@article{ author = {Salami, Mahmood and Fathollahi, Yagoob}, title = {Involvement of voltage-dependent calcium channels in synaptic plasticity of the rat visual cortex}, abstract ={In this study, involvement ofvoltage-dependent calcium channels in LTP of responses of rat visual cortex slices was analyzed. Field potentials including EPSP1 and EPSP2 from layers II/III were recorded through stimulation of layer IV. Whereas nifedipine, a L-type calcium channel blocker (L-VDCC), did not considerably affect the LTP of responses, but Ni2+, a relatively selective blocker of T-type calcium channels (T-VDCC) decreased potentiation of EPSP1 and partly blocked that of EPSP2. The effect of visual experience on the function of channels was also evaluated. The results showed that T-VDCCs mediate a transient augmentation of EPSP1, while contribute to a stable LTP of EPSP2. Whereas sensory experience influences the occurrence of LTP in field potentials, it seems to be ineffective on the role of calcium channels in synaptic plasticity. It is concluded that the T-VDCCs alone by allowing calcium influx into neurons or by sharing NMDA receptors are involved in the synaptic plasticity.}, Keywords = {Calcium channels; LTP; Synaptic plasticity; Visual cortex}, volume = {6}, Number = {1}, pages = {0-0}, publisher = {Iranian Society of Physiology and Pharmacology}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ppj.phypha.ir/article-1-401-en.html}, eprint = {}, journal = {Physiology and Pharmacology}, issn = {24765236}, eissn = {24765244}, year = {2002} } @article{ author = {Hajhashemi, Valiolah and Ghafghazi, Taghi and Nikravan, Mohammad Rez}, title = {Effect of dextromethorphan, amantadine, and ketamine on morphine withdrawal syndrome in mice}, abstract ={Recent studies have shown that NMDA receptors are involved in the tolerance and dependence to opioids. In addition, it has been reported that ketamine, dextromethorphan and amantadine have antagonistic activity at NMDA receptors. Therefore, this study was conducted to clarify the effect of these drugs on morphine withdrawal syndrome. Morphine dependence was induced by increasing doses of morphine (30, 45, 60, and 90 mg/kg, s.c.) administered at 2 h intervals. Dextromethorphan (12.5, 25, and 50 mg/kg), amantadine (50, 100, and 150 mg/kg), ketamine (50 mg/kg), and clonidine (0.2 mg/kg) were injected (i.p.) 90 minutes after the last injection of morphine. Furthermore, these drugs were administered orally 60 minutes after the last morphine injection. All animals received naloxone (5 mg/kg, i.p.) 2 h after the last morphine injection. Withdrawal syndrome (number of jumping, standing on feet. and diarrhea) was recorded during a 30-min period. Dextromethorphan and amantadine inhibited jumping, standing on feet and diarrhea in a dose-dependent manner. Ketamine (50 mg/kg) had a similar effect and clonidine produced an almost complete inhibition of withdrawal syndrome. Although these test drugs belong to different pharmacological classes, but they share NMDA receptor antagonistic effect and it may be the probable cause for inhibition of withdrawal syndrome.}, Keywords = {Dextromethorphan; Amantadine; Ketamine; Clonidine; Morphine; Withdrawal syndrome}, volume = {6}, Number = {1}, pages = {3-9}, publisher = {Iranian Society of Physiology and Pharmacology}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ppj.phypha.ir/article-1-390-en.html}, eprint = {}, journal = {Physiology and Pharmacology}, issn = {24765236}, eissn = {24765244}, year = {2002} } @article{ author = {Motamedi, Fereshteh and Danyali, Samira and VaezMahdavi, Mohammad Rez}, title = {A comparative study on pain sensation in morphine-dependent male and female rats in the presence and absence of gonads using formalin test}, abstract ={Various physiological parameters including level of sex steroids undergo alterations following chronic administration of morphine. In this study, the effect of chronic administration of morphine on phasic and tonic pain was studied in morphine-dependent male and female rats in the presence and absence of gonads using formalin test. In addition, for evaluation of differences in dependency, withdrawal signs were observed using naloxone hydrochloride. For dependency induction, morphine sulphate was administered in drinking water for a period of 30 days. The results showed that although chronic pain is significantly greater in female rats than male ones but this pain increases in male dependent rats and decreases in female dependent animals. Thus, no gender differences were found between male and female dependent rats. Furthermore, gonadectomy led to a significant decrease in chronic pain only in male dependent rats. Meanwhile, withdrawal signs were significantly greater in female dependent rats than male ones and gonadectomy did not influence these signs. It can be concluded that following morphine addiction, pain increases in male and decreases in female rats and morphine dependency is not affected by sex hormones.