bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evalutation of the pharmacological similarities between phenlpopanolamine andamphetamine: Effects on schedule‐controlled behavior
Authors: Wagner George C. , Jarvis Michael F. 
Published: January 2005

AbstractIn an effort to determine the degree to which the repeated administration of phenylp0ropanolamine (PPA) results in the development o tolerance to its disruptive effects on operant responding as wellas cross‐tolerance to the effets of autely administered amphetamine, water‐deprived rats were first trained on a fixed‐ratio 5 (FR‐5) schedule for water presentation. Dose‐response curves for the effects of PPA and amphetamine (administered IP, 15 min presession) were then determined (ED5 = 35.0 and 2.6 mg/kg, respectively) followed by the chronic administration of 40.0 mg/kg PPA (administered IP, 15 min prior to each session). When responding returned to pre hronic rates, the dose‐response curves wee redetermined for both PPA (ED50=220 mg/kg) and amphetamine (ED50=48mg/kg). In a second set of rats, trained under similar conditions, it was observed that pretreatment with alpha‐methyltyrosine (AMT, 100 mg/kg IP, 2 h presession) antagonized the disruptive effets of both PPA and amphetamine, whereas pretreatment with reserpine (0.31 mg/kg, IP, 12 h presession) antagonized the disruptive effects of PPA, but exacerbated the disruptive effects to amphetamine. In a separate experiment, the repeated administration of PPA 1 mg/kg IP resulted in no long‐lasting depetions of atstriatal dopamine, serotonin, or 3,4‐dinhydroxphenylacetic acid (DOPAC) concentrations. These observations indicate that PPA and amphetamine share a similar mechanism of action to the degree that cross‐tolerance develops, but which isnonetheless dissociable with respect to their differential sensitivity to antagonists and their neurotoxic efficacy.
Thyrotropin‐Releasing hormone has profound presynaptic action on cultured spinal cord neurons
Authors: Behbehani Michael M. , Pun R. Y. K. , Means Eugene D. , Anderson Douglas K. 
Published: January 2005

AbstractThyrotropin‐releasing hormone (TRH) receptors are widely distributed throughout the nervous systems. In particular, both the dorsal and the ventral horn (VH) neurons contain a rich distribution of TRH receptors, and TRH application to these sites has profound physiological effects. Currently the mechanism of action of TRH is not known. We examined the effect of TRH on ventral horn neurons using intracellular and patch‐clamp techniques. Our results indicate that TRH application profoundly increases the firing rate of VH cells by decreasing membrane conductance. More importantly, TRH causes a significant increase in frequency and amplitude of postsnaptic potentials. Under voltage‐clamp condition, TRH reduces holding current and causes a significant increase in the rate of occurrence and the amplitude of excitatory postsynaptic currents (EPSCS), an effect that lasts for more than 5 minutes. This effect of TRH is not observed in of the EPSCS when it is applied to a region of the cell that is sparsely innervated. These results provide strong evidence that presynaptic mechanisms have a significant role in the excitatory effect of TRH on the VH neurons. Because there is evidence that trophic factors are released from presynaptic terminals, by increasing synaptic activity, TRH can have a trophic influence on the spinal cord neurons. In addition, because there are a significant number of TRH containing neurons within the spinal cord, it is likely that TRH has a major role in information processing within the spinal cord.
Positron emission tomography (PET) studies of dopaminergic/cholinergic interaction in the baboon brain
Authors: Dewry Stephen L. , Brodie Jonathan D. , Fowler Joanna S. , MacGregor Robert R. , Schlyer David J. , King Payton T. , Alexoff David L. , Volkow Nora D. , Shiue Chyng‐Y. , Wolf Alfred P. , Bendriem Bernard 
Published: January 2005

