The interactive effects of verapamil and CB1 cannabinoid receptor antagonist/inverse agonist, AM251 on passive avoidance learning and memory in rat.

There are reports regarding the effects of intracellular Ca2+ and synthesis and release of endocannabinoids. The secretion of endocannabinoids depends on the L-type calcium channel. The present study evaluated the involvement of the cannabinoid CB1 receptors in the effect of L-type calcium channel blocker verapamil on passive avoidance learning (PAL) in adult male rats. In this study, we examined the effects of an acute administration of the cannabinoid CB1 receptors antagonist/inverse agonist AM251 following a chronic administration of the Ca2+ channel blocker verapamil on PAL. Male Wistar rats were administered verapamil (10, 25 and 50 mg/kg) or saline intraperitoneally (i.p) daily for 13 days (n = 10/group). After this treatment period, a learning test (acquisition) was performed, and a retrieval test was performed the following day. The results indicated that chronic systemic administration of verapamil (in a dose-dependent manner) impaired memory acquisition and retrieval. Pre-training acute administration of a selective CB1 antagonist/inverse agonist, AM251 (5 mg/kg, i.p.) did not change memory acquisition and retrieval. Co-administration of the verapamil and AM251 significantly reversed verapamil-induced amnesia, suggesting a functional interaction between AM251 and verapamil. The results indicated the interactive effects of cannabinoid CB1 receptors and L-type calcium channel in passive avoidance learning and AM251 can counter the effects of verapamil on memory.

Conditioned medium of bone marrow mesenchymal stem cells improves sperm parameters and reduces histological alteration in rat testicular ischaemia/reperfusion model.

Testis ischaemia-reperfusion (I/R) plays a vital role in male infertility. Recent studies have demonstrated that paracrine factors of mesenchymal stem cells exert the transplanted cells' reparative effects. The present experimental study aimed to investigate the effects of conditioned medium (CM) of bone marrow-derived mesenchymal stem cells (BMMSCs). In this study, 21 rats were separated into three groups of 7 animals: sham, I/R and I/R plus CM. Sperm parameters were measured at the end of this study. Moreover, histological parameters were examined. 2-Deoxyuridine 5-triphosphate nick-end labelling (TUNEL) assay was done to assess the apoptotic cells. The count of adhered neutrophils was measured in subtunical venules. Testicular I/R led to a significant reduction in the viability and concentration of sperm and resulted in a significant elevation in the rate of abnormal sperms in comparison with sham. The CM-treated group demonstrated a significant reduction in the rate of abnormal sperm and a significant elevation in the viability and concentration of sperm compared with the I/R group. Based on the morphometric analysis, in the I/R group, epithelial thickness and seminiferous tubule diameter significantly decreased in comparison with sham. A significant reduction was seen between the I/R and sham groups regarding the mean testicular biopsy score (MTBS) value. However, an improvement was observed in the I/R + CM group MTBS value in comparison with the I/R group. TUNEL assay showed that the apoptotic cells in the seminiferous tubules belonging to the I/R group were significantly higher compared with the control. Nevertheless, apoptotic cells were reduced in the I/R + CM group compared with the I/R group. Results of the present study showed that CM of BMMSCs exerts protective effects on the testicular I/R damages.

Ce-Mn ferrite nanocomposite promoted the photosynthesis, fortification of total yield, and elongation of wheat (Triticum aestivum L.).

Recent advances in nano-enabled agriculture raised hope in the efficient delivery of bioactive minerals to crops. Nanocomposites (NCPs) are promising technologies in soil fertilizing without compromising environmental contamination. NCPs have shown positive impacts on plant growth and nanofortification of crop yield. Here, we have synthesized a nanocomposite that could induce the positive impacts of the Mn, Fe, and Ce nanoparticles for the crops. The NCPs were extensively characterized and applied at three levels 100, 250, and 500 ppm on T. aestivum L. seeds for 10 days. The germination, biomass, and elongation have been measured as the main physiological parameters of the plant. The total content of chlorophyll, carotenoids, and enzymatic and non-enzymatic antioxidant in response to NCPs was quantified. The concentration of essential minerals (iron and manganese) and the non-essential element of cerium in roots and shoots were quantified using inductively coupled plasma mass spectrometry (ICP-MS). Briefly, the germination rate increased by 15%; total chlorophyll and carotenoid were augmented by 61% and 38%, respectively, in exposure to 100 ppm. Higher uptake of micronutrient Fe and Mn in shoots and led to higher yield production by 14% and 18%, respectively. A positive correlation between the increasing dose of NCPs and the total content of the superoxide dismutase (SOD), and peroxidase (POD) were quantified. Overall, the results indicate the high potential of NCPs applications in agricultural practice.

