bluuebunny/crossref_metadata_2025_split huggingface dataset:
Isoniazid induced seizures and cerebral cortical and cerebellar energy metabolism
Authors: McCandless D. W. , Abel M. S. , Schwartzenburg F. C. 
Published: January 2005

AbstractIsoniazid is a useful chemical convulsant in that metabolic events associated with the preseizure state can be easily examined. In the present study, net levels of glucose, glycogen, ATP, and phosphocreatine were measured using enzymatic techniques in control mice, and in those injected with isoniazid. Results from this study showed a differential effect of isoniazid on cells from the cerebral cortex and the cerebellum. In the preseizure stage, the high energy phosphates ATP and phosphocreatine were decreased in layer 1 and the pyramidal cell layer of the cerebral parietal cortex, but were unchanged in the cerebellum. At the onset of seizures, metabolites were decreased not only in cortical layers, but in the molecular layer and Purkinje cell rich layer of the cerebellum as well. The somewhat delayed response of the cerebellum emphasizes the differential nature of metabolism in various brain regions. Such a delay in cerebellar energy response to perturbation may be conducive to the seizure state. In another series of mice, either sodium valproate or clonazepam was administered prior to isoniazid, and metabolite studies repeated. Results showed that at a time when each anticonvulsant acted to eliminate overt seizure activity, the reduction in ATP and phosphocreatine was not as great as it was in seizing mice treated with isoniazid alone.
Effects of L‐glutamate and GABA on the response of expiratory neurons to mechanical loads
Authors: Toleikis J. R. , Frazier Donald T. 
Published: January 2005

AbstractExpiratory neurons in the area of the nucleus retroambigualis were studied in anesthetized cats to determine their responsiveness to the iontophoretic application of the putative neurotransmiters, glutamate and gamma‐aminobutyric acid (GABA). Previous studies with glutamate and GABA revealed that these two substances were very effective in modulating the spontaneous activity of phasic medullary respiratory neurons. Mechanical loading of expiration, both resistive and elastic, was employed to test whether the presence of these transmitter substances altered the sensitivity of the expiratory cell to its volume related vagal input.Expiratory unit activity analysis included: spikes/burst, burst duration, and average firing rate. Addition of mechanical loads on expiration caused consistent increases in all parameters monitored. Iontophoretically applied glutamate (x̄ = 65 nA) resulted in modest increases in all parameters. When mechanical loads were applied in the presence of a sustained level of glutamate the effects were additive. The general shape of the firing profile observed with loading remained essentially unchanged. Application of GABA (x̄ = 46 nA) resulted in a significant decrease in the parameters monitored. However, as long as phasic activity remained, loads applied in the presence of GABA produced approximately the same absolute change as they did during control. Some cells exposed to high concentrations of GABA lost their phasic activity.This study suggests that either the synaptically activated receptors are not affected by glutamate or that these particular sites are not accessible via iontophoretic application. GABA depressed the activity of the cells in a graded fashion, but in modest concentrations did not interfere with the overall effectiveness of the vagally mediated input.
Lateral geniculate cells responses following blockade of the visual cortex in rats: A comparison with rabbits
Authors: Molotchnikoff S. , Tremblay F. , Baron G. 
Published: January 2005

AbstractThe functions of the visual cortex (VC) were interrupted in anesthetized and paralyzed hooded rats with KCl (3M Baker) applied topically and single unit recordings were performed on lateral geniculate cells. Responses of geniculate cells to diffuse 1 second flashes were tested prior to and following cortical inactivation. The results indicated: (1) a differential decline of “on” and “off” responses; (2) a shift of excitatory and inhibitory periods in some units; (3) a modification of spontaneous firing; and (4) the corticofugal influence in rats is comparable to rabbits, suggesting a similar organization in both species.
Bilateral secretory responses of the adrenal medulla during stimulation of hypothalamic or mesencephalic sites
Authors: Francke Paul F. , Culberson James L. , Carmichael Stephen W. , Robinson Robert L. 
Published: January 2005

