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At least 811 records · Page 45Linked to original sources
PubMed2004

Ontogenetic profile of glutamate uptake in brain structures slices from rats: sensitivity to guanosine.

The excitotoxicity of the neurotransmitter glutamate has been shown to be connected with many acute and chronic diseases of the CNS. High affinity sodium-dependent glutamate transporters play a key role in maintaining adequate levels of extracellular glutamate. In the present study, we used slices of striatum, hippocampus and cortex from rat brain to describe the in vitro profile of glutamate uptake during development and ageing, and its sensitivity to guanosine. In all structures, glutamate uptake was higher in immature animals. There was a maximum decrease in glutamate uptake in striatum and hippocampus in 15-month-old rats, which later increased, while in cortex there was a significant decrease in rats aged 60 days old. The effect of guanosine seems to be age and structure dependent since the increase in basal glutamate uptake was only seen in slices of cortex from 10-day-old animals.

Aging↗
PubMed1988

Superimposition of an average three-dimensional pattern of brain structures on CT scans.

A method is described for the superimposition of an averaged telencephalic anatomical model and individual CT scans. The model is digitally available and derived from 3-D measurements of 30 post-mortem brains. It is averaged in size in relation to the midintercommissural point. The midintercommissural point in the individual brain is gained from reformed parasagittal projection images. The model is adjusted to the individual CT scan series by scaling and rotating according to the best fit and correspondence of the position of the central sulcus. The method needs no invasive neuroradiological techniques but is based on current computer algorithms.

Brain↗
PubMedDate not supplied

Sex differences in brain structure in geriatric depression.

OBJECTIVE: In an exploratory study, authors compared patients with late-life major depression (MDD) and age-matched control subjects to examine sex differences in frontal and orbito-frontal (OFC) regional brain volumes. METHODS: The study sample comprised 41 patients with MDD and 41 controls. Subjects underwent comprehensive neuropsychiatric examinations and magnetic resonance imaging (MRI) scans. Corrected frontal and OFC gray-matter volumes were compared among men and women in both groups. RESULTS: The depression group had lower MMSE scores, greater severity of medical burden, apathy, psychomotor retardation, and poor health-related quality of life than the controls. Men in both groups had a greater severity of medical burden, apathy, and psychomotor retardation than women. The depression group had smaller OFC total and gray-matter volumes than the controls after matching for age. Men had smaller frontal-matter volumes than women in both groups. The diagnosis x sex interaction in brain regional volumes was observed only after controlling for medical burden. CONCLUSIONS: Sex differences in brain neuroanatomy may be important in the pathophysiology of geriatric depression. Men may be susceptible to atrophy in frontal subregions. Medical burden may contribute to the diagnosis x sex interaction in brain regional volumes.

Aged↗
PubMedDate not supplied

[Brain structural abnormalities of bipolar disorder].

The number of structural neuroimaging studies of bipolar disorder have increased during recent years, expanding the literature on the nature of cerebral abnormalities underlying this disorder. The purpose of this paper is to provide a selective review on the main issues concerning this literature. Consistent findings are higher rate of periventricular and deep subcortical white matter hyperintensites seen on MRI. Although there is strong evidence for links between hyper-intense lesions and age or cardio-vascular risk factors, some authors have observed the presence of these abnormalities early in the course of the illness. There are also frequent reports on ventricular enlargement, which has been described as mild and predominant in the right lateral ventricle. Total cerebral volume appears to be preserved. Whereas changes in total grey matter volume are uncertain, evidence suggests that reduced white matter volume reflects genetic factors predisposing to the disorder. Recent studies have reported volume changes in several cortical areas including the subgenual cingular, frontal and temporal cortices. Additionally, a number of reports described morphometric abnormalities in various subcortical structures, such as amygdala, basal ganglia and thalamus. Part of the variability in the morphometric abnormalities might be attributable to differences in clinical status and demographic characteristics of patient groups. Despite some inconsistencies across the studies, it emerges that abnormalities are asymmetrically distributed throughout the two cerebral hemispheres. When increase in volume is reported, it is preferentially localised in the left cerebral hemi-sphere and more specifically in prefrontal and temporal cortices and in amygdala. By contrast, when structural abnormalities concern the right cerebral hemisphere, they are identified as deficits. These latter results are in direct line with those of studies of mania following brain injuries, which report that these secondary mania result mainly from right cerebral lesions. It is also important to notice that most of the abnormalities concern both the cortical and subcortical level, ie frontal, striatal, thalamic and limbic regions. These abnormalities highlight the role in the pathophysiology of bipolar disorder of the loops involved in emotional information processing. The particular role of fronto-limbic loops in the phenomenology of bipolar disorder have been emphasised by recent data from functional neuroimaging studies.

