bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expression of carbonic anhydrase II gene in early brain cells as revealed by in situ hybridization and immunohistochemistry
Authors: De Vitry F. , Gomes D. , Rataboul P. , Dumas S. , Hillion J. , Catelon J. , Delaunoy J.‐P. , Tixier‐Vidal A. , Dupouey P. 
Published: January 2005

AbstractA mouse carbonic anhydrase (CA II) complementary(c) DNA probe was used for in situ hybridization on mouse brain cultured cells in order to follow CA II gene expression during brain development. An improved method was established using biotinated probes that resulted in a high sensitivity and an absence of background; this method could be combined with immunohistochemistry. Hypothalamic cells of embryonic day (ED) 12–14 mice were cultured for various periods. Chronologic appearance of CA II messenger(m)RNA and protein was studied. The CA II gene transcripts are detectable as early as ED 12–13, although the protein they encode is not detectable until ED 17–18. Gene expression is restricted to 0.1% of the total population. Northern blot analysis confirmed the presence of CA II transcripts in embryonic hypothalamus. At postnatal stage, the majority of glial cells express both the CA II mRNA and the protein. Our results favour the early appearance of a glial lineage in a precise area of the developing CNS. The precocity of CA II gene transcription makes in situ hybridization an invaluable approach in defining the onset of nerve cell lineages during embryonic development.
Stimulus‐coupled taurine efflux from cerebellar neuronal cultures: On the roles of Ca++ and Na+
Authors: Philibert R. A. , Rogers K. L. , Dutton G. R. 
Published: January 2005

AbstractPrimary cultures of cerebellar neurons obtained from 7–9‐day‐old rats and grown 7–9 days in vitro (DIV) were used to study the effects of Na+ and Ca++ on K+‐evoked taurine release. These cultures, made up largely of granule neurons (90%) and inhibitory interneurons (5–7%), produced a dose‐dependent, depolarization‐evoked taurine release that was Ca++‐dependent at 40 mM K+, and Ca++‐independent at K+ concentrations above 40 mM. The dihydropyridine Ca++ channel agonist BAY K 8644 (1 μM) augmented 30 mM K+‐evoked release, while the antagonist nifedipine (5 μM) abolished both the BAY K 8644‐ and K+‐enhanced release. Depolarization with the Na+ channel agonist veratridine (50 μM) stimulated taurine efflux, which was completely blocked by pretreatment with tetrodotoxin (2 μM). However, 50 mM K+‐evoked taurine release was not affected by tetrodotoxin pretreatment. Substitution of choline Cl for NaCl partially antagonized 50 mM K+‐evoked release, and by itself, the Na+ ionophore monensin (50 μM) stimulated release. These results suggest that both K+‐evoked and basal taurine release from primary cerebellar neuronal cultures are sensitive to the levels of both intracellular and extracellular Na+ and Ca++ In contrast to previous findings using cerebellar astrocytes, neuronal L‐type Ca++ channels, but not voltage‐dependent Na+ channels, also appear to be necessary. The implications of these results on taurine's status as a putative neurotransmitter are discussed.
Brain neocortex influence on the mononuclear phagocyte system
Authors: Neveu P. J. , Barnéoud P. , Georgiades O. , Vitiello S. , Vincendeau P. , Le Moal M. 
Published: January 2005

AbstractThe cerebral neocortex is known to modulate asymmetrically certain components of the immune system. It was previously shown that large ablation of the left cortex reduces B and T cell‐mediated responses, whereas symmetrical right lesions enhance these responses. We have studied the immunomodulatory role of the brain cortex on the mononuclear phagocytic system. Resident and BCG‐activated macrophages were investigated in female C3H/He mice at 8–10 weeks after right or left cortical ablation. After an intraperitoneal injection of BCG, the number of peritoneal macrophages was found to be lower in both right‐ and left‐lesioned mice, the difference being stronger and more significant in left‐lesioned animals than in sham‐operated controls. Furthermore, the oxidative metabolism as assessed by chemiluminescence was depressed only in left‐lesioned mice. On the other hand, cortical lesions were shown to have no effect on either the number or the endocytic activity of resident peritoneal macrophages. The possible implication of the brain neocortex on infectious diseases was assayed by using the Trypasonoma musculi model, in which macrophages are known to be effective in parasite eradication. Although the number of peritoneal macrophages was significantly depressed after left cortical lesions 11 days after T. musculi inoculation, the course of the infection was not modified significantly. Our results argue in favor of brain neocortex modulation of the mononuclear system.
Paradoxical and subtype‐specific effects of opiate antagonists on the expression of opioid receptors in rat brain cultures
Authors: Barg J. , Levy R. , Simantov R. 
Published: January 2005

