[In vitro anti-toxoplasma effects of ethanolic extracts of Artemisia absinthium L., Carum copticum L. and Gossypium Hirsutum]

Background: Production of anti-Toxoplasma drug with high efficacy and low side effect is one of the main priorities in toxoplasmosis researches. Herbal extracts has considered as a candidate for this purpose

Objective: This study was performed in order to determine lethal effect of Artemisia absinthium L., Carum copticum L. and Gossypium hirsutum extracts on Toxoplasma gondii tachyzoites in vitro free cell line

Methods: Tachyzoites of T. gondii RH strain were treated with concentrations of 10, 50, 100, and 200 mg/ml of Artemisia absinthium L., Carum copticum L., and Gossypium hirsutum extracts within 10, 30, and 45 min. Afterward, the tachyzoites were stained with alkaline methylene blue. Mortality rates of tachyzoites treated with extracts were determined. The results were analyzed with one way ANOVA and Post Hoc Test by SPSS software. P<0.05 was considered to be statistically significant

Results: The overall, 100% of tachyzoites were killed at concentrations of 50, 100, and 200 mg/ml of Artemisia absinthium L. and 200 mg/ml of Carum copticum L. after 10, 30, and 45 min treatment. The lowest mortality rates at concentration of 10 mg/ml were 19.6 +/- 8.4, 4.30 +/- 2.26, and 4.63 +/- 2.1 for Artemisia absinthium L., Carum copticum L., and Gossypium hirsutum, respectively. The highest and lowest mortality rate of tachyzoites by Gossypium hirsutumin extract was 13.3 +/- 7.1. The mortality of tachyzoites were confirmed by bioassay in mice

Conclusion: Anti-Toxoplasma activities of Artemisia absinthium L. and Carum copticum L. were significantly higher than Gossypium hirsutum. Further studies in order to clarify effectors are recommended

Flow cytometric immunophenotyping of bone marrow in cats diagnosed with hematopoietic disorders

Cytological examination of bone marrow in cats, due to the large number of cells and various growth phases is somewhat complicated. The use of flow cytometric techniques and monoclonal antibodies are appropriate methods in the diagnosis of hematopoietic malignancies. The purpose of the present study is to determine cell-surface antigens for various developmental stages of feline bone marrow cells in hematopoietic disorders using flow cytometric. In this study, bone marrow cells from 4 cats with hematopoietic disorders and 2 clinically healthy cats, were labeled with 5 types of anti-feline MAbs included: CD21-like [Cr-Br], T lymphocyte subpopulation, CD-172a, Granulocyte, Pan-Leukocyte [CD45-like] and then analyzed using flow cytometric. The results revealed changes in immunophenotyping and light scatter properties compared with normal cases. The percentage of CD45, Granulocyte and CD172a markers in the bone marrow of a cat with erythroleukemia were lower compared with normal bone marrow. In a cat with myelodysplastic syndrome, scatter plot indicated an increase in the immature myeloid cells and a decrease in mature myeloid cells. It was concluded that cytological examination of bone marrow with studying dispersion studies on cells using flow cytometric and usage of a panel of antibodies such as CD21-like[Cr-Br], T lymphocyte subpopulation, CD-172a, Granulocyte, Pan-Leukocyte [CD45-like] could support the diagnosis of feline hematopoietic abnormalities

[Comparison of diagnostic accuracy of ultrasonography and radiology in radial critical-sized defects healing process in rabbit]

Healing of Critical-Sized Defects [CSDs] is one of the major challenges facing orthopedic surgeons. To assess the bone healing process usually plain radiography is used. Serial radiography results in certain side effects and recent findings are indicating the early detection of bone healing via ultrasonography. The purpose of current study is to compare the diagnostic accuracy of radiography and ultrasonography in healing process of radial CSDs in rabbit. Sixteen New Zealand White Rabbits were used in this study. The radial CSDs of 15 mm size were created in a routine surgical procedure described previously and the two diagnostic tools were compared 12 weeks post-surgery. In case of obtaining different results from radiology and ultrasonography, to determine which diagnostic imaging method is of more accuracy, the histopathologic results of samples from the same day were used. In 15 cases of 16, ultrasonography findings were confirmed by radiography and only in one case they were in contradiction, in which radiographs showed an Atrophic Nonunion while Ultrasound detected an outstanding filled defect with a reverberation artifact underneath. In histopathology, the defect was filled with an osteoid matrix of high cellularity and calcification was obvious in some regions, confirming the ultrasound results. This study indicates that in diagnostic imaging of CSDs, the ultrasonography and radiography are usually consonant and even ultrasound is more accurate than radiology. In addition, in case of detection of a reverberation artifact and lack of any healing-related finding in radiography, this artifact may be an indication of osteoid matrix formation

