J Thibault

Russian Academy of Medical Sciences, Moskva, Moscow, Russia

Are you J Thibault?

Claim your profile

Publications (98)269.55 Total impact

  • [show abstract] [hide abstract]
    ABSTRACT: Non-dopaminergic neurons expressing individual complementary enzymes dopamine (DA) synthesis were shown to produce DA in cooperation [Ugrumov, M., Melnikova, V., Ershov, P., Balan, I., Calas A., 2002. Tyrosine hydroxylase- and/or aromatic L-amino acid decarboxylase-expressing neurons in the rat arcuate nucleus: ontogenesis and functional significance. Psychoneuroendocrinology 27, 533-548; Ugrumov, M.V., Melnikova, V.I., Lavrentyeva, A.V., Kudrin, V.S., Rayevsky, K.S., 2004. Dopamine synthesis by non-dopaminergic neurons expressing individual complementary enzymes of the dopamine synthetic pathway in the arcuate nucleus of fetal rats. Neuroscience 124, 629-635]. This study was aimed at testing our hypothesis that the cooperative synthesis of DA in non-dopaminergic neurons is an adaptive reaction under functional insufficiency of the dopaminergic system. Functional insufficiency of the tuberoinfundibular dopaminergic system was provoked by 6-OHDA-induced degeneration of dopaminergic neurons in the arcuate nucleus in adult rats. Bienzymatic (dopaminergic) neurons and monoenzymatic neurons expressing tyrosine hydroxylase (TH) or aromatic L-amino acid decarboxylase (AADC) were detected with a double-immunofluorescent technique on cryostat sections. The 6-OHDA-induced degeneration of dopaminergic neurons was accompanied by a significant increase of the number of monoenzymatic TH neurons and AADC neurons that appears to support our hypothesis. The reaction of bienzymatic and monoenzymatic neuron populations to the 6-OHDA administration occurred to be region-specific. The former disappeared in the dorsomedial region of the arcuate nucleus while the latter increased in the ventrolateral region. Thus, degeneration of dopaminergic neurons in the arcuate nucleus of adult rats is accompanied by the expression of individual enzymes of DA synthesis in non-dopaminergic neurons that may be an adaptive reaction.
    Journal of Chemical Neuroanatomy 08/2005; 30(1):27-33. · 2.48 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: We evaluated the topographic relations between tyrosine hydroxylase (TH)- and/or aromatic L-amino acid decarboxylase (AADC)-immunoreactive neurons in the arcuate nucleus (AN), as well as between TH- and/or AADC-immunoreactive axons in the median eminence (ME) in rats at the 21st embryonic day, 9th postnatal day, and in adulthood. The double-immunofluorescent technique in combination with confocal microscopy was used. Occasional bienzymatic neurons but numerous monoenzymatic TH- or AADC-immunoreactive neurons were observed in fetuses. There was almost no overlap in the distribution of monoenzymatic neurons, and therefore few appositions were observed in between. In postnatal animals, numerous bienzymatic neurons appeared in addition to monoenzymatic neurons. They were distributed throughout the AN resulting in the increased frequency of appositions. Furthermore, specialized-like contacts between monoenzymatic TH- and AADC-immunoreactive neurons appeared. The quantification of the fibers in the ME showed that there were large specific areas of the monoenzymatic TH-immunoreactive fibers and bienzymatic fibers in fetuses, followed by the gradual reduction of the former and the increase of the latter to adulthood. The specific area of the monoenzymatic AADC-immunoreactive fibers in fetuses was rather low, and thereafter increased progressively to adulthood. The fibers of all the types were in apposition in the ME at each studied age. Close topographic relations between the neurons containing individual complementary enzymes of dopamine synthesis at the level of cell bodies and axons suggest functional interaction in between.
