bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of gangliosides by cultured oligodendrocytes
Authors: Mack Stephen R. , Szuchet Sara , Dawson Glyn 
Published: January 2005

AbstractGangliosides are enriched in the nervous system compared to other tissues. The synthesis of gangliosides by monolayer cultures of isolated oligodendrocytes has not previously been investigated. Cells were labeled with [3H]galactose at preselected times and gangliosides isolated by phase partition, purified, and identified by chromatography. Cultured oligodendrocytes showed selectivity in their synthesis of gangliosides, which was expressed in the type of ganglioside synthesized as well as in the change of incorporation over time in culture. For the first ten days, there was very little incorporation of [3H]galactose in gangliosides, but this was followed by a stimulation of uptake for GM3, GM1/GD3, and GD1 gangliosides, reaching a maximum after approximately 25–30 days in vitro. There was little incorporation into GM2 or trisialogangliosides throughout the life of the cultures. Since oligodendrocytes synthesize extensive membranes during this period, one may speculate that the de novo‐synthesized gangliosides are used for membranes.
Effect of hypoxia on the incorporation of [2‐3H]glycerol and [1‐14C]‐palmitate into lipids of various brain regions
Authors: Alberghina M. , Giuffrida A. M. 
Published: January 2005

AbstractThe lipid metabolism in guinea pig brain after intermittent hypoxia, prolonged for 80 hrs, was markedly impaired. The in vivo incorporation of [2‐3H]glycerol and [1‐14C]palmitate into lipids of microsomes, mitochondria, myelin, and synaptosomes, purified from cerebral hemispheres, was significantly lower in the hypoxic animals than in the controls. The same effect was observed on the incorporation of labeled precursors into lipids of mitochondria purified from cerebellum and brainstem. In particular, the labeling of the major phospholipids present – ie, phosphatidylcholine (PC) and phosphatidylethanolamine (PE) – in the mitochondria of the three brain regions examined decreased after hypoxic treatment.
Effect of taurine on seizures induced by 4‐aminopyridine
Authors: Pasantes‐Morales H. , Arzate M. E. 
Published: January 2005

AbstractThe effect of intraperitoneally injected taurine against the convulsive activity induced by 4‐aminopyridine (4‐AP) was studied in 12‐ to 15‐day‐old mice. At a dose of 2.6 mg/kg, taurine increased the latency of clonic seizures from 7 to 20 minutes, reduced the incidence of tonic seizures from 92% to 30% and the postconvulsive mortality from 80% to 31%. The injection of EDTA prior to the administration of taurine prevented the protective effect of the amino acid. GABA and glycine at the same doses did not protect against 4‐AP‐induced seizures. 4‐AP caused a small increase (19%) in 45Ca accumulation by mice brain synaptosomes incubated in a Krebs‐HEPES medium containing low CaCl2 (0.1 mM) and also slightly potentiated the veratrine and potassium‐induced increase in calcium accumulation. 4‐AP at concentrations of 1–2 mM caused a marked increase (100%–500%) of 45Ca acculation by synaptosomes incubated in a Krebs‐bicarbonate medium containing 2.5 mM CaCl2. This increase was completely antagonized by taurine but not by GABA or glycine. The present observations suggest that the anticonvulsant effect of taurine might be mediated by 4‐AP‐calcium‐taurine interactions.
Taurine binding to membranes from rat brain regions
Authors: Löpez‐Colomé A. M. , Pasantes‐Morales H. 
Published: January 2005

Abstract[3H]‐taurine binding to membranes from different regions from rat brain was studied. Binding to membranes from cerebral cortex and its subcellular fractions, hypothalamus, olfactory bulb and cerebellum was measured. Binding to membranes from dorsal root ganglion was also determined. Na+‐dependent taurine binding was consistently observed in all the membranes except those from dorsal root ganglion. A KD = 4.06 μM was obtained for binding to membranes from cerebral cortex. Na+‐dependent taurine binding was displaced by 20 μM strychnine or bicuculline. Na+‐independent taurine binding with properties corresponding to a postsynaptic interaction could not be detected in any of the regions studied. The possibility of Na+‐dependent taurine binding, representing binding to uptake sites or to postsynaptic receptors for GABA and glycine, is discussed.
3H‐muscimol binding in synaptosomal fractions from bovine and developing rabbit retinas
Authors: Redburn Dianna A. , Mitchell Cheryl K. 
Published: January 2005