Beneficial effects of rutin in diabetes-induced deficits in acquisition learning, retention memory and pain perception in rats.

Objectives: Cognitive impairment and hyperalgesia are among the common manifestations of diabetes. Hyperglycemia may contribute to their developments but the exact pathophysiology underlying these complications is not fully understood. Flavonoids from plants original have beneficial effects on diabetes by improving glycemic control. Rutin (RUT) is a bioflavonoid found in many plants and foods with many biological activities including neuroprotective and antidiabetic effects. In this study, we hypothesized that administration of RUT (10, 25 and 50 mg/kg, i.g.) for 30 days in rats would affect on hyperglycemia, cognitive dysfunction and hyperalgesia, which are common complications of diabetes type I. Methods: Diabetes was induced by streptozotocin (STZ) injection which destroys ß-cells and induces clinical features in animals that resemble those in diabetes type I in humans. Therefore, STZ-treated animals are used for the evaluation of novel antidiabetic drugs. The animals received vehicle or RUT (10, 25 and 50 mg/kg, i.g., once daily) at the onset of hyperglycemia for 30 days. Learning and memory was assessed by passive avoidance learning and memory test in streptozocin-induced diabetic and non-diabetic rats. Chemical hyperalgesia was evaluated by the formalin test. Results: Diabetes-induced deficits in acquisition and retrieval processes. RUT (25 and 50 mg/kg) reversed learning and memory deficits in diabetic rats. These doses of RUT reversed chemical hyperalgesia during both phases of the formalin test in diabetic rats and induced antinociceptive effects in healthy animals. RUT 10 mg/kg did not alter behaviors in control and diabetic groups. RUT 50 mg/kg induced significant hypoglycemic effects in both diabetic and non-diabetic rats. Discussion: Prolonged oral administration of RUT (25 and 50 mg/kg) induced cognitive enhancing and antinociceptive effects in both control and diabetic rats. Therefore, it may represent a potential therapeutic option against diabetic neurological disorders which deserves consideration and further examination.

The effects of cinnamaldehyde on acute or chronic stress-induced anxiety-related behavior and locomotion in male mice.

Anxiety and stress are considered as universal psychiatric exhibitions of the present societies and lifestyles. Several experiments have been conducted to examine natural anxiolytic agents to find out an alternative to synthetic anxiolytic drugs. The present study investigated the anxiolytic effects of cinnamaldehyde (Cin) on mice behavior in the elevated plus maze (EPM) and open field (OF) tests. Sixty male Swiss mice, weighing 20-30 g, were divided into six groups including: acute stress + mazola oil; chronic stress + oil; acute stress + Cin (20 mg/kg); chronic stress + Cin; non-stress + oil; and non-stress + Cin groups. The groups were administered for seven days (once a day). The acute stress + Cin group showed a meaningful rise in the percentage of entries into the open arms compared to the acute stress + oil group (p <.05). The percentage of time spent in the open arms in the chronic stress + Cin group was significantly higher compared to the chronic stress + oil group (p < .01). The percentage of entries into the open arms increased significantly (p < .01) in the chronic stress + Cin group in comparison with the chronic stress + oil group. The Cin treated groups showed significant increases in the time spent in the center area and in the number of entries into the center area compared with the oil treated groups in OF test. The number of entries into the arms (total activity), as well as locomotor activity was not significant among groups. The results of the present study indicated that Cin, as a natural product, might have anxiolytic effects in mice behavior in the EPM and OF tests. Lay summary The results demonstrated that the administration of cinnamaldehyde (Cin) produced anxiolytic effects in mice. Natural antioxidant products have been reported effective for anxiety. Synthetic medications have notable adverse effects. Therefore, these natural substances with broad therapeutic applicability are able to reduce anxiety-related behavior with rare side effects. According to the results, Cin could decrease anxiety-related behavior in mice.

