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J B Gramsbergen

Publications and source records attributed to J B Gramsbergen.

At least 19 recordsLinked to original sources
PubMed2000

Pyruvate protects against 3-nitropropionic acid neurotoxicity in corticostriatal slice cultures.

Previously, we have shown that 3-nitropropionic acid (NPA) neurotoxicity in organotypic corticostriatal slice cultures is dependent on glucose and glutamate. Here we studied the neuroprotective potential of agents improving mitochondrial function, including creatine, malate, oxaloacetate, Pyruvate and L-lactate in NPA-treated slice cultures. pyruvate provided the best protection against the loss of glutamic acid decarboxylase activity, depletion of GABA levels, increased propidium iodide uptake and increased glial fibrillary acidic protein levels. ATP levels were significantly reduced by 100 microM NPA (but not by 50 microM) and restored by pyruvate (5 mM). Creatine and L-lactate had no significant protective effect. Protective mechanisms of pyruvate are probably multifold, including stimulation of the citric acid cycle, scavenging and reduction of excitotoxicity.

Adenosine Triphosphate↗
PubMed2000

Improved survival of embryonic porcine dopaminergic neurons in coculture with a conditionally immortalized GDNF-producing hippocampal cell line.

Transplantation of embryonic nigral tissue is used as an experimental therapy for patients with Parkinson's disease but is hampered by a limited survival rate of dopaminergic neurons. Glial cell line-derived neurotrophic factor (GDNF) is a potent survival factor for nigrostriatal dopaminergic neurons, and the present in vitro study aimed at improving the survival of dopaminergic neurons in porcine mesencephalic brain slice cultures by adding transfected, immortalized, temperature-sensitive GDNF-releasing HiB5 cells (HiB5-GDNF). Embryonic (E27/28) porcine ventral mesencephalic brain slices were placed on membrane inserts in six-well plates with serum-containing medium, and HiB5-GDNF, nontransfected HiB5 cells (HiB5-control), or green fluorescent protein-producing HiB5 cells (HiB5-GFP) were seeded onto each tissue slice. The concentration of GDNF in the coculture medium was 0.49 +/- 0.13 ng/ml at day 9 and 0. 22 +/- 0.05 ng/ml at day 19 (mean +/- SEM) as measured by GDNF ELISA. The decrease in release of GDNF over time was paralleled by a gradual reduction in the number of HiB5-GFP cells expressing the reporter gene (EGFP). At day 12, HPLC analysis revealed that medium from HiB5-GDNF cocultures contained 2.0 times more dopamine than medium from HiB5-control cocultures. At day 21 there was 1.6 times more dopamine. Similar results were obtained for the dopamine metabolite 3,4-dihydroxyphenylacetic acid. At day 21, cell counts showed that HiB5-GDNF cocultures contained 1.5 times more tyrosine hydroxylase immunoreactive neurons than HiB5-control cocultures, which must be compared with a 1.8 fold increase after chronic treatment with rhGDNF (10 ng/ml). In conclusion, the better survival of HiB5-GDNF cocultures is promising for the generation of effective cell lines for local delivery of neurotrophic factors to intracerebral nigral grafts.

3,4-Dihydroxyphenylacetic Acid↗
PubMed2000

3-Nitropropionic acid neurotoxicity in organotypic striatal and corticostriatal slice cultures is dependent on glucose and glutamate.

