bluuebunny/crossref_metadata_2025 huggingface dataset:
Maturation of thalamic inputs into the associative cortical areas during postnatal ontogenesis in cats
Authors: Tolchenova G. A. , Shikhgasanova I. Sh. , Batuev A. S.
Published: January 2005

Thalamic afferents into the sensorimotor and parietal cortex (area 7) were studied using the method of retrograde axonal transport of horseradish peroxidase (HRP) in kittens of three age groups. Following HRP injection into the sensorimotor cortex of 1‐ to 3‐day‐old kittens, labeled cells were found in the following nuclei: ventral posterolateral (VPL), ventral posteromedial (VPM), medialis dorsalis (MD), centrum medianum (CM), ventral posteromedial (VPM), medialis dorsalis (MD), centrum medianum (CM), and centralis lateralis (CL). In 9‐ to 10‐day‐old kittens the number of labeled cells and density of reaction product within the cells was found to increse markedly. In 21‐ to 30‐day‐old kittens, besides the above‐mentioned nuclei, labeled cells were also revealed in n. ventralis lateralis (VL). A similar trend was seen following HRP injections into area 7. In 1‐ to 3‐day‐old kittens, labeled cells were found in n. lateralis posterior (LP), in n. ventralis anterior (VA), and in Pulvinar (Pulv). Both in the 9‐to 10‐day‐old and the 21‐ to 30‐day‐old kittens, labeled cells were also demonstrated in n. lateralis dorsalis (LD) and CL. For both of the cortical areas the number of labeled cells and the density of labeling within the cells increase during postnatal ontogenesis. This may be attributed to the growing number of axon terminals. In general, our results suggest that differences in the thalamic connections of single cortical areas can be distinguished during the postnatal ontogenesis of the brain.
Rapid axonal transport of phosphatidylinositol in the rabbit optic pathway
Authors: Alberghina M. , Viola M. , Giuffrida A. M.
Published: January 2005

At different time intervals (4 hr up to 24 days) after intravitreal injection of myo‐(2‐3H)‐inositol, the specific activity (sp act) of phosphatidylinositol (PtdIns) and water‐soluble compounds extracted from the retina, optic nerve (ON), optic tract (OT), lateral geniculate body (LGB), and superior colliculus (SC) was measured. Furthermore, 2 days after biocular injection of the labeled precursor, the specific activity of PtdIns and other major phospholipids in the various subcellular fractions (myelin, axolemma, synaptosomes, mitochondria, and microsomes) purified from ON + OT, from LGB, and from SC was evaluated. In the ON and OT, the phospholipids were labeled 8 hr after the precursor injection; in the LGB and SC after 8–12 hr. In all the optic components examined, the lipid specific activity reached a maximum at day 6 and decreased slowly until day 24 after injection. In the ON + OT, the specific activity of PtdIns, isolated from various subcellular fractions, decreased as follows: myelin > axolemma; in the LGB and SC as follows: microsomes > synaptosomes > myelin > mitochondria. The radioactivity present in the retina and in the optic pathway was exclusively localized in the PtdIns during the whole time interval studied. Ten days after the precursor injection, a high portion of the radioactivity transported was detected in the water‐soluble pool, separated from the ON and OT, whereas no significant counts in the corresponding LGB and SC pool were found. The kinetics of PtdIns labeling, observed in the different optic components, indicated a rapid axonal transport of the phospholipid; besides, the presence of labeled PtdIns in the purified myelin suggested a transaxonal migration of the phospholipid and its free precursor.
Differential effects of morphine withdrawal on cerebral β1‐ and β2‐adrenergic receptors
Authors: Kuriyama Kinya , Muramatsu Makoto , Ohkuma Seitaro , Tamura Jun‐Ichi , Ping Zuo Ping
Published: January 2005

Effect of morphine dependence and its withdrawal on the 3H‐dihydroalprenolol (3H‐DHA) binding for βadrenergic receptors,β1 andβ2, was examined by a computerized analysis of biphasic Hofstee plots. The relative density ofβ1 andβ2 receptors in the rat cerebral cortex was found to be approximately 70% and 30%, respectively. In rats rendered dependent on morphine by a subcutaneous implantation of a morphine pellet, the 3H‐DHA binding toβ1 andβ2 receptors was not altered. During the stage of withdrawal induced by administration of naloxone, however, the 3H‐DHA binding to the cerebral particulate fractions was increased, and this increase was due to the increased binding sites inβ1 but not inβ2 receptor. On the other hand, the apparent affinities ofβ1 andβ2 receptors for atenolol and salbutamol, selective antagonists forβ1‐ andβ2‐adrenergic receptors, respectively, were not altered under these experimental conditions. These results suggest that an abrupt increase in cerebralβ1‐receptor binding sites occurs at morphine withdrawal, and the occurrence of such a supersensitivity in cerebralβ1 receptor may be involved in the exhibition and/or maintenance of the abstinence syndrome in morphine‐dependent subjects.
Do neuronal signals regulate potassium flow in glial cells? Evidence from an invertebrate central nervous system
Authors: Walz Wolfgang
Published: January 2005

Experiments were conducted with the aid of intracellular microelectrodes to study physiological properties of neuropile glial cells in the central nervous system of the medicinal leech. The results showed significant contributions of both K+ and Cl− ions to the membrane potential. The transmitter substance 5‐hydroxytryptamine increased the K+ conductance of the cell membrane. On the basis of these experiments, a model for potassium homeostasis in leech neuropile is suggested, according to which excess K+ ions in the extracellular space lead to passive KCl fluxes across the glial cell membrane and the transmitter 5‐hydroxytryptamine induces a K+ release from glial cells into the extracellular space. Since 5‐hydroxytryptamine is known to be an inhibitory transmitter in the leech central nervous system, this release will occur in regions with inactive neurons, which may be specially well suited for neuronal reaccumulation of K+ ions.
Effect of hypoxia on the superficially exposed carbohydrates of subcellular fractions of guinea pig cerebral cortex
Authors: Rossowska Magdalena
Published: January 2005

Experimental hypoxia led to changes in carbohydrate‐containing macromolecules located on the microsomal and synaptosomal membrane surface. It was found that hypoxia reduced the external membrane‐bound sialic acid content in microsomal and synaptosomal fractions.

