bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of adenosine on bicuculline‐resistant paired‐pulse inhibition in the rat hippocampal slice
Authors: Higgins Michael J. , Stone Trevor W. 
Published: May 2005

AbstractThis study extends previous investigations into the effect of adenosine on bicuculline‐resistant paired‐pulse inhibition between field potentials evoked 300 ms apart in the CA1 area of the rat hippocampal slice. A direct assessment of the effect of adenosine on paired‐pulse inhibition is complicated by the facts that adenosine directly depresses evoked potentials and bicuculline‐resistant paired‐pulse inhibition is greather between pairs of small potentials than between pairs of larger potentials. Adenosine increased biculline‐resistant paired‐pulse inhibition when stimulus strength was constant between adenosine and control but paired‐pulse inhibition of responses in adenosine was markedly less than paired‐pulse inhibition of control responses of the same size. Futhermore, adenosine decreased the size of conditioned potentials to a significantly lesser extent than unparired potentials of the same initial size. Taken together the results indicate that adenosine can decrease bicuculline‐resistant paired‐pulse inhibition in the hippocampus. A possible mechanism for this effect is that adenosine is suppressing transmission at excitatory terminals onto interneurones which would suggest that these receptors are more sensitive to adenosine than those on the Schaffer collateral/CA1 pyramidal cell synapses. In this case adenosin should reduce paired‐pulse inhibition at lower concentrations than are required for depression of single evoked potentials. A comparison of the concentration‐response relationships for the effects of adenosine on paired‐pulse inhibition and on single evoked potentials ruled out greater sensitivity of adenosine receptors at excitatory terminals onto interneurones as an explanation for adenosine's action on bicuculline‐resistant paired‐pulse inhibition. Adenosine was less effective at reducing inhibition evoked by large supramaximal conditioning stimuli than by submaximal for evoked potential size, although control paired‐pulse inhibiton is larger in the later case. This finding is consistent with adenosine reducing bicuculline‐resistant paired‐pulse inhibition by causing an increase in simultaneous paired‐pulse facilitation. © 1995 Wiley‐Liss, Inc.
Postnatal development of CA3 pyramidal neurons and their afferents in the Ammon's horn of rhesus monkeys
Authors: Seress László , Ribak Charles E. 
Published: May 2005

AbstractPrevious studies described the postnatal development of CA3 pyramidal neurons and their afferents in the rat. However, the postnatal development of the primate hippocampus was not previously studied. Thus, pyramidal neurons of the CA3 area of the monkey hippocampus were analyzed postnatally in the present study. At birth, a few thorny excrescences, the complex spines postsynaptic to mossy fibers, were found on the proximal segments of both apical and basal dendrites, whereas distal dendrites displayed pedunculate spines. Thorny excrescences increased in number until the third month. A continuous increase in the number of spines per unit length along the distal dendrites was observed during the first 12 months. The ultrastructural features of somata and dendrites of pyramidal cells in newborn monkeys were similar to those of adults.The analysis of the afferents to the CA3 pyramidal neurons was limited to the development of mossy fibers, the axons of granule cells, and myelinated axons in the alveus, stratum oriens, and stratum lacunosum‐moleculare. At birth, most mossy fiber terminals were densely packed with synaptic vesicles and formed mainly axospinous synapses with CA3 pyramidal cells. By 1 month of age, the number of mitochondria and embedded spines increased to mature amounts. In the first postnatal month, degenerating axons and axon terminals were frequently observed in the mossy fiber bundles in stratum lucidum. The proportion of myelinated axons increased simultaneously in all three examined layers. At birth most axons were unmyelinated, whereas at 7 months of age the proportion of myelinated axons was similar to that found in adults.The present study indicates that most pyramidal neurons of the CA3 region in monkeys are in an advanced stage of development at the time of birth. Thus, mossy fibers from granule cells in the dentate gyrus have established mature‐looking synapses, and the thorny excrescences of pyramidal cells that are postsynaptic to mossy fibers are also adult‐like. Nevertheless, several of the adult features, such as the spine density of distal dendrites of pyramidal neurons and the myelination of afferent axons, develop during an extended period of time in the first year. The significance of this early anatomical maturation in a brain region involved in memory function is consistent with recent behavioral data that show a rapid postnatal maturation of limbic‐dependent recognition memory in rhesus monkeys. © 1995 Wiley‐Liss, Inc.
Connection matrix of the hippocampal formation: I. The dentate gyrus
Authors: Patton Paul E. , McNaughton Bruce 
Published: May 2005