Mitochondrial inhibition by 3-nitropropionic acid (3-NPA) causes striatal degeneration reminiscent of Huntington's disease. We studied 3-NPA neurotoxicity and possible indirect excitotoxicity in organotypic striatal and corticostriatal slice cultures. Neurotoxicity was quantified by assay of lactate dehydrogenase in the medium and glutamic acid decarboxylase in tissue homogenates. 3-NPA toxicity (25-100 microM in 5 mM glucose, 24-48 h) appeared to be highly dependent on culture medium glucose levels. 3-NPA treatment caused also a dose-dependent lactate increase, reaching a maximum of threefold increase above control at 100 microM. Both a high dose of glutamate (5 mM) and glutamate uptake blockade by dl-threo-beta-hydroxyaspartate potentiated 3-NPA neurotoxicity in corticostriatal slice cultures. Furthermore, striatum from corticostriatal cocultures was more sensitive to 3-NPA than striatum without cortex and tetrodotoxin, MK-801, and d-2-amino-5-phosphonopentanoic acid prevented or attenuated 3-NPA neurotoxicity, suggesting that membrane depolarization and/or neuronal activity of the glutamatergic corticostriatal pathway contributes to striatal pathology. The results indicate that in vivo characteristics of 3-NPA toxicity can be reproduced in organotypic corticostriatal slice cultures.

Animals↗
PubMed1999

Excitotoxic effects of non-NMDA receptor agonists in organotypic corticostriatal slice cultures.

The excitotoxic effects of the glutamate receptor agonists kainic acid (KA) and 2-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) and the corresponding neuroprotective effects of the AMPA/KA receptor antagonist 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo(F)quinoxaline (NBQX) were examined in corticostriatal slice cultures. The purpose was to examine the feasibility of these cultures for excitotoxic studies, and to demonstrate possible differential excitotoxic effects of KA and AMPA on striatal and cortical neurons. Slices of dorsolateral striatum with overlying neocortex were obtained from neonatal rats and grown on semiporous membranes in serum-free medium for 3-4 weeks before exposure to KA or AMPA for 48 h. The uptake by injured cells of the fluorescent dye propidium iodide (PI) added to the culture medium was used as a quantifiable measure for neuronal degeneration and compared with efflux of the cytosolic enzyme lactate dehydrogenase (LDH) into the culture medium and loss of glutamic acid decarboxylase (GAD) activity in the tissue. Histological sections were also stained by the fluorescent dye Fluoro-Jade (FJ), for degenerating neurons and by immunocytochemical staining for gamma-aminobutyric acid (GABA). Digitized images showed a dose (0-24 microM KA, 0-6 microM AMPA) and time (0-48 h) dependent increase in PI uptake in both striatum and cortex. In other cultures exposed to KA (24 microM) or AMPA (6 microM) together with NBQX (0.1-9 microM), NBQX was found to exert a differential neuroprotective effect on striatum and cortex at low doses. NBQX was thus more protective against KA in the cortex than in the striatum, while the opposite was seen in relation to AMPA. Regarding neurodegenerative markers, PI uptake was significantly correlated with (1) LDH release into the culture medium, (2) optical density of Fluoro-Jade staining, (3) loss of GAD-activity in tissue homogenates, and (4) loss of GABA-immunostained neurons. We conclude that both differences between compounds (AMPA vs. KA) and brain areas (striatum vs. cortex) can be demonstrated in corticostriatal slice cultures, which in conjunction with an established set of markers for neuronal cell damage appears to be a feasible model for studies of the neurotoxic and neuroprotective effects of glutamate receptor agonists and antagonists.

Animals↗
PubMed1998

Trimethyltin (TMT) neurotoxicity in organotypic rat hippocampal slice cultures.

The neurotoxic effects of trimethyltin (TMT) on the hippocampus have been extensively studied in vivo. In this study, we examined whether the toxicity of TMT to hippocampal neurons could be reproduced in organotypic brain slice cultures in order to test the potential of this model for neurotoxicological studies, including further studies of neurotoxic mechanisms of TMT. Four-week-old cultures, derived from 7-day-old donor rats and grown in serum-free medium, were exposed to TMT (0.5-100 microM) for 24 h followed by 24 h in normal medium. TMT-induced neurodegeneration was then monitored by (a) propidium iodide (PI) uptake, (b) lactate dehydrogenase (LDH) efflux into the culture medium, (c) cellular cobalt uptake as an index of calcium influx, (d) ordinary Nissl cell staining, and (e) immunohistochemical staining for microtubule-associated protein 2 (MAP-2). Cellular degeneration as assessed by densitometric measurements of PI uptake displayed a dose and time-dependent increase, with the following ranking of vulnerability of the hippocampal subfields: FD>CA4>/=CA3c>CA1>CA3ab. This differential neuronal vulnerability observed by PI uptake was confirmed by MAP-2 immunostaining and corresponded to in vivo cell stain observations of rats acutely exposed to TMT. The mean PI uptake of the cultures and the LDH efflux into the medium were highly correlated. The combined results obtained by the different markers indicate that the hippocampal slice culture method is a feasible model for further studies of TMT neurotoxicity.