AbstractInteractions between the dopaminergic D2 recceptor system and the muscarinic cholinergic system in the corpus striatum of adult female baboons (Papio anubis) were examined using positron emission tomography (PET) combined with [18F]N‐methylspiroperidol ([18]NMSP) (to probe D2 receptor availability) and [N‐11C‐methyl]benztropine (to probe muscarinic cholinergic receptor availability). Pretreatment with benztropine, a long‐lasting anticholinergic drug, bilaterally reduced the incorporation of radioactivity in the corpus striatum but did not alter that observed in the cerebellum or the rate of metabolism of [18F]NMSP in plasma. Pretreatment with unlabelled NMSP, a potent dopaminergic antagonist, reduced the incorporation of [N‐11C‐methyl]benztropine in all brain regions, with the greatest effect being in the corpus striatum < cortex < thalamus < cerebellum, but did not alter the rate of metabolism of the labelled benztropine in the plasma. These reduction in the incorporation of either [18F]NMSP or [N‐11C‐methyl]benztropine exceeded the normal variation in tracer incorporation in repeated studies in the same animal. This study demonstrates that PET can be used as a tool for investigating interactions between neurochemically different yet functionally linked neurotransmitters systems in vivo and provides insight into the consequences of multiple pharmocologic administration.
Differential effects of intracerebroventiricular colchicine administration on the expression of mrnas for neuropeptides and neurotransmitter enzymes, with specila emphasis on galanin: An in situ Hybridization Study
Authors: Cortės Roser , Ceccatelli Sandra , Schalling Martin , Höukfelt Tomas 
Published: January 2005

AbstractThe axonal transport blocker clochicine has been extensively used in immunohistochemical studies to induce accumulation of neuroactive compounds, especially neuropeptides, in neuronal somata and thus improve their visualization. To assess whether colchicine might, in addition, ifluence the synthesis of such compounds, we have now used in situ hybridization to examine the level of mRNAs encoding for several neuropeptides (galanin[GAL], cholecystokinn [CCK], somatostatin [sOM], neuropeptide Y[NPY]) and neurotransmitter‐synthesizing enzymes (chloine acetyltransferase [ChAT], tyrosine hydroxylase [TH], amino acid decarboxylase [AADC], and glutamic acid decarboxylase [GAD]) after intraventricular administration of the drug. The results show that colchicine differntially modifies the level of several mRNA species in different brain areas. Thus GAL mRNA levels increase in virtually all regions examined, including the basal forebrain, hypothalamus, dorsal raphe nucleus, locus coeruleus to be induced in the ipsilateral hemisphere in region such as the cortex, hippocampus, striatum, lateral septum, and some nuclei of the thalamus as well as within white matter, where it cannot be detected in control animals. Although GAL mRAN in the vast majority of cases is neuronal, some findigs indicate a possible glial localization. In parallel, clochicine depletes chAT mRNA and increase GAD mRNA in the basal forbrain and striatum and decreases AADC mRNA in the dorsal raphe nucleus and locus coeruleus. In the latter nucleus, NPY and TH mRNA level are increased by clochcine. In contrast, TH mRNA and also CCK mRNA level decrease in the substantia nigra. In the cortex, hippocampus, and thalamus ipsilateral to colchicine injection CCK mRNA level are markedly decrease, whereas sOM mRNA level decreas and NPY mRNA increase in the hippocampus, but unchanged in the cortex. The result are discussed with reference to the possible artifacts that the use of colchicine might induce in immunohistochemical mapping studies and in relation to possible neurotoxic action of colchicine, in some cases perhaps related to impaired retrograde transport of growth factor(s).
Effect of thiol group modification on ion flux and ligand binding properties of the GABAA‐benzodiazepine receptor chloride channel complex
Authors: Allan A. M. , Baier L. D. 
Published: January 2005

