The selective closure of feline carotid arteriovenous anastomoses (AVAs) by GR43175

The haemodynamic effects of the selective 5-HT1-like agonist GR43175 have been compared with that of ergotamine in anaesthetized cats. Both GR43175 (30–1000 μg/kg intravenously) and ergotamine (0.3–30 μg/kg intravenously) caused a dose-dependent reduction in the proportion of cardiac output passing through arteriovenous anastomoses (AVAs). However, unlike GR43175, the effect of ergotamine (30 μg/kg intravenously) was associated with marked increases in diastolic blood pressure and total peripheral resistance. In further studies, the effect of GR43175 on the distribution of blood flow within the carotid bed has been examined. GR43175 caused a reduction in total carotid arterial blood flow which was entirely due to a reduction in flow through carotid AVAs. These results demonstrate that GR43175, unlike ergotamine, has a highly selective vasoconstrictor action on AVAs within the cranial circulation of anaesthetized cats. Such a mechanism may be important in its antimigraine activity.

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Regulation of arterial blood pressure in the common green iguana

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1975.228.2.386 ◽

1975 ◽

Vol 228 (2) ◽

pp. 386-391 ◽

Cited By ~ 17

Author(s):

LA Hohnke

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Blood Flow ◽

Arterial Pressure ◽

Arterial Blood Pressure ◽

Venous Pressure ◽

Arterial Blood Flow ◽

Arterial Blood ◽

Head Up Tilt ◽

Carotid Arterial

Arterial blood pressure (ABP) responses to graded hemorrhage and passive head-up tilt were studied in restrained, anesthetized, and unanesthetized iguanas. The ABP fell slowly in response to hemorrhage up to a critical deficit of 35 plus or minus 19% of the estimated blood volume; the rate of ABP fall then increased nearly 40-fold to continued hemorrhage. Increased heart rate and decreased femoral arterial blood flow accompanied progressive hemorrhage. Propranolol (2-3 mug/kg) did not appreciably alter arterial pressure-hemorrhage curves but hemorrhage-induced increases in heart rate were diminished nearly 50%. Atropine had little effect on either the blood pressure or heart rate changes induced by hemorrhage. During passive tilts of 0-90 degrees carotid arterial pressure fell 33% before returning to control levels (2 min). Heart rate increased and femoral arterial blood flow and central venous pressure fell in response to head-up tilts. It is concluded that hemorrhage and passive head-up tilting can induce reflex cardiovascular changes that assist ABP regulation in iguanas.

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Increased vascular resistance in paralyzed legs after spinal cord injury is reversible by training

Journal of Applied Physiology ◽

10.1152/japplphysiol.00897.2001 ◽

2002 ◽

Vol 93 (6) ◽

pp. 1966-1972 ◽

Cited By ~ 64

Author(s):

Maria T. E. Hopman ◽

Jan T. Groothuis ◽

Marcel Flendrie ◽

Karin H. L. Gerrits ◽

Sibrand Houtman

Keyword(s):

Blood Pressure ◽

Spinal Cord ◽

Spinal Cord Injury ◽

Blood Flow ◽

Mean Arterial Pressure ◽

Arterial Pressure ◽

Vascular Resistance ◽

Arterial Blood Flow ◽

Arterial Blood ◽

Cord Injury

The purpose of the present study was to determine the effect of a spinal cord injury (SCI) on resting vascular resistance in paralyzed legs in humans. To accomplish this goal, we measured blood pressure and resting flow above and below the lesion (by using venous occlusion plethysmography) in 11 patients with SCI and in 10 healthy controls (C). Relative vascular resistance was calculated as mean arterial pressure in millimeters of mercury divided by the arterial blood flow in milliliters per minute per 100 milliliters of tissue. Arterial blood flow in the sympathetically deprived and paralyzed legs of SCI was significantly lower than leg blood flow in C. Because mean arterial pressure showed no differences between both groups, leg vascular resistance in SCI was significantly higher than in C. Within the SCI group, arterial blood flow was significantly higher and vascular resistance significantly lower in the arms than in the legs. To distinguish between the effect of loss of central neural control vs. deconditioning, a group of nine SCI patients was trained for 6 wk and showed a 30% increase in leg blood flow with unchanged blood pressure levels, indicating a marked reduction in vascular resistance. In conclusion, vascular resistance is increased in the paralyzed legs of individuals with SCI and is reversible by training.

