Postnatal dietary supplementation with either gangliosides or choline: effects on spatial short-term memory in artificially-reared rats

This study addressed the hypothesis that dietary supplementation with either gangliosides or choline during the brain growth spurt would enhance short-term spatial memory. Male Long-Evans rats were reared artificially from postnatal days (PD) 5-18 and were fed diets containing either (i) choline chloride 1250 mg/l (CHL), (ii) choline chloride 250 mg/l and GD3 24 mg/l (GNG) or (iii) choline chloride 250 mg/l (STD). A fourth group (SCK) was reared normally. Rats were weaned onto AIN 93G diet and on PD 35 were trained on a cued delayed- matching-to-place version of the Morris water maze. All groups learned to swim to the beacon that indicated the platform position on the first trial; similarly, on the second un-cued trial, the distance swam to reach the platform decreased to the same extent in all groups over the five days of training. The groups also responded in the same way to an increase in delay between the first and second trial from 1 min to 1 h, showing an increase in the distance swam, accompanied by a decrease in the number of direct swims to the platform. Thus, all rats were equally proficient at using spatial short-term memory, regardless of the choline or ganglioside content of the preweaning diet.     

Chronic administration of UMP ameliorates the impairment of hippocampal-dependent memory in impoverished rats

We have previously shown that chronic, but not acute, dietary supplementation with CDP-choline prevents the hippocampal-dependent memory deficits manifested by aged rats and by rats reared under impoverished environmental conditions. In rats, dietary CDP-choline is rapidly metabolized into cytidine and choline; the cytidine is then readily converted to uridine, which enters the brain and, via conversion to UTP and CTP, increases brain levels of membrane phosphatides. Hence, we have assessed whether administering a uridine source (UMP) instead of CDP-choline can also ameliorate the memory deficits in rats reared under impoverished environmental conditions. At weaning, 32 male Sprague-Dawley rats were exposed to either enriched (EC) or impoverished (IC) conditions for 3 mo. Concurrently, IC and EC rats were given access to either a control diet or a diet supplemented with 0.1% UMP. Rats were then assessed for learning and memory skills using 2 versions of the Morris water maze, the hidden platform version that assesses hippocampal-dependent cognitive memory processing, and the visible platform version that assesses striatal-dependent habit memory. As expected, exposure to the impoverished environment impaired hippocampal-dependent, but not striatal-dependent learning and memory. Supplementation with UMP prevented this cognitive dysfunction, as had been observed with supplemental CDP-choline. These results suggest that IC rats do not use and/or remember their spatial strategies for task solving as well as EC rats, and that long-term dietary supplementation with UMP alleviates this dysfunction.     

Dietary choline requirements of juvenile hybrid tilapia, Oreochromis niloticus x O. aureus

An 8-wk feeding trial was conducted to determine the dietary choline requirement for juvenile hybrid tilapia, Oreochromis niloticus x O. aureus. Purified basal diets were formulated using vitamin-free casein (contained 370 mg choline/kg) as the protein source. Graded levels (0, 100, 200, 400, 600, 800, 1,000 and 2,000 mg choline/kg diet) of choline chloride were added to the basal diet, resulting in eight dietary treatments in the experiment. Each diet was fed to three replicate groups of tilapia initially averaging 0.62 +/- 0.01 g/fish in a closed, recirculating rearing system. Feed efficiency, survival and blood triglyceride, cholesterol and phospholipid concentrations were generally high in fish fed choline-supplemented diets compared to fish fed the control diet. Analysis by broken-line regression of weight gain and body choline concentration and by polynomial regression of liver lipid concentration of the fish indicated that the dietary choline concentration for tilapia is about 900 mg/kg. Taking into account the choline concentration of the unsupplemented basal diet, the optimal dietary choline requirement for growing tilapia is about 1,000 mg/kg.     

