bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural changes in astrocytes induced by seizures in a model of temporal lobe epilepsy
Authors: Castiglioni A. J. , Peterson S. L. , Sanabria E. L. , Tiffany‐Castiglioni E.
Published: January 2005

Injection of iron‐chloride solution unilaterally into the hippocampus of albino rats induced transient seizure activity which lasted approximately 2 weeks. Frontal and parietal cortices of experimental rats, control rats which received NaCl injections, and unoperated normal rats were compared by means of a Golgi stain which demonstrated astrocytes and their processes in their entirety. Morphometric analysis showed that cortical astrocytes of rats having intermittent seizure activity over a prolonged period were significantly larger than cortical astrocytes of control rats. These findings indicate that seizure activity causes structural brain changes at anatomical sites distant from the hippocampal seizure focus. Similar phenomena may contribute to the development of psychiatric and neurological changes in the epileptic patient.
In vivo labeling of phencyclidine (PCP) receptors with 3H‐TCP in the mouse brain
Authors: Maurice T. , Vignon J.
Published: January 2005

The phencyclidine (PCP) derivative N‐[1‐(2‐thienyl) cyclohexyl]‐piperidine (3H‐TCP) was used to label in vivo the N‐methyl‐D‐aspartate (NMDA) receptor‐associated ionic channel in the mouse brain. After the injection of a tracer dose of 3H‐TCP, a spread labeling throughout the brain was observed, but was the highest in the cerebellum. Preadministration of unlabeled TCP (30 mg/kg) resulted in a 90% reduction of 3H‐TCP binding. PCP, TCP, MK‐801, dexoxadrol, ketamine, and SKF 10,047 isomers dose‐dependently prevented the in vivo 3H‐TCP binding. ID50 determined in the cerebrum and the cerebellum were respectively correlated with K0.5 for 3H‐TCP high (rat cortex) and low affinity (rat cerebellum) sites in vitro. The pharmacological specificity of the 3H‐TCP binding site in the cerebellum was significantly different from that in the cerebrum. ID50 values were generally higher than in the cerebrum and, particularly, MK‐801, the most potent drug in the cerebrum, was without significant effect in the cerebellum, at any time and at doses as high as 30 mg/kg. N‐[1‐(2‐benzo(b) thiophenyl) cyclohexyl]piperidine (BTCP), desipramine, and atropine showed a more efficient prevention of 3H‐TCP binding in the cerebellum than in the cerebrum. The prevention of the binding by TCP or PCP, at doses close to their ID50 values, was rapid and then decreased slowly. The effect of MK‐801 was long‐lasting. This study confirm previous in vitro studies: 3H‐TCP is an efficient tool for the labeling of the NMDA receptor‐associated ionic channel. particularly, low affinity sites were identified in the cerebellum with the same pharmacological properties as in vitro in the same region.
Establishment of a permanent rat brain‐derived glial cell line as a source of purified oligodendrocyte‐type 2 astrocyte lineage cell populations
Authors: Aloisi Francesca , Sun D. , Levi G. , Wekerle H.
Published: January 2005

A permanent glial cell line (L3) has been established from mixed glial cultures obtained from neonatal rat forebrain by repetitive passaging and selection of the process‐bearing cells growing on top of a flat cell monolayer. Continuous propagation of the process‐bearing cells was supported by the flat cells, of presumed astroglial origin, which were present in negligible amounts following each passage but then grew and formed a basal, feeder layer. Throughout a culture period of over 2 years, the L3 cells have maintained a stable morphological and antigenic phenotype. In serum‐containing culture medium, most of the process‐bearing cells expressed at the same time features of immature oligodendrocytes (O4 positivity) and of astrocytes [glial fibrillary acidic protein (GFAP) positivity]. A smaller proportion of them was labeled by the monoclonal antibody LB1. LB1 + or O4+ cells were rarely GFAP−, and GFAP+ cells were rarely LB1− or O4−. GalC+ oligodendrocytes were seen only occasionally, but the proportion of these cells increased up to 30% upon culturing in chemically defined medium containing 0.5% fetal calf serum. The L3 process‐bearing cells accumulated the neurotransmitter γ‐aminobutyric acid (GABA), expressed the proteoglycan chondroitin sulfate, and responded to the mitogenic action of platelet‐derived growth factor (PDGF) and fibroblast growth factor (FGF). All these properties are characteristic of cells belonging to the 0‐2A (oligodendrocyte‐type 2 astrocyte) cell lineage. The L3 flat cells were largely negative for the glial markers tested, but resembled type 1 astrocytes in their ability to support the growth of 0‐2A lineage cells. The L3 cell line represents a unique source of large numbers of purified 0‐2A‐like lineage cells and may therefore represent a useful experimental system to analyze the functional and developmental properties of this glial population.
Chemotaxis by a CNS macrophage, the microglia
Authors: Yao J. , Harvath L. , Gilbert D. L. , Colton C. A.
Published: January 2005

