The importance of nervous and humoral factors in the control of vascular resistance, blood flow distribution and net fluid absorption in the cat small intestine during hemorrhage

1984 ◽  
Vol 121 (4) ◽  
pp. 305-315 ◽  
Author(s):  
STAFFAN REDFORS ◽  
HENRIK SJÖVALL
Keyword(s):  
Blood Flow ◽  
Small Intestine ◽  
Vascular Resistance ◽  
Flow Distribution ◽  
Blood Flow Distribution ◽  
Fluid Absorption ◽  
Humoral Factors

Effect of lung thromboxane generation on regional blood flow during sheep bypass

1982 ◽  
Vol 242 (3) ◽  
pp. H462-H469
Author(s):  
A. H. Schuette ◽  
P. C. Huttemeier ◽  
W. D. Watkins ◽  
W. M. Zapol
Keyword(s):  
Blood Flow ◽  
Vascular Resistance ◽  
Regional Blood Flow ◽  
Flow Distribution ◽  
Pulmonary Artery Hypertension ◽  
Blood Flow Distribution ◽  
Systemic Blood ◽  
Systemic Blood Flow ◽  
Pulmonary Vasoconstriction ◽  
Potent Vasoconstrictor

Acute pulmonary artery hypertension and an increased plasma concentration of thromboxane B2 (TXB2), the stable metabolite of the potent vasoconstrictor thromboxane A2, occur within minutes of the onset of venovenous (VV) partial bypass in the awake sheep. To search for systemic vasoconstriction, we assessed systemic blood flow distribution by radioactive microspheres and correlated the changes to alterations in plasma TXB2 and 6-keto-F1 alpha concentration. In 10 control sheep mean plasma TXB2 concentration increased from 0.39 ng/ml prebypass to about 1.1 ng/ml at 8 and 16 min of bypass. Despite marked pulmonary vasoconstriction with a threefold elevated resistance, the blood flow to the heart, brain, and kidney were unchanged at 8 and 16 min of bypass. However, hepatic vascular resistance increased twofold at 8 min of bypass. Indomethacin treatment (10 mg/kg) of six sheep blocked the increase of both pulmonary and hepatic vascular resistance as well as reduced TXB2 levels below 0.1 ng/ml. Thus VV bypass induces transient and selective vasoconstriction of the lung and liver mediated by vasoconstrictor eicosanoids.

Systemic and uterine blood flow distribution during prolonged infusion of 17β-estradiol

1998 ◽  
Vol 275 (3) ◽  
pp. H731-H743 ◽  
Author(s):  
Ronald R. Magness ◽  
Terrance M. Phernetton ◽  
Jing Zheng
Keyword(s):  
Blood Flow ◽  
Vascular Resistance ◽  
Broad Ligament ◽  
Flow Distribution ◽  
Uterine Blood Flow ◽  
Blood Flow Distribution ◽  
Blood Flows ◽  
17Β Estradiol ◽  
Vascular Beds ◽  
Reduced Rate

Prolonged 17β-estradiol (E2β) infusion decreases mean arterial pressure (MAP) and systemic vascular resistance (SVR) while increasing heart rate (HR) and cardiac output (CO). It is unclear, however, which systemic vascular beds show increases in perfusion. The purpose of this study was to determine which reproductive and nonreproductive vascular beds exhibit alterations in vascular resistance and blood flow during prolonged E2β infusion. Nonpregnant, ovariectomized sheep received either vehicle ( n = 6) or E2β (5 μg/kg iv bolus followed by 6 μg/kg over 24 h for 10 days; n= 9), and blood flow distribution was evaluated using radiolabeled microspheres at control and 120 min and 3, 6, 8, and 10 days of infusion. During E2β infusion MAP (87 ± 5 mmHg; mean ± SE) decreased 3–9% and HR (83 ± 5 beats/min) increased 4–31%. The combined baseline (control) perfusion to the uterus, broad ligament, oviducts, cervix, vagina, and mammary gland (reproductive blood flows) was 49 ± 9 ml/min; at 120 min, E2β increased flow ( P < 0.001) to 605 ± 74 ml/min (1,263%) and it remained elevated, but at a reduced rate, on day 3 (218 ± 44 ml/min; 399%), day 6 (144 ± 23; 217%), day 8(181 ± 19; 321%), and day 10 (204 ± 48; 454%), accounting for only 3–17% of the E2β-induced increase in CO. During this E2β treatment, there also were significant decreases in vascular resistances leading to increases ( P < 0.05) in blood flows to several nonreproductive (systemic) vascular beds including skin (32–113%), coronary (32–190%), skeletal muscle (25–133%), brain (21–292%), bladder (128–524%), spleen (87–180%), and pancreas (35–137%) vascular beds. Responses of these combined nonreproductive blood flows represent the major percentage (21–67%) of the E2β-induced increase in CO. Vehicle infusion was without effect. We conclude that prolonged E2β infusion increases reproductive and nonreproductive tissue blood flows. The latter appears to principally be responsible for the observed rise in CO and decrease in SVR.

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