Effects of Dietary n-3 Fatty Acid Deficiency on Morris Water-Maze Performance and Amphetamine-Induced Conditioned Place Preference in Rats

In these studies we examined whether dietary n-3 fatty acid (FA) deficiency in adult male rats was associated with effects on performance in the Morris water-maze and with the development of a conditioned place preference to low (0.5 mg/kg) and high (2.0 mg/kg) doses of amphetamine. The male rats used in these studies had been raised for two generations on n-3 deficient diets, which produced an n-6: n-3 FA ratio in brain lipids three times that of animals fed an n-3 adequate diet. Although the two groups did not differ on learning the position of the hidden platform in the Morris water-maze, the n-3 deficient rats did show deficits on a subsequent working memory version of this task, and swam longer distances to reach a visible platform. There were no differences between the groups on the development of a conditioned place preference although, during the initial conditioning cycle, the increase in activity in response to the high dose of amphetamine was apparent only in the n-3 deficient group. These findings provide preliminary support for effects of n-3 FA deficiency on working memory, but not on motivational processes as measured by response to a drug reward.     

双酚A及高脂饮食对成年大鼠空间记忆和情绪的影响

目的观察双酚A(bisphenol A,BPA)和高脂饮食(high-fat diet,HFD)慢性暴露对成年大鼠空间记忆和情绪的综合影响。方法将36只30日龄清洁级雄性Wistar大鼠随机分为4组,分别为对照(普通饲料)组、BPA(50μg/kg)组、HFD组和HFD+BPA(50μg/kg)组,每组9只。采用自由摄食方式进行染毒,连续染毒20周。分别进行Morris水迷宫试验和旷场试验。结果与对照组比较,HFD和(或)BPA组大鼠的潜伏期均延长,除第2天BPA组和第3天HFD组外,差异均有统计学意义(P0.01)。与BPA组比较,仅第2天HFD+BPA组大鼠的潜伏期延长,差异有统计学意义(P0.01)。与对照组比较,第1、2天BPA组及第3~5天HFD和(或)BPA组大鼠的游泳速度均减慢,差异均有统计学意义(P0.01)。与BPA组比较,仅第5天HFD+BPA组大鼠的游泳速度减慢,差异有统计学意义(P0.01)。与对照组相比,HFD和(或)BPA组大鼠的目标象限游泳时间和中央区停留时间均缩短,差异均有统计学意义(P0.01);而跨格子总数均无明显变化。结论双酚A和高脂饮食均可以诱发成年大鼠的空间记忆损害和焦虑行为,但其彼此无相互作用。     

Scopolamine does not differentially affect Morris maze performance in adult rats exposed prenatally to alcohol

Rats exposed prenatally to alcohol have shown deficits in spatial learning in radial-arm and Morris mazes. Prenatal exposure to alcohol in rats has also been shown to alter central nervous system (CNS) cholinergic function. Since cholinergic dysfunction disrupts spatial learning in normal rats, the present experiment assessed the role of putative prenatal alcohol-induced cholinergic dysfunction in spatial learning in rats. Pregnant rats were fed alcohol via liquid diet from gestation day 6 to 20. Control dams were pair-fed liquid diet without alcohol or fed ad lib lab chow and water. Group housed adult male and female offspring (postnatal days 110 to 135) were given scopolamine-HCl (o, 0.5, or 1.0 mg/kg/day) and tested in a Morris maze, with four trials per day for four days. A 15-s probe trial preceded testing on days 2–4. On day 5, the rats were given four trials to learn a new platform location. Scopolamine produced dose-dependent increases in latency to find the platform for all groups. There were no significant differences among prenatal treatment groups in scopolamine-induced shifts in performance. The results did not support the hypothesis that prenatal alcohol-induced CNS cholinergic dysfunction is related to spatial learning performance in these rats.     

