The loss of P2X7 receptor expression leads to increase intestinal glucose transit and hepatic steatosis

In intestinal epithelial cells (IEC), it was reported that the activation of the P2X7 receptor leads to the internalization of the glucose transporter GLUT2, which is accompanied by a reduction of IEC capacity to transport glucose. In this study, we used P2rx7−/− mice to decipher P2X7 functions in intestinal glucose transport and to evaluate the impacts on metabolism. Immunohistochemistry analyses revealed the presence of GLUT2 at the apical domain of P2rx7−/− jejunum enterocytes. Positron emission tomography and biodistribution studies demonstrated that glucose was more efciently delivered to the circulation of knockout animals. These fndings correlated with increase blood glucose, insulin, triglycerides and cholesterol levels. In fact, P2rx7−/− mice had increased serum triglyceride and cholesterol levels and displayed glucose intolerance and resistance to insulin. Finally, P2rx7−/− mice developed a hepatic steatosis characterized by a reduction of Acaca, Acacb, Fasn and Acox1 mRNA expression, as well as for ACC and FAS protein expression. Our study suggests that P2X7 could play a central role in metabolic diseases

Climatology of nighttime medium-scale traveling ionospheric disturbances (MSTIDs) in the Central Pacific and South American sectors

We present occurrence rate statistics for nighttime medium-scale traveling ionospheric disturbances (MSTIDs) in the Central Pacific and South American sectors using data collected by 630.0 nm filtered CCD imaging systems. The data were collected from September 2006 through December 2012. In general, the statistics are in good agreement with the basic linear theory of MSTIDs, with observations coinciding with low F10.7A values, representative of solar minimum. Overall, MSTIDs are observed in approximately 68% of the usable nights near the solstices at mid-latitudes and approximately 20% of the usable nights for equinox periods. Observations closer to the geomagnetic equator yielded a maximum occurrence rate of about 10–20% during the solstices and about 0–3% during the equinoxes. The lower number of MSTID observations near the low latitudes is attributed to limitations of MSTID growth rate, propagation, and/or geometrical observational effects. The relatively large number of MSTID occurrences during the solstices can be accounted for by the neutral wind contribution to the MSTID growth rate either at the local or magnetic conjugate point