}, Keywords = {Sex difference; Pain; Morphine dependency; Formalin test; Rat}, volume = {6}, Number = {1}, pages = {11-19}, publisher = {Iranian Society of Physiology and Pharmacology}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ppj.phypha.ir/article-1-391-en.html}, eprint = {}, journal = {Physiology and Pharmacology}, issn = {24765236}, eissn = {24765244}, year = {2002} } @article{ author = {}, title = {Effect of reversible inactivation of locus ceruleus on naloxone-induced withdrawal syndrome in paragigantocellular neurons in morphine-dependent rats}, abstract ={In this study, the effect of reversible inactivation of locus ceruleus (LC) on naloxone- induced withdrawal syndrome in paragigantocellular (PGi) neurons in morphine- dependent rats was investigated. For inactivation of LC, 1 µl of lidocaine (2%) was used and for induction of withdrawal syndrome, naloxone hydrochloride (2 mg/kg) was injected systemically. The results showed that in dependent group with intact LC, PGi single unit activity increased following naloxone administration, whereas in dependent group with inactivated LC, the observed increase was not significant.}, Keywords = {Paragigantocellular nucleus; Locus ceruleus; Morphine dependence; Withdrawal syndrome; Functional inactivation}, volume = {6}, Number = {1}, pages = {21-26}, publisher = {Iranian Society of Physiology and Pharmacology}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ppj.phypha.ir/article-1-392-en.html}, eprint = {}, journal = {Physiology and Pharmacology}, issn = {24765236}, eissn = {24765244}, year = {2002} } @article{ author = {Behzadi, Jila and Sheibani, Vahid and Esteky, Hossein and Ganji, Farzaneh}, title = {Effect of locus ceruleus phasic electrical stimulation on responses of barrel cortical cells to controlled mechanical displacement in rats}, abstract ={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.}, Keywords = {Locus ceruleus; Barrel cortex; Sensory processing; Phasic electrical stimulation}, volume = {6}, Number = {1}, pages = {27-37}, publisher = {Iranian Society of Physiology and Pharmacology}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ppj.phypha.ir/article-1-393-en.html}, eprint = {}, journal = {Physiology and Pharmacology}, issn = {24765236}, eissn = {24765244}, year = {2002} } @article{ author = {Semnanian, and GhaderiPakdel, and Fathollahi, and Firoozabadi,}, title = {A new method for acquisition and analysis of single unit recording data}, abstract ={Single unit recording has been used as a well-known technique to study the electrical behavior of neurons. In this respect, the classical methods are rather expensive. In this study a simple and inexpensive method for single unit recording studies has been introduced. Computer sound card was used for data acquisition. Neural responses were saved via simple sound applicable packages and then analyzed for peristimulus time histogram (PSTH) extraction by home-made software. Analog to digital (AID) converter board and sound card simultaneously recorded neuronal activities in two brainstem nuclei (paragigantocellularis lateralis (PGi) and locus ceruleus (LC)). Then, PSTH of data were calculated online for AID captured data and offline for sound card captured data. The results showed that there were no significant differences between PSTH of PGi or LC neurons in two protocols. Therefore, sound cards can be used as well as AID boards for data acquisition in electrophysiological laboratories}, Keywords = {Single unit recording; Peristimulus time histogram; AID board; PC sound card; Paragigantocellularis lateralis; Locus ceruleus; Successive-approximation chip; Sigma-Delta chip}, volume = {6}, Number = {1}, pages = {39-53}, publisher = {Iranian Society of Physiology and Pharmacology}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ppj.phypha.ir/article-1-394-en.html}, eprint = {}, journal = {Physiology and Pharmacology}, issn = {24765236}, eissn = {24765244}, year = {2002} } @article{ author = {}, title = {A new method for acquisition and analysis of single unit recording data}, abstract ={Single unit recording