Vitamins C and E alone and in combination partly protect against chronic ethanol-induced toxicity in rat erythrocytes.

Oxidative stress is part of the mechanisms involved in ethanol toxicity. We investigated effects of vitamins C (VC), E (VE) and the combination of VC+VE on chronic ethanol-induced toxicity in rat erythrocytes. The following groups were treated for 30 days: control (C), VC (200 mg/kg), VE (200 mg/kg), VC (200 mg/kg) + VE (200 mg/kg), ethanol 4 g/kg, ethanol + VC, ethanol + VE and ethanol + VC + VE. The doses of vitamins and ethanol were selected for per kilogram of animal's body weight. Blood samples collected at the end of treatments were analyzed for erythrocyte osmotic fragility and plasma scavenging activity. The washed erythrocytes were used to determine superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and malondialdeyde (MDA). Ethanol induced erythrocyte fragility (p < 0.001) and increased lipid peroxidation (p < 0.001) in rat erythrocytes. Furthermore, there were significant decreases in plasma scavenging (p < 0.001), SOD (p < 0.001), CAT (p < 0.01) and GPx (p < 0.001) activities in erythrocytes of ethanol-treated animals. Although VC or VE alone restored all of ethanol-induced disturbances to near normal (p > 0.05) but there were still significant differences compared to control animals. Combination therapy completely corrected ethanol-induced erythrocyte fragility, lipid peroxidation and prooxidant/antioxidant imbalance. We showed the beneficial effects of VC and VE combination in decreasing erythrocyte fragility and lipid peroxidation in both ethanol and control groups. Therefore this combination treatment may provide a new potential alternative for prevention of ethanol toxicity which deserves consideration and further examination.

Beneficial effects of rosmarinic acid against alcohol-induced hepatotoxicity in rats.

Alcohol is a severe hepatotoxicant that causes a variety of liver disorders. Rosmarinic acid (RA), a natural phenol, shows some biological activities, including antioxidant and anti-inflammatory effects. We investigated the effects of RA (10 mg/kg) against ethanol-induced oxidative damage and hepatotoxicity in rats. Animals received ethanol (4 g/kg, i.g.) and (or) RA (10 mg/kg, i.g.) daily for 4 weeks. At the end of the treatment period, rats were weighed and use for biochemical, molecular, and histopathological examinations. Ethanol increased hepatic lipid peroxidation (P < 0.001) and decreased hepatic levels of reduced glutathione (P < 0.01), catalase (P < 0.05), and superoxide dismutase (P < 0.001) compared with control group. RA prevented the prooxidant and antioxidant imbalance induced by ethanol in liver. Furthermore, RA ameliorated the increased liver mass, serum levels of ALT, AST, LDH, TNF-α, and IL-6 in ethanol group. Necrosis and infiltration of inflammatory cells in liver parenchyma were attenuated by RA treatment. Our findings showed that RA prevents ethanol-induced oxidant/antioxidant imbalance and liver injury in an experimental model of ethanol-induced hepatotoxicity. Therefore, RA may be a good candidate to protect against ethanol-induced hepatotoxicity; this deserves consideration and further examination.

Rosmarinic acid protects against chronic ethanol-induced learning and memory deficits in rats.

