Attenuation of visceral nociception by [alpha]-bisabolol in mice: investigation of mechanisms

Background We previously described the visceral antinociceptive property of [alpha]-bisabolol (BISA) in mouse models of visceral nociception induced by cyclophosphamide and mustard oil (MO). This study examined the effect of BISA in mouse models of visceral nociception induced by acetic acid, capsaicin, formalin, and the contribution of the nitric oxide system, [alpha]^sub 2^, K^sub ATP^ ^sup +^, 5-HT^sub 3^ and TRPV1 receptors to the effect of BISA on MO-evoked nociceptive behaviors. Mice were pretreated orally with BISA (50, 100 and 200 mg/kg) or vehicle, and the pain-related behavioral responses to intraperitoneal administration of acetic acid or intracolonic injection of MO were analyzed. Results BISA significantly suppressed the nociceptive behaviors in a dose-unrelated manner. The antinociceptive effect of BISA (50 mg/kg) was show to be glibenclamide resistant, but it was not blocked by pretreatment with the other antagonists tested. In the open-field test that detects sedative or motor abnormality, mice received 50 mg/kg BISA did not show any per se influence in ambulation frequency. Conclusions However, their precise antinociceptive mechanisms of action have not been determined.