Zebrafish: A New In Vivo Model for Identifying P-Glycoprotein Efflux Modulators - Zebrafish: Methods for Assessing Drug Safety and Toxicity - page 174

(a)

Rho-HRP

Brain

Cytoplasm or
braine ndoreum

Pgp Pgp

Lumen of
brain microcaplliary

Tectum

(b)

Figure 14.2 Rho-HRP efflux from the
brain. (a) A schematic diagramof rho-HRP
efflux. During Pgp efflux (blue arrows),
rho-HRP was transported from the brain
into the cytoplasm of the brain
endothelium (black arrows) where it was
pumped into the lumen of brain
microcapillaries. After treatment with Pgp
inhibitors (red X), rho-HRP accumulates in
the brain and the cytoplasm of the brain
endothelium (red arrows). (b) Dorsal view
of brain of 7dpf zebrafish injected with
fluorescent rho-HRP (25). Region of
interest: midbrain and hindbrain region;
white box. White scale bar is 100 mm.
(c) Cartoon of zebrafish brain in dorsal
position (Wullimann and Reichert, 1996).
Injection site is marked by red arrows.
(See the color version of this figure in
Color Plates section.)

Injection site

(c)

Posterior

Anterior

was quantified using the automated measurement function. Total fluorescent signal ¼

area of ROI average fluorescence intensity in ROI. For each animal, fluorescence

intensity at (a) 15 min post-dye injection (T0) and (b) 1, 2, and 4 h post-dye injection
(T1, T2, and T4) was compared. Percent retention was then calculated for each animal
at each time point using formula (14.1):

FL ð T

n Þ

percent retention ¼

Þ

100

% :

ð 14 : 1 Þ

FL ð T0