Background& Objective: Black pepper is frequently used in Iranian traditional medicine. as an analgesic (e.g. for toothache). This investigation was conducted to evaluate the response of mice to pain induced by HOT-PLATE and formalin test either with or without piperine (one of the active substances of the pepper).Materials& Methods: This randomized experimental study was performed on mice. HOT-PLATE and formalin tests were planned to pain measurement. The mice were divided into two groups in each arm of study (HOT-PLATE and formalin test groups). The data of control (saline) and drug (piperine) groups were separately compared in each arm of study with student T -test and ANOV A. The difference between each point of data was considered significant at p-value under 0.05.]Results: There was not a- significant difference in tolerance time of subjects between HOT-PLATE and saline groups. Piperine (25, 50 and 75 mg/kg) along with morphine (10 mg/kg) causes significant increase to saline group in tolerance time and also significant increase to morphine group, but in formalin test piperine could have significant effect in decreasing the pain induced by of formalin on mice. These effects are comparable with morphine. In formalin test," pain has two phases. The first phase is acute and the second one is chronic that begins from 15-20 minutes. Acute pain has central effect and chronic pain has peripheral pathway and piperine causes decreasing response to formalin test at the first phase of pain. Naloxone can prevent these effects in all groups. In formalin test and HOT-PLATE, the effect of piperine were dose dependent.Conclusion: Piperine can centrally act on the nociception pathway and its effect on opioid system exhibits as an enhancement opioid effect. The effects are dose dependent and will be inhibited by opioid antagonist.

There is much evidence indicating that the serotonergic system involves in the central regulation of nociceptive sensitivity. Several drugs are able to produce analgesic effect through serotonin re uptake inhibition or effect on it's receptors. Studies show that antidepressants such as desipramine, amitriptyline, clomipramine, citalopram and zimelidine have analgesic effect in experimental pain models; however, there isn't any report concerning analgesic effect of chronic and acute administered fluoxetine. The aim of this study was to investigate the effect of chronic and acute injected fluoxetine on HOT PLATE test. Results of this study showed that chronic (0.16, 0.2 and 0.24 mg/kg, i.p. for 5 days) and acute (0.2 and 0.24 mg/kg, i.p.) administration of fluoxetine, as a serotonin re uptake inhibitor, produced significant analgesia. Fluoxetine (0.24 mg/kg, i.p.) increased analgesic effect of morphine (1 mg/kg, i.p.) significantly. Furthermore, analgesic effect of fluoxetine (0.24 mg/kg, i.p. and 0.24 mg/kg, i.p., for 5 days) was reversed by naloxone (2 mg/kg, i.p.). Results obtained from this study showe that chronic and acute injection of fluoxetine induce analgesic effect on HOT PLATE test through activation of opioidergic neurons. The exact mechanism of interaction between serotonergic and opioidergic system is not clear and remains to be elucidated.

Background: Recently, many researchers have been involved in finding means to prevent or delay deterioration by oxidative reactions in cosmetic preparations. More recently, research has focused on developing safer and more effective antioxidants from natural sources. Objective: In this research the antioxidant activity of Green tea extract in comparison with commercial antioxidants in 2% hydroquinone cream were evaluated. Method: Green tea extract was tested for antioxidative activity in comparison with antioxidants (sodium metabisulfite and butilated hydroxy toluene BHT) at 0.1%, 0.5%, 1.0% and 2.0% w/w in 2% w/w hydroquinone cream. The systems were incubated in a dark room at 25°± 0.5°C and 45°± 0.5°C for three months. The physical stability and the percentages of hydroquinone remaining after two weeks and one, two, and three months were determined. Results: The experiment revealed that oxidation degradation of hydroquinone was accelerated by heat even with existence of antioxidants. In the third month at 25°± 0.5°C and 45°± 0.5°C, the extract demonstrated more antioxidant activity from other two commercial antioxidants at all concentrations, with about 43-53% and 32-44%, respectively, more hydroquinone remaining than in the control system (P<0.001). In the third month, the preparation containing 0.1%, 0.5%, 1.0% and 2.0% extract gave good physical formulation stability with about 70%, 75%, 77% and 81% hydroquinone remaining at 25°± 0.5°C, and 50%, 54%, 58% and 62% hydroquinone remaining at 45°±0.5°C, respectively. Conclusion: This suggested the possibility of using a Green tea extract as an effective natural antioxidant for substances that are oxidation-susceptible.