    Journal of Chemical Neuroanatomy 08/2002; 24(2):95-107. · 2.48 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: In this double-immunofluorescence study, we first quantified the neurons of the arcuate nucleus as immunoreactive (+) for tyrosine hydroxylase (TH) and/or aromatic L-amino acid decarboxylase (AADC) in rats at embryonic day 21 (E21), at postnatal day 9 (P9), and in adulthood by using conventional fluorescent or confocal microscopy. On E21, monoenzymatic (TH(+)AADC immunonegative (-) and TH(-)AADC(+)) neurons and bienzymatic (TH(+)AADC(+)) neurons accounted for 99% and 1%, respectively, of the whole neuron population expressing enzymes of dopamine synthesis. Further development was characterized by the dramatic increase in TH(+)AADC(-) dorsomedial and TH(+)AADC(+) dorsomedial populations from E21 to P9 as well as by the increase in the TH(+)AADC(+) dorsomedial population (in females) and a drop in the TH(+)AADC(-) ventrolateral and TH(+)AADC(-) dorsomedial (in males) populations from P9 to adulthood. In contrast to TH(+)AADC(-) (in males) and TH(+)AADC(+) neurons, the TH(-)AADC(+) neurons did not change in number from E21 to adulthood. Thus, in rat fetuses, the neurons synthesizing TH and/or AADC were mainly monoenzymatic, whereas during postnatal life the fraction of bienzymatic neurons increased by up to 60%.
    The Journal of Comparative Neurology 05/2002; 446(2):114-22. · 3.66 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: Using immunocytochemistry, in situ hybridization and image analysis, we attempted to compare the dynamical expression of tyrosine hydroxylase (TH) and vasopressin (VP) mRNAs and proteins in the magnocellular neurons of the supraoptic nucleus in rats drinking 2% NaCl for 1, 2 and 3 weeks. Three stages in the reaction of VPergic neurons have been distinguished. The initial stage (first week) showed a synchronous activation of TH and VP mRNAs and protein expression as well as an increased number of TH-immunoreactive neurons. The next stage (second week) was characterized by a further increase in the number of TH-immunoreactive neurons. The number of VPergic neurons also increased significantly. Although the TH and VP mRNAs levels fell during the second week of osmotic stimulation, the TH content increased significantly, and the VP content remained at the same level. During the last stage (third week), TH-immunoreactive neurons increased in number and were as numerous as VP-immunoreactive neurons in intact rats. These data suggest that, finally, all the VPergic neurons begin to synthesize TH. The concentrations of VP and TH mRNAs did not change during the third week of osmotic stimulation, while the VP and TH contents increased. Thus, our study shows that there is a correlation between TH expression and VP expression and suggests similar mechanisms for the regulation of VP and TH gene expression and synthesis during long-term osmotic stimulation.
    Brain Research 02/2002; 925(1):67-75. · 2.88 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: We evaluated the topographic relations between tyrosine hydroxylase (TH)- and/or aromatic l-amino acid decarboxylase (AADC)-immunoreactive neurons in the arcuate nucleus (AN), as well as between TH- and/or AADC-immunoreactive axons in the median eminence (ME) in rats at the 21st embryonic day, 9th postnatal day, and in adulthood. The double-immunofluorescent technique in combination with confocal microscopy was used. Occasional bienzymatic neurons but numerous monoenzymatic TH- or AADC-immunoreactive neurons were observed in fetuses. There was almost no overlap in the distribution of monoenzymatic neurons, and therefore few appositions were observed in between. In postnatal animals, numerous bienzymatic neurons appeared in addition to monoenzymatic neurons. They were distributed throughout the AN resulting in the increased frequency of appositions. Furthermore, specialized-like contacts between monoenzymatic TH- and AADC-immunoreactive neurons appeared. The quantification of the fibers in the ME showed that there were large specific areas of the monoenzymatic TH-immunoreactive fibers and bienzymatic fibers in fetuses, followed by the gradual reduction of the former and the increase of the latter to adulthood. The specific area of the monoenzymatic AADC-immunoreactive fibers in fetuses was rather low, and thereafter increased progressively to adulthood. The fibers of all the types were in apposition in the ME at each studied age. Close topographic relations between the neurons containing individual complementary enzymes of dopamine synthesis at the level of cell bodies and axons suggest functional interaction in between.
    Journal of Chemical Neuroanatomy - J CHEM NEUROANAT. 01/2002; 24(2):95-107.
  • Journal of Comparative Neurology - J COMP NEUROL. 01/2002; 446(2):114-122.
