Green tea polyphenol epigallocatechin-3-gallate attenuates behavioral abnormality in hemi-parkinsonian rat

Background: Epigallocatechin gallate (EGCG), a major constituent of green tea, has been introduced as a potent free radical scavenger and can effectively reduce free radical-induced lipid peroxidation. Since free radical injury plays an important role in neuronal damage in Parkinson's disease (PD), this study examined whether EGCG administration would reduce functional asymmetry in an experimental model of PD in male Wistar rats. Methods: For this purpose, unilateral intrastriatal 6-hydroxydopamine-lesioned rats were intraperitoneally pretreated with EGCG (40 mg/Kg) 2 hours before surgery and daily (20 mg/Kg) for a period of 2 weeks post-surgery. Apomorphine- and amphetamine-induced rotations were measured pre- and post-surgery after 2 weeks. Results: The results showed that there are 35.1 (P<0.05) and 33.2 (P<0.05) reductions in controversies apomorphine- and ipsiversive amphetamine-induced rotations in EGCG-treatedlesioned group respectively as compared to the untreated lesioned group at 2nd week post-surgery. Conclusion: Taken together, these results showed that two-week administration of EGCG could attenuate the drug-induced behavioral abnormalities in this model of PD

Antinociceptive effect of Allium schoenoprasum L. oral feeding in male diabetic rats

زمینه و هدف: هیپرآلژزی یکی از علایم بارز دیابت قندی در میان مدت محسوب می شود که بر کیفیت زندگی افراد مبتلا تاثیر دارد. در این بررسی اثر ضد دردی تجویز خوراکی و دراز مدت برگ سیر کوهی در موش های صحرایی دیابتی شده مورد ارزیابی قرار گرفت. روش بررسی: در این مطالعه تجربی 40 راس موش صحرایی به پنج گروه کنترل، کنترل تحت تیمار با گیاه، دیابتی دریافت کننده سدیم سالیسیلات، دیابتی و دیابتی تیمار شده با گیاه تقسیم شدند. دو گروه تحت تیمار با گیاه، پودر برگ مخلوط شده این گیاه با غذای استاندارد موش (3) را به مدت 8 هفته دریافت نمودند. در پایان کار، میزان احساس درد با استفاده از آزمون های فرمالین و غوطه وری دم در آب داغ تعیین شد. میانگین درد در ده دقیقه اول بعد از تزریق فرمالین به عنوان مرحله حاد و در دقایق 16 تا 60 به عنوان مرحله مزمن در نظر گرفته شد. یافته ها: درمان با برگ گیاه سیر کوهی موجب کاهش معنی دار نمرات درد موش های دیابتی از 14/0±41/2 به 12/0±01/2 فقط در مرحله مزمن آزمون فرمالین گردید (05/0

The role of L-type calcium channels in the vascular effect of Trigonella foenum-graecum L. in diabetic rats

Some ion channels like voltage-operated calcium channels (VOCC) within the plasma membrane of vascular muscle cells from the walls of resistance arteries and arterioles play a central role in the regulation of vascular tone. On the basis of reports about the beneficial attenuating effect of fenugreek (Trigonella foenum-graecum L.; TFG) on the contractile reactivity of aortic rings of diabetic rats, this study was carried out to evaluate the possible involvement of L-type voltage-operated calcium channels in the vascular effect of this medicinal plant. For this purpose, male Wistar rats were made diabetic using streptozotocin (STZ, 60 mg/Kg, i.p). The extract-treated control and diabetic rats received aqueous leaf extract of TFG (200 mg/Kg, i.p.) every other day for two months. At the end of the study, contractile response of isolated aortic rings to KCl and noreadrenaline (NA) was determined in the absence and presence of the calcium channel blocker nifedipine. The results showed that aortic rings from diabetic rats are more responsive to the effect of KCl and NA than those of controls, TFG extract treatment could attenuate the enhanced contractile response of aortic rings of diabetic rats, and nifedipine pretreatment could partially neutralize the beneficial effect of this extract. It is concluded that TFG extract attenuates the enhanced vascular reactivity in chronic diabetic rats and voltage-operated calcium channels are in part responsible for this effect of TFG extract

