bluuebunny/crossref_metadata_2025 huggingface dataset:
Phagocytosis‐mediated retroviral transduction: co‐internalization of deactivated retrovirus and calcium‐alginate microspheres by macrophages
Authors: You Jin‐Oh , Peng Ching‐An
Published: January 2005

Background

Efficiency of retrovirus‐mediated gene transfer has been hampered by short retroviral half‐life due to shedding of retroviral envelope proteins which is of utmost importance to the interaction between retrovirus and cell.

Methods

Calcium‐alginate microspheres with average size of 780 nm were prepared by reverse emulsification and characterized by scanning electron microscopy and microelectrophoresis. To obtain deactivated retroviruses produced from 293 packaging cells, retrovirus‐containing media were pre‐incubated at 37 °C for 6, 12, 18, and 24 h, respectively. Murine J774A.1 macrophages were co‐treated with Ca‐alginate microspheres and deactivated retroviruses encoding the enhanced green fluorescent protein (eGFP) gene. Through phagocytosis, deactivated retroviruses and Ca‐alginate microspheres were co‐internalized into macrophages. After retroviral transduction for 24 and 48 h, the percentages of macrophages with eGFP expression were determined by bright‐field and fluorescence microscopy.

Results

After 48‐h incubation with Ca‐alginate microspheres and deactivated retroviruses, phagosomes turned into large vacuoles occupied almost half of the cytoplasmic space. This was probably attributed to the erosion of Ca‐alginate microspheres by destructive agents within vacuolar compartments and concomitant osmotic swelling. It was reasoned that deactivated retroviruses escaped such enlarged vesicles easily and underwent reverse transcription in the cytosol. The expression of eGFP in macrophages infected by retroviruses pre‐incubated for 24 h in the presence of Ca‐alginate microspheres was thereby augmented up to tenfold in comparison with the cells treated with 24‐h deactivated retroviruses only.

Conclusions

Ca‐alginate microspheres performed as auxiliary agents for the enhancement of retrovirus‐mediated gene transfer efficiency even though retroviruses had been deactivated due to the loss of envelope proteins. Copyright © 2004 John Wiley & Sons, Ltd.
Influence of gonadal steroids on the glial fibrillary acidic protein‐immunoreactive astrocyte population in young rat hippocampus
Authors: Conejo N.M. , González‐Pardo H. , Cimadevilla J.M. , Argüelles J.A. , Díaz F. , Vallejo‐Seco G. , Arias J.L.
Published: January 2005

It is known that expression of glial fibrillary acidic protein (GFAP) as an astrocyte‐specific marker can be regulated by levels of circulating gonadal steroids during postnatal development. In addition, astrocytes play an important role in the physiology of the hippocampus, a brain region considered sexually dimorphic at the neuronal level in rodents. To evaluate the contribution of glial cells to gender‐related differences in the hippocampus, we estimated the number of GFAP‐immunoreactive (GFAP‐IR) astrocytes in the hippocampus (CA1 and CA3 areas, dorsal and ventral regions) of male and female rats aged 30 days. Groups of 30‐day‐old masculinized females (TP‐females; injected with testosterone propionate at birth) and feminized males (FLU‐males, castrated and treated with flutamide, an androgen receptor antagonist) were included to assess the effects of gonadal hormones on these hippocampal astrocytes. Using the optical fractionator method, the total number of GFAP‐IR cells found in CA1 and CA3 areas was significantly higher in males compared to that in age‐matched females. This numerical pattern was reversed in TP‐females and FLU‐males in both hippocampal areas. In addition, more GFAP‐IR cells were found in dorsal hippocampus than in the ventral region in the CA1 area from all experimental groups, whereas this result was found in the CA3 area from males and TP‐females. Our results suggest an essential contribution of gonadal hormones to gender differences found in the astrocyte population of the rat hippocampus during development. © 2004 Wiley‐Liss, Inc.
Cellular compartmentation of brain metabolism and its functional significance
Authors: Rose Steven P. R.
Published: January 2005

This paper reviews work from our laboratory on the metabolism and interrelations of isolated neuronal and neuropil fractions. The cell preparations are evaluated according to criteria of yield, purity, and integrity. Differences in the levels of activity of six groups of enzymes, of glucose metabolism, amino‐acid metabolism, transmitter metabolism, acid hydrolysis, alkaline hydrolysis, and carbonic anhydrase have been followed, and neuronal and glial marker enzymes are proposed. Lysosomes and their enzymes are concentrated in neuronal perikarya. Metabolically, although no major differences in glucose oxidation have been found, there is considerable evidence of compartmentation of amino acids and their metabolism. At short times after injection of 3H‐lysine as precursor in vivo, neuronal incorporation is high as compared with neuropil; at longer times the ratio is reversed, and we interpret this as evidence for the presence of a rapidly labeling protein fraction present in the neuronal perikarya but subsequently transported out. Neuronal protein incorporation is suppressed in the visual but not the motor cortex of dark‐reared rats and is switched on following exposure to light; there is evidence that the suppressed fraction of neuronal protein synthesis includes the rapidly labeling component. A model for neuronal‐glial metabolic interaction and its state‐dependence in response to changes in the organism's environment and behavior is sketched out.
The lipid composition of isolated brain cells and axons
Authors: Norton William T. , Abe Toshiaki , Poduslo Shirley E. , DeVries George H.
Published: January 2005

The current status of the published work on the lipid composition of isolated brain cells is reviewed and some new work on the sphingolipids of these cells is presented. In spite of considerable differences in isolation techniques between different groups, the lipid analyses of different cell preparations are similar enough to permit several generalizations. This fact is an encouraging sign that cell separation methods have considerable usefulness in defining the composition of normal brain cells. It is a general finding that astrocytes have more lipid than neuronal perikarya but that the gross lipid composition of these two cell types is surprisingly similar. Oligodendroglial lipids are quite different from those of the other two cell types and are characterized by a high galactolipid content. Although such a lipid pattern might be expected in oligodendroglia, which are myelin‐forming cells, axonal lipids have an even higher galactolipid content.

