The effects of adrenaline and noradrenaline on venous return and regional blood flows in the anaesthetized cat with special reference to intestinal blood flow

1. In cats, a venous long-circuit technique was used to measure the blood flows in the superior vena cava and the hepatic, renal and iliac segments of the inferior vena cava. The sum of these flows gave the venous return (minus coronary and bronchial flows). In further experiments using an electromagnetic flowmeter, flow in the portal vein and in the superior mesenteric and coeliac arteries was measured.2. Approximately two-thirds of the hepatic blood flow is derived from the portal vein.3. After block of conduction in the cervical region of the spinal cord, the proportions of the venous return coming from each region during the control periods were not significantly altered although the arterial pressure and total venous return were decreased.4. Intravenous infusions of adrenaline caused an increase in venous return which was associated with a marked increase in hepatic blood flow. The increase in hepatic blood flow was due to an increase in flow in the superior mesenteric artery and portal vein. Flow in the coeliac artery remained unchanged. This response was unaffected by block of the cervical region of the spinal cord and by atropine or pentolinium.5. Intravenous infusions of noradrenaline caused little change in venous return or regional blood flows. Small increases in superior mesenteric artery flow were occasionally seen and on cessation of the infusion a large but brief increase occurred. These facts suggest that noradrenaline has a similar action to adrenaline but this is masked by concomitant vasoconstriction.     

Mechanisms underlying pre- and postjunctional effects of neuropeptide Y in sympathetic vascular control

The effects of porcine neuropeptide Y (NPY) regarding sympathetic vascular control were studied in vitro on isolated rat blood vessels. The 10(-9)M NPY enhanced (about two-fold) the contractile responses to transmural nerve stimulation (TNS), noradrenaline (NA) and adrenaline (about two-fold) in the femoral artery. Higher concentrations of NPY (greater than 10(-8)M) caused an adrenoceptor-resistant contraction per se. The TNS-evoked [3H]NA efflux was significantly reduced by NPY in a concentration-dependent manner (threshold 10(-9)M). The calcium antagonist, nifedipine, abolished the contractile effects of NPY and the NPY-induced enhancement of NA contractions but did not influence the prejunctional inhibition of [3H]NA release. Receptor-binding studies showed that the ratio of alpha 1-to alpha 2-adrenoceptors in the femoral artery was 30:1. The NPY did not cause any detectable change in the number of alpha 1-or alpha 2-adrenoceptor binding sites or in the affinity of alpha 2-binding sites, as revealed by prazosin- and clonidine-binding, respectively. The NPY also inhibited the TNS-evoked [3H]NA release (by 42-86%) in the superior mesenteric and basilar arteries and in femoral and portal veins. The NPY still depressed TNS-evoked [3H]NA secretion from the portal vein in the presence of phentolamine. The NPY caused a clear-cut contraction in the basilar artery, increased the contractile force of spontaneous contractions in the portal vein, while only weak responses were observed in the superior mesenteric artery and femoral vein. The NA-induced contraction was markedly enhanced by NPY in the superior mesenteric artery, only slightly enhanced in the portal vein and uninfluenced in the femoral vein. In conclusion, in all blood vessels tested, NPY depresses the TNS-evoked [3H]NA secretion via a nifedipine-resistant action. Furthermore, NPY exerts a variable, Ca2+-dependent vasoconstrictor effect and enhancement of NA and TNS contractions.     

一种新的大鼠门静脉动脉化模型

背景：目前文献报道的大鼠门静脉动脉化模型有缝合法或支架法,2种方法在血管通畅率及操作便利性上均不太理想。 目的：建立稳定的操作简便的大鼠门静脉动脉化动物模型。 方法：采用同种异体血管套入式缝合及袖套法建立大鼠门静脉动脉化模型40例。切除左肾,将左肾动脉与门静脉残端通过同种异体血管连接,左肾静脉借助袖套与肠系膜上静脉连接。另取10只大鼠作为假手术组。术后观察大鼠的体质量变化和存活情况,2周行磁共振血管成像,1个月检测大鼠肝功能,2个月处死大鼠探查门静脉血流通畅情况并观察肝脏的病理学改变。 结果与结论：造模过程中有1只大鼠死亡,其余39只均存活至术后2个月,造模成功率为98%(39/40)。术后1个月,模型组与假手术组大鼠体质量,血清白蛋白、谷丙转氨酶、碱性磷酸酶和胆碱酯酶差异均无显著性意义(P > 0.05)。术后2个月,模型组门静脉通畅率为95%(37/39)。磁共振血管成像及病理结果均未见明显异常。提示,利用同种异体血管套入式缝合及袖套法建立的大鼠门静脉动脉化模型操作简便、省时、成功率高,是一种可行、稳定、可靠、可重复性强的方法。     

Effect of substance P on various vascular beds in the dog.