Effects of maternal mild zinc deficiency and zinc supplementation in offspring on spatial memory and hippocampal neuronal ultrastructural changes

ObjectiveKnowledge about the hippocampal morphologic mechanisms of learning and memory for maternal mild zinc deficiency during pregnancy/lactation followed by zinc supplementation of pups after weaning is limited. This study examined the effects of zinc deficiency and zinc supplementation on cognition and hippocampal neurons.MethodsOne-day pregnant rats were randomly divided into four groups (n = 12): control (CO), pair-fed (PF), zinc-deprived (ZD), and oral zinc-supplemented (OZS). The CO and PF groups were fed a control diet (zinc 25 μg/g diet), and the others were fed a mildly zinc-deficient diet (zinc 2 μg/g diet) during pregnancy and lactation. After weaning (day 21), offspring in the OZS group were switched to a control diet. After 35 d, the behavioral function of the offspring was tested with the Morris water maze test. The ultrastructure of the hippocampal CA3 area was observed under a transmission electron microscope.ResultsCompared with the CO and PF groups, rats in the ZD group spent more time finding the latent platform and swam longer distances (P < 0.05). The time used finding the platform and the swimming distance in the OZS group were similar to those in the CO and PF groups (P > 0.05). In addition, apoptotic neuronal changes in the hippocampus were observed in the ZD group, whereas the reversal of neuronal morphologic changes was observed in the OZS group.ConclusionThe changes in hippocampal neuron morphology were consistent with the changes in the learning and memory ability of mildly zinc-deficient and zinc-supplemented offspring.     

Postnatal Choline Supplementation Rescues Deficits in Synaptic Plasticity Following Prenatal Ethanol Exposure

Prenatal ethanol exposure (PNEE) is a leading cause of neurodevelopmental impairments, yet treatments for individuals with PNEE are limited. Importantly, postnatal supplementation with the essential nutrient choline can attenuate some adverse effects of PNEE on cognitive development; however, the mechanisms of action for choline supplementation remain unclear. This study used an animal model to determine if choline supplementation could restore hippocampal synaptic plasticity that is normally impaired by prenatal alcohol. Throughout gestation, pregnant Sprague Dawley rats were fed an ethanol liquid diet (35.5% ethanol-derived calories). Offspring were injected with choline chloride (100 mg/kg/day) from postnatal days (PD) 10–30, and then used for in vitro electrophysiology experiments as juveniles (PD 31–35). High-frequency conditioning stimuli were used to induce long-term potentiation (LTP) in the medial perforant path input to the dentate gyrus of the hippocampus. PNEE altered synaptic transmission in female offspring by increasing excitability, an effect that was mitigated with choline supplementation. In contrast, PNEE juvenile males had decreased LTP compared to controls, and this was rescued by choline supplementation. These data demonstrate sex-specific changes in plasticity following PNEE, and provide evidence that choline-related improvements in cognitive functioning may be due to its positive impact on hippocampal synaptic physiology.     

人参茎叶皂甙和胆碱合用对学习记忆的影响

目的　观察人参茎叶皂甙和胆碱合用对学习记忆的影响。方法　应用一次性训练被动回避跳台实验和水迷宫空间分辨能力测试实验 ,利用东莨菪碱致大鼠学习记忆障碍模型、致小鼠学习障碍和记忆获得障碍模型、亚硝酸钠致小鼠记忆巩固障碍模型、乙醇致小鼠记忆再现障碍模型。结果　人参茎叶皂甙 (40 0 mg/kg bw,灌服 )和胆碱 (2 0 0 mg/kg bw,灌服 )合用 ,在跳台和水迷宫实验中 ,显著改善东莨菪碱所致大鼠学习记忆障碍 ;在跳台实验中 ,显著改善小鼠学习障碍、记忆获得障碍、记忆巩固障碍和记忆再现障碍 ,比单用人参茎叶皂甙或胆碱效果明显 ,合用后 Q>1。结论　人参茎叶皂甙和胆碱合用有协同增强学习的作用     

