Zebrafish: A Predictive Model for Assessing Seizure Liability - Zebrafish: Methods for Assessing Drug Safety and Toxicity - page 165

For the seizure assay, we analyzed high-speed movement (greater than 20mm/s,
Fig. 13.1, red lines) (Winter et al., 2008). Distance traveled was measured in 1min
intervals ( D ) for 60 min for each zebrafish. An Excel spreadsheet containing
analyzed data was generated at the end of each experiment. Incorrect tracking data
(e.g., detection of microwell wall instead of animals) were eliminated from the final
data set prior to analysis. D ( N 20 or 30) was plotted against recording time

(Fig. 13.2). From this data, we identified peak D for each concentration. We then
compared peak D for compound-treated animals and D for carrier control zebrafish at
the same time point. Compound effects were normalized to percent increase in peak
D using formula (13.1):

¼

D compound
D control

percent increase in peak

D ¼

1 100

% :

ð 13 : 1 Þ

Student's t -test was then used to determine if compound effects were significant

( P < 0.05).

13.3 RESULTS

Using quantitative video-based movement tracking systems, zebrafish have been
shown to be a predictive animal model for assessing compound-induced seizure-
like locomotion (Baraban et al., 2005; Berghmans et al., 2007; Winter et al.,
2008). For these studies, similar to previously reported methods (Winter et al.,
2008), we used the VideoTrack System (ViewPoint Life Sciences) to measure
distance traveled in 1min intervals ( D ) for 60min for nine seizure inducing com-
pounds, including PTZ, 4-AP, picrotoxin, strychnine hemisulfate, methoxychlor,
amoxapine, aminophylline hydrate, bicuculline methiodide, and enoxacin; lidocaine
was used as a negative control compound (Table 13.1). The systemmeasured D at three
speeds: low (less than 4mm/s), medium (between 4 and 20mm/s), and high (greater
than 20mm/s). To assess seizure-like movement, we focused on D at high speed. We
identified peak D during the 60min recording period and the concentration used. Then,
we compared peak D for compound-treated animals and D for carrier controls at the
same time point. Student's t -test was used to determine if compound effects were
significant ( P

< 0.05).

13.3.1 High-Speed Distance Traveled in 1min
Intervals

Using varying compound concentrations (Table 13.1), D was recorded for 60 min and
mean D was calculated and plotted against time for each concentration ( N ¼ 20 or 30).

Carrier control was included in each experiment. Figure 13.2 shows the kinetics of
high-speed movement for compound-treated and carrier control animals for three
compound concentrations.