bluuebunny/crossref_metadata_2025_split huggingface dataset:
Purification of L‐Glutamate decarboxylase from rabbit brain and preparation of a monospecific antiserum
Authors: Brandon C. 
Published: January 2005

AbstractL‐Glutamate decarboxylase (GAD), the enzyme responsible for the biosynthesis of gamma‐aminobutyric acid, has been purified from rabbit brain and used for the production of a monospecific rabbit antiserum. The enzyme was purified approximately 500‐fold by a combination of ion exchange, hydrophobic, hydroxyapatite, and gel filtration column chromatography, and preparative polyacrylamide gel electrophoresis. The preparation thus obtained was injected into a rabbit, producing a polyspecific antiserum. This first antiserum was used for the preparation of an immunoprecipitate containing GAD; injections of the immunoprecipitate into a second rabbit led to the production of a second, monospecific anti‐GAD serum. The specificity of the antiserum for GAD has been demonstrated by enzyme precipitation, immunodiffusion, line immunoelectrophoresis, gel filtration chromatography of GAD/anti‐GAD immune complexes, and immunocytochemistry in the rat cerebellum.
Binding sites for glycosaminoglycans on developing sympathetic neurones
Authors: Vidovic M. , Hill C. E. , Hendry I. A. , Parish C. R. 
Published: January 2005

AbstractRecent studies have suggested that cell to cell communication in the immune system is mediated by cell surface receptors for glycosaminoglycans (GAGs) [Parish et al, 1984]. The intention of this study was to see whether similar recognition molecules for GAGs are present on sympathetic neurones. A mechanical dissociation technique was used to isolate neurones from superior cervical ganglia (SCG) of rats aged between gestational day 19 and postnatal day 21. Receptors for GAGs on sympathetic neurones were detected by the ability of neurones to form rosettes with sheep red blood cells coupled with one of 12 different GAGs. It was found that SCG cells bind to all the GAGs tested. In addition, a range of developmental binding patterns for the various GAGs was found.
Chick embryo myotubes contain transferrin receptors and internalize and recycle transferrin
Authors: Stamatos C. , Fine R. E. 
Published: January 2005

AbstractEmbryonic chick skeletal myotubes grown in cell culture require transferrin to provide iron for proliferation and differentiation. We demonstrate here that cultured myotubes contain transferrin receptors as demonstrated by the finding of specific, saturable, and reversible high‐affinity binding sites. Scatchard analysis of equilibrium binding data indicates an apparent Kd of 37 nM and one muscle cell equivalent contains 7,500 transferrin receptors. Myotubes exhibit a Kd 100 times higher for apotransferrin than for iron‐saturated transferrin.Internalization of specifically bound transferrin is temperature dependent and occurs rapidly at 37°C with a steady state reached after 10 min. Internalization studies using either 125I‐ovotransferrin or 55Fe‐ovotransferrin suggest that transferrin is internalized, depleted of iron, and recycled intact to the extracellular medium as shown in other cell systems. Autoradiography of muscle cell cultures incubated with 125I‐ovotransferrin at 4°C reveals clusters of receptors along the myotubes.The possible mechanisms by which transferrin is supplied to muscle in vivo are discussed in light of the evidence that motor neurons contain transferrin.
A biomolecular approach to the study of the expression of specific genes in the retina
Authors: McGinnis J.F. , Leveille P.J. 
Published: January 2005

AbstractThe central nervous system contains a number of populations of neurons that are morphologically and functionally distinct. To study the genes responsible for the development and maintenance of proteins with unique structural and biochemical properties, polyspecific antisera were produced against normal mouse retinal proteins and used in combination with the rd (retinal degeneration) neurological mutant of the mouse to immunologically identify specific retinal proteins. Western transfer analysis of the proteins present in normal and in mutant retinas identified three classes of neural proteins: (1) those found only in normal retina; (2) those found in normal and in photoreceptorless retinas but not in other tissues; and (3) those found in both normal and mutant retinas, as well as in brain, but not elsewhere. Some of these class 1 proteins were shown to be present in the retinas of other species, including humans, suggesting their importance in the process of vision. The poly A + RNA was isolated from the retinas of normal mice and used to generate a cDNA expression library in lambda gt‐11. This library was screened with polyspecific antisera absorbed with the proteins present in mutant retina, and a number of immunologically positive plaques were cloned. Four of these were shown to code for rhodopsin, the major visual protein in mammalian retinas. The approach described is applicable to other systems in order to generate specific immunological and recombinant DNA probes for examining the expression of specific genes during development and differentiation.
Chronic antidepressant treatment and mouse brain 3H‐imipramine binding
Authors: Severson J.A. , Anderson B. 
Published: January 2005

