bluuebunny/crossref_metadata_2025_split huggingface dataset:
Elevated endogenous GABA level correlates with decreased fMRI signals in the rat brain during acute inhibition of GABA transaminase
Authors: Chen Zhengguang , Silva Afonso C. , Yang Jehoon , Shen Jun 
Published: January 2005

AbstractVigabatrin and gabaculine, both highly specific inhibitors of GABA (γ‐aminobutyric acid) transaminase, cause significant elevation of endogenous GABA levels in brain. The time course of GABA concentration after acute GABA transaminase inhibition was measured quantitatively in the α‐chloralose‐anesthetized rat brain using in vivo selective homonuclear polarization transfer spectroscopy. The blood oxygenation level‐dependent (BOLD) effect in functional magnetic resonance imaging (fMRI) has been considered to be coupled tightly to neuronal activation via the metabolic demand of associated glutamate transport. Correlated with the rise in endogenous GABA level after vigabatrin or gabaculine treatment, the intensity of BOLD‐weighted fMRI signals in rat somatosensory cortex during forepaw stimulation was found to be reduced significantly. These results are consistent with previous findings that inhibition of GABA transaminase leads to augmented GABA release and potentiation of GABAergic inhibition. © 2004 Wiley‐Liss, Inc.
The effect of the chronic administration of D‐amphetamine upon circadian changes in amino acids in the pineal and pituitary glands of the rat
Authors: Leonard B. E. , Neuhoff V. , Tonge Sally R. 
Published: January 2005

AbstractThe formation of dansyl derivatives of amino acids, 5‐hydroxyindoleacetic acid and histamine, and their separation on polyamide plates provides a reliable and sensitive method for studying circadian changes in single pineal and pituitary glands of the rat. There appears to be no correlation between the circadian changes in concentrations of these substances in the pineal and pituitary glands.Chronically administered D‐amphetamine altered the circadian rhythms of five amino acids in the pituitary, including the putative transmitters taurine, glycine, and glutamate; in the pineal gland only the rhythmical changes of lysine and 5‐hydroxyindoleacetic acid were affected.
Six‐month follow‐up in weanling rats with ventromedial and dorsomedial hypothalamic lesions: Somatic, endocrine, and metabolic changes
Authors: Bernardis L. L. , Goldman J. K. , Chlouverakis C. , Frohman L. A. 
Published: January 2005

AbstractThus far both the weanling rat ventromedial and dorsomedial syndrome have been investigated in only two and three‐week studies. The present data are derived from a six‐month study. Food intake and body weight and length changes were recorded weekly or bi‐weekly and endocrine and metabolic parameters were assessed at sacrifice. Rats that had received ventromedial hypothalamic lesions shortly after weaning showed all the changes noted in previous short‐term studies, i.e. normal body weight gains and food intake but increased carcass fat content. In addition, they manifested a slight hyperglycemia, normal free fatty acid levels and slowing‐down of lipogenesis. Rats that had received dorsomedial lesions shortly after weaning also showed changes previously reported in short‐term experiments. These include reduced ponderal and linear growth and food intake, but normal carcass composition and growth hormone levels. In addition, they showed a slight improvement of hypophagia with time, and at sacrifice hypoglycemia and low free fatty acid levels. Incorporation of glucose into fat pad glycogen and CO2 was decreased. In diaphragm, glucose incorporation was increased in both total lipid and fatty acids. The data demonstrate that both hypothalamic syndromes change with time, but not necessarily in a progressive manner. They also show that destruction of two so closely appositioned hypothalamic structures brings about entirely differnt and, in some parameters, opposite changes.
Difference in occipital cortical synapses from environmentally enriched, impoverished, and standard colony rats
Authors: Diamond Marian C. , Lindner Bernice , Johnson Ruth , Bennett Edward L. , Rosenzweig Mark R. 
Published: January 2005