On the other hand, a decrease in fucose content of proteins in hypoxic synaptosomal fraction was found. Similarly, a decrease was observed in the amount of 3H‐labeled concanavalin A bound to the microsomal and synaptosomal glycoprotein fractions. Treatment of microsomal and synaptosomal fractions with galactose oxidase followed by reduction with tritiated potassium borohydride resulted in a significantly higher incorporation rate of tritium into the hypoxic membranes. This was accompanied by an increase in the endogenous glycoprotein galactose transferase activity both in microsomal and synaptosomal fractions.
Relationships between γ‐aminobutyrate and succinate cycles during and after cerebral ischemia
Authors: Benzi Gianni , Pastoris O. , Dossena M.
Published: January 2005

Some metabolites (glycogen, glucose, glucose‐6‐phosphate, pyruvate, lactate, citrate, α‐ketoglutarate, succinate, fumarate, malate, glutamate, aspartate, γ‐aminobutyrate, glutamine, alanine, NH+4) were measured in rat cerebral cortex after 5 minutes of complete compression ischemia, as well as after 5, 15, or 30 minutes of recirculation following 5 minutes of ischemia.

Complete ischemia induced a drop of glycolytic substrates and intermediates, consistent with the increase of lactate, succinate, alanine, and γ‐aminobutyrate, and with the decrease of malate, fumarate, and α‐ketoglutarate. These events may be regarded as an expression of the activation of the γ‐aminobutyrate cycle and of the succinate cycle, where succinate itself, in the absence of O2, acts as a terminal electron acceptor.

During post‐ischemic recovery, cerebral parameters tended to normalize, except for the further increase of alanine and the still higher than normal content of both succinate and γ‐aminobutyrate, as an expression of the possible activation of the γ‐glutamyl and γ‐aminobutyrate cycles during recovery.
Effect of ischemia and hypoxia on rat brain glycolipids
Authors: Domańska‐Janik K. , Strosznajder J. , Zalewska T.
Published: January 2005

Hypoxia and ischemia produced the changes in the rat brain lipid composition. Moderate decreases in the content of phospholipids, cerebrosides, and gangliosides were observed. Three different experimental models of oxygen deficiency varied as to the degree of energy disturbances were correlated with their effect on the particular lipid classes. The decrease of cerebrosides content, but not gangliosides and phospholipids, could be attributed directly to energy disturbances and concomitant restriction of glucose supply to the hypoxic‐ischemic brain.
A quantitative ultrastructural study of the pinealocyte of the chipmunk (Tamias striatus) during the daytime and at night
Authors: Karasek Michal , King Thomas S. , Hansen John T. , Reiter Russel J.
Published: January 2005

Day‐night differences in the areas of granular endoplasmic reticulum, Golgi apparatus, dense‐core vesicles, and lysosomelike bodies were analyzed morphometrically in the pinealocytes of the chipmunk. The area of lysosomelike bodies was greater at night and lower during the daytime. In contrast, the areas of granular endoplasmic reticulum and dense‐core vesicles were greater during daytime and lower at night. Our observations suggest the existence of 24‐hour rhythms in the areas of these structures, perhaps indicative of a pineal rhythm in secretion, whether indolic or peptidergic.
Cerebral uptake of amino acids in human subjects and rhesus monkeys in vivo
Authors: Sacks William , Sacks Shirley , Brebbia D. Robert , Fleischer Arthur
Published: January 2005

In experiments with 11 human subjects and 12 rhesus monkeys given 14C‐labeled amino acids intravenously, blood samples were drawn simultaneously from the femoral artery (A) and the superior bulb of the internal jugular vein (V). Analyses of labeled and unlabeled free amino acids indicated that both A‐V and V‐A differences resulted with each amino acid. In no case were there consistent A‐V or V‐A differences (excepting with L‐[methyl‐14C] methionine where consistent A‐V differences resulted). However, in experiments with rhesus monkeys, from 0.2% to 2.3% of the injected 14C‐labeled amino acids was taken up by brains 90–120 minutes after injection. Therefor, it was suggested that, in humans and monkeys in vivo, small but significant amounts of amino acids enter the brain from blood over a period of time by a bidirectional exchange mechanism.
Acceleration of the biosynthesis of rat striatal dopamine by incubation and by administration of γ‐butyrolactone
Authors: Dyck Lillian E. , Kazakoff Clement W.
Published: January 2005