AbstractAgents that modify thiol groups have been shown to alter ligand binding at a variety of receptor sites. In addition, alkylation of sulfhydryls has been shown to block ion channel conductance. We studied the effects of thiol reagents on γ‐aminobutyric acid (GABA)‐activated chloride flux (36Cl−) and [3H]‐diazepam binding in mouse brain membrane preparation (microsacs). Incubation of microsacs in the presence of: mercuric chloride (HgC12), p‐chloromercuriphenylsulfonic acid (pCMBS), hydroxymercuribenzoate (HMB), n‐ethylmaleimide (NEM), or iodoacetic acid (IAA) attenuated GABA‐stimulated Cl− uptake. The thiol reagents reduced both maximal stimulation and the potency of GABA to induce Cl− uptake. Thiol reagent treatment decreased the affinity of high‐affinity [3H]‐muscimol equilibrium binding. Supernatant prepared from microsacs treated with pCMBS stimulated Cl− uptake in the absence of GABA agonist in microsacs unexposed to thiol reagents. The supernatant taken from pCMBS‐treated microsacs also stimulated [3H]‐diazepam binding. This effect was blocked by the addition of the GABA receptor antagonist bicuculline. The concentration of endogenous GABA in supernatant from pCMBS‐treated microsacs was sixfold greater than that in supernatant from control microsacs. This increase in levels of endogenous GABA by thiol reagents was due to both an increase in GABA release and a decrease in high‐affinity GABA uptake.
Presynaptic mechanism for heterosynaptic, posttetanic depression in area CA1 of rat hippocampus
Authors: Grover Lawrence M. , Teyler Timothy J. 
Published: January 2005

AbstractConditioning stimulation applied to afferent fibers in stratum radiatum or stratum oriens of hippocampal area CA1 produced heterosynaptic, posttetanic depression (PTD) of excitatory postsynaptic potentials (EPSPs). PTD amounted to a 60–80% reduction of EPSPs and recovered over a 5 min period. Conditioning stimulation also induced a posttetanic hyperpolarization (PTH) averaging 4 mV and decaying over a 1–1.5 min period. PTH was accompanied by a large reduction in input resistance. We sought to determine the pre‐ or postsynaptic locus of heterosynaptic PTD. Our results suggest that PTD reflects a presynaptic mechanism: (1) PTD was observed for both N‐methyl‐Daspartate (NMDA) and non‐NMDA receptor mediated EPSPs; (2) Direct depolarization of pyramidal cells, substituted for the synaptic depolarization induced by conditioning stimulation, did not elicit PTD; (3) PTD and PTH were differentially affected by pharmacological and postsynaptic manipulations; (4) Conditioning stimulation depressed responses to pressure applied glutamate, but the magnitude and duration were too small to account for PTD. Since afferent fiber volleys were not depressed following conditioning stimulation, while field EPSPs were, we conclude that conditioning stimulation suppresses synaptic release of glutamate. © 1993 Wiley‐Liss. Inc.
Immunochemical localization of calcium/calmodulin‐dependent protein kinase I
Authors: Picciotto Marina R. , Zoli Michele , Bertuzzi Gloria , Nairn Angus C. 
Published: January 2005

AbstractCa2+/calmodulin‐dependent protein kinase I (CaM kinase I) was originally identified in rat brain based on its ability to phosphorylate site 1 of synapsin I. Recently a cDNA for the rat brain enzyme has been cloned and the primary structure elucidated [Picciotto et al. (1993), J. Biol. Chem., 268:26512–26521]. The rat cDNA encoded a protein of 374 amino acids with a calculated Mr of 41,636. Antibodies have now been raised against the recombinant kinase expressed in E. coli as a glutathione‐S‐transferase fusion protein. Immunoblot analysis of rat cortex lysates revealed two major immunoreactive bands of ∼Mr 38,000 and 42,000. Minor immunoreactive species of slightly lower Mr were also detected. Two distinct CaM kinase I activities were partially purified from rat brain and shown to correspond to the two major immunoreactive species. A variety of immunoreactive species of Mr 35–43,000 were detected in “brain” tissue from cow, zebra finch, goldfish, Xenopus, lamprey, and Drosophila. In rat brain, immunocytochemistry revealed strong staining in cortex, hippocampus, amygdala, hypothalamus, brain stem, and choroid plexus. The labelling was mainly observed in neuropil but clusters of intensely labelled neuronal cell bodies were also detected all along the neuraxis. Neuronal nuclei and glial cells did not appear to be stained. Subcellular fractionation studies confirmed the cytosolic localization of the kinase in the brain. In various rat non‐neuronal tissues and in a number of cell lines, immunoreactive species of ∼Mr 38,000 and ∼42,000 were detected at lower levels than that detected in brain. The Mr 38,000 and 42,000 species were also found in different ratios and at different levels in the non‐neuronal tissues. These results support a role for CaM kinase I in the regulation of multiple neuronal processes. Furthermore, the widespread cell and tissue distribution suggests that CaM kinase I may function as a ubiquitous multi‐functional protein kinase. Finally, the multiple immunoreactive species may represent isoforms of CaM kinase I. © 1995 Wiley‐Liss, Inc.
Effect of calpain on the composition and structure of postsynaptic densities
Authors: Dosemeci A. , Reese T. S. 
Published: January 2005

