2024-03-28T19:44:12+03:30 http://ppj.phypha.ir/browse.php?mag_id=8&slc_lang=en&sid=1
8-225 2024-03-28 10.1002
Physiology and Pharmacology Physiol Pharmacol 24765236 24765244 10.61186/phypha 2000 4 1 The effect of estradiol benzoate treatment on the electrical kindled seizures of amygdala in male rats Mehdi Saberi Mohamamd Hossein Pourgholami Masoumeh Jorjani It has been proved that kindling model of amygdala is sensitive to estradiol because the latter accelerates the overall rate of kindling. However the effect of estrogen on the seizure process has not been investigated. In this study fully kindled male rats were treated with different doses (10, 30, and 50 µg/kg, i.p.) of estradiol benzoate (EB) daily and such kindling parameters as seizure stage (SS), after-discharge duration (ADD) and stage 5 duration (S5D) were recorded 15 and 180 min and every 24 h following EB injection for a period of 96 h. While EB at a dose of 10 µg/kg failed to produce a significant effect, but its administration at doses of 30 and 50 µg/kg induced a triphasic effect on seizure parameters. In this regard an initial rapid increment of ADD (after 15 min) was followed by a significant decrease of all parameters after 48 h and then a significant increase in S5D after 96 h was observed. In addition, pretreatment with tamoxifen citrate (TAM) at a dose of 3 mg/kg inhibited the effects of EB (30 µg/kg) for 72 h and pretreatment with TAM at a dose of 10 mg/kg blocked only the inhibitory phase of EB effects after 48 h. Also treatment with the same dose of TAM alone induced a profile similar to EB treatment. These results may suggest that estradiol treatment both increases and decreases kindling parameters in a time- and dose-dependent manner in male rats. These effects probably manifest themselves in genomic and non-genomic forms. Moreover the tamoxifen effects alone could be attributed to its partial agonistic activity on the estrogen receptors. 2000 4 01 3 12 http://ppj.phypha.ir/article-1-225-en.pdf
8-229 2024-03-28 10.1002
Physiology and Pharmacology Physiol Pharmacol 24765236 24765244 10.61186/phypha 2000 4 1 The effect of intraaccumbal injection of L-arginine and L-NAME on induction and removal of conditioned place preference in rat Maryam Nourbakhshnia Ali Haeri Rohani Hoori Sepehri Sirous Jalili Hassan Ghoshouni Hedayat Sahraei Nucleus accumbens (Nac) has been considered as a center for the induction of drug dependence. Since a high concentration of the enzyme, nitric oxide synthase (NOS) has been found in the Nac, and this fact that the role of nitric oxide (NO) in acquisition and expression of drug dependence has become clear in recent years, therefore in this study the effects of intraaccumbal injections of L-arginine (NO precursor) and L-NAME (N-ω-nitro-L-arginine methyl ester) or aminobiguanidine (NOS inhibitor) on induction of conditioned place preference (CPP) in rat were investigated. For this purpose, male Wistar rats (250-300 g) were used. Five days after surgery and cannulation, different doses of L-arginine, L-NAME or aminobiguanidine were injected to animals and conditioning was performed. The results showed that: I) intraaccumbal injection of L-arginine at doses of 0.3, 1 and 3 µg/rat induced CPP. 2) Acute administration of L-NAME (50 mg/kg i.p.) reduces the effect of L-arginine and chronic administration of the drug (10, 50, and 200 mg/kg i.p.) has no effect. 3) intraaccumbal injection of both L-NAME and aminobiguanidine (0.3, 1, and 3 µg/rat) produces no effect. In conclusion, it seems likely that intraaccumbal injection of L-arginine could induce CPP and part of its effect might be due to the release of NO from L-arginine. L-arginine; Aminobiguanidine; L-NAME; CPP; Rat 2000 4 01 13 19 http://ppj.phypha.ir/article-1-229-en.pdf
8-232 2024-03-28 10.1002
