In the present study, the effects of morphine Sensitization on morphine-induced impairment of memory formation and the state-dependent retrieval of a passive avoidance task learned under morphine influence have been investigated in mice. Pre-training administration of morphine (0.5, 2.5 and 5 mg/kg) dose dependently suppressed the learning of one-trial passive avoidance task. Pre-test administration of morphine (0.5, 2.5 and 5 mg/kg) induced state-dependent retrieval of the memory acquired under pre-training morphine influence which these effects of morphine is named state-dependent learning. The inhibitory effect of morphine (5 mg/kg) on memory formation was significantly antagonized by pretreatment administration of naloxone (0.025, 0.5 and 1 mg/kg) before the pre-training morphine. The pre-test administration of naloxone dose dependently inhibited the restoration induced by morphine (5 mg/kg). Amnesia induced by pre-training morphine significantly inhibited in morphine-sensitized mice, which had previously received once daily injections of morphine (20 and 30 mg/kg, s.c.) for 3 days. Morphine Sensitization did not affect on morphine state-dependent memory of passive avoidance. The inhibition of morphine-induced amnesia in morphine-sensitized mice suppressed by once daily injections of naloxone (0.5, 1 and 2 mg/kg) 30 min prior to s.c. injection of morphine (20 mg/kg/day for 3 days). These results suggest that morphine Sensitization affect the impairment of memory formation, but not the facilitation of retrieval induced by morphine.

Farmers are usually exposed to various inhaled allergens like pollens, mites, molds, and animal dander in their working environment which may lead to allergic rhinitis, asthma and urticaria. The purpose of this study was to identify Sensitization to various aeroallergens in farmers and their occupational allergy symptoms. This cross sectional study included 103 male farmers and 100 non-farmer healthy controls. The work-related symptoms of farmers were recorded with a questionnaire. Spirometry and skin prick tests with 15 commercial allergen extracts were performed in both farmers and controls. The rate of Sensitization to at least one of the applied aeroallergens was 47. 6% in farmers compared to 65% in the control group (OR=0. 48; CI 95%, 1. 08 to 2. 07) according to skin prick tests, after adjusting for age. Occupational allergy symptoms were reported by 54. 3% farmers. Mean FEV1/FVC was significantly lower in farmers than in controls (p<0. 001). The results of this study showed that farmers had no increased risk of Sensitization to aeroallergens. Sensitization to pollens was more prevalent than to mites among the farmers in our study and smoking was an important predisposing factor in farmers who suffered from occupational allergy symptoms.

Objective: In the present study attempts were made to further identify the effects of topiramate on the acquisition and expression of morphine-induced conditioned place preference in morphine-sensitized mice.Materials and Methods: Male Swiss-Webster mice (20-30 g) were used in this study and un-biased place conditioning paradigm was applied for this purpose. In a pilot study, the effects of morphine on place conditioning paradigm were assessed in morphine-nave animals for evaluation of ineffective doses of the drug.Results: Administration of one dose daily morphine (5 mg/kg) for 3 days followed by five days rest, in order to develop Sensitization, enhanced the conditioning induced by ineffective morphine (0.25, 0.5 and 1 mg/kg). Injections of topiramate (20, 80 and 120 mg/kg, i.p.) reduced both the acquisition and expression of morphine CPP in morphinesensitized animals. Topiramate (20, 80 and 120 mg/kg, i.p.) by itself did not induce place preference or place aversion in the mice.Conclusion: It can be concluded that to piramate administration leads to inhibition of morphine Sensitization, which may be due to glutamate and/or GABAergic mechanisms. In addition, it seems that topiramate may be useful for treatment of psychological dependence to opioids.

Repeated administration of nicotine causes incentive and behavioral Sensitization in animals. Ascorbic acid administration inhibits some effects of nicotine. In the present study, the effect of ascorbic acid administration on nicotine-induced behavioral Sensitization in Male Swiss-Webster mice (20-25 g) was investigated. Animals were injected with nicotine (0.25 mg/kg, i.p.) once daily for seven days in order to induce Sensitization. In 9th day, an ineffective dose of nicotine (0.1 mg/kg, i.p.) was administered to the mice and the activity of the animals was recorded for 20 min in an activity monitor (30 x 30 x 20 cm). Different doses of ascorbic acid (1-1000 mg/kg, i.p.) were administered to the animals in two ways: first group; the animals received ascorbic acid at days 1-7 of the experiments 10 min before the administration of nicotine (Development). Second group, the animals received ascorbic acid only at 9th day of the experiments (Expression). The results showed that: administration of nicotine (0.25 mg/kg, i.p.) for 7 days to the mice induced behavioral Sensitization in the animals. Injection of ascorbic acid (1-1000 mg/kg, i.p.) inhibits the development of nicotine-induced behavioral Sensitization in the mice. Administration of ascorbic acid (1-1000 mg/kg, i.p.) was ineffective to alter the expression of behavioral Sensitization induced by nicotine. In conclusion, administration of ascorbic acid may inhibit the development of nicotine-induced behavioral Sensitization but is ineffective to inhibit the effects of the expression of nicotine-induced behavioral Sensitization.