Fig. 4

Rhodamine 123 distribution is altered in the presence of verapamil.

A) Dye distribution and quantification experiments using rhodamine 123 (R123) were performed as described for Figure 1. Graph shows mean fluorescent intensity (± std dev.) for each treatment. Rhodamine 123 (grey bars), a substrate for mammalian ABCB1, ABCB4 and ABCB5, was excluded from the brain by 8 d.p.f. which, coincides with the onset of zebrafish Abcb/4/5 staining in the vasculature of the CNS. When 8 d.p.f. and 10 d.p.f. larvae were incubated with verapamil (white bars), an inhibitor of ABCB1, ABCB4 and ABCB5 in mammals, R123 failed to be excluded, consistent with blocked Abcb1/4/5 function. B and C) Representative images of parasagittal section of 5 d.p.f. larvae following pericardial injection of saline (B) or Rhodamine 123 (C). Fluorescence in the brain is observed following injection of Rhodamine 123. Scale bar represents 50 μm.