宫内暴露可卡因和胎鼠发育:不同给药剂量和给药时间的比较

目的　在妊娠期可卡因总给药剂量相等的情况下 ,探讨不同的给药时间及单次给药剂量对胎鼠发育的影响。方法　实验动物分为盐水对照组 (SAL)、可卡因小剂量组(COC2 0 )和可卡因中等剂量组 (COC4 0 )。妊娠 (Embryonicday ,E) 17d取材 ,记录各组胎鼠体重、脑重、纹状体重。并采用HPLC结合电化学检测器的方法测定各组胎鼠纹状体中多巴胺 (dopamine ,DA)和 5 羟色胺 (serotonin ,5 HT)的浓度。结果　COC4 0和COC2 0组胎鼠体重、脑重、纹状体重均低于SAL组 ;然而 ,仅COC4 0组胎鼠的脑 /体重比低于SAL组 (P <0 0 1)。HPLC结果表明 ,COC4 0、COC2 0组胎鼠纹状体DA、5 HT含量均高于SAL组 ,且COC4 0组纹状体 5 HT的含量显著高于COC2 0组。结论　与妊娠中晚期接触小剂量的可卡因相比 ,妊娠中期中等剂量接触可卡因对中枢神经系统发育的影响明显大于对胎鼠整体发育的影响     

妊娠中晚期接触可卡因对小鼠胎儿神经系统发育的影响

目的　观察妊娠母体接触可卡因引起的胎儿神经系统发育异常 ,研究宫内暴露可卡因引起的胎儿发育迟缓是否与母体孕期营养不良有关以及胎儿神经系统发育异常与神经递质的变化之间的关系。方法　小鼠妊娠d 8(E8)到d 17(E17) ,每日 2次颈背部皮下注射盐酸可卡因 2 0mg·kg-1·d-1,同时建立饮食对照组和盐水对照组 ,每日 2次注射生理盐水 2 0ml·kg-1·d-1,在此期间记录各组母鼠、胎鼠生理指标。E17取材 ,用HPLC法检测给药组血中可卡因浓度及各组母鼠、胎鼠纹状体多巴胺 (dopamine ,DA)、5 羟色胺 (sero tonin ,5 HT)的浓度。结果　可卡因给药组 (COC)与盐水对照组 (SAL)相比 ,母体体重增长量及总摄食量均减少 ,纹状体多巴胺和 5 羟色胺含量增高 (COCn =16 ,SALn =11,P<0 0 1) ;胎鼠体重、脑重、纹状体重也存在明显差异 (SALn=76 ,COCn =92 ,P <0 0 1)。而可卡因给药组与饮食对照组 (SPF)相比 ,在母鼠摄食量相等、体重增长量无明显差异 (COCn =16 ,SPFn =12 ,P >0 0 1)的情况下 ,胎鼠的各项生理指标均下降 (COCn =92 ,SPFn =6 5 ,P <0 0 1) ,且脑纹状体多巴胺、5 羟色胺水平明显升高 ,分别为 (88± 12 )ng·g-1,(2 4 2± 18)ng·g-1。结论　宫内暴露可卡因可引起子代神经系统发育异常 ,这种发育异常?     

宫内暴露于可卡因的仔鼠脑功能的可塑性研究

目的：建立妊娠中晚期接触可卡因的小鼠动物模型，探讨脑功能的可塑性现象和机制。方法：测量可卡因处理组与对照组仔代小鼠在青春期和成年期的体重与脑重；运用高效液相色谱结合电化学检测器技术（High porformance liquid chromatography-electochemistry,HPLC-EC)检测各仔鼠各时期脑内多巴胺（dopamine,DA)及其代谢产物3，4－双羟苯乙酸（3，4－dihydroxyphenylacetic acid,DOPAC)、高香草酸（4-hydroxy-3-menthoxyphenylacetic acid,HVA)的含量，同时检测各时期仔鼠再次接触可卡因脑内DA、DOPAC和HVA的变化。结果：有可卡因宫内接触史的仔鼠在青春期体重和脑重比对照组仔鼠下降，脑内DA及其代谢产物含量增高，上述变化在成年期恢复正常。各组仔鼠在生后青春期再次接触可卡因后DA及其代谢产物含量均升高，此时可卡因处理组仍比对照组含量高，在成年期各组仔鼠再次接触可卡因虽DA及其代谢产物虽也升高，但无组间差异。结论：妊娠中晚期暴露于可卡因可以引起仔鼠脑多巴胺能神经系统功能的改变，这种改变随脑发育的不断完善而正常，即具有可塑性，并且这种塑性同样适用于静息和应激两种状态下。     

