bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biologic and radioimmunologic activity of cholecystokinin in regions of mammalian brains
Authors: Simon‐Assmann P. M. , Yazigi R. , Greeley G. H. , Rayford P. L. , Thompson J. C. 
Published: January 2005

AbstractThe distribution and heterogeneity of cholecystokinin (CCK) in different regions of the central nervous system (CNS) of 12 adult rats and six cows was determined by means of specific radioimmunoassays. In addition, the biologic activity of immunoreactive material was evaluated in a bioassay that used a rabbit gallbladder‐strip preparation. High amounts of immunochemically detectable CCK‐8 (20.2 ± 1.5 pmol/g) and CCK‐33 (33.7 ± 3.3 pmol/g) and of biologically active CCK were found in the telencephalon, although concentrations decreased progressively from the rostral to the caudal portions of the brain. The distribution and biologic activity of CCK was similar in rat and cow brain. Ratios of biologic to immunologic activity ranged from 1.0 to 8.0 and were higher for CCK‐8 than for CCK‐33. The results indicate that (1) CCK‐8 and CCK‐33 immunoreactivity are widely distributed throughout the CNS in a unique and differential manner; (2) CCK is biologically active in all the regions of the brain, with a pattern of distribution similar to that found with radioimmunoassay; (3) measurable bioactivity was equal to or greater than measurable immunoreactivity in all areas of the brain in rat and cow; and (4) CCK is present in tissues without significant species differences between rat and cow.
Activities of arginase, transamidinase, and ornithine aminotransferase in glia, neurons, and synaptosomes
Authors: Swamy M. , Shrivastaw K. P. , Prasad M. S. K. , Sadasivudu B. 
Published: January 2005

AbstractThe regional, cellular, and subcellular distribution of some enzymes of the urea cycle in brain is not clearly known. Glia, neurons, and synaptosomes have been prepared from rat cerebral cortex and arginase (EC 3.5.3.1), transamidinase (EC 2.1.4.1), and ornithine aminotransferase (EC 2.6.1.13) have been estimated in order to understand the metabolic and functional role of these enzymes. It has been observed that arginase is predominantly localized in synaptosomes and neurons. The ornithine aminotransferase was found to be high in glial cells and very high in synaptosomes (higher than arginase). Transamidinase was mostly localized in glial cells. The implication of these results has been discussed in relation to a possible role of ornithine acting as a precursor of glutamate in glutametargic nerve endings and its possible participation in the glutamate‐glutamine cycle.
In bovine brain extracts, RNAs are active factors that stimulate the proliferation of chick neuroblasts in culture
Authors: Barakat I. , Sensenbrenner M. , Labourdette G. 
Published: January 2005

AbstractExtract was prepared from bovine brain by treatment with chloroform‐methanol, drying of the precipitate, and successive extractions of the powder with Tris buffer. Influence of this extract on neuroblast proliferation in culture was tested. Neuroblast cultures were prepared from brain hemispheres of 6‐day‐old chick embryos. Cell proliferation was quantified by incorporation of 3‐thymidine. The brain extract was able to stimulate the proliferation of the neuroblasts in culture. In order to purify the factor responsible of this effect, the brain extract was subjected to diethylaminoethyl (ENAE)‐cellulose chromatography and gel filtrations. By UV spectrography and destruction of the activity with RNAase and KOH, it was shown that in the extract RNAs are responsible for at least a part of the effect on the proliferation of neuroblasts in culture. Brain RNA is not specific for this effect, since mouse ribosomal RNA was also active. The effect could be actually elicited by some nucleotides.
A comparative study of L[3H]‐glutamate and L[3H]‐cysteine sulfinate binding sites in subcellular fractions of rat brain
Authors: Recasens M. , Saadoun F. , Baudry M. , Maitre M. , Lynch G. 
Published: January 2005