has been used as a well-known technique to study the electrical behavior of neurons. In this respect, the classical methods are rather expensive. In this study a simple and inexpensive method for single unit recording studies has been introduced. Computer sound card was used for data acquisition. Neural responses were saved via simple sound applicable packages and then analyzed for peristimulus time histogram (PSTH) extraction by home-made software. Analog to digital (AID) converter board and sound card simultaneously recorded neuronal activities in two brainstem nuclei (paragigantocellularis lateralis (PGi) and locus ceruleus (LC)). Then, PSTH of data were calculated online for AID captured data and offline for sound card captured data. The results showed that there were no significant differences between PSTH of PGi or LC neurons in two protocols. Therefore, sound cards can be used as well as AID boards for data acquisition in electrophysiological laboratories.}, Keywords = {Single unit recording; Peristimulus time histogram; AID board; PC sound card; Paragigantocellularis lateralis; Locus ceruleus; Successive-approximation chip; Sigma-Delta chip}, volume = {6}, Number = {1}, pages = {39-53}, publisher = {Iranian Society of Physiology and Pharmacology}, title_fa = {روش جدید برای دریافت و تجزیه و تحلیل فعالیت الکتریکی سلول‌های عصبی}, abstract_fa ={}, keywords_fa = {}, url = {http://ppj.phypha.ir/article-1-142-en.html}, eprint = {}, journal = {Physiology and Pharmacology}, issn = {24765236}, eissn = {24765244}, year = {2002} } @article{ author = {Nabavizadeh, Fatemeh and ZahediAsl, Saleh and GharibNaseri, Mohammad Kazem}, title = {Effect of thyroid hormones on basal and stimulated gastric acid secretion due to histamine, carbachol, and pentagastrin in rat (an in vitro study)}, abstract ={Although thyroid hormones are known to influence acid secretion, but exact mechanisms are not fully understood. So, in this experimental study carbachol, histamine, and pentagastrin were used to stimulate acid secretion in isolated stomach of hypo- and hyperthyroid rats and data were compared with controls. Each group consisted of 8 N-Mari rats from both sexes weighing 246 ± 5 g. Hypo- and hyperthyroid states were induced by administration of methimazole (500 mg/l) thyroxine (500 µg/l) in drinking water respectively. All animals were deprived of food 24 h before the experiments, but they accessed to water ad libitum. After general anesthesia with sodium thiopental (50 mg/kg of body weight, i.p.), celiotomy was done immediately. The end of esophagus was tied and a silicon tube (2-2.5 mm) was entered the stomach via a hole in the second portion of the duodenum. Then, it was tied in the pyloric region. After these procedures, the esophagus was cut proximal to the tied portion and the second part of duodenum was also cut. Then, the stomach was removed and put in a cold serous solution. After washing the serosal and mucosal surfaces by serous and mucosal solutions respectively, the stomach was transferred to a tissue bath containing warm serous solution (40 ml, 37 °C). Acid secretion following carbachol, histamine, and pentagastrin administration was measured by washout technique and automatic titrator in the hypo- and hyperthyroid and control groups. Furthermore, some dose-response experiments with different doses of pentagastrin (30, 60, 90, and 120 µg/kg), histamine (50, 100, 150, and 200 µM), and carbachol (50, l00, and 200 µM) were performed to clarify the mechanism of thyroid hormones effect on acid secretion. The results showed that basal and histamine (100 µM)-stimulated secretion in hypo and hyperthyroid groups significantly decreased and increased respectively compared to control ones (p<0.0001). Basal and carbachol (100 µM)-stimulated acid secretion significantly decreased in hypothyroid group, while the secretion showed a significant increase in hyperthyroid group compared to control group (p<0.0001). The results of TSH and T4 measurement showed that increased or decreased thyroid function can significantly affect gastric acid secretion following histamine, carbachol, and pentagastrin in rats. Taken together, it can be concluded that effects of thyroid hormones may not be mediated through changing cholinergic, gastrin, and histamine receptors. It is also possible that thyroid hormones exert their effects on the number or size of the secretory cells of the stomach.