Extensive training in a maze task reduces neurogenesis in the adult rat dentate gyrus probably as a result of stress

It has recently been shown that hippocampal neurogenesis can be modulated either directly or indirectly by ascending cholinergic inputs from the basal forebrain. In the present work, we sought to address whether extended training in a spatial navigation task would affect hippocampal neurogenesis in the presence of a severe and selective cholinergic depletion. Young female rats received stereotaxic injections of the immunotoxin 192 IgG-saporin into the basal forebrain nuclei and/or the cerebellar cortex. Starting from 4 to 5 weeks post-lesion, and for the subsequent 2 weeks, the animals were trained on paradigms of reference and working memory in the water maze and received single daily i.p. injections of bromodeoxyuridine (BrdU) at the end of each testing session. In line with previous observations, a dramatic 80% decrease in neuron proliferation was seen in the dentate gyrus of lesioned animals, as compared to vehicle-injected or intact controls. Interestingly, however, rats subjected to maze training over 2 weeks, irrespective of their learning success, exhibited significantly fewer newborn neurons than matched controls with no maze exposure. Thus, at least for the type of task used here, which has previously been shown to impose a certain degree of stress, extended training and learning does not appear to affect proliferation in the dentate gyrus.     

急性应激和急性吗啡暴露对不同年龄大鼠空间记忆的影响

目的：观察急性应激和／或急性吗啡暴露（2mg／kg）对4周龄和10周龄大鼠记忆的影响。方法：建立平台应激模型．运用Morris水迷宫来观察急性应激和急性吗啡暴露对4周龄和10周龄大鼠空间记忆的影响。结果：①4周龄组：急性应激组、吗啡组及急性应激加吗啡组在目标象限停留的时间均比对照组短（P〈0．05）。②10周龄组：急性应激组在目标象限停留的时间比对照组短（P〈0．05）。吗啡组及急性应激加吗啡组与对照组相比差异无显著性（P〉0．05）。③两个年龄段的比较：10周龄吗啡组、急性应激加吗啡组在目标象限停留的时间均比4周龄要长（P〈0．05）。而急性应激组和对照组这两个年龄段分别比较差异无显著性（P〉0．05）。两个年龄组中各组大鼠的运动速度分别与对照组相比差异无显著性（P〉0．05）。结论：①急性平台应激损害4周龄和10周龄大鼠的记忆，但没有明显年龄差异；②急性吗啡暴露（2mg/kg）对4周龄大鼠的记忆有损害作用，而对10周龄的记忆没有影响，存在年龄差异。③急性应激加吗啡损害了4周龄大鼠的记忆保持，而对10周龄大鼠的记忆保持无影响，存在年龄差异。     

慢性应激和急性吗啡暴露对不同年龄大鼠空间记忆的影响

目的：观察慢性应激和/或急性吗啡暴露（2mg／kg）对4周龄和10周龄大鼠记忆的影响。方法：建立平台应激模型，运用Morris水迷宫来观察慢性应激和急性吗啡暴露对4周龄和10周龄大鼠空间记忆的影响。结果：①4周龄组：吗啡组在目标象限停留的时间比对照组短（P〈0．05）。慢性应激及慢性应激加吗啡组与对照组相比差异无显著性（P〉0．05）。②10周龄组：慢性应激组、慢性应激加吗啡组在目标象限停留的时间均比对照组长（P〈0．05）。而吗啡组与对照组相比差异无显著性（P〉0.05）。③10周龄慢性应激组、吗啡组及慢性应激加吗啡组在目标象限停留的时间均比4周龄要长（P〈0．05）。而对照组在两个年龄段比较差异无显著性（P〉0．05）。两个年龄组中各组大鼠的运动速度分别与对照组相比差异无显著性（P〉0．05）。结论：①慢性平台应激对10周龄大鼠记忆起易化作用，对4周龄没有明显的影响。②急性吗啡暴露（2mg／kg）对4周龄大鼠的记忆有损害作用，而对10周龄的记忆没有影响。③慢性应激加吗啡对4周龄大鼠的记忆无影响，对10周龄大鼠的记忆有易化作用。     

Effects of pre-training morphine on spatial memory acquisition and retrieval in mice

