[Effect of beta-estradiol on traumatic memory after posttraumatic stress disorder induced by modified singleprolonged stress model in male Rats]

Post-traumatic stress disorder [PTSD] is an anxiety, which is induced by exposure to life-threatening trauma and produces memory dysfunctions. This study was done to evaluate the effect of beta-estradiol on traumatic memory after post-traumatic stress disorder induced by modified single-prolonged stress model in male rats. This experimental study was done on 70 male Wistar rats, weighted 200-250 grams. Initially 30 rats randomly allocated into control, shock and single prolonged stress accompanied shock [SPS and S]. In SPS and S group immobilized for 2h, followed immediately with a 20 min forced swim conducted in a cylindrical filled with water. After recuperating for 15 min, animals anesthetized with ether. After 30 min recovery, stressed rats placed in the conditioned fear system [CFS]. They received one 1mA, 4 second electric foot shock and remained in the chamber for another 60 second before being returned to their home cages. Shock group: Animals placed in CFS and only received the same shock as previous experiment. Naive group: Animals were removed from their home cages and exposed to chamber without receiving any foot shock. 1, 2 and 3 week later, animals in all groups were re-exposed to the shock chamber for 3 min, in order to examine conditioned fear response. In the second experiment rats were injected with beta-estradiol [90 micro g/kg], one and two week after training. Date were analyzed using SPSS-16, ANOVA and LSD tests. SPS and S significantly induced freezing response [traumatic memory] compared with controls and shock groups [P<0.05] following three weeks. This response significantly reduced due to repetitive injection of beta-estradiol in rats [P<0.05]. After three weeks causes of enhanced freezing response [traumatic memory] compare with both, shock and sham groups [P<0.001]. beta-estradiol significantly reduced this response in rats [P<0.001]. beta-estradiol's administration following PTSD induction by modified single-prolonged stress, significantly decreased the freezing response. Therefore, beta-estradiol can prevent the formation of traumatic memory

Pentoxifylline decreases allodynia and hyperalgesia in a rat model of neuropathic pain

Pentoxifylline [PTX] is a non-specific cytokine inhibitor that has been reported to attenuate pain in several animal models and humans. However, long-term therapeutic effects of PTX on neuropathic pain in a rat model of chronic constriction injury [CCI] are not completely clear. This study was conducted to examine the effect of long-term administration of PTX on neuropathic pain in rats. Neuropathic pain was induced by sciatic nerve ligation using of CCI model in rats. Rats were randomly assigned into sham, CCI-saline treated, and CCI-PTX treated [30 or 60 mg/kg ip] groups. PTX or saline administered at 30 min before CCI and daily for 14 days post-CCI. At the days of 3, 7, 11 and 14 following CCI, by using standard methods effects of thermal hyperalgesia, thermal and mechanical allodynia in all groups were examined using the standard methods. The CCI-saline treated group showed a significant increase in mechanical and thermal allodynia, and thermal hyperalgesia as compared with the sham group in the tested days. Administration of the higher dose of PTX [60 mg/kg/day], but not the lower dose [30 mg/kg/day] significantly reduced mechanical and thermal allodynia, as compared with the CCI-saline treated group on days of 3, 7, 11 and 14 [all P values<0.001]. Also, both doses of PTX significantly reduced thermal hyperalgesia as compared with the CCI-saline treated group on these days [all P values<0.001]. Results of this study show that chronic administration of PTX reduces the neuropathic pain in a rat model of CCI. Thus, this drug may have a therapeutic application in the treatment and management of neuropathic pain in humans

