Attenuation of scopolamine-induced amnesia in mice

The dose-response effects of the substituted xanthine 8-cyclopropyltheophylline (CPRT) on sleep and wakefulness (W) after intraperitoneal administration to rats were examined by means of simultaneous electroencephalographic (EEG) and electromyographic (EMG) recordings. Doses of 20 and 40 mg/kg CPRT increased W and decreased slow wave sleep (SWS) in rats, indicating CNS stimulant effects. The greatest CNS stimulation was produced by the lowest (20 mg/kg) dose of CPRT examined, which also increased the latency to SWS. In addition, the 20 mg/kg dose of CPRT also significantly decreased the amount of total sleep (TS), as compared to the vehicle group, during all time periods examined. In contrast, the 80 mg/kg dose of CPRT decreased W and increased both SWS and TS. However, this apparent hypnotic effect of the 80 mg/kg CPRT may be due to toxicity, since 80% of rats treated with this dose of the drug died within 48 h of injection.     

Attenuation of dysfunction in the ischemia-reperfused liver by glycyrrhizin.

The present study evaluated the effect of glycyrrhizin (GR) on an injury of the liver caused by ischemia-reperfusion in rats. In the liver ischemia-reperfusion model, levels of serum GOT, GPT and LDH activities and lipid peroxides in the liver tissue were significantly increased. On the contrary, total glutathione content in the liver tissue and NADPH cytochrome P-450 reductase activity of liver microsomes were decreased. Pretreatment with GR 20 mg/kg, i.v. 10 min before induction of ischemia resulted in significant decreases in serum GOT, GPT, LDH activities and the lipid peroxide level and a higher tissue glutathione content during the period of reperfusion. Electron microscopic studies revealed various hepatocellular damages with an almost intact sinusoidal endothelium in ischemia-reperfused livers. However, the degree of damage was less severe in the livers from the rats pretreated with 20 mg/kg GR. The results indicate that GR is able to provide partial protection against ischemia-reperfused damage.     

梓醇改善东莨菪碱诱导的学习记忆障碍及机制研究

目的研究梓醇对由东莨菪碱所致小鼠空间学习记忆障碍的影响和机制。方法小鼠随机分为4组:正常组、模型组(东莨菪碱,2 mg.kg-1)、奥拉西坦组(阳性药物,105mg.kg-1)和梓醇治疗组(9 mg.kg-1),采用水迷宫测试小鼠空间学习记忆功能。于实验前30 min腹腔注射东莨菪碱诱导小鼠学习记忆障碍模型,记录小鼠逃避潜伏期时间。水迷宫测试毕,处死小鼠,分离大脑皮质和海马,匀浆取上清液测大脑皮质和海马中乙酰胆碱(acetylcholine,ACh)和脑源性神经营养因子(brain-derived neurotrophic factor,BDNF)的含量。结果①各组实验前逃避潜伏期无差异;给药东莨菪碱前后差异有显著性。②组间比较,与正常组比较,东莨菪碱导致记忆障碍;与东莨菪碱组比较,阳性药物奥拉西坦和梓醇治疗组逃避潜伏期明显缩短,ACh和BDNF含量明显增加(P<0.05)。结论小鼠注射东莨菪碱成功诱导学习记忆机能障碍模型。梓醇改善东莨菪碱诱导的学习和记忆障碍,其机制可能与促进BDNF表达,增加脑ACh含量有关。     

Ondansetron and arecoline prevent scopolamine-induced cognitive deficits in the marmoset.

The cognitive-enhancing potential of the 5-hydroxytryptamine (5-HT) selective 5-HT3 receptor antagonist, ondansetron, was investigated in a model of cognitive impairment induced by the muscarinic receptor antagonist, scopolamine. For this purpose, marmosets were trained in an object discrimination task utilizing the Wisconsin General Test Apparatus. Administration of scopolamine (0.01-0.04 mg/kg, SC) caused a dose-dependent impairment in the acquisition of the object discrimination task in that marmosets required more trials to reach criterion, made more errors, and took longer to choose the objects. Administration of arecoline (0.06-0.1 mg/kg, SC) or 1,2,3,9-tetrahydro-9-methyl-3-[(2-methyl-1H-imidazol- 1-yl)methyl]-4H-carbazol-4-one,HCl.2H2O (ondansetron) (0.1-1 micrograms/kg, SC) prevented the scopolamine-induced impairment in task acquisition in that the performance of marmosets was indistinguishable from that of saline-treated animals and was significantly better than that following scopolamine/saline. From these studies, we conclude that ondansetron prevents impairment in the cognitive performance of marmosets induced by administration of scopolamine.     