AbstractA comparative study of the binding of L‐cysteine sulfinic acid (CSA) and L‐glutamic acid (GLU) to various subcellular fractions of membranes from rat brain was made. Kinetic parameters were determined in all fractions for both types of binding. The effects of membrane preincubation, freezing, and thawing were also examined. The GLU and CSA specific binding levels increased in medium‐density (C) and high‐density (D) synaptic membranes as compared to the crude mitochondrial/synaptosomal membranes (wP2). Freezing and thawing reduced CSA binding in all tested subcellular fractions. GLU binding is reduced in wP2, C, and D. Binding to the “light” synaptic membranes (B) was not significantly affected, suggesting the presence of two GLU sites. Kinetics of the GLU binding indicated that the temperature‐sensitive and ‐insensitive sites have Kd of 600 nM and 1,100/nM, respectively. Preincubation of fresh membranes conversely affected CSA and GLU binding to the various subcellular fractions, increasing CSA binding in wP2, B, C and decreasing it in D suggesting the existence of distinct sites for GLU and CSA. Preincubation of previously frozen membranes similarly modified CSA and GLU binding except in B fractions. CSA and GLU binding exhibited different pH sensitivities in both fresh and frozen membranes. These results indicate that multiple acid amino acid binding sites exist in membranes and that they can be differentiated according to their sensitivity to temperature. They also suggest the existence of distinct sites for CSA and GLU in fresh membranes, giving further support to the hypothesis that CSA may also serve a neurotransmitter role in the rat central nervous system.
Effects of lithium on [3H](–)quinuclidinyl benzilate ([3H](–)QNB) binding to rat brain muscarinic cholinergic receptors
Authors: Hruska R. E. , Ludmer L. M. , Pert A. , Bunney W. E. 
Published: January 2005

AbstractAddition of lithium in vitro inhibited the binding of [3H](–)QNB to muscarinic cholinergic receptors of homogenates of tissue prepared from the striatum, cortex, and hippocampus of rat brain. Chronic in vivo exposure of rats to lithium in their food produced serum levels of lithium comparable to therapeutic levels. After in vivo exposure, the tissue homogenates prepared from these rats had an apparent decrease in receptor density in the three brain areas. However, if the tissue homogenates were washed twice, before addition to the assays, no differences in binding were detectable. Similar effects on unwashed and washed tissue homogenates can be demonstrated after in vivo exposure to lithium. Therefore, the apparent decrease in binding after in vivo lithium treatment is probably due to lithium retained in the tissue. No permanent alterations in the muscarinic receptor characteristics were measurable after the removal of the lithium. Nevertheless, in vivo interactions at muscarinic receptors may be important under conditions when therapeutic levels of lithium are present.
Effect of guanidinoethane sulfonate on taurine uptake by rat retina
Authors: Quesada O. , Huxtable R. J. , Pasantes‐Morales H. 
Published: January 2005

AbstractGuanidinoethane sulfonate (GES) markedly decreased 3H‐taurine accumulated in the retina by the high‐affinity uptake process. The effect of GES was dosedependent. Analysis of the kinetics of GES effect revealed that it is a competitive inhibitor. The uptake of taurine by GES was less affected in rat cerebral cortex slices, where the inhibition by 1 mM GES was only 28%. Taurine accumulation by tissues of rats treated with GES (0.1% and 1% in the drinking water) was found to be particularly decreased in the retina, although accumulation by heart and liver was also affected by the higher dose. Taurine uptake by cerebellum and cerebral cortex slices was unaffected by GES. Treatment of rats with GES is known to produce an alteration in the structure and function of the retina, but apparently not in other organs. We discuss whether the marked effect of GES on taurine transport by the retina is related to the deleterious effect of the inhibitor in this organ.
Taurine‐ and penicillin‐induced epileptic activity
Authors: Alvarez A. , de Cotte D. Marcano , Pérez J. R. , Requena M. A. , Vallecalle E. , Drujan B. D. 
Published: January 2005

AbstractThe present study has been performed to investigate the effect of i.v. administration of taurine on the electrical activity of the epileptogenic focus induced by penicillin applied to the right sensory motor cortex of adult rats. Taurine (100 mg/kg body weight) was administered 15, 30, 60, and 120 min before the application of penicillin. The EEG was unipolarly recorded by means of electrodes applied to the pia. Taurine caused a decrease of the frequency as well as the spike amplitude of epileptic discharge. The spread of epileptogenic foci to the opposite hemisphere was retarded when compared to that of control animals. The maximal antiepileptic effect of taurine was observed when the amino acid was administered 30–60 min previous to penicillin. It is suggested that high concentrations of taurine in the brain might be necessary to inhibit the epileptic activity.
Investigations on myelinogenesis in vitro: Regulation of 5′‐nucleotidase activity by thyroid hormone in cultures of dissociated cells from embryonic mouse brain
Authors: Shanker G. , Rao G. S. , Pieringer R. A. 
Published: January 2005

