Effects of prostaglandins E1, E2, and F2alpha on uterine blood flow in nonpregnant sheep

1978 ◽  
Vol 234 (5) ◽  
pp. H557-H561 ◽  
Author(s):  
R. Resnik ◽  
G. W. Brink
Keyword(s):  
Blood Flow ◽  
Base Line ◽  
Uterine Blood Flow ◽  
Electromagnetic Flow ◽  
Blood Flows ◽  
Vascular Bed ◽  
Uterine Contractile ◽  
Vasodilating Activity

The effects of prostaglandins E1, E2, and F2alpha (PGE1, PGE2, and PGE2alpha, respectively) on uterine blood flow were investigated in chronically catheterized, nonpregnant sheep equipped with electromagnetic flow probes. PGE1 was found to be a potent dilator of the uterine vascular bed and, at initial arterial concentratios of 1.5 micron (500 ng/ml), produced peak uterine blood flows similar to those achieved by a pulsed dose of 1 microgram 17beta-estradiol; PGE2 had less active vasodilating activity. Conversely, uterine intra-arterial PGF2alpha infusions, which produced initial concentrations of 0.1 micron (50 ng/ml), promptly reduced peak estrogen-stimulated uterine blood flow by 60%. All prostaglandin infusions stimulated increases in uterine contractile frequency and base-line tone. The findings demonstrate the sensitivity of the nonpregnant sheep uterine vasculature to prostaglandins.

Derecruitment of filtration surface area in paraquat-injured isolated dog lungs

1990 ◽  
Vol 68 (4) ◽  
pp. 1581-1589 ◽  
Author(s):  
T. Shibamoto ◽  
J. C. Parker ◽  
A. E. Taylor ◽  
M. I. Townsley
Keyword(s):  
Blood Flow ◽  
Surface Area ◽  
Vascular Resistance ◽  
High Flow ◽  
Base Line ◽  
Flow Rates ◽  
Blood Flows ◽  
Capillary Filtration Coefficient ◽  
Specific Index ◽  
Filtration Surface

The capillary filtration coefficient (Kf,c) is a sensitive and specific index of vascular permeability if surface area remains constant, but derecruitment might affect Kf,c in severely damaged lungs with high vascular resistance. We studied the effect of high and low blood flow rates on Kf,c in papaverine-pretreated blood-perfused isolated dog lungs perfused under zone 3 conditions with and without paraquat (PQ, 10(-2) M). Three Kf,cs were measured successively at hourly intervals for 5 h. These progressed sequentially from isogravimetric blood flow with low vascular pressure (I/L) to high flow with low vascular pressure (H/L) to high flow with high vascular pressure (H/H). The blood flows of H/L and H/H were greater than or equal to 1.5 times that of I/L. There were no significant changes in Kf,c in lungs without paraquat over a 50-fold range of blood flow rates. At 3 h after PQ, I/L-Kf,c was significantly increased and both isogravimetric capillary pressure and total protein reflection coefficient were decreased from base line. At 4 and 5 h, H/L-Kf,c was significantly greater than the corresponding I/L-Kf,c (1.01 +/- 0.22 vs. 0.69 +/- 0.09 and 1.26 +/- 0.19 vs. 0.79 +/- 0.10 ml.min-1.cmH2O-1.100 g-1, respectively) and isogravimetric blood flow decreased to 32.0 and 12.0% of base line, respectively. Pulmonary vascular resistance increased to 12 times base line at 5 h after PQ. We conclude that Kf,c is independent of blood flow in uninjured lungs. However, Kf,c measured at isogravimetric blood flow underestimated the degree of increase in Kf,c in severely damaged and edematous lungs because of a high vascular resistance and derecruitment of filtering surface area.

