Control of hepatic arterial blood flow: independence from liver metabolic activity

1980 ◽  
Vol 239 (4) ◽  
pp. H559-H559 ◽  
Author(s):  
W. Wayne Lautt
Keyword(s):  
Blood Flow ◽  
Metabolic Activity ◽  
Hepatic Blood Flow ◽  
Venous Blood ◽  
Arterial Blood Flow ◽  
Hepatic Veins ◽  
Venous Blood Flow ◽  
Hepatic Arterial Blood Flow ◽  
Arterial Blood ◽  
Total Hepatic Blood Flow

This investigation tested the hypothesis that hepatic arterial blood flow is not dependent on hepatic metabolism, but rather is controlled in a manner that tends to maintain total hepatic blood flow constant. Cats anesthetized with pentobarbital sodium received SKF 525 A or 2,4-dinitrophenol (DNP), respectively, to inhibit or stimulate metabolism. Blood flows and oxygen uptake of the liver and gut were determined by use of a hepatic venous long circuit and noncannulating electromagnetic recording of hepatic arterial blood flow. In both sets of experiments the hepatic arterial blood flow. In both sets of experiments the hepatic artery constricted sufficiently to offset elevated portal venous blood flow, thereby maintaining total hepatic blood flow constant. The reduced hepatic arterial conductance occurred with DNP despite elevated metabolic rate and reduced oxygen in the portal and hepatic veins. Altered gut metabolism correlated with altered vascular conductance in the gut; hepatic arterial conductance changes did not correlate with changes in liver metabolic activity. The data confirmed the hypothesis. It is suggested that for hormonal homeostatis it is essential that total hepatic blood flow be regulated because hepatic clearance is flow dependent.

Liver blood flow and oxygen consumption during hypocapnia and IPPV in the greyhound

1979 ◽  
Vol 47 (2) ◽  
pp. 290-295 ◽  
Author(s):  
R. L. Hughes ◽  
R. T. Mathie ◽  
W. Fitch ◽  
D. Campbell
Keyword(s):  
Blood Flow ◽  
Oxygen Consumption ◽  
Airway Pressure ◽  
Venous Blood ◽  
Liver Blood Flow ◽  
Arterial Blood Flow ◽  
Venous Blood Flow ◽  
Hepatic Arterial Blood Flow ◽  
Arterial Blood ◽  
Intermittent Positive Pressure Breathing

Pentobarbital-anesthetized greyhounds were passively hyperventilated using intermittent positive-pressure breathing (IPPV) and the effects of raised airway pressure, accompanied by hypocapnia and then by normocapnia, on liver blood flow and oxygen consumption were studied. Electromagnetic flowmeters were used to measure hepatic arterial, portal venous, and splenic venous blood flow. Studies were carried out at three levels of raised airway pressure, both at normocapnia and hypocapnia. It was found that hypocapnic hyperventilation produced a decrease in portal venous and hepatic arterial blood flow. Normocapnic hyperventilation resulted in a restoration of portal venous blood flow but with a further decrease in hepatic arterial blood flow. A decrease in oxygen consumption with hypocapnia, returning to control values with normocapnia, was seen. It is suggested that the reduction in liver blood flow and oxygen consumption seen with passive hyperventilation is chiefly an effect of hypocapnia and is largely reversed by restoration of normocapnia.

Liver Blood Flow and Oxygen Consumption during Metabolic Acidosis and Alkalosis in the Greyhound

1981 ◽  
Vol 60 (4) ◽  
pp. 355-361 ◽  
Author(s):  
R. L. Hughes ◽  
R. T. Mathie ◽  
W. Fitch ◽  
D. Campbell
Keyword(s):  
Blood Flow ◽  
Oxygen Consumption ◽  
Venous Blood ◽  
Liver Blood Flow ◽  
Arterial Blood Flow ◽  
Venous Blood Flow ◽  
Hepatic Arterial Blood Flow ◽  
Portal Venous Blood Flow ◽  
Arterial Blood ◽  
Portal Venous Blood