油酰乙醇胺对东莨菪碱诱导小鼠认知功能损伤的保护作用

目的 探讨油酰乙醇胺对东莨菪碱诱导小鼠认知功能损伤的保护作用。方法 将小鼠随机分为6组：对照组、模型组、多奈哌奇组（阳性药,3 mg·kg^-1）和油酰乙醇胺低、中、高剂量（50、100、200 mg·kg^-1）组,每组6只。在ig给药4周后,除对照组外,各组ip 3 mg·kg^-1的东莨菪碱建立阿尔茨海默病（AD）模型。避暗、跳台行为学实验检测小鼠记忆功能; ELISA法检测小鼠海马和大脑皮层中乙酰胆碱（Ach）和乙酰胆碱酯酶（AChE）水平;HE染色观察小鼠大脑皮层及海马损伤。结果 与对照组比较,模型组的避暗潜伏期显著缩短、避暗错误次数显著增加（P<0.001）;大脑皮层、海马的Ach水平显著减少（P<0.01、0.001）,AChE活性显著升高（P<0.001）;模型组的小鼠脑组织形态结构不均匀,组织细胞呈弥散状,提示组织存在病变。与模型组比较,各给药组的避暗潜伏期显著升高、避暗错误次数显著减少（P<0.01）;油酰乙醇胺给药组的小鼠大脑皮层、海马组织Ach水平显著升高（P<0.05、0.01）,AChE活性显著降低（P<0.01、0.001）;小鼠脑组织形态结构病理改变减轻。结论 油酰乙醇胺对东莨菪碱诱导学习记忆障碍模型小鼠的认知功能具有改善作用,其作用机制可能与调节胆碱能系统功能、促进神经细胞存活有关。     

Synthesis and anti-platelet activity of obovatol derivatives

Obovatol derivatives were synthesized and evaluated for anti-platelet activity. Three derivatives (1, 2, 4i) displayed equipotent activity to obovatol in arachidonic acid-induced platelet aggregation. An initial SAR study revealed that the introduction of alkoxy group in B ring could enhance inhibitory activity.     

深化对认知功能障碍的认识

认知功能障碍已成为影响中老年人健康和生活质量的重要疾病.早期干预可延缓患者认知功能的衰退及精神和行为症状的发展,有助于维持患者基本的认知功能,改善患者及其照料者的生活质量.本文对阿尔茨海默病及其他认知功能障碍的研究进展作一综述.     

RU 41 656 does not reverse the scopolamine-induced cognitive deficit in healthy volunteers

Summary The potential antagonism of a single oral dose of RU 41 656 10 mg on the memory and attention disturbances induced by scopolamine 0.6 mg s.c. have been investigated in a 3 period, placebo controlled, double blind, cross over study in 12 healthy, young volunteers.The effects of the compounds were evaluated by objective tests (Buschke selective reminding test, CFF, simple reaction time, tapping, arithmetical calculation) and subjective measurements (visual analogue scale, side effects questionnaire). Measurements were taken before treatment and 2, 4 and 7 h after RU 41 656.Scopolamine caused anterograde amnesia and sedative effects as which were not counteracted by RU 41 656.     

Attenuation of contractile dysfunction by atorvastatin after intestinal ischemia reperfusion injury in rats

Growing number of studies implicate that 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, or statins, have beneficial effects on ischemia/reperfusion injury that are unrelated to their cholesterol-lowering action. In the present study, we aimed to evaluate possible effects of atorvastatin on oxidative stress, neutrophil accumulation, and contractile response of terminal ileum segments in rats subjected to intestinal ischemia/reperfusion. Intestinal ischemia/reperfusion model was generated by clamping the superior mesenteric artery for 30 min followed by reperfusion for 3 h. Oral administration of atorvastatin at a dose of 10 mg/kg/day lasted 3 days just before induction of intestinal ischemia. At the end of reperfusion period, terminal ileum samples were removed to determine the concentrations of malondialdehyde, reduced glutathione, and myeloperoxidase. Samples were collected also to assess histopathological alterations and contractile response to agonists. Ischemia/reperfusion significantly decreased contractile responses, and this decrease was attenuated by atorvastatin. Pretreatment with atorvastatin caused remarkable decrease in both oxidative stress and neutrophil accumulation. Atorvastatin appeared to be restoring amount of reduced glutathione back to about control level. Furthermore, the pretreatment lowered mucosal damage at histopathological level. Our results suggested that pretreatment with atorvastatin attenuated intestinal muscle dysfunction associated with ischemia/reperfusion. This remarkable effect of atorvastatin is accomplished at least by decreasing oxidative stress and neutrophil accumulation as well as preventing the depletion of reduced glutathione.     

