Hemodynamic significance of the carotid rete during changes in arterial blood pressure

1988 ◽  
Vol 254 (5) ◽  
pp. R770-R775
Author(s):  
G. Dieguez ◽  
A. L. Garcia-Villalon ◽  
B. Gomez ◽  
S. Lluch
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Smooth Muscle ◽  
Inferior Vena Cava ◽  
Inferior Vena ◽  
Vena Cava ◽  
Brain Vessels ◽  
Afferent Limb ◽  
Active Relaxation ◽  
Arterial Blood

We attempted to characterize in the goat the hemodynamic response of the carotid rete during large, passive changes in blood pressure in the afferent limb of the rete produced by mechanical constriction of the thoracic aorta or the inferior vena cava. Experiments in 12 anesthetized goats demonstrated that calculated resistance through the rete decreases in hypertension and increases in hypotension, whereas changes in resistance through brain vessels follow opposite directions. The consequence of this is that the carotid rete, by passively decreasing its resistance to blood flow in hypertension, acts as a flow-facilitating system in a situation in which smooth muscle of brain vessels contracts in response to stretch. Contrariwise, by increasing its resistance to blood flow during systemic hypotension, the carotid rete "limits" the passage of blood when active relaxation of brain vessels takes place.

Preferential streaming of ductus venosus blood to the brain and heart in fetal lambs

1979 ◽  
Vol 237 (6) ◽  
pp. H724-H729 ◽  
Author(s):  
D. I. Edelstone ◽  
A. M. Rudolph
Keyword(s):  
Blood Flow ◽  
Inferior Vena Cava ◽  
Inferior Vena ◽  
Vena Cava ◽  
Ductus Venosus ◽  
Inferior Vena Caval ◽  
Blood Samples ◽  
Blood Flows ◽  
Arterial Blood ◽  
The Brain

In 16 chronically prepared fetal lambs we compared the systemic distribution of ductus venosus blood flow with that of abdominal inferior vena caval blood by simultaneously injecting microspheres labeled with different radionuclides into an umbilical vein and into the abdominal inferior vena cava. A significantly greater proportion of ductus venosus blood flow than of abdominal inferior vena caval blood flow supplied the brain, heart, and upper body; this resulted from streaming of ductus venosus blood flow within the thoracic inferior vena cava with preferential direction of that blood flow through the foramen ovale. Blood flows to upper and lower body structures and placenta calculated from umbilical venous microsphere injections and reference arterial blood samples did not differ from those computed fromabdominal inferior vena caval injections and reference samples. Thus, despite streamline blood flow within the fetal thoracic inferior vena cava, organ blood flows can be accurately measured with either an umbilical venous or an abdominal inferior vena caval injection of microspheres when either is combined with the appropriate reference arterial blood samples.

scholarly journals 5-HT causes splanchnic venodilation

2017 ◽  
Vol 313 (3) ◽  
pp. H676-H686 ◽  
Author(s):  
Bridget M. Seitz ◽  
Hakan S. Orer ◽  
Teresa Krieger-Burke ◽  
Emma S. Darios ◽  
Janice M. Thompson ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Inferior Vena Cava ◽  
Portal Vein ◽  
Superior Mesenteric Vein ◽  
Inferior Vena ◽  
Vena Cava ◽  
Receptor Protein ◽  
Mesenteric Vein

