2.5. Evaluation of antinociceptive activity in mice
2.5.1. Acetic acid-induced abdominal writhes in mice
The peripheral analgesic activity of Bxb was evaluated in CD1
female mice using the acetic acid-induced writhing test (Garcı´a
et al., 2002). In this test, groups of female mice (n¼6) were
injected intraperitoneally (i.p.) or orally (p.o.) with 0.1 mL of 0.6%
(v/v solution) acetic acid 1 h before the treatment with saline
solution, aspirin, dexamethasone and/or Bxb (1 mg/animal). Five
minutes after the administration of acetic acid, mice were placed
in separated boxes and the number of abdominal writhes was
counted for 20 min, and the experimental was repeated twice.
2.5.2. Formalin test
The formalin test was conducted according to the method of
Hunskaar and Hole (1987). CD1 female mice weighing 20–25 g
were divided into different groups with six animals each. Control
group received 0.1 mL saline solution, Aspirin (45 mg/kg¼1 mg/
animal), and Dexamethasone (45 mg/kg¼1 mg/animal) were
used as a reference group. Bxb extract were administered p.o. or
i.p. at the dose of 1 mg/animal. An intraplantar injection of 1%
formalin solution (20 mL) was given into the right hind paw of the
animal groups with (n¼6). After the different treatments the
animals were placed in separated boxes and pain-like behaviours
(licking/biting and flinching) were recorded in two phases: firstphase
(neurogenic phase) (0–5 min), and the second-phase
(inflammatory phase) (20–30 min) after formalin injection.