AbstractBovine and rabbit retina synaptosomal fractions bind the potent and specific GABA agonist, [3H]‐muscimol with high affinity and limited capacity. The high degree of pharmacological specificity and the subcellular distribution of these binidng sites are similar to those reported for [3H]‐GABA binding sites. These observations suggest that these sites represent the recongition sites for GABA receptors. The specific binding of [3H]‐muscimol in retinal homogenates from different aged rabbits reveal a distinct developmental profile with a fivefold to six fold increase in binding between days 5 and 13. Thus, it appears that GABA receptor development continues after eye opening in rabbits (day 9–10) and that receptor maturation is delayed by at least two to three days with respect to published reports of GABA uptake and evoked release.
Bouton renewal patterns in rat hindlimb cortex after thoracic dorsal funicular lesions
Authors: Ganchrow Donald , Bernstein Jerald J. 
Published: January 2005

AbstractThe transneuronal effect of bilateral, dorsal funicular lesions (T 12) on the frequency of boutons on cells in layer IV of hindlimb cortex was studies. Adult rats were utilized 1, 2, 3, 7, 14, 30, 45, 60, 90, or 120 days postoperative (DPO), and tissue was processed for the light microscopic visualization of silver‐impregnated boutons (Rasmussen method). Bouton counts were taken on soma, or along 5‐ and 10‐μm segments of proximal dendrite branching from soma. The soma diameter also was measured on those neurons chosen for bouton counts on the circumference of the soma. Statistically significant, increased afferentation on soma and proximal dendrite occurred during the first postlesion week relative to longer survival times; bouton counts on the proximal dendrite showed a trend (not statistically significant) toward increases above normal. These data mirror similar, consistent increases in bouton counts reported in thalamic ventroposterolateral nucleus of these same cases. At 14 DPO, bouton counts on the soma decreased below normal (P<0.005) and, except at 60 DPO, remained so through 120 DPO (P<0.025). Bouton counts on the proximal dendrite also decreased below normal at 14 DPO (P<0.005), thereafter exhibiting either periodic (along 5‐7μm) or extended (along 10‐7mu;m) periods in significant decreases from normal. Correlations in lesioned cases between the number of boutons on the soma and either bouton counts on proximal dendrite or soma diameter were positive and statistically significant (P<0.005 in all correlations). Possible anterograde (via the dorsal column‐medial lemniscal system) and/or retrograde (via the corticospinal tract) transneuronal mediation of these effects in hindlimb cortex is discussed.
On the presence of met 5‐enkephalin receptors on the plasma membrane of deiters'neurons and their modulation of GABA transport
Authors: Cupello Aroldo , Hydén Holger 
Published: January 2005

AbstractMet 5‐enkephalin blocks the active transport of GABA across plasma membranes of rabbit Deiters' neurons prepared by microdissection. Such an effect is receptor‐mediated, being reversed by the antagonist Naloxone.This result shows that Deiters' neurons bear enkephalin receptors, and suggests a hypothesis on the mechanism of enkephalin‐mediated neuronal inhibition.
Flow of glucose carbon into cholesterol and phospholipids in various regions of the adult rat brain: Enhanced incorporation into hypothalamic phospholipids
Authors: Barkai Amiram I. 
Published: January 2005

AbstractThe contribution of glucose carbon to the biosynthesis of cholesterol and phospholipids in distinct brain regions was studied quantitatively in the adult male rat. Rates of flow of glucose carbon into the lipids in vivo were calculated from two measurements: the curve representing the decrease in plasma 14C‐glucose with time and the specific activity of the cerebral lipid 180 minutes after a rapid intravenous injection of a tracer dose of D–U 14C‐glucose. The following brain regions were studied: cerebral cortex, hypothalamus, medulla, and corpus callosum and cerebellum. The values for carbon flow into phospholipids were significantly higher in the hypothalamus than in the whole brain, whereas small, but insignificant, regional differences were found for carbon flow into cholesterol. The conversion of U‐14C‐glucose to individual phospholipids of both hypothalamus and cerebral cortex was further investigated in vitro in order to establish whether the higher rate of carbon flow into hypothalamic phospholipids resulted from enhanced synthesis of a particular phospholipid. In agreement with the results obtained in vivo, the rate of incorporation of 14C into total phospholipids was 60% higher in hypothalamic tissue. The results indicate that the higher rate of carbon flow into hypothalamic phospholipids might be attributed to enhanced incorporation of glucose carbon to phosphatidyl‐choline and phosphatidyl‐ethanolamine following a faster conversion of glucose to glycerol in this brain region.
Influence of triiodothyronine on the amino acid uptake of brain and spinal cord in normal and spinal hemisected adult rats
Authors: Wells Michael R. , Lofton S. A. , Bernstein Jerald J. 
Published: January 2005

