Apelin对大鼠离体肺动脉环的舒张作用及与一氧化氮的关系

目的：探讨新的小分子活性肽Apelin对大鼠离体肺动脉环的舒张作用及与一氧化氮（NO）途径的关系,并比较低氧大鼠的肺动脉环对Apelin的舒张反应与正常大鼠的差异。方法：36只大鼠随机分为正常组与低氧组;采用离体血管环灌流法,检测Apelin对去甲肾上腺素（NE）预收缩的大鼠离体肺主动脉环的舒张效应,观察去内皮或用一氧化氮合酶抑制剂（L-NAME）、可溶性鸟苷酸环化酶（sGC）抑制剂（ODQ）孵育后该舒张率的变化。结果：①在正常组大鼠肺动脉环,Apelin（0.01~100 nmol/L）具有浓度依赖性的舒张效应。去除内皮后,Apelin对NE预先收缩的肺血管舒张效应明显减弱（P〈0.01）。L-NAME或ODQ预孵育后,Apelin的舒张效应均明显减弱（P均〈0.01）。②低氧组大鼠的肺动脉环对Apelin的舒张反应明显低于正常组大鼠,在最大浓度100 nmol/L时,Apelin的效应低60.45%（P〈0.01）,而两组EC50相比差异无显著性（P〉0.05）。结论：Apelin具有内皮依赖性的舒张肺动脉环的作用,该效应与NO-sGC-cGMP信号途径有关;低氧大鼠的离体肺动脉环对Apelin的舒张反应减弱。     

高脂高糖饮食对自发性高血压大鼠腹主动脉舒张功能及VCAM-1和ICAM-1mRNA表达的影响

目的:探讨高脂高糖饮食对自发性高血压大鼠(spontaneously hypertensive rats,SHR)腹主动脉血管舒张功能及血管间粘附分子-1 (vascular adhesion molecule-1,VCAM-1)和细胞间粘附分子-1(intercellular adhesion molecule-1,ICAM-1)mRNA表达的影响.方法:将24只6周龄雄性SHR大鼠随机分成高脂高糖饲料组(实验组,n=12)和普通饲料组(对照组,n=12).每3周测量其空腹体重,12周后处死大鼠,分别取两组动物的腹主动脉做离体血管环对乙酰胆碱(Acetylcholine,Ach)的舒张功能实验,并提取主动脉总RNA,通过实时定量RT-PCR实验检测其VCAM-1和ICAM-1 mRNA的表达.结果:从第6周开始,实验组SHR的体重较对照组明显增加(P＜0.01).12周时,实验组血管环对Ach的最大舒张率较对照组明显降低(69.20± 5.25 vs.79.10± 3.84,P＜0.01);实验组动脉VCAM-1 mRNA的相对表达量是对照组的1.97倍,差异有统计学意义(197.91±22.16 vs.100.33±11.44,P＜0.01),而两组ICAM-1mRNA表达的比较差异无统计学意义(97.75±8.05 vs.100.25±10.83,P＞0.05).结论:高脂高糖饮食能致SHR腹主动脉血管舒张功能明显降低,可能与其显著增加其主动脉VCAM-1 mRNA的表达有关.     

褪黑素改善内毒素血症大鼠血管反应性

观察褪黑素(melatonin,MT)对脂多糖(lipopolysaccharide,LPS)诱导的体循环和肺循环血管反应性失调的影响,并探讨可能的作用机制。实验分为溶剂对照组、LPS组、LPS+MT组和MT组。制备离体胸主动脉环和肺动脉环,应用血管张力检测技术检测各组血管环对苯肾上腺素(phenylephrine,PE)和乙酰胆碱(acetylcholine,ACh)的反应性并绘制累积剂量反应曲线;制备各组血管组织匀浆,测定丙二醛(malondialhyde,MDA)和超氧化物歧化酶(superoxidedismutes,SOD)含量变化。结果显示:与对照组相比,LPS6h后胸主动脉对PE的收缩反应减弱(P<0.01),对PE(1×10–8~1×10–5mol/L)累积剂量反应曲线下移;而肺动脉对ACh的舒张反应显著下降(P<0.01),对ACh(1×10–8~1×10–5mol/L)累积剂量反应曲线下移。加用MT可显著改善LPS诱导的胸主动脉对缩血管剂PE的低反应性,同时可逆转LPS对肺动脉舒张反应的抑制,LPS+MT组胸主动脉对PE的累积剂量反应曲线和肺动脉对ACh的累积剂量反应曲线位于对照组和LPS组之间;MT还可对抗LPS导致的脂质过氧化,使MDA含量减少,提高抗氧化酶SOD的活性。上述结果提示,MT可改善内毒素血症大鼠的血管反应性失调,抗氧化途径可能是其发挥保护作用的机制之一。     

