bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of morphine and some other narcotic analgesics on brain tryptophan concentrations
Authors: Crossley A. W. A. , Slater P. 
Published: January 2005

AbstractAn acute dose of morphine increased brain tryptophan in mice. This effect was not prevented by naloxone nor was it produced by other narcotic analgesics. Dextrorphan, but not levorphanol, had a similar effect to morphine. A large dose of tryptophan had no effect on the antinociceptive action of morphine in mice. Morphine increased brain tryptophan in rats. This effect was prevented by naloxone. A large dose of tryptophan antagonised the antinociceptive action of morphine in the rat.
Induction of two distinct behavioural responses by chronic treatment with apomorphine
Authors: Kenny Marie , Lynch Marina , Leonard B. E. 
Published: January 2005

AbstractMale Wistar rats treated with apomorphine (1.0 mg/kg) twice daily for several days exhibited two distinct behavioural responses characterized by stereotyped sniffing or ritualized fighting. The fighting response first appeared on the third day of drug administration and became more severe with repeated treatment. It differed from previously reported apomorphine‐induced aggression [McKenzie, 1971] in that dominant and subordinate rats did not emerge between pairs of fighting rats. Mild defensive fighting occurred in other animals after seven days of drug treatment. Marked differences were observed between aggressive and nonaggressive rats both during the acute effects of the drug and several hours after these effects had worn off. These differences included disturbance in the “open field” behaviour and the reaction to handling. Once a specific behaviour was established in an individual rat, it was not possible to induce a different reaction to apomorphine.It was shown that, in a group of rats similar in age, sex, strain, and body weight, chronic treatment with a low dose of apomorphine induced distinct and reproducible behavioural patterns. The standard rating scale for apomorphine‐induced stereotyped behaviour was shown to be inadequate for the study of such diverse behaviours.
Tail‐pinch‐induced hyperphagia in weanling rats with dorsomedial hypothalamic lesions
Authors: Bernardis Lee L. , Bellinger Larry L. , Goldman Jack K. 
Published: January 2005

AbstractDorsomedial hypothalamic lesions (DMNL) were produced in 26‐day‐old and 44‐day‐old male rats. Sham‐operated rats served as controls. Tail‐pinching (TP) was performed for five minutes at a time over two periods: the first TP period of six sessions each from post‐operative day 1 to day 17 and the second TP period of eight sessions from post‐operative day 18 to day 35. Three equicloric diets, high‐carbohydrate, high‐fat, and high‐protein, were presented ad libitum in pellet form during the TP sessions. Lab chow was available ad libitum in the home cages. Rats with DMNL at age 26 days did not show TP‐induced hyperphagia and HCD preference compared to the controls until the second TP period. In rats lesioned at age 44 days, TP‐induced hyperphagia and HCD‐preference (compared with controls) became evident immediately after the operation. In the home cages (lab chow), DMNL rats showed a decline in food intake from the first to the second TP period, while the sham‐operated controls showed an increase. TP‐induced hyperphagia in the rat with DMNL does not appear to be caused by some arousal‐related process as has been shown for the rat with lateral hypothalamic lesions. Lesions in the nigrostriatal system have been reported to attenuate TP‐induced feeding, while the present study indicates that lesions in the DMN enhance it. This suggests that fibers in the central nervous system may be involved in facilitation or inhibition of TP‐induced eating.
Characterization of unit activity recorded from septum, thalamus, and caudate following incremental opiate treatment
Authors: Dafny Nachum , Rigor Benjamin M. 
Published: January 2005

AbstractThe effects of a wide range of morphine doses and of its antagonist, naloxone, on spontaneous multiunit discharges in freely moving rats were recorded simultaneously from the septum (Spt), medial thalamus (CM‐PF complex), and caudate nucleus (CN). A high percentage of neurons in these three areas are affected by morphine.Neurons in the CM‐PF complex exhibited a greater number of morphine‐induced changes (104/145) than did those in the caudate nucleus (79/160), or in the septum (67/150).The morphine‐induced changes exhibited dose‐related patterns: the three structures examined in the present study exhibited four response patterns to incremental doses of morphine: either a monophasic effect, an increase or decrease in firing rate, or a biphasic effect; ie, lower morphine doses induced a decrease in activity, whereas higher doses induced an increase in firing rate.There was no observed correlation between the response patterns in the three regions. The technique provides a tool with which to identify and classify the specific response patterns induced by morphine in specific brain regions, and the results may indicate that each region plays a different physiological role in the effects induced by morphine.
Chemical requirements of vasopressins for barrel rotation convulsions and reversal by oxytocin
Authors: Abood L. G. , Knapp R. , Mitchell T. , Booth H. , Schwab L. 
Published: January 2005