Prevalence of hypertension among the adult population of Semnan province

A population based cross-sectional survey was conducted to determine prevalence of hypertension in the adult population of Semnan province. The study was conducted from September 2005 until February 2006, using a multistage cluster sampling method to select a representative sample. A total of 3799 adults, aged 30-70 years, were examined. Two blood pressure measurements were obtained by trained observers using a standard sphygmomanometer after a 5 minute seated rest. Information on history of hypertension and use of antihypertensive medication was obtained using a standard questionnaire. Body mass index [BMI] and waist to hip circumference were determined. Fasting blood sample was drawn for measurement of glucose, total cholesterol and triglycerides. Prevalence's of hypertension in men and women were 24.1% and 24.7% respectively. In both sexes, prevalence of hypertension increased with age. No significant difference was found in prevalence of hypertension in rural [24.1%] and urban [24.8%] regions. Among hypertensive subjects, 40.6% were aware of their hypertension [men: 30% women: 49.7%, P < 0.001], only 25.5% were taking antihypertensive medication [men: 19.5% women: 30.6% P < 0.001] and 41.2% had their blood pressure controlled [men: 41% women: 42.3%]. In 93.7% of men and 97.2% of women with hypertension, at least one other cardiovascular risk factor was present and its prevalence was increased in both genders with age. Finally, gender [OR: 1.28 in men], diabetes [OR:1.86], obesity [OR:1.7], high triglycerides [OR:1.3], high cholesterol [OR: 1.3], and abdominal obesity [OR: 1.79] were positively associated with hypertension [P < 0.001]. Hypertension was present in one-fourth of the population. Majority of hypertensive subjects in this region still remain undetected and control of hypertension is also inadequate. This calls for urgent prevention and control measures for hypertension in Semnan province

Does whole body exposure to GSM-950 MHz electromagnetic fields affect acquisition and consolidation of spatial information in rats?

This study was planned to examine the effects of whole-body exposure to GSM-950 MHz electromagnetic fields [EMFs] on acquisition and consolidation of spatial memory in rats using a water maze task. In experiment 1, the animals were given two blocks of five trials per day for three consecutive days in a water maze task. The interval between blocks was 4h. Before each training session, the animals were exposed to 950 MHz EMFs for 45 min with lower-[0.835 mW/cm[2]] or higher-power [1.166 mW/cm[2]] densities. In experiment 2, the animals were given two blocks of 5 trials with a 3 min interval between blocks. Immediately after the last trial, they were exposed to EMFs for 45 min with lower-or higher-power densities. In both experiments, 48 h after the last training day a 60 s probe test was done. Results from experiment1 [pre-training exposure to EMFs] indicated no significant differences in performances of exposed and non-exposed groups either during acquisition [learning] or during probe test [memory retention]. Results from experiment 2 [post training exposure to EMFs] also indicated no significant differences among groups during acquisition or probe test. In these experiments, no effect of exposure to 950 MHz on acquisition or consolidation of spatial navigation of rats in a water maze was detected

[ role of intrahippocampal microinjections of anisomycin on dexamethasone-induced modulation of memory consolidation in rats]

Evidence indicates that hippocampus and activation of glucocorticoid receptors in this area are necessary for emotional learning and memory processes; also some studies suggest that glucocorticoid's effects probably involve with processes of protein synthysis in the hippocmapus. The aim of this study was to determine the role of intrahippocampal microinjections of anisomycin [[AIMS] as a protein synthysis inhibitor]] on dexamethasone-induced modulation of memory consolidation in the passive avoidance learning [PAL] task in rats. In this study, 90 male Wistar rats [250-300 gr] were surgically implanted bilaterally with cannulae aimed at the dorsal hippocampus [DH] were trained in PAL task. In experiment 1. Dexamethasone [0.1, 0.5, 1 and 3 mg/kg IP] was injected immediately after training and vehicle injected into DH. In experiment 2. Anisomycin [0.5,1 micro g/ micro l/side] or vehicle were injected bilaterally into the DH followed immediately by IP injection of Dexamethasone [1 mg/kg] or vehicle. Two days after training, retention tests were done and step-through latency [STL] and total time spent in light chamber [TLC] of apparatus were recorded during 10 min and compared with controls. Data indicated that injection of Dexamethasone immediatly after training enhanced memory consolidation [P<0.01] and this effect was blocked by injection of ANS in to the DH [P<0.01]. The findings above showed that glucocorticoids play on important role in consolidation of emotional learning and probably in processes of protein synthesis in the hippocampus may play an important role in mediating these effects

