蛙心灌流实验中心肌收缩力不稳定的原因分析与对策

1866年蛙心灌流技术的建立开创了离体器官灌流的新纪元,目前蛙心灌流依然是医学和生物学专业学生培养中的重要实验。简要回顾蛙心灌流技术的历史及利用蛙心灌流实验曾经取得的成就,结合当前实验教学的实际问题,从生理学角度分析蛙心灌流过程中心肌收缩力不稳定的根源,并采取一些简单有效的措施进行改进,使蛙心灌流实验中心肌收缩力的稳定性和精确性大幅提高。     

各种离体蛙心磁化灌流液的效果观察

在任氏液中分别加入家兔脱纤血清和计定浓度的Na、K、Ca、Ad、Ach磁化溶液,配制成血清灌流液和磁化灌流液。用这两种灌流液和任氏液进行离体蛙心灌流实验,在二道生理记录仪上描记蛙心搏动曲线。可观察到血清灌流液能加强心脏功能,磁化灌流液有显著的效果。     

各种离体蛙心 磁化灌流液的效果观察

在任氏液中分别加入家兔脱纤血清和计定浓度的Na、K、Ca、Ad、Ach磁化溶液,配制成血清灌流液和磁化灌流液。用这两种灌流液和任氏液进行离体蛙心灌流实验,在二道生理记录仪上描记蛙心搏动曲线。可观察到血清灌流液能加强心脏功能,磁化灌流液有显著的效果。     

用于核磁共振检测的离体心脏灌流模型

本报告是关于核磁共振研究生理学问题的灌流模型。我们解决了Ｌａｎｇｅｎｄｏｒｆｆ灌流装置用于核磁共振研究时存在的问题,如远距离灌流、保温、保氧和灌流液回收等,建立了稳定的可供核磁共振测量用的灌流模型。在这个装置中离体大鼠心脏的节律性活动可维持９０ｍｉｎ以上。     

钙离子对心脏的反常作用

“钙离子反常作用”是在离体灌流的动物心脏先用无钙灌流液(除Ca~(2+)缺乏外其它成分均正常)灌流一定时间,继而恢复正常灌流时所观察到的一种严重心肌损害现象。该现象的发生可能是由于恢复正常灌流时Ca~(2+)的大量快速内流造成细胞Ca~(2+)过荷所致;而无钙灌流则使细胞膜超微结构和通透性发生变化,对Ca~(2+)通透性显著增高。     

单片机控制的颈动脉窦区自动灌流系统的研究

目的：建立一种自动控制颈动脉窦区灌流压的新方法。方法：采用AT89C2051单片计算机构成谦价实用的灌流控制器,钭它与LDB-M型电子蠕动泵、实验动物的颈动脉窦区构成自动灌流系统。结果及结论：该系统能对大鼠颈动脉窦区进行均匀斜坡升压,阶梯升压-降压灌流,并已用于压力感受器反射效应研究中,此系统能保证灌流曲线的准确性和可重复性。进一步提高了实验的技术水平。     

简单的恒温恒壓灌流器

在溫血動物肢體和器官灌流的實驗中,均要求灌流液的溫度和壓力維持恒定,而通常實驗室中所用的吊桶式灌流器,很難滿足這項要求。有些成品的恒溫恒壓灌流儀器,結構較為複雜,價昂而購置不易。今為研究的需要,設計一個灌流器,可以調節溫度與壓力,且可使其維     

脑缺血／再灌流脑微血管内皮细胞ELAM—1和ICAM—1mRNA表达的研究

目的：探讨ELAM-1和ICAM-1在局部脑缺血/再灌流炎性反应过程中的作用。方法：采用厅局级龙线栓堵大脑中动脉造成局部脑缺血/再灌流模型,用RT-PCR方法检测缺血侧脑组织缺血/再灌流不同时间点ELAM-1和ICAM-1mRNA的表达。结果：假手术组脑组织未见ELAM-1和ICAM-1mRNA的表达,手术组非缺血侧脑组织仅见少量表达。脑缺血/再灌流后1h,缺血侧脑组织ELAM-1和ICAM-1mRNA的表达量已开始升高;再灌流后3h,ICAM-1mRNA的上调达高峰,而ELAM-1mRNA的上调在缺血/再灌流后6h达高峰,且持续至缺血/再灌流后48h。结论：EL-AM-1和ICAM-1参与了局部缺血再灌流脑组织损伤的病理过程。二者在白细胞进入缺血区脑组织的病理过程中发挥着重要作用。     