}, Keywords = {Thyroid hormones; Acid secretion; Histamine; Carbachol; Pentagastrin; Rat}, volume = {6}, Number = {1}, pages = {55-66}, publisher = {Iranian Society of Physiology and Pharmacology}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ppj.phypha.ir/article-1-395-en.html}, eprint = {}, journal = {Physiology and Pharmacology}, issn = {24765236}, eissn = {24765244}, year = {2002} } @article{ author = {Elyasi, Afsaneh and Noureddini, Mahdi}, title = {Effect of D-glucose injection into ventromedial and lateral nuclei of hypothalamus on pentagastrin-induced gastric secretion in rat}, abstract ={It has been shown that those factors which affect gastric acid secretion through the ventromedial and lateral nuclei of hypothalamus, can significantly alter centrally-mediated secretion. There is much evidence that glucose is among these factors that through a central mechanism can decrease induced acid secretion. It appears that this effect is mediated through glucose-sensitive neurons within lateral (LH) and ventromedial (VMH) nuclei of hypothalamus. Therefore, this study was carried out to evaluate the effect of D-glucose injection into LH and VMH on pentagastrin-induced hyperacidity in anesthetized rats. After induction of anesthesia, guide cannula was stereotaxically inserted 1 mm above VMH and/or LH of both sides. Then, after 3-7 days the stomach was washed out, and from 15 min on, sampling (every 5 min) from gastric secretion was done until the end of experiment. Venous infusion of pentagastrin (2 µg/100 g/h) increased acid secretion and it reached to its maximum level after 30 min. The results showed that D-glucose injection (10, 20, 30, and 90 mM) at a rate of 1 µl/rat significantly and in a dose-dependent manner reduce acid secretion, while L-glucose injection (30 mM) or saline solution (154, 169, and 200 mM) did not significantly affect acid secretion. It can be concluded that the VMH and LH contain glucose-sensitive neurons that can influence gastric acid secretion, and D-glucose can be effective on these neurons, which through this way can reduce peripherally-induced hyperacidity. In addition, this effect is stronger at LH than VMH, and the other analogue of glucose (L-glucose) can not affect this phenomenon.}, Keywords = {Lateral and Ventromedial nuclei of hypothalamus; Hyperacidity; Gastrin; D-glucose}, volume = {6}, Number = {1}, pages = {67-78}, publisher = {Iranian Society of Physiology and Pharmacology}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ppj.phypha.ir/article-1-396-en.html}, eprint = {}, journal = {Physiology and Pharmacology}, issn = {24765236}, eissn = {24765244}, year = {2002} } @article{ author = {Sadr, Shahabedin and Dehpour, Ahmad Reza and Yousofvand, Namdar and Shadan, Farokh and Norouzi, Abbas}, title = {Effect of ouabain on submandibular salivary gland and level of zinc and copper in saliva and serum in rat}, abstract ={In this study, the effect of various doses of ouabain (1, 2, and 5 mg/kg, i.p.) on weight and flow rate of submandibular gland (SMG) and changes in zinc and copper levels in pure saliva and serum of rats was investigated. The time interval between injection of drug and sampling was 30 min. In addition, the effect of a single and toxic dose of ouabain (5 mg/kg, i.p.) in various time intervals (30 min, 1, 2, 3, 7, and 14 days) was also studied. The results showed that in all groups, normalized weight of SMG did not differ significantly. Meanwhile, flow rate decreased 30 min after injection in those animals receiving 2 and 5 mg/kg ouabain and one day after injection in the group receiving 5 mg/kg ouabain. After this time period, all flow rates recovered. In addition, level of zinc increased in serum and saliva in those groups receiving 2 and 5 mg/kg ouabain after 30 min, but it decreased in the group receiving 1 mg/kg of the drug and in recovered groups after 2, 3, and 7 days, serum zinc concentration showed a negligible elevation. Further analysis of data showed that there was no correlation between serum and salivary copper levels. In this respect, only salivary copper level decreased in groups receiving 1, 2, and 5 mg/kg of ouabain and in recovered group after 1 day, whereas copper level only decreased in serum in groups receiving ouabain after 2, 3, and 7 days. Therefore, alterations in zinc level correlate with the inhibitory effects of ouabain on sodium-potassium pump, which may also be the mechanism responsible for the uptake or transport of zinc in this gland. It is noteworthy that alterations in zinc and copper level were opposite of each other in saliva of groups receiving 2 and 5 mg/kg of ouabain and in recovery groups and also in the serum obtained from recovery groups. Taken together, it seems that a period of 14 days is enough for recovery from all of the changes due to the toxic doses of ouabain.