[ effects of age, sex and slaughtering on cellular distribution of bronchoalveolar lavage fluids in calves and cattle]

Based on our knowledge, there have been no studies about the effect of age, sex, lobe and slaughtering stress on cellular distribution of bronchoalveolar lavage fluids in calves and cattle in Iran. The main purpose of this study was to compare the cell distribution pattern of bronchial alveolar lavage fluids in calves and cattle in terms of age, sex, type of lung lobes and the stress of slaughtering. Bronchoalveolar lavage was performed in twelve calves at three different ages' groups [less than 2 months, 2-4 months and 4-6 months]. 250 milliliters sterile normal saline was infused through the tracheal tube and lavage was performed using syringe pressure. Post-mortem BAL was performed on twelve isolated lungs by infusing 150 milliliter normal saline. The lavage fluid was collected in sterile plastic tubes. The slide smears was prepared by pellet which were air-dried and stained with a Giemsa stain. Slides were evaluated cytologically. The data was analyzed by T-test, One Way ANOVA and post hoc Tukey test .Also, the Spearman correlation coefficient was used to assess the age and cell. Significant negative correlations were observed between cells such as epithelial cells, macrophages and mast cells, with a correlation coefficient of -0.430, - 0.059 and- 0.267- and age although the differences were not significant [p<0.01]. Statistically significant difference was observed in percentages of mast cells in males [1.48 +/- 1.25%] and females [zero percent] [p=0.04]. The differences were significant [p=0.019] between percentage of epithelial cells in the lungs of slaughtered cattle and lavaged lung of calves. The percentages of macrophages in slaughtered animals was significantly decreased [p=0.019] compared with live calves. Significant differences were not observed in cell density in different ages and sexes. But in the cell density in live animals [583 cells per microliter] was significantly higher than the lungs of slaughtered [237 cells per microliter] [p=0.03]. It seems that age and lobe do not affect pattern of lung immune cells. Sex and slaughtering stress, however may cause changes in immune cell type and density and lead to develop more respiratory disease

Cloning, nucleotide sequencing and bioinformatics study of NcSRS2 gene, an immunogen from Iranian isolate of Neospora caninum

Neosporosis is caused by an obligate intracellular parasitic protozoa Neospora caninum which infect variety of hosts. NcSRS2 is an immuno-dominant antigen of N. caninum which is considered as one of the most promising targets for a recombinant or DNA vaccine against neosporosis. As no study has been carried out to identify the molecular structure of N. caninum in Iran, as first step, we prepared a scheme to identify this gene in this parasite in Iran. Tachyzoite total RNA was extracted and cDNA was synthesized and NcSRS2 gene was amplified using cDNA as template. Then the PCR product was cloned into pTZ57R/T vector and transformed into E. coli [DH5alpha strain]. Finally, the recombinant plasmid was extracted from transformed E. coli and sequenced. Bioinformatics analysis also carried out. The PCR product of NcSRS2 gene was sequenced and recorded in GenBank. The deduced amino acid sequence of NcSRS2 in current study was compared with other N. caninum NcSRS2 and showed some identities and differences. NcSRS2 gene of N. caninum successfully cloned in pTZ57R/T. Recombinant plasmid was confirmed by sequencing, colony PCR and enzymatic digestion. It is ready to express recombinant protein for further studies

[Molecular study on Ehrlichia canis in thrombocytopenic dogs]

Infection with Ehrlichia canis, a gram negative obligatory intracellular bacterium, causes canine monocytic ehrlichiosis which is the worldwide disease in dogs. The objective of this study was to investigate the prevalence of E. canis in thrombocytopenic dogs using nested PCR and diagnostic role of thrombocytopenia in the infection. Blood samples collected from 40 dogs attended in Teaching small animal hospital of Tehran University were classified as group A [platelet counts below 101.000/microL, thrombocytopenic, n=11], B [101.000-200.000/microL, thrombocytopenic, n=15] and C [platelet counts more than 201.000/microL, non-thrombocytopenic, n=14] according to their platelet counts. 16S rRNA was analyzed by nested PCR using specific primers. 16S rRNA gene fragment of E. canis were detected in five samples of group A [45.5%], three samples of group B [20%], and one sample of group C [7.1%]. Prevalence rate of infection was statistically higher in group A than the other groups [p=0.02]. In total, approximately one third of thrombocytopenic dogs had demonstrable E. canis infection [30.7%]. While thrombocytopenia cannot be considered as specific marker for detection of E. canis infection, it can be used as a surveillance test prior to other diagnostic methods