Microglia demonstrate many characteristics similar to those seen in monocytes and tissue‐specific macrophages, including phagocytosis, production of oxygen radicals, and growth factors and expression of MHC antigens. We have examined the ability of microglia, cultured from the cerebral cortices of neonatal rats, to demonstrate another important functional characteristic of monocytic‐derived cells, that is, chemotaxis. Our results show that cultured rat microglia demonstrate chemotaxis to complement dependent chemoattractants such as recombinant C5a, zymosan activated serum, and to rat serum as well as to transforming growth factor‐beta, a chemoattractant produced by platelets, Microglia fail to migrate to bacterial dependent chemoattractants such as the N‐formyl peptides. The failure to respond is not dependenton maturational state of the microglia. Treatment with DMSO or casein, agents known to induce morphological and functional changes in cultured microglia reminescent of a “resting” and an “activated” macrophage, respectively, do not alter the response to fMet‐Leu‐Phe. In addition, the chemotactic response to serum in DMSO or casein‐treated cells is the same as the response seen in untreated day 10 cultured microglia or untreated age‐matched controls. The ability of microglia to migrate in response to inflammatory mediators suggests that these cells can move to sites of injury, thereby enabling them to participate in an inflammatory response.
Differentiation of rat hippocampal neurons induced by estrogen in vitro: Effects on neuritogenesis and Na,K‐ATPase activity
Authors: Blanco G. , Diaz H. , Carrer H. F. , Beaugé L.
Published: January 2005

To gain insight into the mechanisms responsible for differentiation of hippocampal neurons growing in vitro, the effects of estrogen on neuritic development and on activity and distribution of isoforms of the Na,K‐ATPase, were evaluated. Dissociated cells from hippocampi of 19‐day‐old rat fetuses were raised for 5 days in the presence or absence of 100 nM estradiol‐17β (E2) in minimum essential medium supplemented either with 10% untreated fetal calf serum (MEM‐10) or with 10% fetal calf serum previously adsorbed with dextran‐activated charcoal (MEM‐10‐Cha). Cultures in MEM‐10 showed larger neuritic length and increased levels of Na,K‐ATPase activity than cultures in MEM‐10‐Cha. In cells cultured in MEM‐10 medium, the addition of E2 resulted in selective enhancement of axonal length with a concomitant increase in the alpha‐2 isoform of the Na,K‐ATPase, whereas a decrease was found in the form most sensitive to ouabain; the total enzymatic activity remained unchanged. Conversely, in cultures raised in MEM‐10‐Cha, E2 did not affect Na,K‐ATPase activity or neuritogenesis. These results show presumably independent probes of cellular differentiation of hippocampal neurons (i.e., neuritogenesis and patterns of Na,K‐ATPase activity) were concurrently regulated by E2 and that such regulation depended on interaction with factor(s) present in calf serum. The well‐known neuritogenic effect of E2 is hereby extended to hippocampal neurons. although for these cells it seems to be restricted to axons.
Development of cholinergic markers in the neuroblastoma, N1E‐115
Authors: Kumar U. , Sellström Å.
Published: January 2005

The neuroblastoma, N1E‐115, was grown for 9 days after subcultivation. The development of acetylcholinestrase (AChE), choline acetyltransferase (CAT), QNB‐binding, choline uptake, and acetylcholine release was measured on days 1, 3, 6, and 9. In paralell experiments the irreversible AChE inhibitor soman was added to neuroblastoma on day 1 and the development of the above parameters except for release, was followed.

AChE activity in the normal cells was found to develop also after confluency, whereas CAT activity and QNB‐binding followed the development of most of the cellular proteins, i.e., ceased to develop at confluency. Both choline uptake and acetylcholine release appeared independent of cellular development.

In the soman‐treated cells the development of AChE was inhibited for up to 6 days and thereafter developed with the sama rate as in the normal cells. CAT and QNB‐binding developed as in the normal cells, but at a significantly reduced level. The development of choline uptake was not significantly different in soman‐treated and normal neuroblastoma.

It is concluded that the development of the cholinergic marker QNB‐binding is intimately associated with that of the “presynaptic” marker CAT, whereas the development of AChE seems to be unrelated to these cholinergic parameters. The choline transport and the acetylcholine release seem to be equally well expressed on all the days studied.
Expression of myelin protein gene transcripts by schwann cells of regenerating nerve
Authors: Mitchell L. S. , Griffiths I. R. , Morrison S. , Barrie J. A. , Kirkham D. , McPhilemy K.
Published: January 2005

The expression of many myelin‐specific molecules in Schwann cells is profoundly decreased following denervation. This study examines the early reexpression of myelin protein genes associated with reinnervation. Following sciatic nerve crush, the distal, regenerated nerve was divided into appropriate (2.5 or 5 mm) consecutive lengths in which gene expression was monitored using Northern blotting, in situ hybridization, and immunostaining. The spatial separation of the distal axon tip and the more proximally located Schwann cells showing initial upregulation of Po mRNA was constant over the period of 5–13 days after crush at approximately 3–4 mm in fixed, processed material. Axons associated with Schwann cells showing the initial upregulation were completely or partially enveloped in Schwann cell cytoplasm, with very few having any degree of ensheathment. It is probable that only a limited axon‐Schwann cell contact is required for induction of the myelin protein genes. Myelin‐associated glycoprotein mRNA was upregulated prior to those for Po and myelin basic protein which had similar time courses. Reexpression of galactocerebroside also preceded that for Po mRNA. Signal abundance for all myelin proteins decreased in a proximal to distal direction from the crush site, and with time the “wave” of upregulation moved distally down the nerve. In the more proximal, remyelinating zones, the signal intensity exceeded that of the contralateral normal nerve. Signal intensity also varied considerably between adjacent, expressing Schwann cells. The data provide further evidence of the strong temporospatial relationship between axons and the regulation of myelin protein genes in Schwann cells.
Isolation of cDNAs from a mouse astroglial cell line by a subtracted cDNA library
Authors: Rhyner T. A. , Lecain E. , Mallet J. , Pessac B.
Published: January 2005

