bluuebunny/crossref_metadata_2025 huggingface dataset:
Hippocampal glutamate release after porta cava anastomosis: Reduced sensitivity to ammonia inhibition
Authors: Hamberger Anders , Hedquist Bo , Lundborg Hugo , Nyström Britta
Published: January 2005

In vitro measurements of basal efflux and evoked release of exogenous and endogenous glutamate from rat hippocampus showed that exposition of the tissue to pathophysiological concentrations of ammonium chloride (3 mM) for 40–60 min abolished the KC1‐induced release of endogenous glutamate. Basal efflux of endogenous glutamate was elevated by ammonium chloride with a delay of 30–40 min.

In an attempt to link these observations to the pathogenesis of hepatic coma, rats were subjected to porta‐cava anastomosis, and the hippocampal tissue was tested for ammonia sensitivity 3–4 weeks after the operation. The results showed that ammonia perfusion of the tissue was without effect on either basal or KCl‐evoked release of endogenous glutamate. In addition, the utilization of glutamine for glutamate formation was influenced in hippocampal but not cortical tissue form porta‐cava anastomized rats. The results suggest that ammonia is an important factor for the disturbed metabolism of the neurotransmitter pool of glutamate in hepatic failure.
Effect of peptides of bovine myelin basic protein on dermal fibroblasts
Authors: Chiang T. M. , Whitaker J. N. , Seyer J. M. , Kang A. H.
Published: January 2005

Bovine basic protein (BP) was digested with purified bovine brain cathepsin D to produce well defined BP derived peptides 1–42, 43–88, 43–169, and 89–169. BP and these BP peptides were tested for their effects on cultured human dermal fibroblasts using a concentration range of 0.01–1,000 ng/ml. No effect was found on cellular proliferation, and neither total protein nor collagen synthesis was altered in the presence of these substances. Although preparations of brain which contain a fibroblast‐growth factor also contain BP peptides, these results indicate that the purified BP peptides studied have no detectable biological effect on the growth of human dermal fibroblasts.
Ultrastructural differentiation and synaptogenesis in aggregating rotation cultures of rat cerebral cells
Authors: Lu Elizabeth J. , Brown W. Jann , Cole Ruth , deVillis Jean
Published: January 2005

Cerebral cortices from fetal rats were dissociated into single cells by either trypsinization or mechanical sieving. Then the cells were allowed to form aggregates in rotation cultures. At 7, 14, 21, 28, and 35 days, aggregates were processed for electron microscopic study of morphological differentiation with special emphasis on synaptogenesis.

Whether the tissue was initially dissociated by trypsin treatment or by mechanical sieving, the aggregating cultures did not exhibit any apparent differences in ultrastructural differentiation and synaptogenesis. At day 7, most neurons were immature and the extracellular space was large. Cell processes had not yet branched extensively but did contain numerous microtubules. A few immature synapses were observed. Astrocytes and oligodendrocytes displayed many of their typical cytological features. At day 14, dendritic spines had developed, some of which formed axodendritic spinous synapses. Multilayered myelin sheaths were tightly wrapped around axons. At day 21, synapses appeared mature and their number per unit area was maximal. The extracellular space had greatly decreased. At this age, asymmetrical synapses had increased approximately sixfold, whereas symmetrical synapses increased only fourfold when compared with the 7‐day‐old aggregates. Multifocal degeneration became apparent at 28 days and was accompanied by a significant decline in the number of synapses.
Inhibition of cyclic nucleotide accumulation following hippocampal tetanic potentiation: Effects of diazepam
Authors: Clement‐Cormier Yvonne , DeFrance Jon , Divakaran Putevah , Stanley James , Taber Katherine , Marchand James
Published: January 2005

Biochemical studies on the hippocampus of acutely prepared rabbits revealed more than two fold increases in cyclic GMP levels following tetanic potentiation of the pathway from the medial septal region to CA1 pyramidal cells. Diazepam, administered intravenously, prevented the elevation in cyclic GMP levels in this region and also attenuated the post‐tetanic potentiation seen following the presentation of trains at frequencies within theta rhythm. The results imply a modulatory role for cyclic nucleotides in the enhancement of pyramidal cell excitability and suggest that the biochemical mechanism for the psychoactive benzodiazepines may well include the suppression of cyclic GMP levels.
Drug‐induced changes in catecholaminergic cells of the fish retina
Authors: Negishi K. , Laufer M. , Drujan B. D.
Published: January 2005

The changes in fluorescence intensity and number of visible catecholaminergic cells (CA‐cells), as revealed by means of a histofluorescence technique, were used as indicators of the effects of various pharmacological agents upon CA‐cells in the retina of fishes (Cyprinus carpio and Eugerres plumieri). The study includes in vivo and in vitro experiments. In the in vivo experiments, intravitreal injection, two or three hours before eye enucleation, of 10 μg L‐DOPA, dopamine, or noradrenaline accentuated CA‐cell fluorescence and increased the number of visible cells, whereas 10 μg of tyramine, octopamine, synephrine, or adrenaline reduced the endogenous fluorescence. Intramuscular injection of reserpine (3 mg/kg) abolished CA‐cell fluorescence. In the in vitro experiments, pieces of isolated retinas were incubated for three or 30 minutes in media containing different drugs. Only minor changes in fluorescence were detected after three minutes of incubation, but after 30 minutes, dopamine (20 μM) markedly enhanced CA‐cell fluorescence. Carbachol (20 mM), acetylcholine (10 mM) plus BW‐anticholinesterase (1 mM) or substance P (1.6 × 10−2 mM), all reduced CA‐cell fluorescence. Kainic acid (20 μM) abolished fluorescence from CA‐cell somata, while fluorescent fiber networks remain unchanged. L‐aspartate (5 mM) and GABA (10 mM) in the incubation medium did not influence fluorescence intensity. The results are relevant to, and consistent with, electrophysiological observations of dopamine‐mediated spatial effects on horizontal cell potentials.
A new antigen common to the rat nervous and immune systems: II. Molecular characterization
Authors: Rodman Jane Somsel , Akeson Richard
Published: January 2005