OBJECTIVES: Ethanol consumption induces neurological disorders including cognitive dysfunction. Oxidative damage is considered a likely cause of cognitive deficits. We aimed to investigate the effects of rosmarinic acid (RA) in different doses for 30 days on chronic ethanol-induced cognitive dysfunction using the passive avoidance learning (PAL) and memory task in comparison with donepezil, a reference drug. We also evaluated the levels of superoxide dismutase (SOD), catalase (CAT), and lipid peroxidation in hippocampus as possible mechanisms. METHODS: Memory impairment was induced by 15% w/v ethanol (2 g/kg, i.g.) administration for 30 days. RA (8, 16, and 32 mg/kg, i.g.) or donepezil (2 mg/kg, i.g.) was administered 30 minutes before ethanol. The acquisition trial was done 1 hour after the last administration of RA and donepezil. At the end, animals were weighed and hippocami were isolated for analyzing of oxidant/antioxidant markers. RESULTS: Ethanol caused cognition deficits in the PAL and memory task. While RA 16 and 32 mg/kg improved cognition in control rats, it prevented learning and memory deficits of alcoholic groups. RA 8 mg/kg did not influence cognitive function in both control and alcoholic rats. RA 32 mg/kg had comparable effects with donepezil in prevention of acquisition and retention memory impairment. The higher doses of RA not only prevented increased lipid peroxidation and nitrite content but also decreased SOD, CAT, GSH, and FRAP levels in alcoholic groups and exerted antioxidant effects in non-alcoholic rats. DISCUSSION: We showed that RA administration dose-dependently prevented cognitive impairment induced by chronic ethanol in PAL and memory and disturbed oxidant/antioxidant status as a possible mechanism. The antioxidant, anticholinesterase, and neuroprotective properties of RA may be involved in the observed effects. Therefore, RA represents a potential therapeutic option against chronic ethanol-induced amnesia which deserves consideration and further examination.

Chelating effects of carnosine in ameliorating nickel-induced nephrotoxicity in rats.

The kidney is one of the main organs affected by nickel toxicity. We investigated the protective effects of carnosine on nickel-induced oxidative stress in kidney of rats. Animals received NiSO4 (20 mg·kg-1·day-1 intragastrically) and (or) carnosine (10 mg·kg-1·day-1 intragastrically) for 21 days and then were evaluated for biochemical, molecular, and histopathological alterations. Nickel caused an increase in renal levels of malondialdehyde and a decrease in reduced glutathione, catalase, and superoxide dismutase levels and total antioxidant capacity. Carnosine prevented the prooxidant and antioxidant imbalance induced by nickel. Nickel-treated rats showed an increase in serum creatinine, urea, and uric acid with a concomitant decrease in albumin. Nickel markedly accumulated in kidney of exposed rats, but its concentration was effectively reduced by carnosine treatment. Carnosine corrected the biochemical abnormalities and the elevated renal TNF-α and IL-6 levels in the nickel-treated group. It also attenuated nickel-induced abnormalities in renal architecture. Although carnosine showed antioxidant and anti-inflammatory effects in renal tissue of nickel-exposed rats, we cannot clearly attribute the protective effect of carnosine to these effects. Instead, the beneficial effect of carnosine observed in the current study may be due to chelation between nickel and carnosine. Thus, carnosine may represent a therapeutic option to protect against nickel-induced nephrotoxicity that deserves further consideration and examination.

Effects of rosmarinic acid on acetaminophen-induced hepatotoxicity in male Wistar rats.

CONTEXT: Drug-induced liver injury is a significant worldwide clinical problem. Rosmarinic acid (RA), a natural phenol, has antioxidant effects. OBJECTIVE: The effects of RA against acetaminophen (N-acetyl-p-amino-phenol (APAP))-induced oxidative damage and hepatotoxicity in rats were investigated. MATERIALS AND METHODS: Male Wistar rats were pretreated with RA (10, 50 and 100 mg/kg, i.g.) for one week. On day 7, rats received APAP (500 mg/kg, i.p.). Then aspartate aminotransferase (AST), alanine aminotransferase (ALT), albumin, total protein, malondialdehyde (MDA), glutathione (GSH), total antioxidant capacity (TAC), glutathione S-transferase (GST), cytochrome CYP450 and histopathological changes were determined. RESULTS: APAP-induced oxidative stress in liver by a significant increase in the level of MDA (7.6 ± 0.21 nmol/mg) as well as a decrease in the contents of TAC (1.75 ± 0.14 µmol/g), GSH (1.9 ± 0.22 µmol/g) and GST) 3.2 ± 0.28 U/mg). RA treatment decreased MDA (4.32 ± 0.35 nmol/mg) but increased the contents of TAC (3.51 ± 0.34 µmol/g), GSH (3.42 ± 0.16 µmol/g) and GST (5.71 ± 0.71 µmol/g) in APAP group. RA 100 mg/kg decreased ALT (91.5 ± 1.5 U/L), AST (169 ± 8.8 U/L) and CYP450 (3 ± 0.2 nmol/min/mg) in APAP group. Histologically RA attenuated hepatic damage by decreasing necrosis, inflammation, and haemorrhage in liver sections of APAP group. DISCUSSION AND CONCLUSIONS: This is the first report that oral administration of RA dose-dependently elicited significant hepatoprotective effects in rats through inhibition of hepatic CYP2E1 activity and lipid peroxidation. RA-protected hepatic GSH and GST reserves and total tissue antioxidant capacity.