AbstractBilateral secretion of epinephrine and/or norepinephrine from adrenal medullae occurred in 76% of cats studied following unilateral electrical stimulation of sites in the hypothalamus or rostral mesencephalon. Responses were generally greater on the ipsilateral side. In most experiments, epinephrine alone or both epinephrine and norepinephrine outputs were increased. In only two experiments norepinephrine output was increased. Stimulation of most hypothalamic sites that evoked bilateral secretion was accompanied by an increase in blood pressure. Stimulation of effective sites in the mesencephalon was not generally accompanied by blood pressure changes.
Pattern of acetylcholine receptor activity during regeneration of free muscle transplants of rats
Authors: Mong Franz S. F. , Farach Mary C. , Martinez‐Carrion Marino 
Published: January 2005

AbstractAcetylcholine receptor (AChR) activities were followed in regenerating muscle grafts of rats. The effects of prior nerve crush or treatment with Marcaine on α‐Bungarotoxin binding in graft muscle extracts were compared to nontreated controls. All treatment groups displayed a similar but characteristic pattern in which minor differences in the time course and absolute levels of AChR activities were observed. These results are interpreted in terms of possible alterations in AChR levels brought about by the changes in the degree of graft innervation.
Automatic control of potential and agonist‐induced current across the endplate membrane by drug electrophoresis
Authors: del Castillo J. , Specht P. , Auerbach A. 
Published: January 2005

AbstractTwo techniques are described that are designed to elicit long and constant postsynaptic depolarizations or agonist‐induced currents by the electrophoretic application of agonists to endplate membranes. In the first technique, which can be described as a “pharmacologic voltage clamp,” the current flowing through the agonist pipette is controlled by the potential across the endplate membrane. Sustained depolarizations of constant amplitude can be obtained in this manner, while the agonist current needed to produce and maintain the response is recorded. The second technique uses a signal proportional to the current flowing across a voltage‐clamped endplate membrane to control the delivery of agonist. This allows control of the intensity of the agonist‐induced current. The possible application of these techniques in studying receptor desensitization and obtaining samples of post‐synaptic current noise for spectral analysis is discussed.
Intracellular volume of osmotically regulated C‐6 glioma cells
Authors: Chan Pak Hoo , Kerlan Randi , Fishman Robert A. 
Published: January 2005

AbstractThe intracellular volume of neoplastic brain cells was investigated with regard to the effects of hypo‐osmolality and hyperosmolality utilizing double isotopic labeling with 3–0‐methyl‐D‐glucose or tritiated water to measure the total volume of the pellet and inulin or polyethyleneglycol to measure the extracellular volume of the pellet. The cellular pellets were rapidly separated from the incubation medium by centrifugation after addition of an oil mixture. After 60 minutes incubation in Hanks balanced salt medium, the intracellular volume was 7.50 ± 0.64, 8.48 ± 0.19, and 2.97 ± 0.18 ml H2O per 106 packed cells for C‐6 glioma cells, N18TG‐2 neuroblastoma cells, and NG108‐15 neuroblastoma X glioma hybrid cells, respectively. The extracellular trapped space of these cultured cells was about one third of the intracellular volume. The intracellular volume of C‐6 glioma cells was increased in hypotonic environment, whereas it was decreased with hyperosmolality. Both intracellular sodium and potassium were increased with increased osmolality of the incubation media. These data indicate iso‐osmotic regulation by tumor cells, i.e., there is a good correlation between the intracellular volume, intracellular cations and lactate levels of C‐6 glioma cells under various osmotic conditions.
Nerve growth factor, laminin, and fibronectin promote neurite growth in human fetal sensory ganglia cultures
Authors: Baron‐Van Evercooren Anne , Kleinman Hynda K. , Ohno Shinichi , Marangos Paul , Schwartz Joan P. , Dubois‐Dalcq Monique E. 
Published: January 2005

