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Dive into the research topics where Danielle Jaillard is active.

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Featured researches published by Danielle Jaillard.


Neuroreport | 1990

Protein kinases, nitric oxide and long-term depression of synapses in the cerebellum

F. Crepel; Danielle Jaillard

We have analysed the effects of polymyxin B, a potent inhibitor of calcium-dependent protein kinases, of L-N-monomethylarginine, an inhibitor of nitric oxide synthesis, and of methylene blue which prevents activation of soluble guanylate cyclase, on long-term depression of parallel fibre-mediated EPSPs of rat cerebellar Purkinje cells in slices maintained in-vitro. In control conditions, a long-term depression of parallel fibre-mediated EPSPs was consistently induced by their pairing with calcium spikes directly elicited in the postsynaptic cells. This long-term change in synaptic strength was not observed in the presence of polymyxin B, of L-N-monomethylarginine, or of methylene blue, suggesting that calcium-dependent protein kinases and nitric oxide are both involved.


European Journal of Neuroscience | 1993

Long‐term Depression Requires Nitric Oxide and Guanosine 3′:5’Cyclic Monophosphate Production in Rat Cerebellar Purkinje Cells

Hervé Daniel; N. Hemart; Danielle Jaillard; F. Crepel

In patch‐clamped Purkinje cells, bath application of the nitric oxide synthase inhibitor NG‐methyl‐l‐arginine consistently prevents the induction of long‐term depression (LTD) of parallel fibre‐mediated excitatory postsynaptic potentials (EPSPs) induced by their pairing with calcium spikes. On the other hand, bath application of nitric oxide donors and of 8‐bromoguanosine 3′:5’cyclic monophosphate is able to reproduce an LTD‐like phenomenon. LTD of parallel fibre‐mediated EPSPs also occurs when nitric oxide donors or guanosine 3′:5’cyclic monophosphate are directly dialysed into Purkinje cells, and this effect partially occludes LTD induced by pairing protocols. These results show that nitric oxide does play a role in LTD induction, and demonstrate for the first time that its site of action is probably the soluble guanylate cyclase of Purkinje cells.


Experimental Brain Research | 1992

Coactivation of metabotropic glutamate receptors and of voltage-gated calcium channels induces long-term depression in cerebellar Purkinje cells in vitro.

Hervé Daniel; N. Hemart; Danielle Jaillard; F. Crepel

SummaryUsing an in vitro slice preparation, we studied the effects, on parallel fiber (PF)-mediated EPSPs, of coactivation of metabotropic-glutamate receptors and of voltage-gated calcium (Ca) channels of Purkinje cells (PCs) by bath application of 50 μM trans-1-aminocyclopentyl-1,3-dicarboxylate (trans-ACPD) and by direct depolarization of the cells, respectively. These effects were compared with changes in synaptic efficacy obtained when α-amino-3hydroxy-5-methylisoxalone-4-propionate (AMPA) receptors of PCs were also activated through stimulation of PFs during the pairing protocol, as well as when similar experiments were performed without trans-ACPD in the bath. In a control medium, pairing for 1 min of PF-mediated EPSPs evoked at 1 Hz with Ca spikes evoked by steady depolarization of PCs (n = 13) led to LTD of synaptic transmission in 9 cases whereas for the others EPSPs were not affected. No LTD occurred in 9 out of 10 other cells tested when PF stimulation was omitted during the 1 min period of Ca spike firing of PCs. Bath application of 50 μM trans-ACPD, in conjunction with the same pairing protocol as before (n = 8), led to a significantly larger LTD of PF-mediated EPSPs after washing out of this drug. Moreover, a clearcut LTD of PF-mediated EPSPs was also observed in 5 of the 8 other cells, when PF stimulation was omitted during Ca spike firing in the presence of trans-ACPD. As trans-ACPD alone induced fully reversible depressions of EPSPs, coactivation of metabotropic-glutamate receptors and of voltage-gated Ca channels is therefore likely to be sufficient to induce LTD of PF-mediated EPSPs.


