氯胺酮单次注射对创伤后应激障碍模型动物场景恐惧行为的影响及机制

目的在大、小鼠创伤后应激障碍(PTSD)模型上评价氯胺酮单次预防给药对大、小鼠场景恐惧表达的影响,并基于脑源性神经营养因子(BDNF)表达调节研究其作用机制。方法建立小鼠条件性恐惧和大鼠时间依赖性敏化(TDS)2种PTSD动物模型,在条件性恐惧训练前不同时间点进行不同剂量的单次给药,采用僵住行为测试评价氯胺酮在2个模型上对场景恐惧的影响。在小鼠条件性恐惧模型中,训练前0.5 h单次预防性给予氯胺酮10 mg·kg-1,分别于造模训练后24 h和第14天取脑,采用Western印迹法检测大脑皮质BDNF的表达。结果行为学测试结果表明,在小鼠条件性恐惧模型上,氯胺酮10 mg·kg-1分别在训练前第7天、24 h和0.5 h单次预防给药,训练后24 h场景恐惧测试中各组小鼠僵住时间百分率无明显差异;而训练前0.5 h单次预防性ip氯胺酮10 mg·kg-1,在训练后第14天显著降低小鼠僵住时间百分率(P<0.05);在大鼠TDS模型上,条件性恐惧训练前0.5 h单次ip氯胺酮10 mg·kg-1可显著降低TDS大鼠僵住次数百分率(P<0.05)。Western印迹结果显示,在训练后24 h和第14天,与正常对照组相比,模型组小鼠大脑皮质BDNF表达均显著降低(P<0.05);训练前0.5 h给予氯胺酮10 mg·kg-1组,在训练后24 h和第14天小鼠皮质BDNF的表达较模型组均显著升高(P<0.05)。结论氯胺酮单次预防性给药可减少小鼠场景恐惧的表达,该作用与给药剂量有关,且具有延迟起效的特点,但延迟起效作用与恐惧记忆形成后大脑皮质BDNF表达改变在时间上不具有一致性;氯胺酮单次给药可降低TDS增敏的大鼠场景恐惧的表达,此作用与给药时间点密切相关。     

急性应激障碍向创伤后应激障碍转化模型的建立

目的建立小鼠急性应激障碍(ASD)向创伤后应激障碍(PTSD)转化的模型。方法雄性C57BL/6J小鼠(6-8周龄)采用电击刺激(0.8 m A,每次10 s,每天15次,3 d)造模,造模后24 h和28 d后测量焦虑、回避、再体验症状。通过行为轮廓法(behavior profile),分离出在急性期和慢性期患病的小鼠。结果在电击应激后24 h,应激组小鼠表现出明显的回避行为(P=0.0012)、在电击环境中的僵直行为(P<0.01)和明显的焦虑行为(P=0.002)。在电击后28天,应激组小鼠同对照组相比仍然表现出显著的焦虑行为(P=0.0889)、回避行为(P<0.01)和在电击环境中的僵直行为(P=0.0138)。通过行为轮廓法,以对照组各项行为学数据的平均值±0.5标准差为界限,定义在三项行为学测试中,均超过或低于界限的小鼠为患病小鼠。通过筛选,在应激后24 h对照组小鼠有1只患病,模型组有15只患病,患病率分别为4%和57.69%。在应激后28 d,对照组小鼠患病2只,应激组患病8只,患病率分别为8%和30.77%,应激组小鼠的创伤后应激障碍患病率同临床数据相似。其中应激组在急性期和慢性期均患病的小鼠有6只,急性应激障碍向创伤后应激障碍的转化率为40%。结论成功建立了小鼠急性应激障碍向创伤后应激障碍转化的模型,可用于相关机制研究和药物筛选。     