溴氰菊酯对发育大鼠脑NOS活性及神经行为的影响

目的　探讨溴氰菊酯 (deltamethrin ,DM)对发育大鼠脑内一氧化氮合酶 (nitricoxidesynthase ,NOS)活性及神经行为发育的影响。方法　将妊娠大鼠随机分为对照组和两个剂量组 ,妊娠第 1天～ 19天隔日 1次DM经口染毒 ,剂量分别为 0、3 3 5和 6 70mg kg。观察DM对妊娠 2 0d胎鼠、5、10和 2 1日龄仔鼠脑NOS活性及 3 0日龄仔鼠学习和记忆能力的影响。结果　 6 70mg kgDM染毒组 1、5和 10日龄仔鼠体重明显下降 ;产后 5d～ 2 1d仔鼠脑NOS活性呈发育性增高趋势 ;两个剂量组 5日龄雄性仔鼠及 6 70mg kgDM染毒组 5日龄雌性仔鼠脑NOS活性明显高于对照组 (P <0 0 5 ) ,而妊娠2 0日龄胎鼠、10与 2 1日龄仔鼠脑NOS活性未见明显变化 ;行为试验结果显示 :6 70mg kgDM染毒组仔鼠延迟时间为(3 86± 1 40 )s、被动逃避反应阳性率为 2 4% ,与对照组 [(1 68± 0 70、6% ) ]相比 ,差异有显著性 (P <0 0 5 )。两个剂量DM染毒组仔鼠旷场试验中行进格子数均明显降低 ,与对照组相比 ,差异均有显著性 (P <0 0 5 )。结论　母鼠妊娠期接触DM可影响仔鼠脑内NOS活性 ,并造成仔鼠神经行为发育迟缓     

可卡因对后代多巴胺能神经系统的长时影响:剂量依赖性与年龄依赖性研究

目的　通过建立妊娠中晚期暴露于可卡因的小鼠动物模型 ,探讨可卡因对后代多巴胺能神经系统 (dopaminergicnervoussystem ,DAS)的发育是否具有长时程影响 ,同时探讨这种影响是否具有剂量依赖性和年龄依赖性。方法　称量不同剂量可卡因处理组与对照组的后代仔鼠在青春前期、青春期和成年期的体重和脑重 ;运用高效液相色谱结合电化学检测器 (HPLC EC)的技术检测各组各时期后代仔鼠脑内多巴胺 (dopamime,DA)及其代谢产物 3 ,4 双羟苯乙酸 (3 ,4 di hydroxyphenylaceticacid ,DOPAC)、高香草酸 (4 hydroxy 3 menthoxyphenylaceticacid ,HVA)含量差异 ;通过免疫组织化学结合图像分析方法观察黑质区 (substantianigra,SN)酪胺酸羟化酶 (tyrosinehydroxylase,TH)的分布与含量。 结果　在妊娠期中晚期皮下注射中等剂量可卡因的仔鼠在青春前期和青春期生长发育延迟 ,脑内DA及其代谢产物的含量比对照组明显增高 ,SN区TH相对含量增多 ,这些改变在成年期恢复正常 ;低剂量组的仔鼠各项检测指标在各时期与对照组相比无统计学意义 ;高剂量组的妊娠母鼠流产率为 80 % ,新生仔鼠 1 0d内死亡。结论　妊娠期暴露于可卡因对后代DAS的发育和功能具有长时程影响 ,这种影响具有剂量依赖性和年龄依赖性     

胚胎小鼠肾脏发育中神经型一氧化氮合酶的定量分析

目的:探讨神经型一氧化氮合酶在胚胎小鼠妊娠不同时期肾脏发育中的意义。方法:选用成年健康昆明小白鼠,按雌雄比例3:1同窝饲养,采用检查阴道栓脱落的方法确定雌鼠受孕时间。选取胚龄12天(ED12)、14天(ED14)、16天(ED16)、18天(ED18)的胎鼠及出生时(PD0)仔鼠,分5组,每组各6只母鼠,每只母鼠取2只胎鼠或仔鼠,剖腹取肾脏,用免疫印迹技术(Westernblot)及光密度分析系统分别对各组胎鼠或仔鼠肾脏内nNOS进行定量检测。结果:Western blot及光密度分析显示,ED14组肾脏nNOS含量最少,随后逐渐增多,PD0组肾脏nNOS含量最多。结论:胚胎小鼠肾脏nNOS在胚胎第14天开始呈阳性表达,以后含量逐渐升高,出生时含量最高,表明nNOS在胚胎小鼠肾脏发育的早期阶段起重要作用。     

