丁苯酞对脑缺血再灌注损伤大鼠MMP-9活性和血脑屏障通透性的影响

目的探讨丁苯酞对脑缺血再灌注损伤大鼠的保护作用。方法通过线栓法制备大鼠局灶性脑缺血再灌注损伤模型,腹腔注射丁苯酞,于脑缺血再灌注后6h、12h、24h后用免疫组织化学的方法观察损伤侧脑组织MMP-9活性及基底膜成分Ⅳ型(collagenⅣ)胶原表达的变化。同时测定伊文思兰的含量观察损伤侧脑组织血脑屏障通透性。结果随缺血再灌注时间延长,MMP-9活性、EB含量逐渐增加,24h达峰,Ⅳ型胶原的表达逐渐减少,各组之间表达均具有统计学意义(P<0.05);丁苯酞处理组MMP-9活性、EB含量各个时间点明显低于缺血再灌注组,相同时间点Ⅳ型胶原的表达增加(P<0.05)。结论丁苯酞可抑制脑缺血再灌注损伤大鼠MMP-9的表达,增加基底膜Ⅳ型胶原的表达,降低血脑屏障通透性,从而发挥脑保护作用。     

丁苯酞预处理对大鼠脑缺血再灌注损伤的神经保护作用

目的研究丁苯酞预处理对大鼠局灶性脑缺血再灌注损伤的神经保护作用。方法健康成年SD雄性大鼠48只,随机分为假手术组、缺血再灌注组、丁苯酞预处理组,每组各16只。各组均灌胃5d后,采用线栓法制作大鼠局灶性脑缺血再灌注(MCAO)模型,缺血2h、再灌注24h,进行神经功能缺损评分,TTC染色及图像分析观察脑梗死体积,免疫组化法检测脑组织caspase-3、bcl-2表达的变化。结果与缺血再灌注组相比,丁苯酞预处理组神经缺损程度改善,梗死灶体积减少,caspase-3阳性细胞数量减少,bcl-2表达上调。结论丁苯酞可减轻缺血性脑血管病的发作,具有一定的神经保护作用。     

丁苯酞对大鼠脑缺血再灌注损伤后HSP10表达的影响

目的研究丁苯酞干预对大鼠脑缺血再灌注损伤后不同时点脑组织中热休克蛋白10(HSP10)表达的影响,并探讨丁苯酞对缺血性脑血管病保护作用的机制。方法采用夹闭双侧颈总动脉的方法制作大鼠前脑缺血再灌注模型;H&E染色和NSE免疫组化染色神经元,观察脑组织的形态变化和记数各组神经元数目;免疫组织化学检测对照组、缺血再灌注组及丁苯酞干预组大鼠脑组织HSP10的表达水平变化。结果脑缺血再灌注后丁苯酞干预组及缺血再灌注组HSP10表达水平于再灌注后6h开始上调,3d达到高峰,丁苯酞干预组各时间点HSP10阳性表达指数均高于缺血再灌注组,丁苯酞干预组脑组织的损伤程度明显轻于脑缺血再灌注组(P<0.05)。结论丁苯酞可能通过上调大鼠缺血再灌注损伤后脑组织HSP10的表达,从而抑制前脑缺血再灌注损伤后细胞凋亡,减少神经元死亡,减轻缺血再灌注后脑组织的损伤。     

