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Showing 12 results for Sheibani

Jila Behzadi, Vahid Sheibani, Hossein Esteky, Farzaneh Ganji,
Volume 6, Issue 1 (Spring and Summer 2002)

Behavioral and electrophysiological evidences have shown that locus ceruleus (LC) is involved in different tasks including modulation of sensory processing and shift of attention. In the present study, single unit responses of barrel cortical cells was recorded following controlled mechanical displacement of the principal and peripheral vibrissae in adult rats (100 trials of 200 µm deflection for 10 ms at 1/1.5 second). Mechanical displacement was performed alone and 50 ms after electrical stimulation (10 pulses, 300 µs, 30 µA, 40 Hz) of LC. The onset of evoked responses was defined as the time when spontaneous activity exceeded its mean by two standard deviations. Then, analysis of response latency and response magnitude for periods of 10 and 50 ms following the initiation of evoked response was performed. Response magnitude to principal vibrissae deflection in a period of 10 ms decreased significantly after LC phasic stimulation (p<0.01), but there was no significant difference for a period of 50 ms. In addition, for both time periods, there was no significant differences for response magnitude to peripheral vibrissae deflection before and after LC phasic stimulation. Response latency to principal vibrissae deflection increased significantly after LC stimulation, but it decreased significantly when peripheral vibrissae were deflected (p<0.05). These results support the idea that LC phasic activation has an important role in cortical somatosensory information processing through modulating the receptive field characteristics of cortical neurons.
Vahid Sheibani, Sahel Motaghi, Rasool Farazifard, Hossein Joneidi, Mohammad Reza Afarinesh,
Volume 10, Issue 2 (Summer 2006)

Introduction: It is believed that Locus Coeruleus (LC) influences the sensory information processing. However, its role in cortical surround inhibitory mechanism is not understood. In this experiment, using controlled mechanical displacement of whiskers we investigated the effect of phasic electrical stimulation of LC on response of layer V barrel cortical neurons in anesthetized rat. Methods: LC was stimulated 0, 50, 100, 200 and 400ms before principal or adjacent whiskers deflection. For assessing the effect of LC stimulation on inhibitory receptive field of the barrel neurons, adjacent whisker was also deflected 20ms before principal whisker deflection, and LC stimulation was applied 0-400ms before principal whisker displacement. Results: We found that LC stimulation increased the response magnitude of layer V neurons to principal whisker deflection (significance level (p<0.05) at 50-400ms intervals). This increase in response magnitude was observed to adjacent whisker deflection too (significant (p<0.01) at 100ms interval). The response latency of neurons was decreased when LC was stimulated 400ms before principal whisker deflection (p<0.01). LC stimulation did not affect the neuronal response latency to adjacent whisker displacement or spontaneous activity of neurons. Inhibitory effect of adjacent whisker deflection on neuronal response magnitude was increased by LC stimulation when tested when combined whisker displacement. Conclusion: These findings suggest that LC by modulating the neuronal responses enhances the neuronal responsiveness to sensory stimuli and increases their surround inhibition in cortex.
Ali Shamsizadeh, Vahid Sheibani, Yaghoub Fathollahi, Mohammad Javan, Javad Mirnajafi-Zadeh, Mohammad Reza Afarinesh,
Volume 11, Issue 2 (Summer 2007)