AbstractEndogenous calcium‐activated proteases, the calpains, are thought to play a role in the regulation of postsynaptic function. Here we characterize some biochemical and morphological effects of calpain on isolated postsynaptic densities (PSDs). When a PSD preparation from rat forebrain was treated with exogenous calpain, many proteins, including spectrin, tubulin and the α‐subunit of calcium calmodulin‐dependent protein kinase (α‐CaM kinase), were proteolyzed at varying rates, while another major protein, actin, remained intact. The selectivity of calpain action became more apparent in experiments designed to achieve limited proteolysis by using a lower calpain‐to‐protein ratio; it was possible to obtain extensive breakdown of spectrin with no decrease in the levels of either tubulin, α‐CaM kinase, or actin. Electron microscopy of freeze‐substituted preparations showed that limited calpain action caused a partial unraveling of the PSD, in which the characteristic central dense lamina became wider and less dense. We interpret these changes as due to calpain‐mediated breakdown of cross‐bridging elements, leading to a partial unraveling of the central PSD lamina. Opening up of the PSD structure following limited calpain action could facilitate exposure of previously occluded functional sites within the PSD and contribute to the modification of the synaptic function. © 1995 Wiley‐Liss, Inc.This article is a US Government work and, as such, is in the public domain in the United States of America
.
Antibodies to calcium channels from ALS patients passively transferred to mice selectively increase intracellular calcium and induce ultrastructural changes in motoneurons
Authors: Engelhardt József I. , Siklós László , Kőműves Lászloó , Smith R. Glenn , Appel Stanley H. 
Published: January 2005

AbstractAntibodies to Ca channels in ALS patients IgG can be demonstrated to enhance Ca current and cause cell injury and death in a motoneuron cell line in vitro. To determine whether these antibodies can alter neuronal calcium homeostasis in vivo IgG fractions from six ALS patients were injected intraperitoneally into mice, and neurons assayed by ultrastructural techniques for calcium content. After 24 h, all six ALS IgG (40 mg/animal) increased vesicle number in spinal motoneuron axon terminals, and in boutons synapsing on spinal motoneurons. Using the oxalate‐pyroantimonate technique for calcium precipitation, these antibodies produced dose‐dependent calcium increases either in axon terminal synaptic vesicles and mitochondria, or in rough endoplasmic reticulum, mitochondria, and Golgi complex of spinal motoneuron and frontal cortex pyramidal cells. ALS IgG was itself internalized and also induced neurofilament H phosphorylation. The observed changes in ultrastructure and calcium compartmentation were restricted to motoneurons; normal and disease control IgG, which did not possess antibodies enhancing calcium entry, did not exert similar effects. These data demonstrate that ALS IgG containing Ca‐channel antibodies can alter calcium homeostasis of motoneurons in vivo. © 1995 Wiley‐Liss, Inc.
Über neue Methoden in der Alkali‐ und Acidimetrie, Oxydimetrie und Fällungsmaßanalyse. Hydrolytische Fällungsmaßanalyse und Mercurimetrie
Authors: Jellinek Karl , Keebs Paul 
Published: January 2005

AbstractDie Auffindung von 4 neuen anorganischen Indikatoren für die Acidimetrie, und zwar: Indikatoren, die den Umschlag durch Trübung anzeigen. a) Pb‐Salz für alle Säuren und Basen außer H2SO4. b) Cu‐Salz fur alle Säuren und Ammoniak. c) Ag‐Salz für alle Säuren außer HCl, HJ, HBr und alle Basen außer Ammoniak.
Über die Oxydation von Hydroxylamin
Authors: Kurtenacker Albin , Neusser Robert 
Published: January 2005

