32 24765236 Iranian Society of Physiology and Pharmacology 824 Others Reconstruction of the neural network model of motor control for virtual C.elegans on the basis of actual organism information Nasem Ashora Zahra Hassanpour-ezatti Majid c Raesi Behrooz Dolati Ardeshir c Shahed University 1 4 2012 16 1 1 10 10 03 2012 06 05 2012 Introduction: C. elegans neural network is a good sample for neural networks studies, because its structural details are completely determined. In this study, the virtual neural network of this worm that was proposed by Suzuki et al. for control of movement was reconstructed by adding newly discovered synapses for each of these network neurons. These synapses are newly discovered in the actual organism by laser ablation technique. Methods: An input weight of each neuron in this network was obtained from wormweb site. Internal state of each neuron and the whole network in this new situation were calculated after mathematical modeling. Then output of the network in this new model was simulated and drawn by Simulink software in MATLAB environment and compared with Suzuki model outputs. Results: The results show that in spite of adding new synapses to the last model, its output shape does not change and preserve its sinusoidal form, and only its frequency, phase and amplitude of internal state of whole network are changed after modification. Also, adding of these new synapses to models change silent neurons in forward motion in Suzuki model to sinusoidal internal state producing neurons in this new situation. Conclusion: These findings not only show that this neural network has high capability for production of more output patterns than previously supposed, but also illustrates the effect of addition of new synapses per each neuron and rewiring on the whole network outputs as a simulation of situation that possibly happens after neural plasticity.
802 Others Alterations of the electroencephalogram sub-bands amplitude during focal seizures in the pilocarpine model of epilepsy Motaghi Sahel Niknazar Mohammad Sayyah Mohammad Babapour Vahab Vosoughi Vahdat Bijan Shamsollahi Mohammad Bagher 1 4 2012 16 1 11 20 13 12 2011 15 01 2012 Introduction: Temporal lobe epilepsy (TLE) is the most common and drug resistant epilepsy in adults. Due to behavioral, morphologic and electrographic similarities, pilocarpine model of epilepsy best resembles TLE. This study was aimed at determination of the changes in electroencephalogram (EEG) sub-bands amplitude during focal seizures in the pilocarpine model of epilepsy. Analysis of these changes might help detection of a pre-seizure state before an oncoming seizure. Methods: Rats were treated by scopolamine (1mg/kg, s.c) to prevent cholinergic effects. After 30 min, pilocarpine (380 mg/kg, i.p) was administered to induce status epilepticus (SE) and 2 hours after SE, diazepam (20 mg/kg, i.p) was injected to suppress the seizures. EEG was recorded in the epileptic rats by superficial electrodes. EEG signal in each rat was decomposed to its sub-bands alpha, beta, gamma, theta and delta by Daubechies wavelet transform. The power (square of amplitude) of sub-band during focal seizures was compared with the same sub-band in pre-ictal stage and the percent of changes in each rat was calculated. Results: SE occurred in 65% of the animals and happened 39.4±5.4 min after injection of pilocarpine. Focal and generalized seizures were developed 3.8±0.4 and 7.0±0.5 days after SE, respectively. Although power of EEG and its sub-bands decreased during focal seizures, the changes were not statistically significant. The greatest decrease in power pertained to beta and gamma sub-bands, while alpha and theta sub-bands underwent the least changes. Conclusion: Based on the protocol used in this study, it seems that the power of EEG sub-bands does not change during focal seizures in pilocarpine model of epilepsy. 792 Others Frequency-dependent electrophysiological properties of concealed slow pathway of isolated rabbit atrioventricular node preparation after fast pathway ablation in a functional model khori vahid l Naeimipour samaneh m alizadeh Ali-Mohammad n pourabouk mona o Badaghabadi fakhri p Rajaei maryah Shariatnezhad sepideh Moheimani hamidreza saleki saeed Zeyghami mohammadali Nayebpour mohsen l Golestan Cardiovascular Research Center, Gorgan, Iran m Department of Biology, Faculty of Basic Science, Azad University Science & Research Center, Tehran n Cancer Research Center, Tehran University of Medical Sciences, Tehran, Iran o Golestan Cardiovascular Research Center p Golestan Cardiovascular Research Center Golestan Cardiovascular Research Center Golestan Cardiovascular Research Center Golestan Cardiovascular Research Center Golestan Cardiovascular Research Center Golestan Cardiovascular Research Center Department of Pharmacology, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran 1 4 2012 16 1 21 32 