The opioid system plays an important role in memory processess. Morphine mimics endogenous opioids by acting on opioid receptor in brain to regulate memory. However, the effects of morphine on spatial memory acquisition are controversial. Also, little evidence has suggested that morphine could affect the retrieval of spatial memory. In the current study, effects of pre-training morphine and naloxone on the acquisition vs. retrieval of spatial reference vs. working memory were examined using discrete water maze tasks in C57BL/6 mice. Pre-training morphine administration (7.5 and 15 mg/kg, i.p.) impaired the acquisition of both spatial reference memory and working memory. Motivation to escape from the water maze was not affected by morphine. Pre-test morphine also inhibited the retrieval of spatial working memory but not reference memory. The effects of morphine on the acquisition and retrieval of spatial working memory were eliminated by naloxone pretreatment (1 mg/kg). These results indicate that morphine could differentially modulate a variety of aspects of spatial memory and these effects are mediated by the mu-opioid receptor.     

痫愈益智汤对癫痫大鼠行为和海马脂质过氧化的影响

目的:观察中药复方痫愈益智汤对癫痫大鼠的发作,学习记忆能力及海马脂质过氧化的影响。方法:以戊四氮(pentylenetetrazole,PTZ)腹膜腔注射建立大鼠慢性点燃模型,实验分为四组:生理盐水组(normal saline,NS)、痫愈益智汤组(XianyuYizhi,XYYZ)、丙戊酸钠口服液组(Sodium Valproate Oral Solution,VPA)和丙戊酸钠口服液痫愈益智汤联用组(VPA+XYYZ),每组15只。各组在造模同时即开始灌胃给药,持续4周。完全点燃的大鼠进行水迷宫实验。用比色法检测海马丙二醛(malondialdehyde,MDA)、还原型谷胱甘肽(glutathione,GSH)水平和总超氧化物歧化酶(superoxide dismutase,SOD)活力。结果:XYYZ组、VPA组和VPA+XYYZ组大鼠点燃率、死亡率明显低于NS组,点燃潜伏期也明显长于NS组。大鼠水迷宫实验中,XYYZ组和VPA+XYYZ组大鼠穿越平台的次数明显多于NS组(P<0.05)。各干预组在平台所在象限停留的时间明显长于NS组(P<0.05)。各干预组和NS组相比,大鼠海马内MDA含量明显降低(P<0.05),GSH和SOD含量明显升高(P<0.05)。结论:痫愈益智汤通过抗氧化损伤机制保护神经元,从而拮抗癫痫的发生并对癫痫鼠的认知功能起到改善作用。     

鼠脑穹窿海马伞切断突触素动态变化及Morris水迷宫重复训练对其影响

目的在Morris水迷宫(MWM)重复训练的过程中观察穹窿海马伞切断大鼠的SYN动态变化探讨AD的发病机制和MWM重复训练学习和记忆能力对AD的影响,为临床应用提供实验依据。方法采用Wistar大鼠60只,随机分为对照组、模型组和实验组,建模后连续4周给予Morris水迷宫重复训练定位航行和探索训练,分别评定大鼠空间学习和记忆能力,后进行海马突触素(SYN)免疫组化染色和超微电镜观察并进行统计学处理。结果随着训练次数的增加,对照组、模型组、实验组逃逸时间均逐渐缩短,实验组短于模型组,长于对照组(P<0.05),差异有统计学意义,提示空间学习能力得到提高。对照组、模型组和实验组大鼠在靶象限活动时间(s)百分比差异没有统计学意义(P<0.05),提示空间记忆能力无明显提高。免疫组化结果显示实验组SYN表达高于模型组,弱于对照组。结论MWM重复训练增加海马SYN表达可能早提高穹窿海马伞切断大鼠空间学习能力的重要机制。     

