Postprandial hemodynamics in the conscious rat

1986 ◽  
Vol 251 (1) ◽  
pp. G117-G123 ◽  
Author(s):  
L. Anzueto Hernandez ◽  
P. R. Kvietys ◽  
D. N. Granger
Keyword(s):  
Blood Flow ◽  
Mixed Meal ◽  
Conscious Rat ◽  
Conscious Rats ◽  
Blood Flows ◽  
Radioactive Microsphere ◽  
Radioactive Microsphere Technique ◽  
Bowel Segments ◽  
Conscious Animals ◽  
Hyperemic Response

The postprandial intestinal hyperemia was studied in conscious and anesthetized rats using the radioactive microsphere technique. Carbohydrate, protein, lipid, and mixed meals, and the vehicle (Tyrode's solution), were placed in the stomach via a gastrostomy tube. In conscious rats, blood flow increased by 40-80% in the duodenum and jejunum 1 h after either a carbohydrate, lipid, protein, or mixed meal. Tyrode's solution produced a comparable hyperemia. Blood flow in the distal bowel segments (ileum, cecum, and colon) was significantly increased only by Tyrode'ds solution and the carbohydrate meal. The proximal intestinal hyperemia produced by the mixed meal in conscious animals was significantly attenuated by vagotomy yet unaltered by atropine pretreatment. In contrast to the results obtained from conscious rats, the mixed meal did not significantly alter intestinal blood flow in anesthetized animals. The results of this study indicate that the postprandial intestinal hyperemia is much greater in conscious than anesthetized animals. This difference may result from the higher resting blood flows in the latter group. The hyperemic response in conscious animals may be mediated by the vagus nerve.

Systemic and regional haemodynamic effects of a synthetic atrial natriuretic peptide in conscious rats

1986 ◽  
Vol 71 (3) ◽  
pp. 323-325 ◽  
Author(s):  
Carlos Caramelo ◽  
Arturo Fernandez-Cruz ◽  
Luis M. Villamediana ◽  
Elias Sanz ◽  
Diego Rodriguez-Puyol ◽  
...  
Keyword(s):  
Blood Flow ◽  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Portal Blood Flow ◽  
Haemodynamic Effects ◽  
Conscious Rats ◽  
Blood Flows ◽  
Radioactive Microsphere ◽  
Radioactive Microsphere Technique ◽  
Atrial Natriuretic

1. The effect of the intravenous injection of synthetic atrial natriuretic peptide (ANP, 2 μg) on systemic haemodynamics and blood flow to several organs has been studied in conscious rats by the radioactive microsphere technique. 2. ANP induced a 540% increase in sodium excretion and a 310% increase in urine flow. Mean arterial pressure decreased by 21 mmHg and the peripheral resistances decreased by 26%, without significant changes in cardiac output. 3. Renal blood flow increased by 37.7% and small intestine and portal blood flow increased by 39% and by 28% respectively. No other alterations in organ blood flows were observed. 4. From these data it can be concluded that atrial natriuretic peptide shows acute vascular relaxant properties, which seem to be specific for renal and mesenteric territories.

Total and regional blood flows in vascularized skeletal muscle grafts in rabbits

1988 ◽  
Vol 255 (5) ◽  
pp. H1043-H1049
Author(s):  
H. W. Burton ◽  
T. R. Stevenson ◽  
R. C. Dysko ◽  
K. P. Gallagher ◽  
J. A. Faulkner
Keyword(s):  
Blood Flow ◽  
Skeletal Muscles ◽  
Rectus Femoris ◽  
Specific Force ◽  
Total Blood ◽  
Blood Flows ◽  
Vascular Bed ◽  
Radioactive Microsphere ◽  
Radioactive Microsphere Technique ◽  
Regional Blood Flows