Introduction: Since uses of antinoceception chemical drugs for relief of pain have many side effects; today medical plants are very noticeable. The present work investigated the effects of Hydoalcoholic extract of Thymus vulgaris )TV( on acute pain in HOT PLATE and Tail flick models. Material and Methods: Albino mice (20-30 gr) were used for this study. Hydroalcoholic extract of TV seed was injected in doses of 100 and 500 mg/kg 30 min before test. Then the analgesic effect of the drug on acute pain was evaluated using HOT PLATE and Tail flick models.Results: Results indicated that TV has analgesic effect in both doses in both models (P<0.01), and higher dose of the drug was more effective.Conclusion: These findings showed that TV could modulate acute pain. Further research is required to determine the mechanisms by which TV has an inhibitory effect on pain sensation.

In this paper, the wear of work roll in HOT PLATE rolling is introduced and the parameters affecting wear mechanisms in HOT strip mill are investigated. In addition, different wear mechanisms in HOT rolling and the differences between these mechanisms in different stands are explained. Using the finite element method and the rolling equations, a work roll wear model is proposed. Wear is modeled using the resultant pressure distribution along the roll barrel. To obtain the tentative coefficient, summation of wear in each pass schedule is obtained and calibrated via actual wear of samples tested in the Mobarakeh Steel Company. Finally, the theoretical wear values are compared with those of the experiment. The predicted wear profiles are found to be in good agreement with those of the experimental measured values.

Background: Sesame oil is applied in physiological research as a solvent. It contains unsaturated fatty acids such as linoleic acid, sesamol and lecithin. In his research effect of dietary sesame oil on pain perception was studied.Objective:Methods: N-MRI male rats (360±20 g) were used. Animals divided to two groups: 1) control group and 2) experimental group (three subgroups that ate dietary plats that contain 10% sesame oil for 28, 42 and 56 days respectively and a subgroup ate dietary plats that contain 1% lecithin). After 28, 42 and 56 days pain was evaluateded by digital HOT PLATE and formalin test. Data was analyzed by one way ANOVA or T- test.Results: HOT PLATE test: Sesame oil diet decreased pain in the 28, 42, 56 days significantly.Formalin test: Sesame oil diet decreased pain only in 42 days (p<0.02) significantly in early phase. Sesame oil diet decreased pain in the 28 days (p<0.0001) and 42 days (p<0.03) and 56 days (p<0.001) significantly in late phase of formalin test and also we found significant difference between control and lecithin group (p<0.006) in late phase.HOT PLATE test: Dietary plats (10% sesame oil) decreased acute pain perception in all experimental groups (p<0.03).Conclusion: Our data indicated that dietary sesame oil could increase pain threshold. It seems that sesame oil lecithin (as a source for acetylcholine) or unsaturated fatty acid (altered plasma membrane properties or PGs metabolism) involve in this pain threshold alternation.

Background and Purpose: Cuminum Cyminm (CC) is one of the plants whose aqueous extract is used in traditional medicine as anti-convulsive anti-epileptic and as a treatment for some visceral pains. However no substantial reports can be found of its effects on the peripheral pain in lab animals. Therefore this study was condcated to determine the effects of the IP injection of the aqueous extract of CC on the acute peripheral pain in HOT PLATE (HP) and Tail Flick (TF) tests in mice.Methods and Materials: This experimental study was conducted on 56 male Albino mice (8 groups each with 7 mice) weighing 25-30 gr. 200 and 500 mg/kg of the aqueous extract of CC or saline of the volume were injected intraperitoeally 30 minutes prior to the tests. Pain measrment criteria in the TF test was the response time to the pain by raising the tail and in the HP test the time to begin to lick the front legs or raising the rear feet.Results: The IP injection of the CC aqueous extract with the doses of 200 and 500 mg/kg significantly increased the response time to the pain in HP and TF tests (P<0.01) in comparison with the control groups and the group receiving saline. The effect was however more remarkable with the 500 mg/kg dose.Conclusion: The results of this study indicated that the aqueous extract of CC reduced the acute peripheral pain in the mice.