References of "Lefebvre, P. P"
     in
Bookmark and Share    
Peer Reviewed
See detailExpression of Growth Factors and Their Receptors in the Postnatal Rat Cochlea
Malgrange, Brigitte ULg; Rogister, Bernard ULg; Lefebvre, P. P. et al

in Neurochemical Research (1998), 23(8), 1133-8

RT-PCR was used to assay for growth factors and receptors from seven different protein families in cochlea tissues of the juvenile rat. There was a broad representation of the growth factor families in ... [more ▼]

RT-PCR was used to assay for growth factors and receptors from seven different protein families in cochlea tissues of the juvenile rat. There was a broad representation of the growth factor families in all the cochlea tissues examined, though the organ of Corti and stria vascularis expressed a greater variety than the spiral ganglion. This broad expression suggests that a variety of known growth factors play significant roles in the development, maintenance, and repair of the inner ear. The results of this survey serve as a basis for the design of future in vitro experiments that will address the ability of growth factors to protect hair cells from damage and to evoke a repair-regeneration response by injured hair cells. [less ▲]

Detailed reference viewed: 16 (4 ULg)
Full Text
Peer Reviewed
See detailNt-3 Has a Tropic Effect on Process Outgrowth by Postnatal Auditory Neurones in Vitro
Malgrange, Brigitte ULg; Lefebvre, P. P.; Martin, Didier ULg et al

in Neuroreport (1996), 7(15-17), 2495-9

CONFOCAL analysis of early postnatal auditory neurones in a bicompartmental culture system was used to test for chemoattractant properties of NGF, BDNF and NT-3 on neuronal process outgrowth. NT-3 exerted ... [more ▼]

CONFOCAL analysis of early postnatal auditory neurones in a bicompartmental culture system was used to test for chemoattractant properties of NGF, BDNF and NT-3 on neuronal process outgrowth. NT-3 exerted a strong tropic effect on neuritic outgrowth from auditory neurones in this system. BDNF and NGF did not have any tropic activity that directed processes outgrowth from auditory neurones. However, BDNF was important for the support of neuronal survival in NGF-treated cultures and for neuritogenesis in NT-3-treated cultures. Since NT-3 has been identified as both a survival factor and a chemotropic agent for auditory neurones, it is likely that this neurotrophin will be a useful therapeutic agent in the treatment of damaged cochleae for the recovery of hearing. [less ▲]

Detailed reference viewed: 20 (0 ULg)
Peer Reviewed
See detailAstroglia-Released Factor Shows Similar Effects as Benzodiazepine Inverse Agonists
Rigo, Jean-Michel; Belachew, Shibeshih ULg; Lefebvre, P. P. et al

in Journal of Neuroscience Research (1994), 39(4), 364-76

Media conditioned by cultured neonatal cerebral cortex microexplants (CCM) or astrocytes (ACM) contain low molecular weight (< 1,000 Da) substance(s) which inhibits the gamma aminobutyric acid (GABA ... [more ▼]

Media conditioned by cultured neonatal cerebral cortex microexplants (CCM) or astrocytes (ACM) contain low molecular weight (< 1,000 Da) substance(s) which inhibits the gamma aminobutyric acid (GABA)-induced inward current recorded in cerebellar granule cells and hippocampal neurons in culture using the whole-cell patch-clamp technique. This effect is specific for CCM and ACM, as medium conditioned by PC12 cells (PC12CM) does not affect the GABA response of these cells. It is also specific for GABA-induced currents because glutamate-induced currents do not change either in amplitude or in shape in the presence of CCM or ACM. The inhibitory effect on the GABA response in cerebellar granule cells of both ACM and CCM could be suppressed by flumazenil, a specific benzodiazepine (BZD) antagonist and could be mimicked by two BZD inverse agonists. These data thus demonstrate the presence of a BZD inverse agonist-like activity in CCM and ACM. This effect of ACM on different neuronal cell types was heterogenous since no detectable effect could be observed on the GABA-induced current in GABA-responsive dorsal root ganglion (DRG) neurons, presumably reflecting a functional heterogeneity of the GABAA receptors present in these different neuronal subsets. By the release of such an endogenous BZD inverse agonist-like activity, glia cells could possibly modulate GABAA receptor-mediated responses. [less ▲]

