Although the brain has been considered an insulin-insensitive organ, recent reports on the location of insulin and its receptors in the brain have introduced new ways of considering this hormone responsible for several functions. The origin of insulin in the brain has been explained from peripheral or central sources, or both. Regardless of whether insulin is of peripheral origin or produced in the brain, this hormone may act through its own receptors present in the brain. The molecular events through which insulin functions in the brain are the same as those operating in the periphery. However, certain insulin actions are different in the central nervous system, such as hormone-induced glucose uptake due to a low insulin-sensitive GLUT-4 activity, and because of the predominant presence of GLUT-1 and GLUT-3. In addition, insulin in the brain contributes to the control of nutrient homeostasis, reproduction, cognition, and memory, as well as to neurotrophic, neuromodulatory, and neuroprotective effects. Alterations of these functional activities may contribute to the manifestation of several clinical entities, such as central insulin resistance, type 2 diabetes mellitus (T2DM), and Alzheimer’s disease (AD). A close association between T2DM and AD has been reported, to the extent that AD is twice more frequent in diabetic patients, and some authors have proposed the name “type 3 diabetes” for this association. There are links between AD and T2DM through mitochondrial alterations and oxidative stress, altered energy and glucose metabolism, cholesterol modifications, dysfunctional protein O-GlcNAcylation, formation of amyloid plaques, altered Aβ metabolism, and tau hyperphosphorylation. Advances in the knowledge of preclinical AD and T2DM may be a major stimulus for the development of treatment for preventing the pathogenic events of these disorders, mainly those focused on reducing brain insulin resistance, which is seems to be a common ground for both pathological entities.

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DIETZENBACHER E. and VELÁ ZQUEZ E. (2007) Analysing Andalusian virtual water trade in an input -output framework, Regional Studies 41, 1-12. Andalusian agricultural sectors are relatively small, but account for 90% of annual water consumption. More than 50% of the agricultural final demands is exported to other Spanish regions or abroad. Using the concept of virtual water within an input -output framework, it is found that a substantial part of Andalusian water consumption is embodied in its exports. Considering the virtual water content of its trade, Andalusia is a net exporter of water. Examining regional policy aspects, a reduction in the exports abroad of agricultural products yields considerable benefits in terms of water savings, while the negative effects are only moderate.Input -output models Virtual water Trade and sustainability DIETZENBACHER E. et VELÁ ZQUEZ E. (2007) Une analyse des échanges andalous d'eau virtuelle dans le contexte d'un tableau d'échanges interindustriels, Regional Studies 41, 1 -12. Les secteurs agricoles andalous sont relativement petits mais expliquent 90% de la consommation d'eau. Plus de 50% de la demande finale agricole est exporté aux autres régions espagnoles ou à l'étranger. En employant la notion d'eau virtuelle dans le contexte d'un tableau d'échanges interindustriels, il s'avère qu'une part importante de la consommation andalouse d'eau s'explique par les exportations. Compte tenu de l'importance de l'eau virtuelle pour ses exportations, l'Andalousie s'avère une exportatrice nette d'eau. Sur le plan régional, une réduction des exportations à l'étranger des produits agricoles rapporte des retombées positives non-négligeables en termes des économies d'eau, tandis que les retombées négatives ne sont que limitées.Modèles des échanges interindustriels Eau virtuelle Echanges et pérennité DIETZENBACHER E. und VELÁ ZQUEZ E. (2007) Analyse des virtuellen Wasserhandels in Andalusien in einem Input -OutputRahmen, Regional Studies 41, 1-12. Die landwirtschaftlichen Sektoren Andalusiens sind relativ klein, machen aber 90% des jähr-lichen Wasserverbrauchs aus. Mehr als 50% des landwirtschaftlichen Endbedarfs wird in andere spanische Regionen oder ins Ausland exportiert. Mit Hilfe des Konzepts von virtuellem Wasser innerhalb eines Input -Output-Rahmens kamen wir zum Ergebnis, dass ein erheblicher Teil des Wasserverbrauchs von Andalusien in den Exporten der Region verkörpert ist. Am virtuellen Wassergehalt seines Handels gemessen ist Andalusien ein Netto-Exporteur von Wasser. Bei einer Untersuchung der regionalpolitischen Aspekte zeigt sich, dass sich eine Verringerung des Auslandsexports von landwirtschaftlichen Erzeugnissen deutlich positiv auf die Wassereinsparungen auswirkt, während die negativen Effekte nur mäßig ausfallen.Input -Output-Modelle Virtuelles Wasser Handel und Nachhaltigkeit DIETZENBACHER E. y VELÁ ZQUEZ E. (2007) Análisis del agua virtual de Andalucía según una estructura de entrada-salida, Regional Studies 41, 1-12. Los sectores agrícolas en Andalucía son relativamen...

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Glucagon-like peptide-2 (GLP-2) is a potent intestinotrophic/satiety hormone that acts through a G proteincoupled receptor. To determine whether or not GLP-2 has any effect on cellular proliferation on neural cells, we examined the effects of this peptide on cultured astrocytes from rat cerebral cortex. The expression of the GLP-2 receptor gene in both cerebral cortex and astrocytes was determined by RT-PCR and Southern blotting. Also, cells responded to GLP-2, producing cAMP in a dose-dependent manner (EC 50 ¼ 0.86 nM). GLP-2 also stimulated the DNA synthesis rate in rat astrocytes. When proliferation was assessed by measuring [ 3 H]thymidine incorporation into DNA or staining cells with crystal violet, GLP-2 produced a dose-dependent increase in both parameters. Similarly, when the numbers of cells in different phases of the cell cycle were measured by flow cytometry, a dose-dependent decrease in those in the G0-G1 phase and an increase in those in the S and G2-M phases were observed after 24 h incubation with GLP-2. By contrast, the number of hypodiploid cells was not affected during the experimental time. Also, GLP-2 produced a significant increase in the mRNAs of c-fos and c-jun when gene expression was determined by Northern blotting. These results suggest that GLP-2 directly stimulates the proliferation of rat astrocytes; this may open new insights in the physiological role of this novel neuropeptide.

In the field of Ecological Economics, the need of using physical indicators to analyse economic processes, at the same time they serve as tools in decision making, has been lately highlighted. Virtual Water (VW) and Water Footprint (WF) are two useful indicators in achieving this objective, the first one from the perspective of production, the second one from that of consumption. This difference between them is interesting inasmuch as it allows to identify the subjects who are responsible for water consumption, whether producers or consumers, and proves both indicators' potential when designing water management policies. In this work, we consider a hypothesis according to which there is a clear difference between the two concepts-Virtual Water and Water Footprint-and this difference, although evident in their respective conceptualizations, is not reflected in their estimations and applications. This is true to the point that the two concepts are often used as synonyms, thus wasting the enormous potential associated to their difference. Starting from this hypothesis, our objective is, first of all, to highlight this evident but ignored difference between VW and WF through a deep and thorough literature review of the conceptual definitions and contributions, the methodologies developed and the applications made regarding the two concepts. Second, we intend to make a conceptual and methodological proposition aimed at underlining the differences already mentioned and to identify responsibilities in water consumption. We do it by

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