葡萄籽中原花青素对实验动物主动脉收缩和血小板聚集的影响

目的:研究葡萄籽中原花青素(PA)对大鼠离体主动脉平滑肌收缩活动和兔血小板聚集的影响.方法:采用大鼠离体主动脉环灌流方法,记录主动脉环张力变化,观察PA对去甲肾上腺素(NA)和KCl预收缩大鼠离体主动脉平滑肌收缩反应的舒张作用以及对NA量效曲线的影响.比浊法测定兔血小板聚集.结果:PA能明显抑制NA(10-6mol/L)预收缩大鼠离体主动脉环的反应,使NA量效曲线压低,最大反应降低,此作用无内皮依赖性,但对KCl预收缩主动脉环的舒张作用无明显影响,也不影响花生四烯酸(AA),ADP和胶原(collagen)蛋白诱导的兔血小板聚集.结论:PA能对抗NA而不影响KCl诱导的大鼠离体主动脉平滑肌的收缩,不影响兔血小板聚集.     

外源性硫化氢对家兔内毒素休克诱发肺动脉高压的干预作用*

目的: 探讨外源性硫化氢(H₂S)对家兔内毒素休克(ES)诱发肺动脉血管反应性的影响。方法: 本实验采用家兔经颈静脉注射脂多糖(LPS,8 mg/0.8 ml/kg)复制家兔ES模型,并提前15 min腹腔注射H₂S供体硫氢化钠(NaHS,28 μmol/kg)进行干预。随机将新西兰大耳白家兔分为4组(n=8):溶剂对照组、LPS组、LPS+NaHS组和NaHS组。监测平均动脉压(MAP)和平均肺动脉压(MPAP)的变化;应用血管环张力测定技术,检测各组家兔离体肺动脉张力变化;应用光镜和扫描电镜分别观察肺动脉管壁结构及肺动脉内皮细胞超微结构变化。结果: ①注射LPS后家兔出现MAP降低、MPAP升高,成功复制家兔ES模型;与LPS组相比,LPS+NaHS组家兔MPAP在各个时间点均显著降低(P均﹤0.05);②与正常对照组相比,LPS组家兔肺动脉对苯肾上腺素(PE)的收缩反应增强,对乙酰胆碱(ACh)的舒张反应降低(P均﹤0.01);与LPS组相比,LPS+NaHS组家兔肺动脉对PE的收缩反应降低,而对ACh的舒张反应增强(P均﹤0.05)。③光镜下可见正常对照组家兔血管内皮细胞结构连续,内皮下弹力纤维完整,平滑肌层排列整齐;LPS组家兔部分肺动脉内皮细胞脱落,内皮下弹力纤维断裂,平滑肌层结构紊乱;与LPS组相比,LPS+NaHS组家兔肺动脉壁各层损伤减轻; NaHS组肺动脉壁各层形态结构接近正常对照组。扫描电镜检查发现LPS组家兔肺动脉部分内皮细胞缺失;LPS+NaHS组肺动脉内皮细胞形态接近对照组,仅可见细胞间隙稍增宽,未见细胞脱落。结论: 外源性H₂S可保护肺动脉内皮细胞,调节ES时肺动脉反应性的改变,从而降低ES家兔PAH。     

花生衣提取液对离体血管环和心脏活动的影响

研究花生衣提取液及其有效成分对离体血管环及心脏的影响。以大鼠离体胸主动脉血管环及蛙类离体心脏为研究对象,观察花生衣提取液及其有效成分对血管环张力、心脏心率和平均张力的影响,利用高效液相色谱法分析其有效成分。结果显示,花生衣提取液对血管环及KCl和NE所致的主动脉环收缩反应具有显著的舒张作用;可明显降低离体心脏心搏频率和平均张力。HPLC结果显示白藜芦醇是花生衣提取液有效成分之一,且与花生衣提取液的作用效果一致。实验结果表明花生衣提取液呈内皮依赖性舒张血管平滑肌,可明显降低离体心脏的心跳频率和收缩力,具有一定的舒张血管和保护心脏的效果,其有效成分是白黎芦醇。     