G5‐IgG is a monoclonal antibody that binds specifically to some cells and tissues of the adult rat nervous and immune systems. The molecular nature of the G5 antigen from adult rat brain is described in this paper. G5 antigen in adult rat brain membrane fractions was trypsin‐sensitive and heat‐labile but not chloroform/methanol‐soluble. It was solubilized by the nonionic detergent NP40 but not by 3 M KCl. Detergent‐soluble rat brain particulate protein inhibited G5‐IgG binding to glutaraldehyde‐fixed rat brain particulate protein. Inhibitory activity could be removed by prior incubation with concanavalin‐A agarose beads. Immunoprecipitates of enzymatically iodinated, detergent‐solubilized brain particulate protein gave a single band on polyacrylamide gels of apparent molecular weight 95,000–105,000 daltons. A band of identical molecular weight was visualized in gels of unlabeled immune precipitates by 125I‐concanavalin A. These results strongly suggest that G5 is an integral membrane glycoprotein in adult rat brain.
Long‐term intracellular retention of hexosaminidase A by Tay‐Sachs disease brain and lung cells in vitro
Authors: Brooks Steven E. , Hoffman Linda M. , Amsterdam Daniel , Adachi Masazumi , Schneck Larry
Published: January 2005

Enzyme‐replacement treatment for metabolic storage disorders has been widely studied using model cell culture systems. This study determines the long‐term fate of human hexosaminidase A supplied to Tay‐Sachs disease brain and lung cells. Hex A retention studies showed that the incorporated Hex A is retained in undiminished quantity by TSD lung cells maintained in stationary culture for 14 days. Tay‐Sachs disease brain cells similarly followed for 28 days in stationary culture showed an initial reduction in Hex A for 3 days, after which the Hex A level stabilized and remained relatively constant for the next 25 days. Hexosaminidase B isoenzyme was found to accumulate in both cell lines during extended cultivation, despite the observation that significant amounts were excreted into the extracellular environment. The demonstration of long‐term intracellular retention of exogenously supplied therapeutic enzyme by the target cells offers additional evidence for the feasibility of an enzyme‐replacement approach for study and treatment of lysosomal storage disorders.
Detection of antibodies to central nervous system antigens by solid phase radioimmunoassay
Authors: Linthicum D. Scott , Mackay Ian R. , Wilson Anne , Horvath Leonie B. , Carnegie Patrick R.
Published: January 2005

A solid phase radioimmunoassay is described which employs 125I‐protein‐A to detect the presence of antibodies against a panel of cellular and soluble central nervous system (CNS) specific antigens coated onto polyvinylchloride Microtiter plates. Serum antibodies from rabbits immunized against myelin, myelin basic protein (MBP), glial acidic fibrillary protein (GFAP), astroglioma cells, and cerebellar cells were easily detected, and high specificity for each antiserum and antigen was also demonstrable. The assay is applicable to cerebrospinal fluid (CSF) from patients with neurological diseases to detect antibodies against CNS‐specific antigens. The assay should be useful for examining cell lines derived from CNS tissue for the presence of brain proteins.
Development and aging of noradrenergic cell bodies and axon terminals in the chicken
Authors: Yurkewicz Lorraine , Marchi Mario , Lauder Jean M. , Giacobini Ezio
Published: January 2005

Tyrosine hydroxylase activity was measured in the region of locus coeruleus, cerebellum, cervical spinal cord, lumbar sympathetic ganglia, and iris throughout most of the life span of the chicken (8 days of incubation to 5 years) to compare developmental trends in tyrosine hydroxylase activity in noradrenergic cell bodies and in axon terminals in both the central and peripheral nervous system. Fluorescence histochemistry and retrograde transport of horseradish peroxidase were used to characterize further the coeruleo‐cerebellar projections. Tyrosine hydroxylase activity was detected in the cerebellum as early as 8 days of incubation, which is the earliest stage so far reported. The greatest increase in total tyrosine hydroxylase activity in the region of the locus coeruleus and cerebellum occurred during the embryonic period. There was a more pronounced increase in the cerebellum than in the locus coeruleus region. This is in contrast to the cervical spinal cord where tyrosine hydroxylase activity increased at approximately the same rate during the embryonic and post‐hatching periods. Moreover, the cerebellum and cervical spinal cord, two locus coeruleus target sites, displayed different trends in tyrosine hydroxylase activity throughout development and aging.

