Rotarod apparatus for rats

The rotarod test^{26 (link)}
was used to evaluate the effect of the plant extract of J.
nigra leaf on motor coordination in rats. The test was
performed to validate the results obtained during the examination of
antinociceptive activity. Rats were placed on a horizontal rod that rotates
about its long axis (rotarod apparatus for rats, 47 700, Ugo Basile, Milano,
Italy) at a constant speed of 15 r/min. The rats must walk forward to avoid
falling. The time at which the rats fell off the rotating cylinder was
recorded. The cut-off time was 180 s. Two days before the experiments, the
animals were trained to balance on the rotating rod. On the day of the
experiment, animals that could remain on the rod for 180 s in 2 separate
measurements were selected. In the test groups, rats were administered i.p.
the extract. The control rats received an i.p. injection of the same volume
of vehicle. The post-treatment latency to remain on the rotating rod was
measured at 6 time points, which corresponded to the time points when the
nociception was assessed.

Motor coordination and learning were tested using the rotarod apparatus for rats (Ugo Basile, Italy) with 4 rods. Two NR animals had to be excluded from testing due to an animal handling error, specifically an accidental flooding of their waiting cage, the night before the first training day. On the first day NR (13) and AF (n = 12) rats were gently placed on each rod set at a steady, slow speed of 4 rpm, and trained to remain on the rod for 60 sec. After this habituation trial, each animal was submitted to 4 trials per day for 5 consecutive days, with an intertrial interval of 15 min. The trial started when all rats moved in the right direction. The rotarod was set at increasing speeds ranging from 5 to 40 rpm over 5 min, and rats were left on the rod for an additional 3 min. The rats' latency to fall off the rod within this period was recorded. The daily mean latency was used for statistical analysis.