The concentration of dopamine in striatal slices obtained from rats treated with an MAO inhibitor was increasd significantly by a 50‐minute incubatio in oxygenated Krebs buffer at 37°C. Administration of α‐methyl‐p‐tyrosine did not antagonize this small increase in dopamine. The extent of the incubatio‐induced increase was much greater in tissue obtained from control rats and was also greater than that resulting from the intraperitoneal administration of γ‐butyrolactone (GBL). Prior administration of α‐methyl‐p‐tyrosine, d‐amphetamine, apomorphine, or lergotrile significantly antagonized the increases in striatal dopamine levels induced by GBL administration or by incubation of striatal slices obtained from control rats. The prior administration of phenylethylamine, however, antagonized the incubation‐induced, but not the GBL‐induced, increase in striatal dopamine. In conclusion, the effect of incubating striatal slices on their dopamine levels was similar to that of administering GBL in that the incubation enhanced the activity of tyrosine hydroxylase that in turn produced an accelerated synthesis of dopamine.
De novo biosynthesis of nucleotides and of nucleic acids in different regions of developing rat brain: Effect of undernutrition
Authors: Serra I. , Vanella A. , Avitabile M. , Barcellona M. L. , Avola R. , Giuffrida A. M.
Published: January 2005

The effect of undernutrition on the de novo biosynthesis of nucleic acids in cerebral hemispheres, cerebellum, and brain stem of rats at different days of postnatal development was studied. The experiments were carried out in vitro by measuring the incorporation of [14C]‐formate into the adenine nucleotide of the acid‐soluble fraction of RNA and DNA, as well as into the thymine of DNA.

The results obtained indicate that undernutrition during fetal and postnatal development impairs the de novo synthesis of the purine nucleotides of RNA and DNA at 5 days of age and delays it thereafter in the various brain regions examined, particularly in the cerebellum.
Effects of thyroxine on transmembrane resting potentials of skeletal muscle cells in culture
Authors: Sampson S. R. , Bannett Rena R. , Shainberg A.
Published: January 2005

The effect of thyroxine (T4) was studied on the transmembrane resting potential (Em) of rat skeletal muscle cells in culture. In agreement with previous studies, we found the Em of developing muscle cells to increase with age from Day 3 to Day 7 or 8, at which time a plateau is reached. The values of Em we obtained (−65 to −75 mV) were 15–20 mV higher than those (−50 to −55 mV) reported by others. Treatment of mature myotubes with T4 resulted in a significant increase in resting Em. There was only a slight difference between T4‐treated and control cells with regard to the relation between extracellular K+ concentration and resting Em. Within 20–30 min of exposure to ouabain (10−4–10−3M) resting Em of both T4‐treated and control cells had fallen to about the same value. This effect was reversible. Thus, T4 stimulates the activity of an electrogenic Na/K‐ATPase in the membrane of cultured skeletal muscle cells.
Comparison of centrifugation and filtration assays of ligand binding: Do multiple GABA receptive sites exist?
Authors: Patel Shutish C. , Peck Ernest J.
Published: January 2005

Filtration and microcentrifugation procedures for the separation of bound and free ligand are compared for the assay of GABA receptors. The 3H‐GABA and 3H‐muscimol are employed as ligands in saturation analyses of SPM and JC preparations. A direct comparison of the two methods, applied to two membrane preparations and two ligands, reveals that nonspecific binding is consistently higher with the microcentrifugation procedure. Analysis of the binding data yields essentially the same constants in either case; however, the filtration assay provides a better estimate in all cases.
The effect of transmitter antagonists on phasic respiratory neurons
Authors: Wang L. , Boyarsky L. L. , Frazier D. T.
Published: January 2005

The activity of inspiratory neurons in the nucleus tractus solitarius (NTS) and of expiratory neurons in the nucleus retroambigualis (NRA) was recorded during the iontophoresis of L‐glutamate, bicuculline, and strychnine in chloralose‐urethane‐anesthetized cat. Bicuculline methoxide caused increased activity of NTS and NRA neurons during their active or burst phases. Neither bicuculline nor strychnine caused increased activity during the silent phases of NTS or NRA neurons. When neurons were driven to fire during their silent phase by L‐glutamate, the application of bicuculline methoxide caused a diminution of the evoked activity. It is concluded that both inspiratory and expiratory neurons receive inhibitory inputs during both their active and silent phases. Gamma‐aminobutyric acid appears to be gating both the excitatory and inhibitory information to NTS and NRA neurons. Strychnine was generally ineffective in changing the firing patterns of inspiratory and expiratory neurons suggesting a limited role of glycine, taurine, and L‐alanine in the respiratory network.
Metabolic fate of [14C]‐glutamine in mouse cerebral neurons in primary cultures
Authors: Yu A. C. H. , Fisher T. E. , Hertz E. , Tildon J. T. , Schousboe A. , Hertz L.
Published: January 2005

The metabolic fate of L‐[14C]‐glutamine was followed in cerebral cortical neurons in primary cultures, a GABAergic preparation. Part of the glutamine was converted to GABA (0.3 nmol/min per mg protein), which is consistent with the presence of glutaminase and glutamate decarboxylase activity in the cells and with findings by other authors in vivo or in brain slices. However, an even larger part (1.8 nmol/min per mg protein) was converted to CO2 and succinate via an oxidative deamination to α‐ketoglutarate. This is not consistent with the concept that transfer of glutamine from astrocytes to neurons should replenish neuronal GABA stores quantitatively after release of GABA and its partial accumulation into astrocytes, but it is well compatible with the recent demonstration of a net glutamine uptake by the brain.
Glycoproteins and proteins in an axolemma‐enriched fraction and myelin from developing rats: Effect of maternal ethanol consumption
Authors: Gnaedinger J. M. , Druse M. J.
Published: January 2005

The present study examined proteins and glycoproteins from an axolemma‐enriched fraction from the developing offspring of female rats that were pair‐fed control or 6.6% (50 g/liter) ethanol liquid diets on a chronic basis prior to parturition. In addition, this study examined the synthesis of the major CNS myelin‐associated glycoprotein (MAG) as an index of myelin maturation. The results of the latter study demonstrated normal MAG maturation in ethanol‐treated rats. However, a significant decrease in the proportion of radioactivity associated with MAG was found in the developing offspring of ethanol‐treated rats.

