Are the acute caffeine effects on insulin sensitivity mediated by adenosine receptors?

Type 2 diabetes is a chronic disease associated with a modern lifestyle. Caffeine is a non-selective adenosine antagonist, that when applied acutely or chronically have distinct effects on insulin sensitivity. The main objective of this work was to investigate if A(1) adenosine receptors mediate the acute effect of caffeine intake on insulin sensitivity. The effect of the acute administration of caffeine and the A(1) selective antagonist, DPCPX, was tested in Wistar rats. Insulin sensitivity, basal glycemia and the skeletal muscle expression of Glut4 transporters as well as AMPK alpha 1 were evaluated. Acute caffeine administration decreased insulin sensitivity in a dose-dependent manner an effect that could be mediated by a decrease in Glut4 expression in skeletal muscle. The acute administration of 50 nM of DPCPX decreased significantly insulin sensitivity. In conclusion, the effect of acute caffeine administration on insulin sensitivity is mediated by A(1) receptors and involves a decrease in Glut4 expression in skeletal muscle.