Previous studies have shown that the receptive field properties, spontaneous activity and spatio-temporal interactions of low-threshold mechanical somatosensory cells in the barrel cortex are influenced by C-fibers. In this study, we examined the effect of C-fiber depletion on response properties of barrel cortex neurons following experience dependent plasticity. Methods: In this study, exteracellular single unit recording was performed on 154 barrel cortex neurons in 70 male Wistar rats (38-41days old). For depleting of C-fibers, neonatal rats received an intra-peritoneal injection of capsaicin solution (50 mg/kg) on the first neonatal day. For induction of experience dependent plasticity, all whiskers but D2 on the left muzzle, were plucked from first neonatal day. Neuronal ON and OFF responses were recorded in right barrel cortex following principal whisker (PW) and its caudal adjacent whisker (AW) deflection. Results: Whisker plucking increased PW–evoked ON responses both in capsaicin and vehicle treated rats (all P<0.05). In vehicle treated rats, AW-evoked ON responses were decreased in plucked animals (P< 0.05). Of particular interest, in capsaicin treated rats, AW-evoked ON responses were not decreased in plucked animals. Analyzing OFF responses showed similar result to ON responses. Conclusion: These findings indicate that c-fibers can modulate neuronal response properties following experience dependent plasticity in layer IV of barrel cortex.
Jamal Ghorbi, Mohammad Javan, Vahid Sheibani, Leila Satarian, Amir Zarebkohan,
Volume 11, Issue 2 (Summer 2007)

There is some evidence supporting the reduced activity of integrins following chronic administration of morphine. This reduction might play a role in morphine tolerance development. Manganese binds to the extracellular domain of integrins and makes them to be activated. The effect of integrins activation using manganese on tolerance development to the analgesic effect of morphine was investigated in this study. Methods: To induce tolerance to analgesic effect of morphine, morphine (15 μg/rat) was injected intrathecally (i.t.) to male adult Wistar rats twice a day for five days. To investigate the effect of manganese, it was injected (20 nmol/rat-i.t.) 15 minutes prior to morphine injections during mentioned period. The analgesic effect of morphine (15 μg/rat) was measured using tail flick test on day 6. Results: The results indicated that in animals which received both manganese and morphine during first 5 days, morphine induced a significant analgesia on day 6. Chronic administration of manganese did not change the pain threshold and morphine induced analgesia. Comparison of morphine analgesia following a single dose of morphine (15 μg/rat) or chronic manganese+morphine, indicated that manganese did not have any effect on the morphine analgesia. Conclusion: Our results showed that, manganese administration prior to morphine is able to prevent morphine tolerance development. It seems that decreased activity of integrins following chronic administration of morphine plays a pivotal role in tolerance development to morphine analgesia. Further investigation needs to determine whether manganese effect is dependent on the integrins role in cell adhesions, or on their intracellular signaling pathways.
Tahereh Zeinali, Javad Mirnajafi-Zadeh, Vahid Sheibani, Mohammad Eza Palizvan, Mehdi Abbasnejad,
Volume 11, Issue 3 (Fall 2007)

Epilepsy is among the most common disorders of the central nervous system and there is not an absolute method for its treatment. It has been shown that each seizure has a depressing effect on the following seizure. Thus, finding the mechanisms responsible in this phenomenon can improve our knowledge toward new ways for epilepsy treatment. In this study, the role of adenosine A1 receptors in post seizure depressing period was investigated in amygdala kindling model of epilepsy. Methods: Rats were kindled by daily electrical stimulation of amygdala. At first, different groups of kindled animals were stimulated at different times after the first stimulation and the percent of suppression of seizure parameters were calculated. Then, 8-cyclopenthyl-1, 3-dimethylxanthine (CPT), a selective adenosine A1 receptor antagonist (50 and 200 μM) were intracerebroventricularly microinjected before the second stimulation and its effect on percent of suppression induced by the first stimulation was investigated. Results: In the second stimulation, applied at 10 and 30 min after the first stimulation, the seizure parameters were significantly reduced. CPT microinjection (50 and 200 μM) significantly decreased the percent of suppression of seizure parameters. This decrease was significant at 10 and 30 min after the first stimulation with compare to the groups received the drug solvent. Conclusion: Obtained results showed that endogenous adenosine has a role in post seizure depression period through A1 receptors. As the blocking of A1 receptors by CPT could not completely prevent this period, other factors may also play role in this suppression.
Vahid Sheibani, Somaye Arabzadeh, Mohamadreza Afarineshkhaki, Ali Shamsizadeh, Hossein Aminizadeh, Saeed Azizolahi,
Volume 11, Issue 4 (Winter 2008)

