Search results for "aspartate"
showing 10 items of 195 documents
Acute ammonia toxicity is mediated by the NMDA type of glutamate receptors
1992
AbstractPrevious experiments in our laboratory suggested that ammonium toxicity could be mediated by the NMDA type of glutamate receptors. To assess this hypothesis we tested if MK-801, a specific antagonist of the NMDA receptor, is able to prevent ammonium toxicity. Mice and rats were injected i.p. with 12 and 7 mmol/kg of ammonium acetate, respectively, 73% of the mice and 70% of the rats died. However, when the animals were injected i.p. with 2 mg/kg of MK-801, 15 min before ammonium injection, only 5% of the mice and 15% of the rats died. The remarkable protection afforded by MK-801 indicates that ammonia toxicity is mediated by the NMDA receptor.
A Sequential Algorithm Combining ADAPT and Liver Stiffness Can Stage Metabolic-Associated Fatty Liver Disease in Hospital-Based and Primary Care Pati…
2020
INTRODUCTION Metabolic-associated fatty liver disease is common, with fibrosis the major determinant of adverse outcomes. Population-based screening tools with high diagnostic accuracy for the staging of fibrosis are lacking. METHODS Three independent cohorts, 2 with both liver biopsy and liver stiffness measurements (LSMs, n = 254 and 65) and a population sample (n = 713), were studied. The performance of a recently developed noninvasive algorithm (ADAPT [age, diabetes, PRO-C3 and platelets panel]) as well as aspartate aminotransferase-to-platelet ratio index, fibrosis-4, nonalcoholic fatty liver disease fibrosis score, and LSM was used to stage patients for significant (≥F2) and advanced …
Role of N-methyl-D-aspartate receptors in the long-term effects of repeated social defeat stress on the rewarding and psychomotor properties of cocai…
2019
Abstract Exposure to social stress increases the vulnerability of experimental animals to the rewarding effects of cocaine and it has been suggested that the glutamatergic system could be involved in these effects of stress. The aim of this work is to determine the role of N-methyl- d -aspartate (NMDA) glutamate receptors in the influence of social stress on the conditioned place preference and locomotor sensitization induced by cocaine. Mice treated with saline or NMDA antagonist memantine (5 or 10 mg/kg) underwent repeated social defeat or were kept in the exploration control condition. After three weeks, all groups (SAL + RSD, M5 + RSD, M10 + RSD, SAL + EXP, M5 + EXP and M10 + EXP) were …
Giant hepatic hydatid cyst as a cause of small bowel obstruction.
2006
Today, giant hydatid cysts are fairly rare even in endemic areas. We describe a case of an extremely large hydatid cyst of the liver that was causing massive compression of the neighboring organs, giving rise to a subocclusive syndrome of the intestine. After considering the various approaches available for the treatment of this disease, it was decided that radical surgery was still the best therapeutic choice, especially when extremely large cysts are involved. In particular, in clinical situations where it is difficult to perform radical surgical procedures, less aggressive surgery followed by drug treatment should be the treatment of choice.
NMDA receptor antagonist felbamate reduces behavioral deficits and blood-brain barrier permeability changes after experimental subarachnoid hemorrhag…
2007
Increased levels of glutamate and aspartate have been detected after subarachnoid hemorrhage (SAH) that correlate with neurological status. The NMDA receptor antagonist felbamate (FBM; 2-phenyl-1,3-propanediol dicarbamate) is an anti-epileptic drug that elicits neuroprotective effects in different experimental models of hypoxia-ischemia. The aim of this dose-response study was to evaluate the effect of FBM after experimental SAH in rats on (1) behavioral deficits (employing a battery of assessment tasks days 1-5 post-injury) and (2) blood-brain barrier (BBB) permeability changes (quantifying microvascular alterations according to the extravasation of protein-bound Evans Blue by a spectropho…
Nitric oxide and glutamate interaction in the control of cortical and hippocampal excitability.
1999
Summary: Purpose: We investigated the role of nitric oxide (NO) as a new neurotransmitter in the control of excitability of the hippocampus and the cerebral cortex, as well as the possible functional interaction between NO and the glutamate systems. Methods: The experiments were performed on anesthetized rats. The bioelectrical activities of the somatosensory cortex and the CA1 region of the hippocampus of these rats were recorded. Pharmacologic inhibition of NO synthase (NOS) through the nonselective and brain-selective inhibitors, N-nitro-L-arginine methyl ester (l-NAME) and 7-nitroindazole (7-NI), was performed. Results: The treatments caused the appearance of an interictal discharge act…
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…
Effects of excitatory amino acids and neuropeptide Y on the discharge activity of suprachiasmatic neurons in rat brain slices
1997
Effects of L-glutamate, AMPA, NMDA and NPY on the discharge activity of neurons located in the ventral subdivision of the suprachiasmatic nucleus were examined in submerged coronal slices of the rat hypothalamus. All substances were bath applied. Application of L-glutamate (14 neurons examined) induced an excitatory response in 8 suprachiasmatic neurons (+248.9 +/- 122.24%, mean +/- S.E.M.; P0.001). A biphasic response, i.e. an initial transient excitation (+54.3 +/- 8.21%; P0.001) succeeded by an inhibition (-66.2 +/- 9.31%; P0.001), was observed in 6 neurons. Application of AMPA (36 neurons examined) resulted in an excitation of 31 neurons (+209.2 +/- 58.58%; P0.0001). Application of NMDA…
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 …
Dose-dependent effect of S(+) ketamine on post-ischemic endogenous neurogenesis in rats.
2009
Background: Ketamine is a non-competitive antagonist at N-methyl-d-aspartate (NMDA) receptors and reduces neuronal injury after cerebral ischemia by blocking the excitotoxic effects of glutamate. However, cerebral regeneration by means of endogenous neurogenesis may be impaired with blockade of NMDA receptors. The effects of S(+) ketamine on post-ischemic neurogenesis are unknown and investigated in this study. Methods: Thirty-two male Sprague–Dawley rats were randomly assigned to the following treatment groups with intravenous S(+) ketamine anesthesia: S(+) ketamine 0.75 mg/kg/min with or without cerebral ischemia and S(+) ketamine 1.0 mg/kg/min with or without cerebral ischemia. Eight non…