}, Keywords = {Submandibular gland; Serum; Ouabain; Zinc; Copper; Rat}, volume = {6}, Number = {1}, pages = {79-85}, publisher = {Iranian Society of Physiology and Pharmacology}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ppj.phypha.ir/article-1-397-en.html}, eprint = {}, journal = {Physiology and Pharmacology}, issn = {24765236}, eissn = {24765244}, year = {2002} } @article{ author = {Firoozabadi, Seyed Mohammad and Torkaman, Giti and Ebrahimi, Fatemeh}, title = {A comparative study on soleus H reflex parameters using vertebral column and peripheral nerve stimulation}, abstract ={Although low-threshold transcutaneous electrical nerve stimulation (TENS) is a modality used for control of pain, but its effect in the control of spasticity and change of excitability of a motor neuron is controversial. Therefore, this study was conducted to evaluate the effects of 15-min tripolar TENS of vertebral column and bipolar TENS of common peroneal nerve (300 µs width, 50 Hz) on synaptic activities of spinal cord. For this purpose, soleus H-reflex, Mh wave (M wave on the H-reflex signal) and M wave parameters were studied. Twelve healthy and non-athletic female volunteers were tested in two groups. First group received vertebral column stimulation and second group received peripheral stimulation in 4 separate experimental sessions (two control and two test sessions). In the first group, tripolar TENS (cathode on T 11, one anode 3 cm above and the other 7 cm below the cathode) was applied. In the second group, bipolar TENS (cathode on common peroneal nerve at the level of fibular head and anode 3 cm below the cathode) was used. Then, the acquired data were analyzed statistically. The results showed that peak to peak amplitude (PP), area under the curve and average rectified value (ARV) of H-reflex in the first stimulation group decreases (p<0.05), but in the second group, there is no significant changes. In addition, these parameters increased for Mh wave in the first group, but in the second group, there were no significant changes. It is suggested that tripolar TENS of vertebral column has augmented activity of the fast motor units. In this respect, it is possible that Renshaw cells are more activated and suppressed the activity of the slow motor units. These effects tended to increase the sensitivity of soleus motor end plate and decrease H-reflex amplitude. It can be concluded that tripolar TENS of vertebral column (depending on the site and method of stimulation) appears to be effective in synaptic activities of the spinal cord, especially the fast motor units and Renshaw cells, while bipolar TENS of common peroneal nerve does not produce such effect.}, Keywords = {Tripolar electrical stimulation; Bipolar electrical stimulation; TENS; H-reflex; Renshaw cell; Mh wave}, volume = {6}, Number = {1}, pages = {91-98}, publisher = {Iranian Society of Physiology and Pharmacology}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ppj.phypha.ir/article-1-398-en.html}, eprint = {}, journal = {Physiology and Pharmacology}, issn = {24765236}, eissn = {24765244}, year = {2002} } @article{ author = {Abbasnejad, Mehdi and Karimian, Morteza and Zarrindast, Mohammad Reza and Faghihi, Mahdiye and Bahrampour, Abbas}, title = {Effect of sulpiride injection into ventromedial nucleus of hypothalamus on food and water intake and weight in male rats}, abstract ={Weight gain, obesity and hyperprolactinemia are important complications of long-term administration of neuroleptic drugs, which may affect the patient's general health and well- being that itself interferes with treatment compliance. The purpose of this study was to identify the mechanism of occurrence of these side-effects. Because of the important role of ventromedial nucleus of hypothalamus (VMN) in the regulation of food intake, effect of sulpiride, a D2 antagonist on food intake was evaluated. For this purpose, 28 adult male rats weighing 280-320 g were used. Cannulae were implanted bilaterally in the VMN. After recovery period, rats were divided into 4 groups and 3 out of them received different doses of sulpiride (4, 8, and 16 µg/0.5 µl). Sham-operated group received daily injection of the vehicle of sulpiride (HCl 0.1 N) through the cannula for seven consecutive days. Food and water intake was measured daily for 7 days and then, mean food and water intake for 24 h was calculated. The results showed that sulpiride increases food and water intake at all doses, but body weight only increases at doses of 8 and 16 µg. It can be concluded that blockade of D2 dopamine receptors in VMN is involved in hyperphagic and dipsogenic effect of neuroleptic drugs, even in rats with no food restriction.