bluuebunny/crossref_metadata_2025_split huggingface dataset:
Age‐Dependent Increase in Neuropeptide Y Gene Expression in Rat Adrenal Gland and Specific Brain Areas
Authors: Higuchi Hiroshi , Yokokawa Kiyoshi , Iwasa Atsushi , Yoshida Hiroshi , Miki Naomasa 
Published: October 2006

AbstractAge‐dependent changes in the expression of neuropeptide Y (NPY) peptides and prepro‐NPY mRNA (NPY mRNA) were studied in rat adrenal gland and brain areas by means of radioimmunoassay, immunohistochemistry, and northern blot analysis. In the adrenal gland, NPY immunoreactívity (NPY‐I) increased by 80‐fold, mainly in the chromaffin cells, during aging (from 7 to 33 weeks old). The increase in NPY‐I was accompanied by a concomitant increase in the content of NPY mRNA (800 bases in size, by 16‐fold) and putative NPY pre‐mRNA, a result suggesting that this increase results from that in NPY gene expression, probably at the level of transcription. In contrast, in some brain areas, such as striatum and medulla oblongata plus pons, NPY‐I decreased in an age‐dependent manner, whereas NPY mRNA abundances in these areas increased by twofold with age (from 7 to 33 weeks old). The opposite changes between NPY and NPY mRNA content in specific brain areas suggested the accelerated turnover/degradation of NPY peptide in the brain areas. Furthermore, β‐actin mRNA abundance did not change in rat adrenal gland and brain areas during aging. Thus, the characteristic age‐related increase in NPY gene expression in rat adrenal gland and some brain areas seems to be important for physiological regulation of some neuronal functions, such as blood pressure, in aged animals.
A Fast Axonally Transported Protein of the Frog Sciatic Sensory Axons Undergoes Similar Qualitative Changes During Regeneration In Vitro and In Vivo
Authors: Remgård Pär , Ekström Per A. R. , Edström Anders 
Published: October 2006

AbstractThe adult frog sciatic sensory neurons have been shown to regenerate in vitro. If a crush injury is made at the beginning of culture, regeneration starts after 3.4 days and proceeds at a rate of ∼0.8 mm/day for several days. Two‐dimensional gel electrophoresis was used to study the patterns of radiolabeled, fast axonally transported proteins during the first 7 days of regeneration. Interest was focused on one protein, referred to as rrp31 (regeneration‐related protein 31), which changed in apparent pl from 4.9 to 5.3 when the outgrowth of new fibers started. The change was noticeable 3 days after injury and became prominent during day 5 of culturing. By day 7 the pl changed again, this time toward the original value. The in vitro results were supported by experiments in vivo. In this case the change occurred earlier, with a peak only 3 days after injury, after which the pl decreased. If adenosine at 1 mM was included in the culturing medium, the outgrowth of sensory axons was inhibited in a nontoxic way, and the pl changes of rrp31 were prevented. The temporal nature of the pl changes suggests a role for rrp31 in the initiation of the regeneration process.
Solubilization, Characterization, and Partial Purification of α‐Amino‐3‐Hydroxy‐5‐Methyl‐4‐Isoxazolepropionic Acid‐, Quisqualate‐, Kainate‐Sensitive l‐Glutamate Binding Sites from Porcine Brain Synaptic Junctions
Authors: Chang Yen‐Chung , Lin Yih‐Hong , Lee Yun‐Huey , Leng Chih‐Hsiang 
Published: October 2006

