bluuebunny/crossref_metadata_2025 huggingface dataset:
Regulation of luteinizing hormone secretion by neuropeptide Y in rats: Hypothalamic and pituitary actions
Authors: Crowley William R. , Kalra Satya P.
Published: January 2005

Previous studies have suggested that the stimulatory effect of neuropeptide Y (NPY) on the release of luteinizing hormone (LH) in rats may be due to a central action of the peptide that promotes the release of LH‐releasing hormone (LHRH) from the hypothalamus, and to an action in the pituitary gland, to potentiate the release of LH induced by LHRH. The objectives of the present experiments were to test (1) whether NPY stimulation of LHRH release requires extracellular Ca++, and (2) whether NPY can exert direct stimulatory effects on the release of LH from anterior pituitary cells. The in vitro release of LHRH from medial basal hypothalamic fragments induced by KCl depolarization (56 mM), but not the basal release, was blocked by omission of Ca++ and addition of 0.1 mM EGTA to the incubation medium and also by cobalt (1 mM). Depolarizationinduced release of the peptide was unaffected by nifedipine, diltiazem, or lanthanum. However, the stimulation of LHRH release by NPY (1 μM) still occurred in Ca++ free/EGTA medium. In a second set of experiments, 10 min pulses of NPY (1–100 nM) alone were ineffective in stimulating the release of LH from dispersed, perifused anterior pituitary cells obtained from ovariectomized, untreated or ovariectomized, estrogen‐treated rats, under conditions where pulses of LHRH (0.1–10 nM) were consistently effective. A brief increase in LH release was observed during a 30 min exposure to 100 nM NPY in estrogen‐pretreated cells, but not from untreated cells, and the effect was not as marked as that produced by LHRH. The present results confirm previous observations that NPY stimulates the release of LHRH from medial basal hypothalamus in vitro and suggests that NPY does not activate the influx of extracellular Ca++ in order to produce this effect. NPY may also directly stimulate the release of LH from anterior pituitary cells, but is weaker than the physiological releasing hormone, LHRH. The dual actions of NPY may have physiological significance in mediating ovarian hormone positive feedback on LH secretion during the estrous cycle.
Distribution of dopamine D1 receptors in rat cortical areas, neostriatum, olfactory bulb and hippocampus in relation to endogenous dopamine contents
Authors: Diop Laurent , Gottberg Estela , Brière Richard , Grondin Louise , Reader Tomas A.
Published: January 2005

The tritiated dopamine D1 antagonist SCH23390 was employed to determine the densities of D1 receptors in seven discrete and functionally identified cortical areas (cingulate, frontal, parietal, primary somatosensory, primary visual, retrosplenial and entorhinal‐piriform) as well as in the neostriatum, hippocampus and olfactory bulbs. In addition, the tissue levels of the catecholamines NA, AD, DA, the indoleamine 5‐HT and their main metabolites (MHPG, DOPAC, HVA, 3‐MT, 5‐HTP and 5‐HIAA) were measured in the different regions by HPLC with electrochemical detection. The Scatchard analysis of saturation curves revealed the highest density of [3H]SCH23390 binding sites for the neostriatum, while the densities were 10×20 times lower for total cerebral cortex and hippocampus respectively. For the olfactory bulb and other cortical areas, D1 receptor densities were determined by equilibrium binding at a fixed radioligand concentration approaching saturation. The distribution of D1 receptors was heterogeneous with the greatest densities in entorhinal‐piriform and cingulate cortices. The endogenous DA levels measured for all regions correlated with their metabolite (DOPAC, HVA and 3‐MT) contents (r = 0.999; P < 0.001). There was also a very good correlation (r = 0.981; P < 0.001) between tissue DA and D1 receptor densities. This quantitative information reflects particular features of the organization of the DA systems and is discussed in relation to turnover and recently established aspects of the DA innervation.
Acute effects of lithium on dopaminergic responses: Iontophoretic studies in the rat visual cortex
Authors: Gottberg Estela , Montreuil Bernard , Reader Tomas A.
Published: January 2005

The interactions between lithium and cortical dopaminergic receptors were investigated using the iontophoretic technique to record and apply dopaminergic compounds, GABA, acetylcholine and LiCL on neurons in the primary visual cortex of the rat. The main responses to dopamine (DA) or to the D1 agonist (±)SKF38393 on spontaneously‐active (SA) or visually‐driven (VD) units was a prolonged decrease in firing and a reduction in the responsiveness to pulses of acetylcholine. The D1 antagonist SCH23390, applied iontophoretically or intravenously, blocked or attenuated the inhibitory responses to both DA and (±)SKF38393. The D2 agonist quinpirole (LY171555) either produced only slight excitations or had no effects on both VD and SA units. The concomitant application of lithium blocked the inhibitory responses to DA and to (±)SKF38393 but did not modify the responsiveness to LY171555. In addition, the DA‐ and (±)SKF38393‐induced decreases in responsiveness to acetylchline were also suppressed by lithium. These effects were on dopaminergic mechanisms, since the excitatory responses to acetylcholine alone as well as the inhibitions causes by GABA were unchanged by the application of lithium. These results imply that the modifications in sensitivity to dopaminergic agents induced by lithium are mediated by dopamine D1 receptors and are discussed in relation to adenylatecyclase.
Quantitation of nerve terminal populations: Synaptic vesicle‐associated proteins as markers for synaptic density in the rat neostriatum
Authors: Walaas S. Ivar , Jahn Reinhard , Greengard Paul
Published: January 2005

