AD样大鼠模型海马内PSD-95表达与学习记忆变化的研究

目的:研究阿尔茨海默病(AD)样大鼠模型海马内突触后致密物-95(PSD-95)表达与学习记忆损伤的元素。方法:健康成年雄性SD大鼠随机分为正常对照组、模型对照组和AD模型组。AD样大鼠模型的建立采用Aβ1-40/Al Cl3双干预法。采用Morris水迷宫和跳台实验检测大鼠的学习记忆能力,采用刚果红染色和尼氏染色观察大鼠海马病理变化,采用免疫印迹的方法检测大鼠海马PSD-95的表达情况。结果:与正常对照组和模型对照组相比,AD模型组大鼠Morris水迷宫逃避潜伏期明显延长(P0.05),跳台实验的反应时间、基础错误次数和错误次数均增加,潜伏期缩短(P0.05)。AD模型组大鼠海马可观察到明显的病理改变,正常对照组和模型对照组中则观察不到。与正常对照组和模型对照组相比,AD模型组大鼠海马PSD-95的表达明显降低(P0.05)。结论:PSD-95在AD样大鼠海马表现为病理性低表达,并且这种病理性低表达很可能与AD样学习记忆损伤存在联系。     

戊四氮诱导癫痫大鼠空间学习记忆受损及海马突触后致密物95表达减少

目的探讨戊四氮诱导癫痫对大鼠空间学习记忆功能的影响及海马突触后致密物95(PSD-95)的表达变化。方法戊四氮(PTZ)腹腔注射诱导慢性癫痫(CEP)模型,采用Morris水迷宫对两组大鼠进行行为学检测,运用免疫组织化学方法观察海马CA1、CA3区PSD-95的表达,反转录聚合酶链反应(RT-PCR)方法检测大鼠海马PSD-95mRNA的表达。结果癫痫组大鼠空间学习记忆能力受损;其海马CA1、CA3区PSD-95免疫阳性产物较对照组明显减少(P<0.05),同时伴有海马PSD-95mRNA表达下降(P<0.01)。结论戊四氮诱导癫痫大鼠空间学习记忆受损可能与海马神经元PSD-95的表达减少有关。     

PTSD大鼠海马CA1区和前额叶皮层突触小泡蛋白的表达

目的:观察创伤后应激障碍(posttraumatic stress disorder,PTSD)大鼠海马CA1区和前额叶皮层(prefrontal cortex,PFC)突触小泡蛋白(synaptophysin)的表达,探讨PTSD大鼠空间记忆损伤的机制。方法:健康成年SD大鼠36只,随机分为正常对照组和模型组,每组18只。模型组采用单次延长应激(single prolonged stress,SPS)构建PTSD大鼠模型。Morris水迷宫实验检测2组大鼠的学习记忆能力,利用免疫组化、Western blot和免疫荧光实验检测海马CA1区和PFC突触小泡蛋白的表达情况。结果:经过Morris水迷宫实验,模型组大鼠从第2天开始逃避平台的潜伏期较对照组均显著延长(P 0.01),目标象限的停留时间均明显降低(P 0.01),穿越原平台位置的次数也明显减少(P 0.01)。在免疫组化、Western blot和免疫荧光实验中,模型组大鼠海马CA1区和PFC突触小泡蛋白的表达较对照组均明显减少(P 0.05或P 0.01)。结论:创伤后应激障碍大鼠空间记忆能力减退,可能与海马CA1区和PFC突触小泡蛋白的表达减少有关。     