}, Keywords = {Sulpiride; Ventromedial nucleus of hypothalamus; Feeding; D2 receptor; Water intake}, volume = {6}, Number = {1}, pages = {99-105}, publisher = {Iranian Society of Physiology and Pharmacology}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ppj.phypha.ir/article-1-399-en.html}, eprint = {}, journal = {Physiology and Pharmacology}, issn = {24765236}, eissn = {24765244}, year = {2002} } @article{ author = {Heidari, Mohammad Reza and Asadipour, Ali and Hami, Mahdi}, title = {Analgesic and ulcerogenic effect of methanolic extract of Artemisia dracunculus and histopathological evaluation}, abstract ={In this study, the analgesic effect of Artemisia dracunculus, which has been used in traditional medicine as an analgesic, anti-rheumatic and toothache releiver was studied. For extraction, suxhelet and percolation methods by 80% methanol was used. The extract was then concentrated and the weight of dried extract was determined and dissolved in normal saline to produce desired concentration. The analgesic effect of the extract was determined by the formalin and hot-plate tests. The results of formalin test showed that all doses of the extract have analgesic effect in comparison with control group and the extract at a dose of 800 mg/kg produces the highest analgesic effect. In this respect, there was no significant difference regarding the extracting methods. The results of hot plate showed that the extract at a dose of 800 mg/kg has a significant analgesic effect compared to control group. In addition, the analgesic effect of extract was compared with ASA and morphine by formalin and hot plate tests. The results showed that the analgesic effect of 800 mg/kg of extract was higher than ASA and lower than morphine in some trials. Furthermore, pretreatment of animals with naloxone decreased the analgesic effect of extract. Therefore, it seems that part of analgesic effect of the extract may be attributed to opioid system. At the end of the study, those rats receiving 800 and 1600 mg/kg of the extract and control ones were collected for histopathological evaluation. The results showed that there is only small congestion in liver and kidney after the extract injection. In addition, there was no sign of peptic ulcer in comparison with rats receiving indomethacin.}, Keywords = {Medicinal plants; Artemisia dracunculus; Pain assessment; Hot plate; Formalin test; Ulcerogenicity; Histopathology}, volume = {6}, Number = {1}, pages = {107-118}, publisher = {Iranian Society of Physiology and Pharmacology}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ppj.phypha.ir/article-1-400-en.html}, eprint = {}, journal = {Physiology and Pharmacology}, issn = {24765236}, eissn = {24765244}, year = {2002} } @article{ author = {}, title = {Involvement of voltage-dependent calcium channels in synaptic plasticity of the rat visual cortex}, abstract ={In this study, involvement ofvoltage-dependent calcium channels in LTP of responses of rat visual cortex slices was analyzed. Field potentials including EPSP1 and EPSP2 from layers II/III were recorded through stimulation of layer IV. Whereas nifedipine, a L-type calcium channel blocker (L-VDCC), did not considerably affect the LTP of responses, but Ni2+, a relatively selective blocker of T-type calcium channels (T-VDCC) decreased potentiation of EPSP1 and partly blocked that of EPSP2. The effect of visual experience on the function of channels was also evaluated. The results showed that T-VDCCs mediate a transient augmentation of EPSP1, while contribute to a stable LTP of EPSP2. Whereas sensory experience influences the occurrence of LTP in field potentials, it seems to be ineffective on the role of calcium channels in synaptic plasticity. It is concluded that the T-VDCCs alone by allowing calcium influx into neurons or by sharing NMDA receptors are involved in the synaptic plasticity.}, Keywords = {Calcium channels; LTP; Synaptic plasticity; Visual cortex}, volume = {6}, Number = {1}, pages = {119-128}, publisher = {Iranian Society of Physiology and Pharmacology}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ppj.phypha.ir/article-1-402-en.html}, eprint = {}, journal = {Physiology and Pharmacology}, issn = {24765236}, eissn = {24765244}, year = {2002} }