This study has assessed the contributions of the corticostriatal fibers, the ascending striatopetal fibers, and the intrinsic neostriatal neurons to the nerve terminal population found in the rat neostriatum (caudatoputamen). For this purpose, we have analysed the levels of two different synaptic vesicle‐associated proteins, synapsin I and protein p38 (also called synaptophysin), in the neostriatum after specific lesions. Our results indicate that 45–50% of the synaptic vesicle proteins in the rat neostriatum derive from the corticostriatal fibers, that approximately 25–30% of the synaptic vesicle proteins are present in kainic acid‐sensitive structures, presumably intrinsic terminals and local collaterals, and that ascending fibers contain 20–25% of the vesicle‐associated proteins in the neostriatum. These three neuronal populations therefore comprise 95–100% of the synaptic vesicle‐associated proteins in the rat neostriatum, and thus make up most of the nerve terminals in this brain region. The results, which are in general agreement with previous morphometric studies on the rat basal ganglia, therefore indicate that nerve terminals in the central nervous system can be quantitated by use of these biochemical nerve terminal markers. The results also indicate that a somewhat higher percentage of neostriatal nerve terminals belongs to the corticostriatal fibers than previously believed.
Serotoninergic neurites in senile plaques in cingulate cortex of aged nonhuman primate
Authors: Kitt Cheryl A. , Walker Lary C. , Molliver Mark E. , Price Donald L.
Published: January 2005

In immunocytochemical studies, a polyclonal antiserotonin antibody was used to visualize fibers within the cingulate cortex of young and aged rhesus monkeys. Intricate and distinct patterns of serotoninergic processes were seen in anterior and posterior segments of cingulate cortex (Brodmann areas 24 and 23). In these regions of cortex, many multivaricose serotonin‐immunoreactive axonal swellings were identified, and some of these immunostained neurites were associated with deposits of amyloid. These observations suggest that serotoninergic processes are involved in the formation of senile plaques in neocortex of aged macaques.
Localization and regulation of vasopressin mRNA in human neurons
Authors: Rivkees Scott A. , Chaar Maamoun R. , Hanley Daniel F. , Maxwell Marius , Reppert Steven M. , Uhl George R.
Published: January 2005

Vasopressin (prepropressophysin) mRNA is detected in neurons of the supraoptic, suprachiasmatic, and paraventricular nuclei of human postmortem hypothalamic specimens by quantitated in situ hybridization using 35S‐labeled single‐stranded cDNA probes directed against exon C of the human vasopressin gene. This hybridization displays the anticipated anatomic distribution, as well as several biochemical features supporting its specificity. Hybridization densities in supraoptic neurons, a measure of vasopressin gene expression, display substantial variability from‐brain‐to‐brain. We can attribute much of this brain‐to‐brain variability to differences in antemortem extracellular volume status. This conclusion is based on (a) animal models of the human postmortem process, (b) animal models of common agonal events, (c) good correlations between antemortem volume status and neuronal vasopressin mRNA hybridization densities in human postmortem specimens matched for age and postmortem interval, and (d) our inability to correlate human neuronal vasopressin mRNA hybridization densities with other clinical and postmortem features. These results provide an example of antemortem regulation of a human neuroendocrine gene using postmortem tissue.
Dye‐Coupling in the neostriatum of the rat: II. Decreased coupling between neurons during development
Authors: Walsh John P. , Cepeda Carlos , Hull Chester D. , Fisher Robin S. , Levine Michael S. , Buchwald Nathaniel A.
Published: January 2005

Physiological and morphological evidence for coupling between neostriatal neurons was obtained from the developing rat. Intracellular injections of Lucifer Yellow‐CH (LY) were made in rat neostriatal slices to study dye transfer (coupling) between neurons. The incidence of interneuronal coupling was 70% in early postnatal (P) periods and declined gradually to 10% in the adult. The number of neurons filled by a single intracellular injection also declined with age. LY injection into single neurons commonly marked aggregates of 4 to 6 cells in neonates. Single injections never produced more than one coupled pair in P20 or older rats. Neurons in which fast prepotentials (FPPs) could be evoked were consistently found to be dye‐coupled. FPPs were resistant to collision with action potentials generated by intracellular current injection. When chemical synaptic transmission was blocked by Mn2+, short‐latency depolarization (SLDs) could be evoked by extracellular stimulation. The SLDs were distinguished from chemical synaptic potentials by their “all or none” nature and by their insensitivity to changes in membrane potential. No SLDs were observed in adult neurons. FPPs and SLDs may be indicators of electrotonic transmission between coupled cells. The high incidence of coupling early in development might reflect intercellular communication that contributes to the differentiation and growth of neostriatal neurons.
Distribution of dopamine D1 and D2 receptors in rabbit cortical areas, hippocampus, and neostriatum in relation to dopamine contents
Authors: Dewar Karen M. , Reader Tomás A.
Published: January 2005

The densities of dopamine D1 and D2 receptors were measured by using [3H]SCH23390 and [3H]reclopride, respectively, in the rabbit cingulate, visual, sensorimotor, and entorhinal‐piriform cortical areas; the dorsal and ventral hippocampus; and the putamen as well as the medial and lateral caudate. Endogenous dopamine (DA) and its metabolites 3,4‐dihydroxyphenylacetic acid (DOPAC), 4‐hydroxy‐3‐methoxyphenylacetic acid (HVA), and 3‐methoxytyramine (3‐MT) were assayed by HPLC with electrochemical detection. The distributions of [3H]SCH23390 and [3H]raclopride binding were heterogenous with the greatest densities in the neostriatum. The concentrations of DA and its metabolities were also highest in this structure. Regions with low DA content, i.e., cortex and hippocampus, had lower densities of [3H]SCH23390 and [3H]raclopride binding. Furthermore, these sites were differentially localized within the various regions and there were substantially more D1 and D2 receptors. The functional significance and heterogeneities in the distribution of D1 and D2 receptors are discussed in relation to the dopaminergic innervation and the turnover estimated by the ratios between endogenous DA and its metabolites.
Effect of acute and daily cocaine treatment on extracellular dopamine in the nucleus accumbens
Authors: Kalivas Peter W. , Duffy Patricia
Published: January 2005