丁苯酞预处理对脑缺血再灌注大鼠内质网应激的影响

目的 探讨丁苯酞预处理对脑缺血再灌注大鼠内质网应激的影响.方法 30只SD大鼠随机分成假手术组、缺血再灌注组、丁苯酞预处理组,每组10只大鼠.丁苯酞预处理组大鼠给予丁苯酞80 mg/kg灌胃,1次/d;缺血再灌注组和假手术组大鼠给予等量生理盐水替代.灌胃7d后,采用Zea Longa法制备大鼠脑缺血再灌注模型.假手术组不插入线栓.采用TTC染色检测脑梗死面积;RT-PCR法测定脑组织葡萄糖调控蛋白78(GRP78) mRNA、C/EBP同源蛋白(CHOP) mRNA的表达.结果 假手术组大鼠脑组织未见梗死灶;丁苯酞预处理组大鼠脑梗死面积明显小于缺血再灌注组(P＜0.05).缺血再灌注组和丁苯酞预处理组大鼠脑组织GRP78 mRNA、CHOP mRNA的表达量明显高于假手术组(均P＜0.05);丁苯酞预处理组大鼠脑组织GRP78 mRNA、CHOP mRNA的表达量明显低于缺血再灌注组(均P＜0.05).结论 丁苯酞可能通过抑制内质网应激而起到脑保护作用.     

丁苯酞对大鼠局灶性脑缺血再灌注损伤后脑程序性凋亡因子-5表达的影响

目的研究丁苯酞对大鼠局灶性脑缺血再灌注损伤后程序性细胞凋亡因子-5表达的影响。方法健康雄性SD大鼠132只,随机分为假手术组、缺血再灌注模型组、缺血再灌注治疗组,后两者再分别分为再灌注6h、24h、48h、3d、7d共5个亚组,每亚组12只。应用大脑中动脉线栓法制作大鼠局灶性脑缺血再灌注模型,治疗组造模成功后即刻给予丁苯酞80mg／（kg·d）灌胃,余各大鼠给予同剂量生理盐水灌胃。在相应时间点评定神经功能缺损评分,TTC染色法测定脑梗死体积,免疫组化法测定缺血脑组织PDCD-5的表达,TUNEL法测定凋亡细胞。结果假手术组未见梗死灶,偶有凋亡细胞,少见PDCD-5的表达;模型组及治疗组均可见梗死灶及凋亡细胞,有PDCD-5的表达;治疗组在对应时间点较模型组梗死灶小,凋亡细胞少,PDCD-5的表达少。结论丁苯酞对局灶性脑缺血再灌注损伤具有保护作用,其机制可能是通过减少PDCD-5的表达抑制细胞凋亡。     

17β-雌二醇对大鼠脑缺血再灌注损伤脑组织HSP70表达的影响

目的观察雌二醇对大鼠脑缺血再灌注损伤脑组织HSP70表达的影响。方法72只大鼠随机分为假手术组(8只)、实验对照组及雌二醇治疗组,后两组又进一步分为局灶性脑缺血2h再灌注及3h、6h、12h、24h再灌注组,每时间点8只。线栓法建立大鼠局灶性脑缺血/再灌注损伤模型,采用石蜡切片HE及免疫组化染色法检测脑组织损伤及HSP70的表达情况。结果假手术组大鼠未见HSP70的表达;雌二醇治疗组的脑组织缺血半暗带区损伤程度较实验对照组明显减轻;随着再灌注时间的延长,治疗组半暗带区皮质HSP70的表达较对照组上调,且呈先上升后下降趋势,在12h为表达高峰;而纹状体区其表达呈进行性下调趋势。结论17β-雌二醇具有减少脑缺血/再灌注损伤的作用,而半暗带区皮质脑保护蛋白HSP70的表达升高可能其是重要机制之一。     