Desmin expression by a gastrointestinal stromal tumor in a dog

This report describes the histological and immunohistochemical features of a small intestinal tumor that resembled a human gastrointestinal stromal tumor [GISTs] in a seven-year-old male cross-breed dog. This was unique because of the expression of desmin by the tumor. Grossly, the white-gray tumor measured 8.0x4.0x6.5 cm and was 760 gram in weight. It was cystic and enveloped the jejunum. Histopathologically, long spindle-shaped cells were arranged densely in the interwoven pattern. The tumor cells had a low rate of mitosis, were pleomorphic, and were positive for vimentin, alpha-smooth muscle actin, desmin, S100 and C-KIT and negative for CD34 on immunohistochemistry. The expression of desmin in the cytoplasm of this tumor cells is a rare event in these types of tumors

Immune-mediated hemolytic anemia in cats referring to Veterinary Teaching Hospital of Tehran [2006-2007]

Immune-mediated hemolytic anemia [IMHA] is characterized by the destruction of erythrocytes or sometimes bone marrow erythroid precursors mediated by immunoglobulins [IgG, IgM], with or without complement [C[3]]. The main objectives of this study were to assess the laboratory test results of IMHA and to investigate its possible underlying causes in cats referring to the Veterinary Teaching Hospital of Tehran. The Coombs' test [CT] was performed in 74 cats with PCV below 0.35. The test was positive in 26 cats. These positive CT cats were categorized into four groups based on the PCV ranges and type of anemia including: Group A: 9 of 26 cats had nonregenerative anemia [PCV median, 0.22] [1 feline leukemia virus positive which had erythroleukemia, 1 feline infectious peritonitis positive, 1 with Hemoplasma spp., 3 with renal failure, 2 with inflammatory disease and 1 with no diagnosis]. Group B: 4 cats [PCV median, 0.31] had a regenerative anemia with severe dehydration. Group C: the other 9 cats with a normal range of PCV [median, 0.34] involved with various conditions [vaccination, parturition, acetaminophen poisoning, osteoporosis, and renal failure]. Group D: the remaining 4 cats with a marginal range of PCV [median, 0.30] had a history of inflammatory disease and drug therapy. The results of this study indicated that infectious diseases and drug therapy were the main factors associated with positive Coombs' test results

Effects of ginger on spermatogenesis in streptozotocin-induced diabetic rat

Ginger rhizome [Zingiber officinale R., family: Zingiberaceae] is used medicinally and as a culinary spice. The medicinal use of ginger dates back to ancient China and India. Ginger and its constituents are stated to have antiemetic, antithrombotic antihepatotoxic, anti-inflammatory, stimulant, cholagogue and antioxidant. Enhanced oxidative stress and changes in antioxidant capacity are considered to play an important role in the pathogenesis of chronic diabetes mellitus. Wistar male rat [n=40] were allocated into three groups control group [n=10] and ginger [G] group that received l00mg/kg-perday [oral], [n=10], and Diabetic group that received 55 mg/kg [IP] streptozotocin [STZ] [n=20] which was subdivided to two groups of 10; STZ group and treatment group. Treatment group received 55mg/kg [IP] STZ plus ginger l00mg/kg-perday [G], daily for, 4 weeks, respectiveiy; however, the control group just received an equal volume of distilled water daily[IP]. Diabetes was induced by a single [IP] injection of streptozotocin C55 mg/kg]. Animals were kept in standard condition. In 28 day after inducing diabetic 5cc blood were collected for TAC, MDA and sperm parameters and testis tissues of Rat in whole groups were removed then prepared for analyzes. TAC, MDA and sperm parameters significantly decreased in diabetic group.treatment groub that has received Ginger 100 mg/kg [oral] show increasing in TAC and sperm parameters [p<0.05] in comparison to experimental groups [p<0.05]. Since in our study 100 mg/kg [oral] ginger have significantly Preventive effect on sperm parameters, so it seems that using it can be effective for treatment in Diabetic Rat