Fatty acid amide hydrolase inhibitor URB597 prevented tolerance and cognitive deficits induced by chronic morphine administration in rats.

Inhibitors of the endocannabinoid metabolic enzyme fatty acid amide hydrolase exert therapeutic effects, but might also be associated with some of the adverse effects of cannabis. However, at least one fatty acid amide hydrolase inhibitor, URB597, has beneficial effects without signs of abuse or dependence. Although previous investigations have evaluated URB597-morphine interactions, the effects of URB597 on morphine tolerance and cognition deficits have not been studied previously. Rats were rendered tolerant to or dependent on morphine by an injection of morphine (10 mg/kg, subcutaneous) twice daily, respectively, for 7 or 10 days. URB597 (1 mg/kg, intraperitoneal) was administered before morphine. The tail-flick and passive avoidance learning tests were used to evaluate tolerance and cognition. Chronic morphine injection led to significant tolerance to the antinociceptive effect on days 5 and 7. URB597 completely prevented the development of morphine tolerance. URB597 also enhanced memory acquisition in the passive avoidance learning test, and although morphine impaired memory, URB597 alleviated this effect. These data show that URB597 protects against tolerance and memory deficits in chronic usage of morphine and suggests URB597 as a promising candidate for the treatment of adverse effects of opioids.

Bioactive peptide carnosin protects against lead acetate-induced hepatotoxicity by abrogation of oxidative stress in rats.

Context Oxidative stress is a common mechanism of liver injury. Carnosine is a dipeptide having strong antioxidant effects. Objectives We investigated the effects of carnosine on lead-induced hepatotoxicity and oxidative stress in rats. Materials and methods Animals received an aqueous solution of lead acetate (500 mg Pb/L in the drinking water) and/or daily oral gavage of carnosine (10 mg/kg) for 8 weeks. Rats were then weighed and used for the biochemical (commercial kits), molecular (standard chemical methods) and histological (microscopic) evaluations. Results Lead-induced oxidative stress in liver tissue was indicated by a significant increase in the level of malondialdehyde (MDA) (8.25 ± 0.15 nmol/mg) as well as decrease in the level of total antioxidant capacity (TAC) (1.72 ± 0.25 µmol/g) and total thiol (SH) groups) 1.9 ± 0.22 µmol/g). Carnosine treatment decreased MDA (4 ± 0.08 nmol/mg), whereas it increased the contents of total thiol (3.25 ± 0.04 µmol/g) and TAC (3.44 ± 0.32 µmol/g) in the lead group. Carnosine also prevented the decreased body weight (p < 0.001), albumin (p < 0.05) and total protein levels (p < 0.001) and increased liver weight (p < 0.05) and activates of hepatic enzymes (p's < 0.001) (alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and lactate dehydrogenase) in the lead group. Furthermore, histopathological study showed that carnosine attenuates liver damage by decreasing necrosis and infiltration of inflammatory cells. Conclusion Carnosine prevented lead-induced hepatotoxicity, indicated by molecular, biochemical and histopathological analyses through inhibiting lipid peroxidation and enhancing antioxidant defence systems. Therefore, carnosine makes a good candidate to protect against the deleterious effect of chronic lead intoxication.

Salvia officinalis L. attenuates morphine analgesic tolerance and dependence in rats: possible analgesic and sedative mechanisms.

