bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pharmacological characterization of a serotonin receptor involved in an early embryonic behavior of Helisoma trivolvis
Authors: Goldberg Jeffrey L. , Koehncke Niels K. , Christopher Kim J. , Neumann C. , Diefenbach Thomas J. 
Published: January 2005

AbstractIn contrast to the abundance of information on the many physiological and developmental actions of serotonin in molluscan nervous systems, comparatively little is known about the serotonin receptors involved in these responses. Embryos of the pulmonate gastropod, Helisoma trivolvis, display a cilia‐driven rotational behavior that is regulated by endogenous serotonin. In the present study, two functional assays were used to determine some of the pharmacological properties of the receptors that mediate the cilio‐excitatory action of serotonin. Timelaspe video microscopy was used to measure whole embryo rotation rat and cilia beat frequency in isolated cells. In dose‐response experiments, serotonin was approximately 10 times more potent in stimulating cilia beat frequency over embryo rotation. In rotation experiments, 5‐carboxyamidotryptamine and methysergide had effective agonist activity in dose ranges similar to that of serotonin (1 to 100 μM). In contrast, 8‐hydroxydiproylaminotetralin HBr (8‐OH‐DPAT) displayed agonist activity of lower potency and effectiveness. Several compounds displayed antagonist activity in the 1 to 100 μM dose range, including mianserin, spiperone, ritanserin, 1‐(1‐naphthyl) piperazine, and Propranolol. α‐Methylserotonin had mixed agonist–antagonist activity, and metoclopramide, MDL‐72222, and ketanserin were inactive. Experiments on isolated cells suggested that the extremely effective antagonism displayed by mianserin in the embryo rotation assay was due to its specific activity at ciliary serotonin receptors. These results implicate the presence of a novel serotonin receptor on embryonic ciliated cells that is pharmacologically distinct from those previously characterized in vertebrate or invertebrate systems. 1994 John Wiley & Sons, Inc.
Gap‐43 immunoreactivity and axon regeneration in retinal ganglion cells of the rat
Authors: Schaden H. , Stuermer C. A. O. , Bähr M. 
Published: January 2005

AbstractRetinal ganglion cells (RGCs) in rats were retrogradely labeled with the fluorescent tracer Fluorogold (FG) and subjected to GAP‐43 and c‐JUN immunocytochemistry to identify those RGSs that are capable of regenerating an axon. After optic nerve section (ONS) and simultaneous application of FG to the nerve stump (group 1 experiments), GAP‐43 immunoreactive RGCs (between 2 and 21 days after ONS) always represented a subfraction of both FG‐labeled (i.e., surviving) RGCs and RGCs exhibiting c‐JUN. GAP‐43 immunoreactive RGCs represented 22% of RGCs normally present in rat retinae and 25% of surviving RGCs at 5 days after ONS but were reduced to 2% and 1%, which is 6% and 5% of survivors at 14 and 21 days, respectively. In animals that received a peripheral nerve (PN) graft after ONS (group 2 experiments), RGCs with regenerating axons were identified by FG application to the graft at 14 and 21 days. When examined at 21 and 28 days, all FG‐labeled RGCs exhibited GAP‐43 immunoreactivity, and FG/GAP‐43‐labeled RGCs were 3% and 2% of those resent in normal rat retinae. In relation to surviving. RGCs GAP‐43 immunoreactive RGCs represented 10% at both time points. FG‐/GAP‐43 labeled RGCs also exhibited c‐JUN, but c‐JUN immunoreactive RGCs were at both time points at least twice as numerous a FG‐/GAP‐43‐labeled RGCs. These data suggest that regenerating axons in PN grafts derive specifically from GAP‐43 reexpressing RGCs. Appearance of GAP‐43 immunoreactivity may therefore identify those RGCs that are capable of axonal regeneration or sprouting. 1994 John Wiley & Sons, Inc.
Spontaneous bursting and long‐lived local correlation in normal and denervated tectum of goldfish
Authors: Lyckman Alvin W. , Meyer Ronald L. 
Published: January 2005