AbstractThe effect of mouse nerve growth factor (NGF) on cultured human fetal sensory neurons was assayed by measuring neurite length, density and rate of growth. Addition of NGF increased adhesion of dissociated sensory neurons cultured on collagen coated surfaces. Almost all neurons of 9 to 10 week old fetuses are postmitotic, contain neuron‐specific enolase, (an enzyme linked to differentiation), and require NGF for optimal neurite growth. Sensory ganglia re‐explanted on collagen showed maximal neurite length and density when treated with 1 ng/ml of NGF. Neurite density was reduced considerably in the absence of mouse NGF and was almost abolished by addition of antimouse NGF antibodies. Surfaces coated with the matrix glycoproteins laminin or fibronectin further stimulated neurite growth of ganglia in the presence of NGF. Increasing amounts of matrix proteins could partly compensate for the absence of mouse NGF or the inhibition of NGF activity by antibodies. Stimulation of neurite growth by matrix proteins was time‐dependent, and neurites showed maximum length at 10 days (2 to 3 mm). Neurite growth was more pronounced with laminin than with fibronectin and collagen, and antibodies to laminin suppressed all neurite growth. In the presence of a constant amount of NGF, mean neurite growth reached 26 μm/hr (at 1 day), and was 2.1 and 1.7 times faster on laminin and fibronectin (respectively) than on collagen. Thus, laminin, and to a lesser degree fibronectin, may enhance neurite growth of human sensory neurons in synergy with NGF.
Increase of a nerve growth factor‐like protein in the cerebellum of PCD mutant mice
Authors: Schwartz Joan P. , Ghetti Bernardino , Truex Lewis , Schmidt Michael J. 
Published: January 2005

AbstractSeveral areas of mouse brain (cerebellum, brain stem, and hemispheres) contain levels of nerve growth factor (NGF) detectable by radioimmunoassay. However, this immunoactive NGF is not biologically active in the chick embryo sensory ganglia bioassay. Cerebellum from pcd mice, in which neuronal degeneration elicits a glial response, contains increased amounts of NGF immunoactivity. These results suggest that CNS glia may produce a NGF‐like protein for CNS neurons.
Insulin and somatemedin MSA promote nerve growth factor‐independent neurite formation by cultured chick dorsal root ganglionic sensory neurons
Authors: Bothwell Mark 
Published: January 2005

AbstractSensory neurons isolated from 8‐day chick embryo dorsal root ganglia are shown to be capable of surviving in tissue culture and extending neurites in the absence of nerve growth factor. Survival and formation of neurites by cells cultured in medium supplemented with 2% fetal calf serum is stimulated by insulin, proinsulin or somatemedin MSA. MSA is effective at much lower concentrations (50 ng/ml) than insulin or proinsulin and is suggested to be a physiological regulator of sensory neuronal development. It is demonstrated that at least part of the neuronal population is responsive to both nerve growth factor and insulin homologs.
Neurite outgrowth from cerebral cortical neurons is promoted by medium conditioned over heart cells
Authors: Kligman Douglas 
Published: January 2005

AbstractSeven day chick embryo cerebral cortical neurons cultured at low density (10,000 cells/16 mm well) in serum‐free, defined medium in polylysine‐coated wells fail to extend neurites and assume a flattened phase‐dark morphology. Addition of serumfree, defined medium conditioned over chick embryo heart cells promotes neurite outgrowth and rounding of the cell body (which becomes phase bright). A sensitive bioassay, based on counting the number of phase‐bright neurons with processes at least equal to one cell body diameter after 20 hours in culture, was used to titrate neurite‐promoting activity in heart conditioned medium. This activity is completely destroyed by exposure to trypsin. As little as 2 μg/ml total conditioned medium protein elicits a half‐maximal response in this bioassay.
Nerve growth factor‐induced stimulation of α‐aminoisobutyric acid uptake in PC12 cells: Relationship to plasma membrane receptor occupancy
Authors: Kedes Dean H. , Gunning Peter W. , Shooter Eric M. 
Published: January 2005