The major axolemmal proteins from 32‐day rats included those with molecular weights of 105 K, 81 K, 62 K, 55 K, 52 K, 36 K, and 33 K. Major peaks of radioactivity were associated with fucosylated axolemmal glycoproteins with apparent molecular weights of 150 K, 130 K, 85 K, 76 K, and 64 K. Several development‐related changes in the protein composition of axolemma‐enriched fractions were observed in control animals. Between 22 and 32 days of age control rats exhibited a significant (P <.05) decrease in the proportion of axolemmal proteins that had apparent molecular weights of 150 K, 105 K, and 62 K. A development‐related decrease in the 105 K axolemma‐associated protein did not occur during the 22–32‐day age period in the offspring of ethanol‐treated animals. At 22 days the proportion of this 105 K protein in affected offspring was significantly (P <.05) less than that in age‐matched control rats and comparable to that in 32‐day control rats. The relative distribution of radioactivity among fucosylated axolemmal glycoproteins also changed significantly between 22 and 32 days of age. These changes include a decrease in the proportion of radioactivity associated with the 110 K, 55 K, and 52 K fucosylated glycoproteins and an increase in the proportion of radioactivity associated with the 85 K and 67 K glycoproteins. Several small, but significant (P <.05) alterations were found associated with glycoproteins in an axolemma‐enriched fraction from 22‐ and 32‐day ethanoltreated rats.
Ultrastructural organization of posterior and anterior barrels in the somatosensory cortex of rat
Authors: Patel‐Vaidya U.
Published: January 2005

The somatosensory barrels in layer IV of rat cerebral cortex were studied on uniformly oriented, serial, tangential sections by a combination of light microscope and ultrastructural techniques. Section orientation between sections was maintained by blood vessel patterns. The principal elements of both anterior and posterior barrels were quantified and analyzed in relation to proportional content and nonrandom spatial arrangement over depth in layer IV. Elements studied in this manner included neurons, myelinated axons, apical dendrites, synapses, glial cells, and blood vessels. In general, constituents were found to be arranged in a highly ordered fashion similar to other discretely organized sensory cortical areas. Myelinated axons outlined the basic structure of the barrels with the osmium stainig employed. Neurons appeared organized in small clusters. In addition apical dendrites, synapses, and blood vessels also exhibited nonrandom distribution complementary to the organization of axons and neurons. Anterior and posterior barrels differed slightly in their organization of elements.
Neuroimmunology of gangliosides in human neurons and glial cells in culture
Authors: Kim S. U. , Moretto G. , Lee V. , Yu R. K.
Published: January 2005

Gangliosides (sialic‐acid‐bearing glycolipids) have received attention in recent years because of their role in cell recognition phenomena, synaptic transmission, memory generation, and nerve regeneration in the fields of neurosciences. It is suggested that each brain region or each neural cell type may contain a specific and characteristic set of gangliosides.

We have investigated the immunocytochemical localization of several classes of gangliosides that include GM1, GM4, GD3, and GQ gangliosides on the cell surface of various cell types found in human neural cell cultures with antibodies specific for these gangliosides. Cell cultures were obtained from adult human brains and fetal human dorsal root ganglia and spinal cord and cultured in vitro for the period up to 6 months and utilized for the ganglioside immunocytochemistry.

It was demonstrated that (1) GM1 ganglioside was present in all galactocerebroside‐positive oligodendrocytes and most of glial fibrillary acid protein (GFAP)‐positive astrocytes (80%), most of neurofilament‐positive neurons (80%), 50–70% of Schwann cells, and 5–10% of fibronectin‐positive fibroblasts; (2) GM4 ganglioside could be detected in all oligodendrocytes, 80% of astrocytes, and 50% of Schwann cells, while no staining was found in neurons or fibroblasts; (3) GD3 ganglioside was present in all oligodendrocytes and 5–10% of astrocytes but not in neurons, Schwann cells, or fibroblasts; and (4) all of fetal CNS neurons and approximately 80–90% of fetal dorsal root ganglia (DRG) neurons and a small percentage of astrocytes (10–20% in fetal and <1% in adult astrocytes) was labeled by A2B5 antibody which is specific for GQ ganglioside, while this antibody did not stain cell surface of oligodendrocytes, Schwann cells, or fibroblasts.

Three classes of gangliosides, GM1, GM4, and GD3 were found to be definite components of fetal and adult human oligodendroglial plasma membrane, while GM1 and GM4 gangliosides were detected on the surface of most astrocytes. Only a minor population of astrocytes from both fetal and adult human CNS contained GD3 and GQ gangliosides. Two classes of gangliosides, GM1 and GQ, were detected on the surface of fetal human neurons. More than half of fetal Schwann cells reacted to GM1 and GM4 antibodies but did not to GD3 or GQ antibodies. We recognized the presence of a specific and characteristic set of gangliosides on the cell surface of different human neural cell types and these findings should facilitate further investigation of the precise biological activity of these gangliosides.
Astrocyte culture on nitrocellulose membranes and plastic: Detection of cytoskeletal proteins and mRNAs by immunocytochemistry and in situ hybridization
Authors: Eng L.F. , Stöcklin E. , Lee Y.‐L. , Shiurba R.A. , Coria F. , Halks‐Miller M. , Mozsgai C. , Fukayama G. , Gibbs M.
Published: January 2005