1. Hepatic arterial and portal venous blood flow and hepatic oxygen consumption were measured in two groups of greyhounds anaesthetized with pentobarbitone. Flows were measured with electromagnetic flowmeters. 2. In the first group the effects of metabolic acidosis produced by the infusion of a molar solution of lactic acid were studied. In the second group the effects of metabolic alkalosis produced by the infusion of a molar solution of sodium bicarbonate were studied. 3. In the acidotic group hepatic arterial blood flow decreased from 35.2 to 9.6 ml min− 100 g− of liver whereas portal venous blood flow increased from 94.2 to 126.1 ml min− 100 g− of liver. Total liver blood flow was unchanged. Hepatic oxygen consumption increased, but not significantly, while hepatic venous oxygen content decreased significantly. Hepatic arterial resistance increased from 1.18 to 2.77 mmHg min− ml− while peripheral resistance was virtually unchanged. Portal venous pressure increased from 7.08 to 11.6 mmHg. 4. In the alkalotic group portal venous blood flow increased from 112 to 137 ml min− 100 g− of liver. Hepatic arterial blood flow increased, but not significantly. Total liver blood flow increased from 151 to 185, ml min− 100 mg− of liver. There were no significant changes in hepatic oxygen consumption. 5. It is concluded that metabolic acidosis reduces the supply of oxygen to the liver owing to the reduction in hepatic arterial blood flow and is therefore potentially harmful, whereas metabolic alkalosis probably has no biologically significant effect on liver blood flow.

General anesthesia and hepatic circulation

1987 ◽  
Vol 65 (8) ◽  
pp. 1762-1779 ◽  
Author(s):  
Simon Gelman
Keyword(s):  
Blood Flow ◽  
General Anesthesia ◽  
Surgical Procedures ◽  
Hepatic Blood Flow ◽  
Portal Blood Flow ◽  
Arterial Blood Flow ◽  
Hepatic Circulation ◽  
Arterial Blood ◽  
Total Hepatic Blood Flow ◽  
Circulatory Disturbances

This article describes hepatic circulatory disturbances associated with anesthesia and surgical intervention. The material is presented in three parts: part 1 describes the effects of general anesthetics on the hepatic circulation; part 2 deals with different factors related to surgical procedures and anesthesia; and part 3 analyzes the role of hepatic circulatory disturbances and hepatic oxygen deprivation in anesthesia-induced hepatotoxicity. The analysis of available data suggests that general anesthesia affects the splanchnic and hepatic circulation in various directions and to different degrees. The majority of anesthetics decreases portal blood flow in association with a decrease in cardiac output. However, hepatic arterial blood flow can be preserved, decreased, or increased. The increase in hepatic arterial blood flow, when it occurs, is usually not enough to compensate for a decrease in portal blood flow and therefore total hepatic blood flow is usually decreased during anesthesia. This decrease in total hepatic blood flow-has certain pharmacokinetic implications, namely a decrease in clearance of endogenous and exogenous substances with a high hepatic extraction ratio. On the other hand, a reduction in the hepatic oxygen supply might play a certain role in liver dysfunction occurring perioperatively. Surgical procedures–preparations combined with anesthesia have a very complex effect on the splanchnic and hepatic circulation. Within this complex, the surgical procedure–preparation plays the main role in developing circulatory disturbances, while anesthesia plays only a modifying role. Hepatic oxygen deprivation may play an important role in anesthesia-induced hepatotoxicity in different experimental models.

Role of glucagon in splanchnic hyperemia of chronic portal hypertension

1986 ◽  
Vol 251 (5) ◽  
pp. G674-G677 ◽  
Author(s):  
J. N. Benoit ◽  
B. Zimmerman ◽  
A. J. Premen ◽  
V. L. Go ◽  
D. N. Granger
Keyword(s):  
Blood Flow ◽  
Portal Hypertension ◽  
Venous Blood ◽  
Reference Sample ◽  
Venous Hypertension ◽  
Arterial Blood Flow ◽  
Venous Blood Flow ◽  
Portal Vein Stenosis ◽  
Arterial Blood