AbstractThe developmental pattern of the myelin‐associated 5′‐nucleotidase and its regulation by L‐3,3′,5,‐triiodothyronine (T3) have been demonstrated in a culture system of cells dissociated from embryonic mouse brain. Hypothyroid calf serum containing low levels of T3 (31 ng/100 ml), and thyroxine, T4 (< 1 μg/ml), was used in the culture medium in place of normal calf serum (T3, 103 ng/100ml; T4, 5.7 μg/ml) to render the cultures responsive to exogenously added T3. By means of T3 supplementation, the lower levels of enzyme activity observed in the cultures grown in the presence of hypothyroid calf‐serum containing medium could be restored to a considerable extent although not completely to normal values. Halfmaximal stimulatory effect was obtained at 3.9 × 10−8 M T3 concentration. Among the various substrates tested, 5′‐AMP, 5′‐UMP and 5′‐CMP were equally good, while 5′‐GMP yielded approximately half the activity.
Fatty acid and long‐chain base composition of gangliosides isolated from adult human brain
Authors: Ando S. , Yu R. K. 
Published: January 2005

AbstractA series of major and minor ganglioside species were isolated from a single human adult brain and analyzed for their lipophlic composition. Hematosides, GM3 and GD3, each showing double bands on thin‐layer chromatograms, were separated into the upper band and lower band fractions to be analyzed for the heterogeneity of their ceramide moieties. The upper band fractions of GM3 and GD3 were found to contain relatively high amounts of longer‐chain fatty acids (C20C26), whereas the lower band fractions contained high amounts of shorterchain fatty acids (C16C18). Compared to other gangliosides which contain hexosamine, the two hematosides contained a smaller proportion of stearic acid. The proportion of 4‐eicosasphingenine was found to increase with increasing sialic acid content in gangliosides. These findings suggest that, in the biosynthesis of various gangliosides, N‐acetylhexosamine is preferentially transferred to hematosides rich in stearic acid, and sialic acid residues are preferentially transfered to 4‐eicosasphingenine‐containing species.
Studies on bioactive gangliosides: II. Requirement of ganglioside GD1a for prolonged GQ1b‐driven nerve growth promotion in neuroblastoma cell lines
Authors: Arita M. , Tsuji S. , Omatsu M. , Nagai Y. 
Published: January 2005

AbstractThe novel effects of gangliosides from human brain on the number of nuclei of nerve cells and neurite outgrowth were studied in cultures of human neuroblastoma cell lines GOTO and NB‐1. Ganglioside GQ1b at a nanomolar level stimulated cell proliferation and neurite outgrowth during culture for 24 hours, as reported previously [J Biochem 94: 303–306, 1983]. Although the neurite promoting activity of GQ1b was similar to those of total human brain gangliosides (GS) and nerve growth factor (NGF), its activity on cell proliferation did not persist on longer culture; that is, the number of GQ1b‐treated cells rapidly decreased to the control level during culture for 48 or 72 hours. In contrast, on treatment with GS or NGF, the number of cell nuclei increased continuously during prolonged culture. These results showed that either some other molecular species of ganglioside(s) than GQlb or other substances such as proteins present in the GS fraction were responsible for the long‐term activity. Studies on the GS fraction after its treatment with proteases and neuraminidases revealed that ganglioside GDla (20 ng/ml) had the ability to prolong the activity of GQlb. Namely, GQlb and GDla gangliosides cooperated in maintaining the number of nuclei in long‐term cultures of neuroblastoma cell lines.
Interaction of GM1 ganglioside with PC12 pheochromocytoma cells: Serum‐ and NGF‐dependent effects on neuritic growth (and proliferation)
Authors: Katoh‐Semba R. , Skaper S. D. , Varon S. 
Published: January 2005

AbstractThe effects of ganglioside GM1 on proliferation and neuritic growth of PC12 pheochromocytoma cells were studied in the presence and absence of nerve growth factor (NGF). In the absence of NGF, but not in its presence, a decrease in the total number of PC12 cells was first observed after 4–6 days of culture with 10−6 M GM1 in 0.1% fetal calf serum, and with 10−3 M GM1 on 10% serum. NGF, with or without GM1, limits cell growth to the first 4–6 days. GM1 enhanced neuritic recruitment with serum concentrations of 0.3% or more. Optimal neurite response varied from 10−6 M GM1 with 0.3% serum to 10−4 M GM1 with 10% serum. The influence of GM1 on neurites became more pronounced with increasing serum concentrations, becoming maximal with 1% or greater serum. Serum exhibited a concentration‐dependent inhibitory influence (lag) on NGF‐induced neuritic recruitment, which was abolished by GM1. Rates of neuritic recruitment following the lag were unaffected by GM1, while showing an inverse correlation with serum concentrations of 0.1–0.5%. Serum may delay the NGF‐induced neuritic recruitment of PC12 cells by two independent mechanisms. These results suggest that GM1, in some manner, prevents the serum‐induced delay in the onset of neuritic recruitment, rather than stimulating the rate at which it precedes.
Does the interstitial nucleus of Cajal project to the hypoglossal nucleus in the rat?
Authors: Aldes L. D. , Boone T. B. 
Published: January 2005