  • Source
    [show abstract] [hide abstract]
    ABSTRACT: The influence of serotonin afferents on tyrosine hydroxylase expression in differentiating neurons of the rat arcuate nucleus was studied in vivo and in vitro. In the in vivo study, pchlorophenylalanine inhibited serotonin synthesis in fetal brain from the 11th to the 20th embryonic day. We then used semiquantitative immunocytochemistry to evaluate tyrosine hydroxylase levels in neurons of the arcuate nucleus in fetuses at the 21st embryonic day or in offspring at the 35th postnatal day. Serotonin depletion significantly decreased the tyrosine hydroxylase content in neurons of males and females at the 21st embryonic day and in males at the 35th postnatal day. For the in vitro study, embryonic neurons of the arcuate nucleus were cocultured with embryonic neurons of the raphe nucleus, the main source of serotonin innervation of the brain, including the arcuate nucleus. Co-culture of the neurons resulted in a gender-specific increase of the tyrosine hydroxylase level in the neurons of the arcuate nucleus. In turn, the neurons of the raphe nucleus showed increased levels of serotonin in both males and females, with no sexual dimorphism. Thus, our results suggest a stimulatory, long-lasting effect of serotonin afferents on tyrosine hydroxylase expression in the differentiating neurons of the rat arcuate nucleus during prenatal ontogenesis.
    Neural plasticity. 02/2001; 8(4):271-84.
  • [show abstract] [hide abstract]
    ABSTRACT: In this quantitative and semiquantitative immunocytochemical study, the authors evaluated the differentiation of neurons expressing tyrosine hydroxylase (TH) and/or aromatic L-amino acid decarboxylase (AADC) in the mediobasal hypothalamus (MBH) of male and female rats on embryonic day 18 (E18), E20, and postnatal day 9 (P9). Four neuronal populations were distinguished according to either enzyme expression or neuron location. The earliest and most prominent first population was represented by TH-immunoreactive (IR)/AADC-immunonegative (IN) neurons that were detected initially at E18 and always were located in the ventrolateral region of the MBH. The second population of TH-IN/AADC-IR neurons was observed first at E20 and, after that time, was distributed dorsomedially. The third minor population of TH-IR/AADC-IR neurons initially was detected at E20 and was located dorsomedially. The fourth population was represented by TH-IR/AADC-IN neurons that were distributed in the dorsomedial region at any studied age. The numbers of TH-IR and AADC-IR neurons increased from their initial detection at E18 and E20 until P9. The area of TH-IR and AADC-IR neurons also increased from E18 to E20 and from E20 to P9, respectively. Both TH-IR and AADC-IR neurons showed sex differences in the neuron number, size, and optic density (OD). The numbers of TH-IR neurons in males exceeded those of females at E20 and at P9, although, at P9, sexual dimorphism was a characteristic only of the ventrolateral population. The area and OD of TH-IR neurons from females exceeded those from males in the entire mediobasal hypothalamus (MBH) at E18 and E20 but only in its dorsomedial region at P9. Sexual dimorphism also was an attribute of AADC-IR neurons at E20 and P9. Their number, size, and OD were significantly higher in females than in males. Thus, the MBH of perinatal rats contained two major populations of TH-IR/AADC-IN or TH-IN-AADC-IR neurons and a minor population of TH-IR/AADC-IR neurons. The differentiating neurons expressing either enzyme showed sexual dimorphism.
    The Journal of Comparative Neurology 10/2000; 425(2):167-76. · 3.66 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: The retrochiasmatic area contains the A15 catecholaminergic group and numerous monoaminergic afferents whose discrete cell origins are unknown in sheep. Using tract-tracing methods with a specific retrograde fluorescent tracer, fluorogold, we examined the cells of origin of afferents to the retrochiasmatic area in sheep. The retrogradely labeled cells were seen by observation of the tracer by direct fluorescence or by immunohistochemistry with specific antibodies raised in rabbits or horses. Among the retrogradely labeled neurons, double immmunohistochemistry for tyrosine hydroxylase, dopamine-ß-hydroxylase, and serotonin were used to characterize catecholamine and serotonin FG labeled neurons. The retrochiasmatic area, which included the A15 dopaminergic group and the accessory supraoptic nucleus (SON), received major inputs from the lateral septum (LS), the bed nucleus of the stria terminalis (BNST), the thalamic paraventricular nucleus, hypothalamic paraventricular and supraoptic nuclei, the perimamillary area, the amygdala, the ventral part of the hippocampus and the parabrachial nucleus (PBN). Further, numerous scattered retrogradely labeled neurons were observed in the preoptic area, the ventromedial part of the hypothalamus, the periventricular area, the periaqueductal central gray (CG), the ventrolateral medulla and the dorsal vagal complex. Most of the noradrenergic afferents came from the ventro-lateral medulla (A1 group), and only a few from the locus coeruleus complex (A6/A7 groups). A few dopaminergic neurons retrogradely labeled with flurogold were observed in the periventricular area of the hypothalamus. Rare serotoninergic fluorogold labeled neurons belonged to the dorsal raphe nucleus. Most of these afferents came from both sides of the brain, except for hypothalamic supraoptic and paraventricular nuclei. In the light of these anatomical data, we compared our results with data obtained from rats, and we discussed the putative role of these afferents in sheep in the regulation of several specific functions in which the retrochiasmatic area may be involved, such as reproduction.