Astrocytes belong to the glial cell population and represent a major subclass of the CNS. Although different subtypes of astrocytes have been described according to their morphological characteristics, biochemical markers of each subtype of astrocytes are not yet available. We have thus undertaken to compare gene expression pattern of different astroglial subtypes. In this study we have taken advantage of two astroglial cell clones derived from 8 day postnatal mouse cerebellar explants and which might be the in vitro equivalents of the velate protoplasmic (D19) and of the Golgi‐Bergmann (C8S) astrocytes (Alliot and Pessac, Brain Res, 306: 283–291, 1984). We have constructed a subtracted cDNA library derived from cytoplasmic poly(A)+ RNAs of the D19 cell line. This library was enriched 12‐fold for D19 specific sequences by subtractive hybridization with an excess of cytoplasmic poly(A)+ RNAs purified from the C8S astroglial clone. This subtracted library was differentially screened with cDNA probes derived from D19 and C8S cell lines; both probes were subtracted with C8S poly(A)+ RNAs. Eight cDNA clones corresponding to transcripts overexpressed in D19 were selected. Three cDNAs encode for smooth muscle actin, one for fibronectin and one for polyadenylate binding protein. The three other gene products have not been previously reported. The in vivo distribution pattern of these sequences in various mouse adult tissues shows that all these transcripts are expressed in the cerebellum and/or in the brain.
Characterization of nerve growth factor binding to embryonic rat spinal cord neurons
Authors: Marchetti D. , McManaman J. L.
Published: January 2005

The binding of iodinated β‐nerve growth factor, [125I]‐NGF, to embryonic (E16) rat spinal cord cells, was investigated to characterize the binding properties and cellular distribution of nerve growth factor receptors. Spinal cord cells prepared without trypsin yielded two classes of NGF binding sites with Kd's of 3 × 10−11 M and 4 × 10−9 M. Fractionation of the cells by discontinuous gradients composed of 8%, 12%, and 17% metrizamide was used to separate motoneurons from other cell types. The motoneuron enriched fraction (8% metrizamide) contained approximately 10% of the cells and 64% of the choline acetyltransferase (ChAT) activity. In contrast, the 12% metrizamide fraction contained most (51%) of the cells and 36% of the ChAT activity, while the 17% metrizamide fraction contained the remainder of the cells and negligible amounts of ChAT activity. Characterization of [125I]‐NGF binding to each metrizamide fraction showed that the motoneuron‐en‐riched fraction exhibited both high and low affinity binding sites, while the other metrizamide fractions exhibited only the low affinity binding sites. These findings indicate that although low affinity NGF receptors appear to be relatively evenly distributed amongst embryonic rat spinal cord cells, high affinity NGF receptors are found primarily on motoneurons.
Effects of in utero ethanol exposure on the developing dopaminergic system in rats
Authors: Druse M. J. , Tajuddin N. , Kuo A. , Connerty M.
Published: January 2005

Previous studies from this and other laboratories suggest that dopamine is decreased in selected brain regions of postnatal rats exposed to ethanol in utero. The present study expands previous work by examining the effects of in utero ethanol exposure on dopamine D1 and D2 binding sites and dopamine uptake in postnatal rats. In addition, dopamine content in the brain stem and frontal cortex of fetal and neonatal rats was examined.

The experimental results indicate that in utero ethanol exposure markedly affects the postnatal development of the dopaminergic system in the striatum and frontal cortex. We observed a marked, transient deficiency of striatal dopamine (>40% decrease at 19 days) and dopamine uptake sites (∼ 25% decrease in V max at 35 days). The Bmax for striatal dopamine D1 binding sites was decreased by > 20% at both 19 and 35 days. Cortical D1 sites were markedly decreased at 19 days (> 40%). In contrast, the number of striatal D2 receptors was unaffected by in utero ethanol exposure at both ages.

Analysis of tissue from neonatal rats demonstrated a marked dopamine deficiency in ethanol‐exposed rats on postnatal day 5. In light of the proposed morphogenic actions of dopamine early in development, it is possible that the early dopamine deficiency contributes to the abnormal postnatal development of the dopaminergic system.
Cholesterol esterification and Niemann–Pick disease: An approach to identifying the defect in fibroblasts
Authors: Bowler L. M. , Shankaran R. , Das I. , Callahan J. W.
Published: January 2005

Fibroblasts from 13 patients with the clinical phenotype of type IIS, Niemann–Pick disease were evaluated for their ability to incorporate oleic acid into cholesterol esters via an LDL responsive mechanism. Eight patients displayed a severe deficiency (< 8% of normal) of cholesterol ester (CE) synthesis while a clinically less affected group displayed intermediate levels (36% of normal) of synthetic capacity with no detectable overlap between these groups and the control range. There was no deficiency in cholesterol ester production in fibroblasts from a patient with Zellweger's disease, a disorder characterized by altered peroxisomes and abnormal peroxisomal cholesterol metabolism, while in I‐cell disease, characterized by a primary deficiency of a phosphotransferase which results in altered targeting of lysosomal hydrolases, it was reduced to 25% of the control level. To further implicate lysosomal proteins in the etiology of type IIS, Niemann–Pick disease we measured the effect of correction (conditioned) medium, and the lysosomotropic agent, NH4Cl on cholesterol ester synthesis in fibroblasts. NH4Cl completely inhibited incorporation into CE by normal cells, thus mimicking the CE defect in type IIS, Niemann–Pick cells. Conditioned medium had no effect on incorporation into CE synthesis but medium conditioned in the presence of 10 mM NH4Cl stimulated incorporation into CE in the control but not in Niemann–Pick cells. When Niemann–Pick cells cultured in the presence of NH4Cl were challenged to synthesize CE in the absence of NH4Cl, a significant enhancement of CE synthesis was noted in representative cell lines from both groups of patients. These results indicate that two levels of deficiency can be clearly identified and that this biochemical phenotype appears to correlate with the severity of clinical disease. We suggest that the defect in patients with intermediate levels of CE synthesis may reside in a phosphomannosyl‐directed glycoprotein that is targeted to the lysosome via the phosphomannosyl receptor, while the most severely affected patients may be defective in another type of protein.
Cortical glucose metabolism in parkinson's and alzheimer's disease
Authors: Peppard R. F. , Martin W. R. W. , Clark C. M. , Carr G. D. , McGeer P. L. , Calne D. B.
Published: January 2005