European Journal of Neuroscience | 1995

RECEPTORS AND SECOND MESSENGERS INVOLVED IN LONG-TERM DEPRESSION IN RAT CEREBELLAR SLICES IN VITRO : A REAPPRAISAL

Nathalie Hémart; Hervé Daniel; Danielle Jaillard; F. Crepel

In patch‐clamped Purkinje cells (PCs), bath application of the ionotropic glutamate receptor antagonist, 6‐cyano‐7‐nitroquinoxaline‐2,3‐dione (CNQX) prevents induction of long‐term depression (LTD) of parallel fibre (PF)‐mediated EPSPs by a pairing protocol between Ca2+ spike firing and PF stimulation whereas bath application of (RS)‐α‐methyl‐4‐carboxyphenylglycine (MCPG), a metabotropic glutamate (mGLU) receptor antagonist, does not. On the other hand, LTD can be also induced by pairing direct depolarization of PCs with activation of mGLU receptors by 1 S,3R‐aminocyclopentyl‐dicarboxylate (1S, 3R‐ACPD), even in the presence of CNQX. In this case, LTD induction is not consistently blocked by bath application of the nitric oxide synthase inhibitor, NG‐methyl‐l‐arginine (l‐NMMA), whereas it is strongly blocked when the protein kinase C inhibitor peptide 19‐36 is dialysed into PCs. These results are at variance with LTD induced by a pairing protocol between Ca2+ spikes and PF‐mediated EPSPs which depends to the same extent on both cascades. Finally, thapsigargin, which depletes most intracellular Ca2+ pools, does not block induction of LTD by a pairing protocol between Ca2+ spikes and PF‐mediated EPSPs whereas it prevents the induction of LTD depending on strong mGLU receptor activation.


Experimental Brain Research | 1991

Effects of ACPD and AP3 on parallel-fibre-mediated EPSPs of Purkinje cells in cerebellar slices in vitro

F. Crepel; Hervé Daniel; N. Hemart; Danielle Jaillard

SummaryThe effects of trans-1-amino-cyclopentyl-1,3-dicarboxylate (trans-ACPD) and of DL-2-amino-3-phosphonopropionic acid (AP3), i.e. selective agonist and antagonist of metabotropic quisqualate receptors respectively, on parallel fibre (PF)-mediated EPSPs of Purkinje cells (PCs) were studied in an in vitro slice preparation. Bath application of 500 μM trans-ACPD in conjunction with PF stimulation at 0.2 or 1 Hz depending on the cell always induced a marked depression of PF-mediated EPSPs, which was fully reversible in most cases after wash-out of this compound. Trans-ACPD also often induced a transient depolarization of PCs which induced calcium spike firing in these cells and which again no longer persisted after wash-out of trans-ACPD. Even in cells which were depolarized by trans-ACPD, the decrease in amplitude of PF-mediated EPSPs started before the appearence of calcium spikes, lasted longer than the transient depolarizing effect of trans-ACPD, and was accompanied by no variation in input resistance of the cells when they were manually clamped at their initial resting potential. Bath application of 600 μM DL-AP3 had no effect on PF-mediated EPSPs or the bioelectrical activities of PCs. Moreover, it did not prevent the effects of trans-ACPD mentioned before. The present results are not consistent with the view that coactivation of ionotropic and metabotropic quisqualate receptors of PCs is sufficient to induce a long-term depression of PF-mediated EPSPs.


