Mitragynine-Induced Conditioned Place Preference (CPP) And The Profiles Of Dopamine And Its Metabolites In Rats
Loading...
Date
2018-05
Authors
Mohammad Yusoff, Nurul Hasnida
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Mitragyna speciosa (M. speciosa) Korth is a traditional herbal plant indigenous to Southeast Asia. Regular use of this plant by human may lead to addiction with profound withdrawal symptoms. It is hypothesized that the abuse of M. speciosa preparations could be attributed to mitragynine, the main psychoactive compound isolated from its leaves. Therefore, comprehensive studies on the rewarding properties of mitragynine, as well as the mechanisms invoved, are needed. In the first part of the study, the rewarding properties of mitragynine (1, 5, 10 and 30 mg/kg) and its locomotor effects were investigated in Sprague-Dawley rats, using a conditioned place preference (CPP) paradigm. As a result, rats conditioned with mitragynine possesses CPP at dose of 10 and 30 mg/kg (P<0.05) as shown by the rats’ preference for mitragynine-conditoned environment, with no changes in locomotor activity at all doses tested (P>0.05). Furthermore, it is of interest to investigate whether the mitragynine-induced CPP can be maintained in the absence of mitragynine, and reinstated following mitragynine administration. From the observations, the mitragynine (10 mg/kg)-induced CPP was maintained for at least 7 days (P<0.001) after the initial CPP test, extinguished after 8 extinction trainings (P>0.05) and reinstated by priming mitragynine injection (P<0.05). In order to understand the mechanisms underlying the mitragynine-induced CPP, the involvement of opioid and gamma-aminobutyric acid B (GABAB) receptor system in the acquisition and expression phase was studied. The experiments were performed
using an opioid receptor antagonist, naloxone (0.1, 0.3 and 1.0 mg/kg) and a GABAB receptor agonist, baclofen (1.25, 2.5 and 5.0 mg/kg).
Description
Keywords
Mitragynine-induced conditioned place preference , profiles of dopamine and its metabolites in rats