The transplantation of whole skeletal muscles is a common clinical procedure. Although atypical blood flows have been reported in small free muscle grafts, the blood flow of large neurovascular-intact (NVI) and neurovascular-anastomosed (NVA) grafts have not been measured. Because the maximum specific force (N/cm2) of NVI and NVA grafts is 65% that of control muscles, we hypothesized that total and regional blood flows (ml.min-1.100g-1) of NVI and NVA grafts at rest and during twitch contractions are significantly lower than lower flows of control muscles. In rabbits, blood flows of control rectus femoris (RFM) muscles and NVI and NVA grafts of RFM muscles were measured by the radioactive-microsphere technique. In control muscles, blood flow increased linearly from 6.8 +/- 1 ml.min-1.100 g-1 at rest to 64.4 +/- 7 ml.min-1. 100 g-1 at a stimulation frequency of 3 Hz with no further increase at 4 Hz. Total blood flows in grafts were not different from the control RFM muscle values, except for a higher resting flow in NVA grafts and a lower flow at 3 Hz in NVI grafts. Minor variations in regional flows were observed. We conclude that the operative procedures of grafting and repair of blood vessels affect the vascular bed of muscles minimally, and the deficits observed in grafts do not arise from inadequate perfusion.

Regional blood flows measured in conscious rats by combined Fick and microsphere methods

1978 ◽  
Vol 235 (3) ◽  
pp. H357-H360 ◽  
Author(s):  
M. Tsuchiya ◽  
R. A. Ferrone ◽  
G. M. Walsh ◽  
E. D. Frohlich
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Regional Blood Flow ◽  
Reference Sample ◽  
Conscious Rat ◽  
Flow Measurements ◽  
Conscious Rats ◽  
Radioactive Microsphere ◽  
Regional Blood Flows ◽  
Blood Flow Measurements

Regional blood flow measurements made by the radioactive microsphere technique were studied in conscious rats. A femoral arterial reference sample blood flow was measured directly, and at the same time indirectly by the combined use of direct Fick cardiac output and microsphere techniques. A significant correlation (r = .81, P less than .01) was obtained between direct and indirect blood flow values when 200--400 microspheres were trapped in the reference sample. When 100--200 microspheres were trapped, regional blood flow was 32% below true flow (P less than .01); and cardiac output, calculated by the reference sample method, was 57% greater than Fick cardiac output (P less than .01). When three consecutive Fick determinations and microsphere injections (20,000 per injection, 15 micrometer diam) were made in conscious rats, significant correlations were obtained among the first, second, and third regional blood flow measurements (r = .95, P less than .01). The results have demonstrated that cardiac output and reference blood flow can be measured with accuracy and precision in the conscious rat by the radioactive microsphere procedure.

Blood flow in normal and denervated muscle during exercise in conscious rats

1988 ◽  
Vol 255 (6) ◽  
pp. H1509-H1515 ◽  
Author(s):  
M. D. Delp ◽  
R. B. Armstrong
Keyword(s):  
Blood Flow ◽  
Muscular Activity ◽  
Sprague Dawley ◽  
Blood Flows ◽  
Sprague Dawley Rats ◽  
Mechanical Factors ◽  
Denervated Muscles ◽  
Gastrocnemius Muscles ◽  
Low Intensity Exercise ◽  
Hyperemic Response

The purpose of this study was to test the hypothesis that extrinsic mechanical factors, i.e., the dynamic shortening and lengthening imposed on a muscle during limb movements and the rhythmic compressions as surrounding muscles contract and relax, contribute to the initial muscle hyperemia during locomotion in conscious male Sprague-Dawley rats. Soleus and lateral head of gastrocnemius muscles were surgically denervated in one hindlimb several hours before exercise to remove 1) local metabolic vasodilator effects, 2) vasoconstrictor or vasodilatory influences mediated through sympathetic postganglionic fibers, and 3) intrinsic mechanical pumping. Blood flow was measured with radioactive microspheres during preexercise and at 30 s and 5 min of exercise in rats walking at 15 m/min or a motor-driven treadmill. Glycogen concentrations were also measured as an indicator of muscular activity to verify the denervation. Blood flows to control muscles in the normal limb were similar to previously reported values during preexercise and exercise. Denervation, however, decreased preexercise blood flow (69–88%) to muscle composed predominantly of oxidative fibers and increased flow (53%) to muscle composed predominantly of glycolytic fibers. During exercise, blood flow to denervated muscles either remained unchanged or decreased. These data suggest that extrinsic mechanical factors do not significantly contribute to the initial hyperemic response at the onset of low-intensity exercise in normal muscle.