    Journal of Chemical Neuroanatomy 06/2000; · 2.48 Impact Factor
  • Source
    M Abramova, A Calas, J Thibault, M Ugrumov
    [show abstract] [hide abstract]
    ABSTRACT: In this study, we attempted to test whether tyrosine hydroxylase (TH), the first rate-limiting enzyme of catecholamine synthesis, is confined to the perikarya of activated magnocellular vasopressinergic (VPergic) neurons or is also present in their distal axons in the pituitary posterior lobe (PL). In addition, we evaluated the possible correlation between TH and VP turnover in the axons of rats drinking 2% NaCl for 1, 2, and 3 weeks. To this aim, we examined the large swellings of VPergic axons, the so-called Herring bodies, using the double-immunofluorescent technique and the avidinbiotin technique, combined with image analysis. Here we have demonstrated for the first time a colocalization of TH and VP in Herring bodies, which is a strong argument in favor of TH transport from the perikarya of VPergic neurons via axons toward their terminals. TH-immunoreactive (IR) and VP-IR materials were distributed in Herring bodies with seeming zonality. The number of VP-IR Herring bodies decreased by a factor of four over the first week of osmotic stimulation, remaining at almost the same low level until the end of the experiment. Conversely, the content of the VP-IR material within the individual Herring bodies fell gradually during the three weeks of salt-loading. The results suggest that VP depletion from Herring bodies prevails in its transport into these structures during the whole period of osmotic stimulation. In contrast to VP-IR Herring bodies, the number of TH-IR Herring bodies and the content of TH-IR material within the individual Herring bodies increased progressively during the entire experiment. The synchronization of the VP depletion and TH accumulation in Herring bodies during long-term osmotic stimulation raised the question about a possible functional interaction between both substances.
    Neural plasticity. 02/2000; 7(3):179-91.
  • [show abstract] [hide abstract]
    ABSTRACT: The dynamics of intracellular contents of vasopressin and tyrosine hydroxylase in neuron bodies were studied in the supraoptic nucleus and the distant segments of their axons in the posterior lobe of the hypophysis in rats in conditions of salt loading lasting one, two, and three weeks. The number of vasopressin-immununoreactive neurons increased by the end of the second week of osmotic stimulation, due to the onset of vasopressin synthesis in neurons not synthesizing this hormone in normal physiological conditions. The vasopressin concentration decreased in cell bodies and axons during the first two weeks of salt loading, apparently because vasopressin release occurred at a greater level than vasopressin synthesis. During the third week, the intracellular vasopressin content remained essentially constant, demonstrating the establishment of dynamic equilibrium between the synthesis and release of the hormone. The number of tyrosine hydroxylase-immunoreactive neurons and the levels of tyrosine hydroxylase in neuron bodies and axons, at least in the largest swellings (Herring bodies), gradually increased, demonstrating that the rate of tyrosine hydroxylase was greater than its rate of enzymatic degradation. Thus, chronic stimulation of vasopressin neurons was accompanied by a series of adaptive reactions, the most important of which appears to be the expression of vasopressin and tyrosine hydroxylase synthesis by neurons which do not normally synthesize these compounds.
    Neuroscience and Behavioral Physiology 01/2000; 30(6):617-24.
  • [show abstract] [hide abstract]
    ABSTRACT: The pyridoxal-5'-phosphate-dependent enzymes (B6 enzymes) are grouped into three main families named alpha, beta, and gamma. Proteins in the alpha and gamma families share the same fold and might be distantly related, while those in the beta family exhibit specific structural features. The rat aromatic L-amino acid decarboxylase (AADC; EC(4.1.1.28)) catalyzes the synthesis of two important neurotransmitters: dopamine and serotonin. It binds the cofactor pyridoxal-5'-phosphate and belongs to the alpha family. Despite the low level of sequence identity (approximately 10%) shared by the rat AADC and the sequences of the enzymes belonging to the B6 enzymes family, including the known three-dimensional structures, a multiple sequence alignment was deduced. A model was built using segments belonging to seven of the eleven known structures. By homology, and based on knowledge of the biochemistry of the aspartate aminotransferase, structurally and functionally important residues were identified in the rat AADC. Site-directed mutagenesis of the conserved residues D271, T246, and C311 was carried out in order to confirm our predictions and highlight their functional role. Mutation of D271A and D271N resulted in complete loss of enzyme activity, while the D271E mutant exhibited 2% of the wild-type activity. Substitution of T246A resulted in 5% of the wild-type activity while the C311A mutant conserved 42% of the wild-type activity. A functional model of the AADC is discussed in view of the structural model and the complementary mutagenesis and labelling studies.