In an effort to find more cell‐specific patterns, the glycosphingolipids were examined in more detail. Differences were seen in the distribution and fatty‐acid pattern of these minor lipids in neurons and astrocytes, although it may be premature to conclude that these differences will prove to be cell‐specific. All of the isolated cells were found to contain galactosylceramide, sulfatide, glucosylceramide, dihexosylceramide, and gangliosides. The distribution of these lipids in the normal cells was found to differ considerably from that reported in cultured neuroblastoma cells or astrocytoma cells. Not only were gangliosides present in all cells but the ganglioside patterns of neurons and astrocytes were nearly identical.

The fatty‐acid patterns of the neuronal and astroglial sphingolipids generally do not resemble each other, and both are quite different from those found in oligodendroglia and axons. However, the fatty‐acid composition of the sphingolipids from bovine oligodendroglia and from axons are similar and resemble those of myelin lipids. The fatty acids of glucosylceramide and dihexosylceramide are similar in all three cell types. They have rather large amounts of 16:0 and acids longer then C18; thus they are considerably different from the ganglioside fatty acids (which have mostly 18:0) isolated from the same fractions.
Mesencephalic lesions followed by normophagia but decreased body weight
Authors: Bellinger Larry L. , Bernardis Lee L.
Published: January 2005

Twenty mature male Sprague‐Dawley rats were lesioned in the area of the ascending ventral noradrenergic bundle in the mesencephalon. Nine sham‐operated animals served as controls. Food intake between the lesioned and nonlesioned groups was not significantly different except for the first day post surgery. However, body weight of the lesioned group was significantly below that of the controls when measured 15 days after the operation. The lesioned animals weighed significantly less than the controls throughout the rest of the experiment. They also were hypoactive when compared to the sham‐operated rats. Control rats and lesioned rats did not differ significantly in deep rectal temperature.

It is suggested that the significant decrease in body weight of the lesioned rats in the presence of normophagia may be caused by alterations in the animal's metabolism.
Identity of sensory and motor systems that are critical to the immobility reflex (“animal hypnosis”)
Authors: Klemm W. R.
Published: January 2005

This review presents an analysis of the sensory and motor mechanisms as they are now understood that cause the immobility reflex (IR). Of the sensory systems that conceivably could trigger and sustain the IR, as commonly induced experimentally by inversion and manual restraint, evidence has been presented to eliminate some senses (vestibular, vision, sound, many visceral sensations, olfaction, taste, temperature), while incriminating tactile and proprioceptive influences. Of the motor systems which could cause the profound immobility during IR, neurosurgical and electrophysiological evidence identifies the locus of the inhibitory neurons in the brain stem and/or spinal cord.

The evidence reviewed leads to a unified working hypothesis of IR mechaisms. IR is considered to be caused by a group of neurons in the brain stem which inhibit spinal motoneurons, either directly or indirectly, when those inhibitory neurons are activated by a specific pattern of tactile and proprioceptive input.

Modulation of the IR control system appears to come from the limbic system, which under fear‐producing conditions, potentiates the IR in part by release of epinephrine. Inhibition of the IR control system appears to come from the neocortex, as well as the brain stem reticulum, when it is activated by nonspecific, arousing somaesthetic sensations that produce generalized activation of the neocortex and skeletal muscle.
Effect of serum deprivation on myelinating mouse cerebellum cultures
Authors: Kim Seung U.
Published: January 2005

In order to investigate the effect of nutrient deprivation on brain development, mouse cerebellum cultures were grown in nutrient media with reduced serum concentration. After 9–18 days in vitro, experimental cultures grown in media with low serum concentration exhibited a delayed and retarded myelination. Electron microscopic examination of experimental cultures revealed profiles of deficient myelination, but showed normal neuronal and synaptic structures. The amount of myelin basic protein measured by radioimmunoassay was markedly reduced in experimental cultures. Activity of cholinesterase in these experimental cultures was also decreased.
Effects of neonatal hypothyroidism on cerebral and cerebellar synaptosome development
Authors: Verity M. Anthony , Brown W. J. , Cheung M. , Huntsman H. , Smith R.
Published: January 2005

The effect of hypothyroidism on cerebral and cerebellar synaptosome development has been studied. Neonatal hypothyroidism was induced following addition of 0.3% propylthiouracil to the diet of nursing mothers. Maturation profiles of total synaptosome fraction and specific activities of lactate dehydrogenase, Na+K ATPase, cytochrome c oxidase, and protein were obtained from days 6 to 32 on synaptosomes isolated from Ficoll‐sucrose gradients. The greatest changes were found in the total activities of enzymes isolated from the cerebellum. Hypothyroidism induced a retardation of LDH and cytochrome c oxidase in cerebellar synaptosomes, but no change in corresponding specific activities. Maximum rates of 14C‐leucine incorporation into cerebellar synaptosome protein was found at 16–20 days, after which a rapid decline occurred to adult levels at 32 days. In neonatal hypothyroidism, synthesis was significantly reduced at 8 and 14 days, but reached control levels or above at 21–32 days. In the cerebrum, maximum rates of 14C‐leucine incorporation into synaptosome protein were identified at 8–12 days in normal with a rapid drop to adult levels at approximately 20 days. In neonatal hypothyroidism, peak activities were identified at 14 days and increased activities over control were noted at 14, 20 and 30 days.