AbstractWhen vasopressin is administred into the lateral ventricles of rats it produces severe convulsive activity characterized by a rapid barrel rotation. Electrical recordings from the dorsal hippocampus indicate marked elevations in the amplitude and frequency at doses of 5 μl of 2 × 10−5 M vasopressin. No significant behavioral effects were noted with oxytocin, somatostatin, β‐melanophore‐stimulating hormone, adrenocorticotropin, or leu‐enkephalin. Pretreatment of the rats with intraventricularly administered oxytocin, β‐MSH, or systemically administered Dilantin prevented the vasopressin‐induced seizures. With the use of chemical and enzymic modification procedures, the essential fragment and amino acids of vasopressin needed for the activity were determined. It was concluded that although the peptide could be acting by vasoconstricting blood arterioles and capillaries in the brain, it may also be exerting a direct excitatory action on neurons.
Neurophysiological evidence for tolerance and dependence on opiates: Simultaneous multiunit recordings from septum, thalamus, and caudate nucleus
Authors: Dafny Nachum 
Published: January 2005

AbstractMultiunit activity was recorded simultaneously from the septum (Spt), medial thalamus (PF‐CM complex), and caudate nucleus (CN) in freely behaving rats previously implanted with permanent nichrome semimicroelectrodes (62μ in diameter). A challenge dose of morphine (10 mg/kg) and its antagonist (naloxone 1.0 mg/kg) was examined in the same animals while they were morphine naive and after they had become morphine physically dependent. Electrophysiological observations indicated that it would be possible to identify three physiological phenomena: (1) activity related to morphine dependency; (2) activity related to tolerance; and (3) activity related to withdrawal. Experimental observations yielded three different electrophysiological patterns of activity related to tolerance. Each of the three central sites (Spt, PF‐CM, and CN) exhibited a different response pattern to morphine in morphine physically dependent animals.
Accumulation of GFA, the monomeric precursor of the gliofilaments, during development in normal mice and dysmyelinating mutants
Authors: Jacque C. , Lachapelle F. , Collier P. , Raoul M. , Baumann N. 
Published: January 2005

AbstractAstrocytic reactivity during the myelination period in the mouse was studied with immunochemical method, ie, quantitative determination of the soluble pool of the GFA protein. There is normally a maximum content at the time of early myelinogenesis in any structure; then the GFA level decreases and finally keeps constant for a long period during the adult life. This evolutive pattern is also observed in the dysmyelinating mutant quaking, with a permanent shift toward higher values especially in areas of earlier maturation. In the jimpy mutant, practically devoid of myelin, the increase of GFA occurs but does not stop until death, at 25 days postnatal. This study points out (1) the capacity of astrocytes to synthesize surprisingly high amounts of soluble GFA at periods of intense metabolic activity, and (2) the reactivity of astrocytes in relation to the degree of deficiency of the myelinating oligodendrocytes.
Immunohistochemical localization of the myelin basic protein and of the glial fibrillary acidic protein: Comparative study in normal, quaking and jimpy mice
Authors: Dupouey P. , Lucas C. V. , Gomes D. , Jacque C. 
Published: January 2005

AbstractThe topographical distribution of myelin basic protein (MBP) and of glial fibrillary acidic protein (GFA) have been compared in the CNS of 18‐day‐old normal, quaking, and jimpy mice using indirect immunofluorescence. Comparison was made in brain and spinal cord sections. MBP was strongly decreased in quaking and jimpy mice in all parts of the CNS. A pronounced gliosis was observed in jimpy mice with occurrence of numerous hypertrophied astrocytes. To a lesser extent, an astrocytic reaction was also observed in quaking CNS.
Intraventricular ACTH and vasopressin cause regionally specific changes in cerebral deoxyglucose uptake
Authors: Dunn Adrian J. , Steelman Suzanne , Delanoy Richard 
Published: January 2005