The behavioral stimulant effect of peripheral cocaine injection into rats is augmented following daily adminstration. In vivo dialysis in the nucleus accumbens of conscious rats was used to determine if the increased behavioral response following daily cocaine administration is associated with in increase in extracellular dopamine concentration. Acute injection of cocaine (15 mg/kg, ip) produced and elevation in extracellular dopamine concentration in the nucleus accumbens. Following daily pretreatment with cocaine (15 mg/kg, ip × 4 days), a subsequent acute injection of cocaine (15 mg/kg, ip) significantly elevated the extracellular dopamine levels compared to that produced by a single acute injection. Although the levels extracellular dopamine metabolites was significantly lowered by both acute cocaine and daily cocaine, no difference between these two groups of animals was measured. The increase in extrecellular dopamine following a single acute injection of cocaine was not correlated to the motor stimulant response. However, after daily pretreatment with cocaine the motor stimulant response to acute cacaine was positively correlated with the increased extracellular concentration of dopamine in the nucleus accumbens. These data demonstrate that enhanced dopamine release into the nucleus accumbens may mediate the behavioral sensitization produced by daily injections of cocaine, but that other neural systems are influential in mediating the acute motor stimulant effect of cocaine.
Electrophysiological actions of luteinizing hormone‐realeasing hormone: Intracellular studies in the rat hippocampal slice preparation
Authors: Wong Michael , Eaton Misty J. , Moss Robert L.
Published: January 2005

The electrophysilogical effects of luteinizing hormone‐releasing hormone (LHRH) on CA1 pyramidal cells were investigated utilizing intracellular recodings from the in vitro rat hippocampal slce preparation. Bath application of LHRH (10‐7‐10‐12M) resulted in several changes in the electrophysiological properties of CA1 neurons. LHRH induced a long‐lasting depolarization associated with increased input resitance, and decrease in the afterhyperpolarization associated with increased input resistance, ad decrease in the afterhyperpolarization (AHP) following a train of action potentials, and a reduction in accommodation of repetitive cell discharge. These effects were blocked by the synthetic LHRH antagonist [Ac‐δ‐Pro1, pCl‐D‐Phe2, D‐Trp3,6]‐LHRH. These findings provide electrophysiological evidence for the role of LHRH as a neurotransmitter/neuromodulator in the hippocampus.
Glycine site associated with the NMDA receptor modulates long‐term potentiation
Authors: Oliver M. W. , Kessler M. , Larson J. , Schottler F. , Lynch G.
Published: January 2005

Recent work has shown that kynurenic acid and several quinoxaline derivatives act as non‐competitive NMDA receptor antagonists by binding to the glycine site associated with this receptor. In this study, we have tested the effect of the most potent and selective of these compounds, 7‐chlorokynurenic acid (C1‐Kyn), on the induction of long‐term potentiation, an event know to involve activation of NMDA receptors. It was found that 30 m̈M C1‐Kyn reversibly abolished the development of both short‐term and long‐term potentiation in the CA1 region of hippocampal slices. The effectiveness of C1‐Kyn matched its ability to inhibit 3H‐glycine binding and the association of 3H‐TCP with the NDMA receptor in binding experiments (Ki 0.7–1 μM). Weak interactions of C1‐Kyn with AMPA receptor sites were observed and may account for a partial, reversible reduction in the epsp. However, blockade of long‐term potentiation by C1‐Kyn was completely reversed by simultaneous application of the glycine site agonist D‐serine and thus must be attributed to its interaction with the glycine site. These results indicate that the glycine site coupled to the NMDA receptor potently modulates channel function during physiological events related to synaptic activation.
Serotonin excitation of facial motoneurons: Receptor subtype characterization
Authors: Rasmussen Kurt , Aghajanian George K.
Published: January 2005

The receptor subtype (s) mediating the enhancement of facial motoneuron exctitability by serotonin (5‐HT) was evaluated by means of single‐cell recording in vivo (in the anesthetized rat) and in vitro in brain slices. In vivo, microiontophoretic application of the broad‐spectrum 5‐HT1 agonist 5‐carboxamidotryptamine (5‐CT), the 5‐HT2/5‐HT1c agonist 1‐[2,5‐demethoxy‐4‐methylphenyl]‐2‐aminopropane (DOM), but not the selective 5‐HT1A agonist 8‐OH‐2[di‐n‐propylamino]tetralin (8‐OH‐DPAT), produced a 5‐HT‐like enhancement of facial motoneuron excitability. Intravenous administration of the 5‐HT2/ 5‐HT1c antagonists ritanserin and LY 53857 in vivo blocked the facilitatory effects of 5‐HT and DOM, but not norepinephrine (NE). Similarly, in brain slices, bath application of ritanserin blocked the effects of 5‐HT, DOM, and 5‐CT, but not NE on facial motoneurons. Intracellular recordings showed that DOM induced a slow depolarization and an increase in evoked spikes, but these effects were of lesser magnitude and longer duration than those produced by 5‐HT. Taken together these result indicate a a role for 5‐HT2 and/or 5‐HT1c but not 5‐HT1A receptors in serotonergic enhancement of facial motoneuron excitability since 5‐HTs effect was (1) at least partially mimicked by the selective 5‐HT2/5‐HTlc agonist DOM, (2) mimicked by the broad‐spectrum 5‐HT1 agonist 5‐CT but not the selective 5‐HTlA agonist 8‐OH‐DPAT, and (3) blocked by the 5‐HT2/5‐HT1c antagonists ritanserin and LY 53857.
Modulation of gonadotropin‐releasing hormone neuronal activity as evidenced by uptake of fluorogold from the vasculature
Authors: Silverman Ann‐Judith , Witkin Joan W. , Silverman Rachel C. , Gibson Marie J.
Published: January 2005