AbstractOxydiert man Hydroxylamin mit überschüssigem Permanganat, so hängt der Permanganatverbrauch sehr von der Azidität bzw. Alkalität der Lösung ab und erreicht in schwach alkalischer Lösung ein sehr scharf ausgeprägtes Minimum.
Über die Karbonate der seltenen Erden. II. Die thermische Dissoziation der Ceritcarbonate
Authors: Preiss Josff , Rainer Norbert 
Published: January 2005

AbstractDie thermische Dissoziation, die durch Erhitzungs‐ und Temperatur‐Gewichtskurven verfolgt wurde, zeigte, unterstützt durch die Ergebnisse der Hydrolyse, daß den neutralen Ceritcarbonaten die Strukturformel zukommt, deren 3 CO2 verschieden starke Bindung haben, die in allen Fallen eine Stufendissoziation bedingt.
Beiträge zur systematischen Indikatorenkunde. 7. Mitteilung. Die Konstruktion von Titrationskurven
Authors: Thirl A. 
Published: January 2005

Abstract1. Mit Hilfe des „logarithmischen Verfahrens”︁, bei dem der Zustand einer Mischung von Säuren und Basen als Funktion der Säurestufe der Lösung entwickelt wird, läßt sich eine wesentliche Vereinfachung der Berechnung erzielen.
Beiträge zur Theorie der elektrolytischen Ionen. Nr. 29. Über eine Verbesserte Methode der Leitfähigkeitsmessung durch Einführung des Röhrenverstärkers und ihre Begründung
Authors: Lorenz Richard , Klauer Hans 
Published: January 2005

AbstractEs wird der Röhrenverstärker in die Methode von KOHLRAUSCH zur Bestimmung des Leitvermögens von Elektrolyten eingeführt, seine Wirkungsweise und sein Einfluß innerhalb dieser Methode werden untersucht.
II. Die Beziehung zwischen der Rührgeschwindigkeit und der Reaktionsgeschwindigkeit in heterogenen Systemen
Authors: Klein A. 
Published: January 2005

AbstractDie Reaktionsgeschwindigkeit in heterogenen Systemen ist als Summe zweier Größen aufzufassen, deren eine für die gegebene Reaktion konstant und die andere der Rührgeschwindigkeit proportional ist. Der Proportionalitätsfaktor ist von der Rührvorrichtung abhängig und zwar wird er schon durch geringe Änderungen dieser deutlich beeinflußt.
Experimentelle Studie über den Verlauf der Salpetrigsäurebildung aus Salpetersäure und durchströmendem Stickoxyd
Authors: Abel E. , Harasty D. 
Published: January 2005

AbstractAusgehend von der Fragestellung, von welchen Faktoren die Geschwindigkeit der Reduktion von Salpetersäure zu salpetriger Säure bei Durchleiten von Stickoxyd abhängt, wurde der Einfluß der Durchströmungsgeschwindigkeit des Gases, der Oberflächenausdehnung und des Reaktionsvolumens untersucht, und an der unter den eingehaltenen Versuchsbedingungen auch in ihrer Kinetik unvermeidlich heterogenen Reaktion festgestellt, daß ihre Geschwindigkeit sowohl mit der Konzentration der H.‐Ionen als mit der der NO3'‐Ionen symbat geht; gegenüber dem Anfangsgehalt an gelöstem Stickoxyd ist die Reaktion infolge der aus dem Gasstrom gewährleisteten Nachlieferung wenig empfindlich; die genannte Symbasie ist bezüglich des H.‐Ions — insbesondere im Bereiche schwacher Salpetersäurelösungen — erheblich ausgeprägter als hinsichtlich des NO3'‐Ions, vielleicht infolge spezifischer Verzögerungswirkungen, wie solche bei Sulfat im weiten Umfange nachgewiesen wurden. Das charakteristischste Merkmal der Reaktion ist ihre Autokatalyse durch ihr Reaktionsprodukt, die salpetrige Säure, deren Bruttoeinfluß sich durch Superposition einer positiv und einer negativ autokatalysierenden Komponente ergibt, an welch letzterem Anteil jedenfalls die Lage des angestrebten Gleichgewichts verantwortlich ist.
Selektive Bestimmung von Vanadium in Gegenwart von Eisen und Chrom. I. Bestimmung von Vanadium in Gegenwart von Eisen
Authors: Someya Kinichi 
Published: January 2005

