bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigations on myelination in vitro. III. Ultrastructural, biochemical, and immunohistochemical studies in cultures of dissociated brain cells from embryonic mice
Authors: Sarliéve L. L. , Delaunoy J. P. , Dierich A. , Ebel A. , Fabre M. , Mandel P. , Rebel G. , Vincendon G. , Wintzerith M. , Yusufi A. N. K. 
Published: January 2005

AbstractCerebral hemispheres of 14‐ to 15‐day‐old mouse embryos were dissociated mechanically into single cells and cultured in polylysine‐coated plastic flasks. The succession of changes and the identification of cell populations have been studied by transmission electron microscopy (TEM). Four distinct cell types can be clearly defined. Neuroblasts, oligodendroblasts, and astroblasts were used to denote embryonic states of neurons, oligodendrocytes, and astrocytes. Cell populations were: (1) neuroblasts; (2) astroblasts, either growing on the surface of the flasks and forming a basal layer of epithelioid cells or scattered at the surface of the bed layer; (3) oligodendroblasts, characterized by a high nucleocytoplasmic ratio and resting on top of the bed layer; (4) macrophages. Incorporation of [3H]thymidine into cells at different days in culture (DIC) delineated at least three periods of DNA synthesis (from 1 to 6, from 10 to 20, and from 25 to 60 DIC). High cell RNA/DNA and protein/DNA ratios indicated an increase in the cytoplasmic mass. Guanylate cyclase (EC 4.6.1.2; GC) and adenylate cyclase (EC 4.6.1.1; AC) activities and the ratio AC/GC also agreed with the existence of different periods in culture, but the yin yang hypothesis (postulated by Goldberg et al, 1975) was only partially confirmed. Concerning membrane constituents, the evolution of the pattern of the major gangliosides showed a phase from 1 to 20 DIC which was characterized during the first half of this period by a high percentage of tri‐ and tetra‐sialogangliosides, thereby confirming the presence of well differentiated neurons. Choline acetyltransferase (EC 2.3.1.6; ChAc), acetylcholinesterase (EC 3.1.1.7; AChE), and [3H]muscimol binding (indicative of GABA‐receptors) supported this conclusion. Another phase from 20 to 60 DIC showed a relatively higher content of GM3 and GD3 of the disialogangliosides GD1a and GD1b. These data favor a glial origin of the cells, also demonstrated by TEM and by immunohistochemistry with anti‐glial fibrillary acidic protein (anti‐GFAP) and anti‐carbonic anhydrase isoenzyme II (anti‐CAII; EC 4.2.1.1) sera.Ultrastructural, biochemical, and immunohistochemical data are in agreement with the existence of successive and different periods of cell proliferation and differentiation which have been defined as: (1) mainly neuronal from 1 to 12 DIC; (2) astroglial and oligodendroglial between 10 and 20 DIC, and (3) possibly microglial from 25 to 40 DIC. This surface‐adhering primary culture system should significantly enhance efforts to examine the roles played by hormones or other effectors in the regulation of myelination.
Uptake of glutamate, GABA, and glutamine into a predominatly GABA‐ergic and a predominantly glutamatergic nerve cell population in culture
Authors: Yu Albert C. H. , Hertz Leif 
Published: January 2005

AbstractUptake kinetics for glutamate, GABA, and glutamine were determined in primary cultures of cerebral neurons, a predominatly GABA‐ergic cell population, and of cerebellar granule cells, a predominantly glutamatergic cell population. A specially high Vmax for GABA uptake into the former and for glutamate uptake into the latter cells suggests that considerable amounts of released transmitters may be reaccumulated into appropriate nerve terminals. Nervertheless, the glutamate uptake into the cerebellar granule cells was less intense than that previously observed into corresponding cultures of astrocytes, whereas GABA was accumulated more intensely into neurons than into astrocytes. This suggests that especially glutamatergic neurons may be depleted for their transmitter by accumulation into adjacent astrocytes. If a glutamine flow from astrocytes back to neurons served the purpose of balancing this transfer, it should be expected that glutamine accumulation was more intense in the glutamatergic than in the GABA‐ergic cell population. This was not the case, suggesting that such a glutamate–glutamine cycle may not be operating to a major extent.
Picrotoxin action on the receptive fields of the cat sensorimotor cortex neurons
Authors: Batuev A. S. , Alexandrov A. A. , Scheynikov N. A. 
Published: January 2005