These observations demonstrate the sensitivity of the developing cerebellar synaptic apparatus to neonatal hypothyroidism, with a protraction in the peak levels of synaptosome protein synthesis in cerebrum and cerebellum.
RNA release from isolated brain cell nuclei: Influence of the postnatal cerebral development
Authors: De Guglielmone Alicia E. Ramirez , Duvilanski Beatriz H.
Published: January 2005

A method to measure the “in vitro” RNA release from rat brain cell nuclei was described. Nuclear RNA was prelabelled “in vivo” for 30 or 120 min. In the first case the released RNA was heterogeneous and its electrophoretic mobility was similar to that of cytoplasmic messenger RNAs; nuclei prelabelled for 120 min mostly released the two major species of ribosomal RNAs. The release of mRNA form the nuclei increased during cerebral development while that of the ribosomal RNAs did not. The increased capacity of the nuclei to release “rapidly labeled” RNA with age neither determined an increase of the polysomal population, nor seemed to be dependent on cytoplasmic macromolecules.
The effect of gallamine triethiodide on the activity of gamma motor neurons in the acute spinal cat
Authors: Sherry Clifford J.
Published: January 2005

Gallamine triethiodide, a drug commonly used in neurophysiological experiments, causes statistically significant and inconsistent changes in the information‐carrying capacity of trains of action potentials generated by members of a population of gamma motor neurons recorded from the same cat under the same conditions during the same time period.
Hepatic enzyme activities in weanling rats with ventromedial and dorsomedial hypothalamic lesions
Authors: Bernardis Lee L. , Rosen Fred , Goldman Jack K. , Martin Roy
Published: January 2005

Weanling rats received bilateral electrolytic lesions in the ventromedial (VMN) or dorsomedial (DMN) hypothalamic nuclei; sham‐operated rats served as controls. The animals were maintained under standard conditions for 13–;17 days post‐operatively and killed by decapitation. In addition, to measurements of weight gain and linear growth, Lee Index, and food intake, and activities of several hepatic enzymes and hepatic protein content were determined in untreated rats and in animals injected with 20 mg/kg cortisol 4 hours prior to sacrifice. In accordance with previously established data, weanling rats with VMN lesions did not gain more weight or eat more than their controls but became obese and retarded in linear growth. Weanling rats with DMN lesions showed both reduced ponderal and linear growth and were hypophagic but had normal body composition. Rats with VMN lesions had significantly increased activities of alanine transaminase (AT), serine dehydratase (SD), and hepatic protein; tryptophan oxygenase (TO) was decreased. In VMN‐lesioned rats treatment with cortisol decreased tyrosine aminotransferase (TKT) and liver protein. Lesions in the DMN increased AT and liver protein but left TKT unchanged. Cortisol induced TO and TKT in comparison with vehicle‐treated DMN rats. In another experiment, hepatic alanine tranaminase (AT) and fructose‐1,6,diphophatase (FDPase) were found to be elevated, but levels of pyruvate carboxylase (PC), phosphoenolpyruvate carboxykinase (PEPCK), and plasma glucagon were normal in rats with VMN lesions. The failure to find changes in 2 key gluconeogenic enzymes suggests that the enhanced gluconeogenesis in VMN rats demonstrated in a previous study depends more on substrate availability than on changes in enzyme activity. The data suggest that the central nervous system plays a role in the regulation of certain enzymes involved in protein metabolism.
Free amino acid pool in the brain of mice homozygous for the gene “dilute lethal”
Authors: Simler Dr Simone , Essayag S. , Ledig M. , Koehl C. , Mandel P.
Published: January 2005

The neurologic mutant “dilute lethal” (dl) mice, which reveal several neurologic and biochemical disturbances similar to human phenylketonuria, were used to investigate some aspects of amino acid disorder. We have studied the free amino pool in the brain of “dl” mice and of their control littermates as well as phenylalanine and tyrosine levels in brain and liver as a function of age and after phenylalamine overload. The tyrosine level decreased in brain and liver of affected mice whereas the phenylalanine/tyrosine ratio increased as a function of age. The significantly higher phenylalanine level and phenylalanine/tyrosine ratio in the liver of 20‐day‐old “dl” mice suggest a lower liver phenylalanine hydroxylase activity. After phenylalanine overload, the impairment of phenylalanine metabolism is predominant in the brain of “dl” mice, suggesting a disturbance in phenylalanine hydroxylation. A decrease in the level of several amino acids occurs in the brains of “dl” mice without or after phenylalanine overload; these facts might correspond to a disturbance in the transfer of amino acids to the brain and may lead to impairment in protein synthesis.
Effects of strychnine, bicuculline, and picrotoxin on inhibition of hypoglossal motoneurons
Authors: Felpel Leslie P.
Published: January 2005

Postsynaptic potentials, evoked by lingual or hypoglossal nerve stimulation, were recorded from hypoglossal motoneurons of the cat with glass microelectrodes. Lingual nerve‐evoked inhibitory postsynaptic potentials (LIPSPs) were recorded in 98% of hypoglossal motoneurons. Hypoglossal nerve stimulation caused a hyperpolarzing potential following the antidromic spike in all hypoglossal motoneurons tested. This potential was unaffected by depolarizing or hyperpolarizing currents, could not be evoked at a stimulus strength less than that which was threshold for the antidromic action potential, and did not change in shape or amplitude at stimulus strengths which were above threshold for antidromic invasion. This hyperpolarpolarizing potential was therefore considered to be an afterhyperpolarization. However, hypoglossal nerve‐induced inhibitory postsynaptic potentials were recorded from hypoglossal units which had characteristics of interneurons, thus suggesting the presence of afferent fibers in the hypoglossal nerve.