The role of glucagon as a blood-borne mediator of the hyperdynamic circulation associated with chronic portal venous hypertension was assessed in the rat portal vein stenosis model. Selective removal of pancreatic glucagon from the circulation was achieved by intravenous infusion of a highly specific glucagon antiserum. Blood flow to splanchnic organs, kidneys, and testicles was measured with radioactive microspheres, and the reference-sample method. Glucagon antiserum had no effect on blood flow in the gastrointestinal tract of sham-operated (control) rats. However, the antiserum produced a significant reduction in hepatic arterial blood flow in the control rats, suggesting that glucagon contributes significantly to the basal tone of hepatic arterioles. In portal hypertensive rats glucagon antiserum significantly reduced blood flow to the stomach (22%), duodenum (25%), jejunum (24%), ileum (26%), cecum (27%), and colon (26%). Portal venous blood flow was reduced by approximately 30%. The results of this study support the hypothesis that glucagon mediates a portion of the splanchnic hyperemia associated with chronic portal hypertension.

Effects of systemic arterial hypoperfusion on splanchnic hemodynamics and hepatic arterial buffer response in pigs

2001 ◽  
Vol 280 (5) ◽  
pp. G819-G827 ◽  
Author(s):  
S. M. Jakob ◽  
J. J. Tenhunen ◽  
S. Laitinen ◽  
A. Heino ◽  
E. Alhava ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiac Tamponade ◽  
Venous Blood ◽  
Liver Blood Flow ◽  
Hepatic Function ◽  
Arterial Blood Flow ◽  
Cellular Damage ◽  
Aortic Blood Flow ◽  
Venous Blood Flow ◽  
Arterial Blood

The hepatic arterial buffer response (HABR) tends to maintain liver blood flow under conditions of low mesenteric perfusion. We hypothesized that systemic hypoperfusion impairs the HABR. In 12 pigs, aortic blood flow was reduced by cardiac tamponade to 50 ml · kg−1 · min−1 for 1 h (short-term tamponade) and further to 30 ml · kg−1 · min−1 for another hour (prolonged tamponade). Twelve pigs without tamponade served as controls. Portal venous blood flow decreased from 17 ± 3 (baseline) to 6 ± 4 ml · kg−1 · min−1 (prolonged tamponade; P = 0.012) and did not change in controls, whereas hepatic arterial blood flow decreased from 2 ± 1 (baseline) to 1 ± 1 ml · kg−1 · min−1 (prolonged tamponade; P = 0.050) and increased from 2 ± 1 to 4 ± 2 ml · kg−1 · min−1in controls ( P = 0.002). The change in hepatic arterial conductance (Δ C ha) during acute portal vein occlusion decreased from 0.1 ± 0.05 (baseline) to 0 ± 0.01 ml · kg−1 · min−1 · mmHg−1(prolonged tamponade; P = 0.043). In controls, Δ C ha did not change. Hepatic lactate extraction decreased, but hepatic release of glutathione S-transferase A did not change during cardiac tamponade. In conclusion, during low systemic perfusion, the HABR is exhausted and hepatic function is impaired without signs of cellular damage.

Increase in hepatic blood flow during early sepsis is due to increased portal blood flow

1991 ◽  
Vol 261 (6) ◽  
pp. R1507-R1512 ◽  
Author(s):  
P. Wang ◽  
Z. F. Ba ◽  
I. H. Chaudry
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Hepatic Blood Flow ◽  
Portal Blood Flow ◽  
Portal Blood ◽  
Arterial Blood Flow ◽  
Blood Flows ◽  
Arterial Blood ◽  
Total Hepatic Blood Flow ◽  
Early Sepsis

Although hepatic blood flow increases significantly during early sepsis [as produced by cecal ligation and puncture (CLP)], it is not known whether this is due to the increase in portal or hepatic arterial blood flows. To study this, rats were subjected to CLP, after which they and sham-operated rats received either 3 or 6 ml normal saline/100 g body wt subcutaneously (i.e., all rats received crystalloid therapy). Blood flow in various organs was determined by using a radioactive microsphere technique at 5 and 20 h after CLP or sham operation. Portal blood flow was calculated as the sum of blood flows to the spleen, pancreas, gastrointestinal tract, and mesentery. Total hepatic blood flow was the sum of portal blood flow and hepatic arterial blood flow. A significant increase in portal blood flow and in total hepatic blood flow was observed at 5 h after CLP (i.e., early sepsis), and this was not altered by doubling the volume of crystalloid resuscitation after the induction of sepsis. In contrast, hepatic arterial blood flow during early sepsis was found to be similar to control; however, it was significantly reduced in late sepsis (i.e., 20 h after CLP). Cardiac output was significantly higher than the control in early sepsis. However, even in late sepsis, cardiac output and total hepatic blood flow were not significantly different from controls. These results indicate that the increased total hepatic blood flow during early hyperdynamic sepsis is solely due to the increased portal blood flow.