Physiology and Pharmacology Physiol Pharmacol 24765236 24765244 10.61186/phypha 2000 4 1 Chemical kindling enhances the Schaffer collateral-CAl pyramidal cell synaptic transmission in anesthetized rats Mohamamd Reza Palizvan Yaghoub Fathollahi Epilepsy is one of the common disorders in human community. Clinical observations have shown that epileptic patients have often difficulty in learning and memory. Kindling is a laboratory model for studying epilepsy and its complications. This experiment was designed to study the effect of chemical kindling on Schaffer collateral-CA1 pyramidal cell synaptic transmission using pentylenetetrazole in urethane-anesthetized rats. Experiments were carried out on the hippocampal CA1 region from control and kindled rats at two periods post-kindling, i.e. 48-144 h (early phase) and 30-33 day (long-lasting phase). Population spike (PS) was recorded at stratum pyramidale following stimulation of the stratum fibers. The results showed that 48-144 h after kindling, the slope of population excitatory post-synaptic potential (pEPSP), the PS amplitude and spike latency in CA1 region of kindled rats were not significantly different than that of control. In contrast, 30 to 33 days after kindling, the amplitude of PS was significantly greater than that of control (p<0.01). These results suggest that chemical kindling entails long lasting changes in the function of CA1 that appear as enhanced excitability after one month Seizure; Hippocampus; Population spike; Rat 2000 4 01 21 28 http://ppj.phypha.ir/article-1-232-en.pdf
8-228 2024-03-28 10.1002
Physiology and Pharmacology Physiol Pharmacol 24765236 24765244 10.61186/phypha 2000 4 1 The effect of adenosine and caffeine on paragigantocellularis (PGi) nucleus neurons in morphine-dependent rats Mohsen Khalili Saeed Semnanian Yaghoub Fathollahi In this study the effect of adenosine and caffeine on spontaneous activity of paragigantocellularis (PGi) neurons was investigated. The spontaneous activity of PGi neurons was significantly decreased by microinjection of adenosine (10 nM, 0.5 µl) into PGi nucleus of both control and morphine-dependent rats. The decrease in firing rate of PGi neurons of morphine-dependent rats was greater than that of control. There was also significant enhancement of spontaneous activity of PGi neurons 8-15 min after caffeine administration (50 mg/kg i.p.) in both control and morphine-dependent rats. However, the effect of caffeine in morphine-dependent rats was higher than that of control. These data suggest that there is an increase in the sensitivity to chemicals, which interact with adenosine receptors in morphine- dependent rats. Nevertheless, considering a common second messenger system (cAMP) for adenosine (A1) and opioid (µ) receptor, it is proposed that up-regulation and hypersensitivity of A1 adenosine receptors are responsible for these results in morphine-dependent rats. Morphine; Tolerance; Dependence; Nucleus paragigantocellularis; Single unit recording; Adenosine receptors; Caffeine 2000 4 01 29 38 http://ppj.phypha.ir/article-1-228-en.pdf
8-235 2024-03-28 10.1002
Physiology and Pharmacology Physiol Pharmacol 24765236 24765244 10.61186/phypha 2000 4 1 The role of histamine receptors in restraint stress-induced immunosuppression in the rat brain Taghi Ghafghazi Fatemeh Zeraati Minoo Adib Abbas Rezaei Restraint-induced stress (RS) increases histamine concentration in the brain. There is no previous report regarding the role of histamine receptors in immunomodulatory effect of RS. In the present study the role of brain histamine receptors on reduction of humoral and cellular immune function induced by RS was evaluated. For this purpose male Wistar rats (200-250 g) were immunized with sheep red blood cells (SRBCs). The results showed that RS reduced the humoral and cell-mediated immunity in immunized rats (p<0.01). Similarly, ICV injection of histamine (150 µg/rat) without stress reduced significantly humoral and cellular immune function (p<0.01). Pretreatment with chlorpheniramine (50 µg/rat) reduced the inhibitory effect of RS. In addition, histamine (150 µg/rat) could inhibit the effect of chlorpheniramine if injected simultaneously. Ranitidine (10 µg/rat) had no significant effect. ICV injection of lower doses of R-α-methyl histamine reduced the effect of RS on immune function, but the effect of RS on immunity increased at higher doses (10 µg/rat) of the drug. These results indicated that histamine has a central role in RS-induced immunosuppression through brain's H1 receptors. Furthermore H3 histamine receptors induce a dose-dependent bi-directional effect, which may be due to the role of this receptor in non- histaminic nervous system. Restraint stress; Histamine; Immune system; Central histamine receptors 2000 4 01 39 48 http://ppj.phypha.ir/article-1-235-en.pdf
