Dopamine transporter binding in the rat striatum is increased by gestational, perinatal, and adolescent exposure to heptachlor.

Heptachlor is a persistent cyclodiene pesticide that affects GABAergic function. Recent reports indicate that heptachlor exposure also alters dopamine transporter (DAT) expression and function in adult mice. The aim of this study was to determine whether gestational, perinatal, and/or adolescent heptachlor exposure in rats altered dopamine-receptor and DAT binding. Adolescent exposure to dieldrin was included to evaluate the generality of the findings. Sprague-Dawley rats received doses (po) ranging from 0 to 8.4 mg/kg/day of heptachlor, or dieldrin, 3 mg/kg/day, during different developmental periods. There were dose-related decreases in maternal weight gain and pup survival, as well as delayed righting reflex, at heptachlor doses > or =3 mg/kg/day. There were no changes in striatal dopamine receptor-D1 ([(3)H]SCH-23390) and -D2 ([(3)H]spiperone) binding in preweanling pups exposed perinatally to heptachlor, and no differences in the response of adult rats to the motor activity-increasing effects of d-amphetamine. However, there were significant (27-64%) increases in striatal DAT binding of [(3)H]mazindol in preweanling rats exposed only gestationally. In rats exposed perinatally and/or during adolescence, there were also increases (34-65%) in striatal DAT binding at postnatal days (PND) 22, 43, and 128. Adolescent exposure to dieldrin also increased DAT binding. In other rats exposed perinatally and throughout adolescence, even the lowest dose of heptachlor 0.3 mg/kg/d increased DAT binding on PND 130. The DAT affinity for mazindol was unchanged in heptachlor-exposed striata. In vitro binding studies indicated that heptachlor (> or =10 microM) displaced mazindol binding. Thus, gestational, perinatal, and/or adolescent exposure to heptachlor produced an increase in DAT binding as early as PND 10, and this change persisted into adulthood.     

The effects of perinatal/juvenile heptachlor exposure on adult immune and reproductive system function in rats.

This study was performed to determine if developmental exposure of rats to heptachlor (H) during the last half of gestation through puberty adversely affects adult functioning of the immune and reproductive systems. Time-bred pregnant female Sprague-Dawley rats were dosed by gavage with H (0, 30, 300, or 3000 microg/kg/day) from gestation day (GD) 12 to postnatal day (PND) 7, followed by direct dosing of the pups with H through PND 42. Separate groups of rats were evaluated with a battery of immune function tests, while other groups of rats were evaluated for reproductive development and function. Additional groups of rats were euthanized at the end of the dosing period for histological analyses of major organ systems. Some dams and PND 7 pups were euthanized; milk, plasma, fat and/or tissues were assayed for H and heptachlor epoxide B (HEB), a major metabolite of H. The amount of H and HEB found in milk, blood, fat, and tissues was proportional to the dose of H administered. There were no effects on the number or survival of pups born to H-exposed dams nor to pups exposed postnatally. There were no effects on the number of treated dams delivering litters or on litter size, nor were there any effects on any of the reproductive end points examined in the F(0) or F(1) rats. There were no effects of H exposure on lymphoid organ weights, splenic natural killer (NK) cell activity, and splenic lymphoproliferative (LP) responses to mitogens and allogeneic cells in a mixed lymphocyte response (MLR) assay at 8 weeks of age. H exposure did not alter delayed or contact hypersensitivity at 10 or 17 weeks of age, respectively. However, the primary IgM antibody response to sheep red blood cells (SRBCs) was suppressed in a dose-dependent manner in males, but not females, at 8 weeks of age. The percentage of B lymphocytes (OX12(+)OX19(-)) in spleen was also reduced in the high-dose males. The anti-SRBC IgM response was reduced only in males exposed to 30 microg H/kg/day in a separate group of rats 21 weeks of age. In these same rats, at 26 weeks of age, the secondary IgG antibody response to SRBCs was suppressed in all of the H-exposed males, but not females. These data indicate that perinatal exposure of male rats to H results in suppression of the primary IgM and secondary IgG anti-SRBC responses. Suppression of these antibody responses persisted for up to 20 weeks after the last exposure to H, at a total exposure of approximately 1500 microg H/kg/rat.     