In both structures examined in the peripheral nervous system, the greatest increase in total tyrosine hydroxylase activity occurred during the post‐hatching period, with a greater rise in the cell bodies of the lumbar sympathetic ganglia than in the noradrenergic terminals of the iris. In both the central and peripheral nervous system, total tyrosine hydroxylase activity continued to increase in noradrenergic terminals long after hatching reaching the highest levels at 7 months when the chicken is considered fully mature. During aging, 16 months to 5 years, there was a greater decrease in total tyrosine hydroxylase activity in the terminals of noradrenergic neurons than in the cell bodies in both the central and peripheral nervous system, a phenomenon that was more marked in the peripheral nervous system than in the brain.
Effect of morphine on catecholamine‐stimulated cyclic AMP production in cortex slices from rats and mice
Authors: Slater P. , Blundell C.
Published: January 2005

Morphine (10 μM) blocked noradrenaline‐stimulated cyclic AMP production in slices of cerebral cortex from normal rats but not in slices from rats pretreated with 6‐hydroxydopamine (6‐OHDA). In contrast, morphine failed to prevent noradrenaline‐stimulated cyclic AMP production in mouse cortex slices. Levorphanol weakly antagonized the rise in cyclic AMP produced by noradrenaline in both normal and 6‐OHDA‐treated mouse cortex. Morphine had no effect on the adrenaline‐stimulated cyclic AMP accumulation in mouse cortex but it entirely prevented the rise in cyclic AMP produced by isoprenaline. This effect was not observed in brain slices from 6‐OHDA‐treated mice. It is concluded that in slices of rat cortex, morphine stimulates postulated presynaptic, 6‐OHDA‐sensitive, opiate receptors associated with noradrenergic nerve terminals. These opiate receptors alter postsynaptic α‐ and β‐adrenoceptor activity. In the mouse, morphine appears to stimulate presynaptic opiate receptors that modify exclusively β‐adrenoceptor‐mediated cyclic AMP production.
Exaggerated cyclic AMP accumulation and glial cell reaction in the cerebellum during Purkinje cell degeneration in pcd mutant mice
Authors: Ghetti Bernardino , Truex Lewis , Sawyer Barry , Strada Samuel , Schmidt Michael
Published: January 2005

The Purkinje cell degeneration mutant (pcd) is characterized by a complete loss of cerebellar Purkinje cells. Norepinephrine causes an accumulation of cyclic AMP in the cerebellum of pcd that is far greater than in normal mice. Experiments were conducted (1) to correlate changes in the cyclic‐nucleotide response with a histologic examination of the cerebellum during neuronal loss and (2) to examine the role of cyclic AMP catabolism and adenosine receptor interactions in the phenomenon. The greatest elevation in cyclic AMP occurred between 30 and 128 days of age when a severe astrocytic response was demonstrated throughout the cerebellar cortex. Purkinje cells had degenerated by 45 days of age. Norepinephrine elicited a smaller increase in cyclic AMP from 155‐day‐old mice than at earlier ages, and the response continued to decrease with age; at 270 days, equal accumulation, and at 365 days, lower accumulation of cyclic AMP was detected in pcd cerebella. During this time, the Purkinje cell debris had been removed, the granule cell layer was depleted of granule cells, and the molecular layer was deprived of a large number of parallel fibers. However, although phagocytosis of neuronal debris was completed, large numbers of astrocytic processes were still seen in the neuropil.

Biochemical experiments in vitro established that the exaggerated accumulation of cyclic AMP in the presence of norepinephrine was not due to lower catabolism of cyclic AMP, a synergistic interaction with adenosine, or a result of lower protein in the pcd cerebellum. The correlates of heightened norepinephrine‐stimulated accumulation of cyclic AMP with neuronal loss and the glial cell reaction might indicate that cyclic nucleotides play a role in controlling some glial cell functions, ie, proliferation, migration, and phagocytosis.
Electroblot analysis of the myelin proteolipid protein
Authors: Macklin Wendy B. , Braun Peter E. , Lees Marjorie B.
Published: January 2005

The myelin proteolipid has been studied by the electroblot method of Towbin et al [1979]. Samples were separated by SDS–polyacrylamide gel electrophoresis, transferred to nitrocellulose, and incubated with proteolipid antibody. The proteolipid band could be identified immunologically in CNS myelin and in whole brain homogenates. No proteolipid was detected in PNS myelin. Proteolipid from human, bovine, rat, and mouse myelin all cross‐react when analyzed by this method. No cross‐reactivity was indicated between proteolipid and myelin basic protein.
Effects of methadone on ornithine decarboxylase and cyclic nucleotide phosphohydrolase in neuronal and glial cell cultures
Authors: Vernadakis Antonia , Estin Charles , Gibson D. Ann , Amott Susan
Published: January 2005

Mixed neuronal and nonneuronal cell cultures were obtained from 8‐day‐old chick embryos cerebral hemispheres and glial‐enriched cultures were obtained from fifteen‐day‐old chick embryo cerebral hemispheres. Cultures were exposed to methadone, a narcotic drug, from days four to six. The activity of ornithine decarboxylase (ODC) was determined at day eight and the activity of cyclic nucleotide phosphohydrolase (CNP) was determined at day fifteen. Both ODC and CNP activity were higher in mixed neuronal‐nonneuronal cell cultures treated with methadone as compared to control. No effect was observed in the neuronal‐enriched or glial‐enriched cultures. These findings are interpreted to reflect that neuronal‐glial interaction is important in the response of primary neural cells to methadone.
Inhibitory action of high formamide concentrations on excitation‐contraction coupling in skeletal muscle
Authors: de Motta Gladys Escalona , Códoba F. , de León M. , del Castillo J.
Published: January 2005