AbstractThe receptive fields of the sensorimotor cortex neurons identified by electrocutaneous stimulation were modified by microelectrophoretically applied picrotoxin which is known to reduce inhibition. A relatively short application of picrotoxin (90 nA during 3–6 min) markedly increased the size of the neuronal receptive fields in the sensorimotor cortex. Control application of glutamate showed that additional depolarization did not affect receptive fields of the spontaneously active units. Our results together with other work in this field further support the hypothesis that inhibitory processes play a major role in forming functional properties of the cerebral cortex neurons.
A neurotrophic factor (NTF) released from primary glial cultures supports survival and fiber outgrowth of cultured hippocampal neurons
Authors: Müller Hans Werner , Seifert Wilfried 
Published: January 2005

AbstractA nearly pure neuronal culture from embryonic rat brain (hippocampus) has been established in order to observe individual neurons during their in vitro development. This neuronal culture has been used as a test system for a neurotrophic factor (NTF) which is released into a serum‐free defined medium, presumably by astrocytes, the dominant cell type in a primary glial culture from rat brain. NTF is essential for the development of the hippocampal neurons in cell culture. The number of neurons responding to NTF by neurite extension is highly dependent on the concentration of the factor in the culture medium. The amount of factor in serum‐free glial conditioned medium can be estimated in a rapid (20‐hour) bioassay.
Nerve growth factor‐induced stimulation of α‐aminoisobutyric acid uptake in PC 12 cells: Evaluation of its biological significance
Authors: Kedes Dean H. , Gunning Peter W. , Shooter Eric M. 
Published: January 2005

AbstractIn the clonal PC12 pheochromocytoma cell line, the observed effects of nerve growth factor (NGF) on the uptake rates of α‐aminoisobutyric acid (AIB) depend upon the assay conditions employed. In orthodox uptake assays calling for serum removal prior to the addition of AIB, 50 ng/ml NGF causes a stimulation of uptake of 62% after 40 minutes and 46% after 24‐hours exposure. However, serum stimulates AIB uptake to a similar extent and the effects of serum and NGF are not additive. An uptake assay which directly measures the AIB uptake experienced by PC12 cells undergoing NGF‐induced morphological differentiation was therefore employed. When compared with control cells growing in serum‐containing medium, NGF‐induced differentiating PC12 calls experience (1) only a transient and modest increase in AIB uptake, and (2) a significant long‐term decrease in AIB uptake under conditions optimal for differentiation. It is concluded that NGF‐directed neurite outgrowth is not mediated by NGF effects on amino acid uptake via the A‐system.
Nerve growth factor effects and receptors in cultured human neuroblastoma cell lines
Authors: Sonnenfeld Kenneth H. , Ishii Douglas N. 
Published: January 2005

AbstractWe studied the effects of nerve growth factor (NGF) to determine whether neuroblastoma (NB) cells share the pattern of altered response to growth regulatory factors shown by various malignant transformed cells. NGF induces neurite outgrowth, arrests growth, and enhances survival in normal neurons and in the rat pheochromocytoma, a tumor cell closely related to NB. With respect to neurite outgrowth, lines SK‐N‐SH, SH‐SY5Y, LA‐N‐5, and CHP‐126 were sensitive, IMR‐32 was resistant, and SH‐EP1, SK‐N‐MC, MC‐IXC, CHP‐100, and CHP‐134 were unresponsive. Conditioned media from unresponsive cells did not inhibit response in sensitive cells. Unexpectedly, NGF neither reduced the growth rate nor enhanced survival in any NB cell line. Conditioned medium from all NB cell lines enhanced 125I‐NGF binding in embryonic sensory cells. Regulation of growth rate and neurite outgrowth, then, are separable. A fundamental defect in NB may be the acquisition of a capacity for growth and survival independent of NGF. 125I‐NGF was bound to both Fast and Slow receptors in MC‐IXC cells, but only to Slow receptors in NGF‐responsive SH‐SY5Y and LA‐N‐5 cells, showing Fast receptors are not required for neurite outgrowth. Independence from NGF‐regulated growth and survival is unexplainable by an absence of NGF receptors.
Modification of membrane‐bound proteins of the hippocampus and entorhinal cortex by change in behavior in rats
Authors: Hydén Holger , Lange Paul W. 
Published: January 2005