Neonatal rat brain astrocyte secondary cultures were established on nitrocellulose membrane filters (13‐mm diameter MilliporeTM disk) and on plastic coverslips in serum‐supplemented medium. On these substrata, cultured astrocytes changed their shape from flat and polygonal to stellate in the absence of hormones or growth factor supplements. Cultures became confluent after 4 days, and astrocytes on nitrocellulose filters continued to differentiate morphologically and biochemically, as evidenced by extensive cytoplasmic process formation and glial fibrillary acid protein (GFAP) accumulation. Cultures were immunostained for GFAP and vimentin. mRNAs to GFAP, vimentin, alpha and beta tubulin, and actin also were detected by in situ hybridization with biotinylated cDNA probes. The astrocyte culture method on nitrocellulose provides a simple, versatile means of comparing undifferentiated, morphologically mature, reactive, and neoplastic astrocytes in vitro.
Biological activity of region 65–102 of the myelin basic protein
Authors: Hashim G.A. , Day E.D. , Fredane L. , Intintola P. , Carvalho E.
Published: January 2005

Region 65‐102 of the myelin basic protein (MBP) houses a number of antigenic determinants known to induce delayed‐type hypersensitivity, experimental allergic encephalomyelitis (EAE), suppressor cell function, and antibodies. In this report we describe the biological activity of synthetic peptides S53, S55, and S49 with sequence homology to region 69‐84 of the rat, guinea pig, and bovine MBP, Peptide S53‐A, defined by residues 75‐84 of the guinea pig (SQRSQDEN) and of the rat (SQRTQDEN) MBP induced clinical signs of disease in Lewis rats. These included weight loss, flaccid tail, “muscle wasting” and hind‐leg weakness. Histological examination of brain, spinal cord, and sciatic nerve sections of diseased rats revealed the complete absence of focal and perivascular lymphocytic infiltrates characteristic of demyelinating EAE lesions. Elongation of peptide S53 by three or six residues to residue sequences naturally found at its N‐terminal end gave rise to peptides S55S (PQKSQRSQDEN) and S49S (GSLPQKSQRSDQDEN), respectively. Lewis rats challenged with either S55S or S49S developed classical clinical and histological signs of EAE. Severe hindleg paralysis was accompanied by incontinence and sometimes death. Injected in the form of carrier‐free peptide, S53 was a meager B cell immunogen. S53 conjugated with methylated‐bovine serum albumin was also a potent immunogen and produced clinical signs of disease without CNS pathology. By comparison, carrier‐free S55S and S49S were potent immunogens giving rise to antibodies that cross reacted completely and competitively with S55S but considerably less so with S53. The results show that the sequence of S53 defines an epitope responsible for the formation of anti‐S53 antibodies. Elongation of the S53 sequence at its N‐terminal end generated an additional epitope which induced cell‐mediated immunity responsible for the concomitant development of pathological signs of EAE. It may be concluded that the induction of classical signs of EAE requires specific and defined sequences capable of expressing both B cell and T cell functions.
Partial characterization of chicken Thy‐1 glycoprotein by monoclonal antibodies
Authors: French P.W. , Jeffrey P.L.
Published: January 2005

A panel of monoclonal antibodies has been raised to Thy‐1 purified from chicken brain. They were produced by immunization of Balb/c mice with a Thy‐1‐enriched (Sephacryl B) fraction of a lentil lectin‐positive fraction from solubilized brain membrane proteins. Antibody‐secreting clones were found to be specific for Thy‐1 by enzyme‐linked immunosorbent assay (ELISA) and Western transfer and immunoblotting. Four of the monoclonal antibodies were of the IgG2b isotype, one was IgG1, and one was IgM. In additivity and competition ELISA, it was found that three of the antibodies bound to the same (or similar) epitopes, and three had different epitope specificities. These monoclonal antibodies have been used to examine the development and distribution of Thy‐1 in the central nervous system of the chicken.
The survival of adult mouse sensory neurons in vitro is enhanced by natural and synthetic substrata, particularly fibronectin
Authors: Smith R. A. , Orr D. J.
Published: January 2005

Primary cultures derived from adult mouse dorsal root ganglia have been maintained in the presence or absence of 5 × 10 −6M cytosine arabinoside for periods of up to 4 weeks. In cultures in which cytosine arabinoside is present, the non‐neuronal cell population is effectively reduced. When uncoated plastic substrata are used there is also a concurrent decrease in the number of neurons if the medium is supplemented with cytosine arabinoside. The effects on neuron survival of substrata coated with fibronectin, polyornithine, polylysine, and exudates prepared from mouse liver cells were studied. It was shown that neuronal densities similar to those with uninhibited media may be retained in the presence of cytosine arabinoside if fibronectin‐coated substrata are prepared. With the other coating agents neuronal survival was also enhanced but to a lesser extent. The study offers a means therefore of producing purer cultures of dorsal root ganglia neurons than has previously been possible from adult mammalian sources.
Nonresident macrophages in peripheral nerve of rat: Effect of silica on migration, myelin phagocytosis, and apolipoprotein E expression during wallerian degeneration
Authors: Müller H. W. , Minwegen P.
Published: January 2005