甲醛和三氯乙烯联合染毒对小鼠行为功能的影响

目的研究甲醛和三氯乙烯联合染毒对小鼠神经行为的影响,为评价室内装修材料中甲醛和三氯乙烯对人体健康的危害提供科学依据。方法通过Morris水迷宫实验筛选健康清洁级昆明小鼠108只(雌雄各半),按照3×3析因的要求进行随机分组,采用静式吸入染毒,将小鼠暴露于不同浓度的甲醛、三氯乙烯及其二者的混合气体中,每天2 h,连续14 d。染毒结束后,采用Morris水迷宫实验和旷场实验对小鼠进行神经行为学测试。结果 Morris水迷宫实验结果显示,在定位导航实验中,单独及联合染毒组小鼠逃避潜伏期随着训练次数的增多均呈缩短趋势、且随着染毒剂量的增加小鼠逃避潜伏期延长,训练天数、甲醛和三氯乙烯对小鼠逃避潜伏期的影响差异均有统计学意义(P<0.01),同时甲醛和三氯乙烯对小鼠逃避潜伏期的影响存在交互作用(P<0.05)。在空间探索实验中,甲醛和三氯乙烯单独及联合染毒均可致小鼠第一次跨越原平台位置的时间延长。二者联合染毒对小鼠第一次跨越原平台位置的时间和原平台象限游泳距离占总距离百分比的影响存在交互作用(P<0.05),且表现为协同。旷场实验结果显示,甲醛和三氯乙烯染毒致小鼠在中央区活动时间延长,站立次数下降,中央区活动距离占总距离百分比增大,二者对小鼠在旷场实验中的中央区活动时间、直立次数以及中央区活动距离占总距离百分比的影响均有交互作用(P<0.01),且表现为协同。结论甲醛和三氯乙烯能降低小鼠的学习记忆能力,影响神经行为表现,二者联合染毒具有一定的协同作用。     

The effects of perinatal tebuconazole exposure on adult neurological, immunological, and reproductive function in rats.

Studies are under way to address concerns of potential persistent immunotoxic, reproductive, and neurotoxic effects of perinatal exposure to several pesticides. Tebuconazole, a triazole fungicide, was evaluated as part of this project. Sprague-Dawley dams were administered tebuconazole (0, 6, 20, or 60 mg/kg) by oral gavage daily from gestational day 14 to postnatal day (PND)7; the pups were then dosed daily at the same levels from PND7-42. Separate groups of rats were used for testing of immunological parameters, neurobehavioral testing using a screening battery of functional tests, and cognitive evaluations. Other groups of rats were evaluated for reproductive development and function, while yet others were sacrificed at the end of the dosing period for histological analyses of major organs systems, including neuropathological assessments. Pup viability and body weight were decreased in the highest dose group. There were no differences in the fertility indices in the exposed rats mated as adults. In the sheep RBC-immunized high-dose rats, spleen weights and cellularity were increased, and the ratio of cell types was altered compared to controls. There were, however, no biologically significant changes in the immune function of these rats. At necropsy on PND46 or 152, kidney, liver, and spleen weights were altered by tebuconazole treatment, but a dose-response relationship was not clear for most organs; only decreased kidney and increased liver weights were consistent in both sexes. Histological analyses were generally unremarkable outside of the brain. One month after the end of dosing, acquisition of learning the platform location in a water tank (i.e., Morris water maze) was impaired in the high-dose group; there were no differences in neuromuscular ability, motor activity, or swim speed to account for this finding. Furthermore, there was no effect on recall of the position during a free-swim trial. Neuropathological evaluations revealed pyknotic cells across hippocampal cell fields in animals of all tebuconazole treatment groups, with the highest incidence in the 20 and 60 mg/kg/day dose groups, coincident with cell loss within pyramidal cell layer of CA3-4 cell fields of the hippocampus and layer V of the neocortex. Thus, perinatal exposure to tebuconazole produced neurobehavioral deficits and neuropathology in rats, but did not alter immunological or reproductive function.     