低水平铅暴露对仔鼠白细胞78kd糖调蛋白表达的影响

目的 通过建立低水平铅暴露模型,研究宫内和哺乳期低水平铅暴露对仔鼠白细胞葡萄糖调节蛋白78(glucose regulated protein 78,GRP78)蛋白表达量的影响,从内质网应激的角度探讨铅的发育免疫毒性.方法 将母鼠孕0天至仔鼠出生21天分成不同时期对仔鼠进行低水平铅暴露,用原子吸收分光光度法测定血铅含量,用Western印迹法检测白细胞内质网GRP78蛋白表达量.结果 3个染铅组血铅含量均明显高于对照组,哺乳组的白细胞中GRP78蛋白表达量明显高于对照组,有显著性差异.结论 哺乳期低水平铅暴露可使仔鼠白细胞内质网上的GRP78蛋白应激性表达增加而表现出发育免疫毒性,内质网上的GRP78是铅的重要蓄积库.     

孕鼠铅暴露对仔鼠血铅水平影响的研究

目的探讨孕鼠铅暴露对仔鼠血铅水平的影响。方法wistar大鼠42只,雌雄各半,按雌雄配对分为五组（A、B、C、D、E）。A组为正常对照组,进食正常饲料B、C、D、E组每公斤饲料分别添加醋酸铅0．3g,0．9g,2．7g,8．1g,产仔后恢复正常饲料。母鼠与仔鼠组a—e1、2于生后1、3周分别进行血铅测定。结果仔鼠血铅水平与母鼠血铅水平呈正相关（r=0．517）。结论胎鼠血铅水平与母鼠孕期铅暴露的程度相关。     

维生素E对2,3,7,8-四氯二苯并二噁英致大鼠死胎及胚胎发育迟缓的影响

目的研究维生素E对2,3,7,8-四氯二苯并二噁英(TCDD)致大鼠死胎及胚胎发育迟缓的影响。方法 60只妊娠Wistar大鼠分成5组,在妊娠的第6~15天,连续给予TCDD和维生素E的水平依次为:空白对照组、TCDD50 ng/kg和维生素E 0 mg/kg、TCDD 50 ng/kg和维生素E 50 mg/kg、TCDD 50 ng/kg和维生素E 100 mg/kg、TCDD50 ng/kg和维生素E 200 mg/kg。于妊娠第20天处死孕鼠,解剖观察,计数着床数,活胎数、吸收胎、死胎数,称取子宫重量,胎仔重,量取胎仔的身长及尾长。结果 50 ng/kg TCDD可显著降低平均活胎数,增加吸收、死胎率,并且引起胎鼠发育迟缓,体重、身长和尾长均显著低于对照组。而维生素E可显著降低TCDD对大鼠活胎数的影响,减少吸收、死胎率,缓解胎鼠发育迟缓。结论本实验初步证明TCDD能够降低大鼠活胎数,提高死胎率,使胚胎发育迟缓,而维生素E对其具有拮抗作用。     

甲基汞的行为致畸效应

目的　探讨胚胎期甲基汞暴露对大鼠仔代的行为致畸效应。方法　 3月龄Ｗｉｓｔａｒ雌性大鼠受孕后随机分为 4组 ,采用甲基汞 (0 0 0、0 0 1、0 0 5、2 0 0ｍｇ·ｋｇ- 1 ·ｄ- 1 )于妊娠 6～9ｄ灌胃染毒。 2 8只孕鼠妊娠 19ｄ时进行传统致畸试验。 2 4只孕鼠自然分娩 ,观察 2 0 1只仔鼠出生后的早期神经行为发育 ;79只仔鼠出生 7周时进行迷宫测试 ;32只仔鼠出生 10周时进行自动化操作行为测试。分娩 5周的 2 4只母鼠及出生10周的 2 4只仔鼠进行脑组织检查。结果　胚胎期甲基汞暴露对大鼠的母体毒性十分微弱 ;但低剂量就对胎仔体重及尾长…     

Increased vulnerability to self-administer cocaine in mice prenatally exposed to cocaine