AbstractThe thyroid hormones triiodothyronine (T3) and L‐thyroxine appear to enhance regeneration in the peripheral and central nervous system (CNS). The following experiments examine possible metabolic substrates for the action of T3 on the adult rat CNS after spinal hemisection. The protein incorporation of (3H)lysine after a left spinal hemisection (T2) or control operations was examined 1, 3, 7, and 14 days postoperation. Triiodothyronine (1 μg/kg body weight in a bicarbonate buffer) was injected daily for the postoperation or equivalent time period. One hour prior to decapitation, animals were given a subcutaneous injection of 200 μCi of (3H)lysine. Samples of brain and spinal cord were dissolved, and the radioactivity of acid‐precipitable protein and acid‐soluble fractions were determined by scintillation counting. T3 treatment influenced the general levels of incorporation of all treated groups over all days postoperation. Specific effects were observed in spinal hemisected T3‐treated animals. A significant hemispheric (P<0.05) asymmetry was present at 3 days postoperation with the right somatomotor cortex higher in protein radioactivity than the left. In spinal cord, the area of the lesion and areas just caudal to the lesion were higher in (3H)lysine incorporation in T3‐treated rats relative to controls. T3 effects appear to involve an increased sensitivity of the cells of the injured nervous system to the hormone.
α1 and α2 Adrenergic receptors in mouse brain astrocytes from primary cultures
Authors: Ebersolt C. , Perez M. , Bockaert J. 
Published: January 2005

AbstractMouse brain astrocytes from primary cultures were found to contain both α1 and α2 adrenergic receptors. 3H WB 4101 labeled one category of binding site (KD=1.5±0.39 nM, Bmax =64±7.9 fmoles/mg protein) with typical α1 adrenergic specificity (WB 4101 >prazosin>yohimbine). The density of α1 adrenergic receptors was 2–3 times higher in mouse cerebral cortex than in glial cells.Like rat brain [U'Pritchard et al, 1979; Rouot et al, 1980], mouse glial cells were found to contain two categories of 3H clonidine binding sites: high affinity sites, which were identical to the high but not to the low affinity sites found in rat brain, since (1) they displayed the same affinity for 3H clonidine (KD=1.2±0.13 nM, n=4) and the same typical α2 adrenergic specificity (yohimbine>WB 4101 > prazosin); (2) the dissociation rate constant for clonidine binding was equal to 0.06 min−1, a value close to that found previously for the high affinity 3H clonidine binding sites in rat brain (0.05 min−1); and (3) divalent cations augmented and guanyl nucleotides reduced 3H clonidine binding as in rat brain. Na+ decreased 3H clonidine binding in a complex manner.The number of high affinity sites in glial cells (52 ±9.4 fmoles/mg protein, n=4) was half the number found in mouse cerebral cortex (98 fmoles/mg protein). Low affinity 3H clonidine binding sites (KD=81±18 nM, Bmax=96±5.8 fmoles/mg protein, n=3) were not fully characterized.In conclusion, glial cells contained the same α adrenergic receptors as those described in brain, but their physiological function is not yet known.
The vimentin‐GFA protein transition in rat neuroglia cytoskeleton occurs at the time of myelination
Authors: Dahl Doris 
Published: January 2005