急、慢性高原缺氧对成年大鼠空间学习和记忆功能的影响

 目的： 探讨急性和慢性高原缺氧对成年大鼠空间学习和记忆功能的影响。方法： 研究分三部分。实验一：成年雄性SD大鼠分为平原组（A组）和急性高原缺氧组（B组）（n=15）,B组于低压舱模拟海拔7 000 m高原连续暴露72 h后返回平原,24 h后两组同时进行Morris水迷宫定位巡航实验,连续训练3 d,每天4次,记录大鼠寻找平台的时间,第4天撤除平台,进行空间探索实验并记录大鼠穿越平台的次数和在目标象限停留的时间。实验二：成年雄性SD大鼠分为平原组（C组）和慢性高原缺氧组（D组）（n=13）,D组置于低压舱模拟海拔6 000 m高原连续暴露35 d后返回平原,24 h后两组同时进行Morris水迷宫定位巡航实验,连续训练5 d,每天4次,第6天进行空间探索实验。实验三：成年雄性SD大鼠先进行Morris水迷宫定位巡航实验和空间探索实验(方法同实验二）,于空间探索实验后随机分为平原组（E组）和急性高原缺氧组（F组）（n=15）,F组于低压舱模拟海拔7 000 m高原连续暴露72 h后返回平原,2 h后两组再同时进行空间探索实验。结果： B组缺氧暴露后第1天寻找平台的时间较A组显著缩短（P<0.05）,B组穿越平台次数和在目标象限停留时间百分比与A组比较差异无统计学意义。D组寻找平台潜伏期时间、穿越平台次数及在目标象限停留时间的百分比与C组相比,差异均无统计学意义。F组与E组缺氧前的各项指标均无显著差异,缺氧暴露后,F组穿越平台次数和在目标象限停留时间的百分比与E组相比差异无统计学意义。结论： 在本实验观察期内,急、慢性模拟高原缺氧对成年雄性大鼠对空间位置觉和方向觉（空间定位）的学习和记忆能力无显著影响（P>0.05）。急、慢性高原缺氧对工作记忆和空间参考记忆等功能的影响有待进一步研究。     

Effects of treadmill running on spatial learning and memory in streptozotocin-induced diabetic rats

Previous studies have shown an association between diabetes mellitus and impairments in learning and memory. These deficits were partially reversed by the use of insulin. Due to the fact that exercise has positive effects on many physiological systems, including the central nervous system, the present study, evaluated the effects of treadmill running on spatial learning and memory in streptozotocin (STZ)-induced diabetic rats. The exercise program was treadmill running at 17 meters per minute (m/min) at 0° inclination for 40 minutes per day (min/day), 7 days/week, for 12 weeks. Experimental groups were: the control-rest, the control-exercise, the diabetes-rest and the diabetes-exercise. Spatial learning and memory was investigated by Morris water maze test in the rats after 12 weeks of diabetes induction and the exercise period. Our data showed that spatial learning and memory was significantly impaired in the diabetes-rest group with respect to the control-rest group. However, there were no differences between the other groups. The present results suggest that spatial learning and memory is affected under diabetic conditions and that treadmill running prevents these effects. The data correspond to the possibility that treadmill running is helpful in the prevention and alleviation of the cognitive decline in diabetes mellitus.     

孕酮抗氧化作用对去卵巢小鼠学习记忆能力的影响

目的观察孕酮与小鼠学习记忆功能的维持和改善是否存在相关性,并探讨其机制。方法60只雌性昆明小鼠随机分为5组,除SHAM组外,其余各组小鼠行双侧卵巢切除术。术后对各组小鼠分别腹腔注射不同剂量孕酮或生理盐水。Morris水迷宫测试训练检测各组小鼠学习记忆能力,随后取脑,检测海马组织的SOD、MDA含量及T-AOC。结果OVX组在若干个测试训练时段其空间学习记忆能力显著较差,而孕酮各剂量组表现较好。海马组织SOD含量:SHAM组和孕酮各计量组均显著较高(P<0.05);MDA含量:SHAM组和HP组显著较低(P<0.05);T-AOC:SHAM组和HP组显著增高(P<0.05)。结论雌、孕激素的缺乏会引起成年雌性小鼠学习记忆能力下降,孕酮的长期补充治疗可以通过组织抗氧化作用,抵抗脂质过氧化反应,提高组织的抗氧化能力,来缓解或改善小鼠学习记忆功能障碍。     