Introduction: Barrel cortex of rats is a part of somatosensory cortex, which receives information from facial whiskers. Vibrisectomy by sensory deprivation leads to some changes in the barrel cortex, which have been known as experience dependent plasticity. On the other hand, Norepinephrine (NE) and locus coeruleus, which is the main source of NE, influenced response properties of cortical barrel neurons. In this study, the effect of NE depleted and sensory deprivation on induction of experience dependent plasticity was investigated. Materials and methods: In this study sixty wistar rats (250±25gr) were used. Rats were divided into four groups: 1.Control group (Intact). 2. NE depleted group in which Norepinephrine was selectively depleted by IP injection of DSP4. 3. Sensory deprivation group that all whiskers (except the whisker D2) on the left side were trimmed every other day. 4. NE depleted + sensory deprivation group. By using extracellular single unit recordings, the excitatory (magnitude and latency) and initiatory (Conditioning Test Ratio, CTR index) receptive fields of barrel cortical neurons were calculated. Results: Sensory deprivation led to an increase both in the response magnitude to principle whisker deflection (spared whisker) and in the CTR. In NE depleted + sensory deprivation group, the response magnitude and CTR index were the same as control group. Conclusion: The result showed that experience dependent plasticity has a facilitating effect on excitatory receptive field while decreasing the inhibitory circuits in the brain. When NE content of the brain was depleted before sensory deprivation, these changes were not seen. We conclude that NE depletion inhibits the plastic changes in the response properties of neurons following sensory deprivation.
Mohammad Shabani, Masoud Haghani, Vahid Sheibani, Mahyar Janahmadi,
Volume 13, Issue 2 (Summer 2009)

Abstract* Introduction: Cannabis consumption during pregnancy may affect fetal growth, motor performance, memory and cognitive functions. Methods: Primiparous pregnant Wistar rats were randomly assigned to 4 treatment groups (6 rats per group) consisting of control and sham groups as well as 2 groups treated with Win. Win treated groups received daily s.c. injections of 0.5 or 1 mg/kg WIN suspended in 1% Tween 80 saline in a volume of 1 ml/kg from days 5 to 20 of pregnancy. Sham treated rats were given daily injections of 1% Tween 80 saline on the same days of pregnancy. Body weight, mortality, memory function and motor performance were assessed in the infants on the third, fifth and seventh weeks after birth. Righting responses in rat pups were also compared on the second day after birth. Results: Offsprings from Win (1mg/kg) treated rats exhibited a significant loss in the righting reflex on the 2nd day after birth, when compared to other groups. However, there was no statistically significant difference between groups regarding motor coordination assessed by rotarod test on the 3rd and 5th weeks after birth. Passive avoidance learning (PAL) test on 50-day-old rats showed that during the acquisition trials, approach latencies were not significantly different among all groups. However, in retention trials, which were performed 24 h and 7 days later, the avoidance latencies of rats exposed to 0.5 mg/Kg Win were significantly shorter than those of the control and sham animals. Win consumption during pregnancy did not induce significant changes in the body weight of pregnant rats on the first day and three weeks after pregnancy. Litter size (number of pups per delivery) was significantly reduced in 1 mg/kg Wintreated compared to 0.5 mg/kg Win-treated, sham treated and control groups (p<0. 001). The length of pregnancy in 1 mg/kg Win-exposed rats was also significantly shorter compared to control (p<0.001), 0.5 mg/kg win-treated (p<0.01), and sham (p<0.0001) rats. Conclusion: These findings suggest that prenatal exposure to Win, a cannabinoid agonist, probably induces a longterm alteration of the endocannabinoid system, which in turn affects learning and motor coordination ability. Keywords: Cannabinoids, Maternal Consumption, motor performance, memory.
Ali Siyahposht Khachaki, Vahid Sheibani, Mohammad Reza Afarinesh Khaki, Hamid Sheikhkanloui Milan, Ali Shamsizadeh,
Volume 13, Issue 4 (Winter 2010)