AbstractThe hippocampal formation presents a special opportunity for realistic neural modeling since its structure, connectivity, and physiology are better understood than that of other cortical components. A review of the quantitative neuroanatomy of the rodent dentate gyrus (DG) is presented in the context of the development of a computational model of its connectivity. The DG is a three‐layered folded sheet of neural tissue. This sheet is represented as a rectangle, having a surface area of 37 mm2 and a septotemporal length of 12 mm. Points, representing cell somata, are distributed in the model rectangle in a roughly uniform fashion. Synaptic connectivity is generated by assigning each presynaptic cell a spatial zone representing its axonal arbor. For each postsynaptic cell, a list of potential presynaptic cells is compiled, based on which arbor zones the given postsynaptic cell falls within. An appropriate number of presynaptic inputs are then selected at random. The principal cells of the DG, the granule cells, are represented in the model, as are non‐principal cells, including basket cells, chandelier cells, mossy cells, and GABAergic peptidergic polymorphic (GPP) cells. The neurons of layer II of the entorhinal cortex are included also. The DG receives its main extrinsic input from these cells via the perforant path. The basket cells, chandelier cells, and GPP cells receive perforant path and granule cell input and exert both feedforward and feedback inhibition onto the granule cells. Mossy cells receive converging input from granule cells and send their output back primarily to distant septotemporal levels, where they contact both granule cells and non‐principal cells. To permit numerical simulations, the model must be scaled down while preserving its anatomical structure. A variety of methods for doing this exist. Hippocampal allometry provides valuable clues in this regard. © 1995 Wiley‐Liss, Inc.
Dehydroepiandrosterone sulfate suppresses hippocampal recurrent inhibition and synchronizes neuronal activity to theta rhythm
Authors: Steffensen Scott C. 
Published: May 2005

AbstractSeveral neurosteroids have proconvulsant and memory‐en‐hancing properties and are potent modulators of the γ‐amino butyric acid (GABA) receptor/chloride‐ionophore complex. The effects of in situ microelectrophoretic application of the natural sulfate ester of the neurosteroid dehydroepiandrosterone (DHEAS) on evoked field responses and single‐unit activity were evaluated in the dentate gyrus and CA1 hippocampal subfield of halothane‐anesthetized rats. The effects of endogenous stimulation of DHEAS by in situ micropressure application of Trilostane ((4α, 5α, 17β)‐4, 5‐epoxy‐3, 17‐dihydroxyandrost‐2‐ene‐2‐carbonitrile (WIN24540)), an inhibitor of 3β‐hydroxysteroid dehydrogenase/isomerase (3β‐HSD), the enzyme that metabolizes DHEAS, on evoked responses and cellular activity in the hippocampus were also investigated. In situ microelectrophoretic application of DHEAS or micropressure application of Trilostane into CA1 markedly increased population excitatory postsynaptic potential (pEPSP) slopes and population spike (PS) amplitudes. Neither DHEAS nor Trilostane altered dentate pEPSP slopes or PS amplitudes, but both increased the amplitude of a late component of the pEPSP. Both DHEAS and Trilostane abolished GABA‐mediated pairedpulse inhibition in both the dentate and CA1. In addition, both DHEAS and Trilostane markedly increased the spontaneous firing rate of dentate hilar interneurons (INTs: 256% and 185%), CA1 pyramidal cells (PCs: 95% and 105%), and CA1 oriens/alveus (O/A) interneurons (179% and 85%) and synchronized their firing to hippocampal theta rhythm induced by tail‐pinch. These findings indicate that exogenous application and endogenous stimulation of DHEAS modulates hippocampal GABA inhibition in a physiologically relevant manner possibly by entraining hippocampal neurons to theta rhythm. © 1995 Wiley‐Liss, Inc.
Stable maintenance of glutamate receptors and other synaptic components in long‐term hippocampal slices
Authors: Bahr Ben A. , Kessler Markus , Rivera Santiago , Vanderklish Peter W. , Hall Randy A. , Mutneja Manpreet Singh , Gall Christine , Hoffman Keith B. 
Published: May 2005