Influence of a mixed meal on splanchnic and interscapular energy expenditure in humans

1991 ◽  
Vol 260 (2) ◽  
pp. E232-E237 ◽  
Author(s):  
T. Brundin ◽  
J. Wahren
Keyword(s):  
Blood Flow ◽  
Venous Blood ◽  
Venous Blood Flow ◽  
O2 Uptake ◽  
Mixed Meal ◽  
Interscapular Brown Adipose Tissue ◽  
Blood Flows ◽  
Blood Temperature ◽  
Brown Adipose ◽  
Regional Blood Flows

Pulmonary, splanchnic, and interscapular O2 uptake was studied in 14 male volunteers before and for 90 min after a mixed meal. Thermistor catheters were inserted into a hepatic vein, the azygous vein, the pulmonary artery, and the aorta. Systemic and regional blood flows were determined during indirect calorimetry measurements and recordings of blood temperature. After the meal, pulmonary O2 uptake rose by 33-49 ml/min and splanchnic O2 uptake increased by 16-25 ml/min. In the azygous region O2 uptake did not increase significantly. Cardiac output increased after the meal by 1.1-1.5 l/min and splanchnic blood flow rose by 0.4-0.9 l/min. Azygous venous blood flow increased from 130 +/- 19 ml/min to 163 +/- 23 ml/min. In relation to splanchnic O2 uptake, the blood-drained splanchnic heat was low, 11 +/- 1 J/ml, and decreased to 7 +/- 1 J/ml after the meal. We conclude that after a mixed meal approximately one-half of the rise in O2 uptake occurs in the splanchnic organs; azygous-drained tissues, including possible interscapular brown adipose tissue, contribute minimally. The amount of heat drained with blood from the splanchnic region was low in relation to the splanchnic O2 uptake, indicating that splanchnic heat may be dissipated by routes other than the perfusing blood.

Blood flow responses to small bowel resection

1986 ◽  
Vol 251 (6) ◽  
pp. G815-G822 ◽  
Author(s):  
M. G. Ulrich-Baker ◽  
M. E. Hollwarth ◽  
P. R. Kvietys ◽  
D. N. Granger
Keyword(s):  
Blood Flow ◽  
Small Bowel ◽  
Dna Synthesis ◽  
Dna Content ◽  
Bowel Resection ◽  
Small Bowel Resection ◽  
Proximal Jejunum ◽  
Blood Flows ◽  
Gastrointestinal Blood Flow ◽  
Bowel Segments

The objective of this study was to determine whether the gastrointestinal blood flow response to small bowel resection is related to the compensatory hyperplasia resulting from resection. In one group of rats, a laparotomy was performed and 80% of the small bowel resected, reanastomosing proximal jejunum with distal ileum. In the second group (controls), a transection followed by reanastomosis was performed either in the jejunum or ileum. One, two, three, or five days later, the animals were anesthetized, and blood flows to the stomach, jejunum, ileum, cecum, colon, and pancreas were measured using the radioactive microsphere technique. Samples of these tissues were obtained for determination of thymidine incorporation and DNA content. Growth, as evidenced by increases in tissue weight, DNA content, and rate of DNA synthesis, occurred in all tissues. Blood flow was elevated in the pancreas and in bowel segments (ileum and cecum) distal to the site of resection. Gastric, jejunal and colonic blood flows were not affected by bowel resection, in spite of similar trophic changes. Paired-value analyses did not reveal any correlation between blood flow and rate of DNA synthesis. The results of these studies suggest that humoral, rather than metabolic, factors are responsible for the gastrointestinal and pancreatic hyperemia that occurs after small bowel resection.