AbstractInitial and replication experiments were studied with littermate, S1, male rats 25–55 days of age placed in enriched (EC), standard colony (SC), and impoverished (IC) environments. Measurements of the length of postsynaptic thickenings were taken from asymmeterical axodendritic synapses in layer IV of the dorsal medial occipital cortex. This experiment differed from others of this nature, for animals from both experimental conditions were compared with the standard colony animals. The 8% (p < 0.01) difference in postsynaptic thickening length between 675 synapses from EC and 680 synapses from IC was primarily due to the IC, as can be seen by comparing both with the SC.The number of synapses per unit area of neuropil was 15% (p< 0.01) more in the IC than in the EC and this difference was primarily due to impoverishment. Both the original and the replication experiment verified this direction of change. Thus, environmental experience does significantly affect synaptic length and number, although the large magnitude previously reported by Møllgaard et al. (1971) was not confirmed in the present experiments. The 7% cortical depth difference between the enriched and impoverished animals was seen to be attributed to both conditions when each was compared with the standard colony rats. The plasticity of synaptic dimensions is discussed in relation to our previous work and to work of others.
Somatic evoked response components and recovery functions in subjects with mu and alpha rhythms
Authors: Velasco Marcos , Berrondo Luisa , Olvera Alfredo , Velasco Francisco 
Published: January 2005

AbstractSubject with prominent rolandic mu and alpha rhythms showed similar late somatic evoked response (SER) components but different SER recovery functions.A late P5x component was present when SER were superimposed on mu and alpha rhythms spontaneously recorded from the rolandic region of inattentive individuals. Since P5x was not present in other inattentive subjects unless SER were superimposed on a rhythmic rolandic activity evoked by an attentive situation, it seems reasonable to assume that the p5x component is partially due to spontaneous or evoked rolandic EEG rhythmicity.In addition, single propioceptive stimuli produced blocking of mu rhythm and a flat recovery function of the P5a component. In contrast, similar stimuli produced an enhancement of alpha rhythm and periodic amplitude modulation curve of the P5a component. These results suggest that the P5a component is mediated by the same neurophysiological mechanisms which block or modulate the spontaneous rolandic EEG rhythms.
Studies on neuronal lipid
Authors: Tamai Yoichi , Araki Shigeko , Komai Yuichi , Satake Mei 
Published: January 2005

AbstractThe procedure for bulk preparation of nerve‐cell perikarya from pig brain‐stem is briefly described. This method has definite merits with regard to the preservation of the intracellular structures as well as the preservation of the processes.The chemical composition of the isolated nerve‐cell perikarya is presented. The nerve‐cell perikarya are characterized by the absence of cerebroside and sulfatide. Diffuse distribution of ganglioside on the cell surface is suggested. The lipid content of the nerve‐cell perikarya isolated by different methods is discussed.Lipid composition of the invertebrate nervous tissue is discussed.The submicrosomal membranes of rat brain are isolated, and their chemical and morphological properties are discussed. Ribosome‐free membranes are characterized by the high content of glycolipids including gangliosides, as well as by the high activity of Na, K‐ATPase, whereas ribosome‐bound membranes are characterized by the absence of glycolipids, as well as by the low activity of Na, K‐ATPase. The molecular organizations of lipid in submicrosomal membranes are demonstrated.
Comparison of visual and tactile learning in octopus after lesions to one of the two memory systems
Authors: Bradley E. A. , Young J. Z. 
Published: January 2005

AbstractSets of animals with lesions to either the vertical lobe or median inferior frontal lobe were trained first visually and then by touch. Lesions of the vertical lobe system did not affect the increase produced by food in tendency to attack a moving figure in the visual field. Any lesion that interrupted the circuit through the vertical lobe greatly impaired the capacity to inhibit attacks on crabs when these attacks resulted in shocks. Removal of the median inferior frontal lobe did not impair this capacity to learn not to attack a crab in the octopus's visual field.The Capacity to learn to respond positively to a black disc but to avoid a white one was grossly impaired by an interruption of the vertical lobe circuit. After such operations the animals showed a strong preference for white over black. The capacity to learn to discriminate between black and white was not affected by removal of the median inferior frontal lobe. Animals with interruptions of the vertical lobe circuit could learn to make discrimination between white as a positive figure and black as a negative one, but they made more mistakes than controls. Most mistakes consisted of attacks on the negative (black) figure, but there were also some failures to attack the white.In tactile discrimination between rough and smooth spheres given successively, animals with vertical lobe lesions were, under some circumstances, less accurate than controls. They took more objects than controls. They were less able than controls to reverse the discrimination. After removal of the median inferior frontal lobe tactile discrimination was greatly impaired. The animals showed a strong preference for rough objects and could not learn to take smooth objects. However, they showed improvement in discrimination when trained with smooth negative and are therefore not wholly incapable of long‐term memory storage.
In vivo measurement of 32P in the brain of a freely moving rat
Authors: Mayevsky A. , Samuel D. , Friedland S. S. , Ewins J. H. 
Published: January 2005