    Proteins Structure Function and Bioinformatics 12/1999; 37(2):191-203. · 3.34 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: The pyridoxal-5´-phosphate-dependent enzymes (B6 enzymes) are grouped into three main families named α, β, and γ. Proteins in the α and γ families share the same fold and might be distantly related, while those in the β family exhibit specific structural features. The rat aromatic L-amino acid decarboxylase (AADC; EC(4.1.1.28)) catalyzes the synthesis of two important neurotransmitters: dopamine and serotonin. It binds the cofactor pyridoxal-5`-phosphate and belongs to the α family. Despite the low level of sequence identity (approximately 10%) shared by the rat AADC and the sequences of the enzymes belonging to the B6 enzymes family, including the known three-dimensional structures, a multiple sequence alignment was deduced. A model was built using segments belonging to seven of the eleven known structures. By homology, and based on knowledge of the biochemistry of the aspartate aminotransferase, structurally and functionally important residues were identified in the rat AADC. Site-directed mutagenesis of the conserved residues D271, T246, and C311 was carried out in order to confirm our predictions and highlight their functional role. Mutation of D271A and D271N resulted in complete loss of enzyme activity, while the D271E mutant exhibited 2% of the wild-type activity. Substitution of T246A resulted in 5% of the wild-type activity while the C311A mutant conserved 42% of the wild-type activity. A functional model of the AADC is discussed in view of the structural model and the complementary mutagenesis and labelling studies. Proteins 1999;37:191–203. ©1999 Wiley-Liss, Inc.
    Proteins Structure Function and Bioinformatics 10/1999; 37(2):191 - 203. · 3.34 Impact Factor
  • Doklady Akademii nauk / [Rossiĭskaia akademii nauk] 10/1999; 368(2):268-9.
  • [show abstract] [hide abstract]
    ABSTRACT: The olfactory bulb (OB) is involved in the processing of olfactory information particularly through the activation of its afferents. To localize their cell origin in sheep, a specific retrograde fluorescent tracer, Fluoro-Gold, was injected into the olfactory bulb of seven ewes. By using immunocytochemical techniques, retrogradely labeled neurons were colocalized with choline acetyltransferase, tyrosine hydroxylase, dopamine-beta-hydroxylase and serotonin to characterize cholinergic, noradrenergic and serotonergic Fluoro-Gold-labeled neurons. Most afferents originated from the ipsilateral side of the injection site. The OB received major inputs from the anterior olfactory nucleus (AON), the piriform cortex (PC), the olfactory tubercle, the diagonal band of Broca (DBB) and the amygdala. Other retrogradely labeled neurons were observed in the taenia tecta, the septum, the nucleus of the lateral olfactory tract, the preoptic area, the lateral hypothalamic area, the mediobasal hypothalamus, the lateral part of the premammillary nucleus, the paraventricular nucleus of the hypothalamus, the paraventricular thalamic nucleus, the central grey, the substantia nigra (SN), the ventral tegmental area (VTA), the lateral nucleus to the interpeduncular nucleus (IIP), the raphe and the locus coeruleus (LC). Contralateral labeling was also found in the AON, the PC, the SN compacta, the VTA, the IIP and the LC. Cholinergic Fluoro-Gold-labeled neurons belonged to the horizontal and vertical branch of the DBB. Noradrenergic afferents came from the LC and serotoninergic afferents came from the medial raphe nuclei and the 1IP. These data are discussed in relation with olfactory learning in the context of maternal behavior in sheep.