AbstractCultures of aggregating fetal rat brain cells express μ, δ, and k opioid receptors. The potent and longlasting opioid antagonist naltrexone was used to investigate whether different regulatory mechanisms are involved in the expression of the three receptor subtypes. In cultures treated for seven days, naltrexone increased dose‐dependently the binding of 3H‐diprenorphine to the three receptor subtypes, with the μ sites being affected at a lower concentration than the other two; A Scatchard analysis indicated that this receptor up‐regulation was obtained by an increase in the BMax, with no significant change in the affinity of the ligand to the receptors. In contrast to these effects in cultures treated for 7 days, it was surprising to find that a 48 hr treatment with naltrexone had an apparent converse and subtypespecific influence; the antagonist decreased significantly the binding of 3H‐diprenorphine to both μ and δ receptors but had no effect on k sites. Two other opioid antagonists, naloxone and levallorphan, had a similar effect. Further analysis of naltrexone's mode of action was obtained by studying its effect on the adenylate cyclase activity. Of several inducers of this enzyme, the β‐adrenergic inducer isoproterenol gave the highest increase in cyclic AMP. Naltrexone had no significant effect on the basal adenylate cyclase activity but it altered the pattern of cyclic AMP formation in isoproterenol‐stimulated cultures. Overall, the results indicate that in addition to its classic antagonistic activity, naltrexone exhibits in fetal brain aggregates some properties associated with opiate agonists.
Age‐related modification of enzyme activities in synaptosomes isolated from rat cerebral cortex
Authors: Curti D. , Benzi G. 
Published: January 2005

AbstractIn synaptosomes from rat cerebral cortex, the potential catalytic activity of some enzymes related to energy metabolism—namely, phosphofructokinase and citrate synthase—is not affected by aging. In contrast, the maximum velocity (Vmax) of cytochrome oxidase and of pyruvate dehydrogenase decreases in aged rats. A marked increase is found in the Vmax of glucose 6‐phosphate dehydrogenase in aged rats and could be related to the availability of NADPH for antiperoxidative processes.Pretreatments of experimental animals with certain drugs were done to investigate the plasticity of enzyme proteins during aging. Papaverine, which acts on macrocirculation, is ineffective, but delta‐yohimbine acting on microcirculation and metabolism and almitrine acting on oxygen availability both could interfere with the potential activity of some enzymes. However, their influence differs with the age of the rats.
Influence of laminin on the responsiveness of early chick embryo neural tube neurons to nerve growth factor
Authors: Heaton M. B. 
Published: January 2005

AbstractDissociated neurons from the neural tube containing the trigeminal motor nucleus from early chick embryos were cultured on laminin or collagen‐polyornithine substrates, with and without nerve growth factor (NGF). Control cultures were grown in similar conditions with cytochrome‐C. It was found that neuronal survival was not affected by NGF or cytochrome‐C, but it was enhanced by laminin. The expression of neuritic processes, however, was significantly enhanced in the presence of NGF on both laminin and collagen‐polyornithine surfaces, with the greatest number of neurons producing processes seen in the laminin‐plus‐NGF group. The length of processes was similarly enhanced by laminin and by NGF. Cytochrome‐C did not influence any of these measures. The results indicate that while laminin potentiates the NGF effect on these early neuronal populations, NGF in conjunction with other substrata can have similar, though less dramatic, effects. These results, together with prior evidence of NGF receptors and specific NGF retrograde transport, suggest that this growth factor may play a significant role in the normal ontogeny of early motoneuron populations.
Monoclonal antibody detects embryonic epitope specific for nerve‐derived transferrin
Authors: Festoff B. W. , Munoz P. A. , Patel M. K. N. , Harris M. , Beach R. L. 
Published: January 2005