Detailed reference viewed: 19 (5 ULg)
Full Text
Peer Reviewed
See detailPlasticity of Developing and Adult Dorsal Root Ganglion Neurons as Revealed in Vitro
Delree, P.; Ribbens, Clio ULg; Martin, Didier ULg et al

in Brain Research Bulletin (1993), 30(3-4), 231-7

We review recent data on the plasticity of dorsal root ganglion (DRG) neurons as revealed during cultivation in vitro. Some experiments on cultured developing DRG neurons and on adult DRG neurons in vivo ... [more ▼]

We review recent data on the plasticity of dorsal root ganglion (DRG) neurons as revealed during cultivation in vitro. Some experiments on cultured developing DRG neurons and on adult DRG neurons in vivo are also mentioned. Cultured developing and adult DRG neurons can be switched from an apolar to a multipolar phenotype by fetal calf serum or fibronectin. The effect is concentration dependent and occurs through an early modification of cell-substratum interaction. Adult DRG neurons synthesize and release within hours after injury TGF beta-1, which is a mitogen and a differentiation factor for Schwann cells. Finally, adult DRG neurons express in vitro neurotransmitters that are not expressed in vivo. This neurotransmitter plasticity can be modulated in vitro by some growth factors and in vivo by distal or proximal axotomy. [less ▲]

Detailed reference viewed: 37 (3 ULg)
Full Text
Peer Reviewed
See detailIn Vitro and in Vivo Modulation of 5-Hydroxytryptamine-, Thyrotropin-Releasing Hormone- and Calcitonin-Gene Related Peptide-Like Immunoreactivities in Adult Rat Sensory Neurons
Delree, P.; Martin, Didier ULg; Sadzot-Delvaux, Catherine ULg et al

in Neuroscience (1992), 51(2), 401-10

In a previous work we have shown that culturing adult rat dorsal root ganglia neurons modifies their neurotransmitter phenotype in such a way that cultured neurons synthesize transmitters that are not ... [more ▼]

In a previous work we have shown that culturing adult rat dorsal root ganglia neurons modifies their neurotransmitter phenotype in such a way that cultured neurons synthesize transmitters that are not found in situ, while several other transmitters are expressed in a much higher percentage of neurons in culture than in situ [Schoenen J. et al. (1989) J. Neurosci. Res. 22, 473-487]. The aim of the present study was to investigate the origin and the nature of the relevant environmental signals that allow this plasticity to be expressed, focusing on three neurotransmitters: 5-hydroxytryptamine, thyrotropin-releasing hormone and calcitonin-gene related peptide. The main results can be summarized as follows: (1) culturing cells in fetal calf serum or on feeder layers of astrocytes, Schwann cells or fibroblasts partially inhibits the serotoninergic phenotype of dorsal root ganglia neurons; (2) in vivo disconnection of dorsal root ganglia from their spinal targets but not from their peripheral or supraspinal targets induces a significant increase of the percentage of 5-hydroxytryptamine- and thyrotropin-releasing hormone-positive neurons in disconnected ganglia; (3) growth factors such as ciliary neuronotrophic factor or basic fibroblast growth factor but not nerve growth factor repress 5-hydroxytryptamine and calcitonin gene-related peptide immunoreactivity in cultured sensory neurons. In conclusion, neurotransmitter gene expression of adult dorsal root ganglia neurons is controlled by complex influences. Our data suggest that thyrotropin-releasing hormone and 5-hydroxytryptamine gene expression are tonically repressed in vivo by factors originating from the spinal segmental level and that growth factors such as ciliary neurotrophic factor or basic fibroblast growth factor could be potential vectors of this repressing effect. [less ▲]

