青,老年大鼠在Morris水迷宫中的学习记忆行为

本实验观察了２２￣２４月龄老年大鼠和５￣６月龄青年大鼠在Ｍｏｒｒｉｓ水迷宫中的学习记忆行为，并用定量分析方法比较两组动物在定位航行及空间搜索试验中的学习记忆，结果表明老年大鼠的寻找平台潜伏期明显延长，而其跨平台次数及在平台象限的游泳路线长度并未减少。提示２４月龄老年大鼠获取学习记忆的能力受损伤而保持记忆的能力维持正常，这可能与二种功能衰老的不同速度及不同神经基础有关。     

丙泊酚对大鼠空间关联记忆能力影响的水迷宫行为测试研究

目的研究注射临床低剂量和高剂量的丙泊酚对大鼠空间关联记忆能力的影响。方法将30只大鼠随机分成3组：对照组、临床低剂量0．1mg／（kg·min）组和临床高剂量0．5mg／（kg·min）组。在注射丙泊酚1d后进行水迷宫实验,包括4d的定位航行和1d的空间探索实验。在定位航行实验中分别对3组大鼠进行I、Ⅱ和Ⅲ象限入水的训练,并记录3组大鼠的逃避潜伏期、游泳路程和游泳速度。在空间探索实验中将大鼠从未训练的Ⅳ象限入水,分别记录平台象限游泳时间、第一环点数以及总得分。结果在第1,2天的定位航行实验中,低剂量组与对照组大鼠的逃避潜伏期没有统计学差异（p〉0．05）;高剂量组逃避潜伏期比对照组显著延长（P〈O．05）。第3,4天的定位航行实验中,3组大鼠之间均未见差异（p〉0．05）。在空间探索实验中,从未训练的Ⅳ象限入水时,对照组、低剂量组和高剂量组大鼠的总得分分别为（2509．36±190．72）、（2378．55±210．69）和（1954．85±174．20）。低剂量组和对照组没有显著性差异（P〉0．05）;高剂量组与对照组存在显著性差异（P〈O．05）,即高剂量组比对照组总得分低。结论注射低剂量的丙泊酚不影响大鼠的空间关联记忆和空间记忆能力;高剂量丙泊酚在注射后前2d内降低大鼠的空间记忆能力,但2d后对大鼠的空间记忆能力没有影响,说明高剂量的丙泊酚降低了大鼠的空间关联记忆能力。     

Morris水迷宫实验中海马相关空间学习记忆的研究进展

空间学习与记忆是脑的高级神经生理活动之一,牵涉多个脑区、多种神经递质和细胞内信号分子,是一项十分复杂的神经生理活动过程。Morris水迷宫是1984年由英国生理学家Morris发明并被用于学习记忆脑机制研究,是用于啮齿类动物空间学习记忆的重要评估工具。海马是大脑的一个重要结构,海马的完整性对于空间学习来说至关重要。Morris水迷宫作为一种检测手段对大鼠海马损伤后效应特别敏感。在Morris水迷宫空间学习方面,海马结构具有特殊性和重要性。海马突触的可塑性和长时程增强效应是空间学习和记忆的神经功能基础。     

重复Morris水迷宫训练提高大鼠空间学习能力却不影响空间记忆能力

采用每周一个周期的Morris水迷宫(MWM)训练(包括第1d的定位航行实验和第2d的空间探索实验),探讨重复MWM训练对大鼠空间学习、记忆能力的影响。在定位航行实验中,动物随机从不同象限连续入水5次以寻找隐藏站台,测量其上台潜伏期来评定其空间学习能力;在第二个训练日中,空间探索实验时撤去隐藏在靶象限的站台,计算大鼠在靶象限活动时间的百分比,评定大鼠的空间记忆能力。采用雄性SD大鼠20只,连续四周重复给予MWM定位航行和探索训练,分别评定大鼠空间学习和记忆能力。结果显示:随着训练次数的增加,动物的上台潜伏期逐渐缩短。同时,第一次的MWM训练能够提高大鼠的空间记忆能力,然而重复训练则轻微提高大鼠的空间记忆能力,但无统计学差异:在1、2、3、4周测得的靶象限内活动时间百分比分别为39.29%±1.62%,39.97%±2.34%,42.05%±2.32%,39.30%±1.64%。本实验结果提示:重复MWM定位航行能够增强动物的空间学习能力,但不影响动物的空间记忆能力。空间学习和记忆能力可能存在不同的形成机制。     