Neurobehavioral effects of chronic dietary and repeated high-level spike exposure to chlorpyrifos in rats.

This study aimed to model long-term subtoxic human exposure to an organophosphorus pesticide, chlorpyrifos, and to examine the influence of that exposure on the response to intermittent high-dose acute challenges. Adult Long-Evans male rats were maintained at 350 g body weight by limited access to a chlorpyrifos-containing diet to produce an intake of 0, 1, or 5 mg/kg/day chlorpyrifos. During the year-long exposure, half of the rats in each dose group received bi-monthly challenges (spikes) of chlorpyrifos, and the other half received vehicle. Rats were periodically tested using a neurological battery of evaluations and motor activity to evaluate the magnitude of the acute response (spike days) as well as recovery and ongoing chronic effects (non-spike days). Effects of the spikes differed as a function of dietary level for several endpoints (e.g., tremor, lacrimation), and in general, the high-dose feed groups showed greater effects of the spike doses. Animals receiving the spikes also showed some neurobehavioral differences among treatment groups (e.g., hypothermia, sensory and neuromotor differences) in the intervening months. During the eleventh month, rats were tested in a Morris water maze. There were some cognitive deficits observed, demonstrated by slightly longer latency during spatial training, and decreased preference for the correct quadrant on probe trials. A consistent finding in the water maze was one of altered swim patterning, or search strategy. The high-dose feed groups showed more tendency to swim in the outer annulus or to swim very close to the walls of the tank (thigmotaxic behavior). Overall, dietary exposure to chlorpyrifos produced long-lasting neurobehavioral changes and also altered the response to acute challenges.     

Effects of prenatal rubratoxin-B exposure on behaviors of mouse offspring.

The effects of prenatal rubratoxin-B (RB) exposure on 8 behavioral parameters in JCL:ICR mice were assessed. Pregnant mice were injected intraperitoneally with 0.1 or 0.2 mg/kg/day of RB dissolved in propylene glycol water solution on days 7-9 (Group A) or 10-12 (Group B) of gestation. Controls received the vehicle similarly on days 7-12 of gestation. Before weaning, the offspring of both sexes were examined to test their the surface righting reflex (5 days of age), cliff avoidance response (6 days), negative geotaxis response (7 days), and swimming development (8, 10, and 12 days). After weaning, male animals were examined using the rotarod test (6 weeks of age), the open-field test (7 weeks), the shuttle-box-avoidance-learning test (9 weeks), and the water E-maze test (10 weeks). The preweanling offspring in the 0.2 mg/kg-B group showed significantly lower success rates and longer response times than controls in the cliff-avoidance response. In swimming development, the offspring in the 0.2 mg/kg B group had significantly lower scores than controls for swimming angle at 10 and 12 days of age. The avoidance learning of the mice in all RB-exposed A and B groups was significantly poorer than that of controls. These results indicate that prenatal exposure to RB produced a delay of early response development and impaired learning ability in the offspring of mice exposed to RB during middle pregnancy.     

Developmental exposure to methylmercury alters learning and induces depression-like behavior in male mice.

To investigate the long-term effects of developmental exposure to methylmercury (MeHg), pregnant mice were exposed to at 0.5 mg MeHg/kg/day via drinking water from gestational day 7 until day 7 after delivery. The behavior of offspring was monitored at 5-15 and 26-36 weeks of age using an automated system (IntelliCage) designed for continuous long-term recording of the home cage behavior in social groups and complex analysis of basic activities and learning. In addition, spontaneous locomotion, motor coordination on the accelerating rotarod, spatial learning in Morris water maze, and depression-like behavior in forced swimming test were also studied. The analysis of behavior performed in the IntelliCage without social deprivation occurred to be more sensitive in detecting alterations in activity and learning paradigms. We found normal motor function but decreased exploratory activity in MeHg-exposed male mice, especially at young age. Learning disturbances observed in MeHg-exposed male animals suggest reference memory impairment. Interestingly, the forced swimming test revealed a predisposition to depressive-like behavior in the MeHg-exposed male offspring. This study provides novel evidence that the developmental exposure to MeHg can affect not only cognitive functions but also motivation-driven behaviors.     

