كليدواژه :
Morphine , Sensitization , نيكوتين , مورفين , Cross-Sensitization , nicotine , حساسيت , mice , Conditioned Place Preference
چكيده لاتين :
Objective; It seems that nicotine and morphine have similar effects in the nervous system. The present study examined whether interaction occured between the effects of nicotine and morphine by observing if cross-sensitization exists between nicotine and morphine on induction of conditioned place preference (CPP) in female mice.
Material and Methods: Female Swiss-Webster mice (W: 20-25gr) were used throughtout and CPP was induced in animals by the Kim method. Sensitization was induced by single injection of morphine or nicotine for three consecutive days followed by five days resting. On the sixth day of the experiments, sensitization was assesed in animals by injection of very low doses of morphine or nicotine.
Results: Subcutaneous (s.c.) injections of morphine (1-1(1 mg/kg) can produce a significant place preference. Furthermore interapretoneal (i.p.) administration of nicotine (0.5-2 mg/kg) also induced a significant CPP. Administration of opioid (5 mg/kg, s.c., once daily for three consecutive days and then five day resting) induced sensitization in animals. Injection of ineffective doses of morphine (0.25, 0.5 and 1 mg/kg, s.c.) induced CPP in animals. Injection of ineffective doses of nicotine (0.1, 0.25 and 0.5 mg/kg, i.p.) to the morphine sensitized animals also induced a significant CPP. Injection of nicotine (OA mg/kg, i.p.; once daily) for 3 consecutive days followed by five days resting, induced sensitization in animals. Injection of ineffective closes of morphine (0.25, 0.5 and 1 mg/kg, s.c.) induced significant CPP in these animals. Ineffective doses of nicotine (0.1, 0.25 and 0.5 mg/kg, i.p.) induced a significant CPP in the nicotine sensitized animals.
Conclusion: it apears that opioidergic and nicotinic receptor mechanism(s) may he involved in induction of CPP by morphine and nicotine in morphine or/ nicotine sensitized animals.