Strips of guinea pig ileum lose over 70% of their contractility when bathed in Krebs‐Ringer solution containing 0.4–0.9 M formamide (FMD). This effect is not accompanied by an appreciable loss of tissue water and is totally reversed by washing the preparation in normal solution. Frog sartorius muscles also paralyze when immersed in Ringer containing FMD, but higher concentrations (1.0–2.0 M) and longer exposure times are required. Contractility is not recovered upon transferring these muscles to normal Ringer. However, the contractile proteins still respond to activator calcium as shown by the fact that these muscles still contract in the presence of caffeine. The membrane of muscles uncoupled by FMD retain electrical excitability, and neuromuscular transmission appears to be unimpaired. However, alterations in the early after‐potential of the spikes suggest the occurrence of a sarcotubular disruption. Therefore, FMD appears to exert two separate effects on muscle: a reversible inhibition of contractility, as observed in ileal strips and an irreversible blockade due to an osmotic shock observed when frog muscles are returned to normal Ringer. The reversible effect is probably related to interference with the availability of activator calcium, since no marked inhibitory effects on the activities of the actomyosin‐like and the calcium‐dependent and ‐independent ATPases could be observed on FMD‐treated subcellular fractions.
Effect of phospholipase A2 on calcium transport in brain synaptosomes
Authors: Noremberg Krystyna , Łazarewicz Jerzy W.
Published: January 2005

Pretreatment of isolated brain synaptic endings with commercial phospholipase A2 isolated from venom of Apis mellifera, followed by a BSA washing, selectively inhibited the depolarization‐dependent portion of 45Ca uptake.

Phospholipase A2 initially caused an increase of synaptosome respiration and subsequently inhibited their oxygen uptake, but this effect was completely abolished in BSA‐containing media.

The classical uncoupler of oxidative phosphorylation, DNP, produced release of 45Ca or [3H]GABA from superfused synaptosomes previously loaded with radioactive calcium or GABA. The treatment of synaptosomes with phospholipase A2 had no effect on the spontaneous efflux of 45Ca or [3H]GABA. However, depolarization‐dependent release of [3H]GABA from synaptosomes treated with phospholipase A2 was significantly inhibited.

We suggest that the inhibition of depolarization‐dependent influx of 45Ca into synaptosomes treated with phospholipase A2 may be attributed to the lesion of the specific function of plasma membrane rather than to the impairment of the calcium‐sequestrating function of intraterminal structures.
Kanic acid alters cholinergic responses in the rat retina: A 2‐deoxyglucose study
Authors: Gomez‐Ramos P. , Nelson S. , Walter D. , Cross R. , Samson F. E.
Published: January 2005

Intraocular injections of the neuroexcitatory toxin, kainic acid, did not alter the output of the retinal ganglion cells, as determined by the rate of glucose use in the stratum griseum superficialis of the superior colliculus. However, significant differences were observed in cholinergic interactions of the ganglion cells after kainic acid treatment. Intraocular injection of kainic acid prevented the increase in the stratum griseum superficialis activity typically produced by systemic injection of the acetylcholinesterase inhibitor diisopropylfluorophosphate (DFP). In addition, the retinal ganglion cells were strikingly sensitive to intraocular injections of acetylcholine 1 week after exposure to kainic acid, reflected in the marked increased glucose utilization in the stratum griseum superficialis. This responsiveness to acetylcholine may be entirely due to the 80% decrease in acetylcholinesterase in the retina observed 1 week after kainic acid exposure or in part to a supersensitivity of the ganglion cells following the period of acetylcholine depletion.
Presynaptic effects of sodium bisulfite at the frog neuromuscular junction
Authors: Steinacker Antoinette
Published: January 2005

Both spontaneous and evoked transmitter release from the frog neuromuscular junction can be modified by application of sodium bisulfite, a reagent specific for disulfide bonds. An increase in miniature endplate frequency is produced that is not dependent on external calcium, sodium, or presynaptic terminal depolarization. The increased release can be halted by application of the sulfhydryl oxidizing agent DTNB. The response of bisulfite can be prevented by prior treatment of the endplate with acetylcholine or an anticholinesterase. It is concluded that bisulfite produces its effects by acting on a protein in the presynaptic membrane that is involved in regulation of transmitter release.
Cell surface‐mediated cellular interactions: Effects of B104 neuroblastoma surface determinants on C6 glioma cellular properties
Authors: Ciment Gary , de Vellis Jean
Published: January 2005

To study the influence of cell surface‐associated molecules on intercellular communication, C6 glioma cells were cultured both on plastic and on substrata of paraformaldehyde‐fixed B104 neuroblastoma cells. By then comparing the phenotypic expression of these “cocultured” C6 cells with cells cultured on tissue culture plastic, the influence of the cellular substratum was determined.

The beta‐adrenergic‐responsive cyclic AMP‐generating system of C6 cells was compared on these various substrata. We found that fixed beds of dibutyryl cyclic AMP (dbcAMP)‐treated B104 cells uncoupled beta‐receptors from adenylate cyclase, whereas fixed beds of similarly treated C6 cells did not. However, other cellular properties were not affected by growth atop fixed dbcAMP‐treated B104 cell beds including the rate of C6 cellular proliferation and their rate of protein synthesis. The cell surface‐associated determinant on B104 cells capable of uncoupling the beta‐responsive cyclase system of C6 cells is probably a protein, as judged by its susceptibility to protease treatment.