Quinapril attenuates the effect of long-term L-NAME administration on the vascular reactivity of diabetic rats

Angiotensin-converting enzyme (ACE) inhibitors including quinapril could exert a protective effect on cardiovascular system through endothelial system in normoglycemic and diabetic rats. The present experimental work was designed to study the vascular reactivity of aortic ring segments isolated from streptozotocin (STZ)-diabetic rats treated for 4 weeks with nitro-L-arginine- methyl ester (L-NAME; 50 mg/100 ml) or L-NAME plus quinapril (10 mg/100 ml) in drinking water. The results showed that quinapril treatment significantly attenuated the augmented contractile response to phenylephrine and KCl in diabetic rats. In addition, quinapril treatment partially restored the reduced contractile response in diabetic animals treated chronically with L-NAME. It can be concluded that quinapril could partly counteract the effect of long-term L-NAME administration on vascular reactivity in STZ-diabetic rats

Antinociceptive effect of Teucrium polium leaf extract in the diabetic rat formalin test

This Study was designed to evaluate the analgesic effect of Teucrium polium leaf extract in the diabetic rat formalin test. For this purpose, streptozotocin (STZ)-diabetic rats received intraperitoneal injection of this extract (100 and 200 mg/kg per day) for a period of 2 weeks. It was found out that Teucrium polium-treated diabetic rats exhibited a lower nociceptive score as compared to untreated diabetics. The results may suggest therapeutic potential of Teucrium polium extract for the treatment of diabetic hyperalgesia. (C) 2004 Elsevier Ireland Ltd. All rights reserved

Pelargonidin improves passive avoidance task performance in a rat amyloid beta25-35 model of Alzheimer�s disease via estrogen receptor independent pathways

Alzheimer�s disease (AD) is a disorder with multiple pathophysiological causes, destructive outcomes, and no available definitive cure. Pelargonidin (Pel), an anthocyanin derivative, is an estrogen receptor agonist with little estrogen side effects. This study was designed to assess Pel memory enhancing effects on the a rat Amyloid Beta25-35 (Aβ) intrahippocampal microinjections model of AD in the passive avoidance task performance paradigm and further evaluate the potential estrogen receptor role on the memory- evoking compound. Equally divided rats were assigned to 5 groups of sham, Aβ intrahippocampal microinjected, Pel pretreated (10 mg/kg; P.O), α estrogen antagonist intra-cerebrovascular (i.c.v.) microinjected, and β estrogen antagonist (i.c.v) microinjected animals. Intrahippocampal microinjections of Aβ were adopted to provoke AD model. Passive avoidance task test was also used to assess memory performance. Pel pretreatment prior to Aβ microinjections significantly improved step-through latency (P<0.001) in passive avoidance test. In α and β estrogen, antagonists received animals, passive avoidance task performance was not statistically changed (P=0.11 & P=0.41 respectively) compared to Pel pretreated and sham animals. Our results depicted that Pel improves Aβ induced memory dysfunction in passive avoidance test performance through estrogen receptor independently related pathways. © 2016 Tehran University of Medical Sciences. All rights reserved

Time course of changes in passive avoidance and Y-maze performance in male diabetic rats

Diabetes mellitus is accompanied with disturbances in learning, memory, and cognitive skills in the human society and experimental animals. Therefore, this research study was conducted to evaluate time-dependent changes in passive avoidance and Y-maze performance in male diabetic rats. For this purpose, male Wistar rats were randomly divided into control and diabetic groups. For induction of diabetes, streptozotocin (STZ) was injected i.p. at a single dose of 60 mg/kg. For evaluation of learning and memory, initial latency (IL) and step-through latency (STL) were determined at the end of 1st, 2nd, and 3rd months using passive avoidance and Y-maze tasks. It was found out that mean IL exhibits a significant increase only at the end of 2nd (p&lt;0.05) and 3rd (p&lt;0.01) months. In addition, STL significantly reduced at the end of 2nd (p&lt;0.05) and 3rd months (p&lt;0.01). Regarding Y-maze task, alternation score of the diabetic rats was lower than that of the control ones at the end of 1st (p&lt;0.05), 2nd (p&lt;0.01), and 3rd (p&lt;0.01) months as compared to time-matched control group. To conclude, at least one month is strictly required for development of behavioral disturbances in passive avoidance and Y-maze tasks in STZ-diabetic rats