大鼠恐惧应激模型的建立及指标筛选

目的探讨条件恐惧应激模型建立的可行性以及此模型的有效性。方法 64只健康雄性Wistar大鼠随机分为恐惧模型组与对照组,每组32只,采用改良的Takashi法建立条件恐惧模型。通过对大鼠恐惧行为的观察、自发活动试验的测定,动态观察各组大鼠在不同恐惧应激时期行为学方面的变化;采用放射免疫学方法测定大鼠在不同恐惧应激时期血清中皮质酮、C反应蛋白浓度的变化。结果①恐惧模型组冻结时间显著高于对照组(P<0.01),证明造模成功;②第1周两组大鼠体重无显著性差异,第2、3、4周两组大鼠体重比较有显著性差异(P<0.05);③两组大鼠自发活动比较,恐惧模型组大鼠活动性显著低于对照组(P<0.05);④恐惧模型组第1、2、3、4周血清皮质酮均显著高于对照组(P<0.05);⑤恐惧模型组第1、2、3、4周血清C反应蛋白均显著高于对照组(P<0.05)。结论条件恐惧模型动物冻结时间明显升高,且行为学改变持续时间较长。血清酶学检测显示恐惧模型动物处于较高应激水平,是较为理想可靠的恐惧动物模型。     

大鼠边缘下区H_2S/CBS在条件性恐惧消退保持中的作用及机制研究

目的探讨条件恐惧大鼠边缘下区胱硫醚-β-合成酶(cystathionine-β-synthase,CBS)/硫化氢(hydrogen sulfide,H_2S)变化,及H_2S对条件恐惧消退保持的作用及机制。方法采用以声音为提示的足底电击建立大鼠恐惧记忆模型,仅给予声音信号进行恐惧消退训练。Western blot和亚甲基蓝法检测边缘下区CBS/H_2S含量,在体细胞外电生理技术记录边缘下区神经元放电情况。结果结果表明:(1)大鼠条件恐惧训练后边缘下区CBS/H_2S含量减少(P<0.01),僵立行为加重(P<0.01);消退训练后边缘下区CBS/H_2S含量有所回升(P<0.01,P<0.05),僵立行为有所减轻(P<0.01)。(2)外源性补充H_2S后可改善消退训练大鼠的僵立行为(P<0.01)。(3)边缘下区微量压力注射硫化氢供体L-半胱氨酸使该区神经元自发放电频率升高(P<0.01)。结论边缘下区CBS/H_2S参与调节恐惧记忆的消退过程,外源性增加H_2S可增强条件恐惧消退行为,该作用可能与其增加边缘下区神经元放电频率和兴奋性有关。     

舍曲林抗创伤后应激障碍效应及其对一氧化氮的影响

目的利用大鼠条件性恐惧模型,探讨舍曲林抗创伤后应激障碍(PTSD)作用与一氧化氮(NO)之间的关系。方法采用声音线索配对足底电击对成年雄性SD大鼠造成条件性恐惧应激,第2天进行消退训练。每天实验前1 h,ig给予舍曲林15 mg·kg-1,连续8 d。消退训练后第1,4和7天,分别测试大鼠僵住行为。第7天测试完成后取杏仁核,Griess法检测NO含量,Western蛋白印迹法检测神经型一氧化氮合酶(n NOS)与诱导型一氧化氮合酶(i NOS)表达水平。结果行为学结果显示,与正常对照组相比,消退对照组和消退训练组僵住不动时间均显著增高(P<0.01),提示大鼠条件恐惧造模成功。大鼠恐惧消退训练后第1和4天,舍曲林15 mg·kg-1组僵住不动时间均低于消退训练组(P<0.05);在第7天,显著低于消退训练组(P<0.01),提示舍曲林减轻了恐惧反应。舍曲林15 mg·kg-1组大鼠杏仁核区NO含量、n NOS和i NOS表达水平明显低于消退训练组(P<0.01)。结论舍曲林能促进条件恐惧记忆的消退,在条件恐惧模型上具有抗PTSD效应,其作用机制可能与抑制NO过度释放有关。     

日研究人员弄清脑内“消除恐惧感觉”机制

大麻成分会推动突触发挥作用，使基底核活跃起来，从而消除恐惧感觉或记忆。 日本研究人员日前宣布，他们在利用小鼠进行的实验中，弄清了脑内“消除恐惧感觉”的机制，这一成果将有助开发治疗创伤后应激障碍的药物。     

急性应激障碍向创伤后应激障碍发展小鼠模型的制备

目的 制备急性应激障碍(ASD)向创伤后应激障碍(PTSD)发展的小鼠模型,为应激障碍机制研究和防治药物评价提供动物模型.方法 雄性C57BL/6J小鼠,每日足底电击,电流0.8 mA,每次持续10 s,间隔时间10 s,重复15次,连续电击3 d,同时设正常对照组.急性期行为学实验于足底电击后第1～第3天进行;慢性期...     

