driven efflux pump. The ArsD metallochaperone binds cytosolic As(III) and transfers it to the ArsA subunit of the efflux pump. Knowledge of the pathways and transporters for arsenic uptake and efflux is essential for understanding its toxicity and carcinogenicity and for rational design of cancer chemotherapeutic drugs.

  7. Mitochondrial calcium uptake capacity modulates neocortical excitability.

    PubMed

    Sanganahalli, Basavaraju G; Herman, Peter; Hyder, Fahmeed; Kannurpatti, Sridhar S

    2013-07-01

    Local calcium (Ca(2+)) changes regulate central nervous system metabolism and communication integrated by subcellular processes including mitochondrial Ca(2+) uptake. Mitochondria take up Ca(2+) through the calcium uniporter (mCU) aided by cytoplasmic microdomains of high Ca(2+). Known only in vitro, the in vivo impact of mCU activity may reveal Ca(2+)-mediated roles of mitochondria in brain signaling and metabolism. From in vitro studies of mitochondrial Ca(2+) sequestration and cycling in various cell types of the central nervous system, we evaluated ranges of spontaneous and activity-induced Ca(2+) distributions in multiple subcellular compartments in vivo. We hypothesized that inhibiting (or enhancing) mCU activity would attenuate (or augment) cortical neuronal activity as well as activity-induced hemodynamic responses in an overall cytoplasmic and mitochondrial Ca(2+)-dependent manner. Spontaneous and sensory-evoked cortical activities were measured by extracellular electrophysiology complemented with dynamic mapping of blood oxygen level dependence and cerebral blood flow. Calcium uniporter activity was inhibited and enhanced pharmacologically, and its impact on the multimodal measures were analyzed in an integrated manner. Ru360, an mCU inhibitor, reduced all stimulus-evoked responses, whereas Kaempferol, an mCU enhancer, augmented all evoked responses. Collectively, the results confirm aforementioned hypotheses and support the Ca(2+) uptake-mediated integrative role of in vivo mitochondria on neocortical activity.

  8. Abiotic uptake of gases by organic soils

    NASA Astrophysics Data System (ADS)

    Smagin, A. V.

    2007-12-01

    Methodological and experimental studies of the abiotic uptake of gaseous substances by organic soils were performed. The static adsorption method of closed vessels for assessing the interaction of gases with the solid and liquid soil phases and the dynamic method of determining the sorption isotherms of gases by soils were analyzed. The theoretical substantiation of the methods and their practical implementations on the basis of a PGA-7 portable gas analyzer (Russia) were considered. Good agreement between the equilibrium sorption isotherms of the gases and the Langmuir model was revealed; for the real ranges of natural gas concentrations, this model can be reduced to the linear Henry equation. The limit values of the gas sorption (Langmuir monolayer capacity) are typical for dry samples; they vary from 670 4000 g/m3 for methane and oxygen to 20 000 25 000 g/m3 for carbon dioxide. The linear distribution coefficients of gases between the solid and gas phases of organic soils (Henry constants) are 8 18 units for poorly sorbed gases (O2, CH4) and 40 60 units for CO2. The kinetics of the chemicophysical uptake of gases by the soil studied is linear in character and obeys the relaxation kinetic model of the first order with the corresponding relaxation constants, which vary from 1 h -1 in wet samples to 10 h -1 in dry samples.

  9. Iron uptake and transport across physiological barriers.

    PubMed

    Duck, Kari A; Connor, James R

    2016-08-01

    Iron is an essential element for human development. It is a major requirement for cellular processes such as oxygen transport, energy metabolism, neurotransmitter synthesis, and myelin synthesis. Despite its crucial role in these processes, iron in the ferric form can also produce toxic reactive oxygen species. The duality of iron's function highlights the importance of maintaining a strict balance of iron levels in the body. As a result, organisms have developed elegant mechanisms of iron uptake, transport, and storage. This review will focus on the mechanisms that have evolved at physiological barriers, such as the intestine, the placenta, and the blood-brain barrier (BBB), where iron must be transported. Much has been written about the processes for iron transport across the intestine and the placenta, but less is known about iron transport mechanisms at the BBB. In this review, we compare the established pathways at the intestine and the placenta as well as describe what is currently known about iron transport at the BBB and how brain iron uptake correlates with processes at these other physiological barriers. PMID:27457588

  10. Uptake and partitioning of zinc in Lemnaceae.