32 24765236 Iranian Society of Physiology and Pharmacology 605 Pharmacokinetics/Dynamics Acute Administration of Estradiol Protects against Spinal Ischemic-Reperfusion Injury in Male Rabbits Khalaj Leila Peirovi Habibollah Khaodagholi Fariba Abdi Azadeh Dargahi Leila mohagheghi fatemeh Ahmadiani abolhassan 1 3 2010 14 1 1 11 27 01 2010 15 05 2014 Introduction: Postoperative neurological deficit is the most devastating complication after thoracoabdominal aortic aneurysm repair. Despite demonstrated neuroprotective effects of estradiol, its protective efficacy against spinal cord ischemia-reperfusion and underlying mechanisms are not yet elucidated. Methods: Two groups, each of 10 New Zealand white male rabbits, were studied. Control group received sesame oil (vehicle) while the treatment group received 17-β-Estradiol Cypionate (1 mg/kg) dissolved in sesame oil, 30 minutes before abdominal aortic clamping for 18 minutes. A group of sham operated animals was also included, which consisted of 5 rabbits subjected to operative dissections without aortic occlusion. After 48 h reperfusion we investigated the efficacy of estradiol in attenuating the spinal cord ischemia-induced pathology through neurological, histopathological, and western blot assessments. Results: The results showed that administration of estradiol 30 minutes before induction of spinal cord ischemia in rabbits improved functional outcome and prevented the worsening pattern of neurological function over 48 hours. Near to normal histopathological outcome of lumbar part of spinal cords in these animals confirmed neuroprotective effects of estradiol. Estradiol also reduced spinal cord Heat shock protein 70 and cleaved caspase-3 in this ischemic context. Conclusion: Estradiol can be considered as a potential candidate to protect against spinal cord ischemiareperfusion- induced paraplegia resulting from thoracoabdominal aortic aneurysm repairs.
583 Cardiovascular Physiology/Pharmacology Effect of nitric oxide modulation on the basic and rate-dependent electrophysiological properties of AV-node in the isolated heart of rabbit: The role of adrenergic and cholinergic receptors Khori Vahid Davarian Ali Nayebpour Mohsen Saleki Saeed Salehi Aref Shirafkan Ahmadali Badaghabadi Fakhri Pourabouk Mona Alizadeh Alimohammad Changizi Shima 1 3 2010 14 1 12 22 15 10 2009 15 05 2014 Introduction: Recent studies showed that nitrergic system have specific modulatory effects on electrophysiological properties of atrioventricular (AV) node. The aim of this study was to determine the effects of nitric oxide (NO) on the electrophysiological properties of isolated rabbit AV node and to investigate the role of adrenergic and cholinergic receptors in the mechanism of its action. Methods: In our laboratory, an experimental model of isolated double-perfused AV-node of rabbits weighing 1.5-2 kg was used. Specific experimental protocols of recovery, Facilitation, Fatigue and Wenckbach were applied in both control and in the presence of the drug. A total number of 35 rabbits were divided randomly into the following groups (n=7): 1) L-Arg (NO donor) (250, 750 and 1000 μmol), 2) L- NAME, a NO synthesis inhibitor (25, 50 and 100 μmol), 3) L-Arg + L- NAME, 4) Nadolol (1 μmol), 5) Atropine (3 μmol). All data were shown as mean ± SE. The level of statistical significance was set at p<0.05. Results: Our results revealed the depressant effect of L-Arg on the basic and rate-dependent electrophysiological properties of AV-node. L- NAME did not deteriorate the effects of L-Arg on the basic and rate-dependent properties, nevertheless, at high concentration (100 μmol) it had a direct inhibitory effect on the AV-node. Nadolol and atropine could prevent the effects of NO on the basic nodal characteristics and the fatigue phenomenon, respectively. Conclusion: Nitergic system can affect basic and rate-dependent electrophysiological properties of the AV-node through adrenergic and cholinergic receptors. 588 Cardiovascular Physiology/Pharmacology Inhibition of nitric oxide synthase activity improves focal cerebral damage induced by cerebral ischemia/reperfusion in normotensive rats Mohammadi Mohammad Taghi Shid Moosavi Seyed Mostafa Dehghani Gholam Abbas 1 3 2010 14 1 23 33 18 11 2009 15 05 2014 Introduction: Nitric oxide seems to play a dual role in ischemia/reperfusion injury. Few studies have investigated whether it exacerbates or improves brain edema. In the present study, we inhibited the activity of nitric oxide synthase by L-NAME and evaluated the cerebral infarct volume, tissue swelling and brain edema, alongside the measurement of blood flow of the ischemic region. Methods: Transient focal cerebral ischemia was induced by 60 min middle cerebral artery occlusion followed by 12 hours reperfusion in rat. Experiments were performed in three groups of rats (n=12 each) Sham, control ischemic, and