    Journal of Chemical Neuroanatomy 07/1999; 16(4):245-63. · 2.48 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: This study has evaluated the dynamic of intracellular vasopressin and tyrosine hydroxylase contents in the neuron cell bodies in the supraoptic nucleus and in the axons of the posterior lobe in rats drinking 2% NaCl for 1, 2, and 3 weeks. The number of vasopressin-immunoreactive neurons increased by the end of the second week of osmotic stimulation that might be explained by the onset of vasopressin synthesis in the neurons which do not synthesize this neurohormone under normal physiological conditions. The concentration of vasopressin fell down continuously during the first two weeks of salt-loading, apparently, due to predominance of the vasopressin release over its synthesis. Over the third week of salt-loading, the intracellular concentration of vasopressin was not changed significantly suggesting the establishment of the dynamic equilibrium between the vasopressin synthesis and release. The number of tyrosine hydroxylase-immunoreactive neurons and the amount of tyrosine hydroxylase in cell bodies and the large axonal swellings, Herring bodies, increased gradually showing that the rate of tyrosine hydroxylase synthesis prevailed over that of its enzymatic degradation. Thus, the chronic stimulation of vasopressin neurons is accompanied by a number of the adaptive reactions; the most important is related to the onset of vasopressin and tyrosine hydroxylase synthesis in the neurons which do not synthetize both of them under normal conditions.
    Rossiĭskii fiziologicheskiĭ zhurnal imeni I.M. Sechenova / Rossiĭskaia akademiia nauk 07/1999; 85(6):826-34.
  • [show abstract] [hide abstract]
    ABSTRACT: RANTES (regulated upon activation normal T expressed and secreted) is another member of the intercrine β subfamily which acts as a selective chemoattractant for human monocytes and CD4-positive lymphocytes and increases the adherence of monocytes to endothelial cells. In this work, the effect of RANTES was studied on rat skin injection sites. Rats were intradermally injected with 50 μl of RANTES, at different concentrations, fMet-Leu-Phe (FMLP), or LPS (positive controls) or PBS vehicle (negative control). The animals were then injected with 0·6 ml of Evans' blue in the tail vein in order to obtain a blue colour in the areas where the compounds were injected. After 4 h the rats were killed and the maximum diameter of the blue extravasation area was measured. The coloured areas were then excised and optical and electron microscopic studies were performed. In addition, in some of the excised tissue, a Northern blot analysis for histidine decarboxylase (HDC) mRNA was performed along with an estimation of the amount of histamine generated in the tissue injection sites. In these studies it was found that intradermal injections of 5, 2·5, and 1·25×10−5M RANTES produced a strong inflammatory response with the accumulation of a great number of basophil cells compared with the PBS (50 μl) negative control, or FMLP (10−6M/50 μl) or LPS (10 ng/50 μl) positive control, after 4 h. Moreover, 5, 2·5, 1·25×10−5M RANTES produced a dose–response stimulation of HDC mRNA in the tissues of skin injection sites. The increasing number of basophils in the RANTES inflamed tissues led to augmentation of histamine content, compared with the PBS control. In conclusion, the pro-inflammatory chemokine RANTES stimulates the generation of HDC mRNA in skin injection sites. © 1997 John Wiley & Sons, Ltd.
    The Journal of Pathology 04/1999; 183(3):352 - 358. · 7.59 Impact Factor
  • E Chaillou, G Tramu, J Thibault, Y Tillet
    [show abstract] [hide abstract]
    ABSTRACT: The distribution of tyrosine hydroxylase (TH) and of galanin immunoreactive (IR) neurons were examined in the sheep infundibular nucleus. Antisera raised against TH and galanin were used on adjacent sections and for double immunohistochemical staining of the same sections. There was considerable overlap in the distribution of TH and galanin-IR neurons in the medial part of the nucleus. Most of the galanin-IR neurons were also TH-IR, but less than 50% of the TH-IR neurons also expressed galanin immunoreactivity. Neurons immunoreactive to TH alone were observed close to the third ventricle and in the rostral part of the infundibular nucleus. In the median eminence, TH and galanin-IR fibres overlapped mainly in the lateral and dorsal parts of the external layer, but the colocalisation of both antigens could not be assessed on the available material. Thus, in sheep, the population of catecholaminergic neurons of the infundibular nucleus may be subdivided into different subpopulations according to their peptide content, but does not appear segregated as in rat and human.
