Interaction between Analgesic Effect of Nano and Conventional size of Zinc Oxide and Opioidergic System Activity in Animal Model of Acute Pain

Introduction: Today Nano-medicine tries to produce new drugs to reduce the dosage and side effects of their conventional forms. According to the interaction between zinc and opioidergic system activity, this study has investigated the effect of new kind of zinc supplement, nano zinc oxide (nZnO), in compared to its conventional form (cZnO), in presence and absence of opioidergic system activity on acute pain.  Methods: Adult male Wistar rats (weighting 200±20gr) divided into groups: control (receiving saline %0.9), nZnO (1, 5, 10, 20 mg/kg), cZnO (1, 5, 10, 20 mg/kg), naloxone 1mg/kg, morphine 6 mg/kg, and co- injected groups of morphine and/or naloxone with nZnO (5mg/kg) and/or cZnO 10 mg/kg. Hot plate assay was used to evaluation of nociception and post injected latencies were recorded every 30 min for 90 min after I.P. injections of drugs. In co-injected groups latency time recorded after 60 minutes.  Results: Data indicated that both of ZnO supplements reduced latency time in dose and time dependent on the effect of nZnO was higher than cZnO. Also these components could improve anti-nociception effect of morphine and naloxone could not change the effect of these supplements.  Discussion: It seems that nZnO has more efficacy than its conventional form to showing analgesic effect that probably is related to the physicochemical properties of nZnO. Also may be these supplements have interaction with opioideric system in body

Evaluation of Anticonvulsive ٍEffect of Magnesium Oxide Nanoparticles in Comparison with Conventional MgO in Diabetic and Non-diabetic Male Mice

Introduction: Some studies show magnesium has anticonvulsive effect in some animal models. Despite of the availability of well-studied anticonvulsant drugs, this evaluation was not carried on new kind of magnesium supplement, magnesium oxide nanoparticles (nMgO). According to the interaction between magnesium and convulsion, this study was designed to evaluate the effect of nMgO on strychnine-induced convulsive model in compared to its conventional in diabetic and normal mice. Methods: Healthy male albino mice were divided to 10 groups. Diabete mellitus was induced by streptozocin in 5 groups. Conventional and nanoparticle MgO (5&10mg/kg) in presence and absence diabetes injected to mice, then strychnine injected and onset of convulsions and time of death were measured after strychnine administration. Results: Convulsive parameters did not change in normal and diabetic mice. cMgO pretreatment did not have anticonvulsant effect in strychnine-induced convulsion in normal and diabetic mice. But nMgO significantly changed convulsion onset and death time after strychnine administration in normal and diabetic status. Discussion: According to our results It seems that nMgO may be important in prevention or treatment of epilepsy and has more efficacy than its conventional form to showing anticonvulsive effect that probably is related to the physicochemical properties of nMgO, specially in diabetic subjects, a point that need to further investigation

The Modulating Effect of Glucocorticoids and Opioid System on Anxiety Related Behavior in Young and Adult Rats: Economic Evaluation of Infliximab in UC Patients

One of the main components of the stress system is hypothalamus- pituitary-adrenal (HPA) axis. Acute activation of μ-opioid receptors increases the activity of the HPA axis, leading to release of ACTH and corticosterone. Glucocorticoids can change behaviors, depend on age but there were no evidences about the interaction between age, opioid system and glucocorticoids. In this experiment, effects of dexamethasone (1mg/kg) and RU486 (20mg/kg) as an agonist and antagonist of glucocorticoid receptors, morphine (5mg/kg) and naloxone (20mg/kg) as an agonist and antagonist of the opioid system on anxiety in young and adult male Wistar rats were examined. The percentage of time in the open arms of plus maze was evaluated for anxiety behavior also percentage of the number of entries in closed arms was evaluated for locomotor activity. The results showed that morphine (5mg/kg) and dexamethasone (1mg/kg) had an anxiolytic effect on both young and adult rats while just in young rats reduced locomotor activity. RU486 could prevent the anxiolytic effect of morphine, and the anxiolytic effect of dexamethasone had been inhibited by naloxone in young but it wasn't seen in adult rats. These results show an interactive effect between glucocorticoids and the opioid system on mediating anxiety that can be influenced by age

Effect of matricaria recutita on acute pain in the presence and absence of sex hormones