L-NAME pretreated (1 mg/kg IP). Laser Doppler flowmetry was used to measure the regional blood flow. After neurological deficit score (NDS) testing, the brains were prepared for TTC staining or brain water content technique to measure the infarct volume and brain edema. Results: Pretreatment with L-NAME significantly reduced NDS (3.66 ± 0.33 to 1.5 ± 0.34), infarct volume of cortex (374 ± 34 to 160 ± 41 mm3) and striatum (158 ± 15 to 87 ± 16 mm3), tissue swelling (7.35 ± 1.27% to 4.05 ± 0.91%) and brain edema (3.5 ± 0.48% to 1.6 ± 0.6%) without significant alteration of blood flow of the ischemic region. Conclusion: The findings of this study indicate that inhibition of nitric oxide synthase activity reduces infarct volume and brain edema of the ischemic region induced during 60 min middle cerebral artery occlusion. This effect is not accompanied with any alteration in the blood flow of the ischemic region. 576 Others Effect of intracerebroventricular injection of flunixin meglumine on PTZ-induced seizures in male rats Garavand Soheila Keramati Keivan Zendehdel Morteza Jadidoleslami Mahin Garavand Sedigheh 1 3 2010 14 1 34 40 21 08 2009 15 05 2014 Introduction: Flunixin Meglumine (FM) is a nonsteroidal antiinflammatory drug (NSAID) and nonselective cyclooxygenase (COX) inhibitor. Since it has been suggested that COX enzyme plays a role in seizure, this research is performed to assess the therapeutic effects that this compound might have in seizures induced by PTZ. Methods: In this research, male wistar rats (200 ± 20 g) were given intracerebroventricular injections of saline or FM (12.5 μg, 25 μg and 50 μg) in a 1 μl volume, before intraperitoneal administration of PTZ (80 mg/kg) for induction of seizure. Then, seizure score and times of onset for every stage of seizure were recorded during 20 minutes after PTZ administration. The data were analyzed by one-way analysis of variance (ANOVA). Results: injection of 25 and 50 μg of FM significantly increased times of onset of every seizure stage compared to the control group. The group that received 50 μg of FM did not show stage 5. On the other hand, 12.5 μg FM group did not show any significant difference with the control group. Conclusion: We conclude that FM has dose dependent anticonvulsive properties. 597 Others Intermediary role of kisspeptin in the stimulation of gonadotropin-releasing hormone neurons by estrogen in the preoptic area of sheep brain Jafarzadeh Shirazi Mohammad Reza Tamadon Amin 1 3 2010 14 1 41 47 03 01 2010 15 05 2014 Introduction: The role of estrogen in the stimulation of gonadotropin-releasing hormone (GnRH) neurons is clear. These neurons do not express estrogen alpha receptors, so other mediator neurons should be present to transmit the positive feedback effect of estrogen to the GnRH neurons. Kisspeptin neurons have an important role in the stimulation of GnRH neurons, so they can be the mediator of the effect of estrogen on GnRH neurons in preoptic area of sheep brain. One of the known effects of estrogen is the stimulation of Fos gene in the brain. The aim of the present study was to determine the intermediary role of kisspeptin in the transmission of estrogen effects to the gonadotropin-releasing hormone neurons in the preoptic area of sheep brain. Methods: Six mature ewes in breeding season were selected and ovariectomised. Three ewes in treatment group were injected with 50 mg estradiol benzoate in 1 ml of sunflower oil and three ewes in control group were injected with saline solution intramuscularly. Immediately after estradiol injections, the hypothalamus of the ewes was removed. The count of kisspeptin neurons, Fos genes, and kisspeptin neurons which colocalized with Fos genes were determined by immunohistochemistry. Results: Estradiol injection increased the colocalization of kisspeptin with Fos gene in the preoptic area of the sheep brain (P=0.01). Results of the present study showed that 86.9 percent of kisspeptin neurons colocalized with Fos gene in the preoptic area (P=0.01). Conclusion: Kisspeptin neurons are important mediators in transmission of positive feedback effect of estrogen into GnRH neurons in the preoptic area of sheep brain. 