人胚全脑组织小分子提取物改善大鼠空间学习记忆

为检测胚胎组织小分子提取物的生物效应，本实验将或年ＳＤ大鼠阴机分为两组：且腹腔内注射人胚全脑组织小分子提取液。对照组以生理盐水替代。１个月后用Ｍｏｒｒｉｓ水迷宫检测两组大鼠空间学习记忆能力。     

基于小鼠Morris水迷宫和Y迷宫联合试验的多任务行为学测试研究

目的:通过观察小鼠Morris水迷宫和Y迷宫多任务联合试验与单独水迷宫或Y迷宫试验的结果差异,探讨两种记忆相关行为学试验之间是否存在相互干扰。方法:30只成年昆明小鼠随机分为单独水迷宫、单独Y迷宫和水迷宫+Y迷宫(简称联合组)三组。水迷宫试验记录小鼠寻找水下平台的逃避潜伏期、逃避距离、撤除平台后在目标象限内游泳时间和距离占全部时间与距离的百分比;Y迷宫试验记录小鼠在光-电刺激下逃往安全区的错误次数。结果:联合组与单独水迷宫组相比,小鼠逃避潜伏期、逃避距离以及目标象限内游泳所占的时间和距离百分比均无明显差异(P>0.05);联合组与单独Y迷宫组相比,第1和第2 d两组小鼠到达安全区的错误次数无明显差异,第3和第4 d联合组较单独组错误次数明显减少(P<0.05)。结论:两种行为学联合序贯试验对小鼠水迷宫空间学习记忆及第1至2 d Y迷宫工作记忆均不产生干扰;超过2 d的联合实验有助于增强小鼠Y迷宫工作记忆。因此,本研究为联合开展小鼠空间记忆和工作记忆研究提供了实验依据,提示合理地联合不同行为学实验将有助于提高实验效率、降低实验成本。     

人胚全脑组织小分子提取物改善大鼠空间学习记忆

为检测胚胎组织小分子提取物的生物效应,本实验将或年SD大鼠随机分为两组:实验组腹腔内注射人胚全脑组织小分子提取液.对照组以生理盐水替代.1个月后用Morris水迷宫检测两组大鼠空间学习记忆能力.结果显示:实验组寻找平台潜伏期为12.18±4.92秒,显著短于对照组20.92±8.72秒;平台象限游泳距离占总距离百分比为40.51±6.53%,稍高于对照组37.69±5.04%.本结果提示人胚脑组织小分子提取物能作用于中枢神经系统,改善成年鼠的空间学习能力.     

Morris水迷宫训练后即早基因c-Fos及c-Jun在大鼠丘脑前核的表达

目的为探讨Morris水迷宫训练后丘脑前核内c-Fos和c-Jun的表达。方法 30只成年大鼠均分为正常组,假训练组和Morris水迷宫训练组,通过免疫组化和WesternBlot检测c-Fos和c-Jun的表达。结果 Morris水迷宫训练组丘脑前核c-Fos表达水平与假训练组和正常组比较明显增强(P<0.05),丘脑前背侧核显著强于前腹侧核(P<0.05)。训练组c-Jun表达水平与假训练组和正常组比较明显增强(P<0.05)。结论 c-Fos和c-Jun可能参与空间学习记忆过程。     

应用水迷宫测试糖尿病大鼠空间记忆能力变化的研究

目的 研究大鼠患糖尿病后,空间记忆能力和空间关联记忆能力受到的影响.方法 将70只SD大鼠（体质量180 g±20 g）随机分成3组,对照组、1型糖尿病组和2型糖尿病组.采用STZ一次性腹腔注射和联合高脂饲料喂养的方法分别制备1型和2型糖尿病大鼠模型,检测血糖水平.在造模成功的1个月和3个月后,分别进行水迷宫实验,包括4 d的定位航行和1 d的空间探索实验.结果 在糖尿病造模成功的1个月后,大鼠没有发生明显的空间记忆能力或空间关联记忆能力障碍.造模3个月后,在定位航行实验中,2组糖尿病大鼠的逃避潜伏期都比对照组时间长,具有统计学差异（P＜0.05）.实验第2天开始,对照组逃避潜伏期的下降趋势明显,而糖尿病组下降缓慢.1型和2型糖尿病组之间的逃避潜伏期没有显著差异（P＞0.05）.造模3个月后,在空间探索实验中,从训练过的Ⅰ象限入水时,2个糖尿病模型组平台象限游泳时间短,第1环点数和总得分等参数低,与对照组的差异都具有显著意义（P＜0.05）,2型糖尿病组的参数值比1型糖尿病组稍低.从未训练的Ⅳ象限入水时,糖尿病模型组的参数值也均低于正常对照组,具有统计学差异（P＜0.05）,且1型糖尿病组的总得分比2型糖尿病组更低一些.结论 1型或2型的糖尿病大鼠会发生空间记忆能力和空间关联记忆能力的下降.本实验中2型糖尿病组的空间记忆能力比1型糖尿病组受到了更明显的影响,而1型糖尿病组的空间关联记忆能力受到的影响比2型糖尿病组更大.     