AbstractThe cerebral uptake of subcutaneously injected [3H] 2‐deoxyglucose (2DG) was used to determine regional changes of cerebral glucose uptake associated with peptide‐induced behaviors in mice. Evidence is presented that the use of [3H] 2DG (s.c.) gives results qualitatively similar to those obtained using intravenous [14C] 2DG. Lysine vasopressin, 1 μg intracerebroventricularly (i.c.v.), induced the characteristic hyperactivity previously described, and significantly decreased [3H] 2DG uptake in frontal cortex. ACTH1−24 (1 μg, i.c.v.) induced excessive grooming and concomitant decreases in [3H] 2DG uptake in olfactory bulb, pyriform cortex, and amygdala, and an increase in cerebellum. These results are only partly consistent with previous results on the cerebral sites of action of ACTH and vasopressin. These patterns of 2DG uptake are distinct from those observed following footshock, indicating that the peptide hormones mediate the effects of footshock on [3H] 2DG uptake only partially if at all.
Poly(A)‐ and nonpoly(A)‐RNA associated with rat brain microsomal fractions: In vivo labelling studies
Authors: Czosnek Henryk , Soifer David , Gal Alma , Mack Kathryn , Hochberg Abraham , Wisniewski Henryk M. 
Published: January 2005

AbstractThe time course of incorporation of radiolabelled precursor into RNA associated with rat brain free polyribosomes, rough membranes, and smooth membranes was measured following a single intracranial injection of [3H] orotic acid. Polyadenylated RNAs were separated from nonpolyadenylated RNAs by affinity chromatography on oligo (dT)‐cellulose columns. Poly(A)‐RNA associated with each of the microsomal fractions became more rapidly labelled than did the nonpoly(A)‐RNA of the same fractions. While the labelling profiles of the nonpoly(A)‐RNA isolated from the polyribosomes and rough membranes are similar from one fraction to another, the specific radioactivity of the poly(A)‐RNA isolated from free polyribosomes increased much more drastically than that of the poly(A)‐RNA associated with rough membranes. The labelling profiles of RNA species isolated from smooth membranes were very different in this respect from the two ribosomal fractions. There was a lag of more than four hours before significant label appeared in the RNA associated with the smooth membrane fraction. These studies demonstrate that the different populations of brain microsomal RNA are labelled at different rates, perhaps reflecting differences in the turnover of these RNAs and differences in their function.
Ionic mechanism of inhibition of long duration in aplysia synapse
Authors: Sawada M. , Enomoto K. , Maeno T. , Blankenship J. E. 
Published: January 2005

AbstractIn the abdominal ganglion of Aplysia kurodai, three neurons were identified that responded with inhibition of long duration (ILD) to a single stimulation of the siphon nerve and to bath and iontophoretic application of dopamine. The ILD is a long‐lasting (15–60 sec) hyperpolarizing potential, typically associated with a conductance increase but with a reversal potential more negative than the potassium equilibrium potential. Exchange of half the external chloride with acetate induced no change in the ILD. The ILD was reduced in amplitude in the presence of 0.1 normal K+ in the external medium and enhanced in two times normal K+ solution. The ILD amplitude, but not conductance, was progressively impaired by cooling and by the metabolic inhibitors ouabain and strophanthidin. These results suggest that the ILD is composed of an increase in K+ conductance and activity of the electrogenic Na‐pump. Theophylline potentiated the ILD, especially its duration. Furthermore, bath application of dibutyryl cAMP augmented the amplitude of the synaptically elicited ILD and the dopamine responses by 30% over controls without any effect on the change in membrane conductance. Intracellularly injected cAMP also increased the ILD, but 5′‐AMP showed no such effect. These data suggest that dopamine acts on the ILD neurons by increasing K+ conductance and the activity of the electrogenic Na‐pump and that cAMP might selectively stimulate the pump component of the ILD.
Cysteinesulfinate decarboxylase activity as an index of taurine‐containing structures
Authors: Staines Wm. A. , Benjamin A. M. , McGeer E. G. 
Published: January 2005