Animals↗
PubMed1997

Brain-specific modulation of kynurenic acid synthesis in the rat.

This study was designed to investigate modulatory mechanisms that control the synthesis of the neuroprotective endogenous excitatory amino acid receptor antagonist kynurenate. De novo kynurenate formation was examined in vitro using tissue slices from rat brain, liver, and kidney. In slices from adult cerebral cortex, veratridine, quisqualate, and L-alpha-aminoadipate decreased kynurenate synthesis substantially. Glucose removal or changes in the ionic milieu, too, influenced kynurenate formation significantly, suggesting that demands on cellular energy interfere with kynurenate production in the adult rat brain. The effects of quisqualate and L-alpha-aminoadipate were also observed in the immature brain, in the quinolinate-lesioned adult striatum, and, to a lesser extent, in peripheral organs. In contrast, the effect of veratridine was not seen in the lesioned brain or in kidney and liver tissue, indicating its dependency on intact neuron-glia interactions. Compared with the normal adult brain, ionic manipulations yielded qualitatively distinct results in the developing brain and in the periphery, but their effects remained unchanged in the lesioned striatum. Glucose deprivation was less consequential in the immature than in the adult brain and was entirely ineffective in the lesioned striatum and in the periphery. These results further link cellular, especially astrocytic, energy metabolism to kynurenate formation in the brain. More generally, the existence of brain-specific mechanisms for the regulation of kynurenate production is suggestive of a modulatory role of this metabolite in excitatory amino acid receptor function and dysfunction.

2-Aminoadipic Acid↗
PubMed1996

Manganese-induced hydroxyl radical formation in rat striatum is not attenuated by dopamine depletion or iron chelation in vivo.

The present studies were aimed at investigating the possible roles of dopamine (DA) and iron in production of hydroxyl radicals (OH) in rat striatum after Mn2+ intoxication. For this purpose, DA depletions were assessed concomitant with in vivo 2,3- and 2,5-dihydroxybenzoic acid (DHBA) formation from the reaction of salicylate with OH, of which 2,3-DHBA is a nonenzymatic adduct. Following intrastriatal Mn2+ injection, marked 2,3-DHBA increases were observed in a time- and dose-dependent fashion reaching maximum levels at 6-18 h and a plateau beyond 0.4 micromol (fourfold increase). The delayed increase of 2,3-DHBA levels suggestS that Mn2+ induces OH formation in the living brain by an indirect process. The early DA depletion (2 h) and relatively late OH formation (6 h) indicate independent processes by Mn2+. In addition, depletion of DA (about 90%) by reserpine pretreatment not significantly alter Mn2+-induced 2,3-DHBA formation or the extent of DA depletion, suggesting that DA or DA autoxidation are not participating in Mn2+-induced OH formation in vivo. Furthermore, Mn2+ injection did not significantly alter the low molecular weight weight iron pool in striatum, and co-injections of the iron-chelator deferoxamine with Mn(2+) into striatum did not significantly attenuate Mn(2+)-induced 2,3-DHBA formation. These findings suggest no role of chelatable iron in generation of Mn(2+)-induced OH, but do not exclude a role for mitochondrial heme-iron or peroxynitrite (Fe-indepeNdent) in Mn2+-induced OH formation.