醒脑静联合丁苯肽对脑缺血再灌注损伤后细胞凋亡的影响

目的 观察醒脑静、丁苯酞及二者联合分别对大鼠脑缺血再灌注损伤后神经细胞凋亡及Bcl-2和Bax表达的影响。方法 60只雄性wistar大鼠(250±20)g采用改良线栓法制作脑缺血再灌注损伤模型(Middle cerebral artery occlusion,MCAO),随机分为4组,即模型组、醒脑静组、丁苯酞组、醒脑静联合丁苯酞(联合用药)组,每组又分为6、24、72 h三个亚组; 通过原位末端转移酶标记技术(TUNEL)检测神经细胞凋亡情况,采用免疫组化法观察大鼠脑缺血再灌注各个时间点Bcl-2、Bax的表达水平。结果(1)模型组手术对侧大脑半球偶见凋亡细胞,病灶区可见大量神经细胞凋亡。丁苯酞用药组、醒脑静用药组凋亡细胞数明显减少,醒脑静联合丁苯酞组凋亡细胞数最少(P<0.05);(2)丁苯酞组及联合用药组Bcl-2阳性表达水平较模型组均有提高,联合用药组Bcl-2阳性表达水平在各时间点均最高(P<0.05); 丁苯酞组及联合用药组Bax阳性表达水平较模型组均有降低,联合用药组Bax阳性表达水平最低(P<0.05)。结论(1)醒脑静、丁苯酞及二者联合均可能通过抑制脑缺血再灌注损伤后神经细胞凋亡来实现神经细胞保护作用,其中二者联合效果最佳;(2)丁苯酞可能通过增加脑缺血再灌注损伤大鼠Bcl-2表达,减少Bax表达的方式来减少神经细胞凋亡,从而减轻脑缺血再灌注损伤;(3)醒脑静本身不能对Bcl-2、Bax的表达水平产生影响,但其可能通过增强丁苯酞作用的方式影响Bcl-2、Bax的表达,从而减轻脑缺血再灌注损伤。     

C-fos反义寡脱氧核苷酸部分阻断MCAO大鼠缺血侧皮质内BDNF的表达

用c-fos反义寡脱氧核苷酸侧脑室微量注射和细胞免疫化学等技术和方法,探讨大鼠局灶性脑缺血(MCAO)模型中,即早反应基因c-fos表达与脑源性神经营养因子(BDNF)表达的关系.结果表明,局灶性脑缺血再灌注可引起c-fos和BDNF在缺血侧皮质的大量表达.侧脑室微量注射c-fos反义寡脱氧核苷酸后,脑内BDNF的部分表达明显被阻断,脑缺血损伤加重.提示脑缺血损伤后,脑内BDNF的表达对脑缺血再灌注损伤起一定的保护作用;脑缺血后BDNF的表达可能部分通过c-fos调控.     

丁苯酞对大鼠局灶性脑缺血再灌注损伤后caspase-3表达的影响

目的:观察丁苯酞(NBP)对脑缺血再灌注损伤后的神经保护作用及caspase-3表达的影响。方法:SD大鼠46只随机分成假手术组(n=6)、缺血再灌注组(n=10)、NBP大剂量组(80mg·kg-1,n=10)、NBP中剂量组(40mg·kg-1,n=10)和NBP小剂量组(20mg·kg-1,n=10),采用ZeaLonga法制作局灶性脑缺血再灌注大鼠模型,观察NBP对大鼠脑缺血再灌注后的神经功能症状、组织形态学改变、以及对caspase-3表达的影响。结果:与假手术组相比,缺血再灌注组大鼠出现严重的神经功能缺失症状,光镜下脑组织出现明显的梗死缺血灶,皮质和海马区caspase-3表达增强;与缺血再灌注组比较,NBP治疗组能显著改善大鼠神经功能缺失症状,减少脑组织的梗死缺血损伤,降低caspase-3的表达,其中以NBP大剂量组的神经保护作用最为显著(P<0.001)。结论:NBP对大鼠局灶性脑缺血再灌注损伤具有保护作用,其作用机制可能与抑制caspase-3表达相关。     

舒血宁注射液对脑缺血再灌注大鼠缺血半暗带水通道蛋白1和水通道蛋白9表达的影响

目的观察舒血宁注射液对脑缺血再灌注大鼠额顶叶皮质缺血半暗带(IP)水通道蛋白1(AQP1)和水通道蛋白9(AQP9)表达的影响。方法线栓法制作局灶性脑缺血再灌注大鼠模型(MCAO),随机分为假手术组、模型组、舒血宁注射液防治组和川芎嗪药物对照组。脑缺血2h,分别再灌注1d、3d、7d,采用免疫组化SABC法检测AQP1和AQP9蛋白表达的阳性总面积和平均吸收光密度。结果在缺血侧额顶叶皮质IP,再灌注各时间点,模型组AQP1和AQP9蛋白表达的阳性总面积和平均吸收光密度显著高于假手术组(P0.05或P0.01),舒血宁注射液和川芎嗪药物对照组再灌注1d、3d、7d,AQP1和AQP9蛋白表达的阳性总面积和(或)平均吸收光密度显著低于模型组(P0.05或P0.01)。结论舒血宁注射液能通过抑制AQP1、AQP9蛋白表达,减轻脑水肿,抗脑缺血再灌注损伤。     