The selective toxicity of silica quartz dust to macrophages was used to assess the role of these cells in Wallerian degeneration and nerve repair. Left sciatic nerves of adult Wistar rats were crushed and one group of animals received repetitive intraperitoneal injections of silica (200 mg two times per week starting 1 day prior to injury), whereas the control group received saline. Unexpectedly, silica treatmen did not impair the initial invasion of (hematogenous) macrophages into the degenerating dital nerve stump as revealed by histological and immunocytochemical methods. However, 4 weeks after the lesion three specific events in Wallerian degeneration were significantly inhibited in silica‐treated animals: (1) inhibition of phagocytosis and degradation of myelin, (2) delay in disappearance of nonresient macrophages from regenerating nerve, (3) reduction of synthesis and/or secretion of apolipoprotein E in resting macrophages. On the other hand, axonal regrowth and remyelination were not affected by silica. These in situ experiments support and extend previous studies suggesting specific function for nonresident macrophages in wallerin degeneration of peripheral nerve.
Release of acetylcholinesterase from the caudate nucleus of the rat
Authors: de Sarno P. , Giacobini E. , Downen M.
Published: January 2005

Acetylcholinesterase (AChE)can be released in the Perfusate of rat caudate nucleus (CN) slices by two different modes of stimulation, with electrical stimulation at 5Hz and with high concentrations of K+ (105 mM) using K+ ‐propionate. We were unable to demonstrate AChE release with lower K+ concentrations (50 mM); however, at this concentration the drop in AChEactivity seen in resting conditions was prevented. Practicfallyb all (95%) cholinesterase (ChE)found in the rat CN is AChE, which is reprersented by tow major molecular forms (4S and 10S). In the perfusate, only AChE activity could be detected. A comparison of acetylcholine (ACh) and AChE release showed that maximal 3H‐outflow and AChE release occurred at the same frequency (5 Hz), but the onsetof AChE release was delayed. With high K+ (105mM) depolarization, AChE release started after termination of the stimulation and continued for at least 50 min. These findings are consistent with the view that soluble form(s) of AChE can be slowly released from neurons under specific conditions of depolarization. In the caudate of the rat, the most likely sites for this release are processes of chlinergic interneurons. A hypothesis of AChE release is presented, and possible physiological and pathological implications of such a mechanism are discussed.
Topical application of morphine to the rat somatosensory corte produces analgesia to tonic pain
Authors: Soto‐Moyano R. , Galvez J. , Vallejos C. , Hernandez A.
Published: January 2005

Topical application of 0.01 or 0.1% morphine solution to the somatosensory SI area of the rat cerebral cortex significantly decreased the pain intensity rating in the formalin test without producing motor side efects or senory deficits. Naloxone of morphine to the stirate cortex did not induce analogesia. It issuggested that the primary somatosensory SI area of the cerebral cortex plays a role in opiate pain control.
Adenosine stimulates cAMP‐mediated taurine release from LRM55 glial cells
Authors: Madelian V. , Silliman S. , Shain W.
Published: January 2005

The possible role of adenosine as a modulator or transmitter in the central nervous system was tested by measuring its effects on LRM55 astroglial cells. Two related cellular responses were measured–receptor activated increases in intracellular cAMP and cAMP‐mediated taurine release. Taurine is a neuroinhibitory amino acid that is taken up, stored, and released from primary cultures of astrocytes and astroglial cells. Three‐minute incubations of cells with adenosine caused a dosedependent accumulation of intracellular cAMP and release of the taurine (EC50 = 5.0 × 10−5 M and 1.6 × 10−6 M, respectively). That the cellular responses were mediated through the activation of specific adenosine receptors was indicated by the observations that the adenosine receptor antagonist isobutylmethylxanthine (IBMX) but not the beta‐adrenergic receptor antagonist 1‐propranolol inhibited responses to adenosine. The study of various adenosine analogs showed a rank order of potency (chloroadenosine = 5′‐(N‐ethyl)carboxamidoadenosine > N6‐(L‐2‐phenylisopropyl)‐adenosine > cyclohexyladenosine = cyclopentyladenosine) characteristic of the low affinity A2‐type adenosine receptors that have been associated with cAMP elevation in several tissues. These results indicate that, in addition to directly affecting neurons, adenosine may have a primary site of action on astroglial cells resulting in taurine release and subsequent inhibition of neuronal activity.
Ganglioside GM1 actions on cell‐substratum adhesion and DNA synthesis by cultured astroglial cells
Authors: Pettmann B. , Manthorpe M. , Varon Silvio
Published: January 2005

Cultures of rat astroglial (AG) cells treated with the ganglioside GM1 in serum‐free medium respond with an increase in DNA labeling and cell proliferation. However, GM1 doses above 60 μM cause decreasing DNA labeling to levels even below that determined in the absence of added GM1. Quantitative determination of cell numbers in 24‐hr cultures treated with various GM1 concentrations shows no loss of cells but a progressive shift in cell morphology from the usual flat to a rounded shape, suggesting a GM1‐induced progressive reduction in cell‐substratum adhesion. The rounded cells, which can be readily washed off the culture wells, do not carry out measurable DNA synthesis but do appear normal by several other biochemical measurements. All the GM1‐treated rounded cells can regain their flat morphology and resume DNA synthesis and cell replication if fetal calf serum is added to the medium. We conclude that modulation of cell adhesion is a major component of astroglial cell responses to exogenous ganglioside treatment.
Immortalization of bipotential glial progenitors and generation of permanent “blue” cell lines
Authors: Evrard C. , Galiana E. , Rouget P.
Published: January 2005