哺乳动物细胞灌流培养工艺开发与优化

近年来生物药市场需求量激增,高产量、高质量、低成本的哺乳动物细胞灌流培养工艺顺势成为工业界和学术界普遍关注的热点。文中围绕灌流培养工艺特有的操作环节及工艺优化应着重关注的细节展开论述,综述了近年来在灌流培养工艺开发和优化上取得的进步和提出的策略,以期为哺乳动物细胞灌流培养技术的开发提供参考。     

颈动脉窦内压的变化速率对反射性降压效应的影响

在成年狗身上制备右侧孤离颈动脉窦,借助灌流装置用饱和氧的任氏液对其进行灌流。灌流压为搏动性的。通过改变每搏泵出量、灌流管道的阻力和弹性来调节灌流压及其变化速率。用多导生理记录仪同步记录股动脉血压、窦内灌流压及其变化速率。本文主要观察窦内压的变化速率对降压反射的影响。在8只狗身上共进行了93次实验。结果表明,在窦内压相同的情况下,灌流压的上升速率愈快,降压效应愈明显,而其下降速率则无显著作用。已有资料证明搏动性窦内压所引起的降压效应较非搏动性压力更为明显。由此可见,狗的颈动脉窦压力感受器不仅对搏动性压力而且对其上升的变化速率也很敏感。     

一氧化氮对谷氨酸诱发的大鼠海马脑片CA1区神经元活动的抑制

用细胞外记录单位放电技术,在大鼠海马脑片上观察了Ｌ－精氨酸（Ｌ－ａｒｇ）、Ｎ－硝基Ｌ－精氨酸（Ｌ－ＮＮＡ）及ＳＩＮ－１对谷氨酸（ｇｌｕｔａｍａｔｅ,Ｇｌｕ）诱导的ＣＡ１区神经元放电的影响。旨在了解Ｌ－精氨酸：ＮＯ通路在谷氨酸诱发的海马放电中的作用及其可能的机制。结果如下：（１）用ＧｌＵ（０．５ｍｍｏｌ／Ｌ）灌流海马脑片１ｍｉｎ,１２个放电单位放电频率明显增加,表现为癫痫样放电;（２）海马脑片２ｍｉ     

Effect of L-arginine on the relaxation caused by sodium nitroprusside on isolated rat renal artery

In the present study we investigated the mechanism of nitric oxide induced relaxation of renal arteries, with or without endothelium, taken from normotensive and spontaneously hypertensive (SH) rats. With this purpose in mind, the effects of the nitric oxide donor, sodium nitroprusside (SNP), with and without L-arg in the medium, on isolated rat renal artery relaxation were studied. Relaxing effect of SNP was higher in normotensive (10(-5) M of SNP caused 220% of relaxation in the cases with endothelium and 240% without endothelium), in comparison with SH rats (100% of relaxation with endothelium and 150% without). L-arg antagonized the relaxing effect of SNP in the examined renal arteries, more in normotensive (100-160% with endothelium and 110-195% without) than in hypertensive ones (0-10% with endothelium and 35-75% without) at SNP concentrations 10(-7) - 10(-5) M, respectively (*P < 0.05; **P < 0.001). L-arg did not significantly change relaxing effect of SNP in the isolated renal arteries with endothelium taken from SH rats, which show that L-arg, by modifying the chemical versatility of NO into redox active forms -nitrosonium (NO+) and -nitroxyl (NO-), produces different relaxing effects in normotensive and hypertensive isolated arteries of rats, with or without endothelium, potentiating the role of nitroxyl induced relaxation in SH rats.     

内皮素对麻醉大鼠颈动脉窦压力感受器活动的影响

在麻醉大鼠隔离灌流颈动脉窦区条件下记录窦神经传入放电,观察内皮素（ＥＴ－１）对动脉压力感受器活动的影响。结果如下：（１）在颈动脉窦区灌流１ｎｍｏｌ／Ｌ ＥＴ－１时,压力感受器机能曲线向左上方移位,曲线的最大斜率（ＰＳ）增加,窦神经传入放电最大积分值（ＰＩＶ）增大。由此提示,这一剂量的ＥＴ－１对压力感受器活动有易化作用。（２）用１０ｎｍｏｌ／Ｌ ＥＴ－１灌流时,压力感受器机能曲线则向右下方移位,ＰＳ     

Modulation of baroreceptor activity by gene transfer of nitric oxide synthase to carotid sinus adventitia

