Role of the Lateral Paragigantocellular Nucleus in the Network of Paradoxical (REM) Sleep: An Electrophysiological and Anatomical Study in the Rat

The lateral paragigantocellular nucleus (LPGi) is located in the ventrolateral medulla and is known as a sympathoexcitatory area involved in the control of blood pressure. In recent experiments, we showed that the LPGi contains a large number of neurons activated during PS hypersomnia following a selective deprivation. Among these neurons, more than two-thirds are GABAergic and more than one fourth send efferent fibers to the wake-active locus coeruleus nucleus. To get more insight into the role of the LPGi in PS regulation, we combined an electrophysiological and anatomical approach in the rat, using extracellular recordings in the head-restrained model and injections of tracers followed by the immunohistochemical detection of Fos in control, PS-deprived and PS-recovery animals. With the head-restrained preparation, we showed that the LPGi contains neurons specifically active during PS (PS-On neurons), neurons inactive during PS (PS-Off neurons) and neurons indifferent to the sleep-waking cycle. After injection of CTb in the facial nucleus, the neurons of which are hyperpolarized during PS, the largest population of Fos/CTb neurons visualized in the medulla in the PS-recovery condition was observed in the LPGi. After injection of CTb in the LPGi itself and PS-recovery, the nucleus containing the highest number of Fos/CTb neurons, moreover bilaterally, was the sublaterodorsal nucleus (SLD). The SLD is known as the pontine executive PS area and triggers PS through glutamatergic neurons. We propose that, during PS, the LPGi is strongly excited by the SLD and hyperpolarizes the motoneurons of the facial nucleus in addition to local and locus coeruleus PS-Off neurons, and by this means contributes to PS genesis

Effet d'un supplément duodénal de protéines sur l'ingestion des vaches laitières avec ou sans traite incomplète

International audienc

The Synthesis and Electrochemistry of Peptide Functionalized Conducting Materials

Abstract not Available.</jats:p

Recognition Properties of Chiral Electrodes

Abstract not Available.</jats:p

La nutrition azotée influence l'ingestion chez la vache laitière

National audienceAn increase in protein content of dairy cow diets is often associated with an increased feed intake, however the magnitude of these answers and the mechanisms involved are still not well understood. This review characterizes the effects of nitrogen and protein content of the diet on feed intake in dairy cows and discusses the various hypotheses concerning their mechanisms. The supply of degradable nitrogen to the microbial population and the availability of protein for milk synthesis affects dry matter intake. These effects can be quantitatively important and generally increase with time. If the role of degradable nitrogen on microbial activity explains largely the feed intake increase, the action of proteins on the regulation of intake is less easily explained and could be multi-factorial. Similar to monogastric animals, possible modifications of the amino acid balance could also modify the control of feeding behaviour and explain the short-term intake effects. However, the increase in time of the feed intake responses to proteins militates more for indirect action via, for example the energy demand or the mobilization of the reserves, than for direct protein action on feed intake control. The response law to protein content and a better understanding of the mechanisms involved could be helpful in incorporating the effects of protein nutrition into the models of feed intake prediction.L’augmentation des teneurs en protéines des régimes est souvent associée à une augmentation de l’ingestion chez les vaches laitières, mais l’amplitude de ces réponses et les mécanismes sont encore mal connus. Cet article caractérise les effets des teneurs en azote et en protéines des régimes sur l’ingestion des aliments par les vaches laitières et discute les différentes hypothèses concernant les mécanismes. La fourniture en azote dégradable aux microbes du rumen et la disponibilité en protéines pour la synthèse du lait sont capables de stimuler l’ingestion. Ces effets peuvent être quantitativement importants et le plus souvent augmentent au cours du temps. Si le rôle de l’azote dégradable sur l’activité microbienne dans le rumen permet de bien comprendre l’augmentation des quantités ingérées, l’action des protéines sur la régulation de l’ingestion est moins facile à expliquer et pourrait être multifactorielle. Comme chez les monogastriques, les modifications possibles d’équilibre des acides aminés pourraient également modifier le contrôle de la prise alimentaire et expliquer des effets à court terme sur l’ingestion. Cependant, l’augmentation de l’effet des protéines sur l’ingestion au cours du temps milite plus pour une action indirecte, via la demande d’énergie ou la mobilisation des réserves par exemple, que pour une action directe des protéines sur le contrôle de la prise alimentaire. Ces hypothèses pourraient permettre d’intégrer les effets de l’alimentation protéique dans les modèles de prévision des quantités ingérées

Characterization of phenomena occurring at the interface of chiral conducting surfaces

Chiral conducting surfaces based on leucine functionalized terthiophenes can detect bioorganic molecules via formation of hydrogen bonds.</p