Papers by Emmanuel Richard
Frontiers in behavioral neuroscience, 2014
A disruption of the vitamin A signaling pathway has been involved in age-related memory decline a... more A disruption of the vitamin A signaling pathway has been involved in age-related memory decline and hippocampal plasticity alterations. Using vitamin A deficiency (VAD), a nutritional model leading to a hyposignaling of the retinoid pathway, we have recently demonstrated that retinoic acid (RA), the active metabolite of vitamin A, is efficient to reverse VAD-induced spatial memory deficits and adult hippocampal neurogenesis alterations. Besides, excess of glucocorticoids (GCs) occurring with aging is known to strongly inhibit hippocampal plasticity and functions and few studies report on the counteracting effects of RA signaling pathway on GCs action. Here, we have addressed whether the modulation of brain GCs availability could be one of the biological mechanisms involved in the effects of vitamin A status on hippocampal plasticity and functions. Thus, we have studied the effects of a vitamin A-free diet for 14 weeks and a 4-week vitamin A supplementation on plasma and hippocampal ...
Journal of Endocrinology, 2013
The aim of this study was to explore the involvement of retinoids in the hypoactivity and hyporea... more The aim of this study was to explore the involvement of retinoids in the hypoactivity and hyporeactivity to stress of the hypothalamic–pituitary–adrenal (HPA) axis in LOU/C rats. We measured the effects of vitamin A deficiency administered or not with retinoic acid (RA) on plasma corticosterone in standard conditions and in response to restraint stress and on hypothalamic and hippocampal expression of corticosteroid receptors, corticotropin-releasing hormone and 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) in LOU/C rats. Interestingly, under control conditions, we measured a higher plasma concentration of retinol in LOU/C than in Wistar rats, which could contribute to the lower basal activity of the HPA axis in LOU/C rats. Vitamin A deficiency induced an increased HPA axis activity in LOU/C rats, normalized by RA administration. Compared with LOU/C control rats, vitamin A-deficient rats showed a delayed and heightened corticosterone response to restraint stress. The expression...
Annales des Mines - Réalités industrielles, 2010
Internet et les nouveaux langages de la relation client Internet est devenu un espace où le « con... more Internet et les nouveaux langages de la relation client Internet est devenu un espace où le « consomm-acteur » s'adresse au consommateur. Les marques ne peuvent pas rester à l'écart de ces échanges et s'organisent pour réinvestir le Web. Un espace à vivre s'organise et des codes d'échange et de bonne conduite doivent encore être créés… par Emmanuel RICHARD* QUELQUES EXEMPLES DE RÉVOLUTIONS RÉALITÉS INDUSTRIELLES • NOVEMBRE 2010
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Papers by Emmanuel Richard