BACKGROUND: Salvia officinalis L. (SO) has effects on the central nervous system, including anti-addiction properties that may involve an opioid mechanism. OBJECTIVE: Effects of a hydroalcoholic extract of SO on nociception and on morphine-induced tolerance and dependence were evaluated in rats. METHODS: Tolerance and dependence were induced by injection of morphine (10 mg/kg, s.c.) or escalating doses of morphine (2.5, 2.5, 5, 10, 20, 40 and 50 mg/kg, s.c.) twice daily for 7 days. SO (400, 600 and 800 mg/kg, i.g.) was administered before morphine. The tail-flick and naloxone precipitation withdrawal tests were used to evaluate tolerance and dependence. Sedative effects as well as total polyphenolic and flavonoid were also measured. RESULTS: The morphine-treated group showed significant decrements in the percentage maximum possible effect (%MPE) on days 5 and 7 compared to the first day, illustrating morphine tolerance. Higher doses decreased morphine tolerance. Furthermore, SO (600 and 800 mg/kg) attenuated almost all of the withdrawal signs including weight loss, jumping, penis licking, teeth chattering, wet dog shakes, rearing, standing, sniffing, face grooming and paw tremor and increased sleep duration (64.5 ± 9.7, 100.3 ± 4.7, respectively). Total polyphenolic and flavonoid content of SO was 138 and 69 mg per g of dried extract, respectively. CONCLUSION: SO has antinociceptive effects and may decrease tolerance and dependence induced by repeated morphine administration. However, to determine whether treatment with SO blocks tolerance by interfering with neurobiological mechanisms that mediate the development of morphine tolerance will require further studies.

Antinociceptive and antihyperglycemic effects of Melissa officinalis essential oil in an experimental model of diabetes.

OBJECTIVE: The efficacy of oral administration of Melissa officinalis essential oil (MOEO) on hyperalgesia was investigated using the formalin test in streptozotocin (STZ)-induced diabetic rats. MATERIALS AND METHODS: Animals were divided into control, MOEO-treated control (0.01, 0.02 and 0.04 mg/day), diabetic and MOEO-treated diabetic (0.01, 0.02 and 0.04 mg/day) groups. Nociceptive testing was performed on male adult Wistar rats 4 weeks after the onset of hyperglycemia. At the end of the experiment, all rats were weighed and plasma glucose measurements were performed. RESULTS: Diabetes was associated with significant hyperalgesia during both phases of the formalin test. MOEO (0.04 mg/day) completely reversed hyperalgesia in diabetic rats, while MOEO (0.02 and 0.04 mg/day) caused less intensive nociceptive behaviors during both phases of the test in control rats. MOEO at both high doses restored euglycemia and reduced the body weight of treated diabetic animals compared to untreated diabetic animals. The 0.01-mg dose of MOEO did not alter pain responses in the control or diabetic groups compared to their respective controls. CONCLUSIONS: This study shows that chronic administration of MOEO displays efficacy in an experimental model of diabetic hyperalgesia. MOEO may therefore show promise as a treatment for painful diabetic neuropathy.

GABAA receptors are involved in the analgesic effects of morphine microinjected into the central nucleus of the amygdala.

The central nucleus of the amygdala (CeA) has an important role in pain perception and analgesia. Opioid and GABAA receptors, which are both involved in pain modulation, are found in high concentration in the CeA. The present study was designed to examine the interaction of opioidergic and GABAergic systems in the CeA during modulation of acute thermal pain. In the present study, different doses of morphine (25, 50 and 100 µg/rat), either alone or after 5 min pretreatment with the selective GABAA receptor agonist muscimol (60 ng/rat) or the selective GABAA receptor antagonist bicuculline (50 ng/rat), were injected bilaterally into the CeA of each rat. Tail-flick latencies (TFL) were measured every 5 min for 60 min. The results revealed that microinjection of morphine into the CeA significantly increased TFL in a dose-dependent manner. Microinjection of bicuculline or muscimol in combination with morphine into the CeA increased and decreased TFL, respectively. It seems that morphine in the CeA facilitates the function of descending inhibitory systems by interacting with the activity of local GABAA receptors.