Low-power density of 950 MHz rediation does not affect long-term potentiation in rat dentate gyrus

Over the last decade, exposure to non-ionizing electromagnetic waves due to base station antenna has increased. This in vivo study was planned for evaluating the effects of whole-body exposure to 950 MHz field of GSM mobile phone system on rat dentate gyrus long-term potentiation. 24 naive male Wistar rats [3 month old, 225 +/- 25 g] were randomly divided in the three groups [sham-exposed, GSM and continuous field exposed]. The exposure program was planned for 10 sessions at 3 days. Animals were exposed to electromagnetic field for 45 minutes in a circular plastic chamber [mean power density=0.835 mW/cm[2]]. Immediately after end exposure, anesthesia was induced for long term potentiation [LTP] induction. Field potentials were recorded and analyzed using the population spike amplitude and EPSP slope for 60- min. There were no significant differences in population spike amplitude, EPSP slope and EPSP slope maintenance among the three groups. This study provides no evidence indicating that long-term potentiation can be affected by the whole-body exposure to low-power density of 950 MHz field of GSM mobile phone system

[ effect of GSM mobile phone base station waves on hippocampus synaptic plasticity]

Over the last decade, exposure to electromagnetic waves due to base station antenna has increased. This in vivo study was planned for evaluating the effects of 950 MHz waves of GSM mobile phone system on dentate gyrus long-term potentiation. 32 naive male Wistar rats [3 months old, 220 +/- 15 g] were randomly divided into four groups [sham-exposed, continuous 950 MHz, 950 MHz with modulation and 950 MHz GSM field exposed]. The exposure program was planned for 10 sessions at 3 days. Animals were exposed to electromagnetic field for 45min in a circular plastic chamber [mean electric field = 50.4 V/m]. Immediately after ending exposure, anesthesia was induced for LTP induction. Field potentials were recorded and analyzed using the population spike amplitude, EPSP slope, EPSP slope maintenance and EPSP duration for 60-min. There were no significant differences in population spike amplitude, EPSP slope and EPSP slope maintenance and EPSP duration among the four groups. This experiment provides no evidence indicating that rat's long-term potentiation can be affected by the whole-body exposure to 950 MHz field of GSM mobile phone system

[ effect of dexamethasone on anxiety related behavior in mice]

Previous studies have suggested that activation of the glucocorticoid receptors may have a modulatory effect on fear and anxiety. Therefore, the aim of this study was to determine the role of glucocorticoid hormones on modulation of anxiety in elevated plus-maze model in mice. In this experimental study, 60 male mice [25-30 g] were included. They were randomely divided into test and control groups. The test group received different doses of dexamethasone, as an agonist of glucocorticoid receptors, at 0.1, 0.3, 1, 2 and 10 mg/kg, Subcutaneausly, and the control group received the same volume of 2% ethanol in normal saline 30 minutes before the evaluation of their behavior. Twenty five minutes after the injection, the mice were put in a black box for 5 minutes to induce their activity and stress. The animals were then individually transferred to a standard elevated pluse-maze in regulated time and the percentage of time spent in the open arms and the ratio of open arm entries to total entries in 5 mins was measured. Results indicated that dexamethasone with the doses 0.3 and 1mg/kg, significantly reduced anxiety in mice [p<0.01]. However, this effect was not observed at 0.1 and 2mg/kg. Our findings also showed that denamechasone at the dose of 10 mg/kg increased anxiety behavior in mice [p<0.01]. The findings of this study indicated that glucocorticoids have important role in modulation of anxiety related behavior in a dose dependent manner using an elevated plus maze model in mice

[Effects of corticosterone injections after training and memory reactivation on recall of fear memory in rats]