Transplacental clearance and blood flows of bovine gravid uterus at several stages of gestation

1987 ◽  
Vol 253 (5) ◽  
pp. R735-R739 ◽  
Author(s):  
L. P. Reynolds ◽  
C. L. Ferrell
Keyword(s):  
Blood Flow ◽  
Statistical Model ◽  
Deuterium Oxide ◽  
Gravid Uterus ◽  
Uterine Blood Flow ◽  
Blood Flows ◽  
Bovine Placenta ◽  
Umbilical Blood ◽  
Placental Blood ◽  
Umbilical Blood Flow

Rates of uterine and umbilical blood flows and transplacental clearance of deuterium oxide (D2O) were determined for cows on 137 +/- 1.0 (SE, n = 9), 180 +/- 0.5 (n = 8), 226 +/- 0.4 (n = 9), and 250 +/- 1.8 (n = 5) days of gestation. From days 137 to 250, rates increased 4.5-fold for uterine blood flow, 21-fold for umbilical blood flow, and 14-fold for clearance of D2O. Changes in rates of umbilical blood flow and D2O clearance paralleled increased rates of fetal growth and metabolism, which have previously been reported to occur during the last half of gestation. The regressions of D2O clearance on uterine and umbilical blood flows were significant (P less than 0.01) and explained 94-99% of the variation in placental clearance of D2O. Because the rate of D2O clearance was always less than that of uterine and umbilical blood flows, and because a relatively simple statistical model explained most of the variation in clearance, it was suggested that a concurrent or countercurrent arrangement of maternal and fetal placental microvasculatures is not adequate to explain clearance of highly diffusable substances across the bovine placenta. In addition, a placental exchange diagram of the data showed the existence of severe uneven distribution of maternal and fetal placental blood flows and/or significant shunting of maternal and fetal placental flows away from areas of exchange. Taken together, these data indicate that the placenta of the cow, like those of the sheep and goat, represents a relatively inefficient system of transplacental exchange.

Effect of prostaglandin E2 on ovine maternal placental blood flow

1976 ◽  
Vol 231 (3) ◽  
pp. 754-759 ◽  
Author(s):  
JH Rankin ◽  
TM Phernetton
Keyword(s):  
Blood Flow ◽  
Renal Blood Flow ◽  
Placental Transfer ◽  
Venous Catheter ◽  
Uterine Blood Flow ◽  
Blood Flows ◽  
Pregnant Sheep ◽  
Maternal Brain ◽  
Regional Blood Flows ◽  
Near Term

The effect of PGE2 on regional blood flows in the chronically catheterized near-term pregnant sheep was investigated using radioactive microspheres. The injection of 20 mug PGE2 per kilogram into the left ventricle of eight sheep resulted in no change in maternal brain and noncotyledonary uterine flow. The renal blood flow increased from 692 to 892 ml/min (P less than 0.004). The uterine blood flow decreased from 673 to 317 ml/min (P less than 0.001). The trium was bypassed by injecting 7 mug PGE2 per kilogram of sheep into a fetal venous catheter and permitting it to reach the placental vasculature after placental transfer. Eleven sets of observations were made in eight animals. We observed no change in the intrauterine pressure, maternal brain flow, and noncotyledonary uterine blood flow secondary to this procedure. The maternal renal blood flow changed from 592 to 669 ml/min (P less than 0.007). The uterine blood flow increased from 762 to 853 ml/min (P less than 0.02). The uterine vascular resistance decreased from 0.124 to 0.115 mmHg x min/ml (P less than 0.04). It was concluded that 1) PGE3 crosses the placenta quite readily, and 2) PGE3 causes dilatation of the maternal placental vascular bed.