AbstractExtraction with Triton, a nonionic detergent, is a common procedure to prepare intermediate filament enriched fractions from cells maintained in culture. The Triton‐Insoluble fraction is called a cytoskeletal preparation. Using this procedure, we previously demonstrated that vimentin and glial fibrillary acidic protein (GFA) are major cytoskeletal proteins of neuroglia, in newborn and adult rat brain, respectively. In the present communication we report that the vimentin‐GFA transition in rat brain occurs during the 2nd‐3rd week, ie, at the time of rapid myelination when dividing glioblasts in white matter differentiate into oligodendroglia and interfascicular astrocytes.
Reversible dissociation of a bovine cardiac factor that supports survival of avian ciliary ganglionic neurones
Authors: Bonyhady Rae E. , Hendry Ian A. , Hill Caryl E. 
Published: January 2005

AbstractThe relationships has been sttudied between a high and a low molecular weight form of a bovine cardiac factor that supports the survival of avian ciliary ganglionic neurones in culture. Reversible dissociation of the high molecular weight from into identical or similarly sized subunits of apparent molecular weight in the range 15,000–30,000 has been demonstrated. In addition, other inactive high molecular weight components of cardiac extract were found to interact synergistically with both active forms of the factor.
Changes in enzyme activities of glycerolipid metabolism of guinea‐pig cerebral hemispheres during experimental hypoxia
Authors: Alberghina Mario , Viola M. , Giuffrida A. M. 
Published: January 2005

AbstractHypoxic treatment causes changes of some enzymatic activities involved in the glycerolipid metabolism in subcellular fractions of guinea pig cerebral hemispheres. The activity of lysophosphatidylcholine acyltransferase, choline phosphotransferase, glycerol‐3‐phosphate acyltransferase(s), as well as the activity of triacylglycerol lipase significantly decreased in the microsomes of cerebral hemispheres of animals intermittently exposed to hypoxic treatment for eighty hours. At the same time, a marked activation of microsomal and mitochondrial phospholipase A2 occurred. The changes of the above‐mentioned enzymatic activities after the hypoxic treatment correlated well with the increase in the level of brain and blood free fatty acids. The changes also correlated with the decrease of labeled lipid precursors incorporated into lipids of the cerebral hemispheres, observed during oxygen insufficiency.
Excitatory and inhibitory effects of acetylcholine on the anterior aorta muscle of Aplysia
Authors: Sawada M. , Hara N. , Ichinose M. , Maeno T. 
Published: January 2005

AbstractThe acetylcholine (ACh) responses of anterior aorta muscle cells of Aplysia kurodai were studied by intracellular recording and ACh iontophoresis. Three different types of membrane potential change were observed in response to ACh pulses: a rapid Na+‐mediated depolarizing response, a slow, mainly Cl−, in part K+‐mediated, hyperpolarizing response, and Na+ (for depolarizing component) and Cl− (for hyperpolarizing component)‐mediated biphasic response. The depolarizing response and the depolarizing component of the biphasic response were effectively blocked by hexamethonium or atropine. The hyperpolarizing response and the hyperpolarizing component of the biphasic response were completely blocked by tubocurarine. Low concentrations of ACh inhibited and relaxed the anterior aorta muscle; high concentrations of ACh excited the muscle and initiated contraction. The biphasic responses to ACh are likely due to the presence of more than one ACh receptor type on the same cell membrane of the anterior aorta muscle fiber.
Differential effects of early undernutrition in white and grey matter regions of rat brain
Authors: Rao K. V. Subba , Rao K. Subba 
Published: January 2005

AbstractThe effect of early postnatal undernutrition and subsequent rehabilitation on wet weight, DNA, RNA, protein, and the activities of acid and alkaline DNases in white and grey matter region of rat brain was studied. In respect to the various parameters studied, white matter was found to be markedly vulnerable to undernutrition, but the grey matter region was unaffected. It has also been observed that the earlier the initiation of nutritional rehabilitation (10th postnatal day) the better was the recovery of the white matter to a normal condition, and in some cases early nutritional rehabilitation resulted in better than normal biochemical composition of the region. The specific activity of acid DNase was unaffected by weanling undernutrition in both white and grey matter. The total activity of this enzyme, which was significantly reduced in white matter of undernourished animals, exhibited a remarkable recovery following rehabilitation, to more than normal levels at 150 days of age. Total activity of alkaline DNase was reduced only in 15‐day‐old white matter of deprived animals, and here also rehabilitation brought back this enzyme to significantly more than normal levels. It is concluded that the two DNases, whatever their actual physiological role might be, are synthesized in a preferential manner during the rehabilitation.
β‐Adrenergic receptor binding in different regions of rat brain after various intensities of electroshock: Relationship to postictal EEG
Authors: Perumal Authur S. , Barki Amiram I. 
Published: January 2005

