Fig. 2

Pericyte-covered vessels constrict in response to phenylephrine at 4?dpf but not at 6?dpf. (A) Schematic of the experimental timeline. Imaging occurs prior to addition of 10?µM PE (0?min) and at 1 min intervals over 5?min after drug addition. (B) At 4?dpf, pericyte-covered vessels constrict in response to PE within 3?min (P=0.007, n=55 from 15 embryos). There was no constriction with vehicle (P=0.416, n=29 from 8 embryos). Vessel regions with no pericytes and diameters ?6.5??m did not respond to PE (P=0.972, n=69 from 18 embryos). When pericytes were ablated, ?6.5?µm diameter vessels constricted in response to PE (P=0.0003, n=46 from 10 embryos) but not to vehicle (P=0.289, n=128 from 22 embryos). (C-G) An example of pericyte-covered vessel constriction in response to PE within 3?min. F is an overlay of D and E. Arrows indicate constriction between the two time points. (H) At 6 dpf, pericyte-covered vessels did not respond to PE (P=0.553, n=68 from 15 embryos). Scale bars: 10?µm in C-F. Values are mean±s.d. with individual data points indicated. Significance was determined using a repeated measure one-way ANOVA (*P?0.05, **P?0.005).