Administration of nitric oxide (NO) or NO donors to isolated carotid sinus and carotid bodies inhibits the activity of baroreceptor and chemoreceptor afferent nerves. Furthermore, NO synthase (NOS) is present in endothelial cells and in sensory nerves innervating the carotid sinus region. The major goal of this study was to determine whether overexpression of NOS in carotid sinus modulates baroreceptor activity. Rabbits were anesthetized, and adenoviral vectors (5 x 10(8) plaque-forming units) encoding genes for either beta-galactosidase (beta-Gal) or endothelial type III NOS (eNOS) were applied topically to the adventitial surface of one carotid sinus. In some experiments, the NOS inhibitor N(G)-nitro-l-arginine methyl ester (l-NAME) was applied to the carotid sinus immediately after the vector. Four to five days later, baroreceptor activity and carotid sinus diameter were measured from the vascularly isolated carotid sinus of the anesthetized rabbits. Transgene expression was confirmed by X-Gal staining of beta-Gal and measurement of NOS activity by citrulline assay. The expression was restricted to the carotid sinus adventitia. Baroreceptor activity was decreased significantly, and the pressure-activity curve was shifted to higher pressures in eNOS-transduced (n = 5) compared with beta-Gal-transduced (n = 5) carotid sinuses. The pressure corresponding to 50% of maximum activity averaged 55 +/- 6 and 76 +/- 7 mmHg in beta-Gal- and eNOS-transduced carotid sinuses, respectively (P < 0.05). Decreased baroreceptor activity was accompanied by a significant increase in carotid diameter in the eNOS-transduced carotid sinuses (n = 5). l-NAME prevented the inhibition of baroreceptor activity and the increase in carotid diameter in eNOS-transduced carotid sinuses (n = 5). We conclude that adenoviral-mediated gene transfer of eNOS to carotid sinus adventitia causes sustained, NO-dependent inhibition of baroreceptor activity and resetting of the baroreceptor function curve to higher pressures.     

八肽胆囊收缩素对大鼠颈动脉窦压力感受器反射的抑制作用

在36只隔离灌流颈动脉窦区的麻醉大鼠上,观察了八肽胆囊收缩素(cholecystokinin octapepide,CCK-8)对颈动脉窦压力感受器反射的影响。其结果如下：(1)以CCK-8(0．1、0．5、1．0μmol／L)隔离灌流颈动脉窦区时,压力感受器机能曲线向右上方移位,曲线最大斜率(peak slope,PS)减小,反射性血压下降幅度(reflex decrease,RD)减少,阈压(threshold pressure,TP)和饱和压(saturation pressure,SP)均增高。其中RD、PS和TP呈明显的剂量依赖性;(2)用CCK-8的非特异性受体拮抗剂丙谷胺(100μmol／L)预处理后,能明显减弱CCK-8(0．50mol/L)对压力感受器反射的抑制;(3)预先灌流一氧化氮合酶(nitric oxide synthase,NOS)阻断剂(L-NAME,100μmol／L),不能阻断CCK-8(0．5μmol/L)对压力感受器反射的影响;(4)用Ca^2 通道激动剂Bay K 8644(500nmol／L)预处理后,也能明显减弱CCK-8(0．5μmol／L)对压力感受器反射的抑制作用。以上结果提示,CCK-8是通过作用于颈动脉窦压力感受器神经元末梢上的受体而起到抑制作用的,其机制可能为抑制了牵张敏感性通道,致使Ca^2 离子内流减少,而与内皮细胞释放NO无关。     

Vascular and renal effects of dopamine during extracellular volume expansion: Role of nitric oxide pathway

OBJECTIVE: The aim of the study was to determine the possible role of NO-system activation in vascular and renal effects of the dopaminergic system and the probable interaction between both systems during acute volume expansion in rats. DESIGN AND METHODS: Expanded (10% bw) and non-expanded anaesthetized male Wistar rats were treated with haloperidol, a DA receptor antagonist (3 mg/kg bw, ip). Mean arterial pressure, diuresis, natriuresis, renal plasma flow, glomerular filtration rate, nitrites and nitrates excretion (NOx) were determined. NADPH diaphorase activity was measured using a histochemistry technique in kidney, aorta and renal arteries. NOS activity in kidney and aorta from expanded and non-expanded animals was determined with L-[U14C]-arginine substrate, in basal conditions and after DA (1 microM) administration. RESULTS: The hypotensive effect of L-arg and hypertension induced by L-NAME were not modified by haloperidol. This blocker reverted the increase in diuresis, natriuresis and RPF induced by L-arg in both groups. Dopaminergic blockade induced a decrease in NOx excretion and in NADPH-diaphorase activity in glomeruli, proximal tubule and medullar collecting duct and in endothelium and vascular smooth muscle of renal arteries. DA induced an increase in NOS activity in renal medulla and cortex in both groups, but no changes in the aorta were observed. CONCLUSIONS: Our results suggest that renal DA would be associated with the renal response induced by NO during extracellular volume expansion. NO-system activation would be one of the mechanisms involved in renal DA activity during saline load, but NO appears not to be involved in DA vascular effects.     