Effects of rosmarinic acid on an experimental model of painful diabetic neuropathy in rats.

CONTEXT: Diabetic neuropathic (DN) pain is one of the diabetes complications. Rosmarinic acid (RA), a natural phenol antioxidant, shows some biological activities, including anti-inflammatory, analgesic, and anti-diabetic effects. OBJECTIVES: We investigated the efficacy of RA administration (10 and 30 mg/kg) on streptozotocin (STZ)-induced neuropathy in rats. MATERIAL AND METHODS: The animals received saline or RA (10 and 30 mg/kg, p.o.; once daily) for 8 weeks. DN was evaluated by the tail flick (TF) method, formalin test, and tactile allodynia. At the end, all rats were weighed and underwent plasma glucose measurement. RESULTS: There was an increase in licking time during both formalin test phases in diabetic animals (138.5 ± 10.7 and 448.7 ± 2.6 s) that was decreased by RA10 mg/kg (103.5 ± 7.5 and 284.4 ± 19 s) and RA 30 mg/kg (81.8 ± 11 and 192.7 ± 14 s). RA 30 mg/kg caused anti-nociception during the early phase in treated controls (52.1 ± 6 s) than untreated controls (99.4 ± 5.9 s). The TF latency in diabetics (2.9 ± 0.1 s) was increased in RA10 and 30 mg/kg treated diabetics (5.3 ± 0.4 and 6 ± 0.86 s). The paw withdrawal threshold (PWT) of the diabetics (3.6 ± 0.7 g) was increased after RA 10 and 30 mg/kg (13.8 ± 0.3 and 14 ± 0.4 g) treatment. RA did not induce a significant change in body weight and plasma glucose of rats. CONCLUSION: RA showed efficacy in amelioration of some aspects of DN. Therefore, RA makes a good candidate for DN treatment in clinical studies.

Preventive effect of Teucrium polium on learning and memory deficits in diabetic rats.

BACKGROUND: Cognitive impairment occurs in diabetes mellitus. Teucrium polium L. (Lamiaceae) has been used in folk medicine to improve mental performance. Here we hypothesized that chronic treatment with an aqueous extract of Teucrium polium (100, 200 and 400 mg/kg, p.o.) would have an effect on passive avoidance learning (PAL) and memory in control and streptozocin-induced diabetic rats. MATERIAL/METHODS: Treatments were begun at the onset of hyperglycemia, and PAL was assessed 30 days later. A retention test was performed 24 h (hours) after training. After PAL and memory assessment, animals were weighed and blood samples were drawn for plasma glucose measurement. RESULTS: Diabetes caused impairment in acquisition of PAL and retrieval of memory. Teucrium polium treatment (200 and 400 mg/kg) improved learning and memory in control rats and reversed learning and memory deficits in diabetic rats. The 100 mg/kg dose did not affect cognitive function. Teucrium polium treatment partially improved the reduced body weight and hyperglycemia of treated diabetic rats, although the differences were not significant compared to non-treated diabetic rats. CONCLUSIONS: These results show that Teucrium polium prevented the deleterious effects of diabetes on PAL and memory. Antioxidant, anticholinesterase and hypoglycemic effects of Teucrium may be involved in the obtained effects. Therefore, Teucrium polium appears to be a promising candidate for memory improvement in diabetes, but this needs confirmation by future clinical studies.

Evaluation of protective effects of methylene blue on cisplatin-induced nephrotoxicity.