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。     

The Effects of Prenatal Stress on Learning in Rats in a Morris Maze

The offspring of female Wistar rats subjected to daily stress (they were placed in an unfamiliar social group for 1 h) during the last third of pregnancy were studied. The offspring of these females were tested for the ability to perform spatial orientation in a Morris water maze at the ages of two and four months. Prenatal stress had no effect on the ability of rats to learn in the Morris maze. However, two-month-old animals subjected to prenatal stress, unlike controls, demonstrated less flexibility in their behavioral strategy in solving the spatial orientation task. These animals were characterized by a clear tendency for their behavior to perseverate. By the age of four months, the differences between the control and prenatally stressed animals had disappeared.     

Use of salient and non-salient visuospatial cues by rats in the Morris Water Maze

In the Morris Water Maze (MWM), an animal learns the location of a hidden platform relative to distal visual cues in a process known as spatial learning. The visual cues used in MWM experiments are invariably salient in nature, and non-salient cues, such as subtle environmental variations, have not traditionally been considered to play a significant role. However, the role of non-salient cues in spatial navigation has not been adequately investigated experimentally. The objective of this experiment was therefore to determine the relative contribution of salient and non-salient visual cues to spatial navigation in the MWM. Animals were presented with an environment containing both types of visual cues, and were tested in three successive phases of water maze testing, each with a new platform location. Probe tests were used to assess spatial accuracy, and several cue variation trials were run in which both salient and non-salient visual cues were manipulated. It was observed that removal of the salient visual cues did not cause a significant deterioration in performance unless accompanied by disruption of the non-salient visual cues, and that spatial navigation was unimpaired when only the salient visual cues were removed from view. This suggests that during place learning in Long-Evans rats, non-salient visual cues may play a dominant role, at least when salient cue presentation is limited to four cues.     

Ontogenetic differences in retention of spatial learning tested with Morris water maze

Two experiments examined retention of spatial learning in rats using a Morris water maze. Retention was scored in terms of probe trial performance when the platform was removed. Latency to reach the platform location, percent of time in the quadrant that had contained the platform, and relative frequency of visits to the platform location were analyzed. Results of the first experiment showed that preweanlings and juveniles exhibited substantial forgetting at 3- and 7-day retention intervals. Forgetting in adults was much lower than that found in the younger animals, and no differences in amount of forgetting appeared between the 3- and 7-day retention intervals at any age. The second experiment showed that forgetting in juveniles was alleviated by a single training trial administered just prior to the probe trial. These results are discussed in terms of ontogenetic differences in memory processing and measurement issues pertinent to the Morris water maze test procedure. © 1997 John Wiley & Sons, Inc. Dev Psychobiol 30: 329–341, 1997     

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。     

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。     

乌拉地尔对吗啡导致的大鼠空间记忆障碍的改善作用

目的研究吗啡对大鼠空间记忆的影响和5-HT1A受体激动剂乌拉地尔对这种影响的改善作用。方法;训练大鼠学习Morris水迷宫任务,检验它们在注射药物情况下回忆空间任务的能力。结果同时注射乌拉地尔(20mg/kg)和吗啡(10mg/kg)的大鼠通过回忆寻找Morris水迷宫隐蔽站台的潜伏期(第一次测验,30.43±9.46;第二次测验,41.00±10.30;单位,秒),显著短于单独注射吗啡的动物(第一次测验,87.00±22.53;第二次测验,96.67±20.85;均为P<0.01);而与对照组动物(第一次测验,16.17±3.74;第二次测验,16.33±2.36)没有显著差别。单因素方差分析对照组和给药情况下吗啡组、吗啡-纳洛酮组和吗啡-乌拉地尔组回忆测验结果分别为第一次测验,16.17±3.74、87.00±22.53、34.67±6.75、30.43±9.46,F1(3,21)=5.866,P<0.01;第二次测验,16.33±2.36、96.67±20.85、22.17±6.46、41.00±10.30,F2(3,21)=8.94,P<0.01。结论乌拉地尔能够显著改善吗啡导致的大鼠空间记忆障碍。     

