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1.
C. Goetz S. Bourgoin F. Cesselin A. Brandi D. Bression M. Martinet F. Peillon M. Hamon 《Neurochemistry international》1983,5(4):375-383
The subcutaneous implantation of an estradiol pellet (10 mg) into female rats induced a hypophyseal hyperplasia with hyperprolactinaemia. Examination of neurotransmitter receptors in the hippocampus, striatum and cerebral cortex one month after the implantation revealed that estrogenization was associated with: an increased density of 3H-domperidone binding sites (D2 receptors) in the striatum and reduced numbers of 3H-serotonin high affinity sites (5-HT1 receptors) in the hippocampus and of 3H-muscimol binding sites (GABA receptors) in the hippocampus, striatum and cerebral cortex. In contrast, the characteristics of 3H-spiperone binding to 5-HT2 receptors (in the cerebral cortex) and those of 3H-flunitrazepam binding to benzodiazepine sites (in the three brain regions examined) were not significantly different in estrogenized and in control female rats. However, the enhancing effect of GABA on 3H-flunitrazepam binding was markedly reduced in brain membranes from estrogenized animals. The respective roles of estradiol and prolactin in mediating these changes in neurotransmitter receptors are discussed notably with regard to the regional heterogeneity of estradiol binding capacity in the rat brain. 相似文献
2.
FEEDBACK REGULATION OF 5-HT SYNTHESIS IN RAT STRIATAL SLICES 总被引：1，自引：2，他引：1
The effects of changes in intraneuronal levels of 5-HT induced by monoamine oxidase inhibitors (MAOI) given in vivo or exogenous 5-HT added in vitro on 5-HT synthesis in striatal slices of the rat have been examined. The synthesis of 5-HT was estimated by the measurement of the total formation of [3H]5-HT and [3H]5-hydroxyindole acetic acid from [3H]tryptophan and by calculation of the conversion index (CI) of tryptophan into 5-HT. The small formation of [3H]tryptamine and [3H]indole acetic acid from [3H]tryptophan was taken into account in the estimation of 5-HT synthesis. Both MAOI pretreament (180 min) and 5-HT (2·8 μM) inhibited synthesis. The latter effect persisted in catecholamine depleted tissues and was related to intraneuronal changes in 5-HT levels, since it could be prevented by chlorimipramine. The inhibition of 5-HT synthesis was related to the decreased conversion of tryptophan into 5-hydroxytryptophan and could not be prevented by p-chloro-phenylalanine pretreatment which depleted 5-HT levels or by dibutyryl cyclic AMP which normally stimulated 5-HT synthesis. Tryptophan uptake in slices was not affected by exogenous 5-HT. The various mechanisms possibly involved in the end product regulation process of 5-HT synthesis are discussed. 相似文献
3.
4.
Toufic Akl;Gilles Bourgoin;Marie-Line Souq;Joël Appolinaire;Marie-Thérèse Poirel;Philippe Gibert;Georges Abi Rizk;Mathieu Garel;Lionel Zenner 《Parasite (Paris, France)》2019,26(1)
Ticks are important vectors of several human and animal pathogens. In this study, we estimated the prevalence of important tick-borne infections in questing ticks from an area in Southwestern France (Hautes-Pyrénées) inhabited by Pyrenean chamois (Rupicapra pyrenaica pyrenaica ) experiencing high tick burden. We examined adult and nymph ticks collected by the flag dragging method from 8 to 15 sites in the Pic de Bazès during the years 2009, 2011, 2013 and 2015. PCR assays were conducted on selected ticks for the detection of Borrelia burgdorferi s.l., Babesia spp., Rickettsia spp., spotted fever group (SFG) Rickettsia and Anaplasma phagocytophilum . Randomly selected positive samples were submitted for sequence analysis. A total of 1971 questing ticks were collected including 95 males, 101 females and 1775 nymphs. All collected ticks were identified as Ixodes ricinus. Among them, 696 ticks were selected for pathogen detection and overall prevalence was 8.4% for B. burgdorferi s.l.; 0.4% for Babesia spp.; 6.1% for A. phagocytophilum ; 17.6% for Rickettsia spp.; and 8.1% for SFG Rickettsia . Among the sequenced pathogens, we detected in this population of ticks the presence of Babesia sp. EU1 and Rickettsia helvetica , as well as Rickettsia monacensis for the first time in France. The detection of these pathogens in the Pic de Bazès highlights the potential infection risks for visitors to this area and the Pyrenean chamois population. 相似文献
5.