Recent evidence indicated that when a stabilized memory is recalled or reactivated, it again becomes labile and initiates a time-dependent process referred to "reconsolidation". Considering the documented role of stress hormones on emotional memory, the purpose of this study was to compare the effects of glucocorticoids on consolidation and reconsolidation of a fear conditioning memory. Adult male Wistar rats were trained in fear conditioning system. In experiment 1, rats were placed into context and after 180 s were given two 2 s, 0.4 mA shocks with an interval of 120 s. Twenty seconds after the final shock, rats removed from the context box and were injected with different doses of corticosterone or vehicle. In reconsolidation experiments, rats received 2 s, 0.4 mA shocks with an interval of 120 s [moderate memory] or given eight 2 s, 1.5 mA shocks with an interval of 62 s [strong memory]. Thirty seconds after the final shock, rats removed from the context box. For reactivation, 24 h later rats were returned to the chamber for 90s. Immediately after reactivation, rats were injected with different doses of corticosterone or vehicle. Twenty-four hours after training or memory reactivation, rats were returned to the context box for 5 min. Seconds of freezing [defined as the absence of all visible movement oxcept respiration] during the retrieval testing were scored for each rat. The findings indicated that injections of corticosterone after training enhanced memory consolidation at dose of 3 mg/kg. Injections of the drug after memory reactivation did not change recall of moderate memory, but impaired recall of strong memory at dose of 3 mg/kg. The data indicate that glucocorticoids have opposite effects on consolidation and reconsolidation of contextual fear conditioning memory. Further studies are needed to determine the underlying mechanisms

[ effects of cimetidine on motor activity: an evaluation the role of opioid receptors]

Effects of cimetidine [CIM] on locomotor is controversial. This study was designed to evaluate the effects of CIM on motor activity and possible roles of opioid receptors in CIM-induced decrement in locomotor activity in mice. Thirty-six male mice [25-30gr] were divided into six groups in this study. Locomotor activity was evaluated using an automated activity monitor system. CIM [50 mg/kg, i.p.] was injected 25 min before testing in presence or absence naloxone [2 mg/kg, sc]. Morphine [5 mg/kg, i.p] was injected 25 min before testing in the presence or absence CIM. Decreased motor activity significantly. Pretreatment of or morphine did not change CIM - induced response significantly. The results showed that CIM significantly decreased motor activity in mice [P=0.000]. Pretreatment of nalxone did not change CIM-induced response significantly. Morphine alone did not change motor activity. Pretreatment of CIM did not change morphine-induced response. Data indicated that cimetidine can reduce motor activity independence from interaction with opioid receptors

[Systemic administrations of Bombesin modulate acute pain in mice]

Bombesin [BBS] is a tetra-decapeptide, which is widely distributed in mammalian central nervous system. Due to presence of BBS in neural pathways that involved in control of pain, the aim of this study was to test the effects of this peptide on acute pain in mice. Male albino mice [25-30 gr.] were used in this study. Hot plate [HP] and Tail Flick [TF] models were applied for the evaluation of BBS effects on acute pain. Five minute prior to measuring pain, different doses of BBS [1.25, 2.5, 5, 10 and 20 micro g/kg] or saline were respectively injected to test and control animals by the route of intraperitoneal. The results of current study indicated that peripheral injection of BBS produces significant analgesic effects in both TF and HP models. The present data provide evidences that BBS plays an important role in control of acute pain. Further studies are required to determine the underlying mechanisms

[Verapamil enhances the impairing effects of stress on retrieval of long-term memory in rats]

This study investigated an interaction between acute restraint stress and verapamil, as a blocker of L-type voltage sensitive channels on retrieval of long-term memory. Young adult male rats were trained in one trial inhibitory avoidance task [1mA, 1.5s footshock]. On retention test given 48 hr after training, the latency to re-enter dark compartment and time spent in light chamber of the apparatus were recorded. Thirty min before retention test, the rats were exposed to a 10 min of restraint stress in a Plexiglass with or without prior treatment of verapamil [5, 10, 20 mg/kg]. The results showed verapamil pretreatment enhanced the impairing effect of stress on memory retrieval. The applied stress increased circulating corticosterone levels as assessed immediately after the retention test, indicating that stress-induced impairment of memory retrieval is mediated, in part, by increased plasma levels of glucocorticoids. Verapamil did not affect on this response. These findings indicate that acute restraint stress impair retrieval of long-term memory, and provide evidence for the existence of an interaction between stress and L-type voltage calcium channels on this process