Characteristic regional patterns of decreased cerebral glucose metabolism (rCMRG) have been described in a variety of neurodegenerative conditions associated with dementia. The present study was undertaken to determine whether the metabolic pattern in Parkinson's disease is altered by the presence of impaired cognitive function. Glucose metabolism was measured with positron emission tomography in 6 patients with Parkinson's disease and dementia (PDD), 8 patients with Parkinson's disease and normal cognition (PD), and 6 patients with Alzheimer's disease (AD). All AD patients subsequently had the diagnosis proven neuropathologically at autopsy. Correlation coefficients of the metabolic rates across 32 regions of interest were calculated between each pair of patients. Q‐component analysis of the correlation matrix showed that the AD and PD groups formed two distinct clusters and that the PDD group had a metabolic pattern which was similar to that of the AD group. Comparison of standardized rCMRG values showed that the PDD group differed from the PD group in having significantly lower relative rCMRG in the left perirolandic and bilateral angular gyrus regions. There were no significant differences between the PDD and AD groups. These results suggest a similar pattern of cortical dysfunction in both Alzheimer's disease and in Parkinson's disease/dementia.
Recombinant human β‐nerve growth factor (NGF): Biological activity and properties in an enzyme immunoassay
Authors: Söderström S. , Hallböök F. , Ibáñez C. F. , Persson H. , Ebendal T.
Published: January 2005

Nerve growth factor (NGF) supports sympathetic and sensory neurons in the peripheral nervous system and also functions in the development and maintenance of cholinergic neurons in the basal forebrain. NGF distribution can be studied in the brain of the rat and mouse with the use of a sensitive two‐site enzyme immunoassay (EIA) for mouse NGF. It would be of interest to measure the NGF protein also in the human brain, especially against the background that the cholinergic neurons are severely deteriorated in senile dementia of the Alzheimer type. The limited immunological cross‐reactivity between NGFS from different species has previously hampered attempts to determine levels of the human NGF. We have now examined the biological activity and immunological properties of human recombinant NGF protein in medium conditioned by COS cells transfected with the human NGF gene. The human NGF behaved similar to mouse NGF in a sympathetic ganglion bioassay. The monoclonal antibody 27/21 to mouse NGF was shown to effectively block the activity of both the human recombinant NGF and mouse native NGF. A two‐site EIA using monoclonal antibody 27/21 was optimized. Under the conditions used, the EIA detected the human recombinant NGF with the same sensitivity (1 pg/ml) as shown for the mouse NGF. It should now be possible to test this EIA also on homogenized tissue to examine human NGF in brain samples from Alzheimer patients and age‐matched controls.
Basic fibroblast growth factor: A potential autocrine regulator of human glioma cell growth
Authors: Gross J. L. , Morrison R. S. , Eidsvoog K. , Herblin W. F. , Kornblith P. L. , Dexter D. L.
Published: January 2005

Basic fibroblast growth factor (bFGF) is a potent mitogen and angiogenic factor. bFGF is expressed by a variety of solid human tumors and has been implicated as an autocrine regulator of tumor growth. Different solid tumor lines including glioma, colon carcinoma and melanoma were examined for intracellular immunoreactive bFGF, high‐ and low‐affinity bFGF receptors and mitogenic response to bFGF when grown in chemically defined medium. All tumor lines contained significant levels of bFGF. In addition, all tumor lines contained subsets of five forms of inmiunoreactive bFGF, as well as 0.68–20 × 106 low affinity bFGF binding sites (Kd = 15–300 nM). Most, but not all lines exhibited high affinity bFGF receptors (Kd = 25–40 pM). Glioma cell lines were distinguished by expressing the highest levels of bFGF protein as well as the most high‐affinity receptors for bFGF. Furthermore, glioma cell lines were the only tumor type mitogenically responsive to bFGF. These results indicate that glioma cells express high levels of this potent mitogen and angiogenic factor relative to human colon carcinoma and melanoma cells. The expression of bFGF and bFGF receptors by glioma cells may be related to abnormal growth and neoplastic progression in these tumors.
Single K+ channel properties in cultured mouse Schwann cells: Conductance and kinetics
Authors: Verkhratsky A. , Hoppe D. , Kettenmann H.
Published: January 2005