AbstractRats were trained in an instrumental task for 2 × 25 min during 1 day and 4 days and compared with active controls with respect to membrane‐bound proteins solubilized by chloral hydrate and fractionated on polyacrylamide gels. Then 30‐μg samples of the hippocampus and entorhinal cortex were labeled by 14C‐and 3H‐valine. The distribution of the stained electrophoretogram was recorded by microdensitometry. The results show that the 1‐day training induced an increased synthesis of a membrane protein fraction of 50,000 mol wt already present in the brain membrane proteins of active controls. Training for 4 days resulted in an overall stimulation of the hippocampal membrane protein fractions, especially in the higher‐molecular‐weight range. The entorhinal cortex showed two stimulated membrane protein fractions, 50,000 and 120,000 mol wt. Together with previous studies, this study makes it probable that training to establish a new behavior induces a modulation of both soluble and membrane‐bound protein patterns in the hippocampus and the entorhinal cortex with a time phase retardation for the latter.
Dose effects of morphine on the spontaneous unit activity recorded from the thalamus, hypothalamus, septum, hippocampus, reticular formation, central gray, and caudate nucleus
Authors: Dafny N. , Burks T. F. , Bergmann F. 
Published: January 2005

AbstractSpontaneous activity was recorded from 652 units in 8 subcortical structures of unanesthetized rats. Recordings were obtained in central gray, mesencephalic reticular formation, parafasciculus thalami, caudate nucleus, anterior and ventro‐ medial hypothalamus, lateral septum, and dorsal hippocampus. Eighty recordings were obtained from untreated animals and 80 from saline‐injected controls, none of which showed any significant changes of unit activity during the 4‐ 5‐hr observation period. The effect of morphine, given in 5 incremental doses from 0.5 to 30.0 mg/kg ip, was followed in 492 units.Morphine enhanced or depressed spontaneous discharge rates, or caused biphasic effects, ie enhancement alternating with depression and vice versa. Naloxone induced increase in firing after either effect of morphine, or reduced spontaneous activity after morphineinduced increases. However, when morphine reduced neuronal discharges, naloxone never caused further depression.In 86 units, morphine at any dosage failed to alter neuronal activity, but in 54 of these units naloxone nevertheless induced alterations in firing rates.The pattern of responses to morphine differed between all 8 brain regions examined and was characteristic for each individual structure. This is the first systematic study describing the dose‐response characteristics of morphine in 8 brain sites recorded simultaneously. Furthermore, it utilized freely behaving animals without the interference of anesthetics, which are themselves known to interact with opiates. The variety of response patterns seen supports the neuro pharmacological evidence for multiple opiate receptors or multiple sites of opiate action.
Studies on acetylcholinesterase and gamma‐glutamyltranspeptidase in mouse brain in ammonia toxicity
Authors: Sadasivudu B. , Murthy C. R. K. , Rao G. N. , Swamy M. 
Published: January 2005

AbstractShort‐ and long‐term ammonia toxicity was induced in mice by intraperitoneal injection, respectively, of single and six doses of 0.6 mM ammonium acetate per 100 g of body weight. The animals were sacrificed half an hour after either the single injection or after the last injection of six doses. Under these experimental conditions the ammonia levels were found to be elevated twofold in cerebral cortex, brain stem, and basal ganglia after the administration of a single dose of ammonium acetate. A fourfold increase in the content of ammonia was observed in cerebral cortex, brain stem, and basal ganglia after six injections. An elevation in the activity of pseudocholinesterase (enzyme localized in brain capillaries and dial cells) in all the above four regions resulted as a short‐term effect of ammonia toxicity. True acetylcholinesterase was found to be elevated in all the four regions in short‐term and in long‐term ammonia toxicity. Gamma‐glutamyltranspeptidase (GGTP), another enzyme localized in cerebral capillaries and glial cells, was found to be depressed in all the regions of the brain in both short‐ and long‐term ammonia toxicity. The implications of these results are discussed in relation to glial cell function.
Interactions between amino acid neurotransmitters and flurazepam in the neocortex of unanesthetized rats
Authors: Tancredi V. , Frank C. , Brancati A. , Avoli M. , White P. 
Published: January 2005