抗氧化剂TA9901对加速老化鼠(SAM-P/8)行为学的影响

目的　观察抗氧化剂TA990 1对实验动物学习记忆功能的影响 ,为其临床应用提供实验依据。方法　用加速老化鼠 (SAM) P/ 8小鼠 2 0只随机分为对照组、TA1组 (0 0 5 %TA990 1)、TA2组 (0 5 %TA990 1)、和VE组 (5 0 0mgVE/kg饲料 ) ,分别进行Morris水迷宫行为学测试 ,观察TA990 1对SAM P/ 8小鼠的作用。结果　对照组平均逃避潜伏期是 (6 2 78± 8 75 )sec ,TA1组、TA2组和VE组的逃避潜伏期分别为 (5 3 94± 5 79)、(36 38± 4 77)和 (40 2 2± 5 5 1)sec。与对照组相比 ,TA2组和VE组逃避潜伏期减少均具有显著性意义 (P <0 0 5 ) ,TA1组和TA2组比较也有显著性差异 (P <0 0 5 )。空间探索试验结果以平台象限的游泳距离占总的游泳距离的百分比判断动物的空间学习记忆能力 ,对照组、TA1组、TA2组和VE组小鼠的平台象限游泳距离所占的百分比分别为 (11 33± 2 5 1)、(15 0 9± 4 0 2 )、(2 4 35± 7 89)和 (2 0 93± 5 0 2 ) % ,对照组与TA2组和VE组相比 ,差异均具有显著性 (P <0 0 5 ) ,TA1组与TA2组之间差异也有显著性 (P <0 0 5 )。结论　TA990 1能显著改善SAM P/ 8的学习记忆能力 ,初步显示TA990 1有改善学习记忆功能及抗痴呆的药理作用。     

Effect of reversible inactivation of locus ceruleus on spatial reference and working memory

The locus coeruleus (LC) is the largest source of norepinephrine (NE) in the prefrontal cortex and the hippocampus, influencing the cognitive functions of these areas. All previous studies have studied the role of the LC–NE system on learning and memory using the irreversible lesion technique, employing either electrocoagulation or excitotoxins. However, the reversible functional inactivation of LC by means of stereotaxic local microinjection of lidocaine could measure the phases of memory processing (acquisition, consolidation and retention) without any interference with the other cognitive functions of the same structure either during earlier or later phases of the same process. The aim of this study is to investigate LC involvement in spatial reference and working memory by inducing bilateral pre-training, post-training and pre-retrieval lidocaine functional inactivation using the Morris water maze task. The reversible inactivation of LC was applied at different stages of spatial memory formation: (1) immediately before the training sessions to determine the effects on acquisition of the both reference and working memory; (2) immediately after the training session to evaluate effects on both spatial memory consolidation and retention of working memory; and (3) immediately before the 24 h retention session to analyze the effects on the retrieval process of reference memory. Our results indicate that the bilateral reversible inactivation of LC significantly impaired the acquisition of reference and working memory, while it had no effect on consolidation and/or retention of such memories in the Morris water maze (MWM) task. Therefore, the noradrenergic system of the LC may play a more important role in acquisition than in consolidation and retrieval of spatial memory in wistar rats.     

Long-term administration of green tea catechins prevents age-related spatial learning and memory decline in C57BL/6 J mice by regulating hippocampal cyclic amp-response element binding protein signaling cascade

Flavonoid-rich foods have been shown to be effective at reversing age-related deficits in learning and memory in both animals and humans. However, little investigation of the preventative effects of flavonoids on the naturally aged animals was reported. In our study, 14-month-old female C57BL/6 J mice were orally administered 0.025%, 0.05% and 0.1% green tea catechins (GTC, w/v) in drinking water for 6 months; we found that a supplementation with 0.05% or 0.1% GTC prevented age-related spatial learning and memory decline of mice in the Morris water maze. Better performance of GTC-treated mice was associated with increased levels of cAMP-response element binding protein (CREB) phosphorylation in the hippocampus. The expressions of brain-derived neurotrophic factor (BDNF) and Bcl-2, two target genes of CREB which can exhibit long-term regulatory roles in synaptic plasticity and synaptic structure, were also increased. We also found that long-term 0.05% or 0.1% GTC administration prevented age-related reductions of two representative post-synaptic density proteins PSD95 and Ca²⁺/calmodulin-dependent protein kinase II, suggesting that synaptic structural changes may be involved. These results demonstrated that long-term 0.05% or 0.1% green tea catechin administration may prevent age-related spatial learning and memory decline of female C57BL/6 J mice by regulating hippocampal CREB signaling cascade.     

Different involvement of ventral and dorsal norepinephrine pathways on norepinephrine reuptake inhibitor-induced locomotion and antidepressant-like effects in rats

Two experiments were performed to investigate the involvements of ventral and dorsal norepinephrine bundle (VNB and DNB) in a selective norepinephrine reuptake inhibitor (NRI) reboxetine (RBX)-induced locomotion and antidepressant-like effects. Rats in the Experiment 1 received a local brain injection of 6-hydroxydopamine (6-OHDA) or an intraperitoneal injection of N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP-4) to lesion their VNB or DNB, respectively. Acute effects of RBX (10 mg/kg, i.p.) on the locomotor activity and the forced swim test (FST) were measured 14 days after the lesion. In Experiment 2, activities of the norepinephrine transporter (NET) and the protein kinase C (PKC) in cortex, hippocampus, and locus coeruleus (LC) were detected by western blot after 14 days chronic RBX treatment. Results showed that the antidepressant-like effect of RBX was blocked in VNB lesion but augmented in DNB lesion, and was not relevant to the RBX-induced hypoactivity. Fourteen-days RBX treatment altered the activities of NET and PKC in LC but not hippocampus or cortex. The possible involvement of VNB and DNB in the RBX-induced antidepressant-like effect is discussed.     