Peripheral injections of the tracer fluorogold (EG) and immunocytochemistry were used to study the modulation gonadotropin‐releasing hormone (GnRH) cell secretory activity in adult mice. Intraperitoneal adminstration of FG would make it available to all GnRH terminals outside the blood‐brain barrier. The degree of capture of the dye would be linked to exocytotic (e.g., secretory) events at the nerve terminal. Single injections of tracer were made into intact mice of both sexes, and this resulted in the retrograde labeling of two‐thirds of the GnRH cell bodies. Administration of identical doses to 3 week castrate mice revealed a reduction in the percentage of GnRH cells, with detectable FG, to 40% of the total. Castration did not diminish the number of GnRH cells visualized. When castrate animals received two doses of FG, the number of GnRH cells with tracer was increased to slightly greater than intact levels. This suggests that the secretory rate of individual GnRH cells might be reduced under coditions of castration. In addition, when ovariectomized females treated with estrogen and progeserone to induce luteinizing hormone (LH) surge were injected with FG just prior to that surge, over 80% of the GnRH neurons were robustly labeled with FG. These latter data are interpreted as representing GnRH neurons at maximally synchronized activity. This study suggests that peripheral administration of FG can be used in this species to follow alterations in neurosecretory rates.
Synaptic interactions between GABAergic neurons and trigeminothalamic cells in the rat trigeminal Nucleus Caudalis
Authors: DiFiglia Marian , Aronin Neil
Published: January 2005

Synaptic interactions between GABAergic neurons and thalamic projecting cells within the trigeminal nucleus caudalis were examined using a combined method of GABA immunohistochemistry and retrograde WGA‐HRP labeling of the trigeminothalamic pathway. Results showed that GABA‐positive neurons and projecting cells were separate but closely intermingled within the spinal trigeminal nucleus. GABAergic axon terminals formed symmetric synaptic connections with the cell bodies and dendrites of trigeminothalamic neurons. In turn, some WGA‐HRP filled axon terminals, presumed to originate from axon collaterals of the projecting neurons, formed synaptic connections with GABA containing neurons. The results suggest that in the spinal trigeminal nucleus there is a reciprocal modulation between GABA neurons and trigeminothalamic cells.
Immunoreactive calcium‐binding protein (calbindin‐D28k) in interneurons and trigeminothalamic neurons of the rat nucleus caudalis localized with peroxidase and immunogold methods
Authors: Aronin Neil , Chase Kathryn , Folsom Robin , Christakos Sylvia , Difiglia Marian
Published: January 2005

Calbindin‐D28k is a highly abundant protein found in neurons in selected brain regions, including cells in sensory system of the brainstem. Because of its capacity to bind cytosolic ca++, calbindin‐D28k is thought to contribute to the regulation of compartmental Ca++ concentration in neurons. In this study of the rat spinal trigeminal nucleus, calbindin‐D28k was localized with immunoperoxidase and immunogold methods. Results showed that immunoreactive calbindin‐D28k neurons were widely distributed to all region of the nucleus, but were particularly numerous in the substantia gelatinosa. Some trigeminothalamic neurons that were identified by retrograde labeling of conjugated wheat‐ germ agglutinin with horseadish perosidase also contained calbindin‐D28k immunoreactivity. Most of the calbindin‐D28k labeling was found in cell bodies and dendrites. Axon terminal were rarely stainded. More discreate labeling with a gold conjugated second antibody showed that the predominant site of calbindin‐D28k was the matrix of the cytoplasm. Gold label was also heavily associated with euchromatin within nuclei.

These finding show that immunoreactive calbindin‐D28k is localized to both interneurons and projecting neurons of the spinal trigeminal nucleus. Many of these cells are likely to receive glutamatergic afferent inputs, which may act in part by increasing Ca++ and under some condition may protect neurons against glutamate‐induced excitotoxicity. We speculate that calbindin‐D28k may function to regulate calcium concentration in spinal trigeminal neurons.
The role of interactions between the cholinergic system and other neuromodulatory systems in learing and memory
Authors: Decker Michael W. , McGaugh James L.
Published: January 2005

Extensive evidence indicates that disruption of cholinergic funtion is characteristic of aging and Alzheimer's disease (AD), and experimental manipulation of the cholinergic system in laboratory animals suggests age‐related cholinergic dysfunction may play an important role in cognitive deterioration associated with aging and AD. Recent research, however, suggests that cholinergic dysfunction does not provide a complete account of age‐related congnitive deficits and that age‐related changes in cholinergic function typically occur within the context of changes in several other neurmoudulatory systems. Evidence reviewed in this paper suggests that interactions between the cholinergic system and serveral of these neurotransmitters and neuromodulators—including norepinephrine, dopamine, serotonin, GABA, opioid peptides, galanin, substance P, and angiotensin II—may be important in learning and memory. Thus, it is important to consider not only the independent contributions of age‐related changes in neuromodulatory systems to cognitive decline, but also the contribution of interactions between these systems to the learning and memory deficits associated with again and AD.
NMDA‐receptor‐mediated sensory responses of brain noradrenergic neurons are suppressed by in vivo concentrations of extracellular magnesium
Authors: Shiekhattar Ramin , Aston‐Jones Gary
Published: January 2005

Recent studies reveal at least three receptor subtypes for excitatory amino acid (EAA) neurotransmitters. Activation of one of these, the N‐methyl‐D‐aspartate (NMDA) receptor‐channel complex, has been strongly implicated in neuronal mechanisms of several important brain processes, including learning and memory. As NMDA receptors are highly sensitive to extracellular magnesium (Mg++), we tested whether in vivo concentrations of this ion are sufficient to suppress NMDA‐receptor‐mediated responses. We show that slow, local microinfusion of Mg++‐free artificial cerebrospinal fluid onto noradrenergic locus coeruleus (LC) neurons reveals an NMDA‐receptor‐mediated component of their response to a sensory stimulus. This is the first demonstration that the in vivo concentration of extracellular Mg++ ions suppresses synaptically mediated NMDA receptor activation. We also present evidence that unmasking this NMDA receptor activity induces prolonged enhancement of the EAA‐mediated sensory response of LC neurons.
Quantitative autoradiography of cocaine binding sites in human brain postmortem
Authors: Biegon Anat , Dillon Kathryn , Volkow Nora D. , Hitzemann Robert J. , Fowler Joanna S. , Wolf Alfred P.
Published: January 2005