The hypoglossal nerve‐induced afterhyperpolarization was not affected by strychnine, bicuculline, or picrotoxin. The LIPSP was antagonized by strychnine but unaffected by bicuculline or picrotoxin. The results suggest that inhibition of hypoglossal motoneurons via the lingual nerve is more likely to be mediated by glycine than gamma‐aminobutyric acid (GABA) and is therefore similar to the strychnine‐sensitive postsynaptic inhibition of spinal motoneurons.
Acetylcholinesterase activity in ventricular and cisternal csf of dogs: Effect of chlorpromazine
Authors: Bareggi Silvio R. , Giacobini Ezio
Published: January 2005

Acetylcholinesterase (AChE) activity in dog plasma is significantly higher than in either ventricular or cisternal CSF. However, since protein levels in plasma are about 100‐fold higher than in CSF, the specific activity of AChE is lower in plasma than in CSF. Acetylcholinesterase activity in plasma represents only 22% of total cholinesterase (ChE) activity, while preliminary findings indicate that in ventricular CSF it is 50–60%. Acetylcholinesterase activity in ventricular CSF is significantly lower than in cisternal CSF. Chlorpromazine (10 mg/kg, intravenous), a drug which increases acetylcholine turnover, increased AChE‐specific activity in all dogs. Our results support the hypothesis of a neuronal origin of AChE activity in CSF.
Coding of increments and decrements in stimulus intensity in single units in the cochlear nucleus of the rat
Authors: Møller Aage R.
Published: January 2005

The response of single units in the cochlear nucleus when confronted with step increments and step decrements in stimulus intensity was studied in the rat using tones that were amplitude modulated with square waves or with pseudorandom noise. Cycle histograms of the responses to tones modulated with square waves revealed that the probability of firing increased as a result of step increments in stimulus intensity for tones at characteristic frequency (CF) and that the probability of firing decreased as a result of step decrements. When two tones were presented simultaneously, one at CF and one at the unit's best inhibitory frequency (BIF), and one or the other of the tones was modulated, the modulation of the cycle histogram of the responses was greater than when only one tone was presented. Modulation of the inhibitory tone gave rise to histograms that were mirror images of the histograms of the responses to modulation of the excitatory tone. An increase in probability of firing always occurred at a faster rate than a decrease, independent of whether the increase was brought about by increase in the intensity of the excitatory tone or by a decrease in the intensity of the inhibitory tone.

The cycle histograms of the responses to square wave‐modulated tones and the step response estimated from the responses to tones amplitude‐modulated with pseudorandom noise showed a greater similarity when the cycle histograms depicted the case of an increase in the probability of firing than when they concerned a decrease in the probability of firing.
The chemoarchitectonics of the diencephalon of frog (rana tigrina)
Authors: Sood P. P.
Published: January 2005

The study deals with the distribution of acid and alkaline phosphates, ATPase, 5‐nucleotidase, nonspecific esterase, specific cholinesterase, and β‐galactosidase in the diencephalon on the frog.

The highlights of the present study are the following: (i) Acid phosphatase is present in all the neurons, whereas the tracts and commissures are completely negative. (ii) Most of the tracts and commissures are positive for 5‐nucleotidase. This confirms the author's previous findings that the tracts and commissures of all the areas of frog brain are intensely positive for 5‐nucleotidase. (iii) β‐galactosidase activity in the nuclei of the diencephalon is either mild or completely absent, whereas the commissures and tracts show positive activity. (iv) Habenulothalamic connections are intensely positive for specific cholinesterase and non‐specific esterase, moderately positive for β‐galactosidase and completely negative for other enzymes. (v) The epiphysis (pineal organ) shows intense reaction for adenosine triphosphatase, acid phosphatase, and 5‐nucleotidase and moderate reaction for alkaline phosphatase and non‐specific esterase. In contrast to the above enzymes, the specific cholinesterase and β‐galactosidase are completely missing. (vi) Lateral forebrain bundles are completely negative for all the enzymes except alkaline phosphatase and β‐galactosidase.