雌激素对阿尔茨海默病去势雌性SD大鼠学习记忆能力的影响

目的观察雌激素对阿尔茨海默病(AD)大鼠学习记忆能力的影响。方法首先采用Aβ1～40,1μL(10μg/μL)立体定位SD大鼠单侧海马内注射建立AD动物模型,二周后双侧卵巢切除术(OVX)制备去卵巢大鼠模型后给予雌激素替代治疗(ERT),最后通过Morris水迷宫观察动物模型的学习、记忆能力变化情况。结果 ERT组AD动物模型的水迷宫逃避潜伏期和目标象限游泳时间比OVX组明显缩短(P0.05)。结论雌激素具有改善AD大鼠模型认知功能的作用。     

宫内缺氧对新生小鼠额叶皮质神经元内nNOS表达及对成年小鼠学习记忆能力的影响

为探讨孕鼠宫内缺氧对新生小鼠发育时期额叶皮质神经元内nNOS表达及对成年小鼠学习记忆能力的影响,本研究采用Tapanainen建立的缺氧模型致胎龄13、15、17d小鼠宫内缺氧,然后采用Nissl染色观察新生鼠发育时期P1、P7、P14、P28、P90额叶皮质内神经元的数量和形态变化;免疫组织化学染色方法观察新生鼠发育时期P1、P7、P14、P28、P90脑组织内nNOS阳性神经元的表达;Morris水迷宫实验检测P90小鼠的学习和记忆能力。结果显示:与正常组比较,宫内缺氧组小鼠额叶皮质神经元数量明显减少,额叶皮质神经元内nNOS的表达明显减弱。宫内缺氧组小鼠逃避潜伏期延长及穿环次数明显减少。以上结果提示宫内缺氧可导致新生鼠额叶皮质神经元数量明显减少及nNOS的表达也明显减弱,并引起成年小鼠学习记忆能力降低。     

雌激素对阿尔茨海默病模型大鼠学习记忆的影响

目的:探讨雌激素对阿尔茨海默病(Alzheimer’s disease,AD)模型大鼠学习记忆能力的影响。方法:选取雌性SD大鼠24只,随机分为假手术组、卵巢切除组(ovariectomy,OVX)、OVX+苯甲酸雌二醇组(estradiolbenzoate,EB),每组8只。于海马注射Aβ1-42建立AD大鼠模型,通过Morris水迷宫观察大鼠的学习记忆能力,同时用ELISA检测脑组织超氧化物歧化酶(super oxide dismutase,SOD)、丙二醛(malondialdehyde,MDA)、乙酰胆碱酯酶(acetylcholine esterase,ACh E)的活性,用免疫组化分析神经元型一氧化氮合酶(n NOS)并测定其OD值。结果:与OVX组比较,OVX+EB组逃避潜伏期明显缩短(P0.05),原平台象限活动时间明显增加(P0.05),穿越原平台次数明显增多(P0.05)。雌激素作用还提高大鼠脑组织SOD、ACh E和n NOS活性,降低MDA活性(P0.05)。结论:研究表明雌激素可改善AD模型大鼠的学习记忆能力,其机制可能通过提高脑组织SOD、ACh E和n NOS活性,降低MDA活性有关。     

Effects of P2, a peptide derived from a homophilic binding site in the neural cell adhesion molecule on learning and memory in rats