内源性硫化氢在脂多糖引起的肺动脉高压中的作用

为观察硫化氢(hydrogen sulfide,H2s)在脂多糖(1ipopolysaccharide,LPS)引起的肺动脉高压中的作用,应用离体血管环张力测定方法测定肺动脉反应性,采用生物化学方法测定肺动脉组织中H2S产出率和胱硫醚-γ-裂解酶(cystathionine γ-lyase,CSE)活性,定量PCR方法测定肺动脉组织中CSE表达水平.结果如下:(1)与对照组相比,LPS可显著升高肺动脉平均压(mean pulmonary arterial pressure,mPAP)[(1.82±0.29)kPa vs(1.43±0.26)kPa,P<0.01],降低肺动脉组织中H2S产出率[(26.33±7.84)vs(42.92±8.73)pmoFg wet tissue per minute,P<0.01]和ACh诱导的肺动脉内皮依赖性舒张反应[(75.72±7.22)%vs(86.40±4.40)%,P<0.01];(2)NariS可部分逆转上述变化,而PPG加剧上述变化;(3)CSE活性和CSE mRNA表达的变化与H2S产出率的变化相同.结果提示,LPS对内皮依赖性舒张反应的抑制导致肺动脉高压的发生,此作用可能与H2S有关.     

胰岛素对离体大鼠胸主动脉血管张力的影响

制备离体大鼠胸主动脉环,分有内皮组和去内皮组,采用离体血管灌流技术,观察胰岛素对去氧肾上腺素（PE）和氯化钾（KCl）预收缩的胸主动脉环收缩张力的影响。结果表明胰岛素对PE预收缩的胸主动脉环产生浓度依赖性的舒张作用,且有内皮组和去内皮组间无显著差异。胰岛素对KCl预收缩的胸主动脉环没有显著影响。胰岛素对PE预收缩的胸主动脉环有非内皮依赖性舒张作用。     

川芎嗪对慢性缺氧大鼠肺动脉和主动脉的离体舒张作用

用生物测定法观察了川芎嗪对慢性缺氧大鼠肺动脉和主动脉环的舒张效应,并与乙酰胆碱的舒血管作用进行了比较。结果表明:川芎嗪对慢性缺氧大鼠肺动脉和主动脉的舒张作用均与平原组无明显差异。慢性缺氧明显减低了乙酰胆碱诱发的肺动脉内皮依赖性舒张反应,但不影响川芎嗪对肺血管的舒张作用。提示川芎嗪对肺血管的舒张作用不依赖于内皮。川芎嗪对肺动脉的舒张作用明显大于体动脉。这些特性有利于川芎嗪对肺动脉高压的治疗。     

Gαq/11 和 PDGF依赖性信号转导通路在大鼠主动脉再狭窄中的作用

采用大鼠主动脉球囊内皮剥脱术制备主动脉狭窄模型,观察Gαq/11和PDGF信号转导通路在大鼠主动脉球囊损伤后狭窄时血管平滑肌细胞(VSMC)增殖和迁移中的作用.实验分假手术组、损伤1 d组和损伤14 d组,观察形态学变化,检测血管紧张素转换酶(ACE)活性和主动脉磷脂酶C(PLC)活性,用免疫印迹法测定主动脉血小板源生长因子(PDGF)受体β和Gαq/11蛋白含量.结果显示:损伤1 d,主动脉内皮完全剥脱,VSMC无明显增殖和迁移,内膜无增厚.与假手术组比较,ACE活性增加382.7%(P＜0.01),PDGF受体β表达和PLC活性无明显变化,Gαq/11蛋白含量下降20.0%(P＜0.05).损伤14 d组,主动脉局部有新生内皮出现,中层VSMC大量增殖并向内膜下迁移,内膜显著增厚.ACE活性、PDGF受体β表达和PLC活性分别较假手术组升高420.2%(P＜0.01)、85.0%(P＜0.05)和186.2%(P＜0.05),Gαq/11蛋白表达下降33.1%(P＜0.01).结果提示,PDGF介导的信号转导通路可能是再狭窄时VSMC增殖的重要信号转导机制.     