Relationship between uterine blood flow and endometrial and subendometrial blood flows during stimulated and natural cycles

2006 ◽  
Vol 85 (3) ◽  
pp. 721-727 ◽  
Author(s):  
Ernest H.Y. Ng ◽  
Carina C.W. Chan ◽  
Oi S. Tang ◽  
William S.B. Yeung ◽  
Pak C. Ho
Keyword(s):  
Blood Flow ◽  
Uterine Blood Flow ◽  
Blood Flows ◽  
Natural Cycles

Effects of Dopamine and Other Catecholamines on the Splanchnic Circulation

1972 ◽  
Vol 50 (6) ◽  
pp. 594-602 ◽  
Author(s):  
Linda L. Shanbour ◽  
Don Parker
Keyword(s):  
Blood Flow ◽  
Hepatic Artery ◽  
Mesenteric Artery ◽  
Splanchnic Circulation ◽  
Blood Flows ◽  
Vascular Bed ◽  
Competitive Action ◽  
Responses To Dopamine ◽  
Mesenteric Vascular Bed ◽  
Dose Levels

Studies were conducted to evaluate the effects of dopamine (3, 4-dihydroxyphenylethylamine) and other catecholamines on the mesenteric vascular bed in dogs. Mesenteric and hepatic artery blood flows were measured with electromagnetic blood flow transducers. Catecholamines were infused intra-arterially into a branch-of the mesenteric artery. Dopamine consistently decreased mesenteric and hepatic artery blood flows at all dose levels studied (5–100 mg/kg). Phenoxybenzamine (12.5 mg/kg) blocked the effects of norepinephrine (0.05–1.0 μg/kg) and reversed the responses to dopamine in the mesenteric bed to those of pure vasodilation (no transient constriction was observed) but failed to abolish the constrictor action of dopamine on the hepatic artery. Propranolol or haloperidol, when administered with the phenoxybenzamine, did not attenuate the mesenteric responses to dopamine. Haloperidol prevented the hepatic artery vasoconstriction produced by dopamine but did not alter isoproterenol-induced hepatic artery vasodilation. No competitive action was observed between dopamine and norepinephrine or isoproterenol. These results suggest that (1) dopamine produces selective vasodilation of the mesenteric bed which is not blocked by haloperidol, and (2) dopamine has a unique action on the hepatic vascular bed which is blocked by haloperidol.

Regional blood flow and vascular resistance in response to oxytocin in the pregnant sheep and dog

1961 ◽  
Vol 16 (6) ◽  
pp. 1087-1092 ◽  
Author(s):  
N. S. Assali ◽  
L. Holm ◽  
H. Parker
Keyword(s):  
Blood Flow ◽  
Vascular Resistance ◽  
Regional Blood Flow ◽  
Uterine Blood Flow ◽  
Pregnant Uterus ◽  
Blood Flows ◽  
Uterine Contractions ◽  
Intravenous Drip ◽  
Pregnant Sheep ◽  
Regional Vascular Resistance

The effects of oxytocin on regional blood flow and regional vascular resistance were investigated in a group of pregnant ewes and bitches not in labor and in another group in early labor. Single injections or intravenous drip infusion did not change significantly arterial pressure, cardiac output, electrocardiogram, and renal, iliac, femoral, and carotid blood flows in any of the animals studied. The effects on the pregnant uterus were negligible before the onset of spontaneous labor. Only when the animal was in labor did oxytocin produce an increase in uterine contractions accompanied by a significant decrease in uterine blood flow. The data indicate that in the pregnant sheep and dog the circulatory action of oxytocin is limited to the pregnant uterus in labor and that the decrease in blood flow is probably due to an increase in intramural vascular resistance caused by the contracting myometrium around the uterine arterioles. Submitted on May 5, 1961

Effect of restriction of placental growth on umbilical and uterine blood flows

1986 ◽  
Vol 250 (3) ◽  
pp. R427-R434 ◽  
Author(s):  
J. A. Owens ◽  
J. Falconer ◽  
J. S. Robinson
Keyword(s):  
Blood Flow ◽  
Subsequent Pregnancy ◽  
Placental Weight ◽  
Fetal Weight ◽  
Uterine Blood Flow ◽  
Antipyrine Clearance ◽  
Blood Flows ◽  
Umbilical Blood ◽  
Umbilical Blood Flow ◽  
Vascular Catheters