Using the electromagnetic flowmeter technique, the blood flow in the aorta, carotid, hepatic, superior mesenteric, renal and femoral arteries and portal vein was recorded during continuous i.v. infusion of synthetic Substance P (SP) in 8 dogs. Systemic and portal blood pressures were recorded. A significant decrease in mean arterial blood pressure was recorded at infusion of SP in the femoral vein at a rate of 2.5 ng x min-1 x kg b.w.-1 or higher. Portal venous blood pressure increased. A rapid increase in the carotid, hepatic, mesenteric and portal blood flow was obtained at infusion rates of 1.2 ng x min-1 x kg b.w.-1 or higher. The femoral artery responded with a late, transient increase in flow, with a return to the base level while the infusion was still in progress. The renal artery 0lood flow decreased slightly at low infusion rates and increased at higher. At SP infusions in the portal vein the infusion rate had to be increased to 20 ng x min-1 x kg b.w.-1 or higher before any general vascular reactions lere recorded, indicating that the liver has a high capacity for inactivating SP.     

Congenital absence of the portal vein in a middle-aged man

Congenital absence of the portal vein with systemic diversion of mesenteric blood is extremely rare. We report a case of a congenital absence of the portal vein, accidentally discovered in a 59-year-old man, completely asymptomatic and not associated with other malformations or biochemical disorders. Ultrasonography imaging showed the absence of the portal vein and the distal tract of superior mesenteric and splenic veins draining together into a dilated left renal vein. Computed tomography and magnetic resonance confirmed the presence of a congenital portosystemic venous shunt and also revealed two hepatic arteries: one arising from the celiac trunk and the other from the superior mesenteric artery.     

Mast cell inhibition by ketotifen reduces splanchnic inflammatory response in a portal hypertension model in rats

Experimental early prehepatic portal hypertension induces an inflammatory exudative response, including an increased infiltration of the intestinal mucosa and the mesenteric lymph nodes by mast cells and a dilation and tortuosity of the branches of the superior mesenteric vein. The aim of this study is to verify that the prophylactic administration of Ketotifen, a stabilizing drug for mast cells, reduces the consequence of splanchnic inflammatory response in prehepatic portal hypertension. Male Wistar rats were used: Sham-operated and with Triple Partial Portal Vein Ligation, which were subcutaneously administered poly(lactide-co-glycolide) acid microspheres with vehicle 24h before the intervention and SO and rats with Triple Partial Portal Vein Ligation, which were administered Ketotifen-loaded microspheres. Around 48h after surgery, the portal pressure was measured; the levels of chymase (Rat Mast Cell Protease-II) were assayed in the superior mesenteric lymph complex and granulated and degranulated mast cells in the ileum and cecum were quantified. Prophylactic administration of Ketotifen reduced portal pressure, the incidence of dilation and tortuosity of the superior mesenteric vein branches, the amount of Rat Mast Cell Protease-II in the superior mesenteric lymph complex and the number of activated mast cells in the cecum of rats with portal hypertension. In summary, the administration of Ketotifen reduces early splanchnic inflammatory reaction in the rat with prehepatic portal hypertension.     

The intermediate filament proteins of rabbit vascular smooth muscle: immunofluorescent studies of desmin and vimentin

Summary The localization of desmin and vimentin in rabbit vascular smooth muscle was studied using the fluorescent antibody technique. Desmin and vimentin were present in the smooth muscle cells of the portal anterior mesenteric vein, renal vein and renal artery. All endothelial cells and the smooth muscle cells of the abdominal aorta and main pulmonary artery contained only vimentin. The results suggest that desmin and vimentin are differentially distributed in rabbit vascular smooth muscle and that both may occur in a single blood vessel.     

Regional hemodynamic responses to exogenous catecholamines and vasoactive peptides in conscious rats.