The distribution of these enzymes has been correlated with the functional aspects of various nuclei, tracts, and commissures of the diencephalon of the frog.
Intracellular studies of GABA and taurine action on the neurons of the cat sensorimotor cortex
Authors: Alexandrov A. A. , Batuev A. S.
Published: January 2005

The action of taurine and GABA on the cat cerebral cortex neurons was studied. Electrophoretically administered taurine and GABA hyperpolarized the neuron membrane. GABA, in contrast to taurine, sharply increased the somatic membrane conductance. Taurine action was weaker than that of GABA and its effects were not always observed. However, in a number of instances it exerted inhibitory influence similar to GABA action. Some facts make it possible to suppose that taurine acts mainly on the neuron dendrites. The data obtained are in accordance with the supposition that taurine might be an inhibitory transmitter in the cerebral cortex.
Cystathionine synthase in rat brain: Regional and time‐of‐day differences and their metabolic implications
Authors: Lee Kohl Randall , Quay W. B.
Published: January 2005

In relation to concern for probable interrelations of cystathionine synthase (CS, EC 4.2.1.21) and methionine, one‐carbon, and 5‐hydroxytryptamine metabolism, we have investigated tissue and time‐of‐day differences in CS activity in the laboratory rat under standardized conditions. Liver, kidney, and pancreas had highest CS activities; nine regions of the CNS had mean activities ranging from 4.5% (lumbosacral cord) to 24.5% (hypothalamus) of mean hepatic activity; pituitary and adrenal glands lacked detectable CS activity. Although significantly lower CS activity occurred in liver (↓ 9%, P < 0.050) and kidney (↓ 13%, P < 0.025) during the interval two hours before to two hours after the daily onset of darkness, no significant changes were found in hypothalamus, cerebellum, or medulla oblongata. Regional CNS differences in CS activity appeared to be without correlation in relation to published data on relative contents of 5‐hydroxytryptamine, tryptophan 5‐hydroxylase (EC 1.14.16.4), 5,10‐methylene reductase N5‐methyltetrahydrofolate‐NAD‐oxidoreductase, (EC 1.1.1.78), or 5‐methyltetrahydrofolate. Therefore, among CNS regions examined, a critical deficiency in ability to metabolize a homocysteine load is considered to be unlikely under normal conditions.
Dissociated effects of inhibition of catecholamine synthesis on motor activity, “emotionality,” and aggression in mice
Authors: Matte A. C. , Tornow H.
Published: January 2005

The inhibitor of catecholamine synthesis at the tyrosine hydroxylase level, alpha‐methyltyrosine, administered in daily doses of 250 mg/kg IP, altered motor activity and aggressive behavior of isolated male mice in ten‐minute paired encounter tests conducted on nine successive days. Motor activity was determined by an electromagnetic activity meter which measures fine and coarse movements separately. Coarse motor activity correlated significantly with aggressive behavior. Nonagressive fine motor activity was significantly increased, while all the parameters of aggressive behavior showed a significant decrease in aggression. Increased escape behavior, heterogrooming, squeaking, and two cases of stupor were observed, suggesting possible equivalents of anxiousness. The defecation rate did not differ from that of the control group, victors having had a higher rate than losers.

Results are discussed in connection with the “construct of emotionality” and the hypothesis of there being several categories of aggression with corresponding biochemical correlations.
High‐energy phosphate compounds and some glycolytic substrates in the rat brain during hypoxia
Authors: Broniszewska‐Ardelt Barbara , Sikorska Marianna
Published: January 2005

The influence of acute and prolonged (with resuscitation) hypoxia, upon some glycolytic substrates and high energy phosphate compounds in the rat brain, was studied. Acute hypoxia decreased the content of glucose and glucose‐6‐phosphate as well as of high energy phosphate compounds. Simultaneously, an increase of lactic acid level was recorded.

Some adaptation features could be observed, when 30‐minute hypoxia with resuscitation was studied. Brain content of high energy compounds returned to the normal value, while that of glucose increased twice over control. However, the level of lactic acid was still increased.
Hypothalamic cathepsin D: Assay and isoenzyme composition
Authors: Akopyan T. N. , Barchudaryan N. A. , Karabashyan L. V. , Arutunyan A. A. , Lajtha A. , Galoyan A. A.
Published: January 2005

A sensitive and convenient method of endopeptidase assay using as substrate globin modified with pyridoxal‐5‐phosphate was used for determination of acid proteinases in bovine hypothalamus separated by isoelectric focusing. The soluble protein fraction of hypothalamus upon elution from Sephadex gave five peaks of proteinase activity at pH 3.2. The properties indicate that these peaks of endopeptidase activity are isoenzyme forms of cathepsin D.
Metabolic inhibitors and subcellular distribution of GABA
Authors: Sarhan Shakir , Seiler Nikolaus
Published: January 2005

Experimental procedures are described which are believed to yield results that reflect, within certain limits, the in vivo changes of the size of the GABA pool in nerve endings in comparison with those of all other GABA pools. Two irreversible GABA‐T inhibitors, vinyl GABA and acetylenic GABA, two GAD inhibitors, 3‐mercaptopropionic acid and pyridoxal phosphate glutamyl‐γ‐hydrazone, and di‐n propylacetate, a clinically useful anticonvulsant, have been studied to determine their effects on GABA compartmentalization in mouse brain cortex.

The changes elicited by these drugs in subcellular fractions of brain cortex homogenates support the notion that measurement of amino acid concentrations in crude synaptosomal fractions and in supernatant fractions under controlled conditions allow one to draw conclusions about relative changes of pool sizes in vivo. In particular this work showed that a specific increase in the concentration of GABA within the nerve endings is more important than a large increase of total brain GABA as a means of decreasing susceptibility to a variety of chemically or physically induced seizures.
On some derivatives of ferrocene, novel acetylcholinesterase inhibitors
Authors: Hetnarski Bogumil , Lajtha Abel , Wisniewski Henryk M.
Published: January 2005

Eight novel methylcarbamates, derivatives of ferrocenylketoximes and aldoximes, and ferrocenyl‐p‐hydroxyphenylaldimine were prepared. They are the first carbamates in the field of ferrocene derivaties. Their anticholinesterase activity was tested and found to fall in the range of 10−4 through 10−6 M (I50). The correlation between the activity of the compounds and the kind of substitutents grafted on the methylene carbon atom is discussed.
The role of the medial septal nucleus in mediating adrenocortical responses to somatosensory stimulation
Authors: Feldman Shaul , Conforti Nissim
Published: January 2005