AbstractThe formation of fine retinotopic order by growing optic fibers in the goldfish is thought to be mediated by the correlated firing of optic fibers from neighboring retinal ganglion cells. Although the activity of the tectal cells must also be important for this activity‐dependent refinement, few studies have analyzed the pattern and local correlation of the intrinsic activity of tectal neurons and the effect of denervation on this activity. To address this issue, spontaneous (nonoptic driven) activity was analyzed and cross‐correlograms were computed between individual tectal neurons using single and double electrode extracellular recordings. Recordings were made in normally innervated tectum in which the contribution of optic activity was eliminated by short‐term intraocular blockade with tetrodotoxin and in denervated tecta in which the optic nerve had been severed several weeks prior. Several observations were relevant to activitydependent refinement: First, coupling between neighboring tectal cells is weak. Second, the time duration for local correlation is relatively long, as long as 200 ms. Third, tectal neurons exhibit spontaneous bursting. Fourth, denervation increased the level of spontaneous activity in the tectum. The increased spontaneous activity and bursting following denervation implies that tectal neurons are more excitable when optic fibers are beginning to reinnervate the tectum. This could make it possible for optic fibers to drive tectal neurons at a time when their input to individual neurons is severely weakened by a lack of spatial convergence. The weak coupling between tectal cells and the consequent long‐time constant for correlated activity implies a constraint on the duration of correlated retinal activity that is used for activitydependent refinement. Since optic fibers likely need to detect the postsynaptic activity of a local group of tectal neurons, rather than that of a single neuron, the long tectal time constant means that retinal activity need not be correlated with precision much better than 200 ms because the postsynaptic circuitry cannot generate shorter correlations. © 1995 John Wiley & Sons, Inc.
Lectin binding distinguishes between neuroendocrine and neuronal derivatives of the sympathoadrenal neural crest
Authors: Katz David M. , White Melissa E. , Hall Alison K. 
Published: January 2005

AbstractLectin cytochemistry was used to identify surface epitopes selectively expressed by chromaffin cell chemoreceptors (glomus cells) in the rat carotid body. Unexpectedly, these studies revealed that binding sites for peanut agglutinin (PNA; Arachis hypogea) were highly expressed by all neuroendocrine derivatives of the sympathoadrenal neural crest, including glomus cells, small, intensely fluorescent cells, and adrenal chromaffin cells in situ. In contrast, principal sympathetic neurons did not express PNA receptors. PNA binding was inhibited by 2% galactose. To determine whether expression of PNA receptors was selectively induced by neuroendocrine differentiation of sympathoadrenal precursors, we compared PNA labeling of embryonic sympathoblasts in the presence of either nerve growth factor (NGF) or the synthetic glucocorticoid dexamethasone (DEX). Dex‐treated cells, which expressed several neuroendocrine traits, bound PNA, whereas NGF‐treated neuronal derivatives did not. In addition, to examine whether expression of existing PNA receptors was down‐regulated by neuronal differentiation of chromaffin cells, we compared labeling of PC12 cells, which normally bind PNA, in the presence and absence of NGF. Although PC12 cells acquired characteristic neuronal morphologies in the presence of NGF, they did not lose PNA labeling, even after 8 days of NGF treatment. These findings indicate that neuronal and neuroendocrine derivatives of the sympathoadrenal lineage can be distinguished by differential expression of carbohydrate epitopes and suggest that PNA receptors are induced by neuroendocrine differentiation. © 1995 John Wiley & Sons, Inc.
Red‐light‐induced suppression of melatonin synthesis is mediated by N‐methyl‐D‐aspartate receptor activation in retinally normal and retinally degenerate rats
Authors: Poeggeler Burkhard H. , Barlow‐Walden Lornell R. , Reiter Russel J. , Saarela Seppo , Menendez‐Pelaez Armando , Yaga Ken , Manchester Lucien C. , Chen Li‐Dun 
Published: January 2005

AbstractPineal gland N‐acetyltransferase (NAT) activity and pineal and serum levels of melatonin declined linearly in albino rats acutely exposed to different intensities of red light (600 nm or higher; low, 140μ W/cm2; moderate, 690 μW/Cm2; high, 1200 μW/Cm2) during the middle of the night. The high intensity red light was as effective as white light (780 μW/cm2) in suppressing NAT activity and pineal and circulating melatonin. Red‐light‐inhibited nighttime NAT activity and suppressed nocturnal melatonin levels in both retinally degenerate and normal rats. Pretreatment with the N‐methyl‐D‐aspartate (NMDA) receptor antagonist MK‐801 (10 mg/kg intraperitoneally) completely prevented the red‐light‐induced inhibition of nighttime melatonin synthesis. Magnesium chloride (300 mg/kg intraperitoneally) reduced the inhibitory effects of low and moderate intensities of red light but was ineffective when high red‐light intensity was used. However, both agents failed to antagonize the suppression of nighttime melatonin synthesis elicted by the exposure to white light. Since retinally degenerate and retinally normal animals respond in the same way to both red‐light and pharmacological intervention with the NMDA receptor blocker MK‐801, the findings indicate that the activation of central hypothalamic NMDA receptors might mediate the photic inhibition of nocturnal melatonin synthesis in the pineal gland elicited by the exposure to red light at night. Red‐light‐induced suppression of nocturnal melatonin synthesis possibly can be used to investigate the biochemical mechanisms by which light entrains melatonin synthesis and to study the pharmacological and physiological effects of endogenous and synthetic agents that antagonize the NMDA receptor response. © 1995 John Wiley & Sons, Inc.
Transforming growth factor‐β‐3 is mitogenic for rat retinal progenitor cells in vitro
Authors: Anchan Raymond M. , Reh Thomas A. 
Published: January 2005