Serotonin [5-hydroxytryptamine (5-HT)] causes relaxation of the isolated superior mesenteric vein, a splanchnic blood vessel, through activation of the 5-HT7 receptor. As part of studies designed to identify the mechanism(s) through which chronic (≥24 h) infusion of 5-HT lowers blood pressure, we tested the hypothesis that 5-HT causes in vitro and in vivo splanchnic venodilation that is 5-HT7 receptor dependent. In tissue baths for measurement of isometric contraction, the portal vein and abdominal inferior vena cava relaxed to 5-HT and the 5-HT1/7 receptor agonist 5-carboxamidotryptamine; relaxation was abolished by the 5-HT7 receptor antagonist SB-269970. Western blot analyses showed that the abdominal inferior vena cava and portal vein express 5-HT7 receptor protein. In contrast, the thoracic vena cava, outside the splanchnic circulation, did not relax to serotonergic agonists and exhibited minimal expression of the 5-HT7 receptor. Male Sprague-Dawley rats with chronically implanted radiotelemetry transmitters underwent repeated ultrasound imaging of abdominal vessels. After baseline imaging, minipumps containing vehicle (saline) or 5-HT (25 μg·kg−1·min−1) were implanted. Twenty-four hours later, venous diameters were increased in rats with 5-HT-infusion (percent increase from baseline: superior mesenteric vein, 17.5 ± 1.9; portal vein, 17.7 ± 1.8; and abdominal inferior vena cava, 46.9 ± 8.0) while arterial pressure was decreased (~13 mmHg). Measures returned to baseline after infusion termination. In a separate group of animals, treatment with SB-269970 (3 mg/kg iv) prevented the splanchnic venodilation and fall in blood pressure during 24 h of 5-HT infusion. Thus, 5-HT causes 5-HT7 receptor-dependent splanchnic venous dilation associated with a fall in blood pressure. NEW & NOTEWORTHY This research is noteworthy because it combines and links, through the 5-HT7 receptor, an in vitro observation (venorelaxation) with in vivo events (venodilation and fall in blood pressure). This supports the idea that splanchnic venodilation plays a role in blood pressure regulation.

Dose-dependent thrombus resolution due to oral plasminogen activator inhibitor (PAI)-1 inhibition with tiplaxtinin in a rat stenosis model of venous thrombosis

2008 ◽  
Vol 99 (04) ◽  
pp. 749-758 ◽  
Author(s):  
Sanjiv Baxi ◽  
David Crandall ◽  
Thomas Meier ◽  
Shirley Wrobleski ◽  
Angela Hawley ◽  
...  
Keyword(s):  
Blood Flow ◽  
Inferior Vena Cava ◽  
Venous Thrombosis ◽  
Inferior Vena ◽  
Phase 1 ◽  
Vena Cava ◽  
Phase 2 ◽  
Oral Gavage ◽  
Dose Dependent ◽  
Pai 1

SummaryThis study aimed to evaluate a small-molecule PAI-1 inhibitor (PAI-039; tiplaxtinin) in a rodent stenosis model of venous thrombosis in a two-phase experiment. Phase 1 determined the efficacy of tiplaxtinin against Lovenox (LOV), while phase 2 determined the dose-dependent efficacy. For both phases, drug treatment began 24 hours after surgically induced venous thrombosis and continued for four days. Phase 1 animals (n = 24) receiving low-dose (LD; 1 mg/kg oral gavage) PAI-1 inhibitor demonstrated a 52% decrease in thrombus weight (TW) versus controls (p < 0.05) with significant reductions in active plasma PAI-1, while the high-dose (HD; 10 mg/kg oral gavage) group demonstrated a 23% reduction in TW versus controls. Animals treated subcutaneously with LOV (3 mg/kg) showed a 39% decrease in TW versus controls (p < 0.05). Coagulation tests (aPTT and TCT) were significantly different in LOV compared to PAI-1 inhibitor groups. PAI-039 treatment was also associated with significantly increased return of inferior vena cava blood flow four days post-thrombosis versus controls (p < 0.05). In phase 2 (n = 30), TW was reduced from the 0.5 mg/kg to 5 mg/ kg experimental groups, with the 10 mg/kg group demonstrating a paradoxical increase. The 5 mg/kg group showed statistically significant decreases in TW versus controls after four treatment days (p < 0.05). This is the first study to demonstrate dose related effects of PAI-039 on increasing thrombus resolution and inferior vena cava blood flow without adverse effects on anti-coagulation in a rat stenosis model of venous thrombosis.