The vasoactive hormones vasopressin, angiotensin II, adrenaline, and noradrenaline may all be released after central neural stimulation, but our knowledge of their relative actions on regional vascular resistances is incomplete. A comprehensive account of these patterns will help our understanding of their contributions to centrally generated patterns of blood flow. In the present study, regional blood flows and resistances of five major arteries were measured during sequential intravenous infusions of a range of doses of each substance in conscious rats. Vasopressin strongly increased superior mesenteric, hindquarters, carotid, and renal resistance but did not affect celiac artery resistance until the highest infusion rate. Both angiotensin II and noradrenaline increased resistance, although to different extents, in all vascular beds except the hindquarters, which was unaffected. Adrenaline infused at pressor rates markedly increased superior mesenteric resistance while moderately increasing renal, carotid and celiac arterial resistances. At subpressor rates, however, adrenaline increased celiac resistance but decreased hindquarters vascular resistance without significantly affecting the other beds. It is concluded that each vasoactive substance released into the systemic circulation causes its own characteristic pattern of vascular responses. This information should be useful for understanding the humoral basis of hemodynamic responses to central stimuli.     

Acute effects of captopril on blood pressure and regional blood flows in two types of renovascular hypertensive rats in conscious state

Mean arterial pressure and three regional blood flows--renal, superior mesenteric, and hindquarter flows--were monitored in conscious normotensive control rats (NCR), in two-kidney, one-clip (two-kidney), and in one-kidney, one-clip (one-kidney) hypertensive rats. After administering captopril, an angiotensin-converting enzyme inhibitor, mean arterial pressure decreased in all three groups. However, lowering of arterial pressure was not statistically significant in any of the groups. Renal flow increased significantly in the intact artery of two-kidney hypertensive rats, whereas it did not significantly increase in the clipped artery of one-kidney hypertensive rats and in the intact artery of NCR. Superior mesenteric flow increased significantly only in one-kidney hypertensive rats. Hindquarter flow did not significantly change in the three groups. Regional resistance reduced significantly in not only renal but also in superior mesenteric vascular area in two-kidney hypertensive rats, whereas it did not reduce significantly in these two vascular areas in one-kidney hypertensive rats and in NCR. The present findings show that the renin-angiotensin-mediated vasoconstriction plays a role in not only renal but also in superior mesenteric vascular area in two-kidney hypertensive rats, whereas it hardly plays a role in these three vascular beds in one-kidney hypertensive rats.     

Diverse properties of store-operated TRPC channels activated by protein kinase C in vascular myocytes

In vascular smooth muscle, store-operated channels (SOCs) contribute to many physiological functions including vasoconstriction and cell growth and proliferation. In the present work we compared the properties of SOCs in freshly dispersed myocytes from rabbit coronary and mesenteric arteries and portal vein. Cyclopiazonic acid (CPA)-induced whole-cell SOC currents were sixfold greater at negative membrane potentials and displayed markedly different rectification properties and reversal potentials in coronary compared to mesenteric artery myocytes. Single channel studies showed that endothelin-1, CPA and the cell-permeant Ca(2+) chelator BAPTA-AM activated the same 2.6 pS SOC in coronary artery. In 1.5 mM [Ca(2+)](o) the unitary conductance of SOCs was significantly greater in coronary than in mesenteric artery. Moreover in 0 mM [Ca(2+)](o) the conductance of SOCs in coronary artery was unaltered whereas the conductance of SOCs in mesenteric artery was increased fourfold. In coronary artery SOCs were inhibited by the protein kinase C (PKC) inhibitor chelerythrine and activated by the phorbol ester phorbol 12,13-dibutyrate (PDBu), the diacylglycerol analogue 1-oleoyl-2-acetyl-sn-glycerol (OAG) and a catalytic subunit of PKC. These data infer an important role for PKC in activation of SOCs in coronary artery similar to mesenteric artery and portal vein. Anti-TRPC1 and -TRPC5 antibodies inhibited SOCs in coronary and mesenteric arteries and portal vein but anti-TRPC6 blocked SOCs only in coronary artery and anti-TRPC7 blocked SOCs only in portal vein. Immunoprecipitation showed associations between TRPC1 and TRPC5 in all preparations but between TRPC5 and TRPC6 only in coronary artery and between TRPC5 and TRPC7 only in portal vein. Finally, flufenamic acid increased SOC activity in coronary artery but inhibited SOCs in mesenteric artery and portal vein myocytes. These data provide strong evidence that vascular myocytes express diverse SOC isoforms, which are likely to be composed of different TRPC proteins and have different physiological functions.     