Cultured Schwann cells are characterized by a strong outward rectification of the membrane; the threshold of the outward currents is close to the resting membrane potential of about ‐50 mV (Gray et al.: In Ritchie, Keynes (eds): Ion Channels in Neural Membranes. New York: Alan R. Liss, Inc., pp 145–157, 1986). These outward currents show up a heterogeneity among the cultured Schwann cells: some cells displayed inactivating, others non‐inactivating outward currents (Hoppe et al.: Pflügers Arch 415:22–28, 1989). In this study we characterized the single channel currents using the patch‐clamp technique in the intact patch recording configuration. The conductance of all recorded channels was 10‐12 pS. (5.6 mM [K+]o) These channels were K+ selective since changes in extracellular [K+] resulted in changes of the reversal potentiaJLas predicted for an exclusively K+ selective pore. The reversal potentials also predicted an intracellular [K+] of 60 mM indicating that the K+ equilibrium potential is slightly negative to the membrane potential. Analysis of the kinetic behavior of the channels resolved two different types of behaviour:40% inactivated during a depolarizing voltage step, the others showing no sign of inactivation. The analysis of open probability and gating properties in the steady state showed up more differences between these two channel types: mean open probability peaked at about 10 mV for inactivating channels, while it continuously increased for non‐inaclivating channels. The inactivation time constants of averaged single channel and whole cell currents were similar and showed both a similar voltage dependency. We conclude that cultured. Schwann cells express either two types of K+ channels with Slimlar conductance or a channel which can acquire two functional states and that these channels can account for the different types of K+ currents observed in these cells.
Lithium chloride alters cytoskeletal organization in growing, but not mature, cultured chick sensory neurons
Authors: Hollander B. A. , Bennett G. S.
Published: January 2005

Biochemical analysis indicates that lithium ion (Li+) has deleterious effects on the metabolism of at least two elements of the cytoskeleton in cultured chick dorsal root ganglia (DRG) neurons. Phosphorylation ofnewly synthesized middle molecular mass neurofilament polypeptide (NF‐M) is inhibited by 10‐25 mM LiCl, and tubulin (Tb) synthesized in the presence of Li+ is subject to rapid degradation. These Li+‐in duced metabolic abnormalities are accompanied by alterations in cellular and cytoskeletal morphology. Treatment of cultures having vigorously growing neurites with 25 mM LiCl results in the cessation of net neurite growth, without causing neurite retrac tion. Indirect immunofluorescence reveals that in these cultures Li+ provokes an aggregation of NF protein into a dense knot in the cell body/proximal neurite region. The knots contain accumulations of all three NF polypeptides and electron microscopic observation demonstrates that the knots contain in tact, but disorganized, filaments. Both the inhibition of neurite outgrowth and NF collapse are reversible. Tubulin and intact microtubules are redistributed in immature cultures treated with Li+ insofar as they are excluded from the NF knots. Neurons in estab lished cultures (e.g., 7 days and beyond) fail to show any difference between Li+ treatment and control conditions in the morphology of the cytoskeletal ele ments examined.
α2‐Adrenoceptors are not involved in the regulation of striatal glutamate release: Comparison to dopaminergic inhibition
Authors: Harsing L. G. , Vizi E. S.
Published: January 2005

Striatal slices from the rat were loaded with [3H]glutamate ([3H]Glu) superfused measure release of radioactivity at rest and during potassium‐evoked depolarization. Addition of KC1 (22‐40 mmol/liter) to the perfusion fluid enhanced the release of tritium in a concentration‐dependent manner, and this release was abolished by omission of CaCl2. High‐performance liquid chromatography (HPLC) separation coupled with radiochemical delection revealed that 23% and 41% of the tritium efflux detected in the perfusion fluid under resting conditions and during potassium stimulation, respec‐lively, was due to [3H]Glu. At the end of the super‐fusion about 63% of residual tritium content in the tissue was [3H]Glu. Tritium efflux in response to KCI excess was significantly higher from striatum dissected from 6‐hydroxydopamine‐pretreated rats. Apomorphine decreased, the KCl‐evoked release of [3H]Glu haloperidol exerted the opposite effect, Yohimbine, which antagonized the decrease of dopa accumulation elicited by apomorphine in NSD‐1015 and γ‐butyrolactone‐pretreated rat caudate nucleus, also reversed the appmprphine inhibition of the, re‐lease of [3H]Glu evoked by depolarization. The selective α2‐adrenoceptor antagonist CH‐38083, however, did not modify the apomorphine inhibition of [3H]GIu release or dopa accumulation, andthe α2‐adrenoceptor agonist xylazine did not alter tritium efflux from striatum preloaded with [3H]Glu. These findings suggest that release of glutamate (Glu) from the corticostriatal pathway is under tonic control of dopamine released from nigrostriatal neurons, and α2‐adrenoceptors are not involved in the regulation of glutamatergic transmission in the rat striatum. The effect of yohimbine on Glu release is attributed to its antidopaminergic rather than α2 adrenoceptor blocking effect.
Role of nucleus basalis in cholinergic control of cortical blood flow
Authors: Scremin O. U. , Torres C. , Scremin A. M. E. , O'Neal M. , Heuser D. , Blisard's K. S.
Published: January 2005

The present investigation was designed to determine the effect of lesions localized to the nucleus basalis/ substantia innominata (NB) on resting and cholin‐ergically activated regional cerebral cortical blood flow (rCBF). Ibotenic acid (l0μg) was infused locally at 1 mm caudal to bregma, 3 mm lateral to the midline, and 8 mm below the cortical surface. Effectiveness of lesions was demonstrated by histological verification of lesion sitesand determination of choline acetyltransferase activity in cerebral cortex homogenates. rCBF was measured with the autoradiographic iodo‐14C‐antipyrine technique. Resting rCBF was similar in the hemisphere that received the NB lesion and in the contralateral (intact) side in all regions examined. Physostigmine intravenous infusion (33 μg kg −1 min −1) enhanced rCBF in frontal, parietal, occipital, and temporal cortex. The increase was symmetrical, however, indicating inability of NB lesion to affect this phenomenon. It is concluded that the cortical cholinergic afferents originating in the NB are not involved in the control of rCBF.
Cerebrospinal fluid catecholamine metabolites in HIV‐infected patients
Authors: Larsson M. , Hagberg L. , Forsman A. , Norkrans G.
Published: January 2005