AbstractCultured hippocampal slices retain many in vivo features with regard to circuitry, synaptic plasticity, and pathological responsiveness, while remaining accessible to a variety of experimental manipulations. The present study used ligand binding, immunostaining, and in situ hybridization assays to determine the stability of AMPA‐ and NMDA‐type glutamate receptors and other synaptic proteins in slice cultures obtained from 11 day postnatal rats and maintained in culture for at least 4 weeks. Binding of the glutamate receptor ligands [3H]AMPA and [3H]MK‐801 exhibited a small and transient decrease immediately after slice preparation, but the binding levels recovered by culture day (CD) 5–10 and remained stable for at least 30 days in culture. Autoradiographic analyses with both ligands revealed labeling of dendritic fields similar to adult tissue. In addition, slices at CD 10–20 expressed a low to high affinity [3H]AMPA binding ratio that was comparable with that in the adult hippocampus (10:1). AMPA receptor subunits GluR1 and GluR2/3 and an NMDA receptor subunit (NMDAR1) exhibited similar postcutting decreases as that exhibited by the ligand binding levels, followed by stable recovery. The GluR4 AMPA receptor subunit was not evident during the first 10 CDs but slowly reached detectable levels thereafter in some slices. Immunocytochemistry and in situ hybridization techniques revealed adult‐like labeling of subunit proteins in dendritic processes and their mRNAs in neuronal cell body layers. Long‐term maintenance was evident for other synapse‐related proteins, including synaptophysin, neural cell adhesion molecule isoforms (NCAMs), and an AMPA receptor related antigen (GR53), as well as for certain structural and cytoskeletal components (e. g., myelin basic protein, spectrin, microtubule‐associated proteins). In summary, following an initial and brief depression, many synaptic components were expressed at steady‐state levels in long‐term hippocampal slices, thus allowing the use of such a culture system for investigations into mechanisms of brain synapses. © 1995 Wiley‐Liss, Inc.
Postischemic inhibition of GABA reuptake by tiagabine slows neuronal death in the gerbil hippocampus
Authors: Inglefield Jon R. , Perry Jean M. , Schwartz Rochelle D. 
Published: May 2005

AbstractThe neuroprotective effects of enhancing neuronal inhibition with a γ‐aminobutyric acid (GABA) uptake inhibitor were studied in gerbil hippocampus following transient ischemia. We used in vivo microdialysis to determine a suitable dosing regimen for tiagabine (NNC 328) to elevate extracellular levels of GABA within the hippocampus. In anesthetized (normothermic) gerbils, tiagabine (45 mg/kg, i. p.) selectively elevated extracellular GABA levels 450% in area CA1 of the hippocampus. In gerbils subjected to cerebral ischemia via 5‐min bilateral carotid occlusion, extracellular GABA levels increased 13‐fold in area CA1, returning to baseline within 30–45 min. When tiagabine was injected 10 min following onset of reperfusion, GABA levels remained elevated (200–470%) for 90 min. In addition, tiagabine significantly reduced the ischemic‐induced elevation of glutamate levels in area CA1 during the postischemic period when GABA levels were elevated. There was no effect of postischemic tiagabine on aspartate or six other amino acids. Using the same dosing regimen, we evaluated the degree of neuroprotection in the hippocampus of gerbils 4 and 21 days after ischemia. Tiagabine decreased body temperature a maximum of 2.7°C beginning 30 min into reperfusion and lasting 90 min. In untreated gerbils sacrificed 4 and 21 days after ischemia, there was severe necrosis (99%) of the pyramidal cell layer in area CA1. Whereas tiagabine significantly protected the CA1 pyramidal cell layer in ischemic gerbils at 4 days (overt necrosis confined to about 17% of area CA1), the protection diminished significantly 21 days postischemia. When normothermia was maintained both during and after ischemia in a separate group of tiagabine‐treated animals, approximately 77% of the CA1 pyramidal cell layer was necrotic at 4 days. Based on these findings, we suggest that (1) tiagabine slows the development of hippocampal degeneration following ischemia, and (2) that mild, postischemic hypothermia is responsible, in large part, for the neuroprotective actions of this drug. We conclude that the histological outcome after administration of cerebral neuroprotectants should be assessed following long‐term survival. © 1995 Wiley‐Liss, Inc.
(Des‐tyr1)‐gamma‐endorphin (DTγE) in the treatment of depression: Double‐blind placebo‐controlled trial
Authors: Manchanda Rahul , Hirsch Steven 
Published: May 2005