AbstractChronic pretreatment of mice with the monoamine oxidase type B inhibitor (–) deprenly resulted in an increase in the density of cerebral cortical 3H‐imipramine binding sites and a decrease in the density of cerebral cortical beta‐adrenergic receptors. In contrast, pretreatment of mice with the tricyclie antidepresents imipramine and desipramine did not alter the density of cerebral cortical 3‐Himipramine binding sites. Imipramine and desipramine treatment decreased the density of beta‐adrenergic receptors. Haloperidol pretreatment resulted in an increase in the density of striatal D‐2 dopamine receptors, but did not alter the density of cerebral cortical 3H‐imipramine binding sites or beta‐adrenergic receptors. These data suggest that brain 3H‐imipramine binding sites can be regulated by pharmacological pretreatment, but that this regulation may not occur for all antidepresents.
Immunocytochemical localization of nerve growth factor in mouse kidney
Authors: Salido E.C. , Barajas L. , Lechago J. , Laborde N.P. , Fisher D.A. 
Published: January 2005

AbstractThe presence of NGF in mouse kidney was investigated using immunocytochemical methods. Female and male adult Swiss‐Webster mouse kidneys were fixed by perfusion with 4% paraformaldehyde or Zamboni's fixative. The kidneys were forzen, and serial sections were prepared. Rabbit NGF antiserum was used for the primary incubation, and the avidin‐biotin complex immunoperoxidase procedure was utilized for immunostaining. NGF immunorectivity was localized in the apical and perinuclear cytoplasm of cells linig the late is distal nephorn, in a portion that corresponds to the connecting tubule. This portion of the nephron has been consistently observed in close anatomical to relationship with arterioles, which are known to be richly innervated. Some cells of the connecting tubule, correspondind to intercalated cells, lacked NGF immunoreactivity.
Heterogeneity of sodium‐dependent excitatory amino uptake mechanisms in rat brain
Authors: Ferkany J. , Coyle J.T. 
Published: January 2005

AbstractThe pharmacologic and kinetic characteristics of sodium‐dependent uptake of [3H] L‐glutamate, [3H] D‐aspartate, and [3H] L‐aspartate into crude synaptosomal preparations of rat corpus striatum and ecrebellum have been examined in vitro. In cerebellum the apparent Kt s and Vmax for the three excitatory amino acids were identical whereas in striatal synaptosomes, the Vmax for [3H] L‐glutamate was 30% greater (P≤.001) than for [3H] D‐aspartate and 50% greater (P ≤.001) than for [3H] L‐aspartate. L‐Amino adipic acid inhibited the uptake of the three amino acids in both regions of brain but was 15‐ to 20‐fold more potent in cerebellum than in striatum. In contrast, dihydrokainic acid inhibited transport processes in the corpus straitum but was without activity in cerebellar preparations. The neurotoxin kainic acid blocked only a portion (60%) of [3H] L‐glutamate and [3H] D‐aspartate uptake in cerebellum while completeley inhibiting amino acid trasport in corpus striatum. Three days post kainic acid lesion, [3H] D‐aspartate uptake was attenuated more than [3H] L‐glutamate uptake in the corpus straitum; destruction of corticostriatal afferents reduced [3H] L‐glutamate to a greater extent than [3H] D‐aspartate. Various lesions of the cerebellum affected excitatory amino acid transport processes to a similar extent. These results suggest that excitatory amino acid transport systems are pharmacologically distinct in different brain regions and may be heterogeneous within a single region.
Effects of hormone therapy on the central cholinergic neurotransmission of the snell dwarf mouse
Authors: Fuhrmann G. , Kempf E. , Ebel A. 
Published: January 2005

AbstractEffects of growth and thyroid hormone therapy on central cholinergic neurotransmission has been followed in the cholinergic‐deficient Snell dwarf mouse. Growth hormone and thyroxine can reverse the neurotransmission impairment even in adulthood. Furthermore, it appears that in the dw/dw mouse, hormone deficiency becomes determinant only after the critical period of neurogenesis, in a late postnatal developmental stage. At first sight, these observations show that the distrubed cholinergic neurotransmission of the mutant might be linked to the pituitary and thyroxine deficiency that is characteristic of this mouse. Hormone therapy selectively stimulates cholinergic activity in cholinergic‐deficient structures, where it reactivates presynaptic markers. The differential responsiveness of the neuroanatomical and neurochemical targets could be linked to different regulatory hormone effects or to timing in respect to sensitivity to hormones during development.
Double isotopic method using dansyl chloride for the determination of GABA in rat C6 astrocytoma cell cultures
Authors: Kohl R.L. , Quay W.B. , Perez‐Polo J.R. 
Published: January 2005