Martin G. Houle Sylvain Bourgoin 《Biochimica et Biophysica Acta (BBA)/Molecular and Cell Biology of Lipids》1999,1439(2):135-150
The rapid production of phosphatidic acid following receptor stimulation has been demonstrated in a wide range of mammalian cells. Virtually every cell uses phosphatidylcholine as substrate to produce phosphatidic acid in a controlled reaction catalyzed by specific PLD isoforms. Considerable effort has been directed at studying the regulation of PLD activities and subsequent work has characterized a family of proteins including PLD1 and PLD2. Whereas both PLD enzymes are dependent on phosphatidylinositol 4,5-bisphosphate for activity only the PLD1 isoform was strongly stimulated by the small GTPases ARF and RhoA and by protein kinase Cα as well. A role for tyrosine kinase activities in the membrane recruitment of small GTPases, in the synthesis of phosphatidylinositol 4,5-bisphosphate and tyrosine phosphorylation of PLD1 and PLD2 has been uncovered. However, it still not clear exactly how tyrosine phosphorylation of proteins contributes to PLD activation in cells. Here we review the data linking tyrosine phosphorylation of proteins to the activation of PLD and describe recent finding on the sites and possible mechanisms of action of tyrosine kinases in receptor-mediated PLD activation. Finally, a model illustrating the potential complex interplay linking these signaling events with the activation of PLD is presented. 相似文献
6.
Herpes Simplex Virus 1-Mediated Transfer of Preproenkephalin A in Rat Dorsal Root Ganglia 总被引：1，自引：0，他引：1
João Manuel Antunes Bras Alberto L. Epstein Sylvie Bourgoin Michel Hamon François Cesselin Michel Pohl 《Journal of neurochemistry》1998,70(3):1299-1303
Abstract: Recombinant herpes simplex virus-1 encoding the rat preproenkephalin A (HSVLatEnk1 ) was generated for driving the expression of preproenkephalin A-derived peptides in dorsal root ganglia of rats in vivo. Three weeks after infection via the hind footpads, quantitative RT-PCR and in situ hybridization experiments showed a strong expression of preproenkephalin A mRNA in lumbar dorsal root ganglia. In addition, a 40–160% increase in radioimmunoassayable Met-enkephalin-like material concentrations was found in the dorsal spinal cord and dorsal root ganglia, respectively, at the lumbar level in HSVLatEnk1 -infected rats as compared with animals infected with β-galactosidase-encoding recombinant herpes simplex virus-1 or control rats. These data demonstrate the efficacy of the preproenkephalin A encoding vector and suggest that it should help in elucidating the role of Met-enkephalin-containing primary afferent fibers in pain transmission and/or control. 相似文献
7.
Abstract: Under control conditions, superfused slices of the dorsal half of the lumbar enlargement from adult rats released Met-enkephalin-like material (MELM) that behaved as authentic Met-enkephalin under two different chromatographic procedures (Bio-gel filtration, HPLC). MELM release increased markedly on exposure of slices to batrachotoxin (0.5 μ M ) or to an excess of K+ (28 and 56 m M instead of 5.6 m M ). The K + -evoked release was totally dependent on the presence of Ca2+ in the super-fusing fluid whereas the spontaneous efflux of MELM was only partially Ca2+ -dependent. Further experiments performed with tissues of polyarthritic rats indicated that the increase in their MELM levels was associated with a lower fractional rate constant of MELM release, therefore suggesting that spinal Met-enkephalin turnover might be reduced in chronically suffering animals. Examination of the possible modulation of MELM release by various neuroactive compounds present within the dorsal horn revealed that cholecystokinin (10 μ M ), but not its desulphated derivative, substance P-sulphoxide (10 μ M ), and to a lesser extent substance P, enhanced the K+ -evoked MELM release. In contrast, γ-aminobutyric acid (10 μ M ) and (–)-baclofen (1 μ M ) partially prevented the stimulatory effect of K+ on MELM release. Other compounds such as serotonin, somatostatin, and neurotensin altered neither the spontaneous nor the K+ -evoked release of MELM. 相似文献
8.