Other properties of C6 cells were also affected by the various substrata including basal and hydrocortisone‐induced levels of glycerol phosphate dehydrogenase (GPDH; an oligodendroglial marker) and the rate of RNA synthesis in these cells.
The ratio of 3‐hydroxyacyl‐CoA dehydrogenase to lipoamide dehydrogenase activity in individual muscle fibers: Mitochondrial specialization for source of energy
Authors: Hirsch Hilde E. , Parks Mary Ellen , Blanco Cesar E. , Simpson Donald R.
Published: January 2005

3‐Hydroxyacyl‐CoA dehydrogenase (HAD) has been widely used to assess the capacity for fatty acid oxidation by different muscle fiber types, with various Krebs cycle enzymes as a base for comparison. We have measured this enzyme in individual lyophilized fibers of the guinea pig soleus and the white and red portions of the vastus lateralis, and compared its activity in each fiber with that of lipoamide dehydrogenase (LAD), which as a part of the pyruvate dehydrogenase complex fulfills a function similar to HAD in forming acetyl‐CoA, but from pyruvate and, thus, mainly from a carbohydrate source. The mean HAD/LAD ratio was 17.2 ± 3 in the red vastus, 24.9 ± 3 in the white vastus, and 43.7 ± 10 in the soleus, all differences being highly significant. The two types of fast fibers were not distinguished from one another by the enzyme ratio within either the white or the red portion of the vastus lateralis. Data from all of the fast fibers taken together indicate a close correlation (0.93) between the two enzymes, whereas values from the soleus indicate a specialization of the mitochondria of the slow muscle fibers for the oxidation of fatty acids.
Gonadal influences on the inhibition of monoamine oxidase type B activity
Authors: Vaccari Andrea , Biassoni Roberto
Published: January 2005

Monoamine oxidase type B (MAO‐B) was similarly active in the hypothalamus of 60‐day‐old male and female Charles River rats. A single, 2 mg/kg IP injection of deprenyl, however, resulted in a significantly greater inhibition of hypothalamic MAO‐B in normal males than in normal females. Repeated administration of estrogen (estradiol valerate) to intact males postnatally, a treatment which disrupts the masculinization process, although not provoking true “feminization,” decreased the inhibition of MAO‐B, thus abolishing the sex‐specific difference. The intensity of deprenyl‐provoked hypothermia and ptosis in males exceeded that of females; neonatal and postnatal estrogenization of males resulted in diminution of these effects. Androgen administration to neonate females did little affect the biochemical and in vivo parameters of MAO inhibition. It is concluded that sex‐specific, biochemical differences in MAO‐B inhibition may have pharmacological correlates, and both facets of MAO inhibition are sensitive to neonatal exposure to estrogen.
Tay‐Sachs disease and normal cerebellar cells in culture: Elevated levels of lysosomal enzymes in Tay‐Sachs disease cells
Authors: Hoffman Linda M. , Brooks Steven E. , Schneck Larry
Published: January 2005

Tay‐Sachs disease and normal fetal cerebellar cells were maintained in culture for up to four weeks. Elevated levels of the lysosomal enzymes hexosaminidase B, β‐galactosidase, and acid phosphatase were observed in the Tay‐Sachs cells in long term cultures although elevated lysosomal enzyme levels were not observed in the normal cultures. Similarly, elevated lysosomal enzyme activities were observed in Tay‐Sachs cultures which had been treated with Concanavalin A.
ATPase activities in myelin and oligodendrocytes isolated from the brains of developing rats and from bovine brain white matter
Authors: Zimmerman Thomas R. , Cammer Wendy
Published: January 2005

Of the Na, K‐ATPase activity in brain homogenates from 20‐, 60‐, and 120‐day‐old rats, 1.4 to 2.6% was recovered in myelin. The relative specific activities, at 0.2 to 0.3 times the specific activities in the rat brain homogenates, did not decrease during development, and myelin from bovine brain white matter had a similar relative specific activity. Oligodendrocytes from rat brains and bovine white matter had approximately one third the Na, K‐ATPase specific activities found in myelin from the respective sources. The Mg‐ATPase activity in rat brain myelin decreased during development and, in myelin from adult rats, was much lower than the Na, K‐ATPase activity. Notably, oligodendrocytes from both the forebrains of 10‐ to 120‐day‐old rats and from bovine white matter had high Mg‐ATPase activities. Whereas Na, K‐ATPase may be intrinsic to certain regions of the myelin sheath, the Mg‐ATPase in isolated myelin probably arises from fragments of oligodendrocyte membranes.
Maternal ethanol consumption and synaptic membrane glycoproteins in offspring
Authors: Noronha Antonio B. , Druse Mary J.
Published: January 2005