Endometrial caruncles were excised from sheep (caruncle sheep) before pregnancy. The effect of this on umbilical and uterine blood flows in a subsequent pregnancy was examined. Thirteen caruncle and twelve control sheep with indwelling vascular catheters were studied at 121 and 130 days pregnancy. In caruncle sheep, fetal, placental, and total uterine content weights were significantly lower than in control sheep. Six caruncle sheep carried normal-sized fetuses (weight within +/- 2 SD of mean weight for control fetuses) and seven carried small fetuses (weight greater than +/- 2 SD below mean weight for control fetuses). Mean weights of placentas in these groups were 0.290 +/- 0.067 and 0.156 +/- 0.069 kg, respectively, compared with 0.459 +/- 0.157 kg in control sheep. In small caruncle fetuses, umbilical and uterine blood flows and placental antipyrine clearance were significantly lower than in controls at 121 and 130 days gestation. Only umbilical blood flow was reduced in normal-sized caruncle fetuses. Umbilical blood flow and placental antipyrine clearance increased with gestational age in control sheep but not in sheep with normal-sized or small caruncle fetuses. In all sheep, umbilical and uterine blood flows and antipyrine clearance correlated with placental weight. Umbilical blood flow per kilogram of placenta but not uterine blood flow per kilogram of placenta correlated inversely with placental weight. Fetal weight at 130 days generally correlated with placental weight, umbilical and uterine blood flows, and antipyrine clearance in a curvilinear fashion such that fetal weight was not greatly restricted until these variables were less than or equal to 65% of control values.

Metabolism of the gravid uterus, foetus and utero-placenta at several stages of gestation in cows

1986 ◽  
Vol 106 (3) ◽  
pp. 437-444 ◽  
Author(s):  
L. P. Reynolds ◽  
C. L. Ferrell ◽  
Debra A. Robertson ◽  
S. P. Ford
Keyword(s):  
Blood Flow ◽  
Deuterium Oxide ◽  
N Uptake ◽  
Gravid Uterus ◽  
Uterine Blood Flow ◽  
Indwelling Catheters ◽  
Blood Flows ◽  
Umbilical Blood ◽  
Rate Of Increase ◽  
Umbilical Blood Flow

SummaryTo quantify changes in rates of metabolism and nutrient uptake of gravid uteiine, foetal and utero-placental tissues throughout gestation, mature Hereford cows received surgery at 132 ± 0·6 (n = 12), 176 ± 0·5 (n = 8), 220 ±0·4 (n = 11) and 245 ±1·5 (n = 7) days after mating. Indwelling catheters were implanted into a uterine artery and vein of all cows. Foetal catheters also were implanted into an umbilical vein and foetal femoral artery and vein (days 176 and 220) or into a placental artery and two placental veins (days 132 and 245). Approximately 5 days after surgery, deuterium oxide was infused into a foetal femoral venous or placental venous catheter during a 3 h period to quantify uterine and umbilical blood flows by steady-state diffusion methods. Oxygen, glucose, lactate and α-amino acid nitrogen concentrations were determined for uterine and foetal blood samples collected during this procedure.Uterine blood flow increased 4·5-fold (2·92–13·181/min) and umbilical blood flow increased 21-fold (0·28–5·861–min) during the interval of gestation studied. The relative rate of increase of umbilical blood flow was about twice as great as that of uterine blood flow. Uterine arterial and umbilical venous concentrations as well as uterine arterial-venous and umbilical venous-arterial concentration differences in metabolites changed little with stage of gestation. However, because rates of blood flow increased, uptakes of O2, glucose and α-amino N by the gravid uterus and foetus increased as gestation advanced. The proportion of gravid uterine uptakes utilized by the foetus increased from day 137 to 226 for O2 (24–58%) and from day 137 to 180 for glucose (4–19%), then remained relatively constant. The proportion of gravid uterine α-amino N uptake utilized by the foetus remained relatively constant and averaged 60%. A net secretion of lactate from the utero-placenta to the uterine and foetal circulations was observed and increased as gestation advanced. These data indicate that increased rates of uptake or secretion of metabolites by tissues of the gravid uterus can be explained primarily by increased rates of uterine and umbilical blood flows.

