Search results for "Microdialysi"
showing 10 items of 73 documents
Behavioral deficits induced by lead exposure are accompanied by serotonergic and cholinergic alterations in the prefrontal cortex
2013
The effects of long-term lead (Pb) exposure producing a blood Pb concentration of lower than 20 μg/dL, i.e. below that associated with overt neurological deficits in occupationally exposed individuals, was studied in adult rats. In order to assess gender differences, we performed parallel behavioral experiments in male and female rats. Exposure to Pb acetate (50 ppm in drinking water) for 6 months induced motor and cognitive alterations, however these effects were gender- and task-dependent. Chronic lead exposure impaired spatial learning assessed in the Morris water maze test (MWM) in both genders, whereas it only induced hyperactivity in the open field and impaired motor coordination in t…
The effects of nitric oxide on striatal serotoninergic transmission involve multiple targets: an in vivo microdialysis study in the awake rat
2004
Abstract The role of endogenous nitric oxide (NO) in N -methyl- d -aspartate (NMDA)-induced modulation of serotonin (5-HT) release in the striatum of freely moving rats has been studied using microdialysis technique. NMDA-induced increase in 5-HT release was significantly inhibited by selective nitric oxide synthase (nNOS) inhibitor S -methylthiocitrulline (S-Me-TC), ONOO − scavenger l -cysteine ( l -cys), and guanylate cyclase (GC) inhibitor 1 H [1,2,4]oxadiazolo[4,3- a ]quinoxalin-1-one (ODQ). These data suggest that modulation of 5-HT levels is linked to the formation of NO produced by NMDA receptor activation and that endogenously produced NO increases 5-HT concentrations both by stimul…
Differential effect of beta-N-oxalylamino-L-alanine, the Lathyrus sativus neurotoxin, and (+/-)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate …
2000
We studied the effect of beta-oxalylamino-L-alanine, a glutamate analog present in Lathyrus sativus seeds and implicated in the etiopathogenesis of neurolathyrism, and (+/-)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate on the extracellular levels of aspartate, glutamate and taurine in the primary motor cortex of freely moving rats. We found that while both neurotoxins increase the level of aspartate and glutamate, only (+/-)-alpha(-amino-3-hydroxy-5-methylisoxazole-4-propionate is able to modulate the level of taurine. GYKI-52466, a non-competitive non-NMDA antagonist, inhibited beta-oxalylamino-L-alanine-induced increase of aspartate, but not that of glutamate. Conversely, this ant…
Environmental enrichment promotes neurogenesis and changes the extracellular concentrations of glutamate and GABA in the hippocampus of aged rats.
2005
The aim of the present study was to investigate the effects of environmental enrichment on the neurogenesis and the extracellular concentrations of glutamate and GABA in the hippocampus of freely moving young and aged rats. Male Wistar rats of 2 (young) and 25 (old) months of age were housed during 8 weeks in an enriched environment; control rats were kept in individual plastic cages during that same period of time. Rats were injected intraperitoneally with bromodeoxyuridine (BrdU; 40 mg/kg; 7 days) during the fourth week of the housing period to detect neurogenesis in the dentate gyrus (DG) of the hippocampus. Rats were sacrified 6 weeks after the last injection of BrdU. During the last we…
The neuroprotective effect of lactate is not due to improved glutamate uptake after controlled cortical impact in rats.
2012
For many years lactate was considered to be a waste product of glycolysis. Data are accumulating that suggest that lactate is an important energy substrate for neurons during activation. In severe traumatic brain injury (TBI) glutamate release and ischemic cerebral blood flow (CBF) are major factors for a mismatch between energy demand and supply and for neuronal cell death. Although ATP and behavior could be improved by lactate treatment after TBI, no histological correlate nor any linkage to better astrocytic glutamate uptake or CBF as possible mechanisms have been described. We subjected male rats to a controlled cortical impact (CCI; 5 m/sec, 2.5 mm). To study the effects of lactate tre…
Mesolimbic dopaminergic system activity as a function of food reward: A microdialysis study
1996
The mesolimbic dopaminergic system (MDS) has been shown to be implicated in feeding behaviors. The present experiment was conducted to examine the effects of the sensory properties of food ingested on MDS activity. Microdialysis coupled to high-performance liquid chromatography with electrochemical detection was employed to measure the extracellular levels of dopamine (DA) and its main metabolites (DOPAC and HVA) in the nucleus accumbens of freely moving rats. During microdialysis sessions rats had access or not to powdered foods varying in palatability: short cakes as highly palatable (HP) food and regular chow as low palatable (LP) food. In the absence of food, there were no alterations i…
A homeostatic mechanism counteracting K+-evoked choline release in adult brain
2002
Choline (Ch) is an essential nutrient as the biosynthetic precursor of acetylcholine (ACh) and phospholipids. Under resting conditions, the intracellular accumulation of Ch (above 10-fold), which is positively charged, is governed by the membrane potential and follows the Nernst equation. Accordingly, in synaptosomes from adult rats during depolarization, we observed a linear relationship between release of free cytoplasmic Ch and KCl concentration (2.7-120 mm). The K(+) -evoked Ch release was Ca(2+) -independent and did not originate from ACh or phospholipid hydrolysis. In superfused brain slices of adult rats, however, a K(+) -induced Ch efflux was absent. Also, under in vivo conditions, …
Hippocampal dopamine receptors modulate the motor activation and the increase in dopamine levels in the rat nucleus accumbens evoked by chemical stim…
2005
A number of studies have shown that chemical stimulation (using N-methyl-D-aspartate (NMDA) infusions) or electrical stimulation of the ventral hippocampus (VH) elicits locomotor activation and sustained increases in nucleus accumbens (NAc) dopamine (DA) levels in rodents. How DA neurotransmission in NAc is involved in these effects has also been well established. However, the modulatory role of the DA receptors located in VH is not yet fully understood. The purpose of this study was to characterize the role played by VH D1 and D2 subtype receptors in both the locomotor activation and NAc DA increases induced by NMDA stimulation of the VH. This was assessed by studying how retrodialysis app…
Hippocampal dopamine receptors modulate cFos expression in the rat nucleus accumbens evoked by chemical stimulation of the ventral hippocampus
2005
Recently, we have shown that D1 and D2 receptors in the ventral hippocampus (VH) modulate both the locomotor activation and the increase in dopamine (DA) levels in the rat nucleus accumbens (NAc) induced by NMDA stimulation of the VH. In the present study we analyze the possible role of VH D1 and D2 receptors in the modulation of the cFos expression in NAc (core and shell subregions) and in dorsal striatum. This was assessed by immunohistochemical analysis of cFos expression in the rat brains after retro-dialysis application of NMDA (50mM, 10 min) into VH, in absence and in presence of either the D1/D5 receptor antagonist SCH 23390 (100 and 250 microM, 60 min) or the D2 receptor antagonist …
Molecular and functional interactions between tumor necrosis factor-alpha receptors and the glutamatergic system in the mouse hippocampus: Implicatio…
2009
Tumor necrosis factor (TNF)-alpha is a proinflammatory cytokine acting on two distinct receptor subtypes, namely p55 and p75 receptors. TNF-alpha p55 and p75 receptor knockout mice were previously shown to display a decreased or enhanced susceptibility to seizures, respectively, suggesting intrinsic modifications in neuronal excitability. We investigated whether alterations in glutamate system function occur in these naive knockout mice with perturbed cytokine signaling that could explain their different propensity to develop seizures. Using Western blot analysis of hippocampal homogenates, we found that p55(-/-) mice have decreased levels of membrane GluR3 and NR1 glutamate receptor subuni…