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Carotid Arterial Blood Flow in the Ovine Fetus as a Continuous Measure of Cerebral Blood Flow

Journal of the Society for Gynecologic Investigation ◽

10.1177/107155769600300204 ◽

1996 ◽

Vol 3 (2) ◽

pp. 60-65 ◽

Cited By ~ 13

Author(s):

Robert Gratton ◽

Lesley Carmichael ◽

Jacobus Homan ◽

Bryan Richardson

Keyword(s):

Blood Flow ◽

Cerebral Blood Flow ◽

Arterial Blood Flow ◽

Continuous Measure ◽

Arterial Blood ◽

Ovine Fetus ◽

Carotid Arterial

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Vasodilation of cat cerebral arterioles by prostaglandins D2, E2, G2, and I2

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1979.237.3.h381 ◽

1979 ◽

Vol 237 (3) ◽

pp. H381-H385 ◽

Cited By ~ 4

Author(s):

E. F. Ellis ◽

E. P. Wei ◽

H. A. Kontos

Keyword(s):

Blood Pressure ◽

Blood Flow ◽

Cerebral Blood Flow ◽

Arterial Blood Pressure ◽

Standard Error ◽

Arterial Blood ◽

Cerebral Arterioles ◽

The Mean ◽

Dose Dependent ◽

The Brain

To determine the possible role that endogenously produced prostaglandins may play in the regulation of cerebral blood flow, the responses of cerebral precapillary vessels to prostaglandins (PG) D2, E2, G2, and I2 (8.1 X 10(-8) to 2.7 X 10(-5) M) were studied in cats equipped with cranial windows for direct observation of the microvasculature. Local application of PGs induced a dose-dependent dilation of large (greater than or equal to 100 microns) and small (less than 100 microns) arterioles with no effect on arterial blood pressure. The relative vasodilator potency was PGG2 greater than PGE2 greater than PGI2 greater than PGD2. With all PGs, except D2, the percent dilation of small arterioles was greater than the dilation of large arterioles. After application of prostaglandins in a concentration of 2.7 X 10(-5) M, the mean +/- standard error of the percent dilation of large and small arterioles was, respectively, 47.6 +/- 2.7 and 65.3 +/- 6.1 for G2, 34.1 +/- 2.0, and 53.6 +/- 5.5 for E2, 25.4 +/- 1.8, and 40.2 +/- 4.6 for I2, and 20.3 +/- 2.5 and 11.0 +/- 2.2 for D2. Because brain arterioles are strongly responsive to prostaglandins and the brain can synthesize prostaglandins from its large endogenous pool of prostaglandin precursor, prostaglandins may be important mediators of changes in cerebral blood flow under normal and abnormal conditions.

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EFFECT OF DIFFERENT OCCLUSION PRESSURE ON PECULIARITIES OF MUSCLE BLOOD FLOW

Baltic Journal of Sport and Health Sciences ◽

10.33607/bjshs.v1i108.3 ◽

2018 ◽

Vol 1 (108) ◽

pp. 2-8

Author(s):

Kęstutis Bunevičius ◽

Albinas Grunovas ◽

Jonas Poderys

Keyword(s):

Blood Pressure ◽

Blood Flow ◽

Arterial Blood Pressure ◽

Arterial Blood Flow ◽

Control Group ◽

Reactive Hyperaemia ◽

Occlusion Pressure ◽

Arterial Blood ◽

Flow Intensity ◽

Blood Flow Intensity

Background. Occlusion pressure intensity influences the blood flow intensity. Immediately after the cuff pressure is released, reactive hyperaemia occurs. Increased blood flow and nutritive delivery are critical for an anabolic stimulus, such as insulin. The aim of study was to find which occlusion pressure was optimal to increase the highest level of post occlusion reactive hyperaemia. Methods. Participants were randomly assigned into one of the four conditions (n = 12 per group): control group without blood flow restriction, experimental groups with 120; 200 or 300 mmHg occlusion pressure. We used venous occlusion plethysmography and arterial blood pressure measurements. Results. After the onset of 120 and 200 mm Hg pressure occlusion, the blood flow intensity significantly decreased. Occlusion induced hyperaemia increased arterial blood flow intensity 134 ± 11.2% (p < .05) in the group with 120 mmHg, in the group with 200 mmHg it increased 267 ± 10.5% (p < .05), in the group with 300 mmHg it increased 233 ± 10.9% (p < .05). Applied 300 mmHg occlusion from the 12 minute diastolic and systolic arterial blood pressure decreased statistically significantly. Conclusions. Occlusion manoeuvre impacted the vascular vasodilatation, but the peak blood flow registered after occlusion did not relate to applied occlusion pressure. The pressure of 200 mmHg is optimal to impact the high level of vasodilatation. Longer than 12 min 300 mmHg could not be recommended due to the steep decrease of systolic and diastolic blood pressures.