[Searching for Penicillium marneffei in the soil of Qazvin city]

Penicillium marneffei is a dimorphic fungus that produces disseminated infections in immune-deficient people and AIDS patients. This fungus is endemic to Southeastern Asia with its reservoir in Southeast Asian bamboo rats. Also, it has been isolated from rats of a region in India. This study was conducted to search for Penicillium marneffei fungus in the soil of Qazvin city from the spring of 2007 to spring of 2008. Samples were taken from different locations of the city and cultured on Sabouraud dextrose agar after preliminary processing in laboratory. A suspension from colonies suspected of penicillium marneffei species was prepared and injected into peritoneum of rats. Penicillium marneffei fungus was not found in soil of the city however, other fungi including Cladosporium spp., Aspergillus spp., Penicillium spp., Rhizopus spp., Alternaria spp., Mucor spp., Chrysosporium spp., Acremonium spp., Fusarium spp., Ulocladium spp., Drechselera spp., Scopulariopsis spp., and yeasts were cultured from the soil specimens. No Penicillium marneffei positive cultures were obtained from lung cultures of rats inhabiting the city. Although Penicillium marneffei fungus was not isolated from the city soil yet further researches on other locations of Iran are required to determine the presence or absence of this fungus

[Ultra-structure study of lead acetate cytotoxic effects on testis in rabbit]

Lead is one the world wide using metals it has been used since ancient time. It is also a toxin, known to have adverse effects on the body even at low level of exposure and it induces a bread range of physiological, biochemical, and behavioral dysfunctions. Studies have been showed that this metal has harmful effects on several tissues such as: nervous system, blood tissues, and cardiovascular system, reproductive and urinary system. Because it damage human, animal and plants. Nowadays has been attended on this metal. White male rabbits of New Zealand race were used and divided into two groups. Experimental groups [N=10] 6.5 Mg/Kg of lead acetate were injected intraperitoneally every other day to each animal for 7 weeks as chronic dose and control group [N=10] were injected only with demonized water. After taking biopsy from testis tissues of each group, tissue preparation was performed for LM and EM studies as standard method. Morphologic study was carried out on electron micrographs. Data have been compared using statistically methods. Morphological findings showed that testis tissue in experimental group that chronic dose has been sever changed histologically compared with control group. Seminifar tubules diameter showed significant decrease [p<0.05]. Primary Spermatocyte nucleus showed heterochromatin and mitochondria showed vacuelaution. These results [based on present study findings] revealed that lead acetate could have vivid effects on testis tissue during chronic dose

[ role of antioxidant vitamins on controlling hypercholesterolemia and cardiovascular diseases]

In observational studies, prolonged reduction in blood total cholesterol level is associated with lower risk of coronary heart disease however the results of clinical trials are controversial. During recent decades the role of antioxidants in preventing the initiation and progression of oxidative stress has been the focus of discussion. To systematically review and find the exact role of antioxidants in preventing atherosclerosis and secondary cardiovascular diseases [CVD]. The Medline database through 1991-2007 was carefully retrieved and 37 relevant papers selected. Findings: There are conflicting results in clinical trials regarding the efficacy of antioxidant vitamin supplements in reducing the progression of atherosclerosis and CVD events. Owing to several different factors of patients such as age, sex, health conditions, study duration, and also the type of studies, it was concluded that the judgment on benefit of antioxidants is accompanied with poor clarity. Thus, further future studies are needed to address the efficiency of such medications in reducing the effect of these two risk factors on human

[Alanin aminotransferase activity in veterans exposed to sulfur mustard]

Until now, few studies have focused on late effect of sulfur mustard on the liver; at present there is no data published on liver enzymes in sulfur mustard exposed veterans. The current study was conducted with the aim of determining alanine aminotransferase [ALT] levels in veterans exposed to sulfur mustard. In this cross-sectional study, 263 sulfur mustard exposed veterans were selected from among individuals referring to the respiratory clinic in Bagiyatallah hospital in 2005. ALT was determined in all subjects. Demographic data, exposure related variables, respiratory status and Body Mass Index [BMI] were collected. ALT over 40 unit/liter was considered as abnormal. From a total of 263 sulfur mustard exposed veterans, 43 [16.3%] patients had an elevated ALT level. Range of ALT was 3-94 with a mean [SD] of 26.43 +/- 15.22 unit/liter. ALT was correlated with the BMI [r=0.153, p=0.013]. ALT was not significantly correlated with age, grading of chemical and overall disability. Mean ALT levels in patients with BMI > 25 [28.81 +/- 15.05] were significantly higher than those with BMI less than 25 [21.93 +/- 14.58] [p=0.001]. Mean ALT level was higher in those with FEV1/FVC, in comparison to others [p<0.05]. ALT was not significantly correlated with other study variables [p>0.05]. Although any conclusion of the impact of mustard gas on ALT needs a controlled study, we mean while suggest serial measurement of the activity of this enzyme and other measures of liver status