AbstractThe present study sought to determine whether or not the hypoglossal nucleus receives direct afferent projections from the interstitial nucleus of Cajal. Results from anterograde and retrograde labeling experiments in the rat indicated that while projections from the interstitial nucleus of Cajal do not terminate within the hypoglossal nucleus, they do so among a small group of neurons located ventrolateral to the hypoglossal nucleus, the nucleus of Roller. These findings are discussed in relation to orolingual motor behavior.
Kinetics of GTP‐modulation of adenylate cyclase in gerbil cerebral cortex after bilateral ischemia
Authors: Taylor M. D. , Palmer G. C. , Callahan A. S. 
Published: January 2005

AbstractChanges in the sensitivity of adenylate cyclase and steady‐state levels of cyclic AMP (adenosine 3′,5′‐monophosphate) occur in mammalian brain during ischemic episodes. In our previous investigation with the gerbil model of bilateral ischemia there was an indication that ischemic conditions produced an enhancement of GTP sensitivity of adenylate cyclase within the cerebral cortex. The present study employed a kinetic analysis to evaluate further the role of this GTP modulation of adenylate cyclase in the gerbil frontal cortex during periods of bilateral ischemia and recirculation. In general, after either 15‐min (with or without 15‐min reflow) or 60‐min ischemia the Vmax to GTP (alone or with dopamine and norepinephrine) was increased. Under these conditions the ED50 for half‐maximal enzyme activation was decreased, indicating a greater affinity of the transducer site for GTP during ischemia. However, if irreversible 60‐min ischemia was followed by 15‐min reflow the enzyme responses to GTP were now absent. An unexpected observation showed that the ED50 for GTP activation of cortical adenylate cyclase was likewise attenuated when sham‐operated animals were compared to normal gerbils.
A quantitative study of growth cone filopodial extension
Authors: Argiro V. , Bunge M.B. , Johnson M.I. 
Published: January 2005

AbstractThe extension of filopodia from growth cones of regenerating neurites from rat superior cervical ganglion neurons in tissue culture was studied. Cultures were grown on a thin layer of fibrous collagen and maintained in a medium containing serum and nerve growth factor. Time‐lapse cinematography and computer‐assisted morphometry were used to observe and measure the kinetics of extension of individual filopodia. Filopodia extended from the growth cone margin, trailing neurite, or from each other. Frequently, extension was preceded by the appearance at the cone margin of a nodule of cytoplasm which appeared dense in phasecontrast optics. Branch points between adjacent extending filopodia remained fixed with respect to the growth cone while the filopodia lengthened. The rate of extension was maximum just after initiation (0.12 ± 0.4 μm/sec; mean ± SD; n = 36) and declined thereafter until the filopodium collapsed. This initial rate of extension was directly correlated with the eventual length of the filopodium (r = 0.67). Filopodia of growth cones arising from embryonic neurons exhibited higher initial extension rates (range: 0.07 to 0.20 μm/sec; mean = 0.13 μm/sec) than those of postnatal neurons (range: 0.01 to 0.13 μm/sec; mean = 0.09 μm/sec). These data are discussed in relation to a model proposed by Tilney and Inoue [1982] for the extension, by distal addition of G‐actin to growing filaments, of another type of elongating process filled with microfilaments, the acrosomal process of Thyone sperm.
Sensory neurite growth cone guidance by substrate adsorbed nerve growth factor
Authors: Gundersen R.W. 
Published: January 2005

AbstractThe response of growth cones from embryonic chick dorsal root ganglia to a patterned substrate of adsorbed nerve growth factor (NGF) was studied. The patterned substrate presented growth cones with an adsorbed NGF pattern and NGF‐free substrate. NGF‐responsive growth cones from 7 and 9 day ganglia could not proceed onto NGF‐free substrate, reproducing the adsorbed NGF pattern. NGF‐unresponsive growth cones from 17 day ganglia did not display any preference for adsorbed NGF or NGF‐free substrata, which resulted in neurites not reproducing the adsorbed NGF pattern. Neurite outgrowth from NGF responsive 7‐day ganglia onto a patterned NGF substrate, in NGF‐containing medium, was radially symmetrical, exhibiting no growth cone response to the patterned NGF substrate. The lack of NGF‐responsive growth cone extension onto NGF‐free substrate indicates that NGF is a requirement for neurite elongation. If NGF is withdrawn from growth cones by microperfusion, neurite elongation ceases. Thus, an adsorbed pattern of NGF may be duplicated because growth cones are not able to extend onto NGF‐free substrate, since NGF is a requirement for neurite elongation. These results indicate that substrate adsorbed NGF can support neurite formation and elongation as well as guide the direction of neurite elongation.
Electrical and ionic controls of tissue cell locomotion in DC electric fields
Authors: Cooper M.S. , Schliwa M. 
Published: January 2005