AbstractMethods are described for the quantitative measurement of GABA in culture. The method can be adapted to any amino acid or dansyl‐chloride‐reactive species. The sensitivity and selectivity of the procedure result from the double isotopic design in which (14C)‐labeled internal standard was added to the samples before reaction with (3M)‐labeled dansyl chloride. Values obtained by ion‐exchange amino acid analysis of cultures agree closely with the values obtained by the double isotopic method. This method is sensitive enough to measure GABA intracellularly and the condition medium.
Effects of naloxone and morphine on cerebral ischemia in gerbils
Authors: Christie‐Pope B.C. , Palmer G.C. , Palmer S.J. 
Published: January 2005

AbstractA therapeutic role for naloxone during stroke has been suggested, but a neurochemical site of action remains to be determined. Previous work with the geerbil cerebral cortex has shown that either bilateral secondary ischemia (60‐min occlusion of the carotid arteries followed by 40‐min reflow) or unilateral primary ischemia (permanent ligation of one carotid artery for 6 hr in symptomatic animals) produced deficits in both Na+, K+‐ATPase (EC 3.6.1.3) activity and various parameters of activation of adenylate cyclase (EC 4.6.1.1). Pretreatment of gerbils with either naloxone or morphine failed to ameliorate or exacerbate, respectively, the neurological signs of ischemia; however, morphine did reduce mortality. Infusion of naloxone prior to ischemia afforded varying degrees of protection to forskolin, GTP analogs, and NE (norepinephrine) activation of adenylate cyclase, as well as to Na+, K+‐ATPase (bilateral ischemia only). Similarly, morphine inhibited damage to basal activity of adenylate cyclase and to stimulation by NE, forskolin, and Gpp (NH)p (5′‐guanylyl imidodiphosphate). Under in vitro conditions morphine increased the basal activity of adenylate cyclase but reduced responses to NE and forskolin. Furthermore, morphine injected into control gerbils elevated basal‐ and forskolin‐elicited activities but reduced the activation of adenylate cyclase by NE.
Effects of arginine vasopressin on protein phosphorylation in rat hippocampal synaptic membranes
Authors: Hinko A. , Pearlmutter A. F. 
Published: January 2005

AbstractOur laboratory has reported previously the characteristics of specific AVP binding to rat hippocampal synaptic membranes (SPM) in the presence of Ni2+ [Costantini MG, Pearlmutter AF: J Biol Chem 259:11739–11745, 1984]. We extended our investigation to determine the effects of Ni2+, (AVP), and AVP analogs on SPM protein phosphorylation. Ni2+ (5 mM) caused a dramatic reduction in phosphorylation of most SPM phosphoproteins. The most prominent protein which is phosphorylated in SPM has a molecular weight of 48 kilodaltons (KDa) and has been named B50 or F1; this protein shows altered phosphorylation in vitro in response to long‐term potentiation in vivo as well as changes induced by exposure of SPM to ACTH (1–24), dopamine, and somatostatin. AVP and related peptides reduced phosphorylation of this presynaptic phosphoprotein in the following order of potency: AVP = oxytocin >DG‐AVP>dDAVP> d(CH2)5Tyr(Me) AVP = [pGlu4, Cyt6]AVP‐(4–9). Except for the pressor antagonist d(CH2)5Tyr(Me)AVP, this corresponds to their relative efficacy in displacing 3H‐AVP from high‐affinity specific binding sites on rat hippocampal synaptic membranes. Ni2+ did not alter the degree of inhibition caused by the peptides. When SPM were treated with AVP after the attainment of maximum 32P incorporation, AVP inhibited dephosphorylation over a 30‐min period. Our results show that AVP can alter both phosphorylation and dephosphorylation of hippocampal SPM phosphoproteins in vitro; the direction of these effects depends upon experimental conditions. Since B50/F1 is known to be a substrate for protein kinase C, AVP may act by inhibition of protein kinase C activity, either directly or indirectly.
Intracellular acetylcholinesterase of adult rat myofibers is more concentrated in endplate than non‐endplate regions
Authors: Donoso J. A. , Stiles J. R. , Fernandez H. L. 
Published: January 2005