Mitochondrial nitric oxide metabolism in rat muscle during endotoxemia

In this study, heart and diaphragm mitochondria produced 0.69 and 0.77 nmol nitric oxide (NO)/min mg protein, rates that account for 67 and 24% of maximal cellular NO production, respectively. Endotoxemia and septic shock occur with an exacerbated inflammatory response that damages tissue mitochondria. Skeletal muscle seems to be one of the main target organs in septic shock, showing an increased NO production and early oxidative stress. The kinetic properties of mitochondrial nitric oxide synthase (mtNOS) of heart and diaphragm were determined. For diaphragm, the KM values for O2 and L-Arg were 4.6 and 37 microM and for heart were 3.3 and 36 microM. The optimal pH for mtNOS activity was 6.5 for diaphragm and 7.0 for heart. A marked increase in mtNOS activity was observed in endotoxemic rats, 90% in diaphragm and 30% in heart. Diaphragm and heart mitochondrial O2*- and H2O2 production were 2- to 3-fold increased during endotoxemia and Mn-SOD activity showed a 2-fold increase in treated animals, whereas catalase activity was unchanged. One of the current hypotheses for the molecular mechanisms underlying the complex condition of septic shock is that the enhanced NO production by mtNOS leads to excessive peroxynitrite production and protein nitration in the mitochondrial matrix, causing mitochondrial dysfunction and contractile failure.     

Time-dependent expression of renal vaso-regulatory molecules in LPS-induced endotoxemia in rat

To elucidate roles of microvascular factors in the pathogenesis of renal complications during endotoxemia, that is characterized by renal vasoconstriction and systemic hypotension/generalized non-renal vasodilation, we profile the expression pattern and time-course of three key vaso-regulators, namely endothelin (ET)-1, nitric oxide (NO), and angiotensin II (Ang II). We hypothesize that disruption of the overall balance between vasodilatation and vasoconstriction in the kidney, during the early phase of sepsis, contribute to its (kidney) predisposition to acute renal failure. Adult male Wistar rats were rendered endotoxemic at different time points (1, 3, 6 and 10 h) by a single i.p. injection of lipopolysaccharide (LPS) (15 mg/kg) dissolved in saline. Control group was injected vehicle only (saline). Both systolic and diastolic blood pressures significantly decreased at different time points after LPS administration. Surprisingly, renal histopathological evaluation showed no remarkable changes in LPS-induced endotoxemia. However, overall, levels of the vaso-regulators and, where applicable, their respective receptors were upregulated: (1) plasma ET-1 increased 25-fold and peaked, as renal ET-1 mRNA, at 3 h; renal ET-1 protein and its receptors, ET type A (ET(A)) receptor (vasoconstrictive) and ET type B (ET(B)) receptor (vasodilatatory) increased in a time-dependent fashion, (2) Ang II increased by 53% compared to control, peaking at 6 h. However, while levels of Ang II type 1 (AT1) receptor increased over time after LPS injection, those of Ang II type 2 (AT2) receptor were downregulated, (3) data of NO system (NO-NOS), the key vasodilator, were the most intriguing. Whereas levels of renal NO increased time-dependently following LPS administration, with a 2240-fold increase in renal iNOS expression, levels of eNOS, were almost unchanged. In conclusion, the present study overall reveals intriguing and complex dynamics between levels of vasoconstrictors and vasodilators during the early phase of LPS-induced endotoxemia. These shifts in molecular expressions are likely triggered by compensatory mechanisms aimed at counteracting the undesirable and dominant effects of one group of vaso-regulatory moiety over the other.     

Endogenous peroxynitrite mediates mitochondrial dysfunction in rat diaphragm during endotoxemia.

It has been shown that nitric oxide (NO), synthesized by the inducible NO synthase (iNOS) expressed in the diaphragm during endotoxemia, participates in the development of muscular contractile failure. The aim of the present study was to investigate whether this deleterious action of NO was related to its effects on cellular oxidative pathways. Rats were inoculated with E. coli lipopolysaccharide (LPS) or sterile saline solution (controls) and studied at 3 and 6 h after inoculation. iNOS protein and activity could be detected in the rat diaphragm as early as 3 h after LPS, with a sustained steady-state concentration of 0.5 microM NO in the muscle associated with increased detection of hydrogen peroxide (H(2)O(2)). In vitro, the same NO concentration produced a marked increase in H(2)O(2) production by isolated control diaphragm mitochondria, thus reflecting a higher intramitochondrial concentration of nondiffusible superoxide anion (O(2)(-.)). In a similar way, whole diaphragmatic muscle and diaphragm mitochondria from endotoxemic rats showed a progressive increase in H(2)O(2) production associated with uncoupling and decreased phosphorylating capacity. Simultaneous with the maximal impairment in respiration (6 h after LPS), nitration of mitochondrial proteins (a peroxynitrite footprint) was detected and diaphragmatic force was reduced. Functional mitochondrial abnormalities, nitration of mitochondrial proteins, and the decrease in force were significantly attenuated by administration of the NOS inhibitor L-NMMA. These results show that increased and sustained NO levels lead to a consecutive formation of O(2)(-.) that reacts with NO to form peroxynitrite, which in turn impairs mitochondrial function, which probably contributes to the impairment of muscle contractility. during endotoxemia.     