Neurobehavioral toxicity study of dibutyl phthalate on rats following in utero and lactational exposure

To investigate the neurobehavioral effects of dibutyl phthalate (DBP), an important endocrine disruptor known for reproductive toxicity, on rodent offspring following in utero and lactational exposure, pregnant Wistar rats were treated with DBP (0, 0.037, 0.111, 0.333 and 1% in the diet) from gestation day (GD) 6 to postnatal day (PND) 28, and selected developmental and neurobehavioral parameters of the offspring were measured. There were no significant effects of DBP on body weight gain of the dams during GD 6–20 or on the pups' ages of pinna detachment, incisor eruption or eye opening. Exposure to 1% DBP prolonged gestation period, decreased body weight in both male and female pups, depressed surface righting (PND 7) in male pups, shortened forepaw grip time (PND 10), enhanced spatial learning and reference memory (PND 35) in male pups. Exposure to 0.037% DBP also shortened forepaw grip time (PND 10), but inhibited spatial learning and reference memory in male pups. Sex × treatment effects were found in forepaw grip time (PND 10), spatial learning and reference memory, and the male pups appeared to be more susceptible than the females. However, all levels of DBP exposure did not significantly alter surface righting (PND 4), air righting (PND 16), negative geotaxis (PND 4 or 7), cliff avoidance (PND 7) or open field behavior (PND 28) in either sex. Overall, the dose level of DBP in the present study produced a few adverse effects on the neurobehavioral parameters, and it may alter cognitive abilities of the male rodent. Copyright © 2009 John Wiley & Sons, Ltd.     

Effects of arsenic exposure from drinking water on spatial memory,ultra-structures and NMDAR gene expression of hippocampus in rats

Epidemiological investigations indicate that chronic arsenic exposure can damage neurobehavioral function in children. The present study was aimed to study the effects of arsenic exposure from drinking water on the spatial memory, and hippocampal ultra-structures and N-methyl-d-aspartate receptor (NMDAR) gene expression in rats. Sprague–Dawley rats were assigned to four groups: rats in control group drank regular water, rats in other groups drank water with final arsenic concentration of 2.72 mg/L (group A), 13.6 mg/L (group B) and 68 mg/L (group C), respectively, for 3 months. The levels of arsenic in blood serum and hippocampus were monitored. Rats were tested in Morris water maze (MWM) for memory status. Samples of hippocampus were collected from two rats in each group for transmission electron microscopic study and the detection of NMDAR expression by RT-PCR. The rats in group C showed a significant delay in hidden platform acquisition. Neurons and endothelial cells presented pathological changes and the expression of NR2A was down-regulated in hippocampus in arsenic exposed rats. Our data indicated that arsenic exposure of 68 mg/L caused spatial memory damage, of which the morphological and biochemical bases could be the ultra-structure changes and reduced NR2A expression in hippocampus.     

Effect of exposure to staphylococcus aureus,particulate matter,and their combination on the neurobehavioral function of mice

Neurotoxicity in Kunming mice caused by Staphylococcus aureus (S. aureus) and Particulate matter (PM) as individual matter and mixtures was studied in this paper. Male Kunming mice were instilled intratracheally with PM at doses of 0.2 mg/mouse and S. aureus at doses of 5.08 × 10⁶ CFU/mouse as individual matter and mixtures two times at 5-day intervals. Morris water maze (MWM) test was performed during the exposure experiment. One day following the exposure experiment, the expression of neurotrophins, neurotransmitters, cholinergic system enzymes, oxidative damage levels, and pro-inflammatory cytokines (TNF-α, IL-1β) in the brain of mice were determined. Combined treatment of PM and S. aureus led to significant increment of escape latency at day 6, 8, and 10. Oxidative stress levels, and pro-inflammatory cytokines were affected significantly by S. aureus and PM as individual matter and mixtures. Meanwhile, Glu contents were increased significantly in S. aureus group, ChAT levels were decreased significantly in PM group, combined treatment of PM and S. aureus led to significant concentration reduction of AChE. Treatment of S. aureus or PM- S. aureus combination also led to significant concentration reduction of BDNF. Results showed that combined treatment of PM and S. aureus induced damage on physique and motor function, as well as impairment on learning and memory capacity of mice. Oxidative damage, abnormal metabolism of neurotransmitters and cholinergic system enzymes, and the alternation of neurotrophins and pro-inflammatory cytokines expression might be the possible mechanisms for PM − S. aureus −induced neurotoxicity.     