AbstractA new method for measuring the uptake of materials labeled with radioactive phosphorus (32P) in the brain of a freely moving rat is described. The rat of uptake in the brain of a single animal of 32P‐labeled phosphate was compared to the uptake rate in the animal's blood or liver. A comparison was made between the uptake following an intravenous (IV) or an intraperitonel (IP) injection. The effect of convulsions caused by injections of metrazol on the kinetics of 32P uptake in the brain is described.
Associative recall and formation of stable modes of activity in neural network models
Authors: Wigström Holger 
Published: January 2005

AbstractModels of neural networks with recurrent inhibition are studied, as well as one model which also includes recurrent excitation. The models are intended as possible descriptions of the cerebral cortex.Each network model is composed of neuron models called pyramidal cells and stellate cells in accordance with the names of two types of cells in the cortex. Inputs and outputs of the network are connected to the pyramidal cells while feedback is provided by the stellate cells. Connections within the network are random.During a learning phase the pyramidal cell excitatory synapses become facilitated according to a two‐ conditional facilitation rule. This is the basis of the model's ability for associative learning. The associative retrieval of information can be studied during a subsequent association phase. This has been done by simulation on a digital computer.It was shown that all of the models considered can be designed to perform a so‐called decision‐making function. This means that if the associating input pattern is similar to several patterns which occurred during learning the model can decide which similarity is greatest by responding with the appropriate associated pattern.The model also including recurrent excitation differs from the simpler models in that it can become stabilized in so‐called stable modes of activity which are self‐sustaining and remain even after the input has been turned off. Normally, only one stable mode can be active at a time. However, through careful choice of construction parameters it was possible to obtain a model in which a maximum of two stable modes could be activated independently of each other.Physiological and psychological interpretations are discussed and so are the limitations of the models, which are evident in certain situations.
Neuronal control of neurotransmitters biosynthesis during development
Authors: Giacobini Ezio 
Published: January 2005

AbstractStudies on neuronal control mechanisms of neurotransmitters biosynthesis during the development of peripheral and centralautonomic synapses are reviewed. Particular emphasis is placed on investigations of developing peripheral sympathetic ganglia and brain in chick embryo and chick.Studies on the development of autonomic neurons and synapses under different pharmacological conditions are reported. Principally the effect of (a) the administration of drugs and precursors such L‐dopa, 3H‐dopa, 6‐OH dopa; (b) the prenatal administration of reserpine; (c) the blockade of cholinergic receptors; (d) the nerve growth factor (NGF) is analyzed.Results of developmental studies on chick ciliary ganglia are summarized.The review particulary underlines the importance of combining the use of sensitive microchemical methods to pharmacological tools in exploring the development of regulatory mechanisms at the cellular level.
Food intake of weanling rats with lesions in the ventromedial and dorsomedial hypothalamic nuclei in response to intragastric loading and caloric density manipulation
Authors: Bernardis Lee L. , Border John R. 
Published: January 2005