615 Others Effects of congenital hypothyroidism on the morphology of trigeminal motoneuron assessed by the Golgi staining method in rats Sepehry Hamid Ganji Farzaneh 1. Department of Physiology, Faculty of Medicine, Golestan University of Medical Sciences and2. Golestan Neurosciense Research Center Department of Biology, Faculty of Sciences, Golestan University and 2. Golestan Neurosciense Research Center 1 3 2010 14 1 48 55 27 02 2010 15 05 2014 Introduction: Appropriate thyroid hormone (TH) levels are essential during the critical period of brain development, which is associated with the growth of axons and dendrites and synapse formation. In rats, oral motor circuits begin to reach to their adult pattern around 3 weeks after birth, the period in which alteration from sucking to biting and chewing occurs (weaning time). Trigeminal motor nucleus (Mo5) as the supplier of nerves that innervate jaw muscles, shows obvious developmental changes during this period. TH may have an important role in these changes. Methods: Time pregnant female rats received 50 ppm propylthiouracil (PTU) in their drinking water from 16th day of pregnancy, continued to 23rd day post partum, while control group received tap water. Brain stems of 6 male 23-dayold pups in each experimental group were processed for Golgi staining method. Using rotary microtome, brain stem paraffin embedded blocks were cut to 70 micron slices. Mo5 tissue sections were selected for photography and morphological analysis. Cell body measurements were performed using Starter image analyzer software. Modified Sholl’s concentric circles technique was used for the morphological analysis of the dendrites. Results: The results of cell body measurements revealed a significant decrease in the soma size of trigeminal motoneurons in hypothyroid pups. Besides, counting of the dendrites showed that the number of secondary, tertiary and higher order dendrites, but not primary dendrites, showed a significant decrease compared to the normal group. Conclusion: The important role of thyroid hormone in motoneurons development and neurofilaments formation suggests that congenital hypothyroidism can alter the cell size and dendritic arborization pattern of trigeminal motoneurons. 572 Cell, Stem Cell and Cancer Design, cloning, expression and evaluation of cysteine-substitutes of intact and truncated molecules of streptokinase Monzavi Nastaran Aghasadeghi Mohamad Reza Arabi Reza Memarnejadian Arash Sadat Mehdi Khanahmad Hossein Ebrahimi Melania Roohvand Farzin 1 3 2010 14 1 56 65 03 08 2009 15 05 2014 Introduction: Thrombosis and the blockage of blood vessels with clots, can lead to acute myocardial infarction and some times even death. Aside from surgical interventions to remove the blockage, the only available treatment is the administration of thrombolytic agents to dissolve the blood clot. Streptokinase (SK) is the most commonly used fibrinolytic drug for this purpose. However, SK has some disadvantages including immunogenicity, short half-life and hemorrhage induction. PEGylation of pharmaceutical proteins by the incorporation of cysteine amino acid is a novel method to decrease their immunogenicity and also to increase their stability and half-life. The ultimate goal of this study was designing and construction of the cysteine analogues of full-length and truncated forms of SK, which posses less hemorrhagic side effects due to fibrin specificity. Methods: By application of PCR-based site-directed mutagenesis technique, mutants of SK genes, harboring the transversion of AGC codon (serine) to TGC (cysteine), which encoded full-length (amino acids 1-414) and truncated (amino acids 60-386 and 143-386) proteins were established and cloned in pET41a plasmid. Expression of the recombinant SKs was achieved through the induction of E. coli transformants. Produced proteins were confirmed by western blotting, purified by affinity chromotography and finally evaluated for their biological activity. Results: Mutant SK genes were efficiently expressed and due to the fusion of vector-derived His-tag the recombinant full-length and truncated proteins were easily purified. Also despite the replacement of serine to cysteine in the position of 208, the biological activity of the new recombinant protein was still maintained. Conclusion: The produced mutants of this study provide the possibility of establishing the cysteine specific PEGylation process and improvement of clinical activity of streptokinase protein. 586 Others The role of CA1 α-adrenoceptor on scopolamine induced memory impairment in male rats Azami Nasrin-Sadat piri morteza Jahanshahi Mehrdad oryan Shahrbanoo Babapour Vahab zarrindast Mohamad Reza 1 3 2010 14 1 66 77 06 11 2009 15 05 2014 Introduction: Similarities in the memory impairment between Alzheimer patients and scopolamine treated animals have been reported. In the present study, the possible role of α-adrenergic receptors of the dorsal hippocampus on scopolamine state-dependent memory in adult male Wistar rats was evaluated. Methods: The animals were bilaterally implanted with chronic cannulae in the CA1 regions of the dorsal hippocampus, trained in a step-through type inhibitory avoidance task, and tested 24 h after training to measure stepthrough latency. Results: Post-training intra-CA1 administration of scopolamine (0.5 and 2μg/rat) dose-dependently reduced the step-through latency, showing an amnestic response. Amnesia produced by post-training scopolamine (2 μg/rat) was reversed by pre-test administration of the scopolamine (0.5 and 2 