Quantitative autoradiography was used to study cocaine binding sites in the human brain postmortem. Triated cocaine was applied to brain sections from three drug‐ and disease‐free subjects at a low (10 nM) concentration and at a high (1 μM) concentration, the latter being in the range of brain concentrations of cocaine found in users of the drug. Nonspecific binding was assessed in the presence of 100 μM unlabeled cocaine. At low (10 nM) concentrations of labeled cocaine, the basal ganglia exhibit the highest density of binding sites, with considerably lower densities in thalamus, cortex, and hippocampus. Cocaine binding at high (1 μM) concentrations displayed a different distribution pattern, more homogeneous with some cortical regions exhibiting binding site densities close to those seen in the basal ganglia. Preliminary competition experiments with several drugs indicate that dopamine uptake inhibitors completely block cocaine binding to the basal ganglia, while serotonin uptake inhibitors were more effective in the hippocampus. These findings suggest that cocaine binds to dopamine uptake sites in the human basal ganglia postmortem but that it also interacts with other classes of binding sites, depending on the concentration and brain region examined.
Growth cones and structural variation of synaptic end‐bulbs in the cochlear nucleus of the adult cat brain
Authors: Jones Doyle R. , Hutson Kendall A. , Morest D. Kent
Published: January 2005

To explore the potential for structural variation and new growth at the synapse, we studied the morphological patterns of the end‐bulbs of cochlear nerve axons in adult cats by using rapid Golgi, reduced silver, and electron microscopic methods. Horseradish peroxidase labeling of these endings in the anterior division of the antroventral cochlear nucleus was produced by anterograde transport following injection into the cochlea. Three types of end‐bulbs were distinguished, regardless of method: reticular, coalescent, and ringed forms, all synapsing on spherical bushy cells. The reticular variety corresponds to the classically described end‐bulb and constitutes the majority in all regions of the tonotopic map. The ringed end‐bulb, described here for the first time, forms an excitatory synaptic cuff around the base of a bushy cell's main dendrite; these endings were localized to the region receiving cochlear input in the 1–6 kHz range, which is used in vocalization. The coalescent ending forms a small fraction of the end‐bulb population throughout the region studied. The findings raise the possibility of functional differences between these snyaptic types.

Growth cones and retraction clubs were present on most, if not all, of the end‐bulbs in every adult cat studied. A systematic survey of the end‐bulb patterns revealed a continuous gradient of variation, in which each synaptic type forms a distinct mode. These findings lead us to hypothesize that the end‐bulbs are in a continual state of structural and functional flux. These endings should prove useful for studies on the modifiable properties of central synapses.
Noncompartmental and compartmental modeling of the kinetics of carbon‐11 labeled pyrilamine in the human brain
Authors: Szabo Zsolt , Ravert Hayden T. , Gözükara Ibrahim , Geckle William , Seki Chie , Sostre Samuel , Peller Patrick , Monsein Lee , Natarajan T. K. , Links Jonathan M. , Wong Dean F. , Dannals Robert F. , Wagner Henry N.
Published: January 2005

The kinetic pattern of a 11C‐labeled histamine H1 receptor antagonist, [11C]pyrilamine, was investigated in the human brain by factor analysis of dynamic PET studies. Tissue time activity curves were also processed by compartment model curve fitting preceded by deconvolution analysis. Factor analysis revealed two statistically significant and physiologically meaningful kinetic patterns: one for specific and another for nonspecific binding of the radioligand. From these two factors a compartment model containing two tissue compartments (one for specific binding and another for nonspecific binding and free ligand) was constructed. The two‐compartment model was also supported by the impulse response function, which was obtained by deconvolution and showed two components. The factor image constructed from factor two demonstrated a distribution pattern characteristic for brain regions rich (frontal, parietal, and temporal lobes) or poor (occipital lobe and cerebellum) in H1 receptors. Blockade of H1 receptors with unlabeled pyrilamine, diphenhydramine, or hydroxyzine caused a significant reduction of this factor. Blockade produced no significant changes in factor one representing nonspecific binding.

We conclude that the kinetics of [11C]pyrilamine in the brain can be described by two tissue compartments, one related to the distribution of the H1 receptors. Factor analysis of dynamic studies can be used to locally separate these two compartments, for identification of regions rich and poor in H1 receptors and for noninvasive quantitative investigation of the effects of H1 receptor blockers such as pyrilamine, diphenhydramine, or hydroxyzine. © 1993 Wiley‐Liss. Inc.
MK‐801 Disrupts the expression but not the development of bromocriptine sensitization: A state‐dependency interpretation
Authors: Carlezon William A. , Mendrek Adrianna , Wise Roy A.
Published: January 2005

Repeated administration of the D2‐type agonist bromocriptine (5.0 mg/ kg, IP) caused progressive increases in the locomotor‐stimulating effects of the drug in rats. Similar progressive increases in locomotor activity were observed in rats that received repeated coadministration of the NMDA receptor antagonist MK‐801 (0.25 mg/ kg, IP) plus bromocriptine. However, when rats previously treated with the combination of drugs received either bromocriptine or MK‐801 alone, their levels of activity were comparable to those of rats having no prior experience with either drug. A second group of rats was sensitized to the effects of bromocriptine alone; no evidence of bromocriptine sensitization was seen when MK‐801 was subsequently coadministered with bromocriptine. Thus, either the presence or the absence of MK‐801 could—depending upon the conditions of previous drug treatment—block the expression of bromocriptine sensitization. When a third group of rats was sensitized to the combination of MK‐801 plus bromocriptine and subsequently tested following 2 or 6 drug‐free weeks, evidence of sensitized responses was still present. Thus, at the very least, blockade of NMDA receptors with MK‐801 fails to compromise the cellular changes associated with sensitization to the repeated combination of MK‐801 plus bromocriptine. Bromocriptine sensitization may prove to be unique in this regard, but the present findings suggest a control condition that should be carefully explored in studies of the effects of MK‐801 on sensitization involving other stimulant drugs. © 1995 Wiley‐Liss, Inc.
Sensitization to cocaine and dopamine autoreceptor subsensitivity in the nucleus accumbens
Authors: Pierce R. Christopher , Duffy Patricia , Kalivas Peter W.
Published: January 2005

