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At least 667 records · Page 37Linked to original sources
PubMed2000

Increased expression of mRNA encoding ferritin heavy chain in brain structures of a rat model of absence epilepsy.

Differential mRNA display was carried out to find genes that are differentially regulated in the brain of a rat strain with absence epilepsy, the genetic absence epilepsy rats from Strasbourg (GAERS). Among the 32 differentially displayed cDNA fragments actually cloned and sequenced, one shows 100% identity with the rat heavy chain ferritin (H-ferritin) mRNA. Northern blot analysis confirmed the up-regulation of the H-ferritin mRNA. Using dot blotting, a 40% increase in expression was reported in the subcortical forebrain of the adult GAERS, while cortex, brain stem, and cerebellum appeared unmodified. This change was not observed in the brain of 25-day-old rats, an age at which the epileptic phenotype is not present. By in situ hybridization, the enhanced expression was localized in the hippocampus. The increase in mRNA encoding H-ferritin was not immunodetected at the protein level by Western blotting. These results are not apparently related to the neural substrate of SWD or to the distribution of local increase in glucose metabolism previously described in the GAERS. It is hypothesized that the up-regulation of the H-ferritin mRNA is part of a mechanism protecting the hippocampus, a seizure-prone area, against a possible overactivation during absence seizures.

Age Factors↗
PubMed1990

Brain structures important for solving a sawdust-digging problem in the rat.

Young rats subjected to bilateral lesions to one of 37 different brain sites were initially trained to traverse a narrow runway to reach a goal box containing water. The test involved blocking a portion of the runway with sawdust and determining whether the animals would burrow through the sawdust to gain access to the goal box. Lesions to 30 brain sites produced deficient performance on the sawdust-digging problem. This study, combined with earlier investigation of 11 additional brain sites, shows that 41 of 48 total brain sites are involved in this task. These findings suggest that underlying brain mechanisms include a nonspecific mechanism and several specific mechanisms, such as visuospatial-attentional, visual discrimination, vestibular-proprioceptive-kinesthetic discrimination, response flexibility, but much less place learning mechanisms.

Animals↗
PubMed2004

Estrogen- and tamoxifen-associated effects on brain structure and function.

We evaluated the effects of estrogen and tamoxifen, a selective estrogen receptor modulator, on positron emission tomography (PET) measures of brain glucose metabolism and magnetic resonance imaging (MRI) measures of hippocampal atrophy. Three groups of postmenopausal women were studied, women taking estrogen (ERT+), women with breast cancer taking tamoxifen (TAM), and women not taking estrogen or tamoxifen (ERT-). All subjects received a PET scan, an MRI scan, and cognitive testing. The TAM group showed widespread areas of hypometabolism in the inferior and dorsal lateral frontal lobes relative to the other two groups. The ERT- group showed lower metabolism in the inferior frontal cortex and temporal cortex with respect to the ERT+ group. The TAM group also showed significantly lower semantic memory scores than the other two groups. Finally, the TAM group had smaller right hippocampal volumes than the ERT+ group, an effect that was of borderline significance. Both right and left hippocampal volumes were significantly smaller than the ERT+ group when a single outlier was removed. The ERT- group had hippocampal volumes that were intermediate to the other two groups. These findings provide physiological and anatomical evidence for neuroprotective effects of estrogen.

Aged↗
PubMed2005

Calbindin distribution in cortical and subcortical brain structures of normal and rabies-infected mice.

Rabies has been an enigmatic disease of the nervous system because microscopic findings in the brain tissue are not paralleled by the severity of the clinical illness. The calcium binding protein calbindin (CB) is a neuronal marker of great interest in neuroanatomy and neuropathology. CB-ir neurons in the striatum and cerebral cortex are gabaergic cells. In the present work CB-immunoreactivity was evaluated in brains of normal and rabies-infected mice. Rabies infection caused loss of CB-immunostaining in the cortical supragranular layers as well as in the striatum. Loss of CB in the brains of mice infected with rabies virus can produce impairment in Ca++ homeostasis and in the gabaergic neurotransmission.

Animals↗
PubMed1977

[Use of disulfiram in a histochemical study of the influence of different stimuli on the concentration of noradrenaline in brain structures].

With the help of the histochemical fluorescence method the changes in noradrenaline fluorescence of nuc. septi lateralis, nuc. interstitialis striae terminalis and nuc. preoticus medialis during conditioning and unconditioned stimulation were studied. In 135 disulfiram pretreated rats the depletion of noradrenaline fluorescence in the investigated structures was found after electro-stimulation of feet during 5 min., 1 and 2 hours, open-field behavior and reproduction of a conditioned avoidance response. Twelve hours after disulphiram administration the suppression of the open-field behavior and reproduction of the conditioned avoidance response as well as the depletion of noradrenaline fluorescence in the investigated structures were detected.

Animals↗
PubMed2003

Retrograde amnesia and the volume of critical brain structures.

There are many controversies concerning the structural basis of retrograde amnesia (RA). One view is that memories are held briefly within a medial temporal store ("hippocampal complex") before being "consolidated" or reorganised within temporal neocortex and/or networks more widely distributed within the cerebral cortex. An alternative view is that the medial temporal lobes are always involved in the storage and retrieval (reactivation) of autobiographical memories (multiple trace theory). The present study used quantitative magnetic resonance imaging (MRI) in 40 patients with focal pathology/volume loss in different sites, to examine the correlates of impairment on three different measures of RA. The findings supported the view that widespread neural networks are involved in the storage and retrieval of autobiographical and other remote memories. Brain volume measures in critical structures could account for 60% of variance on autobiographical memory measures (for incidents and facts) in diencephalic patients and for 60-68% of variance in patients with frontal lesions. Significant correlations with medial temporal lobe volume were found only in the diencephalic group, in whom they were thought to reflect thalamic changes, but not in patients with herpes encephalitis or hypoxia in whom the temporal lobes were particularly implicated. The latter finding fails to support one of the main predictions of multiple trace theory, as presently expounded.