Detailed reference viewed: 45 (25 ULg)
Full Text
Peer Reviewed
See detailTgf Beta 1 Expression Is Initiated in Adult Auditory Neurons by Sectioning of the Auditory Nerve
Lefebvre, P. P.; Martin, Didier ULg; Staecker, H. et al

in Neuroreport (1992), 3(4), 295-8

Neuronotrophic factors (e.g. basic fibroblast growth factor, bFGF and nerve growth factor, NGF) have been demonstrated to respectively promote survival and neuritogenesis in cultures of dissociated adult ... [more ▼]

Neuronotrophic factors (e.g. basic fibroblast growth factor, bFGF and nerve growth factor, NGF) have been demonstrated to respectively promote survival and neuritogenesis in cultures of dissociated adult rat spiral ganglia. Transforming growth factor beta (TGF beta 1) has been shown to modulate the response of cultured auditory neurons to bFGF through the induction of high affinity receptors for bFGF in the neurons. In this study, we show that TGF beta is expressed in situ by adult auditory neurons in response to traumatic injury (i.e. transection of the eighth cranial nerve). Based on these in vivo results and on the results from our previous in vitro studies, we propose that TFG beta 1 acts as an early autocrine signal involved in the response to injury by neurons of the peripheral auditor system. [less ▲]

Detailed reference viewed: 15 (1 ULg)
Peer Reviewed
See detailGrowth Factor Interactions in Cultures of Dissociated Adult Acoustic Ganglia: Neuronotrophic Effects
Lefebvre, P. P.; Van de Water, T. R.; Weber, T. et al

in Brain Research (1991), 567(2), 306-12

Auditory neurons cultured from adult rat acoustic ganglia require for survival either a substrate bound factor(s) present in astrocyte conditioned medium or substrate bound basic fibroblast growth factor ... [more ▼]

Auditory neurons cultured from adult rat acoustic ganglia require for survival either a substrate bound factor(s) present in astrocyte conditioned medium or substrate bound basic fibroblast growth factor (bFGF). Nerve growth factor (NGF) is not a survival factor for these neurons in vitro, but when used in combination with substrate bound bFGF, NGF does vigorously stimulate a neuritogenesis response by these neurons. Transforming growth factor beta (TGF beta 1) enhances the survival effect that bFGF has on these adult auditory neurons but does not by itself promote their survival in dissociated acoustic ganglion cultures. We propose that there may be complex interactions and synergy exerted by these growth factors (i.e. bFGF, NGF, TGF beta 1) during injury to the inner ear. [less ▲]

Detailed reference viewed: 2 (0 ULg)
Peer Reviewed
See detailTgf-beta1 Modulates bFGF Receptor Message Expression in Cultured Adult Auditory Neurons
Lefebvre, P. P.; Staecker, H.; Weber, T. et al

in Neuroreport (1991), 2(6), 305-8

Basic fibroblast growth factor (bFGF) has been shown to have neuronotrophic effects on cultured neurons. Transforming growth factor beta (TGFss1) has been implicated in the modulation of cellular ... [more ▼]

Basic fibroblast growth factor (bFGF) has been shown to have neuronotrophic effects on cultured neurons. Transforming growth factor beta (TGFss1) has been implicated in the modulation of cellular receptors for bFGF in several cell types. In this study, we show that TGFss1 is expressed in cultured adult mouse auditory neurons in response to explanation injury and acts in an autocrine fashion to increase the level of expression of bFGF receptors message in these same neurons. Based on these in-vitro results, we propose that these trophic factors (i.e. TGFss1 and bFGF) play a significant role in the response to injury by the mature auditory system. [less ▲]

Detailed reference viewed: 7 (0 ULg)
See detailNeurono-Glial Interactions and Neural Plasticity
Moonen, Gustave ULg; Rogister, Bernard ULg; Leprince, Pierre ULg et al

in Coleman, Paul; Higgins, G.; Phelps, C. (Eds.) Progress In Brain research: Neuronal Plasticity in aging and dementia (1990)

Detailed reference viewed: 15 (2 ULg)