AbstractDie Benutzung von Diphenylamin als Indikator bei der Titration von Vanadinsäure mit Ferrosulfat vermeidet den Fehler, den die übliche Methode mit Ferricyanid besitzt, und vergrößert die Genauigkeit der Bestimmung von Vanadium in Gegenwart von Eisen. Vanadinsäure kann auch erfolgreich bestimmt werden durch Zusatz eines Überschusses von Ferrosulfat und Rücktitration des Überschusses mit Kaliumbichromat in der Kälte.
Die Aktivierung von Atomen und Molekeln und der Mechanismus der chemischen Umwandlung
Authors: Dhar N. R. 
Published: January 2005

AbstractDie folgenden Ergebnisse stützen die Ansicht von der Existenz aktiver Atome und Molekeln in einem System:

Reaktionen zwischen Elektrolyten sind gewöhnlich zurückzuführen auf die Vereinigung von Ionen entgegengesetzter Ladung; sie haben viel größere Geschwindigkeiten als Reaktionen, an denen keine Ionen beteiligt sind. Die Ionen befinden sich im aktiven Zustand und sind daher geneigt, sich miteinander zu vereinigen.
Um die begrenzte Geschwindigkeit einer gewöhnlichen chemischen Reaktion zu erklären, muß angenommen werden, daß nicht alle Molekeln eines reagierenden Systems sich in demselben Zustand der Aktivierung befinden, und daß aktive und inaktive Molekeln in ein und demselben Medium auftreten. Die Zahl der aktiven Molekeln ist im Vergleich mit der Zahl der inaktiven Molekeln sehr gering. Chemische Unwandlungen finden nur statt zwischen aktiven Molekeln.
Bei gewöhnlichen thermischen Reaktionen werden die Molekeln vermutlich aktiviert durch die Absorption von infraroter Strahlung, die wegen der Temperatur stets in einem System vorhanden ist.
Untersuchungen über die Löslichkeit des Magnesiumhydroxyds. I. Von der Existenz verschiedener Modifikationen von Magnesiumhydroxyd
Authors: Gjaldbaek J. K. 
Published: January 2005

AbstractDas Magnesiumhydroxyd existiert in zwei Modifikationen mit wohldefinierter Löslichkeit, einer leichter löslichen Form, labilem Magnesiumhydroxyd, und einer schwerer löslichen Form, stabilem Magnesiumhydroxyd.
Über die Potentiometrische Einstellung von Titantrichloridlösungen
Authors: Kolthoff I. M. , Tomiček O. , Robinson Conmar 
Published: January 2005

AbstractKaliumbichromat ist als Ursubstanz zur Einstellung von Titanchlorid sehr geeignet. Zur Beschleunigung der Potentialeinstellung in der Nähe vom Äquivalenzpunkt ist der Zusatz von ein wenig Kupfersulfat von Vorteil. Bei der Einstellung von Titanchlorid mit Kupfersulfat erhält man einen kleinen Sprung und einen etwas zu niedrigen Titer.
Die Verteilung eines Stoffes zwischen zwei Lösungsmitteln und die Löslichkeit
Authors: Perschke Wlad. 
Published: January 2005

Abstract1. Es ist auf Grund der thermodynamischen Hauptätze ein theoretischer Beweis gegeben für die Gleichheit des Verteilungskoeffizienten eines Stoffes zwischen zwei nichtmischbaren Flüssigkeiten mit dem Löslichkeitsverhältnis desselben Stoffes in denselben Lösungsmitteln und bei derselben Temperatur.
Bemerkungen über das neue Massenwirkungsgesetz. III. Zur Theoretischen Berechnung der Isotherme
Authors: Lorenz Richard , Mannheimer M. 
Published: January 2005

AbstractWir fassen im nachfolgenden die Hauptergebnisse der Bemerkungen I, II, III zusammen.Bei der Berechnung der Konstanten r des neuen Massenwirkungsgesetzes lassen sich die Konstanten b der angenommenen Zustandsgleichung durch übereinstimmende Volume (beispielsweise Schmelzpunkts‐ oder Siedepunktsvolume) ersetzen.