bluuebunny/crossref_metadata_2025_split huggingface dataset:
Failure to demonstrate alterations in gluconeogenesis in growth‐retarded weanling rats with dorsomedial hypothalamic lesions
Authors: Bernardis Lee L. , Goldman Jack K. , Bellinger Larry L. 
Published: January 2005

AbstractBilateral electrolytic lesions were placed in the dorsomedial hypothalamic nuclei (DMN) of weanling male Sprague‐Dawley rats. Sham‐operated rats served as controls. After 22 days on lab chow and tap water ad libitum, the animals were injected with U‐14 C‐alanine 0.167 μC/μ moles intraperitoneally (5 μC and 30 μ moles/100 gm body weight) and sacrificed 2 hr later. There was no significant difference, in the incorporation of the label into total lipid, free fatty acids, glycogen, or tissue protein of both liver and diaphragm, between the DMN‐lesioned and the sham‐operated rats. Similarly, there was no significant difference in the incorporation into the plasma glucose or protein. It is concluded that in spite of profound alterations in both ponderal and linear growth and food intake, there is no disruption of normal gluconeogenesis in the weanling rat with DMN lesions.
The relationship of afterhyperpolarizations of extraocular motoneurons to membrane potential
Authors: Barmack N. H. 
Published: January 2005

AbstractThe effect of membrane potential displacements caused by external current injection on the amplitudes of two antidromically evoked afterhyperpolarizations (AHP1 and AHP2) was measured in extraocular motoneurons. AHP1 had a reversal potential of –70m V and an average compensation for displacements from the reversal potential (“compensation gain”) of –0.36. AHP2 had a reversal potential of –80mV and a compensation gain of –0.08. Measurements of input resistance of these motoneurons demonstrate a 30–50% decrease at depolarized membrane potentials. This rectification could account for the apparent lack of summation of AHP2. The functional role of AHP1 and AHP2 in the regulation of discharge frequencies of extraocular motoneurons during normal eye movements is discussed.
Failure of hepatic infusion of amino acids and/or glucose to inhibit onset of feeding in the deprived dog
Authors: Bellinger L. L. , Birkhahn R. H. , Trietley G. J. , Bernardis L. L. 
Published: January 2005

AbstractNine mongrel dogs were fed for only 1 hour/day for 7–8 days and the time of onset of their eating and hourly intakes were recorded. At the end of this period, the hepatic portal vein was cannulated and the polyethylene cannula was exteriorized. Upon recovery to their preoperative food intake, the dogs were infused after a 23 hour fast over a 4 minute period with an amino acid (AA) mixture (FreAmine II, McGaw Laboratories) equal to 7.2% (37 trials), 14.4% (28 trials), or 21.6% (28 trials) of the dogs' daily AA requirements and presented with food 4 minutes later. In all 93 trials the dogs ate within 30 seconds of presentation of food and their hourly intakes were not significantly different from isotonic saline infusions. Six 23 hour deprived dogs were infused with 21.6% of their AA requirement and then presented with food 11 minutes later. Again, these dogs began eating within 30 seconds of presentation of food. Finally, 4 dogs were infused over a 4 minute period after a 23 hour fast (12 trials) with 7.2% of their daily AA requirements mixed with 6 g of glucose and presented with food 4 minutes later. The dogs began eating within 30 seconds in all 12 trials and their hourly intakes were not significantly depressed. These results question the existence or role of hepatic glucoammonium receptors involved in the control of feeding behavior.
Binding and immobilization of catecholamines by liposomes
Authors: Hoss Wayne , Smiley Constance 
Published: January 2005

AbstractThe polarization of the native fluorescence of dopamine and noradrenaline has been used to measure their binding and immobilization by liposomes suspended in aqueous buffers. Whereas both catecholamines are significantly immobilized by brain phosphatidyl serine and yeast phosphatidyl inositol, phosphatidyl ethanolamine and phosphatidyl inositol from brain are ineffective. Dopamine is immobilized to a greater degree than noradrenaline. The dissociation constants determined from modified Scatchard plots of the polarization data are 1.7 × 10−4 and 9.6 × 10−5 M for dopamine with yeast phosphatidyl inositol and brain phosphatidyl serine, respectively. Apomorphine binds to a hydrophobic region of phosphatidyl serine liposomes with a KD value of 69 μM. It is suggested that a fraction of dopamine is complexed with membranous phosphatidyl serine in nerve terminals.
Bacterial lipopolysaccharide depresses spontaneous, evoked, and ionophore‐induced transmitter release at the neuromuscular junction
Authors: Person Robert James 
Published: January 2005