Neurotoxicological interactions of a five-pesticide mixture in preweanling rats.

The estimation of risk following exposure to mixtures is an important feature of pesticide risk assessment. Also of concern is the potential for increased sensitivity of the young to pesticide toxicity. We have conducted interaction studies using a mixture of five organophosphorus (OP) pesticides (chlorpyrifos, diazinon, dimethoate, acephate, and malathion) in both adult (published previously) and preweanling rats using a fixed-ratio ray design. In the present study, cholinesterase inhibition and behavioral changes (motor activity, gait, and tail-pinch response) were measured in 17-day-old Long-Evans male rats following acute exposure to the OPs. The ratio of pesticides in the mixture reflected the relative dietary exposure estimates projected by the U.S. Environmental Protection Agency Dietary Exposure Evaluation Model. Dose-response data were collected for each OP alone, which were used (alone or in conjunction with the mixture data) to build an additivity model to predict the effects of the pesticide mixture along a ray of increasing total doses, using the same fixed ratio of components. The mixture data (full ray) were similarly modeled and statistically compared to the additivity model along the ray. Since malathion has been shown to produce synergistic interactions with certain OPs, it was of interest to evaluate the influence of malathion in this study. A second pesticide mixture, without malathion (reduced ray), was tested using the same dose levels of the remaining four OPs. Analysis of the full ray revealed significant greater-than-additive responses for all endpoints. The magnitude of this shift ranged from two- to threefold for estimates of the ED(20) and ED(50). The deviation from additivity was also detected in the reduced ray for all but two endpoints (motor activity and tail-pinch response); however, for all endpoints, the reduced ray was significantly different from the full ray. Thus, greater-than-additive responses were detected in preweanling rats with this OP mixture, and this effect can only partially be attributed to the malathion in the mixture.     

Effects of 5-HT6 receptor antagonism and cholinesterase inhibition in models of cognitive impairment in the rat

Background and purpose:

The beneficial effect of 5-HT₆ receptor antagonism in cognition remains controversial. This study has been undertaken to reassess the cognition enhancing properties of acute vs subchronic treatment with the selective 5-HT₆ receptor antagonist SB-271046 in unimpaired rats, as well as against scopolamine (cholinergic-) or MK-801 (glutamatergic-mediated) deficits.

Experimental approach:

The Morris water maze was used, measuring behaviour acquisition and retention, and swim speed. Other behavioural measures included yawning and motor activity. SB-271046 was given acutely before each trial or subchronically for 7 days before the trials. The AChE inhibitor galanthamine was also used alone or in combination with SB-271046.

Key results:

Subchronic treatment with SB-271046 improved acquisition in the Morris water maze, while the acute treatment only improved retention. Neither acute nor subchronic SB-271046 treatment reversed scopolamine-induced learning deficits. MK-801 induced learning impairment associated with a behavioural syndrome, reversed by acute, but not subchronic, SB-271046 treatment. Interestingly, combined treatment with galanthamine and SB-271046 reversed the scopolamine- or MK-801-induced learning impairments. Subchronic treatment with SB-271046 did not modify motor activity or the increased number of yawns, a cholinergic-mediated behaviour, induced by single administration of SB-271046.

Conclusions and implications:

These data suggest a potential therapeutic role of 5-HT₆ receptor antagonists such as SB-271046, alone or in combination with galanthamine, in the treatment of cognitive dysfunction, such as those seen in Alzheimer''s disease and schizophrenia.     