Tongue/palate contact for the production of /s/ and /z/

Productions of /s/ and /z/ by ten adult speakers were investigated using the electropalatograph (EPG). The participants, ten speech researchers who spoke English as their first language, recorded productions of /s/ and /z/ in nonsense and real words. The maximum contact frame was used as the point of reference to compare tongue/palate contact for each production. Each speaker had alveolar contact, lateral bracing and most had a midline groove for both /s/ and /z/; however, the array of contacted electrodes was unique for each speaker. The groove widths and lengths ranged from 0-3 electrodes. There was significantly greater alveolar tongue/palate contact for /z/ compared to /s/ in word-initial position, but not in word-final position for the following measures: alveolar palatal contact, medial groove width, medial groove length. However, when measures of total palate contact and centre of gravity were considered, there was a complex interaction between the phonemes /s/ and /z/, coarticulation with the vowel, word position, and word context (real and nonsense words).     

Tongue/palate contact for the production of /s/ and /z/

Productions of /s/ and /z/ by ten adult speakers were investigated using the electropalatograph (EPG). The participants, ten speech researchers who spoke English as their first language, recorded productions of /s/ and /z/ in nonsense and real words. The maximum contact frame was used as the point of reference to compare tongue/palate contact for each production. Each speaker had alveolar contact, lateral bracing and most had a midline groove for both /s/ and /z/; however, the array of contacted electrodes was unique for each speaker. The groove widths and lengths ranged from 0–3 electrodes. There was significantly greater alveolar tongue/palate contact for /z/ compared to /s/ in word‐initial position, but not in word‐final position for the following measures: alveolar palatal contact, medial groove width, medial groove length. However, when measures of total palate contact and centre of gravity were considered, there was a complex interaction between the phonemes /s/ and /z/, coarticulation with the vowel, word position, and word context (real and nonsense words).     

Molecular biology of the GABAA receptor: the receptor/channel superfamily

Complementary DNAs encoding the two subunit types of the brain GABA_A receptor have been cloned, revealing its full protein primary structure¹. In another laboratory, the same point has now been reached for one of the subunits of the spinal cord glycine receptor². It is illuminating to compare these sequences and those of the nicotinic acetylcholine receptor. All of these receptors, in which an ion channel is directly gated by the binding of the transmitter, are deducéd to be members of a receptor superfamily and exhibit some striking common features in their architecture.     

Suppression of the Pb (P1) component of the auditory middle latency response with contralateral masking

OBJECTIVE: In this study, the effects of contralateral noise or speech on middle latency response (MLR) components P(a) and P(b) (P(1) or P50) were studied using high rates clicks in normal hearing awake adult subjects. METHODS: One standard (4.88 Hz) and four jittered click sequences (24.4, 39.1, 58.6, 78.1 Hz) at different mean rates were monaurally presented to ten subjects. The contralateral ears were stimulated with continuous pink noise, recorded speech or no stimulus for control. Overlapping MLR responses to jittered click stimuli were deconvolved using the frequency domain continuous loop averaging deconvolution (CLAD). RESULTS: The recordings show that contralateral noise or speech stimulation suppresses P(b) component greatly at rates around 40 Hz while earlier components (ABR and P(a)) are not significantly affected. The suppression of the P(b) component is about 50% with some latency reduction. CONCLUSIONS: The results show that the P(b) component of the MLR is significantly affected by contralateral stimulus at resonance rates at around 40 Hz. It appears that the contralateral noise obliterates the amplitude enlargement due to resonance effect. SIGNIFICANCE: These findings show that the P(b) is generated very differently from the P(a) component and strongly inhibited by the contralateral ear. These results also explain the previously observed masking of the 40 Hz auditory steady-state responses (ASSR) with contralateral noise.     