AbstractRecent data indicate that the process of neurogenesis in the mammalian central nervous system (CNS) may be regulated by peptide growth factors, such as epidermal growth factor, transforming growth factor‐alpha, and acidic or basic fibroblast growth factor. We have investigated whether members of the transforming growth factor‐beta (TGFβ) family also play a role in this process and have found that TGFβ‐3 is mitogenic for embryonic rat retinal cells in vitro. We also show that TGFβ‐3 stimulates production of retinal amacrine cells while photoreceptor production remains unchanged. These data demonstrate that TGFβ‐3 can regulate cell proliferation in the CNS during development and can also influence commitment or differentiation, or both, of neural progenitor cells to particular retinal fates. © 1995 John Wiley & Sons, Inc.
White‐throated sparrow morphs that differ in song production rate also differ in the anatomy of some song‐related brain areas
Authors: DeVoogd Timothy J. , Houtman Anne M. , Falls J. Bruce 
Published: January 2005

AbstractWhite‐throated sparrows are unusual among songbirds in that they occur in two color morphs, white‐striped and tan‐striped, determined by a chromosomal inversion and maintained by negative assortative mating. These differ in several reproductive behaviors, including amount of singing: white‐striped males sing frequently, tan‐striped females never sing, and tan‐striped males and white‐striped females sing an intermediate amount. The present study measures the volumes of several nuclei in the avian song system and relates these to color morph and to sex. We find that robustus archistristalis and the tracheosyringeal part of the hypoglossal nucleus, nuclei closely involved in song production, are larger in white‐striped than in tan‐striped birds. We also find morph differences for nuclei in the rostal division of the song system, nuclei believed to be less directly involved in song production. We find sex differences throughout the song system as has been reported in other songbirds. Relationships between structure and function in the song system are discussed. © 1995 John Wiley & Sons, Inc.
Role of neuropeptide Y (NPY) in cardiovascular responses to stress
Authors: Zukowska‐Grojec Z. , Vaz A. C. 
Published: January 2005

AbstractNeuropeptide Y (NPY), a putative sympathetic neurotransmitter and neuromodulator, is released during sympathetic nerve stimulation and causes vasoconstriction and cardiodepression. Whether the release of NPY contributes to stress‐induced cardiovascular responses was assessed by studying i/ plasma levels of circulating NPY‐immunoreactivity (NPY‐ir) during various stress paradigms and ii/ mechanisms of action of NPY in the cardiovascular system of the rat. Plasma NPY‐ir was increased by all stress situations, such as transfer to a new environment (by 52%), exposure to cold water (40C) (by 117%) and hemorrhage (4 ml/300 g body weight) (by 231%). The cold water, stressinduced, maximal increase in circulating plasma NPY‐ir was delayed in relation to the peak pressor response by 10–20 min. Administration of NPY caused dose‐dependent pressor responses that were greater in pithed rats ‐ which have all centrally mediated circulatory reflexes removed ‐ than in conscious rats. Infusion of a low pressor (8.5 ± 1.5 mm Hg) dose of norepinephrine into conscious rats potentiated NPY‐mediated pressor responses 2‐fold and also tended to increase bradycardic effect of a higher dose of NPY (by 19%). Thus hypertensive and bradycardic actions of NPY appear to depend on the level of adrenergic activity and on the interactions at the level of vascular smooth muscle, heart, and baroreceptor reflexes. During a hyperadrenergic state such as stress, cardiovascular effects of NPY may be greatly accentuated. NPY may enhance and prolong the stressinduced hypertensive responses while antagonizing adrenergic cardiostimulation.
Ultrastructural characterization and GAD Co‐localization of somatostatin‐like immunoreactive neurons in CA1 of rabbit hippocampus
Authors: Kunkel Dennis D. , Schwartzkroin Philip A. 
Published: January 2005