Abstract l‐[3H]Glutamate binding sites were solubilized from porcine brain synaptic junctions by Triton X‐114 in the presence of KC1. The solubilized binding sites bound l‐[3H]glutamate reversibly with Kd and Bmax values of 1.48 ± 0.18 μM and 178.2 ± 15.9 pmol/mg of protein, respectively. These binding sites appeared to be integral membrane glycoproteins, with sugar moieties recognized by wheat germ agglutinin. A 49.3‐fold purification of these binding sites was achieved by Triton X‐114 solubilization, anion‐exchange chromatography, and affinity chromatography using wheat germ agglutinin‐Sepharose. The apparent molecular mass of the partially purified binding sites was 620 ± 50 kDa. l‐[3H]Glutamate bound to the solubilized preparation could be effectively displaced by agonists of non‐N‐methyl‐d‐as‐partate (NMDA) l‐glutamate receptors but not by NMDA or α‐amino‐4‐phosphonobutyrate. The rank order for the competitive ligands in displacing l‐[3H]glutamate was: quisqualate > α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid > l‐glutamate > kainate.
Rapid Internalization and Intracellular Metabolic Processing of Exogenous Ganglioside by Cerebellar Granule Cells Differentiated in Culture
Authors: Riboni Laura , Tettamanti Guido 
Published: October 2006

AbstractGanglioside GMl, tritiated at the level of the long chain base (sphingosine) ([Sph‐3H]GMl), sialic acid (N‐ace‐tylneuraminic acid) ([NeuAc‐3H]GMl), or terminal galactose ([Gal‐3H]GMl) was supplied to cerebellar granule cells differentiated in vitro, and its metabolic processing was followed with pulse time. Using [Sph‐3H]GM 1 and [NeuAc‐3H]GMl the formation of radioactive compounds of catabolic origin (GM2, GM3, lactosylceramide, glucosylceramide, and ceramide) started being detectable at 10–15 min of pulse, whereas compounds of biosynthetic origin (GD1a, GD1b, GT1b, O‐acetylated GT1b, sphingomyelin, and sialoglycoprotein) appeared after 15–30 min of pulse. Using [Gal‐3H]GM1 two radioactive substances were formed, GD1 a and GT1b, with the former (produced by direct sialosylation of GM1) appearing after 30 min of pulse and the latter (formed by bio‐synthetic recycling of released galactose) appearing after 2 h. The radioactivity linked to all metabolites increased with increasing pulse time until 4 h. The percentage of GM1 taken up and subjected to metabolic processing was found to increase from 1.8% after 10 min of pulse to 12.5% after 4 h. Cerebellar granule cells were able to release enzymes of lysosomal origin, β‐D‐N‐acetylhexosaminidase and β‐D‐galac‐tosidase, into the culture medium, with the release being markedly decreased by the absence in the medium of fetal calf serum, a condition that was used for studying exogenous GM1 uptake and metabolization. However, these enzymes exerted no activity at the pH of the culture medium, and no radioactive gangliosides, besides GM1, were detected in the culture medium during pulse. Addition of 50 μM chloroquine to granule cells during the pulse experiments with radioactive GM1 completely blocked the metabolic processing of exogenous GM1 with the exception of direct sialosylation, a result indicating the key role played by lysosomes in the process. The overall results show that cerebellar granule cells take up, internalize, and metabolize exogenous GM1 rapidly, with the lysosomes being involved immediately in degradation, and the biosynthetic apparatuses somewhat later in recycling metabolic intermediates. The hypothesis can be proposed that the ganglioside present in the membrane domain subjected to internalization is rapidly turned over.
Transient Expression of Opioid Receptors in Defined Regions of Developing Brain: Are Embryonic Receptors Selective?
Authors: Barg Jacob , Simantov Rabi 
Published: October 2006