Effect of Substance P on Various Vascular Beds in the Dog

Using the electromagnetic flowmeter technique, the blood flow in the aorta, carotid, hepatic, superior mesenteric, renal and femoral arteries and portal vein was recorded during continuous i.v. infusion of synthetic Substance P (SP) in 8 dogs. Systemic and portal blood pressures were recorded. A significant decrease in mean arterial blood pressure was recorded at infusion of SP in the femoral vein at a rate of 2.5 ng × min^-1× kg b.w.^-1 or higher. Portal venous blood pressure increased. A rapid increase in the carotid, hepatic, mesenteric and portal blood flow was obtained at infusion rates of 1.2 ng × min^-1× kg b.w.^-1 or higher. The femoral artery responded with a late, transient increase in flow, with a return to the base level while the infusion was still in progress. The renal artery blood flow decreased slightly at low infusion rates and increased at higher. At SP infusions in the portal vein the infusion rate had to be increased to 20 ng × min^-1× kg b.w.^-1 or higher before any general vascular reactions were recorded, indicating that the liver has a high capacity for inactivating SP.     

Concurrent aberrant right gastric vein directly draining into the liver and variations of the hepatic artery

We report an autopsy on a 46-year-old man, a case that presented the concurrence of two rare vascular variations of the lesser omentum: aberrant right gastric vein draining directly into the liver, and multiple hepatic arteries. Although the left gastric vein emptied into the left aspect of the portal vein, the right one was found to ascend from the gastric lesser curvature along the right aspect of the common bile duct and to reach directly the porta hepatis. A left hepatic artery originating from the left gastric artery entered the porta hepatis in conjunction with the left ramus of the portal vein. A predominant right hepatic artery arose from the superior mesenteric artery and entered the porta hepatis in conjunction with the right ramus of the portal vein. The proper hepatic artery originating from the celiac artery entered the porta hepatis in conjunction with the aberrant right gastric vein. The possibility of a common underlying mechanism for these rare vascular variations is discussed.     

Organ-specific ligation-induced changes in harmonic components of the pulse spectrum and regional vasoconstrictor selectivity in Wistar rats

It has been shown previously that the amplitudes of the harmonic components of the pulse spectrum vary in specific patterns when the arteries leading to different organs are ligated, with the variations in the harmonics being linearly additive. Since ligation can be regarded as a vast increase in organ resistance, the present study examined the potential of using these ligation-induced variations in the pulse spectrum as reference parameters for an increase in vascular resistance and for regional vasoconstrictor selectivity. A vasoconstrictor, either arginine vasopressin (AVP) or angiotensin II (Ang II), was infused into anaesthetized Wistar rats via the femoral vein for 1 h. The distinct harmonic-specific drug effects on the pulse spectrum were simulated by combining renal artery and superior mesenteric artery ligations in different ratios, the ratio with the lowest mean square difference determining the regional drug selectivity. The ratios indicated that the effect of AVP on the pulse spectrum was attributable to the combined effect of ligating the renal and superior mesenteric arteries, while the effect of Ang II was attributable to ligation of the renal artery. The results are comparable with those of investigations of regional vascular resistance performed using traditional methods. Our findings indicate that the ligation-induced variations in the pulse spectrum can be used to determine regional increases in vascular resistance. This implies that blood pressure can be used as the sole parameter to determine which arterial bed has been affected by the vasoconstrictor, and how seriously.     