Charlotte Bourgoin;Christophe Barbraud;Tobie Getti;Karine Delord;Frédéric Angelier;Aymeric Bodin;Pierrick Blanchard; 《Ecology and evolution》2024,14(9):e70174
Parental investment increases offspring fitness at the expense of the parent's ability to invest in other offspring. In many animal species, parents guard their offspring after birth. The parental decision over the duration of this period is expected to be triggered by the associated fitness costs and benefits for both offspring and parents. Here, we evaluated the relevance of several intrinsic and environmental variables in determining brooding period duration in the wandering albatross (Diomedea exulans) and questioned whether brooding duration was related to chick subsequent survival and biometry prior to fledging. We used a semi-experimental design to increase the variance in cat abundance, a recent predator of albatross chicks, and predicted that an increased predation risk at the nest scale would trigger longer chick brooding and thus, protection. In addition, we questioned the influence of weather conditions, hatching date, and characteristics of chicks (sex and biometry) and parents (sex and age) on brooding duration. We report no effect of predation risk or parental characteristics on brooding duration. However, the probability for a parent to end brooding decreased with forthcoming unfavorable weather. Our data also revealed reduced brooding duration for late-hatched chicks and a positive association between brooding duration and chick structural size, and between the frequency of shifts between parents and chick structural size. Finally, brooding duration was not associated with chick survival or with chick biometry prior to fledging. We discuss these results in light of pre-existing hypotheses on fitness costs and benefits associated with brooding duration for chicks and parents. 相似文献
9.
Gilquin B Bourgoin M Ménez R Le Du MH Servent D Zinn-Justin S Ménez A 《Protein science : a publication of the Protein Society》2003,12(2):266-277
Animal toxins are small proteins built on the basis of a few disulfide bonded frameworks. Because of their high variability in sequence and biologic function, these proteins are now used as templates for protein engineering. Here we report the extensive characterization of the structure and dynamics of two toxin folds, the \"three-finger\" fold and the short alpha/beta scorpion fold found in snake and scorpion venoms, respectively. These two folds have a very different architecture; the short alpha/beta scorpion fold is highly compact, whereas the \"three-finger\" fold is a beta structure presenting large flexible loops. First, the crystal structure of the snake toxin alpha was solved at 1.8-A resolution. Then, long molecular dynamics simulations (10 ns) in water boxes of the snake toxin alpha and the scorpion charybdotoxin were performed, starting either from the crystal or the solution structure. For both proteins, the crystal structure is stabilized by more hydrogen bonds than the solution structure, and the trajectory starting from the X-ray structure is more stable than the trajectory started from the NMR structure. The trajectories started from the X-ray structure are in agreement with the experimental NMR and X-ray data about the protein dynamics. Both proteins exhibit fast motions with an amplitude correlated to their secondary structure. In contrast, slower motions are essentially only observed in toxin alpha. The regions submitted to rare motions during the simulations are those that exhibit millisecond time-scale motions. Lastly, the structural variations within each fold family are described. The localization and the amplitude of these variations suggest that the regions presenting large-scale motions should be those tolerant to large insertions or deletions. 相似文献
10.
J. C. Fox Y. M. Buckley F. D. Panetta J. Bourgoin D. Pullar 《Diversity & distributions》2009,15(4):577-589
Aim To develop a surveillance support model that enables prediction of areas susceptible to invasion, comparative analysis of surveillance methods and intensity and assessment of eradication feasibility. To apply the model to identify surveillance protocols for generalized invasion scenarios and for evaluating surveillance and control for a context‐specific plant invasion. Location Australia. Methods We integrate a spatially explicit simulation model, including plant demography and dispersal vectors, within a Geographical Information System. We use the model to identify effective surveillance protocols using simulations of generalized plant life‐forms spreading via different dispersal mechanisms in real landscapes. We then parameterize the surveillance support model for Chilean needle grass [CNG; Nassella neesiana (Trin. & Rupr.) Barkworth], a highly invasive tussock grass, which is an eradication target in south‐eastern Queensland, Australia. Results General surveillance protocols that can guide rapid response surveillance were identified; suitable habitat that is susceptible to invasion through particular dispersal syndromes should be targeted for surveillance using an adaptive seek‐and‐destroy method. The search radius of the adaptive method should be based on maximum expected dispersal distances. Protocols were used to define a surveillance strategy for CNG, but simulations indicated that despite effective and targeted surveillance, eradication is implausible at current intensities. Main conclusions Several important surveillance protocols emerged and simulations indicated that effectiveness can be increased if they are followed in rapid response surveillance. If sufficient data are available, the surveillance support model should be parameterized to target areas susceptible to invasion and determine whether surveillance is effective and eradication is feasible. We discovered that for CNG, regardless of a carefully designed surveillance strategy, eradication is implausible at current intensities of surveillance and control and these efforts should be doubled if they are to be successful. This is crucial information in the face of environmentally and economically damaging invasive species and large, expensive and potentially ineffective control programmes. 相似文献