AbstractThe motility of fish epidermal cells (keratocytes) was examined in the presence and absence of DC electric fields. In fields of 0.5–15 V/cm, single epidermal cells, cell clusters, and cell sheets migrate toward the cathode. Cell clusters and sheets break apart into single migratory cells in the upper range of these field strengths. During locomotion, keratocytes extend broad lamellipodia, which contain a pervasive actomyosin network. The lamellipodial extension and locomotion of keratocytes are reversiby inhibited by a variety of calcium channel antagonists, whereas thir motility is unaffected by hyperpolarizing and depolarizing (low and high K+) media. Microtubule disassembly has no effect on cell morphology, motility or the ability of the cells to be guided by a DC electric field. Using these results, the role that membrane‐regulated Ca2+ influx may play in generating cytoskeletal and protrusive activity in keratocytes and other cells is discussed in some detail. Mechanisms by which an external electric field may bias transmembrane ion fluxes and thereby control cell locomotion are also examined.
Binding and internalization of lysosomal enzymes by primary cultures of rat glia
Authors: Hill D. F. , Bullock P. N. , Chiappelli F. , Rome L. H. 
Published: January 2005

AbstractHighly purified cultures of rat astrocytes and oligodendrocytes were examined for their ability to bind and internalize lysosomal enzymes. Astrocytes displayed a saturable uptake to β‐glucosidase and β‐galactosidase. The uptake was specifically inhibited by mannose‐6‐phosphate but not by several other sugars or sugar phosphates, indicating that the process was mediated by mannose‐6‐phosphate receptors. When cells were allowed to take up 125I‐β‐glucosidase for 1 hr at 37°C and subcellular organelles were isolated, the enzyme was shown to comigrate with a lysosomal organelle marker enzyme, suggesting that the enzyme was targeted to lysosomal. Astrocyte receptors were probed directly by binding of 125I labeled β‐glucosidase to astrocyte membranes at 4 °C. Binding was saturable and competitively inhibited by mannose‐6‐phosphate. In contrase to the astrocytes, cultured oligodendrocytes showed no specific binding or uptake of the lysosomal enzymes. Immunocytochemical staining of mixed glial cultures supported the biochemical data; only the astrocytes stained positive with anti‐mannose‐6‐phosphate receptor antibodies.
Response to gallamine: An indicator of diminished neuromuscular function in experimental autoimmune myasthenia gravis
Authors: Hinman C. L. , Dambach G. E. , Hudson R. A. , Rauch H. C. 
Published: January 2005

AbstractA test for diminished neuromuscular function in animals with experimental autoimmune myasthenia gravis is described. Within minutes following an injection of gallamine triethiodide, mice exhibit a dramatic yet transient response which is dose‐dependent. Mice previously inoculated with acetylcholine receptor are approximately twice as sensitive to gallamine as normal mice. Positive results have been found in over 80% of receptor‐inoculated BALB/c mice and in 94% of C57B1/6 mice.
Alteration of seizures resulting from pinealectomy in the rat after neonatal treatment with 6‐hydroxydopamine
Authors: Stockmeier C. A. , Larsen B. R. , Blask D. E. 
Published: January 2005

AbstractConvulsions from combined pinealectomy and parathyroidectomy were examined in rats treated as neonates with 6‐hydroxydopamine (6‐OHDA). Injection of 6‐OHDA caused a significant reduction in the average latency to onset of clonictonic convulsions. Moreover, of the 6‐OHDA‐treated rats which convulsed, nearly half of them died during a seizure. In sham‐pinealectornized rats, neonatal treatment with 6‐OHDA reduced norepinephrine (NE) and increased dopamine levels in the forebrain while brainstem levels of NE were increased. Pretreatment with desmethylimipramine reversed the effects of 6‐OHDA on convulsions and catecholamine levels. The results indicate that catecholamine lesions with 6‐OHDA exacerbate convulsions from pinealectomy.