Animals↗
PubMed1995

Detection of salicylate and its hydroxylated adducts 2,3- and 2,5-dihydroxybenzoic acids as possible indices for in vivo hydroxyl radical formation in combination with catechol- and indoleamines and their metabolites in cerebrospinal fluid and brain tissue.

It has been suggested that salicylate (SA) hydroxylation can be used to detect hydroxyl radical formation in vivo. Here we describe a rapid and sensitive HPLC method using ultraviolet absorbance (UV) and electrochemical detection (EC) to detect SA (UV), its hydroxylated adducts 2,3- and 2,5-dihydroxybenzoic acids (DHBA) and catechol in combination with catechol- and indoleamines and related metabolites (EC) in one isocratic run. These compounds were measured in acidified cerebrospinal fluid (CSF) and perchlorate extracts of striatal tissues of untreated and SA-loaded rats (300 mg/kg SA, i.p.). Peaks were identified by comparing retention times of samples and standards, by adding standards to biological samples, by voltamograms, and by comparing chromatograms of manganese (Mn2+)-injected striata of SA-loaded rats with several control conditions. Six hours after unilateral injection of 0.4 mumol Mn2+ into striatum, 2,3-DHBA and 2,5-DHBA levels in striatum were respectively 4- and 7-fold increased as compared to non-injected (contralateral) striata, suggesting in vivo hydroxyl radical formation. In addition, dopamine and serotonin levels were depleted in Mn(2+)-injected striata by 46% and 64%, respectively. In CSF of Mn(2+)-injected rats, DHBA/SA ratios were not significantly changed as compared to those of control rats. In conclusion, the described technique can be applied to study in vivo hydroxyl radical formation in direct relation with dopaminergic and serotonergic neurotransmitter changes during neurotoxic processes.

Animals↗
PubMed1994

Regional and temporal profiles of calcium accumulation and glial fibrillary acidic protein levels in rat brain after systemic injection of kainic acid.

Cerebral calcium accumulation and increases in the astroglial intermediate filament protein, glial fibrillary acidic protein (GFAP), have been used as markers of neurotoxic and ischemic brain damage. The present study was aimed at quantitatively investigating the regional and temporal relationship of those indices following a neurotoxic insult. For this purpose, regional changes in 45Ca uptake and GFAP levels, using ELISA, were evaluated in rat brains at both early (several hours) and late time points (up to 6 months) after a single systemic injection of kainic acid (12 mg/kg). After 4 h, limbic brain areas were already heavily labelled by 45Ca. In most investigated brain areas 45Ca accumulation peaked at day 4 (maximum 5 fold increase in amygdala) and returned to normal levels within 1 week (cerebellum, pons/medulla, occipital cortex), 2 weeks (striatum, frontal cortex), 2 or 4 months (limbic brain areas), or remained significantly elevated until 6 months (thalamus). In contrast, in all investigated brain areas, except cerebellum and pons/medulla, GFAP was increased from day 2, reaching maximum levels at day 28 in most limbic structures and remained significantly elevated at the same high level (15 fold increase) in amygdala, or somewhat lower levels in other affected regions (2-7 fold), but not in the thalamus. In all brain areas with 45Ca accumulation, GFAP was increased and the peak responses were highly correlated. Thus, both indices are useful quantitative biochemical markers of acute or subchronic neurotoxicity.

Animals↗
PubMed1994

Axonal transport of manganese and its relevance to selective neurotoxicity in the rat basal ganglia.

