Objective:

2

To evaluate the effects of

Zhumeria majdae

essential oil (ZMEO) on morphine dependence and tolerance in mice.

Methods:

2

ZMEO (10

20

and 40 mg/kg) and clonidine (0.1 mg/kg) as the positive control were injected intraperitoneally (i.p.). The effect of ZMEO and clonidine on the dependence were evaluated by counting the number of jumps induced by naloxone (5 mg/kg) while the tolerance was evaluated by the tail-flick test.

Results:

2

ZMEO at the dose of 10 mg/kg during the development period led to a significant inhibition of morphine tolerance (

P

<

0.01)

while it led to reduced morphine dependence with the doses of 20 and 40 mg/kg. ZMEO at two dose levels of 20 and 40 mg/kg indicated significant antinociceptive activity (

P

<

0.01)

and significantly reduced the withdrawal signs (number of jumps) of mice (

P

<

0.01).

Conclusions:

2

ZMEO had significant effects on morphine tolerance and dependence. The linalool rich essential oil of Z. majdae plays a major role in the reduction of tolerance and dependence induced by morphine.