125 Numerical Study of Blood Flow in the Hepatic Portion of the Inferior Vena Cava on Budd-Chiari Syndrome

2008 ◽  
Vol 2007.20 (0) ◽  
pp. 257-258
Author(s):  
Mizuho MATSUBARA ◽  
Masao WATANABE ◽  
Satoshi WATANABE ◽  
Kozo KONISHI ◽  
Makoto HASHIZUME
Keyword(s):  
Blood Flow ◽  
Inferior Vena Cava ◽  
Inferior Vena ◽  
Numerical Study ◽  
Vena Cava ◽  
Budd Chiari Syndrome ◽  
Chiari Syndrome

scholarly journals Primary Smooth Muscle Tumors of the Inferior Vena Cava

1971 ◽  
Vol 174 (6) ◽  
pp. 1009-1018 ◽  
Author(s):  
R. C. Wray ◽  
Howard Dawkins
Keyword(s):  
Smooth Muscle ◽  
Inferior Vena Cava ◽  
Inferior Vena ◽  
Vena Cava ◽  
Smooth Muscle Tumors

scholarly journals The electrolytic inferior vena cava model (EIM) to study thrombogenesis and thrombus resolution with continuous blood flow in the mouse

2013 ◽  
Vol 109 (06) ◽  
pp. 1158-1169 ◽  
Author(s):  
Christine M. Alvarado ◽  
Shirley K. Wrobleski ◽  
Dallas W. Slack ◽  
Angela E. Hawley ◽  
Diana M. Farris ◽  
...  
Keyword(s):  
Blood Flow ◽  
Inferior Vena Cava ◽  
Inferior Vena ◽  
Copper Wire ◽  
Vena Cava ◽  
Electrical Current ◽  
Strong Positive Correlation ◽  
Vein Wall ◽  
Time Points ◽  
Ivc Thrombus

SummaryPreviously, we presented the electrolytic inferior vena cava (IVC) model (EIM) during acute venous thrombosis (VT). Here, we present our evaluation of the EIM for chronic VT time points in order to determine whether this model allows for the study of thrombus resolution. C57BL/6 mice (n=191) were utilised. In this model a copper-wire, inserted into a 25-gauge needle, is placed in the distal IVC and another subcutaneously. An electrical current (250 Amp/15 minutes) activates the endothelial cells, inducing thrombogenesis. Ultrasound, thrombus weight (TW), vein wall leukocyte counts, vein wall thickness/ fibrosis scoring, thrombus area and soluble P-selectin (sP-sel) were performed at baseline, days 1, 2, 4, 6, 9, 11 and 14, post EIM. A correlation between TW and sP-sel was also determined. A thrombus formed in each mouse undergoing EIM. Blood flow was documented by ultrasound at all time points. IVC thrombus size increased up to day 2 and then decreased over time, as shown by ultrasound, TW, and sP-sel levels. TW and sP-sel showed a strong positive correlation (r=0.48, p<0.0002). Vein wall neutrophils were the most common cell type present in acute VT (up to day 2) with monocytes becoming the most prevalent in chronic VT (from day 6 to day 14). Thrombus resolution was demonstrated by ultrasound, TW and thrombus area. In conclusion, the EIM produces a non-occlusive and consistent IVC thrombus, in the presence of constant blood flow, allowing for the study of VT at both acute and chronic time points. Thrombus resolution was demonstrated by all modalities utilised in this study.Note: Results were presented, in part, at the 24th American Venous Forum Annual Meeting 2012 in Orlando, FL, USA.

Sources of Human Plasma Cyclic AMP. Examinations before and after Beta2 Adrenergic Stimulation

1981 ◽  
Vol 9 (6) ◽  
pp. 521-525 ◽  
Author(s):  
Peter Endres ◽  
Christine Klock ◽  
Rolf Günther
Keyword(s):  
Cyclic Amp ◽  
Inferior Vena Cava ◽  
Right Ventricle ◽  
Subcutaneous Injection ◽  
Inferior Vena ◽  
Vena Cava ◽  
Adrenergic Stimulation ◽  
Arterial Blood ◽  
Before And After ◽  
General Influence

Plasma cyclic AMP was measured in different vessels in seventeen volunteers before and after stimulation with terbutaline. Differences between arterial blood and blood from the hepatic vein, right ventricle, inferior vena cava and a cubital vein could not be demonstrated. Only in the renal vein was the concentration of cyclic AMP decreased. Our results indicate that cyclic AMP is not generated from any specific isolated organ and that changes in cyclic AMP after subcutaneous injection of terbutaline reflect a general influence of this drug.

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