Peripheral antinociceptive effect of pertussis toxin: activation of the arginine/NO/cGMP/PKG/ ATP-sensitive K channel pathway

The aim of the present study was to determine the effect of pertussis toxin (PTX) on inflammatory hypernociception measured by the rat paw pressure test and to elucidate the mechanism involved in this effect. In this test, prostaglandin E(2) (PGE(2)) administered subcutaneously induces hypernociception via a mechanism associated with neuronal cAMP increase. Local intraplantar pre-treatment (30 min before), and post-treatment (5 min after) with PTX (600 ng/paw1, in 100 microL) reduced hypernociception induced by prostaglandin E(2) (100 ng/paw, in 100 microL, intraplantar). Furthermore, local intraplantar pre-treatment (30 min before) with PTX (600 ng/paw, in 100 microL) reduced hypernociception induced by DbcAMP, a stable analogue of cAMP (100 microg/paw, in 100 microL, intraplantar), which indicates that PTX may have an effect other than just G(i)/G(0) inhibition. PTX-induced analgesia was blocked by selective inhibitors of nitric oxide synthase (L-NMMA), guanylyl cyclase (ODQ), protein kinase G (KT5823) and ATP-sensitive K(+) channel (Kir6) blockers (glybenclamide and tolbutamide). In addition, PTX was shown to induce nitric oxide (NO) production in cultured neurons of the dorsal root ganglia. In conclusion, this study shows a peripheral antinociceptive effect of pertussis toxin, resulting from the activation of the arginine/NO/cGMP/PKG/ATP-sensitive K(+) channel pathway.     

Synthesis of the complement factors C3 and C4 within the central nervous system over the course of aseptic meningitis

The concentrations of complement factors C₃ and C₄ were quantified by single radial immunodiffusion in unconcentrated cerebrospinal fluid (CSF) and in serum from 38 patients up to 2 months after onset of acute aseptic meningitigs (AM). Elevated absolute concentrations were found in CSF in 26 and 35 patients, respectively, and in serum in 8 and 31, respectively. Elevation of the CSF C₃ index, equal to (CSF/serum C₃):(CSF/serum albumin), and of the corresponding CSF C₄ index were found in 16 and 7 patients, respectively, as evidence of intrathecal synthesis. Only minor differences of the frequencies of elevated CSF C₃ and C₄ indices were encountered over the course of AM up to 2 months after onset. The occurrence of intrathecal C₃ and C₄ synthesis in AM is proposed as reflecting activation of hitherto unknown significance within the central nervous system.     

Expression of the α1, α2 and α3 isoforms of the GABAA receptor in human alcoholic brain

The expression of the α₁, α₂ and α₃ isoforms of the GABA_A receptor was studied in the superior frontal and motor cortices of 10 control, 10 uncomplicated alcoholic and 7 cirrhotic alcoholic cases matched for age and post-mortem delay. The assay was based on competitive RT/PCR using a single set of primers specific to the α class of isoform mRNA species, and was normalized against a synthetic cRNA internal standard. The assay was shown to be quantitative for all three isoform mRNA species. Neither the patient's age nor the post-mortem interval significantly affected the expression of any isoform in either cortical area. The profile of expression was shown to be significantly different between the case groups, particularly because α₁ expression was raised in both groups of alcoholics cf controls. The two groups of alcoholics could be differentiated on the basis of regional variations in α₁ expression. In frontal cortex, α₁ mRNA expression was significantly increased when uncomplicated alcoholics were compared with control cases whereas alcoholic-cirrhotic cases were not significantly different from either controls or uncomplicated alcoholic cases. In the motor cortex, α₁ expression was elevated only when alcoholic-cirrhotic cases were compared with control cases. There was no significant difference between case groups or areas for any other isoform. © 1997 Elsevier Science B.V. All rights reserved.