AbstractNerve growth factor (NGF) stimulates the uptake rate of the nonmetabolized amino acid α‐aminoisobutyric acid (AIB) in the clonal PC12 pheochromocytoma cell line by 40–70%. This effect reaches a maximum after a 1‐hour incubation with the hormone and then drops over 50%, reaching a minimum after 4 hours of NGF administration. Longer exposure to the hormone leads to a gradual rise in stimulation, and by 24 hours, the cells regain about 80% of the original 1‐hour rate. Results of NGF‐binding studies indicate that stimulation of AIB uptake follows closely behind the amount of NGF bound to the low‐affinity NGF receptors. Dose‐response experiments indicate that full stimulation occurs biphasically. Within the NGF concentration range of 0.1 ng/ml to 1 ng/ml, the AIB uptake rate is 30% of the maximum 1‐hour response. At 2.5 ng/ml NGF, the stimulation jumps to about 75% maximal response while 100% response is reached between 5 ng/ml and 50 ng/ml NGF. We suggest that the two states of the NGF plasma membrane receptor on PC12 cells may both be involved in mediating NGF stimulation of AIB uptake.
Effect of thiamine deficiency and undernutrition on the lipid composition of rat spinal cord at 21 days of age
Authors: Reddy T. Sanjeeva , Ramakrishnan C. V. 
Published: January 2005

AbstractMaternal thiamine deficiency and undernutrition are found to cause significant deficits in body and spinal cord weights of the offspring at 21 days of age. The concentration of different lipids is found to be decreased significantly in both experimental groups as compared to normal controls. However, these deficits do not seem to differ between the undernourished and the thiamine‐deficient groups. The results suggest a general effect of growth retardation rather than thiamine deficiency per se on the lipid composition of spinal cord.
Effect of undernutrition on some enzymes of purine metabolism in different regions of developing rat brain
Authors: Vanella A. , Barcellona M. L. , Avitabile M. , Avola R. , Ragusa N. , Serra I. , Giuffrida A. M. 
Published: January 2005

AbstractThe effect of undemutrition on the activity of some enzymes involved in purine metabolism, ie, adenosine aminohydrolase, adenylate aminohydrolase, and inosine phosphorylase in cerebral hemispheres, cerebellum, and brain stem of rats at different days of postnatal development was studied. Adenosine aminohydrolase, adenylate aminohydrolase, and inosine phosphorylase were assayed by radiochemical methods which involve the measurement of the radioactive products formed, ie, inosine, IMP, and hypoxanthine, respectively. The results obtained indicate that undemutrition affects the activity of the enzymes which control the concentration of purine nucleotides to a different degree in the three brain regions examined.
The principal projection pathway between the olfactory bulb and the prepyriform cortex in the cat
Authors: Willey T. J. , Maeda G. , Schultz R. L. , Seibly W. S. , Horowitz J. M. 
Published: January 2005

AbstractThe anatomy and neuroelectric properties of the lateral olfactory tract (LOT) were investigated in the cat. Electron micrographs were obtained from sampled areas across the rostro‐caudal projection of the pathway. Fiber diameters were estimated and axon spectra were obtained from three regions corresponding to penduncle, mid‐LOT, and caudal‐LOT. The mean inside diameter for all measured axons was 1.13 ± 0.53 μm. The greatest number was found in the peduncle (approximately 600,000 axons). Mid‐LOT and caudal‐LOT each contained approximately 250,000 axons. Unmyelinated processes were estimated to be more numerous than the myelinated axons. Synaptic structures were also observed in the LOT. Crosssectional area measurements of the LOT were obtained from tissue repared for light microscopy. The area decreased from about 0.3 to 0.2 mm2 across the projection from olfactory bulb to cortex. The anatomical data were used to predict the conduction properties of transmission over the LOT. The olfactory bulb mitral cells were stimulated electrically and conduction velocity and temporal dispersion were evaluated in the tract. The strength‐duration and stimulus‐response curves and the potential profile during stimulation were also obtained. The time constant for LOT axons was 0.3 msec. The stimulus‐response curve was sigmoidal in shape for both presynaptic and postsynaptic responses. The relationship between input (the action potentials) and output (cortical postsynaptic potentials) was linear up to 90 times threshold. Action potentials were conducted at 20 m/sec across the pathway over the peduncle and decreased to about 10 m/sec in caudal aspects. The potential profile for action potentials decayed exponentially into the depths of the cortex whereas the synaptic potential was a surface negative dipole field. The axon spectra were convolved with the electrophysiological properties of the LOT Yto mathematically reconstruct action potentials. The empirically derived monoand biphasic curves fitted reasonably well with experimentally derived data under various stimulus conditions.
Morphological changes in neuromuscular junctions during exercise
Authors: Palacios‐Prü Ernesto , Mendoza R. V. , Palacios L. , Colasante C. 
Published: January 2005

