Protective effect of Centella asiatica against D-galactose and aluminium chloride induced rats: behavioral and ultrastructural approaches

Background: Alzheimer’s disease (AD) is a neurodegenerative disorder and the commonest cause of dementia among the aged people. D-galactose (D-gal) is a senescence agent, while aluminium is a known neurotoxin linked to pathogenesis of AD. The combined administration of rats with d-gal and aluminium chloride (AlCl3) is considered to be an easy and a cheap method to obtain an animal model of AD. The plant Centella asiatica (CA) is reported to exert neuroprotective effects both in vitro and in vivo. Therefore, this study explored the protective effects of CA on cognition and brain ultrastructure in d-gal and AlCl3 induced rats. Materials and methods: Rats were exposed to d-gal 60 mg/kg/b.wt/day + AlCl3 200 mg/kg/b.wt/day and CA (200, 400 and 800 mg/kg/b.wt/day) and 1 mg/kg/b.wt/day of donepezil for 70 days. Different cognitive paradigms viz. T maze spontaneous alternation, modified elevated plus maze and novel object recognition test, were used to evaluate full lesions of the hippocampus, spatial learning and memory and non-spatial learning and memory respectively. Nissl’s staining was used to determine the survival of hippocampus CA1 pyramidal cells, while transmission electron microscopy was used to check the ultrastructural changes. Results: The results revealed that d-gal and AlCl3 could significantly impair behavior and cognitive functions, besides causing damage to the hippocampal CA1 pyramidal neurons in rats. In addition, it also caused ultrastructural morphological alterations in rat hippocampus. Conversely, co-administration o;f CA, irrespective of the dosage used, alleviated the cognitive impairments and pathological changes in the rats comparable to donepezil. Conclusion: In conclusion the results suggest that CA could protect cognitive impairments and morphological alterations caused by d-gal and AlCl3 toxicity in rats. Biochemical and molecular studies are ongoing to elucidate the probable pharmacodynamics of CA

Emerging evidence for the modulation of exocytosis by signalling lipids

Membrane fusion is a key event in exocytosis of neurotransmitters and hormones stored in intracellular vesicles. In this process, soluble N-ethylmaleimide sensitive factor attachment protein receptor (SNARE) proteins are essential components of the exocytotic molecular machinery, while lipids have been seen traditionally as structural elements. However, the so-called signalling lipids, such as sphingosine and arachidonic acid, interact with SNAREs and directly modulate the frequency and mode of fusion events. Interestingly, recent work has proved that the sphingosine analogue FTY-720, used in the treatment of multiple sclerosis, mimics the effects of signalling lipids. In the present Review, we discuss recent investigations suggesting that endogenous signalling lipids and synthetic analogues can modulate important physiological aspects of secretion, such as quantal release, vesicle recruitment into active sites, vesicle transport and even organelle fusion in the cytosol. Therefore, these compounds are far from being merely structural components of cellular membranes

Effect of long term administration of tamoxifen on memory in male rat

Background and Objective: Tamoxifen is one of the selective estrogen receptor modulators that exerts estrogen / anti-estrogen effects in various tissues. This study was done to evaluate the effect of chronic administration of tamoxifen on spatial memory and passive avoidance task in adult male Wistar rats. Methods: In this experimental study, 48 adult male Wistar rats were randomly divided into control, sham and tamoxifen groups. Animals in sham and tamoxifen groups were received tamoxifen solution and tamoxifen (400mg/kg/day) orally for 35 consecutive days. At the end of treatment, spatial learning and memory of animals was assessed using the Morris water maze task and passive avoidance memory was examined using the shuttle box. Results: The time spent and distance moved to reach the platform, significantly increased in tamoxifen group compared to controls (P<0.05). In addition, the time spent and distance moved in the target quadrant (in the probe test) significantly reduced in tamoxifen group in compared to controls (P<0.05). In passive avoidance task, tamoxifen significantly decreased the time of the entrance to the dark room compared to control animals (P<0.05). Conclusion: Long-term administration of tamoxifen impairs spatial learning and memory and passive avoidance memory in rats

Effect of Myrtus Communis Hydro-Alcoholic Extract on Chronic Restraint Stress-Induced Spatial Memory Deficit in Adult Male Rats

Background and Aim: Chronic restraint stress impairs spatial learning and memory. Myrtle (Myrtus communis) has antioxidant, antidiabetic, hepatoprotective and neuroprotective properties. The aim of this study was to investigate the effect of myrtle hydroalcoholic extract on chronic restraint stress-induced spatial learning and memory deficit in adult male Wistar rats. Materials and Methods: In this experimental study, 80 adult male Wistar rats were allocated to eight groups (10 in each) included control group (intact), myrtle0.75, myrtle1.5, myrtle3 groups (were gavaged with hydroalcoholic extract of myrtle at 0.75, 1.5 and 3 mg/ kg bw doses), stress group (restrained in restrainers for 6 hours per day for 21 consecutive days), stress- myrtle0.75, stress-myrtle1.5 and stress- myrtle3 groups (received myrtle extract at 0.75, 1.5 and 3 mg/ kg bw doses and exposed to chronic immobility stress). Spatial learning and memory were examined through the Morris water maze test. Findings: Chronic immobilization stress caused spatial learning and memory impairment. Consuming doses 1.5 and 3 of Myrtle extract to stressed animals caused significant decrease in spent time and swam distance to reach the hidden platform (p<0.05) and increased time lapsed in target quadrant comparing with stress group (p<0.05). Conclusion: It has been concluded that myrtle extract can improve spatial learning and memory in rats exposed to stress in a dose dependent manner