The transfer of the adenovirus 5 E1A gene into brain cells from rat embryos led to the establishment of phenotypically untransformed clonal glial cell lines. Some lines displayed properties of oligodendrocyte‐astrocyte progenitors. Their differentiation involved several steps that were dependent on culture conditions and cell interactions. Subsequently, a few lines were cotransfected with a vector carrying a modified dihydrofolate reductase gene and with the Escherichia coli lacZ gene. After selection for resistance to methotrexate, cell lines were derived that stably expressed the lacZ gene. These cells were individually detectable by histochemical staining for β‐galactosidase activity, even in the presence of other cells. These results suggest that this type of cell line could be of interest for further in vitro, and possibly transplant, studies of the differentiation and interactions of glial cells.
Gliogenesis in rat spinal cord: Evidence for origin of astrocytes and oligodendrocytes from radial precursors
Authors: Hirano M. , Goldman J. E.
Published: January 2005

We have examined glial cell lineages during rat spinal cord development by using a variety of antibodies that react with immature and mature glia. Radial glia in embryonic cord bound (1) A2B5, an antibody that reacts with a glial precursor cell population in optic nerve; (2) AbR24, which is directed against GD3 ganglioside and binds to immature neuroectodermal cells and to developing oligodendrocytes in forebrain and cerebellum; and (3) an antibody to the intermediate filament, vimentin. With time, two different populations emerged, both of which seemed to be derivatives of radial cells. One cell type expressed the astrocyte intermediate filament, GFAP, in addition to vimentin. GFAP‐containing cells eventually took on the forms of astrocytes in gray and white matter. The other type expressed carbonic anhydrase, an enzyme characteristic of oligodendrocytes and enriched in myelin. Carbonic anhydrase‐positive cells eventually developed into small cells with oligodendrocyte morphology. Our observations suggest a common lineage for astrocytes and oligodendrocytes from radial cells during spinal cord gliogenesis.
Expression of 48‐kilodalton intermediate filament‐associated protein in differentiating and in mature astrocytes in various regions of the central nervous system
Authors: Abd‐El‐Basset E. M. , Kalnins V. I. , Fedoroff S.
Published: January 2005

In this paper we present evidence that the 48‐kD intermediate filament‐associated protein (IFAP) is expressed relatively late in maturation of astrocytes, after they have acquired the glial fibrillary acidic protein (GFAP). In the astrocyes of white matter in the cerebellum the GFAP is detected at P3, whereas the 48‐kD IFAP is detected only at P11. In the periventricular region and the hippocampus the 48‐kD IFAP was detected at P6, long after the appearance of GFAP. In adult mice the 48‐kD IFAP was observed in GFAP‐positive astrocytes in the white matter of cerebellum, spinal cord, brainstem, and corpus callosum as well as in GFAP‐positive cells in the grey matter of cerebral cortex and spinal cord.

The 48‐kD IFAP was not, however, detected in radial glia and their derivatives, in Bergmann glia or in Müller glia. Thus, not all the GFAP‐positive astroglia express the 48‐kD IFAP. Similarly, 48‐kD IFAP was not detected in cells which were GFAP‐negative.
HLA‐DRβ, ‐DQα, and ‐DQβ restriction fragment length polymorphisms in multiple sclerosis
Authors: Haegert D. G. , Michaud M. , Schwab C. , Tansey C. , Décary F. , Francis G.
Published: January 2005

Restriction fragment length polymorphism (RFLP) studies were performed on DNA from unrelated Caucasian patients with multiple sclerosis (MS) using cDNA probes to the HLA class II genes DRβ, DQα, and DQβ. In a study of 34 patients and 34 controls who were not matched for DR type, we found that the DQβ allele‐specific RFLP or allogenotype, termed DQβlb, which corresponds at the molecular level to the DQwl serotype, is preferentially associated with MS. A significant disease association with DR2 was demonstrated by serology but this was not confirmed using DR2/Dw2‐specific RFLPs. We suggest that DQβlb is largely responsible for HLA‐associated susceptibility to MS and that the apparent MS‐DR2 serological association is due to the strong linkage disequilibrium between DR2 and DQβlb.

Homozygosity of one of the two allelic bands of the DX α gene, usually termed the DXα lower (DXαL) band (which cross‐hybridizes with the DQα probe), correlated with reduced susceptibility to MS. Similarly a 5.3 kb band identified by the DQα probe in Mspl digests showed a negative correlation with MS.

In an analysis of 27 DR2+ controls and 26 DR2+ patients it was found that these individuals all had DR2/Dw2‐specific RFLPs and all had identical DR2/Dw2‐associated DQβ (DQβlb) and DQα (DQαlb) allogenotypes. We detected no polymorphisms of DRβ, DQα, or DQβ genes among the DR2+ MS patients which distinguished them from normals. This suggests that the various HLA class II genes associated with MS are normal and not variant alleles.

Because of strong linkage disequilibrium, a particular DRβ allogenotype in Caucasians is characteristically associated with specific DQα and DQβ allogenotypes. However, approximately 20% of all MS patients studied showed anomalous DR‐DQ associations including absence of anticipated allogenotypes or inappropriate allogenotypes. This result suggests that in at least some cases, aberrant DR‐DQ associations may be important in the pathogenesis of MS.
Chronic L‐deprenyl does not alter the restoration of striatal dopamine in MPTP‐lesioned mice
Authors: Wiener H. L. , Hashim A. , Lajtha A. , Sershen H.
Published: January 2005

The present study examined the effect of chronic L‐deprenyl on dopaminergic terminal function after mouse striatal terminals were lesioned with 1‐methyl‐4‐phenyl‐1, 2, 3, 6‐tetrahydropyridine (MPTP; 2 × 30 mg/kg s.c.). In the MPTP‐lesioned mice, the level of dopamine was decreased by 59% 1 week after MPTP administration and by 22% at 16 weeks. Chronic administration of L‐deprenyl (0.1 mg/kg, once weekly for up to 16 weeks) did not alter striatal dopamine metabolism, although monoamine oxidase B activity was reduced by 50% during this 16‐week period, and did not alter the rate of restoration of the level of striatal dopamine.
Herpes simplex virus type I infection of the CNS induces major histocompatibility complex antigen expression on rat microglia
Authors: Weinstein D. L. , Walker D. G. , Akiyama H. , McGeer P. L.
Published: January 2005