RATIONALE: At least 40,000 infants born each year in the U.S. are estimated to have been exposed to crack cocaine and, therefore, may be at risk for increased vulnerability to cocaine addiction. OBJECTIVES: The present study tested the hypothesis that prenatal exposure to cocaine significantly increased subsequent cocaine-taking behavior in mice. METHODS: Swiss Webster male mice that had been exposed to cocaine in utero were tested at 5 months of age in the cocaine self-administration paradigm. They were the offspring of dams that received one of the following treatments during gestation days 8-17: cocaine (40 mg/kg or 20 mg/kg per day; COC40 and COC20 mice, respectively), saline with access to food ad libitum (SAL mice), or saline with access to food restricted to that of the COC40 dams (i.e., pair-fed; SPF40 mice). Mice were initially trained to lever press for a condensed-milk solution, were implanted with an indwelling intravenous (i.v.) catheter and, subsequently, allowed to self-administer cocaine (0.25, 0.5, 1.0, or 2.0 mg/kg per injection) under a fixed ratio (FR) 1 schedule of reinforcement. RESULTS: Latency for acquisition of food-reinforced responding appeared to be independent of prenatal treatment, as was acquisition of cocaine self-administration, which was found to be dose dependent. Both COC40 and SAL mice reached cocaine self-administration criteria at 1.0 mg/kg or 2.0 mg/kg per injection doses, while neither group did so at lower doses. It was also observed that, at each of the doses tested, a higher number of COC40 mice reached criteria for acquisition. A logistic regression analysis confirmed that the likelihood for acquiring cocaine self-administration was positively correlated to prenatal exposure to cocaine and the dose of cocaine tested. CONCLUSIONS: These data provide evidence, for the first time, that prenatal exposure to higher doses of cocaine increase the probability of acquiring cocaine self-administration at moderate doses during adulthood and modulate vulnerability to cocaine-taking behavior in mice.     

Attenuation of cocaine-induced genomic and functional responses in prenatal cocaine-exposed rabbits.

The effects of in utero cocaine exposure on cocaine-induced genomic and functional responses in postnatal life were examined. Pregnant Dutch Belted rabbits were injected intravenously, twice daily, with cocaine hydrochloride (4 mg/kg) or saline from day 8 through day 29 of pregnancy. Prenatally exposed kits were challenged with cocaine on postnatal day 20. In prenatal saline-exposed kits, cocaine induced time- and dose-dependent c-fos gene expression in both frontal cortex and striatum. Prenatal cocaine exposure reduced cocaine-induced c-fos responses by 35-58% in the frontal cortex and 37-41% in the striatum. Cocaine-induced functional responses that included head bobbing, seizure, and locomotor activity were also attenuated in prenatal cocaine-exposed kits. Cocaine-induced c-fos expression and functional responses were blocked by the D(1) dopamine receptor antagonist, SCH23390, or by the serotonin receptor antagonist, methysergide, but not by the D(2) dopamine receptor antagonist, L-sulpride. The results indicate that in utero cocaine exposure leads to diminished responses to cocaine challenge in the offspring, which may be mediated by prenatal cocaine-induced alterations in one or more components of the D(1) dopamine and/or serotonin receptor signaling systems during early postnatal life.     

Fetal and maternal brain and plasma levels of cocaine and benzoylecgonine following chronic subcutaneous administration of cocaine during gestation in rats

The distribution of cocaine and the cocaine metabolite benzoylecgonine (BE) in brain and plasma of Sprague-Dawley rat dams and their near-term fetuses was assessed 0.5 and 2 h post-injection on gestational day 20 following chronic daily subcutaneous injections of 10, 20, or 40 mg/kg/3 ml cocaine hydrochloride beginning on gestational day 8. Plasma concentrations of cocaine reached in the dams were found to be in the range of, or to exceed, those reported in human cocaine users. Dose-related increases in plasma and brain levels of cocaine in the dams and the fetuses were observed, particularly at 2 h post-injection. Fetal concentrations of cocaine in brain and plasma were approximately 2–3-fold less than those of the dams, suggesting that the placenta may somewhat restrict cocaine entry into fetal circulation. Brain/plasma cocaine ratios, however, were generally equivalent in the dams and fetuses, suggesting that once cocaine enters the circulation, its affinity for brain tissue is similar in the fetus and dam. Whereas plasma levels of BE, like cocaine levels per se, were greater in the dams than fetuses, BE concentrations in fetal brain were greater than those observed in maternal brain. These high levels of BE may contribute to the production of neurobehavioral alterations in cocaine-exposed offspring, given that this active cocaine metabolite has been shown to form molecular complexes with calcium ions (Misra and Mule 1975), thereby having the potential to influence a multiplicity of calcium-regulated developmental events. Taken together, the results of the present study suggest that the subcutaneous route may prove to be an appropriate means in rats for administering cocaine prenatally in investigations designed to assess potential neurobehavioral ramifications of gestational cocaine exposure.     