Amygdala↗
PubMed1989

Limbic brain structures are important sites of kappa-opioid receptor-mediated actions in the rat: a [14C]-2-deoxyglucose study.

The [1-14C]-2-deoxyglucose technique was employed to evaluate the regional pattern of alterations in glucose utilization in the rat brain, pituitary and spinal cord induced by the selective kappa-opioid agonist U-50,488H (trans-3,4-dichloro-N-methyl-N[2-(1-pyrolidinyl) cyclohexyl]-benzeneacetamide). Within the dose range used (0.5-5 mg/kg), U-50,488H produced a dose-dependent attenuation of nociceptive thresholds and a place aversion in the place conditioning test, allowing for a correlation of the regional pattern of changes in glucose utilization with certain behavioral responses. The regional changes in glucose utilization induced by U-50,488H in the brain were most pronounced in components of the limbic forebrain circuit such as the anterior thalamic nuclei, mammillary body, frontal cortex, lateral septal nucleus, nucleus accumbens and lateral habenular nucleus as well as in the brainstem tegmental nuclei and the dorsal and median raphe nucleus (components of the limbic midbrain area). Glucose utilization was decreased in the frontal cortex and increased in the other regions. An increase in glucose utilization also was observed in the central gray pons. Increases in glucose utilization in the pituitary were restricted to the intermediate lobe. In the lumbar part of the spinal cord, glucose metabolism was enhanced in the region around the central canal and in the ventral horn. The changes in glucose metabolism observed in these structures suggest that the aversive (dysphoric) effects of U-50,488H may be due to the altered activity of the limbic structures of the forebrain and midbrain which have been implicated in emotional and affective processes. The increased activity in the intermediate lobe of the pituitary, furthermore, might reflect a stress component in the effects of this drug. Since the dorsal raphe nucleus and the region of the central gray pons have been implicated in both analgesia and pain processes a supraspinal site of antinociceptive action of U-50,488H, in addition to a spinal site of action, must be considered.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1980

Biosynthesis in vitro of mono- and di-sialosylgangliosides from gangliotetraosylceramide by cultured cell lines and young rat brain. Structure of the products, and activity and specificity of sialosyltransferase.

Incubations in vitro of GA1, labeled with 3H in the terminal D-galactopyranosyl group, with nonradioactive CMP-NeuNAc in the presence of homogenates of C21 rat brain glial cells, NIE mouse neuroblastoma cells, 3T3 mouse fibroblasts, SV 40-transformed 3T3 cells, chick embryo fibroblasts, Rous sarcoma virus-transformed chick embryo fibroblasts, and 9-day old rat brain resulted in all cases in the formation in high yield of GM1b, in which the neuraminidase-labile NeuNAc group is linked at O-3 of the terminal D-galactosyl residue, as shown by permethylation studies. No trace of the naturally occurring neuraminidase-stable GM1a was detected in any case. In addition, with NIE cells, and normal and RSV-transformed chick embryo fibroblasts, a disialosylganglioside (GD1) differing from GD1a and GD1b, and bearing only one substituent at O-3 of the terminal D-galactopyranosyl residue was formed. It was also biosynthesized from GM1b and CMP-NeuNAc by NIE and chick embryo cells but not by C21 cells, or rat brain. However, C21 cells and rat brain were capable of synthesizing GD1a from GM1a. Periodate oxidation degraded both NeuNAc groups in GD1 to a 7-carbon fragm:nt, indicating lack of substitution at O-8. GM1b could not be detected as a natural product in rat brain.