Anxiolytic and antidepressant effects of Basil (Ocimum basilicum L.) hydro-alcoholic extract in male rats exposed to chronic restraint stress

Introduction: Studies show that chronic stress can lead to anxiety and depression. Basil (Ocimum basilicum&nbsp;L.) has antioxidant, anti-inflammatory, anti-apoptotic, anti-diabetic and anti-nociceptive properties. The aim of this study was to investigate the effect of basil hydro-alcoholic extract on chronic restraint stress-induced anxiety and depression in male Wistar rats. Methods: In this experimental study, 48 rats were allocated to 6 groups including: Control, Basil200 and Basil400 (receiving doses 200, 400 mg/kg/bw of Basil extract during 21 days), Stress (restrained in restrainers for 6hours per day for 21 consecutive days), Stress-Basil200 and Stress-Basil400 (received Basil extract in addition to chronic immobility stress). At the end of this period, anxiety and depression were evaluated using elevated plus maze (EPM) and forced swimming test, respectively. Results: Results show that chronic immobility causes anxiety and depression like behaviors in rats. Taking both doses of the Basil extract led to significant increase in percentages of open arm entry and time spent in open arm in EPM test compared with Stress Group (P<0.05). The results of forced swimming test showed significant increase in latency time (p<0.05) and decrease in immobility time (p<0.05) in Stress-Basil groups compared with Stress group. Conclusion: It is concluded that the Basil hydro-alcoholic extract, reduced anxiety and depression like behaviors in rats exposed to chronic restraint stress

Anxiolytic and antidepressant effects of tarragon (Artemisia dracunculus L.) hydro-alcoholic extract in male rats exposed to chronic restraint stress

Tarragon (Artemisia dracunculus L.) has antioxidant, anti-diabetic, anti-bacterial and anti-inflammatory proper-ties. The aim of this study was to evaluate the effect of tarragon hydro-alcoholic extract on anxiety and depression in male rats exposed to chronic restraint stress. Forty eight male rats were randomly divided into six groups including 1) control, 2) stress, 3) tarragon 100, 4) tarragon 500, 5) stress-tarragon 100 and 6) stress-tarragon 500. Groups 2, 5, and 6 were placed in restrainer for 21 consecutive days, 6 hours a day. Groups 3, 4, 5, and 6 were gavaged with tarragon extract of different do-ses (100 and 500mg/kg). At the end of this 21-day period, anxiety and depression were evaluated by elevated plus maze and forced swimming test. Data analysis was performed using one-way ANOVA, p<0.05 being considered significant. The pe-rcentages of open arm entry and time spent in open arm increased significantly in tarragon-stress groups compared with st-ress group (p<0.05). Tarragon extract decreased significantly the immobility time in rats exposed to stress in forced swim-ming test (p<0.01). The results suggested that hydro-alcoholic extract of Artemisia dracunculus L. reduced the anxiety and depression in rats exposed to chronic immobilization stress, probably due to its anti-oxidant compound

Effect of Royal Jelly on Blood Glucose and Lipids in Streptozotocin Induced Type 1 Diabetic Rats

Abstract Background: Diabetes is the most common endocrine disorder that leads to hyperglycemia and hyperlipidemia. Royal jelly is as a bee-collected natural product has diverse biological properties and that is rich in natural antioxidants. The aim of this study was to investigate the effects of royal jelly on serum glucose and lipids profile in streptozotocin induced type 1 diabetic rats. Materials and Methods: In this experimental study, 40male Wistar rats were divided into 5 groups(8 in each): control, diabetic rats, Glibenclamide, and two groups of royal jelly- treated diabetic. Diabetes was induced in the rats by injection of streptozotocin (60 mg/kg b.w) intraperitoneally. The royal jelly was gavaged at doses of 100 and 200 mg/kg after streptozotocin injection for30 days. At the end of this period, levels of glucose, cholesterol, triglyceride, LDL and HDL in serum were measured. Results: Royal jelly and Glibenclamide significantly decreased the levels of glucose, cholesterol, triglyceride and LDL in diabetic rats (p<0.01). In addition, significant increase (p<0.01) in HDL level was observed in royal jelly-treating rats in comparison to the diabetic rats. Conclusion: The results indicated that royal jelly may be used effectively in controlling and attenuating the complications of diabetes. The hypoglycemic and hypolipidemic effects of royal jelly may be due to the presence of antioxidants