The effects of pre-treatment with enalapril maleate on scopolamine-induced cognitive deficits in healthy volunteers

Two studies were undertaken to investigate the effects of acute (Study 1) or repeated (Study 2) administration of the angiotensin converting enzyme (ACE) inhibitor enalapril on the cognitive deficits produced by scopolamine administration in volunteers. Enalapril at doses between 2.5 and 10.0 mg p.o. produced virtually complete blockade of plasma ACE activity. However, it did not influence the effects of scopolamine on a variety of cognitive tasks, including tests of memory, attention and sedation.     

Reversal of reserpine-induced orofacial dyskinesia and cognitive dysfunction by quercetin

Tardive dyskinesia (TD) is a serious neurological syndrome associated with long-term administration of neuroleptics to humans and experimental animals. The pathophysiology of this disabling and commonly irreversible movement disorder is still obscure. It may be caused by a loss of dopaminergic cells or may be due to free radicals as a product of high synaptic dopamine levels. Quercetin is a bioflavonoid with strong antioxidant properties. Repeated treatment with reserpine (1.0 mg/kg) on each other day for a period of 5 days (days 1, 3 and 5) significantly induced vacuous chewing movements (VCMs) and tongue protrusions (TPs) in rats. Chronic treatment with quercetin for a period of 4 weeks to reserpine-treated animals significantly and dose dependently (50 and 100 mg/kg) reduced the reserpine-induced VCMs and TPs. Reserpine-treated animals also showed poor retention of memory in elevated plus-maze task paradigm. Chronic quercetin administration significantly reversed reserpine-induced retention deficits. Biochemical analysis revealed that chronic reserpine treatment significantly induced lipid peroxidation and decreased the glutathione (GSH) levels in the brains of rats. Chronic reserpine-treated rats showed decreased levels of antioxidant defense enzymes, superoxide dismutase (SOD) and catalase. Chronic administration of quercetin dose dependently (50-100 mg/kg) and significantly reduced the lipid peroxidation and restored the decreased GSH levels by chronic reserpine treatment. It also significantly reversed the reserpine-induced decrease in brain SOD and catalase levels in rats. The results of the present study clearly indicated that quercetin has a protective role against reserpine-induced orofacial dyskinesia and memory impairment. Consequently, the use of quercetin as a therapeutic agent for the treatment of TD should be considered.     

Nicotinic treatment for cognitive dysfunction

Nicotinic medications may provide beneficial therapeutic treatment for cognitive dysfunction such as Alzheimer's disease, schizophrenia and attention deficit hyperactivity disorder (ADHD). For development of nicotinic treatments we are fortunate to have a well characterized lead compound, nicotine. Transdermal nicotine patches offer a way to deliver measured doses of nicotine in a considerably safer fashion than the more traditional means of administration, tobacco smoking. We have found that transdermal nicotine significantly improves attentional function in people with Alzheimer's disease, schizophrenia or ADHD as well as normal nonsmoking adults. To follow-up on this proof of principal that nicotinic treatment of cognitive dysfunction holds promise, it is important to use animal models to determine the critical neurobehavioral bases for nicotinic involvement in cognitive function so that more selective nicotinic analogues that improve cognitive function with fewer side effects can be developed. We have found with local infusion in rat studies that the hippocampus and amygdala are important substrates for nicotinic effects on working memory function. Both alpha7 and alpha4beta2 nicotinic receptors are involved in working memory. Nicotinic interactions with dopaminergic and glutaminergic systems are also important in the basis of cognitive function. Studies of the neural nicotinic mechanisms underlying cognitive function are key for opening avenues for development of safe and effective nicotinic treatments for cognitive dysfunction.     

Antidepressants in states of cognitive dysfunction

Several approaches are described for the design of pharmacologic strategies for the manipulation of cognition. By a variety of criteria, it is concluded that antidepressants deserve a trial in some patients with cognitive dysfunction. Depression is an illness with prominent cognitive dysfunction that shares, to some extent, cognitive and biochemical impairments similar to those observed in cognitive dysfunction of organic etiology. Antidepressants appear to produce their beneficial effect on cognition in depression by inducing slow adaptive changes in catecholamine and indoleamine pathways, therein promoting alterations in the individual's central motivational state. Animal data supporting these ideas are reported. As reviewed, few satisfactory studies of antidepressants in cognitive dysfunction of organic etiology appear in the literature, perhaps as the result of the potent anticholinergic properties of the most popular antidepressant drugs.     