28 11 2011 16 01 2012 Introduction: Intranodal pathways of atrioventricular (AV) node play a vital role in the delay of conduction time in response to various atrial inputs. The present study was aimed to determine the frequency-dependent electrophysiological properties of concealed slow pathway according to a functional model of isolated rabbit atrioventricular node preparation after fast pathway ablation. Methods: Experiments were carried out in rabbit isolated heart AV-nodal preparations (N=8) by superfused/perfused mode. Extracellular recording was carried out from transitional cells of posterior and anterior extension of AV-node and upper part of atrium and its bundle. Unipolar silver electrode (100 μm) and direct voltage (100-110 V) was applied to create AV-nodal fast pathway ablation. Results: Minimum conduction time (AHmin) was significantly increased after fast pathway ablation (p<0.05). Fast pathway ablation had no significant impact on fatigue phenomenon but significantly reduced facilitation value (p<0.05). Rate-dependency properties of concealed slow pathway were explained according to functional nodal model. Conclusion: The mathematical functional model accurately simulated frequency-dependent electrophysiological properties of concealed slow pathway after fast pathway ablation, but some modifications are necessary for accurate prediction of nodal behavior in various cycle lengths and in arrhythmia. Concealed slow pathway may be considered as a potential electrophysiological substrate of fatigue and facilitation phenomenon 801 Others Electrophysiological study of amygdale-induced changes in the excitability of CA1 hippocampal pyramidal neurons in male adult rats Ghotbeddin Zohre Mirnajafi-Zadeh Javad Semnanian Saeed Janahmadi Mahyar Neuroscience Research Center and Department of Physiology, Medical School, Shahid Beheshti University of Medical Sciences. 1 4 2012 16 1 33 43 12 12 2011 15 01 2012 Introduction: Many studies have shown that amygdala kindling produces synaptic potentiation by induction of changes in the neuronal electrophysiological properties and inward currents both in epileptic focus and in the areas which are in connection with the epileptic focus and have important role in seizure development and progression such as hippocampal CA1 region. However, cellular mechanisms of these processes are not clear. In the present study, changes in the electrophysiological properties of hippocampal CA1 pyramidal neurons following amygdala kindling were examined in rat. Methods: Animals were rapidly kindled by stimulation of right amygdala (12 stimulation per day, 1 ms pulse duration at 50Hz). Twenty-four hours after amygdala kindling, electrophysiological properties and inward currents of CA1 pyramidal neurons were assessed by using whole-cell patch clamp technique. Results: Amygdala kindling findings show that percentage broadening of the last spike compared to the first spike during a trains of action potentials was significantly increased in kindled rats (p<0.05). The number of rebound action potential was significantly increased from 1±1 in control rats to 6±1 in kindled rats (p<0.01). The amplitude of post stimulus afterhyperpolarization potential (Post AHP) following a trains of action potential was also significantly (p<0.05) increased in kindled group (-5±2mV) compared to normal rats (-3±1mV). Under voltage clamp condition, amygdala kindling produced a significantly larger inward current (-5344.25±33.19 pA, p<0.001) in CA1 pyramidal neurons compared to normal cells (-9203.6±44.99pA). Conclusion: The present findings show that amygdala kindling resulted in neuronal hyperexcitability through alteration of the electrophysiological characteristics possibly by increasing the inward currents in hippocampal CA1 pyramidal neurons. 803 Cardiovascular Physiology/Pharmacology Effect of losartan on NOX2 transcription following acute myocardial ischemia-reperfusion Safari Fatemeh Hajiadeh Sohrab Moshtaghion Seyed Hosein Forouzandeh Moghadam Mehdi Shekarforoush Shahnaz Bayat Gholamreza Mazlum Roham Sattarian Leila 1 4 2012 16 1 44 53 17 12 2011 04 03 2012 Introduction: Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-2 (Nox2) is one of the predominant sources of ROS production during myocardial ischemia-reperfusion and can be induced by angiotensin II. The evidence suggests that pharmacological blockers of renin-angiotensin system can exert direct tissue effects independent of their ability to regulate blood pressure. The mechanism(s) responsible for such direct effects are not well understood. The aim of this study was to investigate the early changes of cardiac NOX2 gene transcription after myocardial ischemiareperfusion in rats treated with losartan, an angiotensin type 1 (AT1) receptor blocker. Methods: Wistar rats were divided into five groups: Control, sham operated, ischemia-reperfusion (group IR), losartan without