The present study was undertaken to assess the influences of chronic maternal ethanol consumption, prior to and during gestation, on the development of synaptic plasma membranes (SPMs) and on the synthesis of SPM glycoproteins in offspring. Comparisons were made between animals whose mothers were pair‐fed a control or 6.6% (v/v) ethanol liquid diet in which protein accounted for either 18% (original) (C & E) or 21% (revised) (*C & *E) of the calories. In addition, groups of pups that were either cross‐fostered (*C & *E) with chow‐fed surrogate mothers or reverse cross‐fostered (offspring of chow‐fed mothers with *C & *E mothers) were examined. Ethanol and matched (same dietary group) control pups had comparable brain and body weights, brain protein content, and yield of SPM proteins during the 10–24 day age period examined. However, the yield of SPM proteins from ethanol and control offspring of and/or reared by the three groups of rat mothers that received the *E and *C liquid diets was greater than that of the offspring of rats that were fed the original diets. This suggests that the original diets were not nutritionally adequate for pregnant rats. Despite the fact that the content of SPM proteins was comparable in ethanol and matched control pups, the offspring of ethanol‐treated rats had an abnormal distribution of [3H]‐or [14C]‐fucose‐derived radioactivity among SPM glycoproteins. The SPM abnormalities were most severe in the non‐cross‐fostered offspring of E rats. No SPM glycoprotein abnormalities were found in the reverse cross‐fostered group. The results of the present study demonstrate that chronic maternal ethanol consumption prior to parturition has a severe effect on the synthesis of SPM glycoproteins in developing offspring without affecting the content of SPMs per se. It also demonstrates the importance of optimizing the composition of liquid diets used to feed pregnant rats.
Nerve growth factor: Subunit interactions in the mouse submaxillary gland 7S complex
Authors: Silverman Robert E. , Bradshaw Ralph A.
Published: January 2005

Sedimentation velocity analyses of the isolated subunits of mouse 7S nerve growth factor (NGF) and their binary complexes have been performed. The 2.5S (β) form of NGF binds 2 α subunits independent of the presence of γ subunits. Two γ subunits are also complexed by 2.5S NGF; however, this interaction is dependent on the presence of a carboxyl terminal arginine residue on the β polypeptide chain. The partial loss of this residue in 2.5S NGF preparations results in a ternary complex(es) with a reduced sedimentation coefficient(s). The two binary complexes formed (α2‐β and β‐γ2) show markedly different pH stability profiles. The α and γ subunits do not form a demonstrable complex, but apparently can interact in the ternary complex to render it more stable than the sum of the α‐β and β‐γ interactions.
Characteristics of the association of nerve growth factor with primary cultures of rat sympathetic neurons
Authors: Hawrot Edward
Published: January 2005

Long‐term primary cultures of rat sympathetic neurons require NGF for survival and development. The kinetics of the interaction of 125I‐NGF with sympathetic neuron cultures suggests the presence of diffusional barriers preventing a determination of true dissociation and association rate constants. Although the observed rate constants do not accurately reflect the microscopic interaction of NGF with receptor, the ratio of the observed rate constants does provide a good estimate of the KD. This value (1 × 10−9M) agrees with earlier steady state measurements of the KD. The association of 125I‐NGF with neuronal cultures is temperature‐dependent with internalization and retrograde transport occurring at 37°C. The retrograde transport of 125I‐NGF in compartmentalized neuronal cultures is concentration dependent and saturates at about 100 ng/ml (4 × 10−9M). The amount of 125I‐NGF accumulated by retrograde transport appears to be increased subsequent to a period of NGF‐starvation. The increase in uptake does not appear to be due to an increase in NGF receptor number since the number of binding sites is not greatly increased upon NGF starvation.
Comparative features of spinal neuronotrophic factors in fluids collected in vitro and in vivo
Authors: Manthorpe Marston , Longo Frank M. , Varon Silvio
Published: January 2005

Survival in monolayer culture of 4‐day (stage 23) chick embryo lumbar spinal cord neurons can be regulated by two opposing activities. One, spinal neuronotrophic activity, promotes neuronal survival; and the other, spinal neuronotoxic activity, eliminates the neurons from the culture even when the trophic support is present at an optimal concentration. Quantitative microbioassays for each activity are presented and used to measure the relative amounts of each agent within different sources including glial, muscle, and spinal cord cell‐conditioned media and fluid collected from peripheral and central nervous tissue lesions. Although both activities were present in all of the sources tested, their concentrations in the wound fluids were orders of magnitude greater than in the conditioned media. The fluid‐derived trophic activities were inactivated by heat and trypsin and nondialyzable, whereas all of the conditioned media‐derived trophic activities were heat‐ and trypsin‐resistant and dialyzable.
Cultures of zona ependyma cells of goldfish brain: An immunological study of the synthesis and release of ependymins
Authors: Majocha R. E. , Schmidt R. , Shashoua V. E.
Published: January 2005

Two proteins (ependymins β and γ) localized within specific cells in the zona ependyma of goldfish brain were identified in previous studies in our laboratory as extracellular factors whose metabolism was highly increased by the acquisition of new patterns of behavior. Methods for growing zona ependyma cells in culture were developed to determine if cells within this tissue could synthesize and release the ependymins into their extracellular environment. Dissociated cells from zona ependyma were grown as primary monolayer cultures on polylysine‐coated slides. The cultures survived for at least 4–5 weeks, forming an intricate network of interconnecting processes. These contained many cell types, several of which retained their in vivo immunohistochemical properties. Specific populations of cells staining with antisera to nerve growth factor, glial fibrillary acidic protein, and ependymins β and γ were present. Radioimmunossay, immunoelectrophoresis data, and labeling experiments indicate that cells within the cultures can synthesize the ependymins de novo and release them into their extracellular environment. These results are consistent with the hypothesis that the ependymins might function as extracellular factors which mediate the behaviorally induced plasticity of the goldfish CNS. In this respect they resemble other “protein factors” which stimulate the growth and morphological differentiation of nervous system cultures.
Failure of nerve growth factor to enhance wound healing in the hamster
Authors: Leitzel Kim , Cano Cheryl , Marks James , Lipton Allan
Published: January 2005