AbstractMale rats received bilateral electrolytic lesions shortly after weaning in the ventromedial (VMN) and dorsomedial (DMN) hypothalamic nuclei, respectively. A third group of rats served as sham‐operated controls. The animals were subjected to intragastric preloading with 33% d‐glucose and egg‐white solutions and a 33% corn‐oil suspension, and ad libitum feeding was assessed hourly for the first 7 hr after preloading. The pattern of food‐intake depression was similar in all groups but the quantitative greatest depression was found in the DMN rats. The response of these three groups of animals to a diet diluted with 20% alpha cell, a nonnutritive bulker, showed an initial failure to meter calories by both VMN and DMN rats which, however, was compensated for during the remainder of the 24‐hr test period. In response to a 50% glucose‐chow mixture, both VMN and DMN rats, as well as the controls, showed the same pattern and behaved like mature dynamic hyperphagic rats inasmuch as they did not eat more of this mix than of the standard diet. After a 48‐hr fast, both VMN and DMN rats showed refeeding hypophagia rather than hyperphagia. The data suggest that Panksepp's contention that the VMN in the mature rat is involved in long‐term satiety regulation may be extended to the weanling rat with VMN destruction. Thus, this controlling role appears established early in ontogeny.
Glucose preference and caloric regulation in weanling rats with ventromedial and dorsomedial hypothalamic lesions
Authors: Bernardis Lee L. , Border John R. 
Published: January 2005

AbstractWeanling male rats received electrolytic lesions in the ventromedial (VMN) and dorsomedial (DMN) hypothalamic nuclei, respectively. A third group of rats served as sham‐operated controls (CON). After the two hypothalamic syndromes had been well established, the animals were subjected to (1) a glucose preference test assessing the choice between a 10% w/v and a 35% w/v d‐glucose solution, and (2) a test examining the anorexigenic effect of intraperitoneally injected glucose. Weanling rats with VMN lesions, like their mature counterparts, consistently preferred the stronger over the weaker glucose solution throughout the experiment (16 days). Weanling DMN rats, on the other hand, showed a bimodal response, initially like that of the CON rat, toward the end of the experiment, like that of the VMN rats. The weanling CON animals behaved differently from their mature counterparts, inasmuch as their preference for the dilute solution became evident only toward the latter part of the test. An analysis of the calorie intake shows that calories from glucose are similar in all three groups of rats, that the pattern and magnitude of caloric intake in DMN and CON rats are almost identical, and that the total calorie intake (from chow plus glucose) is reduced in the DMN rats because the calorie component from chow is profoundly reduced. In response to intraperitoneally injected glucose, VMN rats show a longer depression of food intake than has been reported for mature VMN rats. The CON and DMN rats recovered quicker and reached pre‐injection levels of food intake sooner than the VMN rats. The data indicate that in the weanling VMN rat, as in its mature counterpart, the VMN are involved in long‐term feeding behavior and do respond to the metabolic signal arising from administered glucose. Nevertheless, the principle factor in their preference seems to be taste rather than solely a metabolic signal. The data also show that the DMN are less involved in this sensing and integrating mechanism. In essence, the DMN rat functions quite normally, but its control system is set at a subnormal level.
Effects of specific brain lesions on the thermal responses of rats to d‐amphetamlne
Authors: Yehuda Shlomo 
Published: January 2005

AbstractLesions in either olfactory bulb or in area postrema modify the amphetamine‐induced paradoxical thermoregulatory behavior, although these lesions in no way affect amphetamine‐induced hypothermia. In addition, these lesions lead to complicated patterns of thermoregulatory behavior. These results can be best explained by assuming that lesions in one part of the brain monoamine system might affect levels and turnover of monoamines in remote parts of the brain. Among d‐amphetamine behavioral effects which are known to be mediated by central dopaminergic neurons are hypothermia in animals placed in a cold environment, and paradoxical thermoregulatory behavior (this involves the movement of animals away from the heating source despite hypothermia). This latter effect requires intact alpha norepi‐ nephrine receptors. It seems that neither type of lesion affected dopaminergic neuronal activity in the brain. However, norepinephrine activity in the brain was affected by the area postrema lesion as well as by the olfactory bulb removal.
The effect of α‐melanocyte stimulating hormone (α‐MSH) on the metabolism of blogenlc amines in the rat brain
Authors: Leonard B. E. , Kafoe W. F. , Thody A. J. , Shuster S. 
Published: January 2005