西红花苷对阿尔茨海默病大鼠学习记忆及海马LTP的影响

目的:探讨西红花苷对阿尔茨海默病(Alzheimer’s disease,AD)大鼠空间学习记忆能力对海马LTP的影响。方法:健康成年SD大鼠,随机分为正常对照组、AD模型组、西红花苷(低、中、高剂量)组Morris水迷宫实验检测空间学习记忆能力,电生理实验检测海马LTP,Western Blot检测海马GAP-43蛋白表达。结果:AD模型组大鼠寻找水下平台的潜伏期时间较对照组延长(P0.01),西红花苷各剂量组寻找水下平台的潜伏期时间从第二天起,较AD模型组均缩短(P0.01),西红花苷中剂量组和高剂量组的潜伏期时间均短于低剂量组(P0.05),中、高剂量组间的潜伏期时间在各实验日均未见有无显著性统计学差异。强直性高频刺激海马诱发电位的幅值比较,AD模型组低于对照组(P0.01),西红花苷各剂量组高于AD模型组(P0.05),且西红花苷中、高剂量组高于低剂量组(P0.05)。西红花苷各剂量组海马GAP-43表达低于对照组(P0.01),高于AD模型组(P0.01)。结论:西红花苷对AD大鼠学习记忆能力有一定改善作用,增强海马LTP和GAP-43的表达。     

丹参酮ⅡA对癫痫大鼠认知功能障碍的治疗作用

目的:探讨丹参酮(TⅡA)对癫痫大鼠认知功能障碍的治疗作用。方法:将24只成年雄性SD大鼠随机等分为健康对照组、模型组、TⅡA(每日10 mg/kg)治疗组。采用Morris水迷宫实验检测大鼠学习记忆功能,运用电生理技术在脑片水平检测海马CA1区长时程增强(LTP)。结果:(1)模型组大鼠在Morris水迷宫实验中寻找平台潜伏期明显长于健康对照组(P0.05),TⅡA治疗组寻找平台潜伏期较模型组显著缩短(P0.05)。空间探索试验中,模型组大鼠在目标象限的停留时间显著短于对照组(P0.05),TⅡA治疗后大鼠在目标象限的停留时间较模型组明显延长(P0.05)。(2)给予高频强直刺激(HFS)后各均可诱发LTP,且均持续1 h以上,与模型组比较缺氧组HFS刺激后LTP显著减弱(P0.05),TⅡA治疗后LTP较模型组显著增强(P0.05)。结论:TⅡA可显著改善癫痫大鼠认知功能障碍,该作用与TⅡA减轻癫痫大鼠海马LTP抑制有关。     

4-苯基丁酸对创伤后应激障碍大鼠认知能力的影响

目的:观察4-苯基丁酸(4-PBA)对创伤后应激障碍(PTSD)大鼠海马神经元内质网应激(ERS)与凋亡的影响,探讨4-PBA改善PTSD大鼠认知能力的机制。方法:36只成年SD大鼠随机分为正常组、PTSD组和4-PBA+PTSD组,每组12只。PTSD组采用单次延长应激(SPS)构建PTSD大鼠模型,4-PBA+PTSD组从造模次日开始每天于固定时间腹腔注射4-PBA(40 mg/kg),连续给药7 d。Morris水迷宫实验检测各组大鼠的学习记忆能力; Western Blot实验检测各组大鼠海马葡萄糖调节蛋白78(GRP78)、CCAAT增强子结合蛋白同源蛋白(CHOP)及B淋巴细胞瘤-2(Bcl-2)、蛋白激酶R样内质网激酶(PERK)-真核翻译起始因子2α(e IF2α)-活化转录因子4(ATF4)信号通路相关蛋白表达的变化。结果:在Morris水迷宫实验中,与对照组比较,PTSD组大鼠学习记忆能力明显减退(P 0.01);与PTSD组比较,4-PBA+PTSD组大鼠学习记忆功能明显改善(P 0.01)。Western Blot实验结果显示,与对照组比较,PTSD组大鼠GRP78、CHOP的表达明显增加(P 0.01),Bcl-2的表达显著减少(P 0.01),PERK、e IF2α、p-eIF2α表达显著增加(P 0.05),与PTSD组比较,4-PBA+PTSD组大鼠GRP78、CHOP的表达明显减少(P 0.01),Bcl-2的表达显著增加(P 0.05),PERK、e IF2α、p-eIF2α表达显著减少(P 0.05)。结论:4-PBA能够通过激活PERK-eIF2α-ATF4信号通路抑制PTSD大鼠海马神经元的ERS和凋亡,进而改善PTSD大鼠的认知能力。     