    Journal of Chemical Neuroanatomy 11/1998; 15(4):251-9. · 2.48 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: To improve basic knowledge about the neurochemical organization of the urodele brain, and to study discrepancies in the localization of monoaminergic markers, we immunohistochemically charted the distribution of four such markers (tyrosine hydroxylase, aromatic L-amino acid decarboxylase, dopamine, and serotonin) in the axolotl (Ambystoma mexicanum) forebrain. Catecholaminergic and serotoninergic systems were found in similar locations to those seen in other Urodela. As seen in other vertebrates, the localization of the different monoaminergic markers reveals some inconsistencies. Cells that are exclusively tyrosine hydroxylase-immunoreactive are observed in the olfactory bulb, anterior olfactory nucleus/nucleus accumbens region, the epichiasmatic portion of the preoptic nucleus, and in the pars intercalaris thalami, whereas cells that are only labelled by aromatic L-amino acid decarboxylase are seen in the anterior olfactory nucleus/nucleus accumbens region, the bed nuclei of the anterior commissure, the posterior portion of the preoptic nucleus, the ventral hypothalamus, and the pars intercalaris thalami. The presence of cells solely serotonin (5-HT)-immunoreactive is suggested for the nucleus infundibularis dorsalis. Conversely, there were no areas that appeared to be exclusively immunoreactive for dopamine. Double-labelling for aromatic L-amino acid decarboxylase/tyrosine hydroxylase and aromatic L-amino acid decarboxylase/serotonin, together with cell counting, confirmed the existence of neurons that express only one monoaminergic marker in amphibian, supporting the hypothesis that these cells are universally present in the central nervous system of vertebrates.
    The Journal of Comparative Neurology 03/1998; 391(2):227-47. · 3.66 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: RANTES (regulated upon activation normal T expressed and secreted) is another member of the intercrine beta subfamily which acts as a selective chemoattractant for human monocytes and CD4-positive lymphocytes and increases the adherence of monocytes to endothelial cells. In this work, the effect of RANTES was studied on rat skin injection sites. Rats were intradermally injected with 50 microliters of RANTES, at different concentrations, fMet-Leu-Phe (FMLP), or LPS (positive controls) or PBS vehicle (negative control). The animals were then injected with 0.6 ml of Evans' blue in the tail vein in order to obtain a blue colour in the areas where the compounds were injected. After 4 h the rats were killed and the maximum diameter of the blue extravasation area was measured. The coloured areas were then excised and optical and electron microscopic studies were performed. In addition, in some of the excised tissue, a Northern blot analysis for histidine decarboxylase (HDC) mRNA was performed along with an estimation of the amount of histamine generated in the tissue injection sites. In these studies it was found that intradermal injections of 5, 2.5, and 1.25 x 10(-5) M RANTES produced a strong inflammatory response with the accumulation of a great number of basophil cells compared with the PBS (50 microliters) negative control, or FMLP (10(-6) M/50 microliters) or LPS (10 ng/50 microliters) positive control, after 4 h. Moreover, 5, 2.5, 1.25 x 10(-5) M RANTES produced a dose-response stimulation of HDC mRNA in the tissues of skin injection sites. The increasing number of basophils in the RANTES inflamed tissues led to augmentation of histamine content, compared with the PBS control. In conclusion, the pro-inflammatory chemokine RANTES stimulates the generation of HDC mRNA in skin injection sites.
    The Journal of Pathology 12/1997; 183(3):352-8. · 7.59 Impact Factor

Publication Stats

1k Citations
25 Downloads
269.55 Total Impact Points

Institutions

  • 2000–2005
    • Russian Academy of Medical Sciences
      Moskva, Moscow, Russia
  • 1980–2005
    • Collège de France
      Lutetia Parisorum, Île-de-France, France
  • 1997–2002
    • Université Paris-Est Créteil Val de Marne - Université Paris 12
      Créteil, Île-de-France, France
  • 1993–2001
    • Russian Academy of Sciences
      • • Institute of Developmental Biology
      • • Laboratory of Hormonal Regulations
      Moscow, Moscow, Russia
  • 1994–1999
    • French National Institute for Agricultural Research
      • Physiologie de la Reproduction et des Comportements (PRC)
      Castanet-Tolosan, Midi-Pyrenees, France
  • 1988–1999
    • French National Centre for Scientific Research
      Lutetia Parisorum, Île-de-France, France
  • 1995–1996
    • Università degli Studi G. d'Annunzio Chieti e Pescara
      Chieta, Abruzzo, Italy
  • 1984–1995
    • Pierre and Marie Curie University - Paris 6
      Lutetia Parisorum, Île-de-France, France
  • 1992
    • University of Bergen
      Bergen, Hordaland, Norway