AbstractImmunocytochemical techniques have been used to identify a striking interneuronal population which is immunoreactive for the peptide, somatostatin. The cell population, which is seen most densely in stratum oriens and at the oriens/alveus border of the CA1 region of rabbit hippocampus, was characterized in light and electron microscopic observations. The cells have dendrites which extend parallel to and into the alveus, with occasional processes ascending through stratum pyramidale toward the hippocampal fissure. The dendrites receive numerous synaptic contacts directly onto aspinous dendritic shafts. Axon collaterals ramify profusely within the pyramidale region, and among the proximal apical and basal pyramidal cell dendrites in areas of stratum radiatum and stratum oriens. Somatostatin‐like immunoreactive terminals make synaptic contact, primarily of the symmetric type, with the somata and proximal dendrites of pyramidal neurons. Somatostatin‐like neurons are found at approximately equal density in the hippocampus of immature (8 days postnatal) and mature (30 days postnatal) rabbit. Double‐labelling techniques, to identify both somatostatin‐like and glutamic acid decarboxylase (GAD) immunoreactive neurons, demonstrated that a large proportion of the somatostatin neurons were also GABAergic.
Polyamines regulate glycine interaction with the N‐methyl‐D‐aspartate receptor
Authors: Ransom Richard W. , Deschenes Nancy L. 
Published: January 2005

Abstract[3H]Glycine blinding studies have been performed to further characterize polyamine interactions with the rat brain N‐methyl‐D‐asparate (NMDA) receptor. Strychnine‐insensitive [3H]glycine binding to washed cortical membranes was enhanced by spermine, spermidine, and hirudonin. Spermine stimulation of binding was additive with that produced by the NMDA receptor agonist L‐glutamate. A high concentration of the L‐glutamate antagonist 2‐amino‐5‐phosphonovaleric acid reduced, but did not eliminate, spermine effects. Saturation experiments indicated that L‐glutamate and spermine enhancement of binding was due to an increase in [3H]glycine binding affinity. Kinetic studies showed that optimal concentrations of spermine and L‐glutamate reduced [3H]glycine association and dissociation rates by approximately fivefold and 30‐fold, respectively. In competition experiments, the presence of L‐glutamate and spermine had differential effects on the affinites of compounds that act as either agonists or antagonists at the glycine site of the NMDA receptor. The affinities of the agonists glycine, D‐serine, and Dalanine, were increased about fivefold, while antagonist (HA‐966, 7‐chlorokynurenic acid) inhibitory potencies were unchanged. These data support our previous results showing that the NMDA receptor possesses a novel polyamine recognition site and demonstrate that these compounds directly modulate glycine's interactions with the receptor complex.
Dopamine neuron ontogeny: Electrophysiological Studies
Authors: Pitts David K. , Freeman Arthur S. , Chiodo Louis A. 
Published: January 2005

AbstractThe ontogeny of nigrostriatal dopamine (NSDA) neurons was examined with single‐unit extracellular electrophsiological methods. The physiological and pharmacological characteristic of 2‐, 4‐, and 5‐week‐old rat pup NSDA neurons were compared with those of adults (8–10 weeks old). Although the basal discharge rate, conduction velocity, and firing pattern of NSDA neurons from 4‐and 5‐week‐old rats were similar to adults, the 2‐week‐old‐rats differed significantly in all three of these physiological significanlty lower in the 2‐week‐old pups relative to adult. In addition, there were significantly fewer bursting NSDA neurons in 2‐week‐olds than there were in adults. Two and 4‐week‐olds exhibited significantly lower sensitivity to cumulative intravenous doses of apomorphine. In contrast, the sensitivity to cumulative intravenous doses of quinpirole was found to be similar across all age groups. It is evident that the pharmacological and physiological properites of NSDA neurons are in a dynamic state of flux during postnatal development. These electrophysiological findings are discussed in the context of the perinatal development of midbrain DA systems.
Die Absorption von Stickstoff durch Calcium und seine Legierungen
Authors: Ruff Otto , Hartmann Hellmuth 
Published: January 2005

AbstractCalcium und calciumreiche Legierungen lassen sich in einem gegen die Luft abgeschlossenen Eisentiegel schmelzen. Den Abschluß erreicht man in befriedigender Weise, wenn man die Tiegelöffnung entweder autogen verschweißt oder durch eine Calcium‐chloridfluoridschmelze schließt, in welche der Tiegel mit der Öffnung nach unten eingesetzt wird.
Über die thermische Bildung von Ozon
Authors: Riesenfeld E. H. , Beja M. 
Published: January 2005