We have investigated the effect of topically applied high molecular weight nerve growth factor (HMW‐NGF) and 7S nerve growth factor (7S NGF) on healing of full‐thickness skin wounds in the Syrian hamster. Our results indicate that HMW‐NGF and 7S NGF have no significant influence on the rate of wound contraction or on the time to complete healing in this animal model.
Regulation of the proliferation of embryonic chick leptomeningeal cells in vitro by both contact inhibition and co‐culture with CNS neurons
Authors: Partlow Lester M. , Hanson Glen R. , Iversen Patrick L.
Published: January 2005

Cultures of leptomeningeal cells (LMCs) isolated from the pia‐arachnoid membrane of 10‐day chick embryos were studied in order to elucidate the mechanisms which regulate the proliferation of these embryonic nonneuronal cells. Thymidine incorporation was quantified in LMC cultures of varying density and in co‐cultures containing both LMCs and neurons. The following results were obtained. First, proliferation of LMCs was very sensitive to contact inhibition. Second, proliferation was also inhibited by co‐culture of leptomeningeal cells with neurons isolated from either the cerebral hemispheres or optic lobes. Third, co‐culture with sympathetic neurons isolated from the peripheral nervous system did not inhibit LMC proliferation; thus, the inhibition resulting from co‐culture with neurons exhibits some regional specificity. Fourth, proliferation of the leptomeningeal cells was inhibited by addition of the sonicate of either cerebral neurons or LMCs but stimulated by addition of the sonicate of sympathetic neurons.

The effect of addition of varying numbers of either intact or sonicated cerebral neurons on thymidine incorporation by cerebral glial cells was also examined. Addition of intact cerebral neurons stimulated cerebral glial proliferation at all concentrations. In contrast, addition of sonicate of cerebral neurons stimulated proliferation at low concentrations but inhibited it at high concentrations. Since addition of intact cerebral neurons inhibits the proliferation of leptomeningeal cells under the same conditions which stimulate the proliferation of cerebral glial cells, these neurons might play a complex role in orchestrating the proliferation of nonneuronal cells during development of the brain.
Catecholamines in rat brain following postnatal undernutrition and nutritional rehabilitation
Authors: Wiggins Richard C. , Fuller Gregory N. , Seifert William E. , Butler Ian J. , Gottesfeld Zehava
Published: January 2005

Norepinephrine and dopamine were examined in 19 discrete brain areas from the telencephalon, diencephalon, and mesencephalon of nutritionally rehabilitated adult rats following postnatal undernutrition from birth through 21 days of age. Following rehabilitation, catecholamine levels were not significantly different from control values in any of the areas examined. Catecholamine concentrations in young, undernourished rats are generally elevated (either from stress or from nutritional insufficiency). Data presented here show that whichever case is true, the early effect of undernourishment is transient and that normal values are restored by nutritional rehabilitation.
Muscarinic cholinergic binding in chick embryo retino‐tectal system: Effects of corticosterone
Authors: Gremo Fulvia , Vernadakis Antonia
Published: January 2005

Muscarinic binding sites were measured using the radioligand [3H]quinuclidinyl benzilate (QNB) in the retina and tectum of 11‐day‐old chick embryos, after intracerebral administration of 0.02 μg of corticosterone at 8 days of incubation. This age was chosen because the hormone preferentially accumulates in retinas at 8 days of development. Hormone treatment significantly affected the affinity of 3H‐QNB‐binding sites in retinas and slightly affected the affinity in treated tecta, whereas the number of binding sites remained unchanged. The specific binding was determined with either atropine or unlabeled QNB. Scatchard plot analysis of specific 3H‐QNB binding revealed the presence of nonsaturable binding at high 3H‐QNB concentrations (6‐11 nM) in the treated retinas, but not in controls. It can be concluded from these data that the hormone has a primary effect on retinal cells during early growth in the chick embryo. The possibility that the hormone delays maturation of specific populations of retinal cells is considered in the discussion.
Interaction of manganese with NB41A neuroblastoma adenylate cyclase
Authors: Reiss D. S. , Sapirstein V. S.
Published: January 2005

In vitro assay of the adenylate cyclase of NB41A neuroblastoma cells in the presence of increasing concentrations of MnCI2 suggested that the enzyme is modulated by both high‐ and low‐affinity sites for manganese. MnCI2 in a concentration of 1 μM significantly stimulated adenylate cyclase activity, but increasing the concentration of manganese to 3 μM or 10 μM had no further effect. Raising MnCI2 to 0.1 or 1 mM, however, further stimulated enzyme activity. In addition to differences in affinity for manganese, the two classes of binding sites may be distinguished by differences in their interaction with other agents that affect adenylate cyclase activity. Millimolar manganese and magnesium appeared to compete for a common site on the enzyme and the effect of manganese in this range and the effect of guanyl nucleotide were synergistic. In contrast, the stimulation of activity by micromolar manganese appeared to be additive to the effects of either increasing magnesium or the addition of guanyl nucleotide to the assay media. Comparison of the substrate dependency of the reaction measured in the presence and absence of manganese suggests that the stimulation of adenylate cyclase activity involves increases in both the apparent Vmax of the reaction and the affinity for ATP. The results raise the possibility that the interaction of Mn2+ may play a role in the modulation of adenylate cyclase in vivo.
Long‐term effect of electroshock treatment on the entry of calcium into the cerebroventricular fluid in the rat
Authors: Barkai Amiram I.
Published: January 2005

