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21.
Effects of ageing on the total number of muscle fibers and motoneurons of the tibialis anterior and soleus muscles in the rat 总被引:1,自引:0,他引:1
The age-related changes in the total number of muscle fibers and motoneurons of the tibialis anterior and soleus muscles were studied using 10-, 65-, and 135-week-old rats. The number of fast twitch muscle fibers was decreased at age 65 weeks, while the numbers of slow twitch fibers and of alpha motoneurons were decreased only later, at age 135 weeks. Therefore, the degenerative process of muscle fibers differs with the fiber type. 相似文献
22.
The involvement of dopamine (DA) receptor subtypes in the behavioral effects of CNS stimulants was studied in rats trained to discriminate occaine from saline. In substitution tests, the stimulus effects of 10mg/kg of this substance generalized tod-amphetamine (0.25–1.0 mg/kg) and the selective D2 against LY-171555 (0.05–0.25 mg/kg); but not to the D1 agonist SKF-38393 (5.0–15.0 mg/kg); in combination tests, the D1 antagonist Sch-23390 (0.0625–0.5 mg/kg) significantly blocked, and the D2 antagonist spiperone (0.25–0.5 mg/kg) partially blocked the cocaine cue. These data suggest that the involvement of DA systems in the behavioral effects of cocaine is more complex than either D1
or D2 receptor activation; for example, the stimulus properties of this substance might involve both D1
and D2 receptor activation.Some of these results were presented at the meeting of the Society for Neuroscience, Toronto, 1988 相似文献
23.
2-乙氧基乙醇急性染毒大鼠血清和睾丸某些抗氧化指标的变化 总被引:1,自引:0,他引:1
目的 观察2-乙氧基乙醇(2-Ethoxythanol,EE)急性染毒对SD大鼠血清和睾丸某些抗氧化指标的变化,探讨EE致睾丸损伤的可能机制。方法 选择健康雄性SD大鼠,体重180-220g。随机分为对照组、EE800、1600和3200mg/kg组4组,每组24只。采取一次性灌胃染毒。于灌胃后12、24、48和72h,将各组动物随机处死6只,留取动物血液、睾丸,制备血清和睾丸匀浆,测定血清和睾丸匀浆脂质过氧化物(LPO)水平、超氧化物歧化酶(SOD)活性、过氧化氢酶(CAT)活性,以及血清铜蓝蛋白(CP)活性。结果 与对照组比较,各染毒组睾/体比明显下降(P<0.05),睾丸匀浆LPO水平和血清CP活性增高。染毒12、24h,血清CAT、睾丸匀浆CAT和SOD活性增高,而染毒48、72h后,血清CAT、睾丸匀浆CAT和SOD活性显著降低(P<0.05)。EE各染毒组血清LPO水平和SOD活性变化不明显。结论 推测EE毒作用的靶器官可能是睾丸,睾丸抗氧化功能的改变是EE致睾丸毒性的可能机制。 相似文献
24.
25.
用外耳道外沿皮下缝合法制备了一种新的单侧听觉气传导持续阻滞大鼠模型。它具有制作简便、损伤较小、效果持续的优点。 相似文献
26.
不同脑缺血和再灌流过程中大鼠脑组织NO含量的动态变化 总被引:12,自引:0,他引:12
采用线栓法制成大鼠大脑中动脉梗塞 ( MCAO)模型 ,依 Hb O2 - NO法测定持续性脑缺血和缺血 /再灌流脑组织内 NO含量的变化 ,以探讨不同脑缺血和再灌流过程中 NO的变化规律及其意义。结果 :缺血 3小时受损脑组织 NO水平即增高 ,再灌流后 NO逐步升高 ,而持续性缺血状态下 NO则表现降低后再升高的变化。虽然两组 NO在 7天时均有明显降低 ,但仍高于缺血前水平。认为持续性脑缺血和缺血 /再灌流情况下 NO的变化规律有所不同 ,与缺血脑组织的缺氧及产生 NO所需底物供应缺乏有关 ,且可能与脑组织的损害密切相关 相似文献
27.
大鼠下丘脑弓状核的形态计量研究 总被引:1,自引:1,他引:0
为了探讨急性癫痫弓状核形态改变与可复性,我们采用光、电镜技术和形态计量方法对下丘脑弓状核进行了形态定量研究。结果显示:弓状核切面面积为317500±6460um2,神经元胞体和胞核的等效直径分别为12.94±0.34um和8.54±0.43um,暗细胞内线粒体、粗面内质网、高尔基复合体、溶酶体、游离核相体和分泌颗粒的面积分数分别是5.87±1.98%、3.53±0.25%、0.81±0.49%、2.13±0.42%、10.53±0.46%和0.86±0.35%,其面数密度(单位面积为30um2)分别为15.68±1.14um-2、21.29±3.52um-2、10.20±0.42um-2、5.62±067um-2、101.35±7.55um-2和5.22±0.77um-2.本文还对弓状核的形态结构、神经元类型及其功能进行了讨论。 相似文献
28.