Systemic and regional hemodynamic effects of endogenous vasopressin stimulation in rats

1982 ◽  
Vol 243 (4) ◽  
pp. H560-H565
Author(s):  
F. Charocopos ◽  
P. Hatzinikolaou ◽  
W. G. North ◽  
H. Gavras
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Vascular Resistance ◽  
Peripheral Resistance ◽  
Base Line ◽  
Blood Flows ◽  
Fluid Load ◽  
Regional Blood Flows ◽  
Blood Pressures ◽  
Specific Antagonist

We investigated the systemic and regional hemodynamic alterations induced in normotensive anephric rats by stimulation of endogenous vasopressin with an acute sodium and fluid load and following vasopressin inhibition with a specific antagonist of its vasoconstricting action. Blood pressure and total peripheral resistance were significantly higher and cardiac output was lower in rats with stimulated vasopressin, and all were reversed to near control levels in rats receiving the vasopressin inhibitor. Regional blood flows were diminished in most organs and local vascular resistance was elevated compared with control animals, but the magnitude of change varied widely. In fact, heart blood flow did not decrease significantly and brain blood flow actually increased indicating small or no change in vascular resistance of these organs. Moreover, fractional distribution of the diminished cardiac output to these organs was significantly higher, so that blood flow to vital organs was maintained at the expense of blood flow to other tissues. In rats that received the vasopressin antagonist after the saline infusion, regional blood flows were similar to those of control animals. Blood pressures at the base line and after hypertonic NaCl infusion correlated closely with the corresponding plasma levels of control and stimulated vasopressin.

Uterine and nonuterine vascular responses to angiotensin II in ovine pregnancy

1989 ◽  
Vol 257 (1) ◽  
pp. H17-H24 ◽  
Author(s):  
C. R. Rosenfeld ◽  
R. P. Naden
Keyword(s):  
Blood Flow ◽  
Angiotensin Ii ◽  
Vascular Resistance ◽  
Ang Ii ◽  
Uterine Blood Flow ◽  
Blood Flows ◽  
Pregnant Sheep ◽  
Regional Blood Flows ◽  
Dose Dependent ◽  
Systemic Responses

The uteroplacental vasculature is more refractory to angiotensin II (ANG II) than the systemic vasculature as a whole. To ascertain the differences in responses between reproductive and nonreproductive tissues that account for this, we infused ANG II (0.573, 5.73, and 11.5 micrograms/min) in pregnant sheep (137 +/- 5 days of gestation) and monitored arterial pressure (MAP), heart rate, and uterine blood flow (UBF); cardiac output and regional blood flows were measured with radiolabeled microspheres. Dose-dependent changes in MAP, UBF, and systemic (SVR) and uterine (UVR) vascular resistance occurred (P less than 0.05); systemic responses exceeded uterine (P less than 0.05), except with 11.5 micrograms/min, when % delta UVR = % delta SVR, % delta UVR greater than % delta MAP, and UBF fell 29%. Although a dose-dependent rise in placental resistance occurred, blood flow was unaffected except at 11.5 micrograms ANG II/min, falling 16.8 +/- 3.5% (P = 0.059). In contrast, endometrial perfusion decreased 68 +/- 4.2 and 81 +/- 1.8% (P less than 0.01) with 5.73 and 11.5 micrograms ANG II/min, respectively. Myometrial responses were intermediate, thus placental flow increased from 75 to greater than 90% of total UBF. Adipose, renal, and adrenal glands were extremely sensitive to ANG II, with blood flows decreasing maximally at 0.573 micrograms/min (P less than 0.05). Maximum adipose vascular resistance occurred at 0.573 micrograms/min, greater than 400% (P less than 0.001), exceeding responses in all tissues (P less than 0.05). The placenta is less responsive to ANG II than other uterine and most nonreproductive tissues, resulting in preferential maintenance of uteroplacental perfusion and protecting the fetus from the effects of this vasoconstrictor.

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