Animals↗
PubMed1981

[Catecholamines in the brain structures of rats responding differently to the "open field" test].

Wistar rats divided into groups according to the open-field test showed essential differences in the catecholamine level in 3 out of eight principal catecholamine-synthesizing brain nuclei. In rats with a sharp decrease in crossing and rearing seen throughout the experiment, the adrenaline and dopamine levels in A1 area were significantly higher and the dopamine level in locus ceruleus and n. arcuatus was lower as compared with rats which were not so emotional. It is suggested that the open-field behavior of Wistar rats correlates with the brain catecholamine interplay, the main part being played by adrenaline-synthesizing neurons of A1 area, noradrenaline-synthesizing neurons of locus ceruleus and dopamine-synthesizing neurons of n. arcuatus.

Animals↗
PubMedDate not supplied

[Effect of chronic morphine administration on concentrations of individual lipids in various rat brain structures].

The effect of morphine administration (for 7 days in the increasing doses of 20 to 40 mg/kg body weight) and its withdrawal (following 1, 3 and 7 days) on the concentrations of lipid fractions in different rat brain regions have been studied. It was found that the drug injected decreased the levels of total lipids and cholesterol in the cortex of the hemispheres and increased cholesterol concentration in the cerebellum. One day after the withdrawal the brain stem showed a decreased amount of cholesterol, its concentration being increased in the cerebellum. Three days after the withdrawal the cerebellum and the hemisphere cortex demonstrated a reduced level of total lipids. Seven days after morphine withdrawal the level of total lipids was diminished in the brain stem, whereas the phospholipids concentration was elevated in the cortex.

Analgesics, Opioid↗
PubMed1994

Influence of short-lasting bilateral clamping of carotid arteries (BCCA) on GABA turnover in rat brain structures.

We have previously shown that short-lasting reduction of cerebral blood flow by bilateral clamping of carotid arteries (BCCA) results in long-lasting increase in regional GABA concentration and decrease in seizure susceptibility in rats. In the present experiments, the effect of BCCA on GABA turnover and the enzymes involved in GABA synthesis and degradation were studied in rats. Regional GABA turnover was measured by means of GABA accumulation induced by the GABA-transaminase (GABA-T) inhibitor aminooxyacetic acid (AOAA). Fourteen days after BCCA, GABA turnover was significantly increased in hippocampus, substantia nigra and cortex, but not different from sham-operated controls in several other brain regions, including striatum, hypothalamus and cerebellum. The activity of glutamate decarboxylase (GAD) measured ex vivo did not show any changes in investigated structures, while the activity of GABA-T was slightly increased in hippocampus. The increased GABA turnover in some brain regions may explain our previous findings of increased GABA content in these brain regions and decreased sensitivity of BCCA treated animals to the GABAA-receptor antagonist bicuculline.

4-Aminobutyrate Transaminase↗
PubMed2005

Structural brain changes in Parkinson disease with dementia: a voxel-based morphometry study.

BACKGROUND: Parkinson disease with dementia (PDD) results from neuropathological changes in cortical and subcortical brain regions. Voxel-based morphometric analysis of magnetic resonance images can contribute to in vivo identification of the cerebral regions predominantly involved in PDD. OBJECTIVE: To identify structural cerebral regions most closely related to the presence of PDD. DESIGN: Magnetic resonance images were obtained from 16 patients who had PDD, 13 patients with PD without dementia, and 13 age-matched healthy control subjects. Gray matter volumes were compared using optimized voxel-based morphometric analyses. RESULTS: Compared with healthy controls, patients with PDD showed gray matter volume decreases in several of the following regions: bilateral putamen, accumbens nuclei, left side of the thalamus, bilateral hippocampus, parahippocampal region, and anterior cingulate gyrus. Patients with PD also showed gray matter reductions compared with healthy controls in the right side of the hippocampus, left anterior cingulate gyrus, and left superior temporal gyrus. CONCLUSIONS: The hippocampus, thalamus, and anterior cingulate are the regions most affected in PDD. Our results agree with recent neuropathological findings suggesting the involvement of the limbic and cortical areas in PD.