Twenty‐eight HIV‐seropositive individuals—11 asymptomatic cases, 8 with lymphadenopathy syndrome (LAS), and 9 with AIDs—were investigated. Clinical staging of the AIDS dementia complex was done in the 9 AIDS patients. The catecholamine metabolites 3‐methoxy‐4‐hydroxyphenylglycol (MHPG) and homovanillic acid (HVA) in CSF were determined in all the HIV patients and in 20 healthy volunteers. The CSF MHPG levels did not differ significantly between healthy subjects and HIV‐infected patients at any stage of the infection. The CSF concentrations of HVA differed between the groups only during the AIDS stage. The mean CSF HVA value in the AIDS patients was 42% lower than in the healthy subjects and significantly lower than in any other stage of HIV infection (P > .01). Patients with signs cf the AIDS dementia complex had reduced CSF HVA levels, but there was no clear relationship between HVA concentration and stage of the AIDS dementia complex.
Differential taurine uptake in central and peripheral regions of goldfish retina
Authors: Lima L , Matus P. , Drujan B.
Published: January 2005

The transport system of taurine was investigated in fragments of goldfish retina prepared from the total tissue and from concentric regions: center and periphery. A high‐affinity, saturabie, sodium‐dependent system was demonstrated in the three types of fragments. The Kmfor one‐site analysis was similar in the two regions and the total retina. The analysis for two sites revealed a significant higher Km, for the high‐affinity site in fragments from the central region. The maximal uptake rate was higher in the central zone than in the total retina or the periphery. The Hill slopes obtained from saturation experiments of fragments of total retina, center, and periphery were similar to one other and near to 1. The slope of the time course uptake was intermediate for total retina and higher in the center than in the periphery. Hy‐potaurine and beta‐alanine were found to inhibit taurine uptake, but GABA was a weak inhibitor. The values of Kifor hypotaurine by one‐ and two‐site analysis were lower in the central region. The disruption of photoreceptors by shaking did not modify significantly the uptake of the amino acid. Remotion of endogenous taurine by dialysis of central and peripheral fragments increased the uptake in the periphery, but not in the center. The differences observed among the three samples revealed less affinity and high capacity for taurine uptake in the center, plus a higher sensitivity of inhibition. In addition, the peripheral zone had a greater affinity for taurine, and the maximal velocity of the entrance seems to bg inhibited by the higher concentration of the amino acid in this zone. These observations may reflect differences between proliferating and non‐proliferating regions of : The retina (i.e., periphery and center).
Purinergic stimulation of astroblast proliferation: Guanosine and its nucleotides stimulate cell division in chick astroblasts
Authors: Kim J.‐K. , Rathbone M. P. , Middlemiss P. J. , Smith R. W. , Hughes D. W.
Published: January 2005

A highly active fraction that was mitogenic for astroblasts but which contained no amino acids was identified during the purification of peptides from chick embryo brains. This material was purified by ultracentrifugation, ultrafiltration through Diaflo PM‐30 and YM‐2 membranes and retention on Diaflo YC‐05, followed by ion exchange chroniatography and reversed phasehigh performance liquid chromatography (HPLC) on a C18 Deltapak column. On thin layer chromatography and HPLC the material co‐chromatographed with authentic commerciallyobtained GMP. Its ultraviolet absorption spectrum was also identical with that of GMP. 1H and 31P nuclear magnetic resonance spectra of the isolated material were identical with those of GMP. The close match between the fast atom bombardment (FAB) mass spectra of the unknown material and authentic GMP indicated that the unknown material was GMP of molecular weight 363 Da. Authentic, commercial GMP stimulated the growth of cultured chick astroblasts in the same dose‐dependent manner as the material from chick embryo brains; maximal stimulation was at 50 μM. Guanosine, GDP, and GTP also stimulated cell proliferation. The nucleotides were equally as effective as guanosine. 5′‐Guanylyl imido‐diphosphate, guanosine 5′‐O‐(2‐thiodiphosphate), and guanosine 5′‐N‐(3‐thiotriphosphate), guanine nucleotides which are relatively resistant to enzymatic hydrolysis, were also mitogenic, indicating that the nucleotides do not need to be degraded to nucleosides to be active and that they probably act extracellularly. Guanine nucleosides and nucleotides prompted astroblast growth when other growth factors were removed from the culture medium. The mitogenic effects of guanosine and its nucleotides were inhibited in a dose‐dependent fashion by micromolar concentrations of theophylline, a characteristic of phenomena mediated by purinergic receptors. Guanosineand its nucleotides are released in micromolar concentrations by hypoxic ordying cells. Under these circumstances these compounds may stimulate division of adjacent cells in vivo.
Differentiation of PC12 cells with K‐ras: Comparison with nerve growth factor
Authors: Simpson D. L. , Dickens G. , Doll S. , Koizumi S. , Tocco M. , Okuda O. , Oshima M. , Rudkin B. B. , Brightman M. , Guroff G.
Published: January 2005

The cell line PC12, derived from a rat pheochromocytoma, has served as a model for studies on the mechanism of action of nerve growth factor, as well as for the exploration of neuronal differentiation in general. When treated with nanomolar concentrations of nerve growth factor, these neoplasticchromaffin‐like cells stop dividing and acquire, for all intents and purposes, the phenotype of mature sympathetic neurons. This phenotype is characterized by the extensive outgrowtb of electrically excitable neurites, the ability to form functional synapses, and the acquisition of a number of biochemical markers.