圣·约翰草提取物片对创伤后应激障碍模型小鼠恐惧和焦虑行为的改善作用

目的研究圣·约翰草提取物片(ESJWT)对短暂电击所致创伤后应激障碍(PTSD)模型小鼠行为的影响,并探讨ESJWT防治PTSD的可能性。方法 48只雄性C57BL/6小鼠随机分为正常对照组、模型组、舍曲林(15 mg·kg-1)和ESJWT(25 mg·kg~(-1))治疗组,每组12只;除正常对照组外其余各组小鼠连续2 d给予不可逃避的足底电击(0.8 mA,持续10 s,间隔10 s,每天15次),实验前1 h药物处理组小鼠分别ig给予盐酸舍曲林和ESJWT,每天1次,持续18 d。第3,8和15天测量小鼠僵住时间百分比和粪便量,于第16,17和18天依次对小鼠进行旷场实验、高架十字迷宫实验和爬梯实验。行为学实验结束后用ELISA测定小鼠血清去甲肾上腺素(NE)和5-羟色胺(5-HT)含量。结果与正常对照组相比,模型组小鼠僵住时间百分比和粪便量显著增加(P<0.01),进入旷场中央区域的次数和时间均显著降低(P<0.01),进入高架十字迷宫开臂的次数和时间均显著降低(P<0.01),爬梯实验中小鼠爬梯次数无显著性差异,但站立次数明显增加(P<0.01),提示PTSD模型制备成功。与模型组相比,舍曲林和ESJWT均能有效改善上述模型小鼠PTSD样行为(P<0.05,P<0.01),其中ESJWT治疗组小鼠在条件恐惧环境下粪便量较模型组显著减少(P<0.01)。各组小鼠血清NE和5-HT含量均无显著性差异。结论 ESJWT可有效改善PTSD模型小鼠的恐惧和焦虑等行为,有可能用于PTSD治疗。     

吗啡不同剂量和给药时程对建立大鼠条件性位置偏爱模型的影响

目的：比较吗啡不同给药剂量及不同给药时程对建立大鼠条件性位置偏爱（cPP）模型的影响，用于建立满意的CPP模型。方法：分别采用15mg／kg吗啡连续颈背部皮下注射（SC）6d，10mg／kg吗啡连续颈背部皮下注射（SC）6d、8d、10d进行CPP训练，测定大鼠在伴药箱停留的时间。结果：与对照组比较，15mg／kg吗啡6d组、10mg／kg吗啡8d组和10mg／kg吗啡10d组大鼠在伴药箱停留的时间均明显延长（P〈0．05），诱导大鼠CPP建立，三组大鼠在伴药箱停留时间比较差异无统计学意义；10mg／kg吗啡训练大鼠6d后，与相应的生理盐水对照组比较，大鼠在伴药箱停留时间差异无统计学意义，未能诱导CPP形成。结论：大鼠在用10mg／kg吗啡训练8d、10d及15mg／kg吗啡训练6d后，均可诱导大鼠CPP形成，但10mg／kg吗啡训练8d建立的CPP模型较满意。     

单程延迟性应激诱导雌性大鼠创伤后应激障碍模型的建立

目的 采用雌性SD大鼠建立单程长时应激(SPS)模型,从表观效度和预测效度2方面考察其是否能作为创伤性应激障碍的动物模型。方法 雌性大鼠依次连续给予固定束缚(2 h)、强迫游泳(20 min)和乙醚麻醉各1次作为应激因子制备SPS模型,随后连续2周内每天1次ig 给予舍曲林10 mg·kg^-1。2周后给予足底电击刺激,次日环境重现,测定呆滞行为时间;高架十字迷宫实验测定进入开臂次数百分比和开臂滞留时间百分比;开场实验观察爬格次数和站立次数。结果 与正常对照组比较,模型组大鼠呆滞行为时间明显延长(P<0.01),进入开臂次数百分比和开臂滞留时间百分比显著降低(P<0.01);与模型组相比,舍曲林组大鼠呆滞行为时间显著降低,进入开臂次数百分比和开臂滞留时间百分比显著增加(P<0.05, P<0.01); 各组爬格次数和站立数与正常对照组无显著性差异。结论 通过SPS成功诱导建立雌性大鼠创伤性应激障碍动物模型。     