AbstractThe neurotoxicity of RNA‐free lipopolysaccharide (LPS) extracted from Salmonella Typhimurium (SR‐11) was tested at the frog neuromuscular junction using intracellular recording techniques. Spontaneous miniature endplate potential (MEPP) frequency was reduced to 45% of control after 60 minutes in the presence of 10 and 50 μg LPS/ml Ringer's solution. Elevation of extracellular [Ca] to 10 mM converted the MEPP frequency response to a biphasic pattern of early acceleration followed by late depression. Evoked endplate potentials (EPPs) were reduced in quantal content until phasic release of transmitter was abolished, while MEPP amplitude and endplate resting potential remained constant. Effects of the potent cation ionophore X537A on MEPP frequency were blocked by 45 minutes of pre‐exposure to LPS. Because of its extremely lipophilic character, LPS apparently alters the physical structure of the presynaptic terminal membrane, eventually reducing resting and phasic Ca influx, and isolating the presynaptic terminal from ionophore action.
Effects of the lateral septum and latent inhibition on successive discrimination learning
Authors: Toga Arthur W. , Burton Howard A. 
Published: January 2005

AbstractDamage to the lateral nucleus of the septum in the rat resulted in atypical learning to a previously meaningless stimulus. Nonreinforced preexposure to a stimulus normally makes more difficult subsequent use of that stimulus for learning. The effect of this preexposure on learning is termed latent inhibition and was demonstrated in sham operated animals. Rats in which the lateral septum was damaged demonstrated a paradoxically smaller learning deficit in the presence of a conditioned stimulus that was previously presented without reinforcement, when compared to the performance of both septal lesioned rats not receiving nonreinforced preexposure and sham operates receiving preexposure. The interaction of nonreinforced preexposure and lateral septal lesions can be explained using a proposed sensitization hypothesis.
The interrelation between brain PO2 and NADH oxidation‐reduction state in the gerbil
Authors: Mayevsky A. , Lebourdais S. , Chance B. 
Published: January 2005

AbstractThe present investigation was aimed at studying the interrelation between hemodynamic, metabolic and oxygen tension in the brain of the gerbil exposed to various physiological and pathological conditions in the awake and anesthetized states. The hemodynamic and metabolic activities were evaluated by the DC fluorometer/reflectometer and were correlated to the pO2 values obtained by a surface electrode.When the awake brain was exposed to spreading depression (SD), a typical oxidation cycle of the NADH was recorded concomitant with a decrease cycle of the pO2. Under anesthetic effect the same dip in pO2 response was found but the NADH showed a “reduction cycle.” The pO2 values were in a very good correlation with the changes in the reflectance trace, namely, the pO2 was a good indicator of the vasoconstriction‐vasodilatation responses under various conditions. The same model was used under hypoxic and ischemic conditions, as well as under the effects of anesthetics.
Glutamic acid transport in cortical synaptosomes from essential fatty acid deficient rats
Authors: Wheeler D. D. , Callihan C. S. , Wise W. C. 
Published: January 2005

AbstractThe sodium dependence of the high‐affinity transport of glutamic acid in rat brain synaptosomes has been studied in animals maintained on a diet deficient in essential fatty acids (EFAD), and the results compared to similar studies with animals on a normal diet. Although the data give best fit to the same kinetic model as for control data, there are differences in the constants that describe the model. Except at low sodium concentrations, uptake is lower for the EFAD group.As a consequence of the differences in constants for the two groups, there are quantitative differences in the transport mechanism. The rate equation for the best fit model has been utilized to define certain functions in terms of dissociation and translocation constants, glutamate, sodium, and total carrier concentrations. These functions were calculated and utilized to compare the transport mechanism for the two groups. Although there are differences between these functions for control and EFAD animals, these differences are small and therefore of doubtful physiological significance.
Effect of methionine, glycine and serine on serine hydroxymethyltransferase activity in rat glioma and human neuroblastoma cells
Authors: Kohl Randall Lee , Perez‐Polo J. R. , Quay W. B. 
Published: January 2005