AbstractThe effects induced by the benzodiazepine flurazepam (FLU) upon neuronal responses to glutamic acid (GLUT), γ‐aminobutyric acid (GABA), and glycine (GLY) were studied in the cortex of unanesthetized rats using single‐unit extracellular recordings in conjunction with iontophoretic techniques. The application of FLU (5‐20 nA) did not affect excitatory responses to GLUT, but the spontaneous firing rate was depressed by equivalent doses of this benzodiazepine. A selective increase of GABA, but not of GLY‐induced responses was seen when either low currents (5–10 nA) of FLU or GLUT driving currents were used to study the neuronal responses of the inhibitory amino acids upon steady neuronal firing. Our data demonstrate that in unanesthetized animals FLU does not affect GLUT‐ induced effects while it selectively increases GABA‐mediated inhibition.
Increased phosphorylation of nuclear protein in myonuclei isolated from denervated skeletal muscle
Authors: Held Irene R. 
Published: January 2005

AbstractThe slow‐twitch soleus muscle of the rat hindlimb was denervated by cutting the sciatic nerve in the midthigh on one side. A sham operation was performed on the contralateral side to provide a control soleus muscle. At 24, 48, 72, and 120 hours after these surgical procedures, the animals were sacrificed and the nuclei which were isolated from these muscles incubated in a phosphorylating medium containing [γ32P]ATP. At the 48 hour denervation period only, the in vitro phosphorylation of TCA‐precipitable nuclear proteins was significantly increased compared to control values. Resolution of the SDS‐solubilized nuclear proteins by polyacry‐lamide gel electrophoresis revealed that the increased phosphorylation was more marked in some phosphoproteins than others. The significance of these early denervation changes are discussed with respect to increases in the activities of the nuclear RNA polymerases and changes in the phosphorylation of cytosolic protein.
Regional difference in density of monoamine‐accumulating cells of carp and catfish retinas
Authors: Negishi K. , Teranishi T. , Hidaka S. , Hida S. , Naka K.‐I 
Published: January 2005

AbstractBy means of a histofluorescence technique, a comparative study was conducted on the regional density of dopaminergic (DA) and indoleamine‐accumulating (IA) cells in carp (Cyprinus carpio) and catfish (Ictaluruspunctatus) retinas. In order to enhance detection of fluorescent cells, noradrenaline (NA; 5.0 μg) or a mixture of NA (2.5 μg) and 5,6‐dihydroxytryptamine (5,6‐DHT; 2.5 μg) was intravitreally injected into the eyes 2–3 hr before enucleation. DA and IA cells were counted systematically in space on flat‐mounted preparations. Both classes of cells were found to be distributed similarly in the two species of fish; the cell density is highest in the circumferential margin of the retina, and is slightly higher in a region dorsal to the optic disc than in the surrounding area. Differences in the distribution pattern of the cells between carp and catfish retinas were as follows: (a) the DA cell density is higher over the whole retinal field in carp (the mean density ± SD = 34 ± 16 cells/mm2) than in catfish (13 ± 7 cells/mm2); (b) the region where the density is slightly higher than in the surrounding area is restricted to a small area immediately dorsolateral to the optic disc in carp, while it is relatively broadly placed dorsal to the optic discs, forming a horizontal band in catfish; (c) the density ratio of DA cells to IA cells is 1:l in carp but 1:2 in catfish; and (d) catfish DA cells seem to be more irregular than carp DA cells in shape, size, dendritic arborization, uptake preference for monoamines intravitreally injected, and also in depth location seen in radial cryosections.
Metabolism of cadaverine and pipecolic acid in brain and other organs of the mouse
Authors: Nomura Y. , Schmidt‐Glenewinkel T. , Giacobini E. , Ortiz J. 
Published: January 2005