Neuroscience Research | 1994

Properties of glutamate receptors are modified during long-term depression in rat cerebellar Purkinje cells

N. Hemart; Hervé Daniel; Danielle Jaillard; F. Crepel

Long-term depression (LTD) of synaptic transmission at parallel fiber (PF)-Purkinje cell (PC) synapses occurs when these synapses are activated in conjunction with direct activation of voltage-gated calcium (Ca2+) channels of PCs. In the present study, we have used Aniracetam to test whether the expression of LTD at PF-PC synapses is due to a genuine modification of properties of alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionate (AMPA) receptors of these neurons. Whole-cell recordings of PF-mediated EPSCs were performed in thin slices taken from 16-22-day-old rats. In all tested cells, bath application of Aniracetam potentiated PF-mediated EPSCs and prolonged their decay without notably changing their rising phase. On the other hand, Aniracetam prevented the induction of LTD by a pairing protocol with Ca2+ spikes and, conversely, the nootropic compound had a larger potentiating effect on PF-mediated EPSCs during expression of LTD than normally, when this change in synaptic efficacy had been induced prior to Aniracetam application. These data strongly suggest that LTD involves a desensitization of postsynaptic AMPA receptors at PF-PC synapses, or, at least, a change in their functional characteristics.


Neuropharmacology | 1994

Cellular locus of the nitric oxide-synthase involved in cerebellar long-term depression induced by high external potassium concentration

F. Crepel; E. Audinat; Hervé Daniel; N. Hemart; Danielle Jaillard; Jean Rossier; Bertrand Lambolez

The cellular location of the NO-synthase involved in long-term depression (LTD) of parallel fiber (PF)-mediated EPSCs induced by raising the external potassium (K) concentration has been investigated by using both whole-cell patch-clamp recordings (WCR) of Purkinje cells (PCs) in thin slices in vitro, and reverse transcription followed by polymerase chain reaction (PCR) applied to mRNAs harvested from these single PCs during WCR. In all tested cells in the control group, a large LTD of PF-mediated EPSCs was induced by perfusing the slices for 3 min with a high (30 mM) K perfusing medium. In a second group of cells for which the protein kinase C (PKC) inhibitor peptide 19-36 was added to the intrapipette solution at a concentration of 10 microM, the LTD following complete wash out of the high K solution was significantly less prominent than in the control group. Very similar results were also obtained when 30 microM NG-methyl-L-arginine (L-NMMA) was added to the perfusing medium. In contrast, when both the PKC inhibitor peptide 19-36 and L-NMMA were added to the intrapipette solution at a concentration of 10 and 30 microM respectively, no LTD was revealed following wash out of the high K solution. Finally, the PCR amplification of mRNAs harvested from these single PCs during WCR, as well as from granule cells from the same slices, confirms that mRNAs encoding the NO-synthase are expressed by granule cells, whereas they are not detected in PCs.


Journal of Hazardous Materials | 2012

Quantitative evaluation of multi-walled carbon nanotube uptake in wheat and rapeseed

Camille Larue; Mathieu Pinault; Bertrand Czarny; Dominique Georgin; Danielle Jaillard; Nedjma Bendiab; Martine Mayne-L’Hermite; Frédéric Taran; Vincent Dive; Marie Carrière

Environmental contamination with carbon nanotubes would lead to plant exposure and particularly exposure of agricultural crops. The only quantitative exposure data available to date which can be used for risk assessment comes from computer modeling. The aim of this study was to provide quantitative data relative to multi-walled carbon nanotube (MWCNT) uptake and distribution in agricultural crops, and to correlate accumulation data with impact on plant development and physiology. Roots of wheat and rapeseed were exposed in hydroponics to uniformly (14)C-radiolabeled MWCNTs. Radioimaging, transmission electron microscopy and raman spectroscopy were used to identify CNT distribution. Radioactivity counting made it possible absolute quantification of CNT accumulation in plant leaves. Impact of CNTs on seed germination, root elongation, plant biomass, evapotranspiration, chlorophyll, thiobarbituric acid reactive species and H(2)O(2) contents was evaluated. We demonstrate that less than 0.005‰ of the applied MWCNT dose is taken up by plant roots and translocated to the leaves. This accumulation does not impact plant development and physiology. In addition, it does not induce any modifications in photosynthetic activity nor cause oxidative stress in plant leaves. Our results suggest that if environmental contamination occurs and MWCNTs are in the same physico-chemical state than the ones used in the present article, MWCNT transfer to the food chain via food crops would be very low.