APP5肽类似物P165对链脲佐菌素双侧侧脑室注射大鼠海马神经元突触的保护作用

目的观察APP5肽类似物P165对双侧侧脑室注射链脲佐菌素(STZ)大鼠海马神经元突触相关蛋白表达的影响。方法雄性Wistar大鼠45只,随机分为对照组、模型组和治疗组。模型组、治疗组大鼠脑室注射STZ制作痴呆模型,3周后,治疗组以APP5肽类似物P165灌胃治疗,用药4周后,采用Morris水迷宫进行行为学测试;免疫组织化学染色及Western blotting方法观察突触素、α-突触核蛋白和突触后致密区-95蛋白(PSD-95)的表达;电镜观察海马CA1区超微结构改变。结果模型组游泳时间显著长于对照组和治疗组。免疫组织化学染色及Westernblotting均显示模型组海马内突触素、PSD-95蛋白表达与对照组和治疗组相比显著减少,而α-突触核蛋白显著增多。电镜观察可见模型组海马CA1区神经元出现退行性改变,神经毡内突触结构异常。结论脑室注射STZ可影响大鼠海马突触相关蛋白的表达,引起海马神经元和突触的超微结构病变,导致大鼠学习记忆能力减退。APP5肽类似物P165可影响突触蛋白的表达,改善突触功能,有助于恢复大鼠的学习、记忆能力。     

阿尔茨海默病大鼠海马 N-甲基天冬氨酸受体和丝裂酶原激活蛋白激酶的表达

目的探讨N甲基天冬氨酸受体(NMDAR)及丝裂酶原激活蛋白激酶(MAPK)在阿尔茨海默病(AD)发病中的变化及其可能机制。方法将β淀粉样肽(Aβ1～40)1μl(10g L)在立体定位仪下注入大鼠海马建立大鼠AD模型。2周后测水迷宫潜伏期、长时程增强(LTP)、原位杂交方法检测大鼠海马NMDAR mRNA的表达及免疫组织化学SABC法检测MAPK的蛋白表达,并应用显微图像分析系统对两者的表达进行分析。结果AD模型组Aβ注射2周后,水迷宫潜伏期与模型组术前及对照组相比显著延长(P<0.05);模型组刺激前后fEPSP斜率变化及高频刺激增加的幅值与对照组相比显著下降(P<0.01);模型组海马CA1区、CA3区NMDAR mRNA及MAPK蛋白的表达显著降低(P<0.05或P<0.01)。相关性分析表明,AD模型2周后LTP检测的结果与NMDAR mRNA的表达及MAPK的蛋白表达呈正相关。结论Aβ通过抑制MAPK信号通路和降低NMDA受体磷酸化状态,导致大鼠海马LTP降低和学习记忆功能减低,参与AD学习记忆障碍和痴呆形成。     

皮质发育障碍大鼠模型学习记忆行为和海马长时程增强的研究

目的：研究皮质发育障碍（DCD）大鼠模型空间学习记忆及离体海马长时程增强（LTP）变化,探讨DCD大鼠模型认知功能损伤的机制。方法：建立DCD大鼠模型,采用Morris水迷宫实验对DCD大鼠模型和正常对照组进行空间学习、记忆的行为学检测,应用膜片钳技术研究DCD大鼠模型海马脑片CA1区LTP的改变。结果：Morris水迷宫实验中DCD大鼠与正常对照组相比逃避潜伏期延长,穿过原平台位置次数和在原平台象限探索时间百分率下降;DCD大鼠模型海马脑片CA1区LTP诱出率、幅值增加百分率与正常对照组相比均明显降低[（40％vs100％,P〈0．05;（108±5．6）％vs（132±15．4）％,P〈0．05）]。结论：DCD大鼠模型的空间学习记忆能力降低,海马突触可塑性也发生降低。     