Intracranial self-stimulation facilitates a spatial learning and memory task in the Morris water maze

Learning and memory improvement by post-training intracranial self-stimulation has been observed mostly in implicit tasks, such as active avoidance, which are acquired with multiple trials and originate rigid behavioral responses, in rats. Here we wanted to know whether post-training self-stimulation is also able to facilitate a spatial task which requires a flexible behavioral response in the Morris water maze. Three experiments were run with Wistar rats. In each of them subjects were given at least five acquisition sessions, one daily, consisting of 2-min trials. Starting from a random variable position, rats had to swim in a pool until they located a hidden platform with a cue located on its opposite site. Each daily session was followed by an immediate treatment of intracranial self-stimulation. Control subjects did not receive the self-stimulation treatment but were instead placed in the self-stimulation box for 45 min after each training session. In the three successive experiments, independent groups of rats were given five, three and one trial per session, respectively. Temporal latencies and trajectories to locate the platform were measured for each subject. Three days after the last acquisition session, the animals were placed again in the pool for 60 s but without the platform and the time spent in each quadrant and the swim trajectories were registered for each subject. A strong and consistent improvement of performance was observed in the self-stimulated rats when they were given only one trial per session, i.e. when learning was more difficult. These findings agree with our previous data showing the capacity of post-training self-stimulation to improve memory especially in rats with little training or low conditioning levels, and clearly prove that post-training self-stimulation can also improve spatial learning and memory.     

Tolerance development to Morris water maze test impairments induced by acute allopregnanolone

The progesterone metabolite allopregnanolone, like benzodiazepines, reduces learning and impairs memory in rats. Both substances act as GABA agonists at the GABA-A receptor and impair the performance in the Morris water maze test. Women are during the menstrual cycle, pregnancy, and during hormone replacement therapy exposed to allopregnanolone or allopregnanolone-like substances for extended periods. Long-term benzodiazepine treatment can cause tolerance against benzodiazepine-induced learning impairments. In this study we evaluated whether a corresponding allopregnanolone tolerance develops in rats. Adult male Wistar rats were pretreated for 3 days with i.v. allopregnanolone injections (2 mg/kg) one or two times a day, or for 7 days with allopregnanolone injections 20 mg/kg intraperitoneally, twice a day. Thereafter the rats were tested in the Morris water maze for 5 days and compared with relevant controls. Rats pretreated with allopregnanolone twice a day had decreased escape latency, path length and thigmotaxis compared with the acute allopregnanolone group that was pretreated with vehicle. Pretreatment for 7 days resulted in learning of the platform position. However, the memory of the platform position was in these tolerant rats not as strong as in controls only given vehicle. Allopregnanolone treatment was therefore seen to induce a partial tolerance against acute allopregnanolone effects in the Morris water maze.     

穹窿海马伞切断鼠脑突触素动态变化及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突触素(SYN)动态变化探讨阿尔茨海默病(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,建模后连续四周给予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(P0.05),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)百分比无明显差异(P0.05),提示空间记忆能力无明显提高。SYN免疫组化实验组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表达可能与提高穹窿海马伞切断大鼠空间学习能力有关。     

Learning in Rats Predisposed to Catatonic States in a Morris Water Maze

Studies in a Morris water maze showed that GC rats, which are predisposed to catalepsy, did not differ from Wistar rats in terms of the proportion of correct attempts or the time taken to find a platform hidden beneath the water. However, in contrast to Wistar rats, rats of the cataleptic strain tended to show passive drifting and demonstrated longer-lasting episodes of immobility in the water. PLM+ rats, which are predisposed to hyperkinesia in the form of pendulum-like horizontal movements of the head and shoulder girdle, took longer to find the platform and showed a reduced proportion of correct platform-finding attempts than Wistar rats and PLM– rats, bred for the absence of pendulum-like movements.