AbstractCadaverine and pipecolic acid metabolism was investigated in vitro in several organs of the mouse by measuring14CO2formation from labeled precursors. The liver showed the highest formation of14C02from [ 1,5‐14C]‐cadaverine, whereas brain demonstrated a much lower formation. Anaerobiosis or inhibition of monoamineoxidase (MAO) activity significantly reduced14C02formation in every organ, but inhibition of diamine oxidase (DAO) activity had no effect in brain and kidney. Piperidine was formed from cadaverine in vitro only in the large intestine and its content. This formation is probably of bacterial origin. Under a variety of experimental conditions we were unable to demonstrate any formation of piperidine in brain from cadaverine. Biosynthesis in vitro of [3H]‐piperidine from D, L‐ [3H]‐pipecolic acid was very low in brain and kidney. With the exception of brain and kidney, no other organs showed any formation of [3H]‐piperidine. Neither MAO nor DAO inhibition influenced [3H]‐piperidine formation in the large intestine with its content. Following 1 hr incubation at 37°C under aerobic conditions, the levels of [14C]‐pipecolic acid and [3H]‐piperidine recovered from mouse brain homogenate did not indicate any significant degradation of these two substances. Our results suggest that under in vitro conditions, cadaverine is not a precursor of piperidine in brain, liver, heart, and kidney and that only very low levels of piperidine can be formed from pipecolic acid in brain. Out side the brain, formation of piperidine from pipecolic acid is detectable only in kidney and in the content of the large intestine. The latter is probably of bacterial origin. Our results do not support previous findings from other authors on an endogenous origin of piperidine in brain from cadaverine and pipecolic acid, and they suggest that (a) cadaverine is not a precursor of piperidine in brain, (b) the conversion of pipecolic acid into piperidine in the brain does not constitute a major metabolic pathway, and (c) the main source of piperidine in the CNS may be of nonneural origin.
Axonal transport of glycerophospholipids in regenerating sciatic nerve of the rat during aging
Authors: Alberghina Mario , Viola M. , Moschella F. , Giuffrida A. M. 
Published: January 2005

AbstractThe effect of age upon the axoplasmic transport of glycerophospholipids has been studied using as a model the regenerating sciatic nerve of young (2‐month‐old), young adult (6‐month‐old), middle‐aged (16‐month‐old), and aged (20‐month‐old) male rats. The right sciatic nerve was crushed 0.5 mm down the incisura ischiadica. Four and nine days after the lesion, a mixture of [2‐3H] glycerol and [methyl‐14C] choline was bilaterally injected into the spinal cord, at a level of the L4‐L5 vertebrae. The animals were killed 18 hr after the isotope injection. Proximal and distal portions of crushed nerve and of contralateral sham‐operated ones were dissected and consecutive 5‐mm segments were subjected to lipid extraction and analysis.The findings of the present study are summarized as follows: (1) The accumulation of labeled lipid material axonally transported four days after nerve injury was mainly located at the crush site in young, young adult, middle‐aged, and aged rats. The accumulation of both 3H‐glycerolipids and 14C‐choline phospholipids in postcrush segments was markedly higher for young and young adult than for aged rats, four and nine days after crush; (2) the average rate of axonal regeneration, determined between days 4 and 9 following crush injury was 3.6 and 4.2 mm/day for 2‐month‐old and 6‐month‐old rats, respectively; it decreased to the value of 2.5 mm/day for 16–20‐month‐old rats.
Glial endocytosis of protein in the traumatized brain
Authors: Trachtenberg Michael C. 
Published: January 2005

AbstractThe effect of trauma on the clearance of exogenous protein from the extracellular space of the brain was examined in monkeys and rats. Manual contusion of the monkey temporal lobe or air puff contusion of the rat parietal cortex resulted in intense glial uptake of the protein marker, horseradish peroxidase (HRP). There was no evidence of punctate or diffuse material in neurons at or distant from the trauma site. Cellular uptake was evident as early as 4 hr post trauma and reached maximal expression 24 hr post injury. By 72 hr post trauma few labeled cells could be seen. The extent of the glial uptake of protein was suggested by the decrease in extracellular marker in the vicinity of the labeled cells and by calculation of the fraction of glia so labeled. Sites of labeled glia were highly localized, corresponding to regions of stress. The corpus callosum was most clearly labeled in the rat experiments. The data suggest that in cases of traumatic injury to the brain, glia may be selectively stimulated to pronounced uptake of protein marker and thus may represent a potential means of clearing the extracellular space of extravasated serum protein.
The site of the integration of muscular activity and respiration
Authors: Hoff H. E. , Schuhmann R. E. , Coles S. K. 
Published: January 2005

AbstractAcutely decerebrate (midcollicular) cats do not, or rarely if ever, walk spontaneously; nor do they show phasic movements of progression. After low thoracic cordotomy in a Schiff‐Sherrington preparation with enhanced forelimb rigidity, appproximately 50% of the preparations begin to show spontaneous locomotory movements in the forelimbs. In some cases these movements are in periodic bursts, and at these times are associated with waxing hyperpnea beginning before the onset of the forelimb movements. This indicates the presence of an intrinsic exercise hyperpnea mechanism mediated within the central nervous system in centers caudal to the hypothalamus.