AbstractThe distribution of cysteinesulfinic acid decarboxylase (CSAD) activity has been studied for some time on the assumption that this activity was a marker for taurine‐containing structures in the CNS. We have found that various in vivo and in vitro treatments of CNS tissues result in parallel changes in the activities of CSAD and glutamic acid decarboxylase (GAD). This suggests that the assay for CSAD is in fact measuring predominantly GAD activity. This hypothesis is tested by lesion, regional distribution, kinetic, inhibitor, and stability studies.
The effect of the repetitive propagation of action potentials on the structure of toad sciatic nerve myelin membranes: An X‐ray diffraction study at 11 Å resolution
Authors: Padrón Raúl , Mateu L. 
Published: January 2005

AbstractEquatorial sections of the x‐ray diffraction patterns of myelin from toad sciatic nerves recorded at 11 Å resolution during long supramaximal repetitive stimulation (240 Hz for two hours) were used to calculate the relative electron density profile of the myelin membranes in this physiological state. The profile was compared to the one determined for the same nerve at rest. The difference between the stimulated profile and the control profile was found to be statistically non‐significant. Therefore, when the sciatic nerve fibers are excited the structure of the internodal myelin membranes does not significantly change at 11 Å resolution.
The K+ liquid ion exchange electrode system: Responses to drugs and neurotransmitters
Authors: Kuramoto T. , Haber B. 
Published: January 2005

AbstractK+ ‐sensitive liquid ion exchange electrode systems respond with a slow potential change to acetylcholine, choline, anticholinergic drugs, biogenic amines, and glutamic acid. The response threshold has been defined, and in most cases it is at extremely low concentrations (10−7–10−;5 M). The direction of the potential change varies, but in most instances it is additive to that produced by external K+. The K+ electrode system is further sensitive to decreasing pH, within a narrow and possibly physiological range of pH. These findings suggest that small measured changes in extracellular K+ are biased by the chemosensitivity of the liquid ion exchange electrode system to some compounds of physiological importance.
Sodium dependence of high affinity glutamic acid transport in cortical synaptosomes—a comparison of Long‐Evans and Sprague‐Dawley rats
Authors: Wheeler D. D. 
Published: January 2005

AbstractThe sodium dependence of high affinity glutamic acid transport has been studied in cortical synaptosomes from Sprague‐Dawley rats and compared to previous studies with Long‐Evans rats. Initial velocity of uptake was measured as a function of both glutamate and sodium concentration, and the data fitted to the rate equations for the same set of models that was utilized in the Long‐Evans studies. The minimal best‐fit model was found to be identical to that found previously for Long‐Evans animals. Thus there are no fundamental differences in the basis of the sodium dependence of high affinity glutamate transport between the two groups.However, since the constants describing the best fit model are different for the two groups of animals, there are quantitative differences in the transport mechanism between the two groups. The rate equation for the minimal best‐fit model permits certain functions to be defined in terms of dissociation and translocation constants, substrate, sodium, and total carrier concentrations. These functions were calculated and then utilized to demonstrate the quantitative differences in the transport mechanism in the two groups.
Effect of essential fatty acid deficiency on the synthesis and turnover of myelin lipid
Authors: Miller Sheldon L. , Klurfeld David M. , Weinsweig David , Kritchevsky David 
Published: January 2005

AbstractThe metabolism of myelin glycerophospholipids as a function of essential fatty acid (EFA) deficiency was studied in rats. Mothers were fed a lipid‐free diet from the eighth day of pregnancy throughout the suckling period. Pups were continued on the diet after weaning. Control mothers and pups were fed the same diet as experimental rats plus 3% corn oil for the same periods. Pups fed the lipid‐free diet had lower total body weight, brain weight, and total myelin phospholipid levels than controls.At 17 days of age, each rat pup was injected with a mixture of [3H]‐glycerol and [1‐14C]‐acetate and were killed up to 80 days after injection. Lipids were extracted from isolated myelin. The 3H/14C ratio for choline, serine, and ethanolamine glycerophospholipids decreased more slowly in experimental rats than in controls, suggesting an alteration in either the turnover of myelin phospholipids or the recycling of phospholipids into myelin. Radiolabelled acyl moieties were isolated from myelin lipids and separated according to the degree of unsaturation. Acyl groups with three double bonds, presumably 20:3 (ω−9), isolated from EFA‐deficient rats appeared to be synthesized from a long‐lived pool of precursor. The relative synthesis of other unsaturated acyl moieties appeared to be the same in both groups of rats. These results indicate that EFA deficiency affects myelin metabolism.
Pool size of CDP‐choline in the brain, heart, and lung of normal and hypoxic guinea pigs
Authors: Alberghina M. , Viola M. , Giuffrida A. M. 
Published: January 2005