The neural cell adhesion molecule (NCAM) plays a pivotal role in neural development, regeneration, synaptic plasticity, and memory processes. P2 is a 12-amino-acid peptide derived from the second immunoglobulin-like (Ig) module of NCAM mediating cis-homophilic interactions between NCAM molecules present on the same cell. P2 is a potent NCAM agonist, capable of promoting neuronal differentiation and survival in vitro. The aim of this study was to assess the effect of P2 on learning and memory. Rats treated with P2 intracerebroventricularly (1 h prior to test) performed significantly better than controls in the reinforced T-maze, a test of spatial working memory. Further, rats treated with P2 exhibited decreased anxiety-like behavior while learning the T-maze task. In the social recognition test, both intracerebroventricular (1 h prior to test) and systemic (1 and 24 h prior to test) P2 treatment enhanced short-term social memory and counteracted (administration 24 h prior test) scopolamine-induced social memory impairment. In contrast, P2 (1 h prior to test) did not significantly improve long-term (24 h) retention of social memory, nor did it have any significant effects on long-term memory evaluated by the Morris water maze (administration between 2 days before training and 5.5 h posttraining). In the open field test, P2 (1 h prior to test) decreased general locomotion and rearing, but did not influence any other anxiety-related behaviors, indicating only a minimal influence on baseline anxiety levels. Taken together, these data indicate that in vivo P2 enhances short-term memory and protects against the amnestic effects of scopolamine, while modulating emotional behavior in a learning or novelty-related task.     

灵芝孢子油与深海鱼油联合应用对小鼠学习记忆及海马神经元表达NOS的影响

目的探讨灵芝孢子油与深海鱼油联合应用对小鼠学习记忆及海马神经元表达NOS的影响。方法将受孕小鼠随机分为4组,自受孕第1天起分别胃饲生理盐水、灵芝孢子油、深海鱼油和灵芝孢子油加深海鱼油。在母鼠分娩21d后改为胃饲其幼鼠,然后将出生后45d的幼鼠处死。处死前进行Morris水迷宫行为学测试,处死后应用酶组织化学法检测海马神经元NOS的表达。结果在Morris水迷宫检测中,灵芝孢子油组、深海鱼油组和灵芝孢子油加深海鱼油组小鼠的逃逸潜伏期明显缩短。灵芝孢子油组和灵芝孢子油加深海鱼油组的小鼠平台象限游泳距离有增加。灵芝孢子油加深海鱼油组的小鼠大脑海马NOS阳性神经元与其它组的小鼠比较有显著性增加。结论灵芝孢子油和深海鱼油联合应用能够促进小鼠学习记忆能力及其大脑海马神经元表达NOS。     

Ghrelin对小鼠空间记忆和海马神经元突触及生长激素促分泌素受体表达的影响

目的 探讨Ghrelin对正常小鼠空间学习记忆能力和海马神经元突触及生长激素促分泌素受体（GHS-R）表达的影响。方法 8周龄小鼠 20只,随机分为实验组和对照组,分别腹腔注射Ghrelin和等量生理盐水,通过水迷宫实验检测小鼠的空间学习记忆能力,免疫组织化学实验检测海马Ghrelin受体GHS-R表达,并通过电子显微镜观察海马突触的超微结构变化。结果 水迷宫隐匿平台实验中,第2、3、4天,实验组小鼠的逃避潜伏期与对照组相比明显缩短（P <0.05）,跨越平台次数明显增加(P <0.05）,海马CA3和齿状回区GHS-R免疫阳性产物表达明显增强（P <0.05）,神经元突触数量明显增加（P <0.05）。结论 Ghrelin可能通过结合GHS-R,增加海马神经元突触数量,显著改善小鼠的空间学习记忆能力。     

短期丰富生存环境对中老年雌性大鼠海马结构及其内有髓神经纤维的影响

目的 探讨短期丰富生存环境干预对中老年雌性大鼠海马结构及其内有髓神经纤维的影响。 方法 将20只14月龄的雌性SD大鼠随机分为丰富生存环境组和标准环境组,每组各10只,对丰富生存环境组的动物给予4个月丰富生存环境干预, 标准环境组于普通标准环境下饲养4个月;然后每组各随机选取5只,采用Morris水迷宫对大鼠的空间学习能力进行测试,然后运用透射电子显微镜和体视学方法分别对大鼠大脑海马结构及其内有髓神经纤维进行定量研究。 结果 短期丰富生存环境组中老年雌性大鼠与标准环境组相比,其空间学习能力明显增强;丰富生存环境组海马结构内有髓神经纤维总长度和总体积分别显著增加了43.4%和47.4%,且有髓神经纤维总长度的增加主要是由于细小直径的有髓神经纤维长度增加所致。海马结构总体积和海马结构内有髓神经纤维直径未见改变。 结论 4个月丰富生存环境干预对于14月龄雌性大鼠空间学习能力、海马内有髓神经纤维均有显著性影响。