Treatment of PC12 cells with retro viral vectors encoding the K‐ras, the N‐ras, or the v‐src oncogenes also produces a marked morphological differentiation very similar to that seen upon treatment with nerve growth factor. Treated cells stop dividing and develop an extensive network of neurites. It has recently been shown that PC12 cells differentiated with v‐src, while resembling, morphologically, those treated with nerve growth factor, differ substantially in the biochemical characteristics normally associated with nerve growth factor‐induced differentiation.

Cells infected with K‐ras also develop a neurite network similar to that seen after treatment with nerve growth factor. In addition, such cells develop tetanus toxin‐binding sites and saxitoxin‐binding sites, as do cells treated with nerve growth factor. Decreases in the binding of epidermal growth factor and in the activity of calpain also occur and these, as well, are characteristic of nerve growth factor‐treated cells. But the adhesive properties of cells infected with K‐ras are different than those of nerve growth factor‐treated cells, and the former do not show an increase in the NILE glycoprotein. Finally, K‐252a, an inhibitor of the actions of nerve growth factor on PC 12 cells, has no effect on the neurite outgrowth produced by infection with K‐ras. Thus, many of the key markers of nerve growth factor‐induced differentiation of PC 12 cells also appear upon differentiation with K‐ras, but there are, nevertheless, some crucial differences in the properties of these two sets of cells.
α Isoform of smooth muscle actin is expressed in astrocytes in vitro and in vivo
Authors: Lecain E. , Alliot F. , Laine M. C. , Calas B. , Pessac B.
Published: January 2005

We have previously reported that astroglial cell lines derived from spontaneously immortalized mouse cerebellar cultures as well as primary astrocyte cultures express the mRNA of the α isoform of smooth muscle actin. In this report, we have used an antiserum specific for the α smooth muscle actin protein to investigate the presence and the pattern of expression of a smooth muscle actin protein at the cellular level with immunocytochemical methods. The results show that an anti‐smooth muscle vessels α actin antiserum labels a typical actin network in the D19 astroglial cell clone and in flat astrocytes of primary cultures derived from various CNSregions of embryonic and postnatal mice. Furthermore, this antiserum labels distinct populations of astrocytes in the adult mouse brain, in particular in the corpus callosum and the fornix. However, in the corpus callosum, astrocytic processes are strongly labeled by anti‐SMV α actin antibodies only in parasagittal planes. Thus, a smooth muscle actin represents a newmarker for subsets of astrocytes.
Inhibition of mouse T‐cell proliferation by CGRP and VIP: Effects of these neuropeptides on IL‐2 production and cAMP synthesis
Authors: Boudard F. , Bastide M.
Published: January 2005

We compared the effect of two neuropeptides, calcitonin generelated peptide (CGRP) and vasoactive intestinal peptide (VIP), on mitogen‐induced murine splenocyte proliferation. Both neuropeptides exerted their maximal effect within 24 hr after activation by Con A. The combination CGRP‐VIP caused an additive inhibitory effect on T‐cell proliferation. The inhibitory effect of VIP could be correlated with a decrease in interleukin 2 (IL‐2) production, whereas CGRP did not affect this production. Since we also observed an additive inhibitory effect on T‐cell proliferation by the theophylline and CGRP or VIP combination, we measured the effect of each neuropepntide on intracellular cAMP production by enriched T‐cells: CGRP, but not VIP, strongly stimulated cAMP synthesis. Taken together, our results indicate that inhibition of murine T‐cell proliferation by CGRP and VIP is mediated by different mechanisms.
Population‐specific modulation of 5‐HT expression in cultures of embryonic rat rhombencephalon
Authors: Becquet D. , Héry F. , Héry M. , Drian M. J. , Faudon M. , König N.
Published: January 2005

This study aimed at analyzing the regulation of in vitro serotonin expression by neurons taken from different regions of the embryonic rat rhombenceph‐alon. We studied the influence of co‐culture with alar‐plate tissue using immunocytochemical and biochemical methods.

Computer‐assisted densitometry was used to estimate the co‐culture effects on the serotonin content of the cell bodies. The more dynamic aspects of serotonin expression, such as synthesis and release, were studied by measuring (3H)serotonin newly synthe‐sized from (3H) tryptophan.

The density of the immunostaining was significantly decreased in B1, B2 cells by co‐culture with both caudal and rostral alar‐plate tissue. For B4–B9 cells, only co‐culture with rostral alar‐plate tissue produced a significant decrease. The de novo synthesis of serotonin was significantly decreased in B1, B2 neurons co‐cultured with caudal alar‐plate tissue only. Once again, the B4–B9 cells proved to be less influenced by the experimental conditions, as co‐culture with both types of alar‐plate tissue produced no significant effect.