AbstractMonoclonal antibodies were generated against transferrin purified from chick embryo extract by fusing spleen cells from BALB/∼c mice immunized against embryonic transferrin, with myeloma cells. Antibodies produced by the selected hybridoma clones were all type IgG. Twelve clones were selected for secretion of antibodies to the embryo extract‐derived transferrin, and three clones were studied extensively. Immunoblotting was used to demonstrate antibody binding to several avian transferrin proteins derived from adult chicken serum, adult chicken peripheral nerves, and ovotransferrin. Screening and detailed epitope analysis were accomplished by solid‐phase immunoassay. The results indicated that two clones, 2G9.1 and 2B11.1, recognized the embryonic and egg antigens in preference to the adult proteins. However, a third clone, 6H2.1, recognized the nerve‐derived transferrin preferentially to both the embryonic and adult serum antigens. None of the clones recognized the serum‐derived transferrin in preference to the other antigens. These results indicate that embryonic epitope(s) are conserved in the nerve‐ but not the serum‐derived transferrin. They also show that the neural antigen has site(s) distinct from the embryonic proteins. No changes in displacement curves were observed after these proteins were digested with neuraminidase, indicating that the epitope differences discovered are not intimately related to sialic acid residues on the various transferrins.
Response of human T lymphocyte lines to myelin basic protein: Association of dominant epitopes with HLA class II restriction molecules
Authors: Chou Y. K. , Vainiene M. , Whitham R. , Bourdette D. , Chou C. H.‐J. , Hashim G. , Offner H. , Vandenbark A. A. 
Published: January 2005

AbstractIn animals, the selection in vitro of T cell lines to myelin basic protein (MBP) can define immunodominant and encephalitogenic epitopes which are preferentially associated with class II major histocompatibility (MHC) molecules. These principles were used to evaluate the specificity and MHC restriction of 14 human MBP‐reactive T cell lines selected from normal individuals and patients with multiple sclerosis (MS) and other neurological diseases (OND). The four normal T cell lines recognized single, separate immunodominant MBP epitopes which were restricted by MHC molecules from the DR or in one case the DP class II locus. In contrast, the MS and OND T cell lines recognized multiple MBP epitopes, each in association with a discrete class II MHC molecule from the DR or DQ locus. Overall, HLA‐DR molecules were used preferentially to associate with epitopes on human MBP, restricting 26/33 responses. As predicted from animal studies, T cells from genetically disparate individuals responded to different immunodominant epitopes on human MBP in association with distinct MHC class II molecules. HLA‐DR2, which is overrepresented in MS patients, possessed an unusual capacity to restrict all eight epitopes identified on MBP in this study. These data provide the first evidence of genetically restricted human T cell recognition of potentially encephalitogenic epitopes of MBP.
Presence of α‐melanocyte‐stimulating hormone‐like immunoreactivity in the innervation of amphibian skeletal muscle
Authors: Oren N. , Micevych P. E. , Letinsky M. S. 
Published: January 2005

AbstractAmphibian motor nerve terminals are sensitive to a wide variety of peptides, including α‐melanocytestimulating hormone (α‐MSH). We determined the presence and distribution of α‐MSH‐like immunoreactivity (α‐MSHLI) in the innervation of the cutaneous pectoris muscle from bullfrog (Rana catesbeiana) tadpoles and postmetamorphic froglets, and adult frogs (R. catesbeiana and R. pipiens). α‐MSHLI was found in unmyelinated, noncholinergic axons, in motor axons, and in motor nerve terminals. In motor axons, α‐MSHLI was predominantly associated with neurofilaments. The distribution of this form of α‐MSHLI changed during development and seasonally in adult frogs. The possible functional roles of this α‐MSHLI are discussed.
Induction of morphological differentiation of human neuroblastoma cells is accompanied by induction of tissue‐type plasminogen activator
Authors: Neuman T. , Stephens R. W. , Salonen E.‐M. , Timmusk T. , Vaheri A. 
Published: January 2005