Chronic oral pelargonidin alleviates streptozotocin-induced diabetic neuropathic hyperalgesia in rat: Involvement of oxidative stress

Background: Diabetes mellitus in some clinical cases is accompanied with hyperalgesia. In this study, we evaluated the possible beneficial effect of chronic pelargonidin (PG) treatment on hyperalgesia in streptozotocin (STZ)-diabetic neuropathic rat. Methods: Male Wistar rats (n = 56) were divided into seven groups, i.e. control, diabetic, PG-treated control, PG (single- and multiple-dose)-treated diabetic, and sodium salicylate-treated control and diabetics. For induction of diabetes, STZ was injected i.p. at a single dose of 60 mg/kg. PG was orally administered at a dose of 10 mg/kg once and/or on alternate days for 8 weeks; 1 week after diabetes induction. After two months, hyperalgesia was assessed using standard formalin and hot tail immersion tests. Meanwhile, markers of oxidative stress in brain were measured. One-way analysis of variance was used for statistical analysis of the data. Results: Diabetic rats showed a marked chemical and thermal hyperalgesia, indicating that development of diabetic neuropathy and PG treatment (especially multiple-doses) significantly ameliorated the alteration in hyperalgesia (P<0.05-0.01) in diabetic rats as compared to untreated diabetics. PG (multiple doses) also significantly decreased diabetes-induced thiobarbituric acid reactive substances formation and non-significantly reversed elevation of nitrite level and reduction of antioxidant defensive enzyme superoxide dismutase. Conclusion: These results clearly suggest that PG prevents diabetic neuropathic hyperalgesia through attenuation of oxidative stress

Mechanisms underlying quercetin-induced vasorelaxation in aorta of subchronic diabetic rats: an in vitro study

In this study, the mechanisms involved in vasorelaxant effect of the flavonoid quercetin was investigated in isolated aortic rings from streptozotocin (STZ)-diabetic rats. After 4 weeks, addition of quercetin (0.1 muM-1 mM) caused a significant dose-dependent relaxation of noradrenaline (NA)- and KCl-preconstricted rings in both control and diabetic groups with a significant inter-group difference of P<0.01. Furthermore, both nitro-L-arginine-methyl ester (L-NAME, 100 muM) and indomethacin (10 muM) markedly attenuated the vasorelaxant responses following quercetin application. Meanwhile, endothelium removal significantly attenuated the quercetin-induced vasorelaxation. It is concluded that the quercetin can relax the preconstricted rings of aorta in subchronic STZ-diabetic rats through nitric oxide- and prostaglandin-mediated pathways, which themselves could be considered as endothelium-dependent. (C) 2004 Elsevier Inc. All rights reserved

Chronic rumex patientia seed feeding improves passive avoidance learning and memory in streptozotocin-diabetic rats

Introduction: Diabetes mellitus is accompanied with disturbances in learning, memory, and cognitive skills in the human society and experimental animals. Due to anti-diabetic and antioxidant activity of Rumex patientia (RP), this research study was conducted to evaluate the efficacy of chronic Rumex patientia feeding on alleviation of learning and memory disturbance in streptozotocindiabetic rats. Methods: Male Wistar rats were divided into control, diabetic, RP-treatedcontrol and -diabetic groups. For induction of diabetes, streptozotcin (STZ) was administered at a dose of 60 mg/Kg. Meanwhile, RP-treated groups received RP seed powder mixed with standard pelleted food at a weight ratio of 6 for 4 weeks. For evaluation of learning and memory, initial latency (IL) and step-through latency (STL) were determined at the end of study using passive avoidance test. Results: It was found out that regarding initial latency, there was no significant difference among the groups. In addition, diabetic rats developed a significant impairment in retention and recall in passive avoidance test (p<0.01), as it is evident by a lower STL. Furthermore, RP treatment of diabetic rats did produce a significant improvement in retention and recall (p<0.05). Discussion: Taken together, chronic RP feeding could improve retention and recall capability in passive avoidance test in STZ-diabetic rats