The rate of appearance (Ra) of calcium (Ca) in the cerebroventricular compartment of urethane‐anesthesized rats was determined by two methods: one is measurement of isotope dilution during ventricular‐cisternal perfusion with artificial cerebrospinal fluid (CSF) containing 45Ca, the other is estimation of the rate of entry of 45Ca from plasma after rapid injection of tracer 45CaCl2 intravenously. Electroshock treatment (EST) for 3 successive days resulted in a marked increase in the rate of entry of calcium from blood to CSF. The effect of EST on the permeability of the blood‐CSF bamer to Ca could be observed even 24 hr after the generalized seizure induced by electroshock has terminated.
Acetylation of polyamines in mouse brain: Subcellular and regional distribution
Authors: Ortiz J. G. , Giacobini E. , Schmidt‐Glenewinkel T.
Published: January 2005

The acetylation of putrescine, cadaverine, spermidine, and spermine was examined in different subcellular fractions and regions of the mouse brain. Acetylation activity was confined to nuclear and microsomal fractions, which can acetylate all of these compounds. These fractions catalyze the formation of N8 but not N1‐acetylspermidine. For the nuclear fraction the Km for putrescine was 3.5 mM; for cadaverine, 4.0 mM; for spermidine, 1.0 mM; and for spermine, 2.5 mM. The Vmax obtained were (pmol/mg protein/10 min): putrescine, 424; cadaverine, 705; spermidine, 239; and spermine, 467.

The acetylation of spermidine was highest in the olfactory bulb and cerebellum. Putrescine and cadaverine acetylation were high in these areas, as well as in the midbrain. Spermine acetylation was rather uniform in all areas examined, except in the brain stem (pons‐medulla) where enzyme activity was very low.
Ion dependency of uptake and release of GABA and (RS)‐nipecotic acid studied in cultured mouse brain cortex neurons
Authors: Larsson O. M. , Drejer J. , Hertz L. , Schousboe A.
Published: January 2005

The influence of sodium ions on GABA uptake into neurons cultured from cerebral cortex was investigated at sodium concentrations ranging from 16 to 151 mM. Sodium did not affect the Km for GABA uptake but the uptake rates as a function of the sodium concentration was sigmoid at all GABA concentrations studied (1‐200 μM). Hill plots of these curves exhibited straight lines with slopes of 1.7‐2.1, suggesting that the coupling ratio between sodium and GABA is at least 2. (RS)‐Nipecotic acid, a GABA analogue, was transported with high affinity (Km 8.0 ± 2.1 μM) like GABA, but the Vmax for nipecotic acid was lower than found for GABA (0.664 ± 2 0.035 versus 0.955 ± 2 0.059 nmol × min−1 × mg−1), suggesting a microheterogeneity of the GABA transport sites. Neurons loaded with the respective vitiated compounds exhibited a pronounced K+‐stimulated, calcium‐dependent release of both GABA and nipecotic acid indicating that these cultured cells have developed functionally active GABA‐ergic synapses.
Cultured neonatal rat oligodendrocytes elaborate myelin membrane in the absence of neurons
Authors: Bradel Edward J. , Prince F. P.
Published: January 2005

We have utilized transmission electron microscopy to study oligodendrocyte‐enriched cell cultures established from dissociated neonatal rat cerebra by the method of McCarthy and de Vellis [1980]. Cells were examined after 14 and 26 days in vitro. The overall morphology of the cells from cultures at both time periods was similar and consistent with previous reports of light (immature) oligodendrocyte fine structure. The cells contained an eccentrically located nucleus, prominent Golgi regions, numerous free ribosomes, and microtubules. Large numbers of processes with varying diameter were also observed. There was some indication of cytoplasmic maturation from the younger to the older cultures. The most important feature of the 26‐day cultures was the large quantity of intercellular membranes which were shown to be continuous with oligodendrocyte processes. There membranes often exhibited the appearance of “loose myelin” and were therefore not normally compacted. Layers of membrane with the morphologic apperance of compact myelin were observed on an occasional oligodendrocyte perikaryon or process. This finding necessitates a reevaluation of the widely held theory that oligodendrocytes are not able to elaborate myelin in the absence of neurons.
Sprouting inducing activity of human sera: Low capacity in sera from patients with cranial polyneuropathy
Authors: Aviel Aaharon , Schwartz Michal
Published: January 2005

Cranial idiopathic acute peripheral facial nerve paralysis (Bell palsy) has been used as a model disease in the present study mainly to investigate trophic capacity of serum components. The ability to induce sprouting from chick embryo dorsal root ganglia was used as the bioassay for trophic activity. Sera from normal patients induce neuritic outgrowth from dorsal root ganglia of chick embryo in the absence of any exogenous factor. Sprouting, to a very limited extent or none, has been induced by 80% of the sera derived from the Bell palsy patients. Further analysis of the biochemical nature of the reduced activity has revealed that in sera of Bell palsy patients the substances that are fractionated within the Ig fraction are responsible for the reduced capacity to induce sprouting without loss of supportive molecules.