AbstractThe pool size of CDP‐choline in the brain, heart, and lung of normal and hypoxic animals was measured by radioactive isotopic dilution. The effect of exogenous CDP‐choline administration on the pool size in these experimental groups was also examined. The hypoxic treatment caused a significant decrease of endogenous CDP‐choline in the brain and lung only; no significant effect was observed in the examined organs after CDP‐choline treatment.
Ultrastructural changes accompanying the growth of isolated oligodendrocytes
Authors: Wollmann R. L. , Szuchet S. , Barlow J. , Jerkovic M. 
Published: January 2005

AbstractThe changes in the ultrastructure of oligodendrocytes with time in culture were examined by transmission electron microscopy. Oligodendrocytes were isolated from ovine white matter and maintained in Dulbecco's modified Eagle's medium supplemented with 20% horse serum. One day after being placed in plastic culture dishes, most cells aggregate into clusters that do not attach to the surface for several days. Cells within these clusters form junctional complexes resembling gap junctions, their nuclear chromatin becomes uniformly dispersed, they are rich in polyribosomes, and their cytoplasm is less osmiophilic than oligodendrocytes in ovine white matter or cells fixed immediately after isolation. At this time, the cells in culture fit the description of light oligodendrocytes. After several days in culture, the cells become attached to the plastic surface, chromatin once again becomes clumped beneath the nuclear membrane, rough endoplasmic reticulum accumulates within the cytoplasm and the cells extend long processes containing cytoplasmic organelles. From these observations, it appears that oligodendrocytes undergo a transient dedifferentiation during their recovery from the trauma of isolation, not unlike the central chromatolysis seen in neurons following axonal injury. After acclimatization to tissue culture conditions, isolated oligodendrocytes show many of the morphologic features seen in vivo and therefore offer a good model to study myelination.
Studies in neuronal ceroid‐lipofuscinosis: Heterogeneous nature of neuronal autofluorescent lipopigments
Authors: Garg Hari S. , Awasthi Yogesh C. , Srivastava Satish K. 
Published: January 2005

AbstractA method has been developed for the complete extraction and fractionation of the autofluorescent lipopigments present in the neuronal tissue of Batten‐Spielmeyer‐Vogt (BSV) patient and normal subject, respectively. The fluorescent lipopigments that were about three‐fold higher in BSV patient's brain as compared with normal subjects were separated into at least 7 fluorometrically and chromatographically distinct fractions by thin layer chromatography (TLC). Although the fluorescent lipopigments of the brain tissue of BSV patient and normal subject showed identical pattern of separation on TLC, the fluorescence spectra of the individual lipopigment fractions from BSV patient was different from those of the corresponding fractions from the normal subject. The ultraviolet spectral studies with individual fluorescent lipopigment fractions indicated the presence of highly unsaturated conjugated chromophore.
Proliferation of glial‐derived cells in defined media
Authors: Michler‐Stuke Angelika , Bottenstein Jane E. 
Published: January 2005

AbstractA serum‐free defined medium has been formulated that supports proliferation and morphologic differentiation of U‐251 MGsp human and C6‐2BD rat glioma cells. This defined medium consists of a basal medium supplemented with transferrin, fibroblast growth factor, hydrocortisone, selenium, biotin, and fibronectin (G2 medium). When U‐251 cells were plated in G2 medium on poly‐D‐lysine precoated dishes, their growth rate was 77% and final cell density was 82% of serum‐grown counterparts. The growth rate of C6 cells in G2 medium was 67% compared to cells cultured in serum supplemented medium. Although G2 medium supported the growth of human and rat glioma cells, LA‐N‐1 human neuroblastoma and WI‐38 human fibroblast cells showed no increase in cell number when grown in G2 medium compared to basal medium. A similar formulation (G3 medium), lacking fibroblast growth factor and hydrocortisone, supported the proliferation of RN‐22 rat schwannoma cells. Morphologic differences were observed between cells grown in the presence of serum and in defined media. All three glial cell lines changed from a flattened shape in serum supplemented medium to a more spherical appearance in defined medium. In addition, both U‐251 and C6 cells developed numerous processes, some reaching several cell diameters in length. These defined media will facilitate studies of the growth and differentiation of glial‐derived cells.