AbstractThe developmental profile of opioid receptors was studied in rat and guinea pig striatum and hippocampus. The two brain regions show different receptor profiles during development, which are characteristic for each animal. Yet, both tissues and animal species share one common feature; the binding of the universal opioid ligand [3H]diprenorphine per milligram of protein is high at the early embryonic period, it decreases toward birth, and then gradually increases to the adult levels. This apparent transient expression of the receptors during the early developmental stage was manifested in the guinea pig as an actual decrease in the total receptor number. As an attempt to characterize the receptors involved in this process, the binding of the selective μ‐opioid ligand [3H]Tyr‐d‐Ala‐Gly‐MePhe‐NH(CH2)OH ([3H]DAGO) was studied in striatal membranes of young (P1) and adult (P60) rats. Competition between [3H]DAGO and the δ‐selective peptide Tyr‐d‐Pen‐GIy‐Phe‐d‐Pen (DPDPE) shows higher affinity of the S opioid to P1 membranes than to P60 membranes, though the number of δ receptors in P1 membranes is very small. This observation is in line with a previous study suggesting that opioid receptors in embryonic striatum and hippocampus are less selective to various opioids than those of adult brain. An additional difference between adult and embryonic tissue was observed on Scatchard analysis of [3H]DAGO binding; striatum P60 membranes exhibit one binding site with a KD of 0.8 ± 0.1 nM and Hill coefficient of 0.96, whereas striatum P1 membranes bind the peptide in an apparent cooperative fashion with an overall Hill coefficient of 1.30. The possibility that a cooperative binding pattern involves interactions of SH groups was tested with the sulfhydryl reducing agent dithiothreitol (DTT). Indeed, DTT‐treated membranes from adult rat striatum bind [3H]DAGO in a cooperative fashion (Hill coefficient, 1.32). The significance of a transient expression of apparently nonsetective opioid receptors in developing brain, and the possibility that receptors from embryonic and adult brain interact differently with one another or with other membrane constituents, such as G proteins and ion channels, is discussed.
Characterization of Rat ARPP‐21 mRNA: Sequence Analysis, Tissue Distribution, and Regulation
Authors: Ehrlich Michelle E. , Greengard Paul 
Published: October 2006

AbstractARPP‐21 (cyclic AMP‐regulated phosphoprotein; Mr= 21,000) is a cytosolic neuronal phosphoprotein that is highly enriched in the striatum and in other dopaminoceptive regions of the brain. The state of phosphorylation of ARPP‐21 is also regulated by vasoactive intestinal peptide in intact cells. We previously reported the sequence analysis of bovine ARPP‐21 cDNA and have now characterized rat ARPP‐21 cDNA to study further the molecular biology of this protein. The sequence of the coding region is 82 and 85% identical at the nucleotide and amino acid levels, respectively, between the two species. There are two major classes of clones, differing only in the lengths of their 3’untranslated ends, suggesting that the different ARPP‐21 mRNAs are derived from the use of alternate polyadenylation sites. Both major mRNA species, 2.6 and 0.7 kb, are present at the highest concentration in the striatum, followed by the cortex, consistent with previous immunocytochemical results. Southern blot analysis reveals a simple hybridization pattern, consistent with the presence of a single rat gene encoding ARPP‐21. The steady‐state levels of the ARPP‐21 mRNAs are developmentally regulated but, in the neonatal and mature animal, are not altered following 6‐hydroxydopamine lesions of the substantia nigra or by pharmacologic treatments that up‐regulate the D1‐ or D2‐dopamine receptors.
[3H]SCH 39166, A New D1‐Selective Radioligand: In Vitro and In Vivo Binding Analyses
Authors: McQuade Robert D. , Duffy Ruth A. , Anderson Cheryl C. , Crosby Gordon , Coffin Vicki L. , Chipkin Richard E. , Barnett Allen 
Published: October 2006