川芎嗪对大鼠脑损伤后保护作用的研究

目的探讨川芎嗪对大鼠脑损伤后的保护作用。方法将60只大鼠随机分为对照组、损伤组及治疗组,每组20只。损伤组、治疗组以改良Feeney自由落体脑损伤模型方式对大鼠制作脑损伤动物模型,治疗组大鼠在脑损伤后接受川芎嗪治疗。实验第14天应用HE染色、电镜观察及水迷宫实验评价脑损伤对大鼠形态学和学习记忆的影响及川芎嗪的保护作用。结果 HE染色结果显示,应用川芎嗪注射液治疗后,治疗组正常运动神经元数目多于损伤组;电镜下可见治疗组神经细胞核固缩程度、染色质浓染程度、胞浆空泡化较损伤组减轻。水迷宫实验结果显示,治疗组第1次穿过平台时间较损伤组缩短[(7.68±1.09)s vs.(10.15±2.35)s],在靶象限活动时间较损伤组延长[(86.14±16.68)s vs.(62.38±19.67)s],穿过平台次数多于损伤组(6.4±2.3vs.3.8±1.6),差异均有统计学意义。结论川芎嗪治疗可能在脑组织损伤及大鼠学习记忆功能中发挥重要的治疗效应。     

Preliminary investigation of changes in the sexually dimorphic nucleus of the rat medial preoptic area following prenatal exposure to fenitrothion

In vitro, the organophosphate insecticide fenitrothion is a potent competitive androgen receptor antagonist, whereas in vivo it affects the development of the male rat reproductive system. The purpose of this pilot study was to determine whether prenatal exposure to fenitrothion affects development of the rat sexually dimorphic nucleus of the medial preoptic area (SDN-POA). Pregnant rats (n = 5-6 litters/group) were orally dosed with corn oil (vehicle) or fenitrothion (20 or 25 mg kg(-1) day(-1)) from gestation day (GD) 12-21. Offspring were euthanized after reaching sexual maturity (females 60-65 days old and males 96-105 days old) and the SDN-POA volumes determined for two rats/sex/litter. Tremors, increased lacrimation and decreased body weight gain were observed in dams from both fenitrothion exposure groups. Reproductive effects in male offspring, including reduced anogenital distance on postnatal day (PND) 1 and increased retention of areolae (PND 13) were observed following fenitrothion exposure at these dose levels. These effects did not persist into adulthood. There was a dose-related increase in the SDN-POA volume in males and a dose-related decrease in SDN-POA volume in females exposed to fenitrothion. These SDN-POA volume changes contrast with those seen with flutamide, another potent anti-androgen, and suggest that fenitrothion may have mixed endocrine effects on the developing brain.     

Neurochemical effects of repeated gestational exposure to chlorpyrifos in developing rats.

The neurochemical effects in developing rats exposed during gestation to the anticholinesterase organophosphorus insecticide chlorpyrifos (CPS) were determined. Pregnant rats were dosed daily with CPS (0, 3, or 7 mg/kg) in corn oil from gestation days (GD) 6-20. Pups were euthanized on postnatal days (PND) 1, 3, 6, 9, 12, and 30 for the determination of brain cholinesterase (ChE) and choline acetyltransferase (ChAT) activities, along with muscarinic receptor (mAChR) densities, the levels of the high-affinity choline uptake (HACU) system, and the vesicular acetylcholine transporter (VAChT). ChE activities were inhibited about 15 and 30% on PND 1, in the low- and high-dosage groups, respectively, and were not different from control values by PND 6. mAChR densities on PND 1 were reduced in the high-dosage group by about 18, 21, and 17%, using 3H-N-methylscopolamine, 3H-quinuclidinyl benzilate, and 3H-4-DAMP, respectively, as ligands, and were not different from control levels by PND 6. ChAT activity was decreased by approximately 12% in the high-dosage group on PND 9, 12, and 30. HACU levels, using 3H-hemicholinium-3 as the ligand, were reduced by approximately 25% on PND 6 in the low- and high-dosage groups, and by approximately 14 and 21% on PND 12 and 30, only in the high-dosage group. Levels of the VAChT were reduced by a range of 13-31% on PND 3 through 30 in the high-dosage group, using 3H-AH5183 (vesamicol) as the ligand. These data suggest that gestational exposure to 7 mg/kg/day CPS results in long-term alterations of presynaptic cholinergic neurochemistry.     