AbstractHuman neuroblastoma SK‐N‐SH‐SY5Y (5Y) and rat glioma (C6) cells were cultured with supplemental methionine, glycine, or serine for three to six days. Serine hydroxmethyltransferase (SHMT: L‐serine: tetrahydrofolate 5, 10‐hydroxymethyltransferase, EC 2.12.1) was assayed radiometrically in whole cell homogenates, crude supernatant fractions and crude particulate fractions. No significant changes in specific activity or cellular morphology were noted at methionine, glycine, or serine concentrations up to 16 mM. Serine concentrations of 20 and 40 mM led to significantly lower gliomal enzyme specific activities. This activity was unevenly distributed between soluble and particulate fractions, with 190 and 398 nmoles of HCHO formed per mg of protein per hour, respectively. Growth stage and time of incubation were major determinants of enzyme specific activity. C6 cells' specific activity rose slowly with increasing time in culture until cellular confluence. At this time there was a pronounced elevation in specific activity, occurring more rapidly in cells grown in 1.2 mM methionine. Intracellular amino acid analysis of C6 cells demonstrated a significant rise in methionine after four days in media containing 0.2 mM methionine. No appreciable diminution in the intracellular levels of glycine or serine occurred following incubation in excess methionine.It is concluded that SHMT‐specific activity in C6 and 5Y cells is not regulated by glycine, serine, or methionine levels and that high concentrations of these amino acids (> 30 mM) are not detrimental to these cells derived from the CNS.
Studies on AMP deaminase and 5′‐nucleotidase in rat brain under different experimental conditions
Authors: Sadasivudu B. , Rao T. Indira , Murthy Ch. Radhakrishna 
Published: January 2005

AbstractAdenosine monophosphate (AMP) deaminase and 5′‐nucleotidase, the two enzymes involved in the disposal of AMP, have been detected in different regions of normal rat brain and in animals subjected to heightened neuronal activity (leptazol‐induced convulsions) and to depression of the central nervous system (CNS) by the administration of barbiturates. They have also been estimated in the CNS of animals subjected to anoxia or treated with lithium and ammonium salts. The AMP deaminase activity was found to be highest in cerebellum and lowest in cerebral cortex, while the 5′‐nucleotidase activity was found to be highest in brain stem and lowest in cerebellum. The AMP deaminase activity was elevated in all the regions of brain during the preconvulsive and convulsive periods. The activity returned to normal during recovery. The activity of 5′‐nucleotidase was found to be depressed in the preconvulsive and post‐convulsive periods. The enzyme was also found to be depressed in all three regions after the administration of barbiturates. Administration of lithium or ammonium salts or induction of anoxic states resulted in an increase in the activity of AMP deaminase in all the three regions of brain. These results are discussed in relation to the probable production of cyclic AMP and cyclic guanosine monophosphate (GMP) which may have depressive and excitatory roles, respectively, in brain. It appears that increased AMP deaminase activity is associated with increased neuronal activity while depression of 5′‐nucleotidase activity is associated with conditions of decreased CNS excitability.
Simultaneous fluorescent retrograde axonal tracing and immunofluorescent characterization of neurons
Authors: Van Der Kooy Derek , Steinbusch Harry W. M. 
Published: January 2005

AbstractA simple method is described for simultaneously double labeling single neurons with fluorescent retrograde axonal tracers and immunofluorescence using an antibody to serotonin. Caudate‐putamen injection of orange fluorescent propidium iodide, in particular, proved effective in retrogradely labeling dorsal raphe cell bodies. These same perikarya could be stained green with the indirect immunofluorescent method, using green fluorescent fluorescein isothiocynate (FITC) as the second antibody.
Axoplasmic transport with velocities induced by pargyline
Authors: Watson Danny F. , Donoso J. Alejandro , O'Neill Robert E. , Samson Fred E. 
Published: January 2005