[Home drug store in Minodar region of Qazvin [2006]]

Self-medication, consumption of expired drugs and storage of medicines in unsuitable conditions causes both loss of scarce resources and health hazards. To determine the amount of home drug storage and the reasons for such attitude. This was a descriptive study conducted on 85 families in Minodar region of Qazvin [Iran] in 2006. Drugs were clustered based on OTCs, clinical application, expiration date, and storage conditions. Drug storage with no usage was seen in 82.4% out of 85 families. The frequency for distribution of the prescribed drugs was 73.1% [tablets], 98% [capsules], 75.5% [ointments], 83.1% [drops], 54% [syrups], 25% [suppositories], and 100% [ampoules]. The majority of expired drugs in every single family were related to gastrointestinal drugs. Storage conditions were found to be different from one family to another, irrespective of the manufacturer' s instruction. Regarding the volume of home drug storage and the quality by which the drugs are stored, increasing the public's general knowledge on drug application and storage conditions to prevent therapeutic failure and also lowering the adverse effect is necessary

Anticonvulsant effects of Pasipay [prepared from passion flower] by PTZ model in the mice

Passion flower has shown antianxeity and sedative effects in human. In this study, anticonvulsant effects of hydroalcoholic extract of passiflora were studied. Anticonvulsant effects of Pasipay were examined by using pentylenetetrazole model [PTZ] on mice. In this research pasipay, diazepam, and normal saline were injected i.p. at doses [0.05-0.4 mg/kg], [0.5-1 mg/kg], [10 ml/kg] respectively and after 30 minutes, PTZ [90 mg/kg, i.p] was injected to these mice. For investigating the mechanism of pasipay, flumazenil [2 mg/kg, i.p] and naloxone [5 mg/kg, i.p] were also injected 5 minutes before pasipay. An ED[50] value of pasipay was 0.2 mg/kg [%95 CL: 0.119, 0.408]. In this model, pasipay at the dose of 0.4 mg/kg prolonged the onset time of seizure and decreased the duration of seizures compared to control [p<0.001]. In this dose the seizure and mortality protection was 100%. Flumazenil and naloxone could suppress anticonvulsant effects of pasipay. It seems that pasipay may be useful for treatment of absence seizure and these effects may be related to the effect of it on GABAergic and opioid systems

Review of antiviral effects of Glycyrrhiza glabra l. and its active component, glycyrrhizin

Licorice [Glycyrrhiza sp.] belongs to family of Leguminosae. A number of components have been isolated from licorice, including triterpene saponins, flavonoids, isoflavonoids, chalcones and various other substances. Glycyrrhizic acid is the main biologically active component of it. The aim of this review is to provide an updated overview of experimental investigations focused on the antivirus effects of Glycyrrhiza and its active. A computerized search of published articles was performed using the electronic database such as MEDLINE from 1980 to 2005. Glycyrrhiza exerts antiviral activity toward a number of viruses, including hepatitis A, B, C, varicella zoster, HIV, Herpes simplex type-1, SARS, cytomegalo virus. Now glycyrrhizic acid has been used for the treatment of the patients with chronic active hepatitis and about the mechanism of glycyrrhizin's activity against other viruses, it seems that glycyrrhizin inhibits replication, affects cellular signaling pathways, upregulate expression of inducible nitrous oxide synthase and production of nitrous oxide in macrophages. Thus, it seems that future clinical research is needed to define the possible use of licorice and it active component, glycyrrhizic acid as effective antivirus agents for treatment other viral infections

[Effects of Vitamins E and C on sperm characteristic in vitro]