8-236 2024-03-28 10.1002
Physiology and Pharmacology Physiol Pharmacol 24765236 24765244 10.61186/phypha 2000 4 1 The role of GABAB receptors in imipramine-induced antinociception in experimental model of neuropathic pain Sadegh Valizadeh Mohammad Reza Zarrindast This study was designed to investigate the role of GABAB receptor agents on imipramine-induced antinociception in ligated and non-ligated mice using hot-plate test. The data showed that different doses of morphine (3, 6, and 9 mg/kg) induced a dose-dependent antinociception in ligated and non-ligated mice. However, the opioid response was decreased in ligated animals. Intracerebroventricular (i.c.v.) administration of imipramine (5, 10, 20, and 40 µg/mouse) did not induce antinociception in either non-ligated or ligated mice. However, the induced response in the ligated mice was less than that induced in the non-ligated mice. Intraperitoneal (i.p.) administration of imipramine (10, 20, 30, and 40 mg/kg) induced antinociception in both ligated and non-ligated mice. The responses to the drug were not significantly different in the two groups. Administration of baclofen either i.c.v. (0.125, 0.25, and 0.5 µg/mouse) or i.p. (0.5, 1,2, and 4 mg/kg) induced antinociception. The response to the drug was not significantly different in ligated and non-ligated mice. Intracerebroventricular administration of a lower dose of baclofen (0.125 µg/mouse) with different doses of imipramine (2.5, 5, and 10 mg/kg) potentiated the response to imipramine. This effect was reduced by i.c.v. injection of GABAB receptor antagonist, CGP35348 [P-(3-aminopropyl)-p-diethoxymethyl- phosphinic acid] at a dose of 20 µg/mouse. The higher dose of antagonist (20 µg /mouse) also decreased the response induced by baclofen or imipramine. CGP35348 itself (2.5, 5, 10, and 20 µg/mouse) induced a dose-dependent antinociception with no significant difference in the ligated and non-ligated mice. It is concluded that a GABA receptor mechanism(s) may modulate the antidepressant-induced antinociception. Imipramine; Baclofen; CGP35348; Ligation; Neuropathic pain; Hot-plate test 2000 4 01 85 94 http://ppj.phypha.ir/article-1-236-en.pdf
8-224 2024-03-28 10.1002
Physiology and Pharmacology Physiol Pharmacol 24765236 24765244 10.61186/phypha 2000 4 1 The effect of local injection of amitriptyline on the formalin test model of pain Esmaeil Akbari Fereshteh Motamedi Mohamamd Reza Vaez-Mahdavi Amitriptyline, a tricyclic antidepressant agent is used as one of the analgesic drugs in different kinds of pain. In the present study the effect of local (subcutaneous) injection of amitriptyline (50 and 100 µg) on the acute and chronic pain using formalin test, was investigated. Our data show that local injection of amitriptyline to the paw receiving formalin, causes a decrease in pain in both phasic and tonic phases of formalin test. On the other hand, in the group that this drug was injected (100 µg) to the contralateral paw, no significant change was observed in the pain score with respect to the control group. Therefore, it seems that the observed effect is due to the local action of amitriptyline and not as a result of its systemic effect. Considering the above-mentioned results, it is concluded that: 1) Amitriptyline acts like a local anesthetic in both acute and tonic phases of formalin test. 2) The mechanism of analgesia in the acute phase is probably caused by sodium channel blockade. 3) The analgesic effect of amitriptyline in the tonic phase of formalin test might be due to its antihistaminic and anti-inflammatory effects at the peripheral level, and also is due to the changes in the CNS plasticity which occurs during the acute phase. Amitriptyline; Formalin test; Local Anesthesia; Analgesia; Pain 2000 4 01 95 102 http://ppj.phypha.ir/article-1-224-en.pdf