Antinociceptive Orofacial Activity of Kalanchoe Brasiliensis Aqueous Extract through Modulation of the TRPV1 Receptor on Zebrafish Model

Kalanchoe brasiliensis Cambess is a native Brazilian plant that is traditionally used to threat skin, pain, inflammation and gastrointestinal disorders.Here, we evaluated the in vivo orofacial nociception and possible mechanisms of action of the aqueous extract from the leaves of Kalanchoe brasiliensis (ELKB) using adult zebrafish models.The agonist cinnamaldehyde, menthol, capsaicin, acid saline, glutamate, and hypertonic saline were used to evaluate the nociception response of zebrafish, using the open field test to quantify the locomotion activity.In another set of experiments, animals were pre-treated with capsazepine to investigate the mechanism of antinociception.ELKB did not alter the fish's locomotor system and significantly reduced the orofacial nociceptive behavior induced by capsaicin, acid saline, and glutamate compared with the naive group.Capsazepine effectively inhibited the antinociceptive effect of ELKB.This study showed that ELKB has the potential antinociceptive activity by inhibiting the activation of TRPV1, ASICs, and NMDA receptor in adult zebrafish (D. rerio) without affecting locomotion in the animals.