It has been suggested that dopamine autoreceptor subsensitivity may play a role in cocaine‐induced behavioral sensitization. In order to evaluate this hypothesis, we administered cocaine to rats daily (15 mg/kg ip × 2 days, 30 mg/kg ip × 5 days) and then monitored nucleus accumbens dopamine during the local administration (through the dialysis probe) of the D2/D3 agonist, quinpirole (0, 0.1, 1, and 10 μM). Our results indicate that, relative to saline‐pretreated control animals, repeated cocaine administration impaired the ability of quinpirole to decrease extracellular dopamine 1–2 days after the last drug injection. However, quinpirole was equipotent at reducing accumbal dopamine in cocaine‐ and saline‐treated animals following a 21–22 day withdrawal period. These results demonstrate that repeated cocaine produces a short duration functional tolerance in the capacity of autoreceptor stimulation to inhibit accumbal dopamine release. © 1995 Wiley‐Liss, Inc.
Positron emission tomography imaging of serotonin transporters in the human brain using [11C](+)McN5652
Authors: Szabo Zsolt , Kao Pan Fu , Scheffel Ursula , Suehiro Makiko , Mathews William B. , Ravert Hayden T. , Musachio John L. , Marenco Stefano , Kim Sang Eun , Ricaurte George A. , Wong Dean F. , Wagner Henry N. , Dannals Robert F.
Published: January 2005

This paper presents the first Positron Emission Tomography (PET) images of the serotonin (5‐hydroxytryptamine, 5‐HT) transporter in the living human brain. PET imaging was performed in three healthy subjects after administration of [11C](+)McN5652 (the (+) enantiomer of trans‐l,2,3,5,6,10β‐hexahydro‐6‐[4‐(methylthio) phenyl]pyrrolo‐[2,1‐a] ‐isoquinoline), a radioligand previously shown to selectively label the 5‐HT transporter in vivo in the mammalian (mouse and baboon) brain. To demonstrate the specificity of [11C](+)McN5652 binding, additional images were obtained in the same subjects after injection of [11C](−)McN5652, the pharmacologically inactive enantiomer, and, in two of the subjects, with [11C](+)McN5652 after pretreatment with the 5‐HT uptake site blocker fluoxetine.

Highest accumulation of [11C](+)McN5652 was observed in the midbrain, putamen, caudate nucleus, hypothalamus, and thalamus, regions known to contain high densities of 5‐HT transporters. In these areas [11C](+)McN5652 concentrations rose steadily over 120 min. In contrast, with [11C](−)McN5652 and when the [11C](+)McN5652 binding was inhibited with fluoxetine, radioactivity concentrations declined after reaching a maximum (at 20 to 30 min). Inhibition studies with fluoxetine suggest that only with [11C](+)McN5652, there is specific binding. In the cerebellum, a region relatively void of 5‐HT transporters, both [11C](+)McN5652 with and without fluoxetine block and [11C](−)McN5652 were released at approximately the same rate.

The results of the studies indicate that [11C](+)McN5652 labels 5‐HT transporter sites in the human brain. Quantitative PET imaging studies with this new tracer should provide valuable information on the status of these sites in health and disease. © 1995 Wiley‐Liss, Inc.
Ultrastructural correlates of haloperidol‐induced oral dyskinesias in rat striatum
Authors: Roberts Rosalinda C. , Gaither Lorie A. , Gao Xue‐Min , Kashyap Smriti M. , Tamminga Carol A.
Published: January 2005

Neuroleptics given chronically to rats induce behavioral sequelae which mimic tardive dyskinesia in some respects. The intent of this study was to investigate the ultrastructural correlates of oral dyskinesias (vacuous chewing movements [VCMs]), induced by chronic haloperidol treatment. After 6 months of treatment, rats were divided into low or high VCM groups. Rats in the high VCM group were either sacrificed on drug or were withdrawn from drug for 4 weeks. Ultrastructural analyses of the striatum indicated that synaptic density: (1) was significantly decreased in both the low and high VCM groups compared to normal controls; (2) was more profoundly decreased in the high VCM group as compared to the low VCM group; and (3) recovered to normal following drug withdrawal. Compared to controls, the density of asymmetric synapses was reduced by a similar magnitude in both the low and high VCM groups, suggesting that this change is a result of haloperidol treatment and independent of VCMs. Conversely, the density of symmetric synapses was reduced compared to normal, only in the high VCM group, suggesting that this change is specifically related to the expression of VCMs. In addition, mitochondria1 profiles were hypertrophied and less frequent in the high VCM group in comparison to controls; size, but not number, recovered following drug withdrawal. These results identify distinct ultrastructural correlates of chronic haloperidol treatment that are unique to rats that develop VCMs and suggest that these ultrastructural features may play a role in the pathophysiology of oral dyskinesias in rats. © 1995 Wiley‐Liss, Inc.
Die Gravimetrische Bestimmung des Phosphorwasserstoffes und ein neuer Apparat zur Gasanalyse
Authors: Moser L. , Brukl A.
Published: January 2005

Es wurde gezeigt, daß eine wäßrige Lösung von Jodsäure, Phosphorwasserstoff quantitativ zu Phosphorsäure oxydiert, die nach Entfernung des Überschusses der Jodsäure als Magnesium‐pyrophosphat bestimmt wird. Die neue Methode darf als gleichwertig mit den besten bekannten Methoden zur gravimetrischen Bestimmung des Phosphins angesehen werden.
Über die Wertigkeit des Wolframs und Molybdäns in ihren komplexen Octocyaniden
Authors: Collenberg Oscar Olsson
Published: January 2005

Es wurden die früheren Wertigkeitsbestimmungen bei den Molybdän‐ und Wolframcyaniden vom Typus M4R(CN)8 kritisch besprochen und dabei erwiesen, daß sie zu irrigen Schlüssen über die Valenzstufe des Zentralatoms geführt haben.
Über neue jodometrische Methoden, die auf der Bildung und Messung von Jodcyanid beruhen. I
Authors: Lang Rudolf
Published: January 2005