Splenic baroreceptors control splenic afferent nerve activity

2006 ◽  
Vol 290 (2) ◽  
pp. R352-R356 ◽  
Author(s):  
Karli Moncrief ◽  
Susan Kaufman
Keyword(s):  
Blood Flow ◽  
Venous Pressure ◽  
Venous Blood ◽  
Splenic Vein ◽  
Afferent Nerve ◽  
Arterial Blood Flow ◽  
Venous Blood Flow ◽  
Nerve Activity ◽  
Vein Occlusion ◽  
Arterial Blood

Stenosis of either the portal or splenic vein increases splenic afferent nerve activity (SANA), which, through the splenorenal reflex, reduces renal blood flow. Because these maneuvers not only raise splenic venous pressure but also reduce splenic venous outflow, the question remained as to whether it is increased intrasplenic postcapillary pressure and/or reduced intrasplenic blood flow, which stimulates SANA. In anesthetized rats, we measured the changes in SANA in response to partial occlusion of either the splenic artery or vein. Splenic venous and arterial pressures and flows were simultaneously monitored. Splenic vein occlusion increased splenic venous pressure (9.5 ± 0.5 to 22.9 ± 0.8 mmHg, n = 6), reduced splenic arterial blood flow (1.7 ± 0.1 to 0.9 ± 0.1 ml/min, n = 6) and splenic venous blood flow (1.3 ± 0.1 to 0.6 ± 0.1 ml/min, n = 6), and increased SANA (1.7 ± 0.4 to 2.2 ± 0.5 spikes/s, n = 6). During splenic artery occlusion, we matched the reduction in either splenic arterial blood flow (1.7 ± 0.1 to 0.7 ± 0.05, n = 6) or splenic venous blood flow (1.2 ± 0.1 to 0.5 ± 0.04, n = 5) with that seen during splenic vein occlusion. In neither case was there any change in either splenic venous pressure (−0.4 ± 0.9 mmHg, n = 6 and +0.1 ± 0.3 mmHg, n = 5) or SANA (−0.11 ± 0.15 spikes/s, n = 6 and −0.05 ± 0.08 spikes/s, n = 5), respectively. Furthermore, there was a linear relationship between SANA and splenic venous pressure ( r = 0.619, P = 0.008, n = 17). There was no such relationship with splenic venous ( r = 0.371, P = 0.236, n = 12) or arterial ( r = 0.275, P = 0.413, n = 11) blood flow. We conclude that it is splenic venous pressure, not flow, which stimulates splenic afferent nerve activity and activates the splenorenal reflex in portal and splenic venous hypertension.

Mechanism and role of intrinsic regulation of hepatic arterial blood flow: hepatic arterial buffer response

1985 ◽  
Vol 249 (5) ◽  
pp. G549-G556 ◽  
Author(s):  
W. W. Lautt
Keyword(s):  
Blood Flow ◽  
Portal Blood Flow ◽  
Arterial Blood Flow ◽  
Portal Flow ◽  
Hepatic Arterial Blood Flow ◽  
Arterial Blood ◽  
Total Hepatic Blood Flow ◽  
Flow Changes ◽  
Arterial Dilation ◽  
O2 Supply