吡格列酮对脂多糖引起的大鼠学习记忆障碍及海马炎症反应的影响

目的研究吡格列酮(pioglitazone,Pio)能否对抗脂多糖(lipopolysaccharide,LPS)所致的大鼠学习记忆障碍及海马炎症反应。方法取SD大鼠40只,随机分为4组:生理盐水对照组,LPS损伤组,LPS+Pio 40和80 mg.kg-1组。灌胃给予Pio 2 d后,脑室注射LPS 5μl(1.0 mmol·L-1),生理盐水对照组注射等量生理盐水。脑室注射后d 2进行Morris定位航行实验,连续5 d,在d 6进行空间探索实验,训练期间继续给药。d 7,快速取海马CA1区,Western blot方法观察白介素-1β(Interleukin-1β,IL-1β),诱导型一氧化氮合酶(Inducible Nitric Oxide Synthase,iNOS),半胱氨酸天冬氨酸蛋白酶(caspase)3,caspase-9及多聚ADP-核糖聚合酶(PARP)蛋白表达水平的变化。RT-PCR检测IL-1β和iNOS的mRNA表达水平。结果脑室内注射LPS,大鼠出现明显的空间学习记忆障碍,表现为逃避潜伏期较生理盐水对照组明显延长(P<0.05),在原平台象限游泳时间占总游泳时间的百分比明显降低(P<0.01)。Western蛋白印迹及RT-PCR结果显示注射LPS后,与对照组相比海马CA1区IL-1β、iNOS蛋白及mRNA表达水平明显增加(P<0.01),活化的caspase-3,caspase-9蛋白表达水平明显增高,分子质量116 ku PARP表达明显减少,而分子质量89 ku劈切PARP表达明显增加(P<0.01)。Pio(40和80 mg.kg-1)能改善大鼠学习记忆功能,对抗LPS引起的海马CA1区IL-1β、iN-OS、活化的caspase-3、活化的caspase-9表达增加,也可明显抑制LPS所致的PARP表达的改变(P<0.01)。结论吡格列酮能够改善大鼠学习记忆功能,抑制LPS引起的海马炎症反应。     

知母皂苷对脂多糖引起的大鼠学习记忆障碍和炎症反应的影响

目的观察知母皂苷(SAaB)是否对脂多糖(LPS)引起的大鼠学习记忆障碍和炎症反应有改善作用。方法大鼠随机分为对照组、LPS损伤组、LPS+SAaB(20、40mg·kg-1)组。对照组和LPS损伤组大鼠灌胃给予0.2%的二甲基亚砜,SAaB组大鼠灌胃给予SAaB。连续给药7d后,左侧脑室内单次注射LPS30μg/只大鼠,注射量为5μl,正常对照组大鼠注射等量的生理盐水。脑室注射后d2进行大鼠Morris水迷宫实验,连续6d,训练期间继续给药。水迷宫实验结束后,Nissl染色观察海马CA1区锥体神经元改变;白细胞介素-1β(IL-1β)分别与integrinαM和胶质原纤维酸性蛋白(GFAP)双重免疫荧光染色观察IL-1β表达部位;Westernblot检测海马IL-1β、诱导型一氧化氮合酶(iNOS)的表达水平。结果 SAaB(40mg·kg-1·d-1)能明显改善LPS所致大鼠学习记忆能力损伤,表现在明显缩短大鼠的逃避潜伏期,增加大鼠在原平台象限的游泳时间占总游泳时间的百分比;海马CA1区锥体神经元损伤较LPS组明显减轻,对抗LPS引起的IL-1β及iNOS的蛋白表达水平增加;激光共聚焦实验结果显示IL-1β主要在小胶质细胞表达,少量在星形胶质细胞表达。结论 SAaB能改善LPS引起的大鼠学习记忆障碍,抑制其海马的炎症反应。     