AbstractThe axoplasmic transport of proteins in spinal motor neurons is altered by pargyline, a drug that causes increased release of monoamines. Two new peaks of transported protein were detected in the sciatic nerves of rats treated with pargyline (75 mg/kg/day ip for three days). These peaks moved with velocities of 595 mm/day (peak I) and 1,230 mm/day (peak II). The bulk of labeled protein was still transported at the control rate of 362 mm/day. Electrophoresis of transported polypeptides labeled with [35S] methionine showed that peak I material was qualitatively similar to material transported at the normal rate in controls, but peak II material contained fewer labeled polypeptides. Both peak I and peak II differed from controls in the relative intensity of labeling of various polypeptides. Fast axoplasmic transport in sensory neurons was unaffected by pargyline. Intraspinal injection of pargyline (50 μg/day for three days) caused changes in axoplasmic transport similar to those induced by intraperitoneal pargyline. These results show that transport of certain proteins along a peripheral nerve can be accelerated by a mechanism initiated in the region of the nerve cell bodies.
Inhibition of neurotransmitter receptor binding by ergot derivatives
Authors: Hruska Robert E. , Silbergeld Ellen K. 
Published: January 2005

AbstractBromocriptine, lergotrile, lisuride, metergoline, and the Sandoz ergot derivatives 25–397, 29–712, and 29–717 have been tested for their ability to inhibit the synaptic receptor binding of spiroperidol, 5‐hydroxytryptamine (5‐HT), d‐lysergic acid diethylamide (LSD), quinuclidinyl benzilate (QNB), WB.4101, and γ‐aminobutyric acid (GABA). Only GABA binding was not affected, and QNB binding was decreased only by lergotrile and metergoline at high concentrations. The most potent inhibitors of the other ligands were bromocriptine and lisuride for spiroperidol (1–2 nM), metergoline for 5‐HT (29 nM), lisuride for LSD (15 nM), and lergotrile for WB.4101 (17 nM). The direct receptor effects of the ergot derivatives in vitro may contribute to understanding their in vivo effects on behavior and in predicting their therapeutic potential in neurological and neuroendocrine disorders.
Specific enhancement of neuronal responses to catecholamine by p‐tyramine
Authors: Jones Roland S. G. 
Published: January 2005

AbstractExtracellular recording and iontophoresis techniques were used to study the interactions of the trace amine, p‐tyramine (p‐TA) with putative neurotransmitters on single neurones in the cerebral cortex and caudate nucleus of the rat. p‐TA, when applied with weak iontophoretic currents which did not result in any change in neuronal firing rate, caused a pronounced potentiation of depressant responses to iontophoretically applied dopamine (DA). Depressant responses of cortical neurones to noradrenaline were also markedly potentiated by weak background applications of p‐TA. This potentiating action of p‐TA was related to the amount of the trace amine applied and was apparently specific for catecholamines, since depressant responses to 5‐hydroxytryptamine and γ‐aminobutyric acid were unaffected. Excitatory responses to iontophoretically applied glutamate were also unaltered by weak applications of p‐TA. Excitatory responses of most neurones to acetylcholine (ACh) were also unaffected by p‐TA in the cortex and caudate nucleus. However, responses to ACh of a small number of cells in both brain areas were reduced in size during weak applications of p‐TA. It is suggested that p‐TA may act as a modulator of neurotransmission, particularly that mediated by DA in the central nervous system.
Horizontal cell processes in teleost retina
Authors: Parthe V. 
Published: January 2005

AbstractContacts between horizontal and bipolar cells are described in the retina of the teleost Eugerres plumieri. A single, long expansion observed in the external cone horizontal cells makes contact by means of a terminal button with the cell body of a bipolar. It represents the only contact between this class of horizontal cell and the bipolar soma. On the other hand, the medial and internal cone horizontal cells and the rod horizontal cells, which lack such a single, long expansion, display instead numerous short and fine expansions that terminate by means of a terminal knob on a bipolar cell body. The bipolar‐destined, short expansions of the rod horizontal cell make contact with large bipolar cell bodies, whereas corresponding short expansions of cone horizontal cells contact small bipolar cell bodies.It is suggested that the ascending horizontal cell process forms presynaptic terminals in the photoreceptor triad complex, and that the single, long and the multiple, short bipolar‐destined expansions are postsynaptic to the bipolar cell body.
A new antigen common to the rat nervous and immune systems: I. Detection with a hybridoma
Authors: Akeson Richard , Graham Karen L. 
Published: January 2005

