In support for a central role of the drop in vascular wall tension in the initiation of vascular ERK1/2 activation, we have recently shown that in a model of distal MCA occlusion contractile ETB receptors were upregulated only downstream from the occlusion, whereas the immediate upstream MCA, experiencing the same low degree of ischemia in the surrounding tissue but no drop in vascular wall tension, did not show changes in ETB receptor function. This evidence concerns the gene MAPK3 and ischemia.