Es wurden volumetrische Methoden zur Bestimmung von Jodid angegeben, die darauf beruhen, daß Jodid in salz‐ oder schwefelsaurer Lösung bei Anwesenheit von Cyanwasserstoff durch oxydierende Maßflüssigkeiten (Jodat und Permanganat) zu Jodcyanid oxydiert wird, wobei das Verschwinden der Jodstärkereaktion den Endpunkt anzeigt. An diese Oxydation kann unmittelbar die Messung des gebildeten Jodcyanids mit Thiosulfat angeschlossen werden, so daß jede Bestimmung in doppelter Art durchführbar ist. Auch Nitrit kann als Oxydationsmittel angewendet werden; die Bestimmung geschieht dann mit Thiosulfat allein, nachdem der Überschuß des Nitrits mit Harnstoff zerstört wurde.
Über Einige neue maßanalytische Methoden. (Sulfat‐, Blei‐, Säure‐ und Ammoniakbestimmung.)
Authors: Jellinek Karl , Ens H.
Published: January 2005

1. Es wurde eine Sulfatbestimmung ausgearbeitet, bei welcher das Sulfat mit überschüssigem Ba(NO3)2 dann das Ba++ mit überschüssigem K2CrO4 gefällt wird und mit Ba(NO3)2‐Lösung auf Verschwinden der gelben Färbung der Lösung titriert wird.
Über Kristallisierte Natriumsilikate
Authors: Erdenbrecher Alfred Heinrich
Published: January 2005

Durch vorliegende Arbeit konnte die Existenz von Na2SiO3·9H2O, Na2SiO3·6H2O, Na2SiO3·4H2O nachgewiesen werden Na2SiO3·14H2O ist wahrscheinlich.
Beiträge zur Chemie der Platinmetalle. III. Darstellung des Ruthenpentoxyds
Authors: Remy Heinrich
Published: January 2005

Es wurde festgestellt, daß die freiwillige Oxydation des Ruthenohydroxyds – das wegen seiner für die Isolierung sehr ungünstigen Eigenschaften bis jetzt noch nicht in zur Analyse brauchbarem Zustande abgeschieden werden konnte – durch Luftsauerstoff zum Pentoxyd des Rutheniums führt. Ebenso wurde Ruthenpentoxyd als Zerfallsprodukt von längere Zeit im zugeschmolzenen Glasröhrchen aufbewahrtem Tetroxyd erhalten. In jedem Falle erwies sich das Produkt als wasserhaltig; wenn es aus alkalischer Lösung gefällt war, enthielt es zudem auch Alkali. Ob das Pentoxyd mit Wasser oder mit Alkali in einfachen stöchimetrischen Verhältnissen zu Verbindungen zusammentritt, kann noch nicht gesagt werden.
Die elektrometrische Bestimmung des Mangans
Authors: Müller Erich , Wahle Otto
Published: January 2005

Es werden zwei Methoden mitgeteilt zur elektrometrischen Bestimmung des Mangans in Mangan(2)salzlösungen mit Permanganat, die eine bei Gegenwart von Zinksalz oder Kaliumnitrat, die andere bei Gegenwart von Fluorion. Beide stimmen mit der Volhardschen gut überein.
Atomanordnung und Valenz in Kristallen
Authors: Beckenkamp J.
Published: January 2005

Es scheint die Valenzverkettung noch die weitere Folge zu haben, daß sich je zwei Atome in den vom Atomkern ausgesandten Strahlen im Laufe größerer Zeiträume einander anpassen, d. h. daß durch Aufnahme oder Abstoßung von Uratomen in den bzw. aus dem Kern die Schwingungen in ein genaueres Resonanzverhältnis gebracht werden.
Notiz zu der Abhandlung. Zur Kenntnis amphoterer Elemente
Authors: Kasaelxowsky J.
Published: January 2005

Die Abweichung der benutzten 0εh‐Werte (–0,836 bzw. +0,567) von den früher2) gegebenen (–0,818 bzw. + 0,549), rührt davon her, daß einerseits auf Grammformelgewichte umgerechnet wurde und andererseits versucht wurde, die Dissoziationsgrade zu schätzen. Die Anwendung zweier empirischer Regeln3) ergab fur eine 0,005 n K2Te2‐Lösung in 1 n KOH4), γ = 0,56 und für 0,01 n TeCL4 iu 2,5 n HCl5) γ = 0,25; die entsprechenden Korrekturen betragen −0,009 bzw. + 0,009 Volt.
Über die Bildung von Perjodat bei der Einwirkung von Permanganat auf verschiedene Verbindungen des Jods
Authors: Lang Rudolf
Published: January 2005

Zum Schluß mag noch erwähnt werden, daß eine praktische Anwendung der Reaktion zwischen Permanganat und Jodat zu exakten analytischen Zwecken kaum möglich sein wird, wie näher nicht erst begründet zu werden braucht.
Cer, Cermischmetalle und Wasserstoff
Authors: Sieverts A. , Müller‐Goldegg G.
Published: January 2005

1. Die untersuchten Metalle waren

95%, iges Cer,

cerreiches Mischmetall (54% Ce),

lanthanreiches Mischmetall (84% La usw., 10% Ce),

eine Cer‐Manganlegierung (mit etwa 8% Mn).
Über die Einwirkung von Wasserstoffsuperoxyd auf Fällungen von Zinksalzen mit Natriummetasilikat
Authors: Erdenbrecher A. H.
Published: January 2005