大鼠出生前接触苯妥英和褪黑素对仔代反射功能发育及自发运动的影响

目的 :探讨苯妥英 (DPH)神经发育毒性与胚胎脑组织中自由基产生和氧化应激反应的关系。方法 :Wistar孕鼠于妊娠d 11～ 14经 0 ,10 0 ,2 0 0mg·kg-1DPH或合并 4 0mg·kg-1褪黑素 (MT)染毒处理 ,研究MT对DPH的仔代反射功能发育及自发运动损害作用的拮抗效应。结果 :孕鼠在染毒期及染毒后增重下降 ,仔代体重减轻 ,哺乳期死亡率增高 ;DPH染毒仔鼠的转身运动增多 ,空中翻正反射及游泳能力发育延迟 ,成年后行走次数、站立次数、刻板动作等自发活动增多 ,旋转手比率增多 ,对阿朴吗啡“激发”反应性增强。MT和DPH合并处理可明显拮抗上述DPH仔鼠的行为异常。结论 :氧化性损伤在DPH神经发育毒性发生中发挥重要作用 ,而MT可拮抗其毒性作用。     

Neonatal exposure to higher brominated diphenyl ethers, hepta-, octa-, or nonabromodiphenyl ether, impairs spontaneous behavior and learning and memory functions of adult mice.

Polybrominated diphenyl ethers (PBDEs), used as flame retardants, have been shown to be increasing in the environment and in human mother's milk. We have earlier reported that lower brominated PBDEs, such as tetra-, penta-, and hexa-brominated diphenyl ethers, can cause developmental neurotoxic effects in mice. Recently, this was also observed with the full-brominated PBDE, deca-brominated diphenyl ether (PBDE 209), although it was suggested that the effects were caused by a (possibly debrominated) metabolite thereof. The present study revealed that 2,2',3,3',4,4',5,5',6-nonabromodiphenyl ether (PBDE 206), 2,2',3,4,4',5,5',6-octabromodiphenyl ether (PBDE 203), and to a minor extent also 2,2',3,4,4',5',6'-heptabromodiphenyl ether (PBDE 183) can induce developmental neurotoxic effects. Neonatal Naval Medical Research Institute male mice were exposed on postnatal day 3 or 10 to PBDE 206, PBDE 203, or PBDE 183, given as a single oral dose of 21 mumol/kg body weight. At the adult age of 2-3 months, the mice were observed for performance in a spontaneous behavior test and the Morris water maze test. PBDE 203 and PBDE 206, when administered on neonatal day 10, caused disturbances in spontaneous behavior, leading to disrupted habituation and a hyperactive condition in adults at the age of 2 months. These behavioral changes were also seen in 2-month-old mice exposed to PBDE 203 on neonatal day 3. Furthermore, exposure to PBDE 203 on neonatal day 10 affected learning and memory functions in adult mice. The developmental neurotoxic effects were most pronounced in mice exposed to PBDE 203. These developmental neurobehavioral defects were in agreement with those we observed previously with lower brominated PBDEs and with PBDE 209. It is important to consider the fact that different PBDE congeners can have differing degrees of potency, when comparing levels of PBDEs in the environment and in mother's milk.     

Memory-enhancing effect of a cerulein analogue following peripheral administration in the rat

Our previous studies demonstrated that cerulein (CER) has a potent preventive action on amnesia induced by electroconvulsive shock, administration of scopolamine, puromycin, anisomycin, NMDA receptor antagonists, and protein kinase C inhibitors. The present study was aimed at finding more effective CER analogues which could enhance memory processes. Five CER analogues were synthesized and the potencies in passive and active avoidance responses and in the Morris water pool test were examined in the rat. Among the preparations, des-Gln²-[Leu⁵, Nle⁸]-CER was found to possess particularly potent effects on memory acquisition and/or storage. The effects were apparent in less than 1 μg/kg single subcutaneous (s.c.) injection for at least 120 hr in passive avoidance response and 15 days in active avoidance response. Memory impairments induced by scopolamine and puromycin were well improved in passive avoidance response. In the Morris water maze test, disordered behaviors caused by scopolamine and protein kinase C inhibitor were totally restored to the normal state by s.c. injection of this CER analogue. © 1992 Wiley-Liss, Inc.