Impact of leukocytes and platelets in mediating hepatocyte apoptosis in a rat model of systemic endotoxemia

Apoptotic hepatocytes have been demonstrated to represent an important signal for transmigration of leukocytes sequestered in sinusoids during endotoxemia in vivo. Beside leukocytes, platelets and their adhesion to endothelial cells and leukocytes have been implicated in inflammatory liver injury. Using in vivo multifluorescence microscopy, we examined the possibility that hepatocellular apoptosis causes both leukocytes and platelets to colocalize within the sinusoidal microvasculature of endotoxemic livers. We further addressed the issue whether cellular colocalization with apoptotic hepatocytes is cause or consequence of apoptosis. Intraperitoneal exposure of rats with LPS (5 mg/kg) induced liver injury after 6 and 16 h, as given by nutritive perfusion failure (20 +/- 2 and 21 +/- 2%), intrahepatic leukocyte (60 +/- 10 and 121 +/- 48 cells/mm(2)), and platelet (12 +/- 4 and 34 +/- 4 cells/mm(2)) accumulation as well as parenchymal cell apoptosis (4 +/- 1 and 11 +/- 2 cells/mm(2)) and caspase cleavage (4.7 +/- 2.4- and 7.0 +/- 3.0-fold increase; P < 0.05 vs. saline-exposed controls). Higher doses of LPS (10 mg/kg ip) further increased intrahepatic leukocyte and platelet accumulation but not the extent of parenchymal apoptosis. Detailed spatial analysis revealed colocalization of leukocytes (range 12-24%) but barely of platelets (<6%) with apoptotic hepatocytes in all endotoxemic groups studied. It is of interest, however, that platelets were found at increasing rates in colocalization with leukocytes at 6 and 16 h after LPS exposure (5 mg/kg LPS: 7 +/- 3 and 25 +/- 6%; 10 mg/kg LPS: 11 +/- 4 and 14 +/- 1%). Platelet-leukocyte events significantly correlated with the extent of caspase cleavage as an indicator of tissue apoptosis (P < 0.05; r = 0.82). Blockade of apoptosis by a pan-caspase inhibitor caused a significant reduction of leukocyte adherence and platelet-leukocyte colocalization on LPS exposure. On the other hand, leukocytopenic animals revealed reduced hepatocyte apoptosis, although values still exceeded those of controls, and in leuko- and thrombocytopenic animals, hepatocyte apoptosis was found reduced to control values. Taken together, LPS-associated hepatocyte apoptosis seems to be initiated by circulating blood cells that become adherent within the liver but might also contribute to further sustain the inflammatory cell-cell response.     

华支睾吸虫感染对大鼠肠道菌群移位和内毒素血症的影响

目的研究肠道细菌移位在华支睾吸虫病致病机制中的作用。方法建立华支睾吸虫感染大鼠模型。分别在造模后48 h(后尾蚴期)、18 d(童虫期)和35 d(成虫期),取肝、肺、淋巴结和血液组织,采用平板培养法进行细菌移位的检测;采用鲎三肽基质染色定量法检测血浆内毒素含量。结果感染18 d后,实验组肠道细菌移位率开始增高,至感染35 d时,细菌移位率为70%,明显高于对照组的10%,差异有统计学意义(P=0.0230.05);感染鼠以童虫期、成虫期细菌移位现象明显,总移位率为65%,与对照组10%比较,差异有统计学意义(u=3.59,P0.01),且在肝、肺、淋巴结和血液组织中,移位发生率分别为60%、15%、25%和10%,以肝脏部位最高;造模后18 d血浆内毒素水平明显增高,造模后35 d血浆LPS水平略有下降,但仍明显高于对照组,差异有统计学意义(t=7.612,P0.01)。结论华支睾吸虫感染可引发宿主肠道菌群移位,以肝组织多发,从而参与致病机制。     

Experimental endotoxemia induces leukocyte adherence and plasma extravasation within the rat pial microcirculation

