Effect of Gallic acid on dementia type of Alzheimer disease in rats: electrophysiological and histological studies

Introduction: To study the effect of gallic acid [GA] on hippocampal long-term potentiation [LTP] and histological changes in animal model of Alzheimer disease [AD] induced by beta-amyloid [Abeta]

Methods: Sixty-four adult male Wistar rats [300 +/- 20 g] were divided into 8 groups: 1] Control [Cont]; 2] AD; 3] Sham; 4-7] AD+GA [50, 100, and 200 mg/kg for 10 days, orally] or vehicle, 8] Cont+GA100, Abeta [1microg/microL in each site] was infused into hippocampus bilaterally. Changes of amplitude and slope of LTP induced in hippocampal dentate gyrus [DG] were evaluated by high frequency stimulation [HFS] of perforant path [PP]

Results: Data showed that LTP amplitude and area under curve significantly impaired in AD rats [P<0.001], while significantly improved in AD rats treated with GA [P<0.05, P<0.01]

Conclusion: Current findings suggest that GA reduces neural damage and brain amyloid neuropathology and improves cognitive function via free radicals scavenging and inhibiting oligomerization of Abeta but with no effect on healthy rats

Improving Active and Passive Avoidance Memories Deficits due to Permanent Cerebral Ischemia by Pomegranate Seed Extract in Female Rats

Background: This study aimed to evaluate the effect of two weeks oral administration of pomegranate seed extract (PGSE) on active and passive avoidance memories after permanent bilateral common carotid arteries occlusion (2CCAO) to induce permanent cerebral ischemia in adult female rats. Methods: Seventy adult female Wistar rats (250 ± 20 g) were used. Animals were divided randomly into seven groups with 10 in each: 1) Sham-operated; 2) Ischemic; 3–6) Ischemic received PGSE (100, 200, 400 and 800 mg/2mL/kg, orally) for 14 days; 7) Ischemic received vehicle. In order to create 2CCAO, carotid arteries were ligatured and then cut bilaterally. Active and passive avoidance task were measured using criterion condition responses (CCRs) in Y-maze and step-through latency (STL) in two-way shuttle box in all female rats. Results: Both active and passive avoidance memories were significantly impaired in rats after cerebral hypoxia-ischemia (CHI) (P < 0.001). PGSE treatment significantly improved passive and active memory impairments with 2CCAO (P < 0.05, P < 0.01, and P < 0.001). No toxicity was observed even with high-dose PGSE consumption (800 mg/kg, for 14 days). Conclusion: PGSE exhibits therapeutic potential for avoidance memories, which is most likely related at least in part to its antioxidative and free radical scavenging actions.

[Effects of forced exercise on withdrawal syndrome, brain hippocampus neurons count and level of serum corticosterone in morphine addicted male rats]

Addiction to morphine impairs the behavioral and cognitive performances. The aim of the present study was to evaluate the effects of forced exercise [treadmill] on withdrawal signs after morphine deprivation, serum corticostrone level, and hippocampus neurons count in brain hemisphers in rats addicted to morphine. Adult male Wistar rats were divided into five groups with 10 in each: 1] exercised control [C+E], 2] sham exercised control [C+Sh.E], 3] addicted [A], 4] exercised addicted [A+E], and 5] sham-exercised addicted [A+Sh.E]. Withdrawal signs such as number of jumping, teeth chattering, wet-dog shaking, defecation, body scratching, and standingas number of were counted during 30 minutes after naloxone administration. Animals in exercised groups ran on treadmill one hour daily from 9-10 Am in the morning for ten consecutive days. Sham-exercised groups passed same times on turned off treadmill while its shock delivered system was turned on. At the end of experiments serum corticostrone level and hippocampus neurons count were done after decapitation the animals in all groups. The data were analyzed with one-way ANOVA that followed by LSD post hoc test. The differences between groups were accepted as significant with P value less than 0.05. Addiction to morphine increased withdrawal signs and corticostrone secretion significantly and reduced hipocampal neurons in brain, All off which were significant. Forced exercise could inhibit certain withdrawal signs induced by morphine deprivation in addicted rats while could not reverse increased corticostrone level and decreased hippocampus neurons. Despite of useful effects of forced exercise on health conditions and especially cognition during aging, it would cause impair severely some neurobehavioral and hormonal disorders in addicted rats to morphine