AbstractThe effect of the chronic administration of α‐MSH on the incorporation of tritiated tyrosine into noradrenalin and dopamine and of tritiated tryptophan into serotonin was studied in different regions of the rat brain. α‐MSH increased the incorporation of tritiated tryptophan into serotonin in the cortex and slightly decreased that of tyrosine into the dopamine in the hypothalamus. As the brain concentration of serotonin was unchanged in the animals treated with α‐MSH, it is suggested that some of the changes in behavior, which other investigators have found following the administration of peptides containing the same sequence of amino acids to that found in MSH, could be associated with an increased turnover of cortical serotonin.
A study of 3H‐L‐fucose‐containing glycoproteins of the crude synaptosomal fraction, obtained from rat brain regions at various ages
Authors: Davis Leonard G. , Brunngraber Eric G. , Routtenberg Aryeh 
Published: January 2005

AbstractThe frontal cortex showed a marked elevation of incorporation of H‐L‐fucose into glycoproteins of the crude synaptosomal fraction at 9 days of age. The effect was observed at both 8 and 24 hr after intraperitoneal administration of radioactive fucose. The elevation was absent in the 1, 5, 16, and 25‐day‐old frontal cortices. It was also absent in the hippocampus and cerebellum at all ages studied.Fucose‐labeled glycoproteins of high molecular weight in the crude synaptosomal fraction, as separated by polyacrylamide gels, were preferentially labeled in the hippocampus, frontal cortex, and cerebellum at all ages studied. In general, these glycoproteins became less prominent in the oldest animals studied (25 days). However, the relative amount of these glycoproteins varied with age of the animal, time between administration of isotope and sacrifice, and with the brain areas studied.
Brachium conjunctivum‐red nucleus synaptic system in the baboon
Authors: Huffman R. D. , Davis R. 
Published: January 2005

AbstractElectrophysiological properties of the brachium conjunctivum‐red nucleus (BR‐RN) synaptic system were studied in barbiturate‐anesthetized baboon (Papio). Topographic recordings from the mesencephalon demonstrated that most of the BC‐evoked activity was restricted to an area histologically identified as red nucleus; however, some brachium‐evoked activity was recorded from the surrounding mesencephalic reticular formation. Short latency BC‐evoked activity was also recorded from the pons in the region of nucleus reticularis tegmenti pontis. The majority of the BC fibers were found to conduct at a rat of 44 m/sec; a second group of BC fibers with a slower conduction velocity of 23 m/sec was also observed. Brachium‐evoked responses recorded from magnocellular and parvicellular RN neurons were short latency responses consistent with monosynaptic activation of these RN neurons by the BC fibers. The BC‐RN synaptic system was found to be a very secure synaptic system and could transmit activity at high rates of stimulation with little or no failure. The responsiveness of the BC fibers was found to be similar to that of optic nerve fibers and pyramidal tract fibers, both of which have been characterized as being similar to peripheral A fibers. The responsiveness of the BC‐RN synaptic system began to decrease 5 msec after a single or repetitive transmission and was reduced to about 50% of normal responsiveness at 34 msec. This period of reduced postsynaptic responsiveness was associated with a reduction in presynaptic input to RN and suggest that a disfacilitation at the level of the deep cerebellar nuclei may be in part responsible for the subnormal responsiveness of the BC‐RN synaptic system.
Behavioral evidence showing the predominance of diffuse pain stimuli over discrete stimuli in influencing perception
Authors: Anderson Kenneth V. , Pearl Gary S. , Honeycutt Clegg 
Published: January 2005

AbstractThis experiment was directed toward determining the relative effectiveness of discrete and diffuse pain stimuli in influencing perception and behavior. Shocks to the footpads were use to activate the discrete pain pathways. In the first phase of this experiment, cats were trained to escape from foot shock in a shuttle box. Current applied to the feet was varied in ascending and descending sequences for each animal according to the psychophysical method of limits and each animal was trained until stable thresholds for escape responding were achieved. In the second phase of the experiment, the effect on behavior of simultaneous activation of both the discrete and diffuse pain systems was assessed. The principal finding in this experiment was that escape responding that was well established when foot shock was presented alone was routinely abolished on trials when tooth shock and foot shock were presented together. These results were interpreted as indicating that the diffuse pain system was prepotent in influencing behavior when both the discrete and diffuse pain systems were activated simultaneously.