Aged↗
PubMed2006

Intra-individual variability in behavior: links to brain structure, neurotransmission and neuronal activity.

Intra-individual variability reflects a transient, within-person change in behavioral performance. It is a common component of aging-related cognitive decline and the behavioral changes associated with neurodegenerative and other brain-related disorders such as traumatic brain injury and schizophrenia. Behavioral changes within an individual can reflect alterations at a systems or a cellular level in the brain, and monitoring intra-individual variability can therefore provide a warning of underlying pathology. Despite frequent reports of intra-individual variability, there is little synthesis, and no direct examination of the neural underpinnings. Here, we integrate seminal findings from cognitive research across lifespans of individuals, and also neuropsychological and neurobiological findings, to identify key questions and some potential answers, and to set challenges for fostering future research into intra-individual variability.

Aging↗
PubMed1990

Magnetic brain stimulation and immune response in the rat with lesioned brain structures.

Rats with electrolytic anterior hypothalamic lesions showed a suppressed Arthus reaction, delayed skin hypersensitivity, and antibody production at 7, 14 and 21 days after immunization with bovine serum albumin (BSA) in complete Freud's adjuvant (CFA). However, magnetic treatment of the brain of rats with anterior hypothalamic or caudate nucleus lesions increased both humoral and cellular sensitivity reactions. These data indicate that magnetic stimulation of the brain is capable of modulating immune functions.

Adjuvants, Immunologic↗
PubMed2003

Brain structures differ between musicians and non-musicians.

From an early age, musicians learn complex motor and auditory skills (e.g., the translation of visually perceived musical symbols into motor commands with simultaneous auditory monitoring of output), which they practice extensively from childhood throughout their entire careers. Using a voxel-by-voxel morphometric technique, we found gray matter volume differences in motor, auditory, and visual-spatial brain regions when comparing professional musicians (keyboard players) with a matched group of amateur musicians and non-musicians. Although some of these multiregional differences could be attributable to innate predisposition, we believe they may represent structural adaptations in response to long-term skill acquisition and the repetitive rehearsal of those skills. This hypothesis is supported by the strong association we found between structural differences, musician status, and practice intensity, as well as the wealth of supporting animal data showing structural changes in response to long-term motor training. However, only future experiments can determine the relative contribution of predisposition and practice.

Adolescent↗
PubMed1997

Differential distribution of synapsin IIa and IIb mRNAs in various brain structures and the effect of chronic morphine administration on the regional expression of these isoforms.

Quantitative reverse transcriptase-polymerase chain reaction and in situ hybridization techniques were used to determine the regional distribution of synapsin IIa and IIb mRNAs in rat central nervous system and to assess the effect of chronic morphine administration on the gene expression of these two isoforms of synapsin II. These isoforms are members of a family of neuron-specific phosphoproteins thought to be involved in the regulation of neurotransmitter release. Our data demonstrate the widespread distribution, yet regionally variable expression, of synapsin IIa and IIb mRNAs throughout the adult rat brain and spinal cord. The ratios of the relative abundance of synapsins IIa and IIb differed by up to 4.5-fold among the various regions studied. Synapsin IIa and IIb mRNAs were shown to be highly concentrated in the thalamus and in the hippocampus, whereas lower concentrations were found in most other central nervous system structures. In this study, we show differential regulation by morphine of synapsins IIa and IIb in various regions of the brain. In the striatum, a 2.4-fold increase was observed in the levels of synapsin IIa mRNA following chronic morphine regime, whereas no change was found for synapsin IIb. On the other hand, mRNA levels of synapsin IIb in spinal cord of chronically treated rats were markedly decreased (by 62%), while no alterations were observed in synapsin IIa. Selective regulation by morphine has also been demonstrated in several other central nervous system structures. The opiate-induced regulation of the gene expression of synapsin II isoforms could be viewed as one of the cellular adaptations to the persistent opiate effects and may be involved in the molecular mechanism underlying opiate tolerance and/or dependence.

Animals↗