Copaifera langsdorffii Desf. tree oleoresin-induced antinociception recruits µ < sub > 1 < /sub > - and κ -opioid receptors in the ventrolateral columns of the periaqueductal grey matter

Behav Brain Res. 2023 Dec 22:114832. doi: 10.1016/j.bbr.2023.114832. Online ahead of print.ABSTRACTPopular medicine has been using oleoresin from several species of copaiba tree for the treatment of various diseases and its clinical administration potentially causes antinociception. Electrical stimulation of ventrolateral (vlPAG) and dorsolateral (dlPAG) columns of the periaqueductal gray matter also causes antinociception. The aim this study was to verify the antinociceptive effect of oleoresin extracted from Copaifera langsdorffii tree and to test the hypothesis that oleoresin-induced antinociception is mediated by µ1- and κ-opioid receptors in the vlPAG and dlPAG. Nociceptive thresholds were determined by the tail-flick test in Wistar rats. The copaiba tree oleoresin was administered at different doses (50, 100 and 200mg/kg) through the gavage technique. After the specification of the most effective dose of copaiba tree oleoresin (200mg/kg), rats were pretreated with either the µ1-opioid receptor selective antagonist naloxonazine (at 0.05, 0.5 and 5µg/ 0.2µl in vlPAG, and 5µg/ 0.2µl in dlPAG) or the κ-opioid receptor selective antagonist nor-binaltorphimine (at 1, 3 and 9 nmol/ 0.2µl in vlPAG, and 9 nmol/ 0.2µl in dlPAG). The blockade of µ1 and κ opioid receptors of vlPAG decreased the antinociception produced by copaiba tree oleoresin. However, the blockade of these receptors in dlPAG did not alter copaiba tree oleoresin-induced antinociception. These data sug...

Source: Behavioural Brain Research - December 24, 2023 Category: Neurology Authors: Vanessa Cristina Santana Bruna Magda Marmentini Ge órgia Guedes Cruz Leila Camila de Jesus Luana Walicheski F ábio Henrique Beffa Talles Henrique Pichinelli Maffei Rafaela Vieira Streg Valdir Flor êncio Veiga-Júnior Carla Regina Andrighetti Milena Cam Source Type: research