Rats were infected with herpes simplex virus type I (HSV‐1) by corneal scarification. The spread of virus in the brain, the infiltration of leucocytes into infected areas, and the expression of major histocompatibility complex (MHC) glycoproteins by brain cells were assessed as a function of time by immunohistochemistry. Virus moved along neuronal pathways, achieving widespread distribution in the brain by days 8–10 when the illness appeared most severe. Granulocytes, T‐lymphocytes, and monocytes infiltrated the tissue matrix at sites of infection. Microglial cells were induced to express MHC class I and class II glycoproteins. Reactive microglia near the sites of infection most vigorously expressed such glycoproteins. At the peak of the infection they were detectable on microglia throughout the brain, including areas apparently separated from unfection. Evidence of viral antigens, as well as microglial MHC expression, had largely disappeared by day 30. Neurons, astrocytes, and oligodendroglial cells failed to express MHC antigens.
Cerebellar ganglioside abnormalities in pcd mutant mice
Authors: Seyfried T. N. , Yu R. K.
Published: January 2005

The distribution of cerebellar gangliosides was studied in Purkinje cell degeneration (pcd/pcd) mutant mice at postnatal days 25, 30, 50, and 150. These mutants lose the majority of Purkinje cells between 18 and 50 days of age. A reactive gliosis accompanies Purkinje cell loss and a partial loss of granule cells occurs in pcd/pcd mice older than p50. Purkinje cell loss is associated with significant reductions in cerebellar weight and ganglioside concentration. This neuronal loss was also developmentally correlated with reductions of gangliosides GT1a/LD1 and GT1b and with elevations of GD3. These results agree with previous findings in other cerebellar mutants that GT1a/LD1 and GT1b are concentrated in Purkinje cells and that GD3 is enriched in reactive glial cells. A slight, but significant, reduction in GD1a concentration occurred only in older pcd/pcd mice, consistent with previous findings in weaver and staggerer mice that GD1a is enriched in mature granule cells. The findings with pcd/pcd and other neurological mutants indicate that certain gangliosides can serve as cell‐surface markers for monitoring changes in cerebellar cytoarchitecture that accompany development or disease.
Induction of heat shock (stress) genes in the mammalian brain by hyperthermia and other traumatic events: A current perspective
Authors: Brown I. R.
Published: January 2005

Is the heat shock response physiologically relevant? For example, following hyperthermia or ischemia, what neural cell types show induction of heat shock genes and what is the time course of the effect? Initial experiments in this area demonstrated the prominent Induction of a 70 kDa heat shock protein (hsp70) when labeled brain proteins isolated from hyperthermic animals were analyzed. Recently, in situ hybridization and immunocytochemistry have been utilized to map out the pattern of expression of both constitutively expressed and stress‐inducible members of the hsp70 multigene family. Different types of neural trauma have been found to induce characteristic cellular responses in the mammalian brain with regard to the type of brain cell that responds by inducing hsp70 and the timing of the induction response. Fever‐like temperature causes a dramatic induction of hsp70 mRNA within 1 hr in fiber tracts of the fore‐brain and cerebellum, a pattern consistent with a strong glial response to heat shock. Tissue injury, namely, a small surgical cut in the cerebral cortex, induces a rapid and highly localized induction of hsp70 mRNA in cells proximal to the injury site. Using an immunocytochemical approach, a neuronal pattern of induction of hsp70 has been demonstrated following ischemia or kainic acid–induced seizures. It is apparent that the pattern of induction of hsp70 may be a useful early marker of cellular injury and may identify previously unrecognized areas of vulnerability in the nervous system.
Cobalt‐Dependent potentiation of net inward current density in Helix aspersa neurons
Authors: Kim Y‐K. , Woodruff M. L.
Published: January 2005

A low concentration of transition metal ions Co2+ and Ni2+ increases the inward current density in neurons from the land snail Helix aspersa. The currents were measured using a single electrode voltage‐clamp/internal perfusion method under conditions in which the external Na+ was replaced by Tris+ the predominant external current carrying cation was Ca2+ and the internal perfusate contained 120 mM Cs+/0 K+; 30 mM tetraethylammonium (TEA) was addedexternally to block K+ carrent. In presence of Co2+ (3 mM) Ni2+ Ca2+ currents were stimulated normally by voltage‐dependent activation of Ca2+ channels. There was a 5‐10% decrease in the rate of rise of the inward current The principal effect of Co2+ and Ni2+ current density seems to be a decrease in the rate at which the inward currents decline during a depolarizing voltage pulse. The results may be due to a decrease in a voltage‐dependent or Ca2+‐dependent outward current and/or an inhibition of Ca2+ channel inactivation. Outward current under these conditions (zero internal K+) was significant and most likely due to Cs+ efflux through the voltage activated or Ca2+‐activated nonspecification channels. Co2+ is an extremely effective blocker of this outward current. These results are not an artifact of internal perfusion or the special ionic conditions. Intracellular recording of unperfused neurons in normal Helix Ringer solution showed that the Ca2+‐dependent action potential duration was increased significantly by low concentrations of Co2+. This result is consistant with the Co2+ ‐dependent increase in inward (depolarizing) current seen in voltage‐clamp experiments.