The present study provides evidence for anterograde axonal transport of manganese (Mn) in the basal ganglia. Microinjections of 54Mn into rat substantia nigra or striatum revealed region-specific accumulation and retention of the isotope in globus pallidus, striatum, thalamus and substantia nigra for up to at least 48 or 72 h respectively. Within 4 h after intrastriatal injection of 54Mn, radioactivity accumulated in the substantia nigra, suggesting axonal transport of the metal. Subsequent studies using bilateral 54Mn injections into striatum or substantia nigra and unilateral colchicine injections into or transection of the medial forebrain bundle confirmed axonal transport of Mn through these fibres. Selective destruction of the striatonigral or nigrostriatal pathways using quinolinic acid or 6-hydroxydopamine 2 weeks before injection of the isotope, revealed uptake of 54Mn by cell bodies of both gamma-aminobutyric acidergic striatal and dopaminergic nigral neurons and subsequent anterograde transport through striatonigral or nigrostriatal fibres. In addition, the quinolinic acid-lesioned striatum retained three times more radioactivity than the intact striatum. In conclusion, the present data suggest that both glial cells and striatonigral and nigrostriatal neurons are potential targets for Mn toxicity. These results and the selective neurotoxicity of Mn are discussed with respect to the iron transport protein transferrin, transferrin receptors, the iron storage protein ferritin, and mitochondrial dysfunction.

Animals↗
PubMed1994

45CaCl2 autoradiography in brain from rabbits with encephalopathy from acute liver failure or acute hyperammonemia.

In experimental hepatic encephalopathy and hyperammonemia, extracellular levels of glutamate are increased in hippocampus and cerebral cortex. It has been suggested that overstimulation of glutamate receptors causes a pathological entry of calcium into neurons via receptor-operated (NMDA- and AMPA-type) or voltage-dependent calcium channels leading to calcium overload and cell death. Neurodegeneration as a result of exposure to excitotoxins, including glutamate, can be localized and quantified using 45CaCl2 autoradiography. This approach was used to study cerebral calcium accumulation in rabbits with acute liver failure and acute hyperammonemia. Acute liver failure was induced in 6 rabbits, acute hyperammonemia in 4 rabbits; 4 control rabbits received sodium-potassium-acetate. At the start of the experiment 500 microCi 45CaCl2 was given intravenously. After development of severe encephalopathy, the animals were killed by decapitation. All rabbits with acute liver failure or acute hyperammonemia developed severe encephalopathy, after 13.2 +/- 1.7 and 19.3 +/- 0.5 hours respectively (mean +/- SEM). Plasma ammonia levels were 425 +/- 46 and 883 +/- 21 mumol/l, respectively (p < 0.05). Control rabbits maintained normal plasma ammonia levels (13 +/- 5 mumol/l), demonstrated normal behaviour throughout the study and were sacrificed after 16 hours. 45Ca(2+)-autoradiograms of 40 microns brain sections were analyzed semiquantitatively using relative optical density and computerized image analysis. As compared to background levels 45Ca was not increased in hippocampus or any other brain area of rabbits with severe encephalopathy from acute liver failure or acute hyperammonemia. This suggests that, despite increased extracellular brain glutamate levels in these conditions, glutamate neurotoxicity was not important for the development of encephalopathy in these rabbits.

Acetates↗
PubMed1994

Selective lesions by manganese and extensive damage by iron after injection into rat striatum or hippocampus.