AbstractLong lasting exercise produces several morphological changes in teleostean neuromuscular junctions (NJs), consisting of progressive synaptic vesicles (SVs) depletion and lamellar branching of the nerve endings. Exercised fishes kept swimming during 1 hr against a 3.51/min flow of oxygenated water in spite of the fact that the number of SVs was reduced in about 70% after 10 min of exercise. This observation indicates that the SVs formation fails to restore their original number and consequently, under such circumstances, the transmitter release may occur by a different mechanism.
Cross‐reactivities of monoclonal antibodies between select leech neuronal and epithelial tissues
Authors: Hogg N. , Flaster M. , Zipser Birgit 
Published: January 2005

AbstractThree monoclonal antibodies, originally studied because of their neuron‐specific staining in the leech central nervous system, are characterized further here, both immunocytochemically and biochemically, with Western blot staining using the central nervous system and peripheral tissues. The three antibodies react both with neurons and select epithelial tissue in the central nervous system, gut, and penis. Antibody Lan3‐8 reacts with neurons in the nerve cord and gut but with epithelial cells in the penis; it binds to a 65K molecule in all three tissues. Lan3‐2 and Laz2‐369 are considered as a related pair because in the central nervous system the former stains all (four) and the latter generally only half (two) of the neurons in a standard midbody ganglion responding to nociceptive stimulation. In the gut, both antibodies label patches of epithelial cells and Laz2‐369 stains a previously unknown type of gut neuron. While a given antibody stains different bands in gut and central nervous system immunoblots, comparing the bands of both antibodies for the same tissue extract makes it apparent that there are similarities in the molecular species that both antibodies recognize.For each monoclonal antibody, the histologically identified tissue antigens need to be correlated with proteins identified on Western blots. Of particular interest are the broad 130K bands to which Lan3‐2 and Laz2‐369 bind. The question is raised whether the molecular species in these bands represent a family of proteins that serve a specific nociceptive cell function.
Procedure for isolation of neuron‐ and astrocyte‐enriched fractions from chick brain of different ages
Authors: Rani B. Usha , Singh N. Indrapal , Ray A. , Rao K. Subba 
Published: January 2005

AbstractA method for the isolation of ncurons and astrocytes from chick brain of different ages is described. In brief, the procedure involves incubation of the gray matter with trypsin, passage of the tissue successively through nylon/stainless steel screens of decreasing pore size, and further separation and purification of cell‐enriched fractions by centrifugation on Ficoll discontinuous gradient. Phase‐contrast microscopy revealed intact morphology of the cells. The cells were viable by trypan blue exclusion test.
Substrate specificity and developmental aspects of a presynaptic gaba receptor regulating glutamate release in the rat cerebellum
Authors: Aloisi F. , Gallo V. , Levi G. 
Published: January 2005

AbstractIn order to better characterize the presynaptic GABA receptors regulating glutamate release in the cerebellum [Levi and Gallo, 1981], a number of GABA agonists and GABA transport inhibitors were tested for their ability to potentiate the depolarization‐induced release of the glutamate analog D‐[3H]aspartate from superfused cerebellar synaptosomes. Of all the compounds tested, only those which are known to interact specifically with GABA receptors were effective when tested on synaptosomal preparations. The order of effectiveness found was the following: muscimol ≃ 3‐APS≥P4S > isoguvacine >THIP. GABA uptake inhibitors were unable to enhance D‐[3H]aspartate evoked release from synaptosomes, but were effective when tested in cerebellar slices; in the latter case, the activation of the GABA receptors may be achieved indirectly, through an increase of the extracellular GABA concentrations. The substrate specificity of the presynaptic GABA receptors regulating cerebellar acidic amino acid release appears to be similar to that reported for GABA receptors in radioligand binding studies and for GABA autoreceptors. Studies on synaptosomes from immature cerebella suggested that the presence of the potentiating effect on the acidic amino acid release by GABA agonists is correlated with the development of the parallel fiber terminals, which are believed to be the main site from which glutamate is released in the adult cerebellum.