μg/rat) that is due to a state-dependent effect. Pre-test intra-CA1 injection of α1-adrenoceptor agonist, phenylephrine (0.25, 0.5 μg/rat) in the dose range that we used, could not affect memory impairment induced by post-training injection of scopolamine (2 μg/rat). However intra-CA1 pretest injection of α2-adrenoceptor agonist, clonidine (0.5 μg/rat) improved post-training scopolamine (2 μg/rat) intra- CA1 injection induced retrieval impairment. Furthermore, pre-test intra-CA1 microinjection of phenylephrine (0.25 and 0.5 μg/rat) or clonidine (0.25 and 0.5 μg/rat) with an ineffective dose of scopolamine (0.25 μg/rat), synergistically improved memory performance impaired by post-training scopolamine (2 μg/rat). Our results also showed that, pre-test injection of α1-receptor antagonist prazosin (1, 2 μg/rat) or α2-receptors antagonist yohimbine (1, 2 μg/rat) before effective dose of scopolamine (2 μg/rat) prevented the improvement of memory by pre-test scopolamine. Conclusion: These results suggest that α1- and α2-adrenergic receptors of the dorsal hippocampal CA1 region may play an important role in scopolamine-induced amnesia and scopolamine state-dependent memory. 595 Pharmacokinetics/Dynamics Antinociceptive and antiinflammatory effects of Teucrium hyrcanicum aqueous extract in male mice and rats Farshchi Amir Ghiasi Golbarg Abdollahuasl Akbar 1 3 2010 14 1 78 84 28 12 2009 15 05 2014 Abstract Introduction: The aim of this study was to investigate the antinociceptive and antiinflammatory effects of Teucrium hyrcanicum aqueous extract in male mice and rats. Methods: To assess the antiinflammatory effect, we used carrageenan- and dextran-induced paw oedema and for determination of the antinociceptive effect, acetic acid-induced writhing, tail flick and formalin pain tests were used. Results: The extract of T. hyrcanicum (50–200 mg/kg) and acetylsalicylic acid (100 mg/kg) produced a significant inhibition of the second phase response in the formalin pain model (P<0.01), while only the high dose of the extract (200 mg/kg) showed an analgesic effect in the first phase. The extract also inhibited acetic acid-induced abdominal writhes in a dose-dependent manner. The tail flick latency was dose dependently enhanced by the extract but this was significantly lower than that produced by morphine 10 mg/kg (P<0.05). The extract (25–250 mg/kg) administered 1 h before carrageenan-induced paw swelling produced a dose dependent inhibition of the oedema. No effect was observed with the dextran-induced oedema model. Conclusion: The obtained data suggest antiinflammatory and analgesic effects for the aqueous extract of Teucrium hyrcanicum, which may be mediated via both peripheral and central mechanisms. The presence of alkaloids, flavonoids and triterpenoids might be responsible for the antiinflammatory activity of this plant. 577 Endocrine Physiology/Pharmacology Effect of the methanolic extract of Daucus carota seeds on the carbohydrate metabolism and morphology of pancreas in type I diabetic male rats Ranjbar Banafsheh Pouraboli Iran Mehrabani Mitra Dabiri Shahriar javadi abdolreza 1 3 2010 14 1 85 93 09 09 2009 15 05 2014 Introduction: Antioxidant agents have beneficial effects in diabetes mellitus. Daucus carota seeds extract has been shown to possess antioxidant activity. In this study, the effect of the methanolic extract of Daucus carota seeds on carbohydrate metabolism and morphology of pancreas was investigated in type I diabetic male rats. Methods: Type I diabetes mellitus was induced in male Wistar rats by injection of 70 mg/kg, i. p. of streptozotocin. Blood samples were collected from the eye cavernousa sinus, before and 5 days after injections for measurement of glucose and insulin. Diabetes was confirmed in rats that had FBS levels above 250 mg/dl. Diabetic rats were divided to 5 groups that received 100, 200 and 300 mg/kg of the extract, glibenclamide (600 μg/kg) and distilled water (0.5 ml) daily for 6 days by gastric gavage. After 6 days, they were sacrificed by decapitation and fasting blood samples were collected and serum levels of glucose and insulin were measured by spectrophotometric and ELISA methods, respectively, by using commercial kits. The pancreas of the rats were dissected out and fixed in 10% formaldehyde for histological studies. Results: Administration of all doses of Daucus carota seeds extract and glibenclamide for 6 days significantly decreased serum glucose levels, however, only 300 mg/kg of the extract as well as glibenclamide significantly increased insulin serum levels. Furthermore the extract and glybenclamide improved pancreas asinuses and islets as the number of islets significantly increased in rats receiving 100 mg/kg of the extract or glibenclamide. Conclusion: D. carota seeds extract has hypoglycemic effect by increasing insulin secretion and improvement of the pancreas.