Systemic administration of polyaminergic agents modulate fear conditioning in rats

Rationale The polyamines putrescine, spermine, and spermidine are a group of aliphatic amines that physiologically modulate the N-methyl-d-aspartate (NMDA) receptor, a glutamate receptor implicated in memory formation. Objectives Given the potential application of these drugs in the treatment of memory disorders, we investigated whether agonists and/or antagonists of the NMDA receptor polyamine binding site alters the memory of fear conditioning and determined the time window in which fear conditioning is modulated by polyaminergic agents given by the systemic route. Results Post-training intraperitoneal administration of spermidine (10–100 mg/kg) immediately after training increased, whereas arcaine (10 mg/kg) and MK-801 (0.01–0.1 mg/kg) decreased contextual and auditory fear conditioning. Arcaine and MK-801, at doses that had no effect per se, reversed the facilitatory effect of spermidine. Memory of fear conditioning was impaired by polyaminergic blockade up to 180 min but not at 360 min after training. Conclusion These results provide evidence that systemic administration of polyamine binding site ligands modulate early consolidation of fear conditioning.     

The role of group I metabotropic glutamate receptors in acquisition and expression of contextual and auditory fear conditioning in rats - a comparison

Glutamatergic neurotransmission in the CNS plays a predominant role in learning and memory. While NMDA receptors have been extensively studied, less is known about the involvement of group I metabotropic glutamate receptors in this area. The purpose of the present study was to evaluate the contribution of mGluR1 and mGluR5 to both acquisition and expression of behaviours in contextual and auditory fear conditioning models. The effects of both receptor types were tested using selective antagonists: (3-ethyl-2-methyl-quinolin-6-yl)-(4-methoxy-cyclohexyl)-methanone methanesulfonate (EMQMCM) for mGluR1, and [(2-methyl-1,3-thiazol-4-yl)ethynyl]pyridine (MTEP) for mGluR5. Their effects on acquisition were compared to those of the NMDA receptor antagonist (+)MK-801, and the unselective muscarinic antagonist scopolamine, while diazepam and citalopram served as reference compounds in the expression experiments. EMQMCM (1.25 to 5 mg/kg) impaired acquisition of contextual fear conditioning (CFC), but not auditory fear conditioning (AFC). Similarly, administration of MTEP during the acquisition phase impaired learning in CFC at doses of 2.5 to 10 mg/kg, but was ineffective in AFC. When given before the retention test, both EMQMCM (1 and 3 mg/kg) and MTEP (3 mg/kg) impaired expression of CFC. In contrast, MTEP (2.5 and 5 mg/kg) blocked the expression of AFC, while EMQMCM was ineffective. In conclusion, group I mGlu receptors are shown to be involved in the acquisition of hippocampus-dependent CFC, but not hippocampus-independent AFC. Unlike mGluR5, mGluR1 does not seem be involved in expression of AFC.     

脊髓损伤模型的制备及行为学评分

目的：通过对模型的制备模拟脊髓损伤,研究其病理生理变化及脊髓组织的病理分析,为后期的干细胞治疗提供了实验信息。方法：8周龄小鼠,咬除T12～L1棘突及相应椎板,用纤维剪刀将脊髓右侧剪断,将分离的肌肉缝合封闭椎管缺损,缝合皮肤,制成脊髓损伤模型。分不同的时间行为学评分,8周后病理检测。结果：假手术组在不同时间行为学评分较高,而实验组评分很低。脊髓损伤区出现明显的病理改变。结论：实验组与对照组相比具有显著差异且脊髓损伤区域出现胶质细胞增生、嗜神经现象等,从而为进一步研究脊髓损伤提供了较为可靠的模型。     

Characterizing the nature of emotional-associative learning deficits in panic disorder: An fMRI study on fear conditioning,extinction training and recall