Effect of vitamins E and C on bull's sperm during refrigeration was studied. Semen was collected from a healthy bull and diluted with an extender to 20 x 10[6]/ ml. The extended semen was divided into 3 equal parts and each one received either vitamin E [T[1] = 40 micro g/ml], vitamin C [t[2] = 200 micro g/ml] or neither one [T[3] = 0]. eight samples [ependorf = 1 ml] from each treatment were made and placed in refrigerator [5 C] for four days. The treatments were evaluated during 4 days according to: E[1], C[1]=24, E[2], C[1] = 48, E[3], C[3] = 72 and E[4], C[4] = 96 hours. Every day 2 samples from each treatment were selected randomly and evaluated for PH, %SNM, FSC, SMI, MSC, %PSM and TSC. The control treatment was measured in the first day and the C[4] treatment due to death of sperms was not evaluated. The level of pH for E[1] treatment significantly increased when compared to control group. Number of nomal sperm in treatments E[1]. E[2] and C[1] were increased when compared to control group [p< 0.01]. Also, treatment E[1], E[2] and C[1] were showed significantly increase for FSC when compared to control group where as E[4], C[2] and C[3] were reduced [p< 0.01]. The percent SMI in E[1], E[2] and C[1] treatments was increased significantly in comparsion to control group while E3 and C[2] treatments didn't differ but E[4] and C[3] treatments were shon reduction [p< 0.01]. The amount of MSC in E[1], E[2] and C[1] treatments were increased significantly when compared to control group but E[3], E[4] and C[2] treatments didn't differ; however the C[3] showed significantly decrease [p< 0.01]. The percent PSM in E[1], E[2] and C[1] treatment were increased in comparsion to control group [p< 0.01], where as the E[3], E[4] and C[2] had no differences but the C[3] showed significantly decrease. The sperm concentration in E[1], E[2] and C[1] treatments were increased significantly in comparsion to control group but the E[3], E[4] and C[2] treatments did not differ. The resultes of this study showed that adding vitamin E [40 micro g/ml] or vitamin C [200 micro g/ml] to semen may prevent sperm membrane destruction at least for 48 or 24 hours during refrigeration receptively, thus the quality of sperm will improve

effects of carbenoxolone, a gap junction channel blocker, on spatial learning inMorris water maze task in rats

High frequency oscillations [ripples] are proposed to involve in memory consolidation. Ripple oscillations persist in the absence of chemical synaptic transmission and inhibitors of gap junctions were shown to block high frequency oscillations in hippocampal slices. In this study, we investigated the effects of carbenoxolone, as a gap junction blocker, on spatial learning in the rat. Cognitive performance was assessed using Morris water maze [MWM]. Adult male rats were bilaterally cannulated into the CA1 region of their hippocampus. Carbenoxolone [1.23, 2.46, 4.92 microg/side], scopolamine [microg/side] and saline were injected through the cannulas before training for 4 consecutive trials and one probe trial that was conducted 24 h after the training trials with the platform removed. The results showed that carbenoxolone could significantly reduced percent of time spent, distance traveled and quadrant entry in Q2 compared to control group and failed to use a selective search strategy during probe trial in which the platform was removed.The results of the present study suggest that carbenoxolone as a gap junction channels blocker can decelerate learning performances of rats in a spatial memory task such as the MWM that requires the integrity of hippocampus

Study on the anticonvusant activity of thymoquinone, the major constituent of Nigella Sativa L.seeds, through intracerebroventricular injection

Thymoquinone, the major constituent of Nigella sativa seeds, is a biologically active compound, which possesses several pharmacological effects. The aim of the present study was to evaluate the anticonvulsant effect of thymoquinone through intracerebroventricular [i.c.v.] injection. The anticonvulsant effects of thymoquinone, the major constituent of Nigella sativa seeds, were investigated using pentylenetetrazole [PTZ]-induced seizure model. In PTZ-induced epileptic seizures, the i.c.v. injection of thymoquinone [200 and 400 mol] prolonged the onset and reduced the duration of tonic-clonic seizures. The protective effect of thymoquinone against lethality was 45% and 50% in the mentioned doses, respectively. In this study, flumazenil [1 nmol, i.c.v.] reversed the anticonvulsant activity of thymoquinone. Also, pretreatment with naloxone [10 mol, i.c.v.] antagonized the prolongation of tonic-clonic seizure latency, as well as reduction in seizure duration both induced by thymoquinone [200 mol, i.c.v.]. These results indicate that thymoquinone may possess anticonvulsant activity probably through an opioid receptor-mediated increase in GABAergic tone