Fig. 2

Effect of LPS on LAT1 mRNA expression in brain vessels of rats and mice. A X-ray film images of radioactive LAT1 in situ hybridization in rat forebrain sections. Note the reduced “graininess” of the labeling 9 h after LPS, which is especially visible in the thalamus. Neuronal labeling, well visible in the hippocampus and the hypothalamus, including the dorsomedial nucleus (DMH), is not altered. At 48 h after LPS, the “grainy” signal, which represents blood vessels, is more intense than in control brains over the entire section. Cp choroid plexus, DMH dorsomedial hypothalamic nucleus, Hip hippocampus, MHb medial habenular nucleus. Scale bar 2 mm. B Darkfield emulsion autoradiography images demonstrate the time course of LAT1 mRNA (silver grain accumulation, white) in the rat cortex. In the control cortex, intense hybridization signal is associated with major longitudinal vessels (arrows) and a multitude of small capillaries (numerous bright spots). This labeling vanishes by 4 and 9 h after LPS, only the much lower level parenchymal labeling (primarily neuronal) remains. At 48 h after LPS, hybridization signal labels a larger part of the vasculature than in controls, including major vessels (arrows) and capillaries. Scale bar 100 µm. C LAT1 mRNA in vessels of the mouse cortex. In the control brain, silver grains form clusters over major vessels (arrow) and capillaries, which disappear 9 h after LPS. 48 h after LPS, LAT1 hybridization signal in vessels is more intense than in controls. Arrows indicate major vessels. Scale bar 100 µm