Reversal of scopolamine-induced amnesia by phosphatidylserine in rats

Scopolamine (2 mg/kg IP) and propranolol (55 mg/kg IP), given before a single learning trial, reduce retention of a passive avoidance response in rats. Phosphatidylserine, 30–60 mg/kg IP, antagonizes the amnesic effect of scopolamine but not that of propranolol. The retention of the passive avoidance response is not affected by phosphatidylserine given alone. The results indicate that this phospholipid selectively counteracts the action of scopolamine on passive avoidance acquisition, probably via a cholinergic mechanism.     

术后认知功能障碍的研究进展

术后认知功能障碍(Postoperation cognitive dysfunction,POCD)是指患者在手术及麻醉后出现的认知功能下降,在老年人群的发病率较高。其发病机制目前还不明确,但普遍认为,年龄、手术以及麻醉是POCD发生的主要危险因素。研究证实,许多麻醉药物都能够提高POCD的发病率。POCD还没有诊断的"金标准",现在主要依靠比较手术前后患者的认知功能改变诊断,其中简易精神状态量表(Mini mental state examination,MMSE)和一系列神经心理试验是应用最广泛的测试方法。     

Attenuation by nitrosothiol NO donors of acute intestinal microvascular dysfunction in the rat.

1. The effects of the nitric oxide (NO) donors, S-nitroso-glutathione (SNOG) and S-nitroso-N-acetyl-penicillamine (SNAP), on the acute intestinal microvascular dysfunction induced by NG-nitro-L-arginine methyl ester (L-NAME) in combination with low doses of endotoxin were investigated in the anaesthetized rat. 2. Administration of L-NAME (5 mg kg-1, s.c.) concurrently with E. coli lipopolysaccharide (LPS, 3 mg kg-1, i.v.) provoked the leakage of radiolabelled albumin in the ileum and colon, as a measure of microvascular damage, determined 1 h after challenge. 3. Intravenous infusion of SNOG or SNAP (1-10 micrograms kg-1 min-1) dose-dependently attenuated the microvascular leakage induced by L-NAME and LPS. 4. Infusion of the lowest doses of SNOG or SNAP (1 microgram kg-1 min-1, i.v.) that significantly reduced the albumin leakage, did not affect the increase in blood pressure in response to L-NAME in LPS-treated rats. Higher doses of SNOG or SNAP (5-10 micrograms kg-1 min-1, i.v.) dose-dependently reduced this increase in blood pressure. 5. In control studies, intravenous infusion of glutathione (10 micrograms kg-1 min-1) or N-acetyl-penicillamine (10 micrograms kg-1 min-1) had no effect on microvascular leakage in the ileum and colon induced by LPS and L-NAME. 6. Pretreatment with rabbit anti-rat neutrophil serum (0.4 ml kg-1, i.p., 4 h before challenge), which reduced the neutrophil count in peripheral arterial blood, also inhibited the microvascular leakage in the ileum and colon.(ABSTRACT TRUNCATED AT 250 WORDS)     

新型胆碱酯酶抑制剂双（7）—他克林减弱东莨菪碱引起的大鼠空间记 …

目的 研究他克林的双体衍生物双（７）－他克林对东莨菪碱引起的大鼠记忆障碍的影响。方法 采用大鼠Ｍｏｒｒｉｓ水迷宫固定平台的程序研究空间记忆,以他克林为对照药。结果;东莨菪碱（０．３ｍｇ．ｋｇ＾－１,ｉｐ）使大鼠到达平台的潜伏期明显长于生理盐水对照组,双（７）－他克林（０．３５μｍｏｌ．ｋｇ＾－１,ｉｇ或ｉｐ）和他克林（８．５２μｍｏｌ．ｋｇ＾－１ｉｇ,４．２６μｍｏｌ．ｋｇ＾－１ｉｐ）和他克林（８     

高血压致认知功能障碍机制进展

随着社会、经济和医学的发展,人们的寿命得以延长,与老龄化相关的巨大挑战是脑血管病及认知功能损害两大疾病明显增多,给病人、家庭和社会带来负担。高血压是认知障碍的重要影响因素之一,高血压通过损害脑微循环的结构和功能完整性,破坏血脑屏障,引发神经炎症影响认知功能,以及长期高血压引起的脑小血管病包括白质高信号、腔隙性梗死和微出血,也会导致认知能力下降。目前多项研究表明适当的降压治疗在一定程度上能预防或延缓高血压病人的认知功能障碍。