Chemical composition of Zhumeria majdae essential oil and its effects on the expression of morphine withdrawal syndrome and tolerance to the anticonvulsant effect of morphine on pentylenetetrazole-induced seizures in mice

Abstract

Abstract Regarding the proven anticonvulsant effect of Zhumeria majdae essential oil (ZMEO) in previous studies we were prompted to investigate the ZMEO effects on the tolerance to the anticonvulsant effects of morphine and the morphine withdrawal syndrome. Tolerance to the morphine anticonvulsant effect was induced in mice by subcutaneous injection of 2.5 mg/kg of morphine for 4 days. Subsequent doses of ZMEO (20 mg/kg) were used to study the expression and development of morphine tolerance. Clonidine was used as the standard drug to inhibit the morphine withdrawal syndrome symptoms. To study the ZMEO effect on withdrawal syndrome, mice received appropriate morphine values for 4 days and on the fifth day, 60 min before administration of naloxone. The effective dose of ZMEO was determined and the number of jumps, stands and changes in the dry stool weight, as symptoms of withdrawal syndrome were evaluated. The dose of 20 mg/kg of ZMEO decreased the tolerance in development and expression groups significantly. Counting the number of jumping, standing and defecation were assessed 30 min after morphine and 1 h after the vehicle and clonidine. The dose of 40 mg/kg ZMEO decreased all the signs of withdrawal syndrome significantly. ZMEO was analyzed by GC/MS and linalool (53.1%) and camphor (23.8%) were characterized as the main components. The results suggest that ZMEO possesses constituent(s) that have activity against tolerance to the anticonvulsant effects of morphine and the morphine withdrawal symptoms.