AbstractPreliminary evidence of a mood‐elevating effect for the endogenous neuropeptide, (des‐tyr1)‐gamma‐endorphin, was further investigated in a double‐blind placebo‐controlled trial over a period of 2 weeks. There were 10 patients in each group. Between‐group comparisons on the change in scores by day 14 were non‐significant. There was, however, a significant reduction (p = 0.05, two‐tailed) of scores on the Montgomery Asberg Depression Rating Scale and the anxious‐depression subscale of the BPRS in the endorphin group. It is recommended that the trial be conducted in a larger sample for definitive results.
A double‐blind comparative trial of remoxipride and haloperidol in the treatment of schizophrenia
Authors: Deo R. , Soni S. , Rastogi S. C. , Levine S. , Plant I. , Edwards J. Guy , Mitchell M. J. , Chanas A. 
Published: May 2005

AbstractA multicentre parallel group study was carried out to compare the efficacy and safety of remoxipride, a new antipsychotic drug, with haloperidol in the treatment of acute schizophrenia. Patients were randomly assigned to the two groups and assessments were made under double‐blind conditions. Treatment was preceded by a washout period and lasted 6 weeks. Eighty‐nine consecutively admitted men and women meeting the Research Diagnostic Criteria for schizophrenia in an acute phase of the illness were treated with remoxipride 75–300 mg b.d. or haloperidol 5–20 mg b.d. The main assessments were changes in scores on the Brief Psychiatric Rating Scale, Krawiecka Rating Scale and Clinical Global Impression. Both neuroleptics produced clinical improvement but there were no significant differences in overall efficacy measurements between the two drugs. There were relatively few unwanted side‐effects. There were significantly less extra‐pyramidal symptoms and blurred vision with remoxipride, and less constipation with haloperidol. The results indicate that remoxipride is an effective antipsychotic drug with a low incidence of extrapyramidal side‐effects.
Age and anxiety: Increased anxiety, decreased anxiolytic, but enhanced sedative, response to chlordiazepoxide in old rats
Authors: File S. E. 
Published: May 2005

AbstractThe effects of chlordiazepoxide (7.5 mg/ kg) were assessed on the performance of young (3 months) and old (12 months) hooded Lister rats in the elevated plus‐maze test of anxiety. In young animals chlordiazepoxide significantly increased the percentage of entries onto open arms and the percentage of time spent on the open arms of the plus‐maze, measures that reflect its anxiolytic action. In the young animals this dose of chlordiazepoxide did not change the total number of arm entries, a measure that reflects its sedative action. However, in the old animals the only significant effect was a reduction in total arm entries. The effects of ageing on performance in the plus‐maze was assessed by testing rats at 3, 6, 9 and 12 months of age. Between 9 and 12 months the rats showed a significant decrease in the percentage of entries onto open arms and in the percentage of time spent on the open arms, indicating an increase in this measure of anxiety. Thus it seems that old rats might have an increase in their baseline measures of anxiety, coupled with a reduced anxiolytic response to benzodiazepines.
Tyramine‐Induced cardiac arrhythmias
Authors: Tiller J. W. G. , Maguire K. P. , Davies B. M. , Dowling J. T. , Tung L. H. , Rand M. J. 
Published: May 2005

AbstractFive out of 12 physically healthy patients with depression undergoing a tyramine pressor test developed cardiac arrhythmias. These arrhythmias occurred in drug‐free patients in three out of 12 infusions following as little as 0.03 mg/kg of tyramine and after moclobemide, a reversible inhibitor of monoamine oxidase‐A, in four out of 14 tyramine infusions with as little as 0.04 mg/kg of tyramine. The arrhythmias seen were independent of patient's age and occurred both before and after 30 mmHg elevations in systolic blood pressure. Electrocardiographic abnormalities and arrhythmias seen were a loss of p waves, sinus tachycardia, frequent atrial ectopic beats, atrial premature beats, Wenckebach phenomenon, junctional rhythm, ventricular ectopics, varying QRS configurations, and ventricular bigeminy. Tyramine, both oral and intravenous, caused similar reproducible changes in dogs, though not in rats, mice or guinea pigs. Practical implications are that tyramine pressor testing in humans should be performed cautiously and only with adequate cardiac monitoring and resuscitation facilities at hand. These findings suggest that a normal dietary component can induce serious cardiac arrhythmias, and that a low‐tyramine diet may be of value for patients who are susceptible to cardiac arrhythmias.
High‐dose anabolic steroids in strength athletes: Effects upon hostility and aggression
Authors: Choi P. Y. L. , Parrott A. C. , Cowan D. 
Published: May 2005