Lieber-decarli alcohol diet modification to enhance growth in young rats

When male Sprague Dawley rats weighing ca 160 g were fed theLieber-DeCarli alcohol diet for 3 weeks, their growth rate was 3.8± 0.6 g/day. When the diet was supplemented with calcium phosphate (2.92 g/l), manangese carbonate (20.4 mg/l), ferric citrate (35 mg/l), zinc carbonate (9.3 mg/l), copper carbonate (1.75 mg/l), choline bitartrate (353 mg/l) and pyridoxine hydrochloride (1.2 mg/l), growth increased significantly (4.8±0.8 g/day). The daily weight gain was even greater when rats were fed the Lieber-DeCarli diet having instead of 36%, only 26% calories as alcohol (6.9±1.4 g/day). The amount of diet consumed per day also increased ca 50% as compared to the rats fed the 36% alcohol diet. Thus, the ingestion of more calories and minerals than that by rats fed the Lieber-DeCarli alcohol diet promoted a higher growth rate. Hence, supplementation of the 26% alcohol diet did not exhibit any marked effect on growth. Regardless of feeding the Lieber-DeCarli alcohol diet or its modifications, rats consumed similar amounts of alcohol (22–24 calories) per day. Our observations show that new investigations can now be carried out to examine the effect of chronic alcohol administration under conditions of improved growth in young rats.     

Choline-deficient diet increases Z protein concentration in rat liver

Feeding rats a diet deficient in choline results in fatty liver within 1 d. We studied the effect of short-term (1-3 d) choline deficiency on rat liver Z protein (fatty acid-binding protein). Groups of three females Sprague-Dawley rats were fed ad libitum a purified diet lacking choline and L-methionine or were supplemented with 0.2% choline chloride and 0.82% L-methionine. Animals were killed after 1, 2 or 3 d of consuming control or experimental diets and hepatic Z protein was prepared. Z protein in livers from experimental and control rats were estimated with the fluorescent probe dansylamino undecanoic acid. The corresponding fatty acid-binding activity was also determined. One day of choline-deficient diet increased Z protein concentration threefold, reaching a plateau on the second and third day. Fatty acid-binding activity of Z protein remained unchanged.     

低硒对F344纯系大鼠子代神经行为发育和学习记忆能力的影响

目的建立F344纯系大鼠低硒动物模型,观察低硒对子代仔鼠神经行为发育和空间学习记忆能力的影响。方法以纯系F344大鼠为实验对象,采用人工半合成饲料(低硒组饲料硒含量<0.01mgkg,补硒对照组饲料中硒含量为0.1～0.3mgkg)建立低硒大鼠模型,观测子一代仔鼠哺乳期的生长体重变化、生长发育生理学指标和神经反射指标,并采用开场实验、Morris水迷宫实验检测其行为活动和空间学习记忆能力。结果(1)低硒组大鼠尾血GSHPx活性极其显著地低于对照组(P<0.001)。(2)低硒组仔鼠的出生体重和哺乳期神经发育不同时间点体重明显低于对照组。(3)仔鼠出生后第4天平面翻正和悬崖回避、第10天听觉惊愕反射实验中,低硒组评分均低于对照组(P<0.05),但在第7天平面翻正、悬崖回避和第11天后的听觉惊愕反射实验以及第12、14天前肢悬挂、后肢行走能力实验中,两组仔鼠结果差异无统计学意义(P>0.05)。(4)开场实验中:低硒组雄仔鼠在中央格停留时间、穿行格数较对照组明显减少(P<0.05)。(5)Morris水迷宫实验:①低硒组仔鼠第4、5天的定位航行实验中,平均潜伏期比对照组明显延长(P<0.05);在第6、9时间段的直线式搜索方式也较对照组减少(P<0.05);②低硒组在空间探索实验中,原站台象限活动时间较对照组减少(P<0.05)。结论成功利用纯系F344大鼠建立了低硒动物模型,母代长期硒缺乏导致了子一代F344仔鼠出生体重减低、生后体格发育和神经行为发育的迟缓,雄性仔鼠对新异环境中的适应能力减弱,并且导致了子代仔鼠空间学习和记忆能力能力的减弱。     

Dietary choline requirement of juvenile yellow perch (Perca flavescens)