[Assessment of hydroalcoholic extract of thymus vulgaris on neurogenic and inflammatory pain in mice]

The side effects of anti-nociception chemical drugs caused notice to medical plants. This study was performed to investigate the effects of hydroalcoholic extract of Thymus vulgaris [TV] on neurogenic and inflammatory pain in formalin test in mice. 40 male albino mice [20-30 gr] were used. TV [100, 500 mg/kg] as extract and saline were injected 30 mine before formalin test. Indexes for evaluation were duration of licking and foot elevation for assessment of acute pain [5 min] and chronic pain [15-40 min] after injection of formalin 5% [25 microl] in paw. Results indicated that TV has analgesic effect in both doses [P<0.01], and higher dose [500 mg] was more effective. Findings showed that hydroalcoholic extract of TV can modulate acute and chronic pain. Further research is required to determine the mechanisms by which TV has an inhibitory effect on pain sensation

Effects of aqueous extract of seed of Coriandrum sativum on acute pain in mice

Since use of synthetic drugs for relief of pain has many side effects, today medical plants are becoming more prominent as substitute therapeutic agents. Previous findings indicate that Coriandrum sativum [CS] modulates pain in both animal and human. The present work investigated the effects of CS seed on acute pain using hot plate and tail flick models. Albino mice [25-30 g] were used for this study. Aqueous extract of CS seed was injected in doses of 100 and 200 mg/kg 30 min before test. The analgesic effect of the drug on acute pain was evaluated using Hot plate and Tail flick models. Results indicated that CS has analgesic effect in both doses in both models and higher dose of the drug was more effective [p<0.01]. The findings above showed that CS could modulate acute pain. Further research is required to determine the mechanisms by which CS has an inhibitory effect on pain sensation

Assessment the effects of hydroalcoholic extract of Thymus vulgaris acute pain in hot plate and tail flick in mice

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 Hydroalcoholic extract of Thymus vulgaris [TV] on acute pain in Hot plate and Tail flick models. 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 indicated that TV has analgesic effect in both doses in both models [P<0.01], and higher dose of the drug was more effective. 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

comparison between the therapeutic effects of the ultrasound and low-level laser treatment on the healing process of the carpal tunnel syndrome

This study was designed to compare the efficacy of ultrasound and laser treatment for mild to moderate idiopathic carpal tunnel syndrome [CTS]. Ninety hands in 50 consecutive patients with CTS confirmed by electromyography participated randomly in two experimental groups, ultrasound therapy and low level laser therapy [LLLT]. Intervention in each group included 15 daily treatment sessions [5 sessions/week]. Ultrasound treatment [1 MHz, 1.0 W/cm[2], pulse 1:4, 15 min/session] applied to the area over the carpal tunnel of one wrist and LLLT [9 joules, 830 NM infrared laser at five points] applied to other wrist. Measurements were performed before and after treatment and also after 4 weeks follow up and included pain assessment by visual analogue scale; electroneugraphic measurement [motor and sensory latency, motor and sensory action potential amplitude], pinch and grip strength. Improvement was significantly more pronounced in ultrasound group than in LLLT group for variables; motor latency and motor action potential amplitude [P<0.0001]; sensory latency [P<0.001]; sensory action potential amplitude [P<0.05], hand grip strength [P<0.01], finger pinch strength [P<0.0001] and pain relief [P<0.0001], with sustained effects after follow up period. Results indicate both ultrasound and laser were effective, but ultrasound was better than laser. Since some effective results were seen due to the laser therapy, further investigation is needed to investigate the effects of combination of these treatments in patients with mild to moderate CTS