In view of the demonstrated involvement of the hippocampus in the mediation of adrenocortical responses following sciatic nerve stimulation, the role of the septum and the preoptic area in the transmission of this response was investigated. Changes in plasma corticosterone following ether stress and photic, acoustic, or sciatic nerve stimulation were studied in intact rats and in animals with lesions in the medial septal nucleus and the preoptic area. The response to ether stress and to photic and acoustic stimulation was normal in these animals. However, the adrenocortical response to sciatic nerve stimulation was partially reduced in the rats with lesions in the superior, but not in the inferior preoptic area, and it was completely blocked in those with medial septal lesions. Our previous and present experiments indicate that the ventral hippocampus, the fimbria, the septum, and anterior hypothalamic afferents mediate the adrenocortical response to somatosensory stimulation.
Choline acetyltransferase: Purification and characterization
Authors: Chao Li‐Pen
Published: January 2005

Choline acetyltransferase catalyzes the synthesis of the neurotransmitter acetylcholine and is the specific enzyme marker for cholinergic neurons. This review summarizes and discusses different purification procedures, as well as the characteristics of this important enzyme. Explanations for conflicting or controversial results concerning this enzyme are also discussed.
Increased activity of a phospholipid base‐exchange system by the differentiation of neoplastic cells from the nervous system
Authors: Erkell L. J. , de Medio G. E. , Haglid K. , Porcellati G.
Published: January 2005

The activity of a base‐exchange enzyme system, specific for the polar headgroups of brain phospholipids, was measured in both C 1300 mouse neuroblastoma (clone 41 A3) and human glioma 138 MG cell lines. This base‐exchange is thought to occur between free nitrogenous bases and membrane‐bound phospholipids. The incorporation of free 14C‐labeled ethanolamine and L‐serine was determined in undifferentiated and morphologically differentiated cells. Both cell lines showed a significant increase in ethanolamine and L‐serine incorporation upon differentiation.
Dextro‐phenylalanine inhibits potassium‐evoked 3H‐noradrenaline release from hypothalamus but not of 3H‐dopamine from rat caudate nucleus
Authors: Julio Pardal Fernández
Published: January 2005

Action of dextro‐phenylalanine (d‐Phe) on catecholamine release elicited by K+ 20 mM has been studied in isolated slices of rat central nervous system (CNS). d‐Phe (3 × 10−3 M) produced inhibition of the fractional release of 3H‐noradrenaline but not of 3H‐dopamine. The mentioned effect is Ca2+ dependent and was antagonized when this ion was incremented to 2.6 mM in the medium or in the presence of ionophore A‐23187 (4 × 10−5 M). Neither acetylsalicylic acid nor indomethacin (prostaglandin biosynthesis inhibitors) interferes with the effect of d‐Phe, showing that by itself it would not reach through the prostaglandin pathway. d‐Phe modified neither the noradrenaline neuronal uptake nor its metabolism at the CNS. The findings suggest that d‐Phe acts through a Ca2+‐dependent mechanism, possibly by specific receptors and in parallel with feedback circuits that involve alpha‐adrenoceptors, muscarinic receptors, or prostaglandins.
Starvation‐induced changes in transport of ketone bodies across the blood‐brain barrier
Authors: Pollay Michael , Alan Stevens F.
Published: January 2005

The permeability of the blood brain barrier (BBB) to β‐hydroxybutyrate (β‐HB) was computed in fed and starved (five days) rats by the simultaneous measurement of cerebral blood flow (diffusible indicator method‐123I‐iodoantipyrine) and brain uptake of 14C‐β‐HB (relative to a 3H2O reference). The results from the present study demonstrate that the movement of β‐HB across the BBB in rat is by a carrier‐mediated process. During starvation, total movement (carrier‐mediated and diffusionary) of this ketone body into brain was observed to be enhanced because of an increase in the diffusionary loss across the cerebral capillary. The calculated transport kinetics also suggest that the β‐HB molecule has a greater affinity for the transport (mediator) protein during starvation, although the maximal rate of uptake by brain due to a carrier processes mediated Vmax is decreased either because there is a smaller quantity of the mediating molecule or because there is trans inhibition by a high cellular concentration of β‐HB or some analog.
Effects of 2‐deoxy‐D‐glucose on multi‐unit activity of the hypothalamus in rats
Authors: Rabin Bernard M. , Miller Donald S.
Published: January 2005

Mutli‐unit activity was recorded from the diencephalon of unanesthetized, immobilized female rats. Less than 50% of the recording sites in the hypothalamus showed changes in the level of multi‐unit activity to changes in the level of glucose utilization induced by injection of 2‐deoxy‐D‐glucose (2‐DG). It was also not possible to specificy an area within the hypothalamus in which there was a concentration of recording sites which consistently responded to 2‐DG. Relatively large amplitude, long duration changes in multi‐unit activity levels were also observed in the optic tract, suggesting that 2‐DG induced a widespread cellular metabolic response to glucoprivation which may not have been related to the regulation of feeding.
DNA DNases in normal and undernourished rat brain
Authors: Rao K. Subba , Shrivastaw K. P. , Tiwari B. K.
Published: January 2005