Prenatal exposure to cocaine. I: Effects on gestation, development, and activity in Sprague-Dawley rats.

Sperm-positive Sprague-Dawley rats received one of four treatments for 20 days beginning within 24 hours of conception. One group received subcutaneous injections of 15 mg/kg cocaine twice daily (Cocaine-D); a second group received 15 mg/kg cocaine twice daily for two consecutive days at 5-day intervals (Cocaine-I); a third group received normal saline twice daily (Saline); and a fourth group received 1.5 mg/kg amfonelic acid (AFA), a dopamine reuptake inhibitor, once daily. Cocaine-D, Cocaine-I, and AFA dams were fed ad lib. An attempt was made to pair-feed the Saline dams with the Cocaine-D dams; however, the Saline dams did not eat as much as the Cocaine-D dams which resulted in dams in all groups essentially eating ad lib. The Cocaine-D pups showed a slightly delayed righting behavior and neophobia at 30 days of age, as evidenced by hypoactivity during the first 15 min of a 6-h activity test. The Cocaine-I pups were hypoactive during the 3-h dark phase of the 6-h activity test when tested at 30 days of age. These effects did not occur in the offspring exposed to AFA, a potent dopamine uptake inhibitor and CNS stimulant which indicate that one or more other sites for cocaine action may combine for its effects on the developing fetus.     

Prenatal cocaine alters dopamine and sigma receptor binding in nucleus accumbens and striatum in dams and adolescent offspring

Maternal cocaine abuse is a societal problem with serious impact on both mother and child. Few studies exist that study the mother/offspring dyad of neurological effects of maternal cocaine abuse. The present study was designed to study alterations in D2, D3 and sigma receptor density in nucleus accumbens and striatum of dams and male and female offspring following gestational cocaine. Long-Evans female rats were implanted with an intravenous (i.v.) access port prior to breeding and were administered saline or 3.0 mg/kg of cocaine from gestational day (GD) GD8-20 (1 injection/day-GD8-14, 2 injections/day-GD15-20). Offspring were raised by maternal dams and allowed to mature until postnatal days 31-35, at which time dams and offspring were sacrificed for assay of radioligand binding. In dams, decreased D2 (24.6%) and D3 (36.9%) binding was observed in striatum. Female offspring displayed no differences in receptor binding in either region. Male offspring displayed decreased D2 receptor binding (27.1%) in nucleus accumbens and increased D3 (75.2% and 33.5%) and sigma receptor binding (73.4% and 53.1%) in accumbens and striatum, respectively. Collectively, these data clearly demonstrate that male offspring exhibit significant alterations in D2, D3 and sigma receptor binding. These results suggest that dams and offspring display long-lasting alterations (5 weeks) in dopamine receptor binding. These alterations in dopamine and sigma receptor binding in offspring following prenatal cocaine and rearing by maternal dams are sex specific and could have profound effects on the development of behavior.     

A preliminary investigation of the effects of maternal ethanol intake during gestation and lactation on brain adenosine A(1) receptor expression in rat offspring

Ethanol exposure during fetal development can result in behavioral and neurological deficits, including reduced cognitive functions, retarded growth, and craniofacial abnormalities. Adenosine is an endogenous neuromodulator that fine-tunes the release and/or synaptic activities of several neurotransmitters, including glutamate, dopamine, and serotonin. Our aim was to determine whether ethanol exposure during early development affects adenosine receptors, particularly the A1 receptor subtype, in adult rats. Female rats were given water or 15% (vol/vol) ethanol in water prior to mating and throughout gestation and lactation. Sixty-day-old male rat offspring from these dams were randomly selected and assayed for adenosine A1 receptor expression in four brain areas: cortex, cerebellum, hippocampus, and striatum. Our results indicate that ethanol intake by dams decreased body and brain weights of offspring and reduced both A1 receptor mRNA and protein density in cortex and cerebellum. These preliminary findings indicate that ethanol intake by dams during pregnancy and lactation can affect adenosine A1 receptor signalling in the offspring. A pair-fed controlled study is warranted to explore these findings further.