西红花苷基于BDNF-TrkB信号通路改善阿尔茨海默症大鼠的学习记忆

目的:观察西红花苷对阿尔茨海默症(AD)大鼠前额叶皮层突触后致密物蛋白95(PSD-95)及脑源性神经营养因子(BDNF)-酪氨酸蛋白激酶受体B(Trk B)信号通路的影响,探讨西红花苷改善AD大鼠学习记忆的机制。方法:SD大鼠随机分为正常组(Control)、Aβ_(25-35)处理组(Aβ)。Aβ_(25-35)+西红花苷组(Aβ+crocin)。除正常组外,其余两组大鼠右侧脑室注射Aβ_(25-35)建立AD大鼠模型,Aβ+西红花苷组从次日开始每天于固定时间腹腔注射西红花苷(40 mg/kg),连续注射14 d。Morris水迷宫检测各组大鼠的学习记忆能力,免疫荧光和Western Blot检测前额叶皮层PSD-95、BDNF、Trk B蛋白的表达。结果:与正常对照组比较,Aβ组逃避平台潜伏期时间明显延长(P 0. 01),目标象限停留时间缩短(P 0. 01),穿越原平台次数减少(P 0. 01)。与Aβ组比较,Aβ+西红花苷组逃避平台潜伏期时间明显缩短(P 0. 01),目标象限停留时间增加(P 0. 01),穿越原平台次数增加(P 0. 01)。免疫荧光和Western Blot结果显示,与对照组相比,Aβ组海马PSD-95、BDNF、Trk B的表达显著性减少(P 0. 05);与Aβ组比较,Aβ+西红花苷组PSD-95、BDNF、Trk B的表达明显增加(P 0. 05)。结论:西红花苷可以通过激活BDNF-TrkB信号通路,增加前额叶皮层BDNF和Trk B的表达,使学习记忆相关蛋白PSD-95的表达增加,改善AD大鼠的学习记忆能力。     

Growth hormone replacement in hypophysectomized rats affects spatial performance and hippocampal levels of NMDA receptor subunit and PSD-95 gene transcript levels

Clinical studies have demonstrated that growth hormone (GH) promotes learning and memory processes in GH-deficient (GHD) patients. In animal studies, GH also influences the N-methyl-D-aspartate (NMDA) receptor system in the hippocampus, an essential component of long-term potentiation (LTP), which is highly involved in memory acquisition. This study was designed to examine the beneficial effects of recombinant human GH (rhGH) on cognitive function in male rats with multiple hormone deficiencies resulting from hypophysectomy (Hx). The performance of an rhGH-treated group and an untreated control group was appraised in the Morris water maze (MWM). The rhGH-treated group performed significantly better in the spatial memory task than the control animals on the second and third trial days. Further training eliminated this difference between the groups. Hippocampal mRNA expression of the NMDA subunits NR1, NR2A and NR2B, insulin-like growth factor type 1 receptor (IGF-1R), and postsynaptic density protein-95 (PSD-95) was then measured in the animals by Northern blot analysis. The results suggest that there may be a relationship between the NMDA receptor subunit mRNA expression levels and learning ability, and that learning is improved by rhGH in Hx rats. Furthermore, a link between MWM performance and PSD-95 was also suggested by this study.     

Periodic abstinence enhances nociception without significantly altering the antinociceptive efficacy of spinal morphine in the rat

Affective disorders are more common in women. The forced swim test acts like a depressive stimulus. Hippocampus and frontal cortex 5-HT_1A receptors of female and male Wistar rats subjected to the forced swim test were compared with a sham group. The forced swim test diminishes (P<0.05) the hippocampus ³H-8OH-DPAT bound in the female rats (184±16 fmol/mg protein) with respect to the male rats (309±41 fmol/mg protein) and to the female sham rats (255±20 fmol/mg protein). The forced swim test increases the frontal cortex 5-HT_1A receptors in the female rats with respect to the female sham group (40.4±5 versus 24.7±4 fmol/mg protein, P<0.05). An increased sensibility of the 5-HT_1A receptors to depressive-stimulus may be one mechanism underlying the higher prevalence of depression in female.     