JOSEPH ROCHFORD ANANDA P SEN ISABELLE ROUSSE SHARON A WELNER 《Brain research bulletin》1996,41(5):313-317
Latent inhibition (LI) is a reduction in the rate of acquisition of a Pavlovian conditioned response that results from prior nonreinforced preexposure to a conditioned stimulus (CS). LI has been suggested to reflect the operation of mechanisms involved in stimulus selection for subsequent cognitive processing. The present experiment was conducted to assess the effect of bilateral lesions of the nucleus basalis magnocellularis (NBM) on LI employing a conditioned emotional response paradigm. Bilateral lesions of the NBM were produced by administration of 0.12 M quisqualic acid and resulted in decreased cortical acetylcholinesterase staining, as well as a 40% reduction in cortical choline acetyltransferase activity. Following lever press training, preexposed animals received 40 presentations of a 60-s tone CS. Nonpreexposed animals received no tone presentations. Acquisition of conditioned suppression was then assessed over the course of 4 tone-shock (0.6 mA, 0.5 s) pairings. Control, preexposed animals displayed a retarded rate of acquisition in comparison to nonpreexposed controls, thereby demonstrating that the parameters used in the present experiment produced LI. In contrast, lesioned animals preexposed to the CS acquired conditioned suppression as readily as non-preexposed lesioned animals. However, the acquisition of conditioned suppression in both lesioned groups was found to be similar to that displayed in the preexposed control group. This pattern of results was interpreted as being attributable to a lesion-induced impairment in the ability to maintain stimulus processing, rather than a deficit in the ability to filter a stimulus. Copyright © 1996 Elsevier Science Inc. 相似文献
29.
Jordi Llorens Cristina Su ol Josep M. Tusell Eduard Rodrí guez-Farr 《Neurotoxicology and teratology》1990,12(6):607-610
The inhibition of [35S]t-butylbicyclophosphorothionate ([35S]TBPS) binding to the GABAA receptor by the insecticide γ-hexachlorocyclohexane, lindane, was studied in several brain regions and using different membrane preparation methods, both in vitro and after dosing the animals with the chemical. In the latter studies, the amount of lindane remaining in the membrane suspensions used for binding assays was determined. In vitro data showed values of IC50 from 150 to 1675 nM, varying in function of the membrane preparation method used. This may account for the discrepancies in IC50 values found in the literature. IC50 values within the range of 150–250 nM were determined using extensively washed membranes from several brain regions, so no evidence arose for brain regional differences in the affinity of lindane for the TBPS binding site. After different schedules of acute treatment with lindane, we found a manifest relationship between the extent of the observable inhibition of [35S]TBPS binding and the lindane amount remaining in the membrane suspensions used for binding assays. This relationship was in good agreement with the in vitro data, so no support for an in vivo acute regulation of the binding site was obtained. 相似文献
30.
Minerva Giménez y Ribotta Christelle Roudet Françoise Sandillon Alain Privat 《Brain research》1996,707(2):245
The synaptic connections established by grafted noradrenergic (NA) neurons into the lesioned adult rat spinal cord were analysed using immunocytochemistry at the electron microscopic level. An embryonic cell suspension of the locus coeruleus region from E-13 rat embryos was transplanted into the spinal cord following either: (1) spinal cord transection or (2), partial selective denervation by 6-hydroxy dopamine (6-OH DA). One month after grafting, the NA-neurons established, in the two models, an innervation pattern similar to that found in the intact spinal cord. In both models, the transplanted NA-immunoreactive neurons formed extensive synaptic contacts with dendrites, spines and perikarya. The proportion of axodendritic and axospinous contacts was inverse in the two models. The first model thus reproduced more closely the normal synaptic pattern prefering dendritic targets, which could correspond to a better integration of the graft. In the second model, a partially NA-denervated spinal cord, there existed a competition between residual intrinsic and grafted neuron-derived fibres, which presumably affects synaptogenesis. In conclusion, the present study illustrate the complexity of cell interations conducting to the formation of a specific circuitry. Recognition phenomenon are likely modulated by space constraints, which ultimately shape-up the geometry of synaptic contacts. 相似文献