We conducted an 11-wk feeding trial to determine the dietary choline requirement of juvenile yellow perch (Perca flavescens) and to investigate whether dietary phosphatidylcholine (PC) could meet this requirement. Six dietary treatments contained choline concentrations of <0.11, 0.23, 0.34, 0.75, 1.22 or 3.37 g/kg diet. Two additional diets contained 31 g of lecithin/kg diet, with or without supplemental choline chloride (4.0 g choline/kg diet). The total sulfur amino acid concentration was maintained at 1.0 g/100 g diet (methionine/cyst(e)ine, 49:51). Diets were fed to satiation twice daily to triplicate groups of yellow perch initially weighing 16.0 g/fish. Weight gain, feed intake and carcass proximate composition were significantly affected by dietary choline. Weight gains and feed intakes increased as dietary choline increased from 0 to 0.75 g/kg. Both values tended to plateau in fish fed dietary choline levels above 0.75 g/kg. Broken-line analyses of weight gain and feed intake data indicated the dietary choline requirement was 0.598 and 0.634 g/kg diet, respectively. Hepatic lipid concentrations and feed efficiency values were not significantly different. Whole-body fat concentrations increased significantly, whereas ash levels decreased significantly in fish fed increasing levels of dietary choline. Weight gain and feed intake of fish fed diets containing PC were not significantly different from fish fed 0.75 g/kg of dietary choline. However, hepatic lipid concentrations were significantly higher in fish fed the diet containing PC and no choline chloride. Thus, yellow perch require a maximum of 0.598-0.634 g of choline/kg diet for maximum growth and this requirement may potentially be met with 31 g of lecithin/kg diet.     

Intermittent binge alcohol exposure during the periadolescent period induces spatial working memory deficits in young adult rats

Human and animal studies suggest adolescence is a period of heightened sensitivity to adverse cognitive sequelae of alcohol exposure. The present study assessed the effects of intermittent binge ethanol intoxication during the periadolescent period of Wistar rats on subsequent performance in a Morris water maze spatial navigation task. On postnatal days 32-56, rats were exposed to ethanol or air 3 days/week via vapor inhalation chambers. Acquisition of spatial navigation was assessed beginning 5 days after the final day of exposure, with 3 days of training in the Morris Water maze (four trials per day spaced at 90-s intertrial intervals [ITIs]). Rats were placed into the water maze at one of four positions along the perimeter, with a different release position to begin each trial. A probe trial assessed retention of platform location on the day after the final set of training trials. Four days after this probe trial, rats entered a working memory phase in which the platform was in a new location each day and a variable ITI of 1, 2, or 4h was inserted between Trials 1 and 2; Trials 3 and 4 followed at 90-s intervals after Trial 2 on each day. The "savings" in latency to find the platform and distance traveled before finding it from Trial 1 to Trial 2 on each day served as an index of working memory. Ethanol-exposed rats showed similar acquisition of spatial navigation as control rats during training, as well as similar retention of platform location during the probe trial. However, rats exposed to average blood alcohol level (BAL) >200mg% showed accelerated forgetting, with decreased retention of platform location at the 2-h ITI (P<.05), compared to control rats. Therefore, a 4-week history of intermittent ethanol exposure at BAL in excess of 200mg% during periadolescence led to a working memory deficit in young adult rats, demonstrated by accelerated forgetting of novel information. These behavioral data are consistent with findings from adolescent human studies, indicating that binge-style alcohol exposure during the periadolescent stage of development is associated with deficits in retention of information.     