Motor disturbances and thalamic electrical power of frequency bands' improve by grape seed extract in animal model of Parkinson's disease

Previous studies showed that grape seed extract [GSE] is an excellent natural substance with potent antioxidant effect and free radical scavenger. This study aimed to evaluate the effect of GSE on motor dysfunctions and thalamic local Electroencephalography [EEG] frequency bands' powers in rats with Parkinson's disease [PD]. In this study 8 micro g 6-hydroxydopamine [6-OHDA] dissolved in 2 micro l normal saline containing 0.01% ascorbic acid was infused into right medial forebrain bundle [MFB] to make an animal model of PD. Rats with PD received four weeks GSE [100 mg/kg, p.o.] after apomorphine-induced rotation test. Spontaneous motor tests and also thalamic ventroanterior nucleus [AV] local EEG recording were done in freely moving rats in all groups. Chronic treatment of PD rats with GSE could influence potentially frequency bands' powers of thalamic VA and improve post-lesion motor dysfunctions significantly [p<0.05 and p<0.01, respectively]. Our findings suggest that GSE modulates the CNS function and has beneficial effects on the direct and indirect striato-thalamo-cortical pathways in PD. GSE acts as a new and potent natural free radical scavenger which removes oxidants produced by neurotoxin 6-OHDA in brain. Therefore, it reinforces electrical power of remained thalamic VA neurons and thereby improves post-lesion motor disorders

Effect of different doses of soy isoflavones on spatial learning and memory in ovariectomized rats

Introduction: Several studies indicate that estrogen use increase performance on some tests of cognition especially in postmenopausal women. These steroids have many side effects, thus, other estrogenic agents with fewer side effects are needed to develop alternative treatment strategies. The main objection of this study was to evaluate the effects of different doses of dietary soy meals [with or without isoflavone] on spatial learning and memory in ovariectomized [OVX] rats. Methods: Female Wistar rats with the exception of intact group were ovariectomized at the first line of study. Subjects were divided into six groups. The control group rats [c] were gonadally intact, while the others were OVX. OVX groups received normal diet [0], treated with 10 gr soy [10], 20 gr soy [20], 10 gr isoflavone free soy [-10] or 20 gr isoflavone free soy [-20] in daily diet for four weeks. The spatial learning and memory were tested using Morris water maze. Rats were trained in water maze to find a hidden escape Platform. Rats received 6 blocks that each block consisted of 3 trials. Following acquisition trials, one probe trial were conducted in which the platform was removed. Results: Soy meal diet [with or without isoflavone] in ovariectomized rats caused improvement of performance across 18 trials of Acquisition. Discussion: Our results suggest that soy consumption apart from containing isoflavone or not is a potential alternative to estrogen in the improvement of cognition

[Preventive effect of grapefruit juice [Citrus Paradisi Macf.] on morphine withdrawal symptom in male rats]

Addiction to opiates such as morphine is one of major public health problems. It has been shown that in addicted animals, administration of antioxidant agents such as vitamin C can reduce the withdrawal symptoms [WDS]. The aim of this study was to evaluate the preventional effect of grapefruit juice [Citrus Paradisi Macf.] on withdrawal symptoms in rats. In this experimental study, Sixteen male Wistar rats [250-300g] randomly divided into two groups [n=8]. All animals were addicted by intraperitoneal [i.p] injection of morphine [the 1-3 days: 10 mg/kg, the 4-6 days: 20 mg/kg and the 7-9 days 40 mg/kg; daily] for 9 days. The first group received 2 ml Citrus Paradisi Macf. orally 1 hour before morphine administration. The sham group received 2 ml of normal saline. Naloxone [10mg/kg, s.c] was administrated 45 minutes after of an additional dose of morphine [40 mg/kg] in the tenth day for withdrawal symptoms inducing. Then withdrawal symptoms such as frequency of wet-dog shaking, teeth chattering, defecation and penis licking were evaluated for 30 minutes. All withdrawal symptoms including frequency of wet-dog shaking, teeth chattering, defecation and penis licking were reduced in the Citrus Paradisi Macf. group in comparison with the sham group significantly [p < 0.05]. Our results showed that presumably antioxidant activity of Citrus Paradisi Macf. can reduce withdrawal symptoms. Although the exact mechanisms of its effect in brain need to be elucidate