A common hepatic artery passing in front of the portal vein

A variation in liver vascularization was discovered in a 50-year-old man. A single common hepatic artery was found to be responsible for vascularization of the entire liver. This artery was unusual in that it formed the first branch of the superior mesenteric artery, crossing the portal trunk shortly after its origin, and passed in front of the portal vein to reach the hilum of the liver, where it divided into a right and a left branch. This artery was a true common hepatic artery because a gastroduodenal artery emerged from it 2 cm after its origin. A common hepatic artery originating from the mesenteric artery and passing in front of the portal vein has never been described before. The patient had a second anatomical variation: the left gastric artery and the splenic artery arose directly from the aorta, without celiac trunk separation. This observation confirms the importance of carrying out a precise vascular assessment before all types of hepatic or pancreatic surgery, to identify possible variations in the number or trajectory of hepatic arteries.With the collaboration of the association Arold (Boulogne, France)     

The effects of intraportl infusions of glucagon on the hepatic arterial and portal venous vascular beds of the dog: Inhibition of hepatic arterial vasoconstrictor responses to noradrenaline

The sympathetically-innervated hepatic arterial and portal venous vascular beds of the dog were perfused simultaneously in situ. Glucagon was infused into the hepatic portal vein (1–10 g/min); it caused increases in hepatic portal vascular resistance and tended to reduce the hepatic arterial vascular resistance. Extrahepatic effects of intraportal infusions of glucagon included increases in superior mesenteric blood flow and heart rate and falls in systemic arterial pressure.A test dose of noradrenaline (10 g) injected into either the hepatic artery or the portal vein caused both hepatic arterial and portal venous vasoconstriction. The hepatic arterial constrictor responses to noradrenaline were antagonized intraportal infusions of glucagon. In contrast, intraportal glucagon did not antagonize the portal constrictor responses to intraarterial or intraportal noradrenaline.Elevated portal blood glucagon concentrations may protect the hepatic arterial blood flow from vasoconstriction due to elevated systemic levels of vasoactive substances including catecholamines.     

Splenic neurohormonal modulation of mesenteric vascular tone

In portal hypertension, development of a hyperdynamic circulation is preceded by transient mesenteric vasoconstriction. Portal hypertension increases splenic venous outflow pressure. We hypothesized that this causes direct reflex activation of mesenteric vasoconstrictor nerves and splenorenal reflex-mediated activation of the renin-angiotensin system. In anaesthetized male rats, we measured mesenteric efferent nerve activity and mesenteric vascular conductance (MVC) after selectively elevating splenic venous pressure. Partial splenic vein occlusion raised splenic venous pressure (from 4.8 ± 0.4 to 24.1 ± 0.3 mmHg; n = 18) and induced a significant increase in mesenteric efferent nerve activity (from 23.2 ± 3.3 to 31.6 ± 3.5 spikes s(-1); n = 11); this response was abolished by prior splenic denervation (from 32.4 ± 2.4 to 31.2 ± 1.6 spikes s(-1); n = 7). Mesenteric vascular conductance, the ratio of superior mesenteric artery blood flow to mean arterial pressure, fell upon splenic vein occlusion (ΔMVC = -0.0120 ± 0.0014 ml min(-1)mmHg(-1); P < 0.05, n = 10). This was attenuated by splenic denervation (ΔMVC = -0.0044 ± 0.0018 ml min(-1)mmHg(-1); P < 0.05, n = 8), but unaffected by mesenteric denervation (ΔMVC = -0.0145 ± 0.0020 ml min(-1)mmHg(-1); n = 6) or bilateral renal denervation (ΔMVC = -0.0106 ± 0.0021 ml min(-1)mmHg(-1); n = 5). Localized blockade of mesenteric vascular angiotensin II type 1 (AT(1)) receptors significantly attenuated the response (ΔMVC = -0.0058 ± 0.0017 ml min(-1)mmHg(-1); P < 0.05, n = 5), whereas blockade of both AT(1) and α(1)-adrenergic receptors caused a significant increase in mesenteric conductance (ΔMVC = +0.0033 ± 0.0010 ml min(-1)mmHg(-1); P < 0.05, n = 6). Our evidence suggests that increased splenic venous outflow pressure reflexly activates adrenergic/angiotensinergic mesenteric nerves, vasodilator mesenteric nerves and the renin-angiotensin system. We propose that obstruction to splenic venous outflow, such as would normally accompany portal hypertension, induces reflex mesenteric vasoconstriction independently of the increase in portal venous pressure.     