AbstractSCH 39166 {(‐)‐trans‐6,7,7a,8,9,13b‐hexahydro‐3‐chloro‐2‐hydroxy‐N‐ methyl‐5H ‐ benzo ‐[d]naphtho[2,1b]azepine} has recently been described as a selective D1 antagonist and has entered clinical trials for the treatment of schizophrenia. The tritiated analogue of this compound, [3H]SCH 39166, has now been synthesized and characterized for its in vitro and in vivo binding profiles. [3H]SCH 39166 binds to D1 receptors in a saturable. high‐affinity fashion, with a KDof 0.79 nM. In competition studies, D1‐selective antagonists like SCH 23390 displaced the binding of [3H]SCH 39166 with nanomolar affinities, whereas antagonists of other receptors exhibited poor affinity. In vivo, [3H]SCH 39166 bound to receptors in rat striatum in a fashion suggestive of D1 selectivity. Further. when the time course for the binding of [3H]SCH 39166 was compared with the behavioral time course of the unlabeled compound, the two durations of action were virtually indistinguishable. Similar studies were performed for SCH 23390 and its tritiated analogue, but the in vivo binding of this radioligand exhibited a duration of action far greater than the behavioral activity of the unlabeled drug. In concert, these data demonstrate that [3H]SCH 39166 selectively labels D1 receptors in vitro and in vivo, and that this drug is superior for in vivo imaging of the D1 receptor.
Evidence for an Association of the 15‐kDa Proteolipid of Mediatophore with a 14‐kDa Polypeptide
Authors: Israël M. , Morel N. , Lesbats B. 
Published: October 2006

AbstractThe present report shows that mediatophore, a nerve terminal membrane protein that translocates acetyl‐choline on calcium action, forms a complex with a 14‐kDa polypeptide. The complex was identified based on the following results, (a) A polyclonal antimediatophore antiserum that immunoprecipitates activity precipitates both the 15‐and 14‐kDa polypeptides. (b) After HPLC purification of mediatophore, both antigens were found in the same peak, (c) After 3‐[(3‐cholamidopropyl)dimethylarnmonio]‐1‐pro‐panesulfonate solubilization of presynaptic membranes or of the purified mediatophore, an immunoaffinity column made with the anti‐14‐kDa antigen monoclonal antibody retained both the 14‐kDa and the 15‐kDa polypeptide. Similarly, im‐munoprecipitation experiments using protein A‐coated beads sedimented an immunocomplex in which both antigens were found, (d) The 14‐kDa antigen could be localized in the syn‐aptosomal membrane where mediatophore and its 15‐kDa component are found.
Redox Modulation of N‐Methyl‐D‐Aspartate‐Stimulated Neurotransmitter Release from Rat Brain Slices
Authors: Woodward John J. , Blair Robert 
Published: October 2006

AbstractRat brain cortical slices released tritiated norepi‐nephrine ([3H]NA) during a 2‐min stimulation with N‐methyl‐d‐aspartate (NMDA). Dithiothreitol (DTT; 0.1–5 mM), present for 6 min prior to stimulation, dose‐depen‐dently increased the release of [3H]NA from cortical slices stimulated with a maximally effective concentration of NMDA (500 μM). Similar results were observed for [3H]NA release from hippocampal slices and tritiated and endogenous dopamine release from striatal slices. DTT treatment also markedly shifted the dose‐response curve of NMDA to the left. Cortical slices released approximately the same amount of [JH]NA with 10 μM NMDA following DTT treatment (about 5%) as non‐DTT‐treated control slices did with 500 μM NMDA. The effects of DTT were fully reversed by subsequent treatment with 5,5′‐dithio‐bis(2‐nitrobenzoic acid) (DTNB; 0.5 mM). DTT treatment did not significantly alter the ability of magnesium (1.3 mM) or the polyamine antagonist arcaine to block the NMDA‐stimulated release of [3H]NA. In contrast, DTT treatment significantly attenuated the antagonist effects of the competitive glycine antagonist, 7‐chlorokynurenic acid, and the competitive NMDA antagonist, 2‐aminophosphonopentanoic acid. These results suggest that oxidation and reduction of disulfide bonds located within the NMDA receptor complex might regulate the activation of the NMDA receptor. This could have important consequences in vivo if endogenous oxidizing/reducing systems are found to have similar effects on NMDA‐stimulated responses.
Classical Conditioning‐Induced Changes in Low‐Molecular‐Weight GTP‐Binding Proteins in Rabbit Hippocampus
Authors: Nelson T. J. , Sanchez‐Andres J.‐V. , Schreurs B. G. , Alkon D. L. 
Published: October 2006