Hepatic parenchymal cell metabolic status does not control the hepatic arterial blood flow. Portal blood flow is a major intrinsic regulator of hepatic arterial tone. Hepatic arterial blood flow changes so as to buffer the impact of portal flow alterations on total hepatic blood flow, thus tending to regulate total hepatic flow at a constant level. This response is called the "hepatic arterial buffer response." The mechanism of the arterial buffer response seems to depend on portal blood flow washing away local concentrations of adenosine (production may be constant) from the area of the arterial resistance site. If portal flow decreases, less adenosine is washed away and the local concentration rises resulting in arterial dilation. Putative roles. Hepatic clearance of many hormones and endogenous compounds is blood flow limited. Constancy of total hepatic blood flow is crucial to homeostasis, and severe changes in the magnitude of flow can rapidly alter plasma concentrations of such compounds. The buffer may also prevent portal flow changes from severely altering intrahepatic blood pressures and liver blood volume. Pathological implications. If the O2 supply-to-demand ratio becomes too low, as in the case of a hypermetabolic liver (chronic alcohol exposure), a state of tissue hypoxia can exist without producing hepatic arterial dilation. Therapeutic implications. Livers show protection and improved recovery from several toxic agents, including alcohol, if the O2 supply-to-demand ratio can be increased. Arterial dilation by means of intra-arterial or intra-portal adenosine may prove useful.

Method for measuring hepatic uptake of oxygen or other blood-borne substances in situ

1976 ◽  
Vol 40 (2) ◽  
pp. 269-274 ◽  
Author(s):  
W. W. Lautt
Keyword(s):  
Blood Flow ◽  
Venous Blood ◽  
Hepatic Uptake ◽  
Arterial Blood Flow ◽  
Venous Blood Flow ◽  
Similar Data ◽  
Blood Samples ◽  
Arterial Blood ◽  
Hepatic Hemodynamics

A preparation is described by which hepatic arterial blood flow and portal venous blood flow can be accurately and continuously measured while simultaneously providing a method by which multiple blood samples can be taken from the hepatic artery, portal vein, and hepatic vein without disrupting hepatic hemodynamics or causing hemodilution. By this means hepatic uptake or release of blood-borne substances can be measured in situ and correlated with hemodynamic parameters. In 13 splenectomized cats, oxygen uptake by the denervated liver was 4.5 +/- 0.3 ml . min-1. 100 g-1 of tissue, representing 54% of total oxygen removed by the splanchnic bed. The hepatic hemodynamics determined by this method are similar to those reported by others in vivo and the metabolic state of the liver remained stable for at least 2 h during which an average of 29 blood samples were taken. Advantages of this preparation over other methods of obtaining similar data are discussed.

Differential effects of ATP-MgCl2 on portal and hepatic arterial blood flow after hemorrhage and resuscitation

1992 ◽  
Vol 263 (6) ◽  
pp. G895-G900 ◽  
Author(s):  
P. Wang ◽  
Z. F. Ba ◽  
I. H. Chaudry
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Hepatic Blood Flow ◽  
Portal Blood Flow ◽  
Portal Blood ◽  
Arterial Blood Flow ◽  
Shed Blood ◽  
Hepatic Arterial Blood Flow ◽  
Arterial Blood ◽  
Small Intestinal

Although ATP-MgCl2 administration after hemorrhage and resuscitation restores the decreased hepatic blood flow, it is not known whether this is due to the increase in portal blood flow or hepatic arterial blood flow. To study this, rats underwent a midline laparotomy (i.e., trauma induced) and were bled to and maintained at a mean arterial pressure of 40 mmHg until 40% of maximal shed blood volume was returned in the form of Ringer lactate (RL). The animals were resuscitated with four times the volume of the shed blood with RL, during and after which ATP-MgCl2 (50 mumol/kg body wt) or an equal volume of normal saline was infused intravenously over 95 min. Cardiac output and organ blood flow were determined by 85Sr-labeled microspheres at 90 min after the completion of resuscitation. The results indicate that portal blood flow and total hepatic blood flow decreased significantly after hemorrhage and resuscitation. ATP-MgCl2 treatment, however, restored these parameters to sham values. In contrast, hepatic arterial blood flow did not change significantly after either hemorrhage and resuscitation or ATP-MgCl2 infusion. Moreover, the depressed cardiac output was normalized and coronary blood flow was higher than shams after ATP-MgCl2 treatment. Unlike small intestinal blood flow, blood flows to the stomach, spleen, pancreas, mesentery, and cecum were not markedly affected with ATP-MgCl2 infusion. Thus the restoration of hepatic blood flow with ATP-MgCl2 treatment under such conditions is due to the increased portal blood flow, i.e., solely due to the increased small intestinal blood flow.

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