叶酸缺乏与学习记忆及海马突触体膜流动性相关性研究

目的 :　探索叶酸缺乏对离乳大鼠学习记忆能力与海马突触体膜流动性的影响。方法 :　 5 4只刚离乳的健康雄性 SD大鼠 ,随机分成三组 :实验组 (FD)、对饲组 (PF)和对照组 (AL)。实验组饲去叶酸的 RHAA配方饲料 ,另二组饲以添加叶酸 8mg/ kg的 RHAA饲料 ,对饲组按实验组的进食量加以控制 ,对照组不控制进食。分别于饲养第 2和第 6 w末测定血清叶酸 (SFA)浓度和进行 Morris水迷宫测试大鼠的学习记忆能力 ,记录平均逃避潜伏期和分析原平台象限游泳距离占游泳总距离的百分比 ,分离海马突触体 ,透射电镜作形态学证实 ,用荧光物质 DPH标记突触体后测定荧光强度 ,后者反映突触体膜流动性。结果 :　实验第 2 w FD血清叶酸浓度降低 (P<0 .0 1 )。FD及 PF第 6 w时 SFA浓度明显低于 AL和 PF(P<0 .0 1 ) ,平均逃避潜伏期明显延长 ,原平台象限游泳距离百分比及海马组织突触体膜流动性均明显下降。与对照组比较 ,对饲组上述指标的改变不明显 (P>0 .0 5 )。相关分析结果 :海马结构分离突触体膜 r值与血清叶酸浓度、平均逃避潜伏期及原平台象限游泳距离百分比显著相关 (r=- 0 .5 2 7,P<0 .0 5 ;r=- 0 .45 1 ,P<0 .0 5 ;r=- 0 .5 79,P<0 .0 5 )。结论 :　 1 .叶酸缺乏可损害离乳大鼠的空间学习记忆能力和降低海马突触体膜?     

朱砂与氯化汞、硫化汞神经及肾毒性的比较研究

[目的]比较氯化汞、硫化汞以及朱砂对大鼠学习记忆行为以及肾脏功能的影响,探讨朱砂与其他两种汞化合物在引起神经毒性以及肾毒性方面的异同. [方法]连续30 d经口灌胃给予大鼠氯化汞(0.2 mg/kg;1 mg/kg;5 mg/kg)、硫化汞(10 mg/kg; 100 mg/kg;1 000 mg/kg)和朱砂(10 mg/kg; 100 mg/kg;1 000 mg/kg),通过Morris水迷宫以及穿梭箱实验观察大鼠空间以及事件性学习记忆行为的变化,同时通过测定血清肌酐以及尿素氮观察肾脏功能的变化. [结果]大鼠连续30 d经口摄入1 000 mg/kg的朱砂影响大鼠事件性学习记忆行为,表现为主动回避次数减少(P＜0.05),被电击次数以及逃避潜伏期显著增加(P＜0.05),但氯化汞和硫化汞各剂量均朱观察到显著的改变.氯化汞5 mg/kg组由于影响蛋白质代谢而使血清肌酐和尿素氮有明显降低,朱砂和硫化汞诱导的肾损伤标志物的变化与氯化汞类似.[结论]朱砂可以导致大鼠事件性学习记忆行为改变,其肾脏毒性可能与氯化汞具有类似机制.3种形式的汞化合物均没有影响大鼠的空间性记忆.     

Supplementation with L-histidine during dietary zinc repletion improves short-term memory in zinc-restricted young adult male rats

Zinc, an essential dietary element, modulates neurotransmission in brain regions associated with cognition. Cognitive dysfunction has been reported in offspring of female rats fed zinc-restricted diets during gestation and/or lactation. Studies on the cognitive effects of zinc restriction during young adulthood are limited. After a 3-wk period of dietary zinc restriction, male rats (71-75 d old) were repleted with zinc chloride alone, or zinc chloride supplemented with L-histidine, and short-term memory was measured using the Morris water maze. During restriction, zinc-restricted rats demonstrated significantly longer (86.0%) retrieval latencies than nonrestricted controls, and significantly lower liver (25.5%), bone (32.5%) and hippocampal (3.2%) zinc concentrations. During subsequent repletion, rats repleted with zinc chloride supplemented with L-histidine improved their retrieval latencies to the extent that they were no longer significantly different from controls by repletion d 3. This was associated with a return of hippocampal zinc concentrations to control values by repletion d 3. The mean retrieval escape latencies of the zinc chloride-repleted rats remained significantly prolonged (75.0%). Collectively, these data indicate the following: 1) feeding a zinc-restricted diet for 3 wk impairs short-term memory in young adult male rats, and 2) repletion with dietary zinc supplemented with L-histidine improves short-term memory function more efficiently than dietary zinc chloride alone. The latter point suggests that dietary zinc supplemented with L-histidine is more bioavailable to the brain than zinc provided as zinc chloride alone. These findings are important in that they highlight the importance of both dietary zinc formulation and the use of functional assessments in determining zinc nutriture.     