Earlier studies from our laboratory [Shrivastaw and Subba Rao, 1975; Subba Rao and Shrivastaw, 1976] have indicated a positive correlation between cell proliferation, as indicated by DNA synthesis, and the levels of DNases in developing chick brain. Since undernutrition is known to affect cell prolifereration in developing brain, those studies are now extended to see the effect of early undernutrition on the levels of DNA and DNases along with RNA and protein in developing rat brain. Early nutritional deprivation resulted in lesser amounts of DNA, but the concentration of DNA per gram of brain did not alter. DNA, RNA, and protein values in brains of those rats undernourished from birth to 14 days but subsequently rehabilitated up to 130 days, exhibuited complete recovery, while rehabilitation up to 50 days did not show full recovery in the case of DNA. Both the specific activity and total activity of acid and alkaline DNases showed significant reduction in 14‐day‐old undernourished brain. However, with continued nutritional restriction up to 24 days, the specific activity of these enzymes returned to normal, although the total activity was still in deficit. These results, coupled with those on DNA levels, indicate that a compensatory mechanism may come into play when developing brain is exposed to caloric restriction.
Regional changes in phenylethanolamine‐N‐Methyltransferase of rat brain during development
Authors: Díaz Borges J. M. , Rodríguez L. , Urbina M.
Published: January 2005

The changes of phenylethanolamine‐N‐methyltransferase (PNMT, EC 2.1.1.28), the enzyme that catalyzes the final step in the biosynthesis of adrenaline, were studied during the development of several regions of rat brain. PNMT is present in medulla oblongata‐pons, hypothalamus, cerebellum, and midbrain five days before birth, and a progressive increase in the enzyme activity is observed during development. The adult levels are attained between 15 and 20 days, depending on the region. The increases in PNMT activity in the rostral regions are higher than in the caudal regions. PNMT attains adult levels earlier than tyrosine hydroxylase and dopamine‐β‐hydroxylase. The apparatus for adrenaline synthesis seems to be mature at three weeks after birth in the medulla oblongata‐pons, which contains the cell bodies of adrenaline‐containing neurons. In the other regions the adult levels of enzyme activity are attained at 15 days after birth.
Adrenal and hypothalamic dopamine‐beta‐hydroxylase activity in the hamster: Evidence for species‐distinctive day‐night and post‐pinealectomy differences in activity
Authors: Banerji Tapan K. , Kachi T. , Quay W. B.
Published: January 2005

Dopamine‐beta‐hydroxylase (DBH) activities were measured in the adrenal gland and hypothalamus of the golden hamster (Mesocricetus auratus) by means of a sensitive radioenzymatic method. Groups of unoperated control (C), sham pinealectomized (SPX), and pinealectomized (PX) adult males were sacrificed shortly before (09:00 h) and after (11:00 h) the onset of darkness of the daily photoperiod of LD 12:12 (lights on 22:00 h to 10:00 h). In neither adrenal gland nor the hypothalamus were there any day‐night changes in the C groups. Pinealectomy led to no significant differences in hypothalamic DBH activity either in light or in dark. However, intracranial surgery resulted in increased DBH activity in the adrenal gland, evident in both light and dark. Although this increase was greatest in the PX groups, intracranial surgery in SPX groups also showed a trend of increase in adrenal DBH, evident even one month after surgery. Such an increase, however, was not found in hypothalamic DBH in the same SPX groups. In both the adrenal gland and the hypothalamus, copper‐sensitive endogenous inhibitors of DBH did not show any notable change in concentration, either in relation to the daily light‐to‐dark change or as a consequence of intracranial surgery. These and related results suggest that important interspecies variations exist in DBH activities in relation to diurnal changes, and also in control or modulation by pineal and other factors.
Effects of morphine on sensory‐evoked responses recorded from central gray, reticular formation, thalamus, hypothalamus, limbic system, basal ganglia, dorsal raphe, locus ceruleus, and pineal body
Authors: Dafny N. , Marchand J. , McClung R. , Salamy J. , Sands S. , Wachtendorf H. , Burks T. F.
Published: January 2005

Field potential recordings of acoustic and photic‐evoked responses were obtained from 15 brain sites of freely behaving unanesthetized rats previously implanted stereotaxically with permanent electrodes. Several dosages of morphine (1, 5, 10, 30, and 50 mg/kg) were examined. The activities recorded from all the structures in this study, except the cochlear nucleus (CoN), were affected by morphine. Different sensitivities to morphine threshold were observed between structures, and several structures exhibited dose‐related patterns (ventromedial hypothalamus (VMH), caudate nucleus (CN), central gray (CG), hippocampus (Hipp), and lateral septum (Spt)). Several brain sites, after the initial dose of morphine, did not recruit more responses to subsequent doses of the drug, ie, exhibited all‐or‐none responses (pineal body (PB), medial thalamus (MTh), anterior hypothalamus (AH), mesencephalic reticular formation (MRF), and the dorsal raphe (DR)). In some structures, morphine induced increases in the response amplitudes, while in other sites decreases in response amplitudes were elicited. Biphasic responses, ie, increases in response amplitude after low doses of the drug and decreases in response amplitude after higher dosages, were also observed (VMH, CN, DR, CG, and MRF). The acoustic‐evoked responses were affected by morphine more than the photic responses. The present observations indicated that (1) morphine exerts effects in many parts of the central nervous system (CNS); (2) some structures are more sensitive to morphine than others; (3) only a few structures exhibit dose‐related patterns and, thus, may represent sites of direct morphine action; (4) some structures exhibit all‐or‐none responses; and (5) morphine depressed activity in some structures and increased activity in others, ie, morphine elicited different effects in different structures.
Tay‐sachs disease brain cells in culture: Mobilization of stored GM2 after concanavalin A‐mediated uptake of hexosaminidase A
Authors: Hoffman Linda M. , Brooks Steven E. , Amsterdam Daniel , Oropello John , Schneck Larry
Published: January 2005

