Western blot analysis in brain capillaries (A) and immunofluorescence in hippocampus and cortex (B) of INSR, and IRS1 content in brain capillaries (C). Change in concentrations of insulin signaling-related protein (D) in TBS-soluble fractions of the parietotemporal cortex of insulin injected mice compared to saline injected mice. Data are presented compared to the average of saline-injected mice. For immunofluorescence, blue = DAPI, green = blood vessels (lectin) and red = INSR. Data are presented as mean ± SEM. Data were compared with an unpaired Student t-test. *p < 0.05. INSR = insulin receptor, IRS1 = insulin receptor substrate 1, Akt = protein kinase B, PKB. GSK3β = glycogen synthase kinase-3β. ERK = extracellular signal-regulated kinases. PDK1 = Pyruvate Dehydrogenase Kinase 1. JNK = c-Jun N-terminal kinases. PI3K = Phosphoinositide 3-kinase. PTEN = Phosphatase and tensin homolog. mTOR = mammalian target of rapamycin.