AbstractHuman SH‐SY5Y neuroblastoma cells treated with retinoic acid, 12‐O‐tetradecanoyl‐phorbol‐13‐acetate (TPA) or nerve growth factor differentiated morphologically to neuronlike cells with increased amounts of neurofilament protein and mRNA. All three effetors induced an increase in the amount of relative molecular weight (Mr) 70 000 tissue‐type plasminogen activator (t‐PA) and its mRNA, as determined by immunocapture, enzyme activity, and Northern blotting analyses. About 90% of the t‐PA activity was secreted to the culture medium. In contrast, of the three effectors studied, only TPA induced transcription of the proto‐oncogene c‐fos, studied as a control gene responsive to various stimuli, and induced a rapid increase in urokinase‐type PA (u‐PA). Most of the u‐PA activity induced by TPA remained cell‐associated. Because induction of differentiation correlated closely with induction of t‐PA, and not u‐PA, the authors propose that t‐PA may have a functional role in the morphological differentiation of neuronal cells.
GABAA and GABAB receptors are functionally active in the regulation of catecholamine secretion by bovine chromaffin cells
Authors: Castro E. , Oset‐Gasque M. J. , González M. P. 
Published: January 2005

AbstractGABA stimulates the basal catecholamine release from adrenal bovine chromaffin cells in a calciumdependent manner. This release represents about 70% of that obtained by similar doses of nicotine under similar experimental conditions. This effect is mediated by GABAA receptor sites present in chromaffin cells, since it was mimicked by muscimol and reversed by bicuculline. In addition, GABA, through its GABAA receptors, increases the catecholamine release evoked by submaximal doses of aicotine, but it has no effect on nicotine‐evoked secretion of catecholamines when nicotine was given at maximal doses. These results seem to indicate that both nicotine and GABA release catecholamines from the same intracellular pool. In contrast, baclofen, a GABAB receptor agonist, depressed both basal and nicotineevoked catecholamine release; this result indicates that in addition to GABAA control of catecholamine secretion by chromaffin cells, there is a GABAB control of this function. These results support the existence of a dual regulation of catecholamine secretion by both the GABAA and GABAB receptors in a similar way as that proposed for muscarinic and nicotinic cholinergic receptors.
Isolation, characterization, and application of monoclonal antibodies to rat tyrosine hydroxylase
Authors: Kwan S.‐W. , Patel N. T. , Vulliet P. R. , Hall F. L. , Denney R. M. , Shen R. S. , Westlund K. N. , Abell C. W. 
Published: January 2005

AbstractTyrosine hydroxylase (TH, tyrosine 3‐monooxygenase; EC 1.14.16.2) activity in crude extracts of rat pheochromocytoma, rat brain, and bovine adrenal medulla can be immunoprecipitated in an indirect assay by monoclonal antibodies prepared against partially purified rat pheochromocytoma TH. One of tese monoclonal antibodies, TH‐2D8hyphen;2, can be used for immunocytochemical localization of TH in cell bodies, dendrites, and axons in catecholaminergic neurons (e.g., cells in the substantia nigra) of rat brain and in the cell body, neurites, and growth cones of rat pheochromocytoma cells after treatment with nerve growth factor. When linked to Affihyphen;gel 10, this monoclonal antibody can also be used for immunoaffinity purification of rat and bovine TH. These results suggest that THhyphen;2D8hyphen;2 is a valuable reagent with which to investigate the localization, physiological regulation, and function of this important enzyme.
Post‐translational processing in model neuroendocrine systems: Precursors and products that coordinate reproductive activity in Aplysia and Lymnaea
Authors: Nagle G. T. , Painter S. D. , Blankenship J. E. 
Published: January 2005

AbstractThe regulation of egg‐laying behavior in the hermaphroditic marine mollusc Aplysia has been an important model system that has provided insight into the cellular and molecular bases of neuroendocrine function. The advantages of this system derive primarily from the unique characteristics of the bag cells, two clusters of neurosecretory cells whose peptide products initiate and coordinate egg deposition. In particular, the large number of bag cell neurons in a single animal and their relative isolation from other elements of the nervous system facilitate biochemical analyses of the peptides synthesized and released by the cells. Moreover, the episodic nature of bag cell electrical activity, combined with the relative simplicity of the Aplysia nervous system and the stereotypic nature of the behaviors exhibited during egg deposition, provide unusually favorable opportunities for investigating neuropeptide action and function. This review will focus on neuropeptide synthesis and processing in the bag cells and in other organs expressing structurally related genes.
Differentiation of PC12 cells with v‐src: Comparison with nerve growth factor
Authors: Rausch D. M. , Dickens G. , Doll S. , Fujita K. , Koizumi S. , Rudkin B. B. , Tocco M. , Eiden L. E. , Guroff G. 
Published: January 2005

