Effect of Systemic Administration of Mefloquine on Morphine-Induced Withdrawal Symptoms in Rats

Background and The exact mechanisms of morphine dependence and withdrawal syndrome remain unclear. Many studies have been performed to find a drug for prevention of withdrawal symptoms. The aim of this study was to evaluate the effect of mefloquine (a gap junction inhibitor) on morphine withdrawal symptoms in male rats. In an experimental study, adult male Wistar rats weighting 225± 275 g were randomly divided into 6 groups (n=8 per group). In order to induce dependency, additive doses of morphine were injected subcutaneously for 13 days. At day 13, after the last dose of morphine, saline (1 ml/kg: control) or mefloquine (5, 15, 30 mg/kg) were injected intraperitoneally. After 30 min, all groups received naloxone (4 mg/kg, ip) and the withdrawal signs including jumping, rearing, genital grooming, abdominal writhing, body grooming and wet dog shake, were recorded for 60 minutes. The results showed that mefloquine in all used doses decreased the withdrawal symptoms and the total withdrawal scores compared to control group. Mefloquine was found effective as a gap junction inhibitor in decreasing the symptoms of morphine withdrawal syndrome.