Emotional-associative learning represents a translational model for the development, maintenance and treatment of anxiety disorders such as panic disorder (PD). The exact nature of the underlying fear learning and extinction deficits however, remains under debate. Using a three-day paradigm to separate the distinct learning and consolidation processes, we aimed to gain insights into the neurofunctional substrates of altered fear conditioning, extinction training and recall in PD. In contrast to studies employing one-session fear conditioning paradigms, a differential fear conditioning and delayed extinction task was conducted for the purpose of disentangling neural networks involved in fear acquisition, extinction training and recall of extinction memories. Using functional magnetic resonance imaging (fMRI), quality-controlled datasets from 10 patients with PD and 10 healthy controls were available from three consecutive days (day 1: acquisition; day 2: extinction training; day 3: extinction recall) with neutral faces serving as CSs and an aversive auditory stimulus (panic scream) as US.PD patients showed heightened fear circuitry (e.g. right amygdala and left insula) activation during early acquisition and prolonged activation in the right insula, left inferior frontal operculum and left inferior frontal gyrus during extinction recall compared to healthy controls.Stronger neural activation in structures conferring defensive reactivity during early acquisition and extinction recall may indicate the accelerated acquisition of conditioned responses, while extinction recall may be attenuated as a function of PD pathophysiology. Future studies should investigate the predictive value of experimental measures of extinction recall for clinical relapse.     

Effect of paroxetine on enhanced contextual fear induced by single prolonged stress in rats

Rationale Single prolonged stress (SPS) is an animal model of posttraumatic stress disorder (PTSD) that can reproduce enhanced hypothalamo-pituitary-adrenal negative feedback.Objectives We examined whether SPS can produce an enhanced psychophysiological reactivity to laboratory stressors unrelated to trauma and whether paroxetine (PRX) can alleviate the enhanced anxiety and fear response in rats subjected to SPS. Furthermore, the effect of PRX on pain sensitivity was examined in rats with and without SPS.Methods Rats were subjected to SPS (restraint for 2 h, forced swim for 20 min, and ether anesthesia) and then kept undisturbed for 14 days. After that, contextual fear response was assessed. Twenty-four hours after foot shock conditioning, freezing behavior was measured during reexposure to the shock environment for 3 min. Pain sensitivity was assessed by the flinch–jump test. PRX (0.01, 0.03, or 0.1 mg/mL) was chronically administered orally in drinking water.Results Rats subjected to SPS showed a significant increase in contextual freezing compared to rats without SPS. Chronic administration of PRX at concentrations of 0.03 and 0.1 mg/mL (which produced serum concentrations similar to those that are clinically relevant) caused significant suppression of the enhanced contextual freezing. Acute administration of PRX at a dose producing clinically relevant serum concentrations did not affect the enhanced freezing.Conclusions Our results suggest that SPS can reproduce behavioral alteration similar to that observed in patients with PTSD, and this elevated fear response can be alleviated by the chronic administration of PRX at doses producing clinically relevant serum concentrations.     

Evaluation of a psychophysiological model of classical fear conditioning in anxious patients

Skin conductance variables have been compared in 30 anxious patients and 30 controls to investigate the extent to which anxiety is associated with increased autonomic arousal, reduced habituation or enhanced aversive conditioning. Skin conductance level, variability (spontaneous fluctuations) and response amplitudes to tones were significantly greater in patients than controls. Habituation of skin conductance responses to a series of ten innocuous tones (80 dB, 1 s) did not differ between the groups. Aversively conditioned skin conductance responses were measured to a further series of ten tones after a conditioning trial in which a loud white noise (100 dB) followed tone 11. All subjects showed enhanced (conditioned) responses to the tones after the conditioning trial, but patients did not show greater conditioning than controls. The results indicate that anxious neurotic out-patients have greater sweat gland activity and reactivity than controls but fail to demonstrate differences in central mechanisms of habituation or conditioning.     

Effect of chronic treatment with the protein kinase C inhibitor staurosporine on the acquisition and expression of contextual fear conditioning

The present study investigated the effects of acute and chronic administration of the protein kinase C inhibitor, staurosporine, on the acquisition and expression of conditioned freezing behavior, an index of anxiety induced by conditioned fear stress. Results revealed that acute staurosporine (0.01 and 0.1 mg/kg, i.p.) did not affect either acquisition or expression of conditioned freezing. Chronic staurosporine administration (0.01 or 0.1 mg/kg, i.p., for 14 days) significantly reduced the acquisition of conditioned freezing at a dose of 0.1 mg/kg, but failed to affect the expression of conditioned freezing at any dose. These results suggest the involvement of protein kinase C in synaptic and cellular plasticity underlying emotional learning and memory.