Introduction: Barrel cortex of rodents is responsible for sensory information processing from muzzle whiskers. Locus coeruleus (LC) as the main source of norepinephrine (NE) in the cortex, is effective on the sensory information processing. Methods: Rats were divided to 2 groups. One group underwent sensory deprivation (P4) and the other group served as control and did not undergo sensory deprivation. Response properties of the neurons were evaluated by extracellular single unit recordings following a controlled mechanical deflection of the principal whisker (spared whisker), or before the simultaneous deflection of principal and adjacent whiskers (trimmed whisker) were assessed. In the P4 group, all whiskers on the left muzzle, except D2, were trimmed every other day for two months. In both groups, LC was electrically stimulated 0, 50, 100, 200, 400 and 800 ms before controlled principal whisker deflection. Response magnitude, latency and CTR index (lateral inhibition index) were assessed. Results: In the P4 group, deflection of the principal whisker without LC electrical stimulation, increased the response magnitude and CTR index, but decreased the response latency compared to the control group. The magnitude of the response of neurons to the principal whisker deflection was significantly different between P4 and control groups, in following of principal whisker deflection in times of LC stimulation showed significant difference only in 50 ms subgroup. In both groups, pro-stimulation differences in CTR index and response latency remained unchanged after LC stimulation. Conclusion: Our data showed that electrical stimulation of LC following sensory deprivation modulates neuronal response properties and changes their response pattern.
Jamal Ghorbi, Mohammad Javan, Vahid Sheibani, Amir Zarebkohan,
Volume 14, Issue 2 (Summer 2010)

Introduction: In order to study the alterations of beta 1 and 2 integrins mRNA level in rat lumbar spinal cord following the induction of chronic pain and its effect on the development of tolerance to morphine analgesia, we examined the level of expression of these genes in the presence of chronic pain, which is an inhibitor of morphine tolerance. We used induction of chronic pain alone and in combination with morphine administration. Methods: In order to induce tolerance to analgesic effect of morphine, morphine (15 μg/rat) was intrathecally (i.t.) injected to male adult Wistar rats twice a day for 4 days. Chronic pain was induced using formalin %5, 15 minutes before morphine injections during days 1-4. The analgesic effect of morphine was measured using tail flick test. Lumbar spinal tissues were assayed for the expression of beta-1 and 2 integrins using ‘‘semi-quantitative RT-PCR’’ and were normalized to beta-actin. Results: Chronic administration of morphine for 4 days developed tolerance to morphine analgesia. Concomitant induction of pain with morphine administration inhibited the development of tolerance to the analgesic. Induction of chronic pain, 15 minutes before morphine injections resulted in significant increases in beta-1 and 2 integrins mRNA levels. Furthermore, chronic pain alone also resulted in increased beta-1 and 2 integrins mRNA. Conclusion: Our results showed that, the induction of chronic pain prior to morphine administration, which is able to prevent morphine tolerance, increases the expression of integrins. Chronic morphine administration resulted in increases of beta 1 and 2 integrins mRNA level in lumbar spinal cord. It may be suggested that increases of beta-1 and 2 integrins mRNA is the result of the negative feedback of integrin inhibition by chronic morphine administration. Chronic pain is an enhancer of beta-1 and 2 integrins and its simultaneous presence with morphine administration results in increased beta-1 and 2 integrins and as a result prevents the development of morphine tolerance.
Mojtaba Khodami, Mehdi Abbasnejad, Vahid Sheibani, Mina Mobasher, Mitra Mehrabani, Akbar Anaie Goodary, Sahar Salari,
Volume 15, Issue 3 (Fall 2011)