AbstractAn antibody secreting cell line has been obtained using the technology developed by Milstein, Kohler, and colleagues by fusion between ×63 myeloma cells and spleen cells from a mouse previously immunized with PC12 cultured rat pheochromocytoma cells. This antibody bound to particulate protein from adult rat brain and to a lesser extent spinal cord and retina but not adrenal. Lower levels of binding were observed also with spleen, bone marrow, and peritoneal exudate cells. Cells or particulate protein from seven nonneural, nonimmune tissues showed essentially no specific binding. Analysis of adherent and nonadherent peritoneal exudate cells indicated specific antibody binding to both populations. The specific antibody bound was greater in the non‐adherent fraction. The antigen has been provisionally named G5 after the antibody secreting clone. Like the Thy 1 antigen of rodents, it is expressed by subpopulation of cells from the nervous and immune systems. However the antigen could not be detected on the PC1 2 cell line used for immunization suggesting that Balb/C mice spontaneously produce antibody to this rat differentiation antigen.
Purification of dihydropteridine reductase from human platelets
Authors: Shen Rong‐Sen , Abell Creed W. 
Published: January 2005

AbstractDihydropteridine reductase was purified approximately 1,700‐fold from human outdated blood platelets. Two forms of the enzyme, A and B, were resolved. They have the same Km values for 2‐amino‐6,7,‐dimethyl‐4‐hydroxydihydropteridine (46 μml;M vs 49 μml;M), but the A form has a Km for NADH that is two times higher than that of the B form (20 μml;M vs 9 μml;M).
The effect of injections of dopaminergic agonists into the caudate nucleus on the electrocorticogram of the rat
Authors: Keane P. E. , Neal H. 
Published: January 2005

AbstractElectrocortical activity was recorded in encéhale isolé rats during injection of various dopaminergic compounds into the caudate nucleus. Slow waves and spindles were observed following injection of compounds with different mechanisms of action in stimulating the dopamine receptor. Some arylalkylamine analogues also induced similar electrocortical changes, whereas others were inactive. The possible dopamine agonist activities of these compounds are discussed. The results support an involvement of dopamine in the production of electrocortical slow waves and spindles.
Reorganization and orientation of regenerating nerve fibres, perineurium, and epineurium in preformed mesothelial tubes – an experimental study on the sciatic nerve of rats
Authors: Lundborg Göran , Dahlin Lars Bertil , Danielsen Nils P. , Hansson Hans Arne , Larsson Karin 
Published: January 2005

AbstractRegeneration of severed peripheral nerves is unfortunately often incomplete, due to loss of nerve fibers and neuroma formation. A new approach is presented with the intention of improving the conditions for nerve repair. In the first of the two stages, a pseudosynovial tube is formed around a silicone rubber rod, surrounded by a stainless steel spiral, which was placed in the backs of rats. This tube, in the second stage, is used as a free “tube graft” to bridge gaps of about 10–12‐mm lengths in the severed sciatic nerve. The tube was kept open by the metal spiral. Regenerating nerve fibers with their sprouts grew into the initially open space in the tube. A new nerve trunk was formed, comprised of closely packed myelinated and unmyelinated axons, organized into fascicles. Demonstration by electron microscopy and by EMG recording of reinnervation of foot muscles supported successful long‐term results. The fascicles were delimited by perineurial and epineurial sheaths and, furthermore, showed signs of maturation. It was also demonstrated that the nerve‐fiber regeneration ceased after a few weeks if there was no distal nerve inserted into the tube. The importance of optimizing the interaction between local factors and regenerating nerve fibers for reestablishment of functionally valuable motor units is discussed.
Effects of neurotransmitters on calcium efflux from cultured glioma cells
Authors: Lazarewicz Jerzy W. , Kanje Martin 
Published: January 2005

AbstractThe effects of various neurotransmitters and cyclic nucleotides on 45Ca2+ efflux in cultured human glioma cells were investigated. Glutamate and glycine, but not GABA, stimulated 45Ca2+ release from the cells.Stimulation of beta‐adrenergic receptors but not alpha‐adrenergic receptors also increased 45Ca2+ efflux. Cholinergic receptor stimulation by carbachol had the same effect. The stimulatory effect of carbachol was abolished in the presence of either atropine or hexamethonium.C‐AMP and c‐GMP increased the 45Ca2+ efflux, suggesting that these agents are involved in the transmitter‐stimulated release of 45Ca2+ from the cells.Kinetic analysis of the efflux revealed four calcium compartments. The carbachol‐stimulated efflux represented a net release of calcium and could be ascribed to the slowest compartment.The physiological role of the transmitter‐stimulated calcium release is discussed in terms of calcium‐regulated stimulus‐response coupling in glial‐neural interaction during excitation.