ischemia and losartan with ischemia-reperfusion. The animals underwent 30 min of left anterior descending artery occlusion and subsequent reperfusion for 180 min. The mRNA expression was determined by real time-PCR in ischemic area of the left ventricle (LV) and non ischemic area of right ventricle (RV). Results: Compared to control hearts, exposure to myocardial ischemia-reperfusion produced a significant increase in NOX2 mRNA level in ischemic area of LV (P<0.001) but not in non ischemic area of right ventricle. Although in losartan group, NOX2 mRNA levels neither in LV nor RV were significantly altered, while in losartan and ischemiareperfusion group NOX2 mRNA upregulation in ischemic area was significantly suppressed (P<0.01). Conclusion: Based on the obtained results, it could be concluded that following acute myocardial ischemia– reperfusion, NOX2 mRNA levels were increased in ischemic area of left ventricle but not in non ischemic area of right ventricle, suggesting the local effect of ischemia on the gene expression. Furthermore, inhibition of NOX2 transcription in ischemic area may be a mechanism of the anti ischemia effects of losartan. 768 Others Evaluation of UCP2 expression in the phenomenon of ischemic resistance induced by alternating normobaric hyperoxia in a rat model of stroke Alavian Firoozeh Hajizadeh Sohrab Bigdeli Mohammad Reza Bayat Gholam Reza Javan Mohammad Tarbiat Modares University Tarbiat Modares University Shahid Beheshti University Tarbiat Modares University Tarbiat Modares University 1 4 2012 16 1 54 61 27 10 2011 23 04 2012 Introduction: ischemic preconditioning is one of the most important mechanisms, responsible for the increased brain resistance after stroke. One of the most important candidates to ischemia preconditioning is intermittent normobaric hyperoxia. In this study, the effect of intermittent normobaric hyperoxia on the expression of UCP2 was investigated in a stroke model. Methods: Rats were divided into 4 groups (normoxia – sham, hyperoxia – sham, normoxia – stroke and hyperoxia – stroke). Hyperoxia groups were exposed to 95% inspired O2, for 4 h/day and 6 consecutive days. Oxygen level in the control groups was %21 (normoxia). After 24 h, stroke groups were subjected to 60 min of right middle cerebral artery occlusion. After 24 h reperfusion neurological deficit scores were assessed. The brain UCP2 levels were analyzed by western blot. Results: The results of this study showed that following brain ischemia-reperfusion, UCP2 levels significantly increased in the stroke groups compared with the sham group while there was no significant difference in hyperoxia groups compared with normoxia. Also hyperoxia decreased neurological deficit scores. Conclusion: Following ischemia, oxidative stress caused by increase of ROS, leads to increased UCP2 levels in stroke groups. In this study, the neuroprotective effect of hyperoxia is independent of UCP2 expression. 816 Endocrine Physiology/Pharmacology Effect of Vitex agnus-castus fruits hydroalcoholic extract on sex hormones in rat with induced polycystic ovary syndrome (PCOS) Jelodar Gholamali Askari Kobra shiraz University Payam Noor University 1 4 2012 16 1 62 69 07 02 2012 21 04 2012 Introduction: PCOS is an important reproductive and endocrine disorder in women in the reproductive age. Present reports indicate that Vitex agnus-castus acts through hypothalamus-pituitary axis. This study was carried out to evaluate the effects of Vitex fruit hydroalcoholic extract on the alteration of sex hormones in a PCOS animal model. Methods: Following 14 days of monitoring of estrous cycles of rats, 32 animals with regular cycles were selected and randomly divided into four groups as follows: Control, treatment-control or sham (received 365 mg/kg Vitex extract for 30 days), PCO (received letrozole 1mg/kg for 28 days to induce PCOS) and PCT (treated with Vitex extract 365 mg/kg for 30 days after induction of PCOS). On the last day of experiments, estrous cycles of all animals were detected and blood was collected by heart puncture for evaluation of hormone levels. Results: The results showed that serum estradiol and progesterone levels decreased, while testosterone and DHEA levels increased following induction of PCO. No significant changes were observed in the hormone levels of the sham group compared to control. In the group treated with Vitex extract, a significant increase in serum levels of progesterone and a significant decrease in the serum testosterone levels were observed, however serum levels of estrogen and DHEA did not change significantly. Conclusion: Vitex agnus-castus fruit extract can improve serum levels of testosterone and progesterone in an animal model of PCOS, however it cannot change estrogen and DHEA levels significantly. 