Figure 1.

Experimental design. The acetic acid abdominal writhing protocol evaluated the pretreatment with Spirulina (3–300 mg/kg, p.o.), indomethacin (10 mg/kg), or vehicle (0.9% NaCl 10 mL/kg), and after 60 min, 0.6% acetic acid was administered via i.p. to assess the nociceptive behavior. In the formalin test, its application occurred viai.pl. after 60 min of treatment and the time spent in different behavioral states was evaluated. The harmful behavior induced by the menthol, cinnamaldehyde, and capsaicin protocol was administered i.pl. after 60 min of treatment and aimed to assess the involvement of TRPM8, TRPA1, and TRPV1, respectively. The glutamatergic system’s involvement was analyzed with the administration of glutamate (20 µmol/paw) via i.pl. and the time spent in different behavioral states was evaluated for 15 min. To assess the involvement of the opioid system, a pretreatment with naloxone (1 mg/kg, i.p.) was administrated 20 min before treatment with Spirulina (30 mg/kg, p.o.), and after 60 min, nociceptive behaviors were evaluated.