Regional 45Ca2+ accumulation and analysis of monoamines and metabolites in dissected tissues were used to localize, quantify, and characterize brain damage after intracerebral injections of Mn2+ into striatum and hippocampus. The specificity of Mn(2+)-induced lesions is described in relation to brain damage produced by local Fe2+ or 6-hydroxydopamine (6-OHDA) injections. In striatum, Fe2+ and Mn2+ produced dose-dependent (0.05-0.8 mumol) dopamine (DA) depletion, with Fe2+ being 3.4 times more potent than Mn2+. Studies examining the time course of changes in monoamine levels in striatum following local application of 0.4 mumol of Mn2+ revealed maximal depletion of all substances investigated (except 5-hydroxyindoleacetic acid) after 3 days. The effects on DA (87% depletion at day 3) and its major metabolites were most pronounced and lasted until at least 90 days (40% depletion), whereas serotonin and noradrenaline levels recovered within 21 and 42 days, respectively. In addition, levels of 3-methoxytyramine, which is used as an index of DA release, also recovered within 42 days, indicating a functional restoration of DA neurotransmission despite substantial loss of DA content. Intrastriatal Mn2+ (0.4 mumol) produced time-dependent 45Ca2+ accumulation in striatum, globus pallidus, entopeduncular nucleus, several thalamic nuclei, and substantia nigra pars reticulata ipsilateral to the injection site. In contrast, 6-OHDA injected at a dose equipotent in depleting DA produced significantly less 45Ca2+ accumulation in striatum and globus pallidus and no labeling of other brain areas, whereas Fe2+ (0.4 mumol) produced extensive 45Ca2+ accumulation throughout basal ganglia, accumbens, and cerebral cortex. In hippocampus, high Mn2+ (0.4 mumol) produced limited 45Ca2+ accumulation in subiculum and dentate gyrus, whereas low Fe2+ (0.1 mumol) produced widespread 45Ca2+ accumulation throughout hippocampus, thalamus, and cerebral cortex. It is concluded that (a) Mn2+ is selectively neurotoxic to pathways intrinsic to the basal ganglia, (b) intrastriatal injections can be used as a model for systemic Mn2+ intoxications, and (c) high endogenous Fe3+ and/or catecholamine levels potentiate the neurotoxicity of Mn2+.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1993

Time- and dose-dependent 45Ca2+ accumulation in rat striatum and substantia nigra after an intrastriatal injection of quinolinic acid.

To evaluate the use of cerebral 45Ca accumulation as an index for neurotoxic brain damage, the dose and time dependency of regional 45Ca accumulation in the rat brain following an unilateral injection of quinolinic acid (QUIN) into the striatum was investigated. Accumulation of radioactivity was assessed 6 h or 1, 2, 7, 21, 42, and 84 days after QUIN and 6 h or 1 day after ip 45CaCl2 injection using liquid scintillation counting of dissected brain tissues and semiquantitative autoradiography of brain sections. Dissected striata were also used for assay of glutamic acid decarboxylase (GAD) activity and after autoradiography brain sections were stained with thionine or for cholinesterase. One week after QUIN (0-50 micrograms) a dose-dependent increase in 45Ca accumulation in the injected striatum and the ipsilateral substantia nigra, but not in frontal cortex or cerebellum, was observed. In addition, 45Ca accumulation and GAD reduction in the striatum was highly significantly correlated. In the striatum 45Ca accumulated rapidly within 48 h and after this time point--by this time GAD had reached a minimum--the 45Ca content continued to increase in the lesioned striatum until Day 42. Six hours after QUIN 45Ca accumulated in the immediate vicinity of the injection site, whereas the increase 6 weeks later is primarily due to accumulation of 45Ca in striatal tissue more remote from the injection site. In the ipsilateral substantia nigra 45Ca accumulation reached a maximum 7 days after QUIN, probably reflecting delayed transneuronal death rather than degeneration of striatonigral nerve terminals.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Age-related changes in kynurenic acid production in rat brain.

Two separate in vitro assays were used to examine the biosynthesis of the broad spectrum excitatory amino acid receptor antagonist kynurenic acid (KYNA) during the life span of the adult rat. Assessment of KYNA's anabolic enzyme kynurenine aminotransferase revealed steady increases between 3 and 24 months of age in all five brain regions examined. No changes were observed in the liver. The changes were particularly pronounced in the cortex and in the striatum where enzyme activity increased three-fold during the period studied. KYNA production from its bioprecursor L-kynurenine was also investigated in tissue slices and was found to be significantly enhanced in the cortex and hippocampus of old animals. The effect of depolarizing agents or sodium replacement was virtually identical in tissues from young and old rats. These data, which are in excellent agreement with reports on an age-dependent increase of KYNA concentration in brain tissue, suggest an enhanced KYNA tone in the aged brain. Together with the reported decline in cerebral excitatory amino acid receptor densities with age, increased production of KYNA may play a role in cognitive and memory dysfunction in old animals.

Aging↗