AbstractThe intracellular distribution of acetylcholinesterase (AChE) was determined in adult rat anterior gracilis muscles. Echothiophate iodide (ECHO), a water‐soluble cholinesterase inhibitor, was applied to muscles in situ to eliminate extracellular and/or extracellularly oriented enzyme. Control and ECHO‐treated muscles were either cut into 1‐mm segments and assayed for AChE activity or cytochemically stained for AChE. Subsequent analysis by light and electron microscopy showed that the AChE stain inside myofibers was highly localized and clearly visible only in the zone immediately underlying the point of nerve‐muscle contact. Biochemical assay of muscle segments showed intracellular AChE to be most highly concentrated in regions containing large numbers of endplates (approximately twice the activity of endplate‐free areas). Since such “endplate‐rich” segments are in fact mostly extra‐synaptic tissue, we conclude that intracellular AChE of adult rat gracilis myofibers, although present along the length of the cell, is more than two times as concentrated in sub‐synaptic areas as compared to extra‐synaptic areas. This result must be carefully considered when attempting to identify “endplate‐specific” AChE activity of mammalian muscle, and further points to the importance of neural influences on AChE metabolism/regulation.
Acidic phospholipids, diacylglycerols, and free fatty acids in gerbil brain: A comparison of ischemic changes resulting from carotid ligation and decapitation
Authors: Huang S. F.‐L. , Sun G. Y. 
Published: January 2005

AbstractThe levels of brain acidic phospholipids (poly‐PI, PI, PA, and PS), DG, and FFA and their acyl group profiles were determined after induction of ischemia in gerbils by ligation of the common carotid arteries and decapitation. Ischemia induced by both procedures resulted in a significant decrease in poly‐PI (20% for 1‐min decapitation and 1‐min ligation). Except for a 16% increase in PI in the 5‐min decapitation group, no apparent change was found in other phospholipids after either ischemic condition. The level of DG was increased one‐ and threefold after 1 and 5 min, respectively, of decapitative ischemic treatment. Ligation of the carotid arteries for 1 min resulted also in a onefold increase in the DG level. The decapitative model resulted in a one‐ and fivefold increase in FFA level (with respect to 1 and 5 min, respectively), whereas ligation for 1 min resulted in an increase of 42% of the FFA. The acyl groups of poly‐PI and PI in the control gerbil brain are enriched in 18:0 and 20:4, but those of DG, FFA, and PA have a higher proportion of 16:0 besides 18:0 and 20:4. However, a preferential increase in the proportion of 18:0 and 20:4 was shown for the DG and FFA in both types of ischemic treatments. It is concluded from the results that both models of ischemic treatment elicit a similar decrease in poly‐PI and increase in DG, but differ in the amount of FFA release. The higher level of FFA release in the decapitative model suggests that other biochemical mechanisms may be activated to cause the additional release.
Cerebellum plus locus coeruleus in tissue culture II: Development and metabolism of catecholamines
Authors: Woodward W. R. , Seil F. J. , Hammerstad J. P. 
Published: January 2005

AbstractIn contrast to locus coeruleus neurons in vivo, dopamine was the predominant catecholamine synthesized, stored, and released by neonatal mouse locus coeruleus cultures which included target cerebellar tissue, and norepinephrine was present in these cultures only at very low levels. Developmentally, norepinephrine increased slightly in the explants during the first 4 days in vitro and declined thereafter to barely detectable levels, whereas dopamine began to rise after 4 days and reached maximal levels by 7 days. Dopamine β‐hydroxylase was present in these cultures throughout maturation. These results suggest that the high ratio of dopamine to norepinephrine in locus coeruleus cultures cannot be attributed to the absence of appropriate target tissue or to a lack of the enzyme, dopamine β‐hydroxylase.
Glycosaminoglycan composition of electric organ basement membranes
Authors: Inestrosa N. C. , Nader H. B. , Garrido J. , Sampaio L. O. , Brandan E. , Dietrich C. P. 
Published: January 2005