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Abstract P308: Rgs2 Promotes Uterine Blood Flow During Pregnancy

Hypertension ◽

10.1161/hyp.70.suppl_1.p308 ◽

2017 ◽

Vol 70 (suppl_1) ◽

Author(s):

Jennifer N Koch ◽

Elizabeth A Owens ◽

Shelby Dahlen ◽

Jie Li ◽

Patrick Osei Owusu

Keyword(s):

Gene Expression ◽

Blood Pressure ◽

Blood Flow ◽

G Protein ◽

Arterial Blood Flow ◽

G Protein Signaling ◽

Protein Signaling ◽

Uterine Blood Flow ◽

Placental Perfusion ◽

Arterial Blood

Regulators of G protein signaling (RGS) proteins are crucial in mediating vascular smooth muscle contraction via the regulation of heterotrimeric G proteins, affecting blood pressure and arterial blood flow. Previous studies by others and us showed that RGS2 deficiency augments vascular tone and impairs uterine blood flow (UBF) in non-pregnant mice, and that an Rgs2 loss-of-function mutation is linked to preeclampsia in humans; however, the mechanisms are unclear. Here, we tested the hypothesis that increased RGS2 expression and/or function facilitates placental perfusion by promoting vasodilation and UBF. We determined gene expression throughout pregnancy and post-partum period by real-time qPCR, while uterine blood flow and blood pressure were examined by ultrasound and carotid artery catheterization, respectively, under anesthesia. RGS2 expression decreased markedly by pregnancy day 10 (0.049 ± 0.013 vs. 0.023 ± 0.017) but returned to non-pregnancy level by day 15 (0.049 ± 0.013 vs. 0.041 ± 0.008,) in wild type mice. The pattern of changes in impedance to UBF mimicked gene expression profile in WT mice; in contrast, impedance remained elevated in Rgs2-/- mice at pregnancy day 15 (RI; WT: 0.516 ± 0.027, vs. RGS2-/-: 0.714 ± 0.020). Systemic blood pressure was similar between WT and Rgst2-/- mice at all stages of pregnancy. The results together indicate that RGS2 promotes uterine perfusion during pregnancy independently of its blood pressure effects. These findings are clinically relevant as selective targeting of G protein signaling could improve utero-placental hypoperfusion during pregnancy and prevent the development of pregnancy complications such as preeclampsia.

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Circulatory effects of acute or chronic endotoxemia in rats

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y81-034 ◽

1981 ◽

Vol 59 (2) ◽

pp. 204-208 ◽

Cited By ~ 4

Author(s):

R. Keeler ◽

Anamaria Barrientos ◽

K. Lee

Keyword(s):

Escherichia Coli ◽

Blood Pressure ◽

Blood Flow ◽

Cardiac Output ◽

Gastrointestinal Tract ◽

Peripheral Resistance ◽

Circulatory Effects ◽

Arterial Blood ◽

Flow Changes ◽

Fractional Distribution

A study was made of the effects of acute (4 h) or chronic (4 days) infusion of Escherichia coli endotoxin on cardiovascular function in rats. Rats with acute endotoxemia had a reduced cardiac output but maintained their arterial blood pressure. Fractional distribution of the cardiac output was increased to the liver and reduced to the gastrointestinal tract and skin. No changes in fractional distribution to the kidneys, lungs, or heart were observed although absolute blood flow to these areas was reduced.Rats with chronic endotoxemia had a reduced cardiac output and hypotension with no change in peripheral resistance. Other changes resembled those seen in acute endotoxemia apart from a low renal fraction of the cardiac output. Calculation and interpretation of blood flow changes in these animals was difficult because of a large fall in hematocrit and changes in organ weight.

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