Durch vorliegende Arbeit wird dargetan, daß Zinksalz‐Natrium‐Silikatfällungen bei Gegenwart von Wasserstoffsuperoxyd zu sauerstoffhaltigen Produkten führen können. Der Sauerstoffgehalt schwankt je nach der Konzentration des H2O2. In unseren Fällen beträgt er 2,3–7,9%. Diese Substanzen sind nicht als definierte Verbindungen aufzufassen, sondern sind in allen Fällen Gemische von Zinkperoxyd und Kieselsäure, gegebenenfalls verunreinigt mit Zinksilikat und den übrigen Reaktionsprodukten; Fällungen mit Natriumcarbonat führen zu Zinkperoxyden mit einem maximalen Sauerstoffgehalt von 12,10%0. Einmal gebildetes Zinksilikat wird durch Wasserstoffsuperoxyd nicht mehr angegriffen. Wir haben daher in dem Wasserstoffperoxyd ein Mittel in der Hand, Zinkoxyd neben Zinksilikat nachzuweisen, da nur ersteres Wasserstoffsuperoxyd anlagert.
Beiträge zur Kenntnis der Überspannungserscheinungen. II. Über den Zusammenhang zwischen der Überspannung des Wasserstoffs an reinen Metallen und gewissen Eigenschaften der Metalle
Authors: Thiel A. , Hammerschmidt W.
Published: January 2005

1. Es wurde die Überspannung des Wasserstoffs an einer größeren Zahl von Metallen nach der verbesserten Bläschenmethode nen bestimmt.
Über die Photochemische Zersetzung des Chlorsilbers
Authors: Schwarz Robert , Gross Peter
Published: January 2005

Es wurde die photochemische Zersetzung des Chlorsilbers im panchromatischen Lichte untersucht, wobei als Meßmethode die Bestimmung des bei der Zersetzung freiwerdenden Chlors zugrunde gelegt wurde. Hierbei ergaben sich folgende Resultate:

Die photochemische Zersetzung wird durch den Feuchtigkeitsgehalt beeinflußt. Feuchtes Chlorsilber wird stärker als trocknes zersetzt.

Von wesentlichem Einfluß auf die Zersetzlichkeit sind die Fällungsbedingungen, von denen die Art der adsorbierten Ionen abhängt. Es wird das verschiedene Verhalten von „Chlorkörper”︁ festgestellt.

Es werden für die verschiedenen Zustandsformen photochemische Dissoziationskurven aufgestellt, die über den Zusammenhang zwischen Lichtintensität und photochemischer Zersetzung Aufschluß geben.
Über die Thermische Dissoziation des Mangan‐ und Magnesiumcarbonats
Authors: Manchot W. , Lorenz L.
Published: January 2005

1. Gefälltes Mangancarbonat ist stets wasserhaltig und ohne fast vollständige Zersetzung nicht zu entwässern.
Über Adsorption. Nr. 3. Über den Umschlag eines Holzkohleabsorbers bei der Adsorption von Kohlendioxyd und Wasserstoff
Authors: Lorenz Richard , Wiedbrauck E.
Published: January 2005

1. Es wird ein Gemisch von Kohlendioxyd und Wasserstoff der Adsorption an Holzkohle unterworfen und die Gleichgewichtseinstellung beobachtet.
Über die innere Reibung geschmolzener Metalle und Legierungen. I. Das Meßverfahren und die innere Reibung von pb‐Bi‐Legierungen
Authors: Sauerwald F.
Published: January 2005

Es wurde eine Methode zur Messung der inneren Reibung für Metalle und Legierungen bei höherer Temperatur ausgearbeitet. Messungen an Quecksilber ergaben Übereinstimmung mit bekannten Werten. Messungen an Blei‐Wismut‐Legierungen ergaben, daß ihre Viskosität kleiner als nach der Mischungsregel berechenbar ist, daß die Abhängigkeit von der Konzentration im eutektischen Bereich eine einfache ist und kein Maximum oder Minimum vorhanden ist.
Zur Kenntnis der Doppelselenide
Authors: Meyer Julius , Bratke Herbert
Published: January 2005

1. Von den in der Natur vorkommenden selenhaltigen Mineralien, in denen das Selen an zwei verschiedene Metalle gebunden ist, kann bisher nur der Eukairit als wirkliches Doppelselenid von der Formel Ag2Se · Cu2See betrachtet werden, während der Umangit, Zorgit, Lerbachit und der Crookeist als Gemenge mehrerer Selenide aufzufassen sind.
Über Freien und perlitischen Zementit
Authors: Maurer E. , Stäblein F.
Published: January 2005

1. Die Widerstandserhöhung geglühten Stahls in Abhängigkeit vom C‐Gehalt wurde ermittelt und zwar

für lamellaren,

für körnigen Zustand des Perlits.
Über Aluminium‐Chlor‐Schwefelverbindungen
Authors: Ruff Otto , Golla Hans
Published: January 2005

Die Reaktion zwischen Aluminiumchlorid oder Aluminium mit den Schwefelchloriden und Schwefel ist untersucht und eine überraschend große Zahl verschiedenartiger Reaktionsprodukte festgestellt worden.
Die Anwendung von flüssigem Amalgam in der volumetrischen Analyse. I. Verwendung von Zink‐ und Wismutamalgam
Authors: Someya Kinichi
Published: January 2005

Flüssiges Wismutamalgam reduziert Vanadinsäure zu vierwertigem Vanadium, Ferrisalze zu Ferrosalzen, Titansäure zu Titanoverbindungen und Molybdänsäure zu fünfwertigem Molybdän unter geeigneten Bedingungen.
Über Darstellung von reinem Uran
Authors: Jander Wilhelm
Published: January 2005

Es werden Versuche beschrieben, die die Darstellung von Uranmetall durch Reduktion von Urandioxyd mittels Calcium bezwecken.
Über das Siloxen und seine Derivate
Authors: Kautsky H. , Herzberg G.
Published: January 2005

1. Für das Siloxen wurde auf Grund seiner Eigenschaften, besonders seines Verhaltens gegen Halogene, folgende Strukturformel aufgestellt: magnified image

Es wird auch die abgekürzte Formel verwendet: magnified image
Über die Dissoziation mehratomiger Salze
Authors: Sasaki Nobuji
Published: January 2005

Es wurde am Beispiel von Ferrichloridlösung mathematisch untersucht, wie die Konzentrationen des Moleküls und seiner Dissoziationsprodukte aller Stufen von der Gesamt‐, von der Kationen‐ und von der Anionenkonzentration abhängen.