AbstractThe basement membranes of the innervated surface of the electric organ of Discopyge tschudii present a high concentration of mucopolysaccharides as revealed by intense ruthenium red‐positive reaction. Glycosaminoglycans (GAGs) were isolated and characterized from these pure basement membranes by using a combination of agarose gel electrophoresis and enzymatic degradation with specific enzymes. The isolated basement membrane showed a high concentration of GAGs (130 mg/g of dry tissue); of this amount 49% was hyaluronic acid, 24% was chondroitin‐6‐sulfate, 12% was heparan sulfate, and 14% was dermatan sulfate. Controlled digestion with heparinase and heparitinases I and II was used to study the structural features of the heparan sulfate. Four unsaturated disaccharide units were found in the heparan sulfate: disulfated, N‐sulfated, N‐acetylated, and N‐acetylated O‐sulfated disaccharides. The disaccharide units of the cholinergic heparan sulfate present a high amount of disulfated disaccharides and a low amount of N‐acetylated O‐sulfated disaccharides. The N‐sulfated disaccharides, in contrast to the N‐acetylated ones, were found through all the structure of the cholinergic heparan sulfate. Finally our work shows for the first time the presence of dermatan sulfate in the basal lamina of the electric organ.
Regulation of dihydropyridine calcium antagonist binding sites in the rat hippocampus following neurochemical lesions
Authors: Bolger G. T. , Basile A. S. , Janowsky A. J. , Paul S. M. , Skolnick P. 
Published: January 2005

AbstractThe effects of catecholaminergic, cholinergic, serotonergic, and glutaminergic terminal destruction and neurotransmitter depletion on [3H]nitrendipine binding to rat brain membranes were determined using the neurotoxins 6‐hydroxydopamine, 5,7‐dihydroxytryptamine, and kainic acid and the neurotransmitter‐depleting agent reserpine. Following intracisternal injection of 6‐hydroxydopamine there were time‐dependent increases (14–23%) in the density but not change in the affinity of hippocampal [3H]nitrendipine binding sites. 6‐Hydroxydopamine significantly increased [3H]nitrendipine binding in the hippocampus 4 and 10 days following injection. However, no significant change in binding was observed at 16 and 26 days. [3H]Nitrendipine binding in the cerebral cortex, striatum, cerebellum, and brain stem was unaffected by 6‐hydroxydopamine. Neither 5,7‐dihydroxytryptamine nor kainic acid affected [3H]nitrendipine binding in the hippocampus and cerebral cortex. Acute and chronic reserpinization also did not affect [3H]nitrendipine binding in the hippocampus and cerebral cortex. These results indicate that dihydropyridine calcium antagonist bindings sites in rat brain are subject to brain region‐specific regulation following neurochemical lesions and may be present in their largest densities on postsynaptic membranes.
Cation effects on taurine release from brain slices: Comparison to GABA
Authors: Oja S. S. , Kontro P. 
Published: January 2005

AbstractThe effects of cations on the spontaneous and potassium‐stimulated taurine release from mouse cerebral cortex slices were assessed with an emphasis on the as yet unestablished calcium dependence of the stimulated release. Spontaneous and stimulated GABA release was analyzed for comparison. A depolarizing concentration (50 mM) of potassium ions caused an approximately 3.5‐fold increase in taurine release and the omission of sodium a 6‐fold enhancement. GABA release was increased by the same stimuli about 20‐ and 34‐fold, respectively. Omission of calcium ions greatly enhanced basal taurine and GABA release when the medium was supplemented with the calcium chelator ethylenediaminetetraacetate. The potassium stimulation was then abolished, however, with taurine even more readily than with GABA. Magnesium and calcium ions had antagonistic effects on the stimulated release, more clearly with taurine than with GABA. Verapamil abolished the potassium stimulation of both taurine and GABA release, the latter being more sensitive. Although the stimulated taurine release was less in magnitude and had a slower time course than the GABA release, the results are not at variance with the possible neurotransmitter role of taurine.
The influence of muscle‐conditioned media on chick embryo brainstem neurons in culture
Authors: Heaton M. B. , Kemperman H. 
Published: January 2005

AbstractBrainstem pieces from the trigeminal region of the metencephalic basal plate of 10‐day chick embryos were dissociated and cultured in control conditions or in the presence of muscle‐conditioned medium (MCM). The MCM was derived from age‐matched target tissue relevant to this neuronal region (jaw musculature), from relevant target tissue of an age at which innervation would initially be taking place (4 days), and from nonrelevant target tissue also of an early stage (4‐day limb bud). Neuronal survival and differentiation was assessed daily, for 7 days. Survival and differentiation were significantly enhanced by the 4‐day jaw MCM compared to both the controls and the cultures grown with 10‐day jaw MCM and 4‐day limb MCM. These measures in the presence of 10‐day jaw MCM and 4‐day limb MCM did not differ, but surpassed that seen in control cultures. The results are compared to the more specific responsiveness seen in earlier (2‐day) neural tube cultures, and their relationship to in vivo regenerative nerve fiber outgrowth is considered.