Disturbance of capillary perfusions due to leukocyte adhesion, disseminated intravascular coagulation, tissue edema is critical components in the pathophysiology of sepsis. Alterations in brain microcirculation during sepsis are not clearly understood. The aim of this study is to gain an improved understanding of alterations through direct visualization of brain microcirculations in an experimental endotoxemia using intravital microscopy (IVM). Endotoxemia was induced in Lewis rats with Lipopolysaccharide (LPS, 15 mg/kg i.v.). The dura mater was removed via a cranial window to expose the pial vessels on the brain surface. Using fluorescence dyes, plasma extravasation of pial venous vessels and leukocyte-endothelial interaction were visualized by intravital microscopy 4 h after LPS administration. Plasma cytokine levels of IL1-beta, IL-6, IFN-gamma, TNF-alpha and KC/GRO were evaluated after IVM. A significant plasma extravasation of the pial venous vessels was found in endotoxemia rats compared to control animals. In addition, a significantly increased number of leukocytes adherent to the pial venous endothelium was observed in septic animals. Endotoxemia also induced a significant elevation of plasma cytokine levels of IL1-beta, IL-6, IFN-gamma, TNF-alpha and KC/GRO. Endotoxemia increased permeability in the brain pial vessels accompanied by an increase of leukocyte-endothelium interactions and an increase of inflammatory cytokines in the plasma.     

Down-regulation of prostaglandin F2 alpha receptors in rat liver during chronic endotoxemia.

Prostaglandin (PG) F2 alpha binding parameters were measured in purified plasma membrane preparations isolated from livers of chronically endotoxin-(ET) treated rats and corresponding controls. Two classes of binding sites were detected in both groups: high affinity, low capacity, with a KD of 44.4 +/- 8.8 nM for saline- and 28.6 +/- 11.3 nM for ET-treated rats (n = 5 for both, p greater than 0.05) and low affinity, high capacity with a KD of 1.12 +/- 0.49 microM for saline- and 1.24 +/- 0.43 microM for ET-treated rats (p greater than 0.05). Bmax values for high affinity sites were 1.01 +/- 0.18 fmol.mg-1 protein for saline- and 1.02 +/- 0.54 (same units) for ET-treated rats (p greater than 0.05). There was a significant difference (p less than 0.01) between the Bmax values for low affinity sites in saline- (675 +/- 332 fmol.mg-1 protein) and ET-treated rats (12 +/- 1, same units). This decrease in the amount of PGF2 alpha low affinity high capacity binding sites may underlie the depression of the PGF2 alpha stimulatory effect on hepatic gluconeogenesis induced by non-lethal, chronic ET treatment of rats, recently described by us (9).     

Thrombin and leukocyte recruitment in endotoxemia

Because thrombin has been implicated in sepsis, it has been proposed that antithrombin III (AT III) is beneficial due to its anticoagulatory and antiadhesive effects. Using intravital microscopy, we visualized leukocyte-endothelium interactions in postcapillary venules of the feline mesentery exposed to lipopolysaccharide (LPS). At a concentration of AT III that blocks leukocyte adhesion in postischemic mesentery, we found no role for thrombin in LPS-induced rolling, adhesion and emigration, or microvascular dysfunction. Furthermore, AT III did not attenuate leukocyte-endothelial interactions after tumor necrosis factor-alpha superfusion of the mesentery. In contrast, fucoidan, a selectin inhibitor, prevented almost all LPS-induced rolling and reduced adhesion, emigration, and microvascular dysfunction. In a model of endotoxemia, leukocyte recruitment into mesentery or lungs was unaffected by AT III. Finally, in a human cell system that mimics the flow conditions in vivo, human neutrophils rolled, adhered, and emigrated similar to the feline postcapillary microvessels, and AT III had no effect on leukocyte recruitment induced by LPS. If AT III has beneficial effects in endotoxemia, it is not due to a direct effect upon leukocyte rolling, adhesion, or emigration in postcapillary venules in vivo.     

Calcium overload in endotoxemia

E.coli endotoxin stimulates endogenous lipolysis in the $\text{in vitro}$ perfused rat heart. Verapamil^® inhibits endotoxin- (as well as glucagon-) stimulated lipolysis. This suggests that the endotoxin used increases the availability of Ca⁺⁺ to the lipolytic system in the cardiocytes. This conclusion is supported by the observed stimulation of contractility of the heart, especially during perfusion at a low Ca⁺⁺ concentration.The endotoxin was found to inhibit ATP-dependent Ca⁺⁺ accumulation in sarcolemma vesicles prepared from rat heart. A direct Ca⁺⁺ ionophoric action of the endotoxin on these vesicles could be excluded.It is discussed that Ca⁺⁺ overload may not be confined to the cardiovascular system during endotoxemia.