<p><strong>BACKGROUND</strong>: Chamomile is a beneficial herbal drug that is used as an anti-inflammatory, sedative and anti-allergic agent. The mechanism of action of matricaria recutita (MR), a specious of chamomile, in nociception in male and female animals is not fully understood. In this study, the sedative effect of a species of chamomile, MR, on acute pain was investigated in both male and female adult mice in the presence and absence of sex hormones.<br /><strong>METHODS</strong>: Male and female NMRI mice weighing 28 ± 3 grams were used. Animals of each sex were divided into intact and gonadectomized groups. Intact group received saline or MR extract (10, 30, 50 mg/kg, intraperitoneally). Gonadectomized group contained two subgroups: a) group that received saline or MR hydro alcoholic extract (50 mg/kg, I.P.), and b) group that received sex hormones (testosterone in male mice and estradiol benzoate and progesterone in female mice), both with and without MR extract (50mg/kg, IP). The analgesia times in all groups were evaluated by hot plate test.<br /><strong>RESULTS</strong>: MR increased analgesia time both in intact and gonadectomized male and female mice, but had no effect in the presence of pharmacological doses of testosterone (2 mg/kg, subcutaneous) in male mice, and estradiol benzoate (0.1 mg/kg, SC) and progesterone (0.5 mg/kg, SC) in female mice.<br /><strong>CONCLUSIONS</strong>: It seems that MR can induce a pain-relieving effect with and without physiological doses of sex hormones in male and female mice, but sex hormones probably interact with its analgesic effect in their pharmacological doses.<br /><strong>KEY WORDS</strong>: Matricaria recutita, pain, testosterone, estradiol benzoate, progesterone, hot plate.</p&gt

Nanoparticles of Magnesium Oxide Improve Autistic-Like Behaviors Induced by the Maternal Separation Model Without Affecting Gonads Structure: Nanoparticles of Magnesium Oxide Improve Autistic-Like Behaviors

Maternal separation in the early days after birth can induce autistic-like behaviors in animals. Nanoparticles of Magnesium oxide (nano-MgO) can decrease anxiety, pain perception and improve animal memory. Also, sex hormones are involved in the formation of many behaviors. In this study, the effects of nano-MgO on behavioral responses in immature rats and gonadal histological structures of adult rats in the autistic-like model of maternal separation were investigated. Juvenile male and female offspring (60±5g) were divided into control and maternal-separated groups. The maternal separation was done by separation of the pup from the mother for 1 hour/daily/1-10 postnatal days. Nano-MgO 2.5 and 5 mg/kg were injected intraperitoneally during the 31±2-35±2 postnatal days.  Pain perception and memory were evaluated after the first, third, and last injections and on 45±2 postnatal days. Social interaction, anxiety level, and motor activity were evaluated on 36±2 postnatal days. Tissue samples were removed from the testis and ovary for histological studies on 73±2 postnatal days. Maternal separation increased pain perception, anxiety, and motor activity, and also decreased social interaction index, and impaired memory in animals. Nano-MgO improved anxiety, and social interaction, induced analgesia, and modulated hyperactivity. Also, memory impairment was reversed by the nano-MgO2.5 mg/kg while it was not significant. There were no alterations in the histological and histometrical structure of the testis and ovary of adult rats between the studied groups. The behavioral complications caused by the autistic-like model can be corrected by nano-MgO; however, the gonads were not affected by the autism condition and nano-MgO application

Anxiogenic Effects of Acute Injection of Sesame oil May be Mediated by β-1 Adrenoceptors in the Basolateral Amygdala;-1 Adrenoceptors in the Basolateral Amygdala

Purpose: A few studies have indicates that the sesame oil influences anxiety, but many reports show that β-1 adrenoceptors (ARs) of the basolateral amygdala (BLA) plays a pivotal role in this regard. Therefore, in this study the effect of acute injection of sesame oil on anxiety-like behavior in the presence and absence of the BLA β-1 ARs in the male Wistar rats were investigated. Methods: Guide cannulas, for seven groups of rats, were implanted bilaterally into the BLA. Two weeks after the stereotaxic surgery, anxiety-like behaviors (the OAT%, OAE % and locomotor activity) were evaluated by Elevated Plus-Maze (EPM) for all groups. 3 groups received different volumes of sesame oil (i.p.) and they were compared with control group (received saline via i.p.), and the anxiogenic volume of sesame oil (1.5ml/kg) was determined. Then, 3 other groups received constant effective volume of sesame oil (1.5ml/kg) along with 3 different doses of betaxolol, selective β-1 ARs antagonist, intra BLA microinjection in order to be compared with sesame oil group (1.5 ml/kg). Results: The acute injection of sesame oil with the volume dependent manner showed an anxiogenic effect with reduction of the OAT% and OAE% which the maximum effect of sesame oil was observed in the dose of 1.5mg/kg. Also, betaxolol with dose dependent manner attenuated the anxiogenic effects of sesame oil (1.5mg/kg), but this reduction could not remove the anxiety effects completely. Conclusion: It seems that the sesame oil acute (i.p.) injection induces anxiety, and this effect is attenuated by inhibition of β-1ARs in the BLA