AbstractClassical conditioning of Hermissenda, involving paired light‐rotation events, results in a 30–35% decrease in the levels of a 20‐kDa G protein (cp20). To test whether a similar protein exists in vertebrates, rabbits were trained to associate a tone with periorbital electrical stimulation and g proteins were analyzed by photoaffinity labeling with [œ‐32P]GTP‐azidoanilide. A 20‐kDa G protein similar to cp20 decreased by 36% in the hippocampus of rabbits subjected to paired tone and electrical stimulation, but not in unpaired controls. Learning‐specific decreases were also found in the amount of ras protein.
Activation of Tyrosine Hydroxylase by Nicotine in Rat Adrenal Gland
Authors: Fossom Linda H. , Sterling Carol , Tank A. William 
Published: October 2006

AbstractThe administration of nicotine activates tyrosine hydroxylase in the rat adrenal gland. This activation is apparently maximal 25 min after a single subcutaneous injection of nicotine at 2.3 mg/kg. Repeated injections of nicotine (seven injections once every 30 min) are associated with a persistent activation of adrenal tyrosine hydroxylase for at least 3 h. The nicotinic receptor antagonist hexamethonium docs not significantly inhibit the nicotine‐mediated activation of tyrosine hydroxylase in innervated adrenal glands. However, hexamethonium completely blocks the activation of adrenal tyrosine hydroxylase by nicotine in denervated adrenal glands. Furthermore, even though a single injection of nicotine activates tyrosine hydroxylase in both innervated and denervated adrenal glands, repeated injections of nicotine do not activate tyrosine hydroxylase in denervated adrenal glands. Our results suggest that the systemic administration of nicotine activates adrenal tyrosine hydroxylase by two mechanisms: (1) via direct interaction with adrenal chro‐maffin cell nicotinic receptors; and (2) via stimulation of the CNS leading to the release from the splanchnic nerve of substances that interact with adrenal chromaffin cell receptors other than the nicotinic receptor.
Incorporation of [3H]Arachidonic and [14C]Eicosapentaenoic Acids into Glycerophospholipids and Their Metabolism via Lipoxygenases in Isolated Brain Cells from Rainbow Trout Oncorhaynchus mykaiss
Authors: Tocher Douglas R. , Bell J. Gordon , Sargent John R. 
Published: October 2006

AbstractThe incorporation of [3H]arachidonate ([3H]AA) and [14C]eicosapentaenoate ([14C]EPA) into glycerophos‐pholipids was studied in isolated brain cells from rainbow trout, a teleost fish whose lipids are rich in (n‐3) polyunsaturated fatty acids (PUF As), EPA was incorporated into total lipid to a greater extent than AA, but the incorporation of both PUF As into total glycerophospholipids was almost identical. The incorporation of both AA and EPA was greatest into phosphatidylethanolamine (PE). However, when expressed per milligram of individual phosphoglycerides, both AA and EPA were preferentially incorporated into phospha‐tidylinositol (PI), the preference being significantly greater with AA. On the same basis, significantly more EPA than AA was incorporated into phosphatidylcholine (PC). When double‐labelled cells were challenged with calcium ionophore A23187, the 3H and 14C released from the cells closely paralleled each other, peaking at 10 min after addition of ionophore.The 12‐monohydroxylated derivative was the predominant lipoxygenase product from both AA and EPA with a rank order of 12‐hydroxyeicosatetraenoic acid (12‐HETE) > leukotriene B4 (LTB4) > 5‐HETE > 15‐HETE for the AA products and 12‐hydroxyeicosapentaenoic acid (12‐HEPE) > 5‐HEPE > LTB5 > 15‐HEPE for EPA products. The 3H/14C (dpm/dpm) ratios in the glycerophospholipids, total released radioactivity, and the lipoxygenase products suggested that PC rather than PI was the likely source of eicosanoid precursors in trout brain cells.
Ranakinin: A Novel NK1 Tachykinin Receptor Agonist Isolated with Neurokinin B from the Brain of the Frog Rana ridibunda
Authors: O'Harte Finbarr , Burcher Elizabeth , Lovas Sandor , Smith D. David , Vaudry Hubert , Conlon J. Michael 
Published: October 2006