A human Tay‐Sachs disease (TSD) fetal‐brain‐cell line is a useful model for the disease since the cells lack hexosaminidase A and accumulate the ganglioside, GM2. This brain‐cell line was used to assess the effect of hexosaminidase A treatment on GM2 storage material. Entry of placental hexosaminidase A into the cells was obtained by pretreatment of the cultures with concanavalin A. Cells were analyzed periodically during six days. During the course of the experiment, GM2 in the cells decreased by approximately 50%. A substantial amount of hexosaminidase A was maintained in the cultures throughout the experiment. This strategy was successful in mobilizing stored GM2 in TSD brain‐cell cultures. Therefore, the activating factor needed for hexosaminidase A activity must be present in TSD‐cultured brain cells.
Reactions of lateral geniculate cells to chemical and electrical excitation of the visual cortex in rabbits
Authors: Molotchnikoff S. , Richard D.
Published: January 2005

In anesthetized and paralyzed rabbits unitary discharges of lateral geniculate nucleus (LGN) were studied after cortical excitation by strychnine and following electrical stimulation of the visual cortex (VC). Results showed that local application of strychnine produced a general increase of the spontaneous and evoked activity of geniculate cells. By contrast, cortical depression with KCl led to a differential decrement of one of the evoked responses (on or off). Electrical cortical stimulation paired with on or off stimuli led to a differential increment of on or off responses. The results support the notion that, in rabbits, the corticogeniculate system is center‐surround organized. A diagrammatic model is proposed to account for the relationship between the VC and the LGN in rabbits.
Studies on choline and ethanolamine phosphoglyceride biosynthesis in developing rabbit brain
Authors: Fimbres E. , Saenz R. , Smith N. , Percy A. K.
Published: January 2005

Activities of cholinephosphotransferase (EC 2.7.8.2) and ethanolaminephosphotransferase (EC 2.7.8.1) were evaluated in microsomal preparations derived from rabbit cerebrum. Animals ranged in age from nineteen day's gestation through two months of postnatal development. Under optimal conditions the properties of these transferases in rabbit brain were remarkably similar relative to pH, divalent cation requirements, and apparent‐Km values for the CDP‐intermediates and the lipid acceptor, respectively. Cholinephosphotransferase‐specific activity exhibited a dramatic rise during the last 15%–20% of fetal life and a second rise to a maximum near the 15th postnatal day. Ethanolaminephosphotransferase‐specific activity exhibited a similar, but less striking age‐related increase during the same period. Growth of rabbit cerebrum, as determined by weight, increased 30‐fold during this same period (24 days gestation to the 19th postnatal day). Specific activities of these transferases were similar in brain preparations from mid‐fetal and early adult rabbits. The maximum specific activity of cholinephosphotransferase exceeded that of ethanolaminephosphotransferase by 3–4‐fold.

Age‐related changes in the specific activities of these transferases appear to correlate with the developmental pattern of morphological and compositional events occurring in rabbit cerebrum during the last third of gestation and the first three weeks of postnatal life.
Regional changes in adrenaline of rat brain during development
Authors: Borges J. M. Díaz , Chávez M.
Published: January 2005

The changes of adrenaline during development were studied in several regions of rat brain. Adrenaline is present in hypothalamus, medulla oblongata‐pons, midbrain, and cerebellum. Adult levels are attained between 15 and 30 days, depending on the region. These adult levels are attained earlier in the caudal regions than in the rostral regions. In cerebellum and medulla oblongata‐pons, the adrenaline content reaches a maximum at 15 days which is close to the time in which the levels of phenylethanolamine‐N‐methyltransferase (PNMT) reach their maximum. In midbrain and hypothalamus, there is a lag between the adult levels of adrenaline and the activity of PNMT. Adrenaline reaches adult levels at 25 days in midbrain and at 30 days in hypothalamus, while PNMT activity adult levels are attained at 15 days.
High‐affinity uptake system for cysteine in crude synaptosomal fractions of rat cerebral cortex
Authors: Misra Chandra H.
Published: January 2005

The in vitro uptake of [35S] cysteine was studied in crude synaptosomal preparation of the cerebral cortex of rat. The accumulation of cysteine was found to be temperature‐ and time‐dependent. It was linear at least for four minutes at 37 C with characteristics of saturable kinetics. Uptake of cysteine was Na+‐ and K+‐dependent. Increasing the Na+ ion concentration increased the accumulation of cysteine in synaptosomal preparations; unlike the Na+ ion, an increase in the K+ ion, an increase in the K+ ion inhibited cysteine uptake. Cysteine was accumulated against concentration gradients by a saturable mechanism. Double reciprocal plot of the cysteine uptake suggests two types of affinity systems, with Km values for the high‐affinity uptake of about 12.2 μM and for the low‐affinity uptake of about 4 mM. The high‐affinity uptake was also significantly inhibited by ouabain, a potent inhibitor of the Na+‐K+‐dependent ATPase, and other metabolic inhibitors. The results of the effects of cysteine analogues on uptake also suggested that it is a substrate‐specific high‐affinity uptake system for cysteine.