胍丁胺抑制大鼠颈动脉窦压力感受器活动

在麻醉大鼠隔离灌流颈动脉窦区条件下,记录窦神经传入放电,观察胍丁胺（agmatine,Agm)对动脉压力感受器活动的影响,结果如下：（1）以1mmol/L Agm隔离灌流大鼠颈动脉窦区时,窦内压－窦神经传入放电积分（ISP－ISNA）关系曲线向右下方移位,曲线的最大斜率（PS）降低,窦神经传入放电量最大积分值（PIV）减小,再分别以5,10mmol/L Agm灌流时,机能曲线向右下方移位更为明显,PS及PIV降低更加明显,从而表明Agm抑制压力感受器活动且呈剂量依赖性,（2）α2－肾上腺素受体（α2－adrenoceptor,α-AR）和咪唑啉受体（IR）的阻断剂咪唑克生（0．1mmol/L)可阻断Agm的上述效应。（3）预先灌流α-AR能亨宾（15umol/L)可部分阻断Agm的抑制效应。（4）预先灌流Ca^2 通道激动剂Bay K8644(500mmol/L)亦可取消Agm对窦神经传入放电的影响,以上结果表明,Agm对基动脉窦压力感受器活动有抑制作用,此作用由IR和α-AR介导,并与颈动脉窦压力感受器活动时Ca^2 内流减少有关。     

NO前体和供体对大鼠海马脑片神经元活动的影响

应用细胞记录单位放电技术,在大鼠海马脑片上观察了左旋精氨酸,Ｎ－硝在左旋精氨酸,ＳＩＮ－１,及亚甲基蓝对ＣＡ１区神经元自发放电的影响,旨在了解左旋精氨酸;ＮＯ通路在海马放电中的作用及其可能的机制。实验结果如下：１．用Ｌ－ａｒｇ（１ｍｍｏｌ／Ｌ）灌流海马脑片２ｍｉｎ,在５４个放电单位中有４２个单位放电频率降低,１２个单位无明显反应。     

Nitric oxide infused in the solitary tract nucleus blocks brain glucose retention induced by carotid chemoreceptor stimulation

Previous work has shown that the carotid body glomus cells can function as glucose sensors. The activation of these chemoreceptors, and of its afferent nucleus in the brainstem (solitary tract nucleus - STn), induces rapid changes in blood glucose levels and brain glucose retention. Nitric oxide (NO) in STn has been suggested to play a key role in the processing of baroreceptor signaling initiated in the carotid sinus. However, the relationship between changes in NO in STn and carotid body induced glycemic changes has not been studied. Here we investigated in anesthetized rats how changes in brain glucose retention, induced by the local stimulation of carotid body chemoreceptors with sodium cyanide (NaCN), were affected by modulation of NO levels in STn. We found that NO donor sodium nitroprusside (SNP) micro-injected into STn completely blocked the brain glucose retention reflex induced by NaCN chemoreceptor stimulation. In contrast, NOS inhibitor N(ω)-nitro-L-arginine methyl ester (L-NAME) increased brain glucose retention reflex compared to controls or to SNP rats. Interestingly, carotid body stimulation doubled the expression of nNOS in STn, but had no effect in iNOS. NO in STn could function to terminate brain glucose retention induced by carotid body stimulation. The work indicates that NO and STn play key roles in the regulation of brain glucose retention.     

L—arg斤LNNA对大鼠胸主动脉内皮损伤后舒缩反应及cGMP…

本研究在大鼠胸主动脉内皮损伤内膜增生模型上观察了Ｌ－ａｒｇ和ＬＮＮＡ对大鼠胸主动脉条的血管反应性及ｃＧＭＰ含量的影响。血管反应性观察及血管局部ｃＧＭＰ测定发现,大鼠胸主动脉内皮损伤后３天对－ａｒｇ及ＬＮＮＡ的舒缩反应明显受损,血管局部基础ｃＧＭＰ明显下降,用Ｌ－ａｒｇ和ＬＮＮＡ干预后的ｃＧＭＰ变化亦明显受损,损伤后１０天以上现象明显恢复,损伤后２１天进一步恢复,但仍不能恢复正常。结果表明,内皮损伤