Biomaterials | 2010

The performance of PEGylated nanocapsules of perfluorooctyl bromide as an ultrasound contrast agent

Raquel Díaz-López; Nicolas Tsapis; Mathieu Santin; S. Bridal; Valérie Nicolas; Danielle Jaillard; Danielle Libong; Pierre Chaminade; Véronique Marsaud; Christine Vauthier; Elias Fattal

The surface of polymeric nanocapsules used as ultrasound contrast agents (UCAs) was modified with PEGylated phospholipids in order to escape recognition and clearance by the mononuclear phagocyte system and achieve passive tumor targeting. Nanocapsules consisted of a shell of poly(lactide-co-glycolide) (PLGA) encapsulating a liquid core of perfluorooctyl bromide (PFOB). They were decorated with poly(ethylene glycol-2000)-grafted distearoylphosphatidylethanolamine (DSPE-PEG) incorporated in the organic phase before the solvent emulsification-evaporation process. The influence of DSPE-PEG concentration on nanocapsule size, surface charge, morphology, hydrophobicity and complement activation was evaluated. Zeta potential measurements, Hydrophobic interaction chromatography and complement activation provide evidence of DSPE-PEG presence at nanocapsule surface. Electronic microscopy reveals that the core/shell structure is preserved up to 2.64 mg of DSPE-PEG for 100 mg PLGA. In vivo ultrasound imaging was performed in mice bearing xenograft tumor with MIA PaCa-2 cells, either after an intra-tumoral or intravenous injection of nanocapsules. Tumor was observed only after the intra-tumoral injection. Despite the absence of echogenic signal in the tumor after intravenous injection of nanocapsules, histological analysis reveals their accumulation within the tumor tissue demonstrating that tissue distribution is not the unique property required for ultrasound contrast agents to be efficient.


Pharmaceutical Research | 2003

Visualization of Insulin-Loaded Nanocapsules: In Vitro and in Vivo Studies After Oral Administration to Rats

Huguette Pinto-Alphandary; Malam Aboubakar; Danielle Jaillard; Patrick Couvreur; Christine Vauthier

AbstractPurpose. Biodegradable poly(isobutylcyanoacrylate) nanocapsules have been recognized as a promising carrier for oral administration of peptides and proteins. In the present study, we investigate the fate of insulin-loaded nanocapsules by fluorescence and transmission electron microscopy (TEM) after intragastric force-feeding to rats. Methods. Insulin-, Texas-red®-labeled insulin, or gold-labeled insulin-loaded nanocapsules were first characterized. Rats received a single dose of nanocapsules (diameter 60-300 nm, 57 IU insulin/kg) by intragastric force-feeding. After 90 min, ileum was isolated and prepared for fluorescence and transmission electron microscopy. Results. Nanocapsules were observed on both sides of the gut epithelium and in blood capillaries. In M-cell-free epithelium, apparently intact nanocapsules could be seen in the underlying tissue, suggesting they could cross the epithelium and carry the encapsulated peptide. In M-cell-containing epithelium, nanocapsules appeared degraded in the vicinity of macrophages. It is noteworthy that intestinal absorption of nanocapsules was observed without artifacts forcing the nanocapsules to stay in the gut. Conclusions. Based on TEM observations, this study shows the intestinal absorption of biodegradable nanocapsules leading to the transport of insulin across the epithelium mucosa. The fate of the nanocapsules appeared different depending on the presence or the absence of M cells in the intestinal epithelium.

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F. Crepel

University of Paris-Sud

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N. Hemart

University of Paris-Sud

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Marie Carrière

Centre national de la recherche scientifique

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Camille Larue

Centre national de la recherche scientifique

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