AbstractDie Bestimmung desthermischen Ozon‐Sauerstoff‐Gleichgewichts erfolgt am besten durch Untersuchung des bei der Explosion von Ozon‐Sauerstoffgemischen zurückbleibenden Gases. Dieses besteht bei der Explosion eines Gemisches, welches weniger als 37 Vol. ‐% Ozon enthält, aus reinem Sauerstoff. Die hierbei theoretisch erreichbare Maximaltemperatur beträgt 2130° abs. Die mit Sauerstoff im Gleichgewicht stehenden Ozonmengen liegen also bis zu dieser Temperatur unterhalb der analytischen Nachweisbarkeit, sie betragen weniger als 2 · 10−5 Vol.‐%. Bei der Explosion von 45 Vol. %, igem bis 94 Vol. %igem Ozon bleiben nach der Explosion unabhängig von der Anfangskonzentration des Ozons zwischen 2.10−6 und 1·10−6 Vol.‐% Ozon zurück. Bei diesen Explosionen können Maximaltemperaturen von 2385–3175° erreicht werden. Nach dem NERNST'schen Theorem ist 4,2 · 10−5 Vol.‐% die maximale Ozonkonzentration, dio sich thermisch ausgehend von reinem Ozon (0° und 760 mm), durch Explosion bei konstantem Volumen, bilden kann. Hierbei wird eine Temperatur von 3200° abs., also ein Druck von 17,6 Atm. erreicht.
Über die Absorptionsspektra von gefärbten Gläsern
Authors: Fedotieff P. P. , Lebedeff A. 
Published: January 2005

AbstractDie Versuche mit der Färbung der Gläser und die Untersuchung der Absorptionsspektra derselben führten zur Konstruktion der Absorptionskurven sowohl im sichtbaren wie auch zum Teil im ultravioletten Gebiete des Spektrums. Für das letzte dienten die photographischen Aufnahmen der Spektra. Die am besten gelungenen Photographien sind in den Figuren 8–27 wiedergegeben. In der beistehenden, auf diese Aufnahmen bezogene Tabelle sind angegeben: die Zusammensetzung des Glases, die färbende Substanz, der Abstand von der Lichtquelle in cm, die Dauer der Exposition und endlich die Dicke der Platten in mm.
Über Cupro‐cupri‐cyanid‐ammoniak‐Verbindungen
Authors: Benbath A. , Schröder W. 
Published: January 2005

AbstractDie Cupro‐cupricyanid‐ammoniakverbindungen wurden als zu zwei Reihen, nämlich der

und der

gehörig erkannt. Die Bedingungen, unter denen die Glieder der Reihen ineinander übergehen, wurden festgelegt.
Die Anwendung von flüssigem Amalgam in der volumetrischen Analyse. V. Bestimmung von Phosphorsäure durch Uranylacetat
Authors: Someya Kin'ichi 
Published: January 2005

AbstractEs wurde eine neue Methode für die Bestimmung von Phosphorsäure ausgearbeitet, indem das kristallinisch gefällte Uranylammoniumphosphat mit Salzsäure aufgenommen, mit Zink‐ oder Wismutamalgam reduziert und mit Kaliumbichromat titriert wird unter Anwendung von Diphenylamin als Indicator.
Serial follow‐up study of serum testosterone and antisperm antibodies in patients with non‐obstructive azoospermia after conventional or microdissection testicular sperm extraction
Authors: Komori K. , Tsujimura A. , Miura H. , Shin M. , Takada T. , Honda M. , Matsumiya K. , Fujioka H. 
Published: December 2004

SummaryTesticular sperm extraction (TESE) combined with intracytoplasmic sperm injection is becoming a first‐line treatment even for non‐obstructive azoospermia. The current focus of TESE is the identification of seminiferous tubules that contain spermatozoa and minimization of testicular damage. Although microdissection TESE has been introduced as a preferred procedure for sperm retrieval, no serial follow‐up studies of testicular damage have been reported. In the present study, we assayed serum testosterone concentrations and for the presence of antisperm antibodies (ASA) for 1 year after conventional multiple TESE or microdissection TESE and compared postoperative testicular damage between procedures. Thirteen patients who underwent conventional multiple TESE and 12 patients who underwent microdissection TESE were included in this study. Serum total and free testosterone concentrations were evaluated before operation and 1, 6 and 12 months after TESE. Serum ASA was also evaluated before and 12 months after TESE. Serum total and free testosterone concentrations in all patients in both groups showed no significant postoperative decrease. A comparison between the two groups of serum total and free testosterone concentrations showed no significant difference (total testosterone, p = 0.2477; free testosterone, p = 0.3098). No incidence of new ASA formation was identified in the present study. In conclusion, TESE procedures cause neither a decrease of serum testosterone nor formation of ASA. Serum testosterone concentration are similar between patients in the conventional multiple TESE and microdissection groups. Therefore, microdissection TESE is safe with respect to testicular damage, particularly for patients with hypogonadism.