Introduction: Dracocephalum polychaetum bornum is exclusively found in a limited geographical area in the Kerman province It is used by the local people for treatment of abdominal pain, meteorism and musculoskeletal pain. No study has been performed on the effects of D. polychaetum bornum, so the aim of this work was to assess the role of the extract and essential oil of this plant on pain and anxiety assessed by formalin test and elevated plus-maze (EPM), respectively, in male rats. Methods: Analgesic effects: One hundred twelve NMRI male rats were divided into 14 groups. Aqueous extract and essential oil were administered to 8 groups at doses of 25, 50, 100 and 200 mg/kg i.p., while 2 groups were treated with normal saline, and the last 4 groups (sham positive) received ASA (300 mg/kg) and morphine (2.5 mg/kg). Anxiolytic effect: Forty-two NMRI male rats were divided into 7 groups. Four groups were injected intraperitoneally with 25, 50, 100 and 200 mg/kg of the extract of the plant and 2 groups were injected with normal saline (control group) and 1 mg/kg diazepam (positive sham). Anxiolytic effect was evaluated by EPM. Results: The results showed that the extract but not the essential oil at the dose of 200 mg/kg had a significant analgesic effect 25, 30 and 35 minutes after administration. The findings on the anxiolytic effect revealed that there was no significant difference between groups treated with different doses. Conclusion: This study showed that D. polychaetum bornum had analgesic effects.
Khadijeh Esmaeilpour, Vahid Sheibani, Hakimeh Saadati,
Volume 19, Issue 2 (June 2015 2015)

Previous studies have shown that caffeine has beneficial effects on cognitive impairment in sleep deprived male rats. Therefore in the present study, we examined the effects of chronic caffeine administration on learning and memory impairments induced by sleep deprivation (SD) in the intact and ovarectomized (OVX) female rats. Two sets of animals including intact and OVX were randomly recruited into the following subgroups: control, SD, wide platform (Sham platform), caffeine, and caffeine plus SD. Multiple platform method was used for SD induction. Spatial learning and memory were determined using Morris water maze (MWM) task. Throughout behavioral investigation, significant learning impairment was observed in sleep-deprived OVX rats compared to the intact and the other OVX groups (P<0.05). Short term memory impairment was observed in both sleep-deprived OVX and intact groups (P<0.05). 4weeks caffeine administration improved these impairments. Based on these findings we propose that sleep deprivation impaired cognitive function whereas caffeine treatment reversed these impairments.

Mohammad Reza Afarinesh, Baharak Akhtardanesh, Tahereh Haghpanah, Fatemeh Golshan, Gholam Hossein Meftahi, Niousha Ghanbarpour, Ayoob Fakhri, Saeed Sheikhshoaei, Vahid Sheibani,
Volume 22, Issue 3 (September 2018)

Introduction: Noise pollution is an unwanted inevitable distribution of the modern and industrialized life of mankind. With the expansion of urban life, humans are daily exposed to noise pollution which can cause anxiety and disorders in cognitive activities. The present study was aimed to investigate the impact of sub-chronic urban traffic noise pollution on learning, memory and anxiety-like behavior in adult male rats. Methods: Thirty two adult male Wistar rats (weighing 275-300g) were used in the present experimental study. The animals were divided into two groups: the control and the noise-exposed. The rats in the test group were exposed to a 90dB noise recorded from a crowded street traffic for 6h/10 days. Control rats were intact. Morris water maze (MWM) and an elevated plus maze (EPM) were used to assess spatial learning and memory and anxiety-like behavior in rats. Results: The findings displayed that both control and noise-exposed group improved their maze steering over 4 days of experiment in MWM; however, noise-exposed group had more latency and traveled-distance in MWM to find the hidden platform in probe trial compared to those of control (P<0.05). Moreover, noise-exposed group showed a significant increase in weight gain compared to the control group (P<0.05). In addition, the spent time in open arm of the EPM was significantly decreased compared to controls (P<0.05). Conclusion: Urban traffic noise pollution for a short-term period causes a meaningful increase on weight gain, disorders in retrieval memory and increase in anxiety-like behavior in rats.

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