Figure 3. Cortical arterioles dilate in response to CO₂/H⁺.

(A) diameter trace of a cortical arteriole with an example vessel image and fluorescence profile plots (B) show that exposure to CO₂/H⁺ caused vasodilation under baseline conditions and this response was blunted by PPADS (5 µM). Profile plot scale bars: 2000 a.u., 10 µm. (C) summary data show CO₂/H⁺-induced vasodilation of cortical arterioles under bassline conditions (N = 11 vessels) but not in PPADS (N = 6 vessels). (D–E), immunoreactivity for P2Y₂ (D) and P2Y₄ (E) receptors was detected as brightly label puncta near endothelial cells (DyLight 594 Isolectin B4 conjugate; IB4), arteriole smooth muscle (α-smooth muscle actin; αSMA), and astrocytes (glial fibrillary acidic protein; GFAP) associated with cortical arterioles (N = 3 animals). Arrows identify receptor labeling close to endothelial or smooth muscle cells and arrowheads identifies receptor labeling of astrocyte processes. Scale bar 10 µM. ##, difference in µm from baseline (paired t test, p<0.01). **, difference in CO₂/H⁺-induced % change under control conditions vs in PPADS (paired t-test, p<0.01).

DOI: http://dx.doi.org/10.7554/eLife.25232.005