Collège de France

About: Collège de France is a education organization based out in Paris, France. It is known for research contribution in the topics: Population & Receptor. The organization has 6541 authors who have published 11983 publications receiving 648742 citations. The organization is also known as: College de France.

Activation of the hippocampal formation by vestibular stimulation: A functional magnetic resonance imaging study

Abstract: Functional MRI (f-MRI) is a non-invasive technique developed to permit functional mapping of the brain with a better temporal and spatial resolution than that offered by PET techniques. In our study, f-MRI was performed using blood oxygenation level dependent (BOLD) contrast imaging based on the magnetic properties of hemoglobin. This method relies on changes in the blood supply to the brain that accompany sensory stimulation or changes in cognitive state. All the images were obtained at 1.5 T on a Signa GEMS without ultrafast imaging. The vestibular stimulation was cold irrigation of the external auditory meatus (caloric stimulation). A population of normal healthy volunteers without a history of vestibular dysfunction was studied. The hippocampal formation as well as the retrosplenial cortex and the subiculum were activated by vestibular stimulation, suggesting that this activation may be related to spatial disorientation and a sensation of self-rotation experienced by the subjects during vestibular stimulation. The other results are similar to those obtained using PET.

Physical and Functional Interactions between Cellular Retinoic Acid Binding Protein II and the Retinoic Acid-Dependent Nuclear Complex

Abstract: Two sorts of proteins bind to, and mediate the developmental and homeostatic effects of, retinoic acid (RA): the RAR and RXR nuclear receptors, which act as ligand-dependent transcriptional regulators, and the cellular RA binding proteins (CRABPI and CRABPII). CRABPs are generally known to be implicated in the synthesis, degradation, and control of steady-state levels of RA, yet previous and recent data have indicated that they could play a role in the control of gene expression. Here we show for the first time that, both in vitro and in vivo, CRABPII is associated with RARalpha and RXRalpha in a ligand-independent manner in mammalian cells (HL-60, NB-4, and MCF-7). In the nucleus, this protein complex binds the RXR-RAR-specific response element of an RA target gene (RARE-DR5). Moreover, in the presence of retinoids that bind both the nuclear receptors and CRABPII, enhancement of transactivation by RXRalpha-RARalpha heterodimers is observed in the presence of CRABPII. Thus, CRABPII appears to be a novel transcriptional regulator involved in RA signaling.

Regulation of a Neuronal Form of Focal Adhesion Kinase by Anandamide

Abstract: Anandamide is an endogenous ligand for central cannabinoid receptors and is released after neuronal depolarization. Anandamide increased protein tyrosine phosphorylation in rat hippocampal slices and neurons in culture. The action of anandamide resulted from the inhibition of adenylyl cyclase and cyclic adenosine 3,5-monophosphate-dependent protein kinase. One of the proteins phosphorylated in response to anandamide was an isoform of pp125-focal adhesion kinase (FAK+) expressed preferentially in neurons. Focal adhesion kinaseis a tyrosine kinase involved in the interactions between the integrins and actin-based cytoskeleton. Thus, anandamide may exert neurotrophic effects and play a role in synaptic plasticity.