A reappraisal of pediatric abdominal surface anatomy

Surface anatomy is fundamental to clinical and surgical practices. As the surface anatomy varies with age, the purpose of this study is to provide age-standardized surface markings for the abdomen in children. A total of 155 abdominal computed tomography scans of healthy children aged 0–18 years were categorized into six groups, and the surface anatomy of the major vascular structures, solid viscera, and anatomical planes in the abdomen was analyzed. The vertebral levels of the celiac trunk, superior mesenteric artery, and hepatic portal vein formation were higher in the youngest age group, whereas the levels of the inferior mesenteric artery, formation of the inferior vena cava, and renal arteries did not differ with age. The right kidney lay between T12 and L3 and the left at T11-L3; however, both kidneys were in lower positions in younger children. The spleen was most commonly located between the 8th and 11th ribs except in toddlers. In all age groups, the hepatic portal vein formation was within the transpyloric plane and the aortic bifurcation was above the supracristal plane. In vivo reassessment of the surface anatomy enables the substantial variability of surface landmarks to be highlighted. This study demonstrates that taking account of age-related variations will increase the accuracy and therefore the clinical relevance of surface anatomy.     

Meal induced changes in hepatic and splanchnic circulation: a noninvasive Doppler study in normal humans

Summary The haemodynamic effects of a meal on the splanchnic and hepatic circulation were evaluated in 30 healthy volunteers, using Doppler ultrasonography. The resistance index (RI) of the superior mesenteric artery and of the left and right intrahepatic arteries, the portal vein blood flow as well as the ratio between maximal velocity in the left and right intrahepatic arteries and the adjacent portal vein were measured initially, then 15, 30, 45, and 60 min after the ingestion of a standard balanced liquid meal. Postprandial haemodynamic changes were maximal 30 min after the meal; at that time, mesenteric artery RI decreased significantly [mean –11% (SEM 14%)] whereas portal vein blood flow increased markedly [mean +79% (SEM 14%)]; a significant increase in hepatic artery RI was observed in both liver lobes. The ratio between maximal velocities of the intrahepatic artery and the intrahepatic portal vein was reduced significantly; this ratio decreased more markedly in the right lobe of the liver. These findings would suggest that there was an adaptation of hepatic artery to portal vein blood flow after a meal. The subsequent increase in intrahepatic portal vein flow velocity was found to be greater in the right lobe of the liver.     

不同途径移植骨髓间充质干细胞改善大鼠肝硬化

背景：骨髓间充质干细胞移植可减轻肝硬化程度,改善肝功能。 目的：观察不同途径移植骨髓间充质干细胞对四氯化碳诱导大鼠肝硬化的作用。 方法：将60只SD大鼠随机分为正常组、对照组、门静脉移植组、肝动脉移植组、尾静脉移植组,后4组采用四氯化碳联合乙醇制作肝硬化模型,对照组不进行移植,其余3组分别经门静脉、肝动脉、尾静脉移植大鼠骨髓间充质干细胞1×10⁶。 结果与结论：移植4周后,与对照组比较,移植3组大鼠肝功能均得到明显改善,血清白蛋白、胆碱酯酶显著升高(P < 0.05),转氨酶、胆红素、凝血时间、Ⅳ型胶原显著降低(P < 0.05),肝纤维化程度显著减轻(P < 0.05)。门静脉移植组及肝动脉移植组优于尾静脉移植组,前两者之间差异无显著性意义(P > 0.05)。说明经门静脉、肝动脉、尾静脉移植骨髓间充质干细胞均可减轻肝纤维化程度,改善肝功能,但肝动脉及门静脉移植途径优于外周血静脉途径。     

Portal and aortic blood sampling technique in unrestrained rats

A composite cannula has been designed to permit blood sampling from the distal aorta and portal vein in unanesthetized, unrestrained rats. The aortic and portal cannulas were constructed from polyvinylchloride (PVC) tubing drawn to a fine tip and fused to polyethylene tubing (PE 50). The portal vein was cannulated via a mesenteric vein. The abdominal aorta was cannulated non-occlusively. Both vascular cannulas were securely tied to the abdominal wall. A silicone rubber duodenal cannula was inserted into the membraneous portion of the stomach and passed into the duodenal lumen. Its end was tunnelled under the skin to the rat's back and placed under a wound clip. The utility of these cannulas was illustrated by simultaneous sampling of aortic and portal vein blood during absorption of labelled amino acids. These chronic cannulas can be used to study behavioral or physiologic parameters while selectively infusing compounds into the duodenum or portal vein. The aortic cannula can be used to measure mean arterial blood pressure, to sample blood, or to infuse the caudal part of the rat.