Comparative effects of choline chloride and phosphatidylcholine on plasma and liver lipid levels in rats fed a choline-deficient high cholesterol diet

The effects of dietary choline chloride and phosphatidylcholine (PC) on plasma and liver lipid levels were investigated with rats fed a choline-deficient high cholesterol diet. The plasma cholesterol level significantly increased as the dietary level of choline chloride was increased. The addition of PC to the choline-free diet also resulted in an increase in the plasma cholesterol level, but the magnitude of the increase was significantly lower than that by choline chloride. There was no difference, on the other hand, in the effect of choline chloride and PC on the plasma triglyceride level. The contents of cholesterol and triglyceride in the liver markedly decreased in rats fed a diet containing PC at a high level. The fecal excretion of neutral sterol significantly increased by the addition of PC at a high level, but not at a low level. The results indicate that the plasma cholesterol level, but not triglyceride, is differentially influenced by dietary choline chloride and PC, and that PC has both hyper- and antihypercholesterolemic effects when compared with a choline-free diet and a diet supplemented with choline chloride, respectively.     

Effects of High Dietary Protein on Coping Behavior,Memory Performance,and Sensory Discrimination in Rats

Rats consuming a high-protein diet (HP; 50% casein) have increased locomotor activity, are hyper-responsive to nociceptive stimuli, and have increased basal arousal levels, as compared to rats maintained on a normal-protein diet (NP; 20% casein). The present study was performed to determine whether animals on the HP diet display deficits in learning, memory, and sensory discrimination. Male, Sprague-Dawley rats (4 months old) were divided into two groups and fed either the NP diet or the HP diet, ad libitum, for 32 weeks. Then the animals were observed in a variety of behavioral tests. In the swimming cylinder of Porsolt, which tests adaptation to stress, the HP group was significantly less able than the control group to develop an effective coping strategy (p < 0.05). When tested in the Morris Watermaze, animals on both diets performed equally well in the acquisition and recall of spatial information. During the recording of auditory evoked responses to deviant tones, short-term auditory memory traces degraded more quickly in the HP group than in the NP group (p < 0.05). These data suggest that rats fed the HP diet experienced deficits in short-term memory, associated with a diminished ability to cope with acute stress, whereas long-term memory was unaffected.     

锰对大鼠空间学习记忆影响

目的探讨锰染毒大鼠空间学习记忆变化的规律。方法50只雄性大鼠适应性喂养1周后,随机分为5组,即生理盐水组(A组),Mn2+2.5,5,10,20 mg/kg(B、C、D、E组)。腹腔注射生理盐水或MnCl2溶液0.5 mL/d,共30 d。染毒结束后,采用Morris水迷宫试验测定大鼠潜伏期、总路程和穿台次数的变化。结果经多组比较的单因素方差分析,潜伏期、总路程、穿台次数各组均数间差异有统计学意义(F=7.813,P=0.000;F=8.190,P=0.000;F=3.461,P=0.000);与A组比较,B、C、D和E组潜伏期延长,差异有统计学意义(P0.05);与B组比较,D和E组潜伏期延长,差异有统计学意义(P0.05)。与A组比较,C、D和E组总路程延长,差异有统计学意义(P0.01);与B组比较,C、D和E组总路程延长,差异有统计学意义(P0.01)。与A组比较,B、C、D、E 4组穿台次数减少,差异有统计学意义(P0.05)。结论锰染毒可以引起大鼠空间学习记忆障碍。