慢性复合应激对大鼠学习和记忆的影响

本文观察慢性复合应激对海马长时程增强(LTP)和一氧化氮合酶1(NOS1)表达变化的影响,并探讨了其在学习与记忆中的作用。将Wistar大鼠随机分为对照组和慢性复合应激组,每组各10只。应激组动物采用4种应激原无规律、交替性地进行长达6周的慢性复合应激试验。实验过程中测定动物血清皮质酮(CORT)水平,采用Morris水迷宫和Y迷宫测试大鼠学习和记忆成绩,记录海马齿状回LTP群体峰电位(PS)幅值的变化,同时观察海马CA1及齿状回区NOS1阳性神经元数目的变化。结果显示:(1)与对照组比较,慢性复合应激组动物在应激第4周和第6周时,血清皮质酮浓度的比值显著增高(P<0.05,P<0.01);(2)高频刺激(HFS)后各时间点的PS幅值增高更为明显(P<0.01);(3)Morris水迷宫和Y迷宫实验后慢性复合应激组动物的学习和记忆成绩优于对照组(P<0.05,P<0.01);(4)慢性复合应激组和对照组大鼠海马齿状回NOS1阳性神经元个数分别为8.80±3.91和5.44±1.14,两者间有统计学差异(P<0.05)。以上结果提示,慢性复合应激对大鼠的学习和记忆有一定的影响,可能与齿状回群体峰电位幅值增强和NOS1表达增强有关。     

Long-term kindling of the basolateral amygdala impairs copulatory behavior in male rats

This experiment examined the consequences of long-term kindling of the basolateral amygdala on male sexual behavior and the frequency of both spontaneous wet dog shakes (WDS) and those induced by the 5-HT_2A receptor agonist DOI. Results demonstrated that following 60 stimulations of the left basolateral amygdala over a 4-week period, male Long–Evans rats exhibited decrements in every aspect of sexual behavior. Specifically, latencies to mount, intromit and ejaculate were all prolonged following long-term kindling, and ejaculation frequencies were significantly reduced. Furthermore, spontaneous peri-copulatory WDS were increased in kindled rats, suggesting a possible role of the 5-HT_2A receptor. However, countering this suggestion, there were no differences between sham and kindled rats on WDS induced by the 5-HT_2A receptor agonist DOI. These results suggest that kindled rats may exhibit elevated levels of endogenous serotonin during exposure to a female rat, which would attenuate copulatory behavior, while concurrently increasing WDS expression.     

Expression of serotonin2A receptors in Purkinje cells of the developing rat cerebellum

Previous physiological and pharmacological studies have shown that the serotonin_2A (5-HT_2A) receptor is involved in cerebellar functions. However, the expression of 5-HT_2A receptors in the developing cerebellum has not been elucidated to date. In the present immunohistochemical study, we examined developmental changes of the distribution of 5-HT_2A receptors in Purkinje cells of the rat cerebellum from embryonic day 18 (E18) to postnatal day 21 (P21). The weak immunoreaction to 5-HT_2A receptors was found in the deep cerebellar nuclei on E19. In the cerebellar cortex of the hemisphere and the posterior vermis, somata of Purkinje cells became weakly immunoreactive on P0. With the dendritic elongation and arborization, the immunoreaction appeared in the proximal parts of Purkinje cell dendrites. Distal parts of the dendrites became immunoreactive after P12, and were strongly immunolabeled by P21. The present study may provide a structural basis to investigate the roles of 5-HT_2A receptors during the cerebellar development.     