We concluded that the in vitro expression of serotonin can be modulated by environmental factors, but the relative influence of these factors is very different in rostral versus caudal serotonin expressing cell populations.
Monoclonal antibody Br4 recognizes specific neuronal celltypes
Authors: Saito Mitsuo , Saito Mitsuo
Published: January 2005

A monoclonal antibody termed as Br4 was prepared by a fusion of the myeloma P3 x 63‐AG8‐653 with spleen cells from BALB/c mice immunized with chick embryonic brain cells. Immunocytochemically, it reacts strongly with certain neurons in cerebral cortex, hippocampus, substantia nigra, and granular layer of cerebellum from rat brain but does not react with the white matter, A monoclonal antibody Br4 also reacts with primary cultured chick neurons, but not with cultured astrocytes. Western blots show that Br4 recognizes three proteins of 145,000, 108,000, and 97,000 molecular weight from the rat brain. The protein with molecular weight 145,000 (p145) and the protein with 97,000 molecular weight (p97) are essentially soluble; p145 is especially enriched in the synaptosomal soluble fraction. The protein with 108,000 molecular weight (p108) is found in both membranebound and soluble forms. Western blots show that among the tissues examined the three proteins are found most abundant in brain and especially enriched in the cerebral cortex and hippocampus. The Br4 antigens may be useful in identifying neuronal cell subpopulations in the central nervous system.
Substance P gene expression is regulated by interleukin‐1 in cultured sympathetic ganglia
Authors: Hart R. P. , Shadiack A. M. , Jonakait G. M.
Published: January 2005

We have investigated the effects of interleukin‐1β (IL‐1β) on the induction of substance P (SP) in cultured sympathetic ganglia. Northern blot analysis reveals that SP increases are secondary to an increase in mRNA coding for the preprotachykinin (PPT) precursor of SP. Nuclear transcription assays detect an early increase in PPT‐specific nascent transcripts, suggesting that the ultimate effect of IL‐1 is on transcription itself. Depolarizing agents, interferon‐γ glucocorticoid hormones, and prostaglandin synthesis inhibitors all diminish the induction of SP and PPT mRNA by IL‐1. Since SP has stimulatory effects on the immune system, the IL‐1–induced increase in ganglionic SP may be one means by which the nervous and immune systems interact during an acute response to ganglionic injury.
Protein kinase C‐induced redistribution of the cytoskeleton and phosphorylation of vimentin in cultured brain macrophages
Authors: Ciesielski‐Treska J. , Ulrich G. , Aunis D.
Published: January 2005

The phorbol ester 12‐O‐tetradecanoyl‐acetate (TPA) induced prominent and transient changes in the organization of the cytoskeleton in cultured amoeboid microglial cells including redistribution of actin toward the center of the cells and in the subplasmalemmal region, appearance of fine actin filaments, retraction of micro tubules (MT), and rearrangement of intermediate filaments (IF) containing vimentin. The possible implication of protein kinase C (PKC) in mediating the effects of TPA was suggested by a parallel shift of PKC activity from the soluble to membrane fractions and phosphorylation of several microglial proteins.

The rearrangement of IF closely correlated with increased vimentin phosphorylation, detected by pulse labeling of intact cells. Two monoclonal antivimentin antibodies, B3 and V9, showed different staining patterns. Immunoreactivity with the antibody B3 was more restricted and could be abolished by treatment of fixed, permeabilized cells with alkaline phosphatase, thus suggesting that the antibody reacts with a phosphorylated epitope. Using this antibody, rearrangement of IF involving vimentin phosphorylation was detected within 15 to 60 min of treatment with 50 nM TPA and consisted in the appearance of intense perinuclear fluorescent label. This perinuclear fluorescence persisted up to 24 hr after TPA removal and gradually diminished during the following 2 to 3 days. Immunochemical analysis of nonionic detergent‐soluble and ‐insoluble extracts from untreated and TPA‐treated cells revealed no differences in vimentin solubility suggesting that TPA induced vimentin phosphorylation does not result in notable vimentin filament disassembly. However the extent of vimentin degradation was more prominent in TPA‐treated cultures indicating a higher sensitivity of vimentin to proteolytic degradation.

The data show that PKC‐mediated phosphorylation of vimentin results in precise spatial and temporal rearrangement of IF which are not associated with altered vimentin solubility, but possibly changes the mechanical properties and interactions of vimentin filaments.
Cloning of a human cDNA expressing a high voltage‐activating. Tea‐sensitive, type‐a K+ channel which maps to chromosome 1 band p21
Authors: Rudy B. , Sen K. , De Miera E. Vega‐Saenz , Lau D. , Ried T. , Ward D. C.
Published: January 2005

Over ten different mammalian genes related to the Drosophila Shaker gene (the Sh gene family) have been identified recently. These genes encode subunits of voltage‐dependent K+ channels. The family consists of four subfamilies: ShI genes are homologues of Shaker; ShII, ShIII, and ShIV are homologues of three other Shaker‐like genes in Drosophila, Shab, Shaw, and Shal, respectively We report here the cloning of a human K+ channel cDNA (HKShIIIC) obtained from a brain stem cDNA library. HKShIIIC transcripts express an atypical voltage‐dependent transient (A‐type) K+ current in Xenopus oocytes. This current is activated by large membrane depolarizations and is extremely sensitive to the K+ channel blocker TEA unlike most A‐type currents. The gene encoding HKShIIIC maps to chromosome 1p21.
Sequence of the rabbit neurofilament protein L
Authors: Soppet D. R. , Beasley L. L. , Willard M. B.
Published: January 2005

In the course of screening a rabbit brain cDNA library with a probe for the H neurofilament protein, we identified a neurofilament L‐cDNA. Its nucleotide sequence is 88% identical to that of human, indicating that L is highly conserved among species. The similarities between the sequences of L from rabbit and mouse suggest that the species‐specific accumulation of neurofilaments that occurs in rabbit during aluminum intoxication is not a consequence of the primary structure of L.