AbstractSix male strength athletes, three illicit anabolic steroid users and three non‐steroid users were monitored over several months as they underwent normal training and competition routines. Subjects completed the Profile of Mood States (POMS) questionnaire, Buss‐Durke Hostility Inventory and the Rosenweig Picture Frustration Test on four occasions: two on‐drug periods and two off‐drug periods for the steroid users and equivalent test periods for the non‐users. Steroid presence was monitored objectively by gas chromatography coupled to mass spectrometry. Whilst those drugs declared by the athletes were confirmed in the “on‐drug” samples and most of the “off‐drug” samples, clear steroid traces were apparent in some supposed off‐drug sessions. This complicated data interpretation and may partially explain why steroid users were significantly more hostile and aggressive at all times compared to the non‐users. Despite this, self‐rated aggression did increase significantly in steroid users during their acknowledged on‐drug periods. Multiple drug use or “stacking” in particular caused severe hostility/aggression; one steroid user also admitted to attempted murder during a previous steroid‐taking phase.
Effect of hydroxyzine on attention and memory
Authors: De Brabander A. , Deberdt W. 
Published: May 2005

AbstractA single intake of hydroxyzine 50 mg was compared to placebo, with lorazepam 2 mg as a verum, in a double‐blind, triple‐crossover trial. Each of the nine volunteers was tested on three different days, once under each condition. At 2‐h after drug intake all volunteers were assessed or reassessed for attention, immediate and delayed (30 min) memory, cognitive ability and subjective feelings of anxiety and fatigue. While hydroxyzine 50 mg and lorazepam 2 mg produced a comparable level of sedation, only hydroxyzine preserved memory and attention. The testing methods were sufficiently sensitive to demonstrate clear deficiencies in attention and short‐term and long‐term memory with lorazepam. Subjects became some what stressed under both sedative treatments because they feared losing their cognitive abilities. Subjects had fewer complaints under hydroxyzine than under lorazepam.
Effect of ceruletide on microvibration in schizophrenics
Authors: Nishikawa T. , Kuwahara H. , Tsuda A. , Tanaka M. , Koga I. , Uchida Y. 
Published: May 2005

AbstractCeruletide, a potent analogue of cholecystokinin, was administered by injection to eight schizophrenics treated with neuroleptics. We examined the dose–response effect on microvibration (MV) recorded from the chin of these patients. After 15 min of bed rest, MV was recorded for 5 min as a control recording. Subsequently, saline or ceruletide, at a dose of either 0.4 m̈g/kg or at 0.8 m̈g/kg, was injected according to a Latin square design with an interval of 4 weeks for washing out the drug effect and MV was recorded for 30 min. MV data obtained were subjected to the fast Fourier transform and an average power spectrum was computed. A three‐way analysis of variance for these data was performed upon dose‐effect, time‐effect after treatment, and band‐effect of the average power spectrum. The present results were similar to previous findings which had revealed effects of ceruletide on tardive dyskinesia symptoms, namely, the effects of ceruletide on MV were different according to the subjects (three cases: facilitation followed by inhibition, three cases: inhibition, two cases: no effects). The dose‐response curve of ceruletide appears to be linear in some cases and an inverted U‐shape in other cases. Present findings showed small doses of systemically administered ceruletide would modify muscle tonus of schizophrenics under chronic treatment of neuroleptics, and provided further reason for the therapeutic drug of tardive dyskinesia.
Comparison of mianserin and dothiepin treatment on the serotonergic system in depressed patients
Authors: Butler J. , Leonard B. E. 
Published: May 2005

AbstractDepressed patients showed a decreased 5‐HT uptake rate and aggregation response and increased platelet ketanserin binding, compared to normal controls. Five weeks treatment with either mianserin or dothiepin improved the biochemical parameters in the patients, although the parameters still had not returned to control levels. There was no difference between the biochemical markers in the mianserin and dothiepin groups at any time during the study.