D-半乳糖对大鼠空间学习记忆行为与海马结构电生理以及突触形态学的影响

为了观察经 D-半乳糖处理大鼠的空间学习记忆行为以及在体诱导海马齿状回长时程增强及海马 CA3区突触形态学的变化 ,本研究采用向正常组大鼠每日皮下注射生理盐水 1ml,模型组大鼠每日皮下注射 D-半乳糖 (共 6周 )作为实验材料。对空间学习记忆行为 ,以 Morris水迷宫潜伏期作为判定标准 ;应用在体记录单脉冲刺激穿通纤维在海马齿状回诱发的群体电位 ,测量高频刺激前后单脉冲刺激诱发的电位幅值变化 ,将高频刺激前的记录作为基线值 ,进行组间比较 ;应用透射电镜结合图像分析对大鼠海马 CA3区突触形态结构进行观察。结果证明 :( 1)模型组水迷宫潜伏期成绩显著低于正常组 ( P<0 .0 5 ) ;( 2 )高频刺激前二组间峰潜伏期和电位平均幅值无显著性差异 ,高频刺激后对各时间段群体电位与高频刺激前群体电位峰值之比进行的分析表明 ,模型组在高频刺激后 2 0 min时段开始其比值较正常组显著减小 ( P<0 .0 1) ,模型组长时程增强诱导率显著低于正常组 ( P<0 .0 0 1) ;( 3 )经 D-半乳糖处理的大鼠海马 CA3区突触间隙明显增宽、突触后致密物厚度变薄、突触活性区长度缩短 ( P<0 .0 5 )。结论 :皮下注射 D-半乳糖可损害大鼠的空间学习记忆能力 ,降低大鼠在体海马齿状回长时程增强的诱导率 ,使长时程增强增幅降低 ,并可显?     

5-HT reuptake and 5-HT2 receptors modulate capsaicin-evoked hypothermia in rats

Numerous studies support a role for the endogenous 5-hydroxytryptamine (5-HT) system in the hypothermic effect of capsaicin. None of those studies, however, selectively delineate a role for 5-HT reuptake or 5-HT receptors in this regard. In the present investigation, we determined if the blockade of 5-HT reuptake or the activation of 5-HT_1A or 5-HT₂ receptors modulates capsaicin-evoked hypothermia. The administration of capsaicin (0.2–1 mg/kg, i.m.) produced dose-related hypothermia. Fluoxetine (10 mg/kg, i.p.), a selective serotonin reuptake inhibitor (SSRI), did not affect body temperature. For combined administration, pretreatment with fluoxetine (10 mg/kg, i.p.) significantly attenuated the hypothermia caused by capsaicin (0.5 and 1 mg/kg, i.m.). For the 5-HT receptor experiments, we pretreated rats with either WAY 100635, a 5-HT_1A receptor antagonist, or mianserin, a 5-HT₂ receptor antagonist, and then administered a fixed, hypothermic dose of capsaicin (1 mg/kg, i.m.). WAY 100635 (1 mg/kg, s.c.) administration did not affect capsaicin-evoked hypothermia. This indicates that 5-HT_1A receptor activation does not play a major role in the hypothermic effect of capsaicin. In contrast, pretreatment with mianserin (10 mg/kg, i.p.) enhanced the hypothermic effect of capsaicin (1 mg/kg, i.m.). The present data reveal that capsaicin-evoked hypothermia in rats is attenuated by the blockade of 5-HT reuptake and enhanced by the antagonism of 5-HT₂ receptors.     

侧脑室注射链脲佐菌素对大鼠海马突触相关蛋白PSD-95和Shank 1表达的影响

目的 观察侧脑室注射链脲佐菌素对大鼠脑PSD-95和Shank1表达的影响.方法 将大鼠随机分为正常对照组和模型组,模型组大鼠双侧侧脑室注射链脲佐菌素3mg/kg,第3d重复此剂量;对照组以人工脑脊液代替链脲佐菌素.21d后,取大鼠海马,用免疫组织化学和Western blotting方法观察突触相关蛋白PSD-95和Shank1的表达.结果 与对照组相比,模型组大鼠海马PSD-95和Shankl阳性细胞明显减少,PSD95和Shank1蛋白表达降低.结论 侧脑室注射链脲佐菌素使海马PSD-95和Shank1表达减少,干扰了神经元突触信号传导.