AbstractThe PC12 rat pheochromocytoma cell line is used extensively as a model to study neuronal differentiation. These cells resemble adrenal chromaffin cells, differentiating both morphologically and biochemically when cultured in the presence of dexamethasone, but develop a sympathetic neuron‐like phenotype when cultured in the presence of nerve growth factor. Expression of the protein product of the v‐src oncogene in PC12 cells also induces neurite outgrowth similar to that resulting from nerve growth factor treatment (Alema et al: Nature 316:557–559, 1985). It is thus possible that c‐src or a src‐like tyrosine kinase participates in the signal transduction pathway by which nerve growth factor acts on PC12 cells. In this study a temperature‐sensitive v‐src gene has been introduced into PC12 cells. When cultures of these srctransformed cells are switched from the nonpermissive (40°C) to the permissive (37°C) temperature they elaborate neurites. The differentiation induced by src has been compared with that induced by nerve growth factor by determining whether srctransformed PC12 cells at 37°C exhibit the same biochemical alterations as those induced in PC12 cells treated with nerve growth factor. Neurite extension at 37°C in v‐src—transformed cells, like NGF‐induced differentiation, is accompanied by an increase in the nerve growth factor‐inducible large external (NILE) protein. However, neurite extension in v‐src‐transformed cells is not blocked by the protein kinase inhibitor K‐252a, which completely blocks NGF‐induced neurite extension. Likewise, EGF receptor down‐regulation and the development of saxitoxin and tetanus toxin binding sites are either much reduced or completely absent in src‐differentiated compared with NGF‐differentiated PC12 cells.
v‐src genes stimulate neurite outgrowth in pheochromocytoma (PC12) variants unresponsive to neurotrophic factors
Authors: Eveleth D. D. , Hanecak R. , Fox G. M. , Fan H. , Bradshaw R. A. 
Published: January 2005

AbstractThe NGF‐nonresponsive rat pheochromocytoma PC12 variant nnr5, isolated by Green et al. (J Cell Biol 102:830–843, 1986), responds poorly or not at all to fibroblast growth factor. Transformation of PC‐12nnr5 cells with v–src‐expressing retroviruses results in vigorous neurite outgrowth, similar to that seen in the parent cell line. Thus though the PC12nnr5 cell line has a greatly impaired ability to respond to neurotrophic factors it still may extend neurites. This data is consistent with a model in which PC12nnr5 cells are unable to propagate intracellular second messengers, and this defect may be related to the expression of c‐src gene products.
Neuron‐specific splicing of C‐SRC cDNA RNA in human brain
Authors: Pyper J. M. , Bolen J. B. 
Published: January 2005

AbstractThe C‐SRC, C‐YES, and FYN genes encode three closely related tyrosine protein kinases that are expressed in human neural tissues. A unique form of the C‐SRC gene has been demonstrated to be expressed in avian and murine brain tissues as the result of alternative splicing between the third and fourth exons. This neuronal‐specific splicing event adds to the C‐SRC mRNA an 18 base pair exon capable of encoding the same six amino acids in both avian and murine neural tissues. The C–YES and FYN genes share with C‐SRC similar exon‐intron boundaries and a high degree of amino acid sequence homology in the 3/4 exon coding region. However, potential alternative splicing of the C‐YES and FYN genes in this region has not been previously investigated. In this study we have compared the expression of C‐SRC, C‐YES, and FYN RNAs in human lung, liver, brain, and placenta tissues and prepared cDNA clones spanning exons 3 and 4 for each of these genes from the different tissues. Sequence analysis of these cDNA clones revealed that the splicing patterns for the FYN and C‐YES genes were the same among the various tissues, whereas C‐SRC cDNAs isolated from brain contained 18 additional bases with the capacity to code for the same six amino acids present in the neural‐specific forms of avian and murine pp60c‐src.