Cisplatin (CP) is used to treat various types of cancer. However, its usage is limited due to nephrotoxicity. This study aims to examine the applicability of methylene blue (MB) against CP-induced kidney injuries. In this study, twenty-eight male rats were divided into four groups. Following administration of a single dose of CP (5 mg/kg), animals received intraperitoneal injections (IP) of MB (4 mg/kg) for seven days. In the final phase of the experiment, serum was collected from rats, with blood urea nitrogen (BUN) and creatinine (Cr) levels measured. Hematoxylin-Eosin (H&E) and Masson's trichrome staining were performed to examine histological changes. Immuno-histological staining was used to evaluate caspase-3 protein expression. The results showed that the MB (4 mg/kg) + CP treated rats underwent a lesser weight loss compared to the CP group (p < 0.05 and p < 0.001, respectively). The kidney weight decreased significantly in the CP + MB group compared to the CP group (p < 0.05 and p < 001, respectively). BUN and Cr levels that were increased significantly in the serum of the CP group (p < 0.001) compared to the control group showed no significant increase in the MB + CP group compared to the control group (p = 0.842 and p = 0.989, respectively). There was a significant decrease in kidney tissue injuries in the CP + MB compared to the CP group (p < 0.001). The glomerular size was recovered in the CP + MB group compared to the CP (p < 0.05). The significant increase in the capsular space of the CP group compared to the control group (p < 0.001) was attenuated in the CP + MB. MB restored the histological alterations in the kidneys. Treatment with 4 mg/kg of MB reduced the expression levels of Caspase-3. In conclusion, this study provides evidence concerning the anti-apoptotic roles of MB in CP-induced kidney damage. In conclusion, MB has a positive impact on kidney function.

Effects of Hypericum perforatum extract on diabetes-induced learning and memory impairment in rats.

Cognitive impairment occurs in diabetes mellitus. Hypericum perforatum has been used in folk medicine to improve mental performance. Here it is hypothesized that chronic treatment with an extract of Hypericum perforatum (6, 12 and 25 mg/kg, p.o.) would have effects on passive avoidance learning (PAL) and memory in control and streptozotocin-induced diabetic rats. Treatments were begun at the onset of hyperglycaemia. PAL was assessed 30 days later. A retention test was done 24 h after training. At the end, the animals were weighed and blood samples were drawn for plasma glucose measurement. Diabetes caused impairment in acquisition and retrieval processes of PAL and memory. Hypericum treatment (12 and 25 mg/kg) improved learning and memory in control rats and reversed learning and memory deficits in diabetic rats. A dose of 6 mg/kg did not affect cognitive function. Hypericum administration did not alter the body weight and plasma glucose levels. Antioxidant properties and cholinergic facilitatory effects of Hypericum may be involved in its nootropic effects. These results show that Hypericum perforatum prevented the deleterious effects of diabetes on PAL and memory. As Hypericum would be free of major side effects compared with other nootropic medications, it may provide a new potential alternative for demented diabetic patients.

Effects of GABAA receptors in nucleus cuneiformis on the cannabinoid antinociception using the formalin test.

RATIONALE: Nucleus cuneiformis (NC), a reticular nucleus of the midbrain, is a part of the descending pain modulatory system and therefore has an important role in pain perception. OBJECTIVES: Considering the abundance of GABAA and cannabinoid receptors in the NC and also the bidirectional roles for GABA in controlling nociception, the present study examined the effects of bilateral intra-NC microinjection of different doses of the GABAA receptor agonist, muscimol, and the GABAA receptor antagonist, bicuculline, on pain modulation using formalin test. We also assessed interaction between canabinergic and GABAergic systems in the NC during this test. METHODS: Rats were exposed to intra-NC microinjection of bicuculline (50,100, and 200 ng/side) or muscimol (60, 120, and 240 ng/side) and then subjected to the formalin test. In another set of experiments, the effects of muscimol (60 ng/side) or bicuculline (50 ng/side) administration 5 min before a cannabinoid receptor agonist WIN 55,212-2 (5, 10, and 20 µg/side) microinjection into NC on the formalin test were evaluated. RESULTS: Microinjection of bicuculline and muscimol into the NC decreased and increased pain responses, respectively, in a dose-dependent manner during both phases of the test. Microinjection of WIN 55,212-2 into the NC significantly reduced pain responses in a dose-dependent manner. Microinjection of bicuculline or muscimol in combination with WIN 55,212-2 into the NC respectively potentiated and attenuated WIN 55,212-2-induced antinociception in the formalin test. CONCLUSIONS: This study shows that GABA in the NC is involved in pain modulation and suggests the existence of a GABAA-mediated inhibitory system in the NC on pain control. Furthermore, it seems that the antinociceptive effect of WIN 55,212-2 in the formalin test is mediated partly by the activity of local GABAA receptors in the NC.