Estudo do mecanismo de ação da atividade antinociceptiva da Riparina II de Aniba riparia em camundongos

Abstract

The unripe fruit of the species of Aniba riparia (Nees) Mez, found some alkamides, one in particular, Riparin II (RipII) has an interesting therapeutic potential. Previous studies showed that it had anxiolytic and antidepressant effects as well as an antiinflammatory effect. This study was conducted after approval by the CEUA/UFC (n° 41/15). The aim of the study was to evaluate the role of RipII in nociception process, possible mediators involved and the possible pharmacological mechanisms involved. They used male Swiss mice and was initially performed the toxicity test according to OECD 425, the oral toxicity test for 28 days and the molecular modeling of the TRPV1, TRPA1 and bradikynin receptors. The models of nociception were performed: writhes induced by acetic acid, hyperalgesia mechanical induced nociceptive agents (carrageenan, PGE2 and epinephrine), nociception test induced by intraplantar injection of capsaicin, cinnamaldehyde, menthol, bradykinin, PMA and 8-Br-cAMP, and investigate the role of potassium channels and some neurotransmitter systems. Molecular modeling has shown that RipII has a Strong interaction with TRPV1, TRPA1 and bradykinin receptors. The RipII (25 and 50 mg/kg, p.o.) was able to significantly reduce nociception induced by acetic acid and hyperalgesia induced by carrageenan, PGE2 and epinephrine. In the test of writhing induced by acetic acid was carried out time curve at a dose of 50 mg/kg and we observed that the effects of RipII-50mg/kg appeared within 30 minutes and persisted for 240 minutes. In the investigation of the analgesic mechanism, RipII showed effect related to the K+ ATP channels, TRPV1, TRPM8, ASIC, bradykinin receptors, PKA and PKC. To study possible neurotransmission pathways was performed writhing model of acetic acid-induced and the animals were pretreated different substances. The analgesic effect of RipII (50 mg/kg, p.o.) was reversed when the animals were pretreated with naloxone, glibenclamide and yohimbine, while the animals showed no behavioral change when pretreated with NAN-190, ritanserin, ondansetron, atropine or haloperidol. These data demonstrate that RipII produces a significant antinociceptive effect via molecular mechanisms of K+ ATP channels, TRPV1, TRPA1, TRPM8, ASIC, PKC, PKA, bradykinin receptors, α2 adrenergic receptors and opioid receptors.