Amnesia, Retrograde↗
PubMed2004

Dichotic listening in children with focal epilepsy: effects of structural brain abnormality and seizure characteristics.

The study examined performance on a dichotic listening test in children with focal epilepsy. The aim of the study was to explore how factors related to brain pathology would affect ear advantage. The effects of lateralization of epileptogenic area, size and localization of structural abnormality on MRI findings, and seizure characteristics were studied. Children treated for focal epileptic seizures took part in the study (N = 35). The dichotic test consisted of pairs of words, nonwords, syllables and vowels. Results demonstrated that large congenital structural abnormality in the left hemisphere altered ear advantage whereas smaller abnormality and right-hemisphere abnormality did not. Further, epileptic seizures of left-hemisphere origin that had started at an early age affected ear advantage whereas seizure frequency at the time of the assessment did not. Children with early onset of seizures of right-hemisphere origin had a strong right-ear advantage. The total score did not differ between the groups. There was a strong negative correlation between the scores for the right-ear and the left-ear. The findings were interpreted to indicate altered functional dominance for perception of auditory, linguistic stimuli following early left-hemisphere pathology rather than unilateral functional suppression.

Adolescent↗
PubMed1988

Molecular cloning of two isoforms of the plasma membrane Ca2+-transporting ATPase from rat brain. Structural and functional domains exhibit similarity to Na+,K+- and other cation transport ATPases.

Complementary DNAs for two isoforms of the plasma membrane Ca2+-ATPase from rat brain have been isolated. The cDNAs were identified using an oligonucleotide probe derived from a conserved amino acid sequence of the ATP binding site of the aspartylphosphate family of transport ATPases. The complete nucleotide sequences have been determined, and the primary structures for both isoforms have been deduced. The Mr of isoform 1, which has 1,176 amino acids, is 129,500 and that of isoform 2, which has 1,198 amino acids, is 132,605. A region of isoform 1 exhibits perfect amino acid identity with a fragment consisting of 17 amino acids from the phosphorylation domain of the human erythrocyte calmodulin-sensitive Ca2+-ATPase (James, P., Zvaritch, E.I., Shakhparonov, M.I., Penniston, J.T., and Carafoli, E. (1987) Biochem. Biophys. Res. Commun. 149, 7-12). A comparison of transport ATPases from diverse species has allowed the identification of a sequence that may form part of a second ATP binding site. Amino acid similarity and hydropathy profile comparisons suggest that the transmembrane organization of the plasma membrane Ca2+-ATPase is the same as that of the Na+,K+-ATPase and sarcoplasmic reticulum Ca2+-ATPase; the data indicate that each of these enzymes has an even number of transmembrane domains and that their C termini are located on the cytoplasmic side of the membrane. An arginine-rich sequence that is highly characteristic of the "A" domain of a calmodulin binding site is located near the C termini of both isoforms. This putative A domain is identical in isoforms 1 and 2 but their "B" domains, and the remaining C-terminal sequences, are very different. However, 3'-untranslated sequences of the isoform 1 transcript have the potential to encode a calmodulin binding B domain and a C terminus that is very similar to that of isoform 2. This suggests the possibility that additional diversity may occur via alternative processing of the primary transcript.

Adenosine Triphosphatases↗
PubMed1992

Novel isoforms of CaBP 33/37 (annexin V) from mammalian brain: structural and phosphorylation differences that suggest distinct biological roles.

Two calcium-dependent phospholipid- and membrane-binding proteins have been purified from bovine brain. These are termed CaBP33 and CaBP37. Complete sequence analysis has revealed that these two proteins are isoforms of annexin V. Despite an apparent difference of 4 kDa between the two proteins on SDS-PAGE, only two amino-acid substitutions were found. These are, in CaBP33, Ser-36 and Lys-125 and in CaBP37, Thr-36 and Glu-125. This corresponds to a mass difference of 15 Da. This was confirmed by electrospray mass spectrometric analysis. Both isoforms can be phosphorylated substoichiometrically in vitro by protein kinase C at residue Thr-22.

Amino Acid Sequence↗
PubMed1984

Uptake and subcellular distribution of 65zinc in brain structures during the postnatal development of the rat.

The uptake ratio of 65zinc into the postnatally developing hippocampal formation, cerebellum and remainder of the brain showed only minor differences, whilst following subcellular fractionation a marked decrease in 65zinc uptake from postnatal day 15 to adulthood was found in nuclear sediments (hippocampal formation 44.3%, cerebellum 27.5%), along with an increase in synaptosomal fractions on the hippocampal formation by 55.4% and of the cerebellum by 37.1%. The shift of zinc out of the perikarya into terminal fields during the postnatal development without substantial alterations of the net zinc content is supposed to be a consequence of a functional relation of zinc to synaptic transmission processes.

Age Factors↗
PubMedDate not supplied

Double pituitary glands with partial duplication of facial and fore brain structures with hydrocephalus.

A female term infant was born with multiple bony and facial abnormalities involving the mandible, palate, tongue, nasopharynx, vertebrae, ribs and brain. Death occurred at 1 week and a rare combination of forebrain anomalies, were found in a big head, with complete agenesis of the corpus callosum with duplication of the infundibulum, pituitary, anterior third ventricle and aqueduct. The CAT scan was diagnostic of agenesis of corpus callosum. Incomplete twinning or incompetent neural induction with genetic and epigenetic factors have been suggested as possible mechanisms responsible for this rare malformation.

Abnormalities, Multiple↗