AbstractRelationships among different intensities of electroshock treatment (EST), EEG‐recordable primary after discharge (PAD), and β‐adrenergic binding in various brain regions were investigated in adult rats. Different intensities of EST (1–2, 6–8, 20–30 mamp) were applied through ear‐clip electrodes for 7 consecutive days. A Sigmoidal relationship was observed between the PAD and the applied currentintensity. 3H‐dihydroalprenolol (DHA) was used as a ligand to evaluate β‐adrenergic receptor binding in membrane preparation of the following brain regions: Cerebral cortex, cerebellum, pons‐medulla, and “midregion”–which consisted of the remainder tissue including thalamus, striatum, and midbrain. A significant decrease (28%) in binding was observed in cortex tissue after EST of 6–8 mamp but no changes were observed after either 1–2 mamp or 20–30 mamp. In “midregion,” a significant increase (40%) in binding was observed after EST with the subconvulsive intensity (1–2 mamp) whereas no changes were seen at higher intensites. The results suggest that in cortex, the function relating β‐adrenergic binding to current intensities may not be monotonic. The increase in binding seen in the “midregion” after subconvulsive EST may not be associated with changes related to the clinical efficacy of EST.
Toxic effects of ouabain and food and cosmetic dyes on nerve growth factor‐promoted differentiation of neurites in culture
Authors: Morris Stephen J. , Chronwall Bibie M. 
Published: January 2005

AbstractThe toxic effects of ouabain and various fluorescein analogs have been tested on nerve growth factor‐promoted (NGF‐promoted) outgrowth of neurites from embryonic chick sensory ganglia embedded in a matrix of native collagen. Ouabain inhibits outgrowth with an IC50 of approximately 5 μM. Erythrosin B (USFD&C Red 3) and other fluorescein derivative dyes brominated or iodinated on the xanthene ring also inhibit neurite outgrowth with IC50'S as low as 10 μm and promote early retraction of growing neurites. The effects of the dyes are due, at least in part, to photooxidation of the NGF, but they may also act directly on the cells. The culture system should prove useful as both a general and a specific in vitro assay for neurotoxicity.
Studies on metabolism of branched chain amino acids in brain and other tissues of rat with special reference to leucine
Authors: Rao T. Indira , Rao G. N. , Swamy M. , Sadasivudu B. 
Published: January 2005

AbstractLeucine aminotransferase (EC 2.6.1.6) and 2‐oxoisocaproate dehydrogenase (EC 1.2.4.3) were studied in rat cerebral cortex, cerebellum, brain stem, liver, and muscle in normal and animals starved for 48 hours. In the brain, leucine aminotransferase, valine aminotransferase, and 2‐oxoisocaproate dehydrogenase showed a significant increase in starvation only in cerebellum while there was increase in 2‐oxoisocaproate dehydrogenase in cerebral cortex only. A significantly high increase in the activity of 2‐oxoisocaproate dehydrogenase was observed in muscle in starvation. A significant decrease in the activity of leucine aminotransferase was observed in liver in starvation. The increase in the activity of 2‐oxoisocaproate dehydrogenase in muscle and a decrease in the activity of leucine aminotransferase in liver in starvation indicate that the leucine is predominantly metabolized in extra hepatic tissues particularly in muscle.As a result of intraperitoneal administration of 2 ml of leucine (5 mM), a significant increase in 2‐oxoisocaproate dehydrogenase occurred in cerebral cortex, liver, and muscle while a profound increase in the activity of glutamate dehydrogenase (EC 1.4.1.2) was observed in all the brain regions and liver under these conditions. A significant increase in the content of glutamic acid, alanine, and GABA was observed in all the three regions of the brain after the administration of leucine. A significant increase in the content of glutamine was observed only in the cerebellum and cerebral cortex after leucine administration. These results indicate that leucine in brain might contribute to the formation of glutamate, not only by transmination, but also by promoting glutamate dehydrogenase activity. Thus, there is a change in the metabolism of glutamate family of amino acids and energy depletion. These results are discussed in relation to the brain function.