764 Endocrine Physiology/Pharmacology Effect of ICV injection of ghrelin and leptin on T3 and T4 plasma levels in Rat Amoo-Rajabi Ommolbanin Moghimi Ali Khazali Homayoon 1 4 2012 16 1 70 78 26 09 2011 22 02 2012 Introduction: Ghrelin, increases food intake, decreases T3 and T4 concentrations and stimulates insulin release, while leptin reduces food intake and suppresses appetite. Considering the importance of thyroid hormones, ghrelin and leptin in body metabolism, the purpose of this study was to investigate the effect of interactions between ghrelin and leptin (injected via ICV route) and plasma T3 and T4 concentrations in rats. Methods: Fifty-six Wistar male rats (230 to 250 g/BW) were randomly divided into 7 groups. Groups 1, 2 and 3 received 1, 3 and 5 nmol ghrelin, while groups 4, 5 and 6 received 1, 5, 10 nmol leptin (2 μl via lateral cerebral ventricle). Animals in the 7th group received 5 nmol ghrelin with 10 nmol leptin via the same route for 3 days. Blood samples were collected daily starting from one day before until one day after infusions and plasma samples were used to assess T3 and T4 concentrations by RIA. To ensure proper cannulation, perfusion and brain slices were performed. Results: The results indicated that ghrelin significantly decreased T3 and T4 concentrations, whereas leptin increased these concentrations. The simultaneous injection of ghrelin and leptin significantly reduced the inhibitory effect of ghrelin on thyroid hormones concentrations. Conclusion: According to the results and other researchers’ suggestions, the opposite effects of leptin and ghrelin could be emphasized and some hormonal mechanisms for these 2 hormones (transmitters) such as HPA and/or HPT axes or MSH systems could be suggested. 805 Others Alterations in dopamine related behavior of the offspring of pregnant Wistar rats exposed to noise pollution stress Hassanvand Tayebeh Balooch Mohammad Azarnia Mahnaz Zardooz Homeira Erfani Marjan Hosseini Seyedeh Yassaman Sahraei Hedayat 1 4 2012 16 1 79 85 22 12 2011 03 04 2012 Introduction: Effects of stress on nervous system activity and development are well defined. In the present study, the effects of maternal stress on dopamine-related behavior in the offspring were studied. Methods: Female pregnant Wistar rats (200 g) were randomly exposed to the noise pollution stress (125 db) for 14 days (5 min/day). The time of exposure was random in order to avoid adaptation. The offspring were nursed by their mothers until the adolescence (200 g-3 mounts of age). These animals were examined for their seeking behavior including rearing, sniffing and locomotion using open field method. Twenty four hours later, they received subcutaneous administration of the dopamine D2 receptor antagonist, sulpiride (5 mg/kg) for evaluation of dopamine receptor sensitization. Results: Our results showed that sniffing was reduced (P<0.01), but both rearing (P<0.05) and locomotion (statically non significant) activity in the F2 of stress group was increased. Injection of sulpiride reduced animals activity (sniffing, rearing and locomotion) in both groups but the reduction was more pronounced in the stress group (P<0.001). Conclusion: It could be concluded that dopamine-related behavior differed in the experimental group, which was exposed to stress during intra-uterine life. In addition, the experimental group showed a pronounced response to sulpiride, which may be due to alteration in brain dopamine system activity in these animals. 790 Others Effect of repeated morphine and tramadol administration on the motor behavior in the neonatal period Gholami Morteza Zare Samad 1 4 2012 16 1 86 94 22 11 2011 16 01 2012 Introduction: Motor behavior and coordination impairment are known side effects of opioid treatment, yet very few studies have investigated the effects of tramadol on motor behavior, or compared its effect with the effect of an opioid. This study investigates the effects of chronic injection of morphine and tramadol on rat motor function during infancy. Methods: Neonate rats (n=56) were randomly divided into three groups. On postnatal days 8-14, one group received saline and two other groups received tramadol and morphine with a dose-dependent manner. On postnatal day 21, each group was divided into subgroups, which received morphine, tramadol or saline again on postnatal days 22-26. Finally, on postnatal days of 22 and 26, the motor behavior was studied. Results: On postnatal day 23, tramadol caused an increase the falling rate from Rotarod (P<0.001), But there was not any significant difference between morphine groups. On postnatal day 26 rat, there was a significant difference only for morphine groups that received additive doses. Conclusion: The last dose of morphine (15 mg/kg) interferes with motor behavior of immature rats, whereas tramadol with additive doses on the first two days (3-6 mg/kg) caused an impairment in motor behavior of immature rats, but could not maintain this ability for the rest of the days of the injection (until 26 day).