AbstractAn extract of the whole brain of the frog Rana ridibunda contained high concentrations of substance P‐like immunoreactivity, measured with an antiserum directed against the COOH‐terminal region of mammalian substance p and neurokinin b‐like immurtoreactivity, measured with an antiserum directed against the NH2‐terminus of neurokinin B. The primary structure of the substance p‐related peptide (ranakinin) was established as: Lys‐Pro‐Asn‐Pro‐Glu‐Arg‐Phe‐Tyr‐Gly‐Leu‐Met‐NH2. Mammalian substance P was not present in the extract. The primary structure of the neurokinin b‐related peptide was established as: Asp‐Met‐His‐Asp‐Phe‐Phe‐Val‐Gly‐Leu‐Met‐NH2. This amino acid sequence is the same as that of mammalian neurokinin B.Ranakinin was equipotent with substance p and [Sar9,‐Met(O2)11]substance p in inhibiting the binding of 125I‐Bolton‐Hunter‐[Sar9, Met(O2)11]substance p, a selective radio‐ligand for the NK1 receptor, to binding sites in rat subman‐dibular gland membranes (IC50 1.6 ± 0.3 nM; n = 5). It is concluded that ranakinin is a preferred agonist for the mammalian NK1 tachykinin receptor subtype.
Characterization of a Novel Serotonin Receptor Subtype (5‐HTls) in Rat CNS: Interaction with a GTP Binding Protein
Authors: Zemlan Frank P. , Schwab Eileen F. 
Published: October 2006

AbstractThree pharmacologically distinct high‐affinity [3H]serotonin ([3H]5‐HT) binding sites were identified in spinal cord synaptosomes. [3H]5‐HT competition studies using selective 5‐HT1A receptor ligands indicated that ∼25% of high‐affinity synaptosomal [3H]5‐HT binding was inhibited by 5‐HT1A‐selective compounds, an estimate consistent with [3H](±)‐8‐hydroxy‐2‐(di‐n‐propylamino)tetralin([3H]8‐OH‐DPAT) saturation experiments in which 5‐HT1A receptors were directly labeled. [3H]5‐HT competition studies using high‐affinity 5‐HT1B compounds performed in the presence of 100 nM 8‐OH‐DPAT (to block 5‐HT1A receptors) indicated that∼26% of all specific, high‐affinity [3H]5‐HT binding to spinal cord synaptosomes was to 5‐HT1B receptors. [3H]5‐HT competition studies performed in the presence of 100 nM 8‐OH‐DPAT and 10 nM RU 24969 (to block 5‐HT1A and 5‐HT1B receptors, respectively) indicated that the remaining 49% of [3H]5‐HT binding did not possess the phar‐macologic profile previous reported for 5‐HT1c, 5‐HT1D, 5‐ HT1E, 5‐HT2, or 5‐HT3 receptors. This residual 49% of [3H]5‐ HT binding to spinal cord synaptosomes observed in the presence of 100 nM 8‐OH‐DPAT and 10 nM RU 24969 (subsequently referred to as “5‐HTls”) displayed high affinity and saturability (KD= 4.7 nM) in association/dissociation and saturation experiments. Addition of 300 μM GTP or the nonhydrolyzable form of GTP, 5′‐guanylylimidodiphosphate, inhibited [3H]5‐HT binding to 5‐HT1S receptors in saturation experiments by 35 and 57%, respectively, whereas ATP was without effect. [3H]5‐HT competition studies identified several 5‐HT agonists and antagonists with a high or moderately high affinity for 5‐HT1s receptors. Although 5‐HT1s receptors were the predominant 5‐HT1 receptor subtype present in spinal cord, no significant density of 5‐HT1s receptors was found in brainstem or frontal cortex.