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Showing 3 results for Zeraati

Taghi Ghafghazi, Fatemeh Zeraati, Minoo Adib, Abbas Rezaei,
Volume 4, Issue 1 (Spring and Summer 2000)
Abstract

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.
Maryam Zeraati, Javad Mirnajafi-Zadeh, Mohammad Javan, Saeed Semnanian, Simin Namvar,
Volume 14, Issue 2 (Summer 2010)
Abstract

Introduction: Considering high prevalence of epileptic disease and considering that 40 percent of epileptic patients are resistant to drug therapy, it needs more researches to find new therapeutic ways. LFS is among the new methods for epilepsy treatments. One possible mechanism involved in the anticonvulsant effect of LFS is increased adenosine. Therefore, in this study the role of adenosine production from ATP by ectonucleotidase enzyme pathway in exerting the anticonvulsant effects of LFS were evaluated. Methods: Animals were kindled by electrical stimulation of perforant path in a rapid kindling manner (12 stimulation per day). One group of animals received LFS after kindling stimulation. In one another group, AOPCP a blocker of ectonucleotidase inhibitor was micro injected (50 micro molar) intra cerebro ventricular each day before LFS stimulation. Some group of animals were also received AOPCP (50 and 100 micro molar) but were not applied to LFS. Seizure behavior and electrophysiological parameters (including ADD and field potential) were recorded. Results: Like previous investigations, application of LFS, decreased all seizure parameters significantly. Microinjection of AOPCP had no significant effect on anticonvulsant actions of LFS. However microinjection of AOPCP at doses of 100 micro molar in animals that received just kindling stimulations, increased the seizure parameters significantly. Conclusion: The results show that adenosine production via ectonucleotidase enzyme pathway may has no role in anticonvulsant effects of LFS however endogenous adenosine produced through this pathway has an important role in kindling development.
Simin Namvar, Javad Mirnajafi-Zadeh, Mohammad Javan, Maryam Zeraati,
Volume 14, Issue 3 (Fall 2010)
Abstract

Introduction: Application of low-frequency stimulation (LFS) is a new method for treatment of drug resistant epileptic patients. Previous studies demonstrated that activation of receptors coupled to Gi proteins is one of the mechanisms of the anticonvulsant effect of LFS. Thus, in this study, alterations in the expression of RGS4 and RGS10 proteins, as negative regulators of Gi proteins, were investigated. Methods: Animals were kindled by perforant path stimulation in a rapid kindling manner (12 stimulation per day, 1 ms pulse duration at 50 Hz). LFS (8 stimulation per day, 0.1 ms pulse duration at 1 Hz, 200 pulses) was applied to the perforant path 5 minute after the termination of kindling stimulations. After electrophysiological recordings for 6 days, the dentate gyrus of the animals was removed and RGS4 and RGS10 protein expression was studied by western blotting technique. Results: Application of LFS significantly retarded kindling acquisition and increased the number of stimulations to achieve different stages of seizure. LFS also significantly reduced after discharge duration. In addition, application of LFS after kindling stimulation reduced the expression of RGS4 and RGS10 proteins. Conclusion: Results of the present study showed that LFS has anticonvulsant effects on the perforant path kindling. Application of LFS following kindling stimulation reduced the expression of RGS4 and RGS10 proteins. Reduction of the expression of these proteins results in the longer activation of signaling pathways of Gi proteins, which may be responsible for LFS anticonvulsant effects.

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