Effect of exercise on uterine blood flow in the pregnant Pygmy goat

1984 ◽  
Vol 246 (2) ◽  
pp. H207-H212 ◽  
Author(s):  
A. R. Hohimer ◽  
J. M. Bissonnette ◽  
J. Metcalfe ◽  
T. A. McKean
Keyword(s):  
Blood Flow ◽  
Uterine Artery ◽  
Artery Blood Flow ◽  
Normal Birth Weight ◽  
Uterine Blood Flow ◽  
Normal Birth ◽  
Radioactive Microsphere ◽  
Radioactive Microsphere Technique ◽  
Placental Blood ◽  
Placental Blood Flow

Pygmy goats in the last third of pregnancy were trained to walk on a treadmill at rates up to 2.0 mph and up an inclination of 0-15 degrees. Electromagnetic flowmeters were placed unilaterally on a uterine artery, and measurements were made while the goats were standing quietly on the treadmill and during 5 min of exercise. Blood flow fell during exercise in all five animals studied, and this reduction was proportional to the level of exertion. At the highest level of exercise that these animals would voluntarily perform, uterine artery blood flow fell by 32 +/- 3 (SE) % (P less than 0.001) from control. In four additional animals the radioactive microsphere technique was used to measure uterine blood flow at rest and after 5-7 min of exercise. In these animals, exercise caused total uterine blood flow to fall by 18 +/- 10%; cotyledonary (placental) blood flow fell by 8 +/- 13%, while myoendometrial blood flow decreased by 52 +/- 12% (P less than 0.05). Thus nonplacental portions of the pregnant Pygmy goat uterus suffer major reductions in blood flow during exercise. This vasoconstriction may be due to exercise per se or to concomitant hypocapnia or hyperthermia. Singleton and twin kids born to animals that exercised were of normal birth weight.

Chronic portal hypertension: effects on gastrointestinal blood flow distribution

1986 ◽  
Vol 250 (4) ◽  
pp. G535-G539 ◽  
Author(s):  
J. N. Benoit ◽  
W. A. Womack ◽  
R. J. Korthuis ◽  
W. H. Wilborn ◽  
D. N. Granger
Keyword(s):  
Blood Flow ◽  
Portal Hypertension ◽  
Flow Distribution ◽  
Histological Evaluation ◽  
Organ Blood Flow ◽  
Blood Flow Distribution ◽  
Radioactive Microsphere ◽  
Radioactive Microsphere Technique ◽  
Gastrointestinal Blood Flow ◽  
Muscularis Externa

The intramural distribution of blood flow in the gastrointestinal tract was measured in shamoperated control and portal vein-stenosed rats. Total organ blood flow, measured via the radioactive microsphere technique, was elevated in the esophagus (66%), stomach (102%), duodenum (42%), jejunum (52%), ileum (54%), and colon (79%) of portal-hypertensive rats. Histological evaluation of carbonized nonradioactive 15-microns microspheres allowed for fractionation of blood flow within the wall (mucosa, submucosa, and muscularis externa) of each organ. The microsphere distribution pattern indicates that intramural blood flow distribution in all organs was not dramatically affected by chronic portal hypertension. These findings further define the characteristics of the factors responsible for the gastrointestinal hyperemia produced by chronic portal hypertension.

Role of ethanol metabolism in the ethanol-induced increase in splanchnic circulation

1986 ◽  
Vol 250 (4) ◽  
pp. G518-G523 ◽  
Author(s):  
J. P. McKaigney ◽  
F. J. Carmichael ◽  
V. Saldivia ◽  
Y. Israel ◽  
H. Orrego
Keyword(s):  
Blood Flow ◽  
Liver Blood Flow ◽  
Portal Blood Flow ◽  
Splanchnic Blood Flow ◽  
Ethanol Metabolism ◽  
Radioactive Microsphere ◽  
Splanchnic Hemodynamics ◽  
Radioactive Microsphere Technique ◽  
Blood Flow Increase

In this study we report the effect on splanchnic hemodynamics of acute oral ethanol at doses ranging from 0.25 to 4.0 g/kg body wt. Flows were determined by use of a radioactive microsphere technique. Ethanol was found to increase portal blood flow by 23-57%. In awake rats this increase reached a plateau at the 0.5 g/kg dose. In ketamine-anesthetized rats, the increase was observed only at doses of 3.0 g/kg or more, with the response at doses of 0.5, 1.0, and 2.0 g/kg being suppressed by ketamine. Inhibition of alcohol dehydrogenase by intra-arterial administration of 4-methylpyrazole resulted in suppression of the liver blood flow increase after ethanol was administered to awake animals. Ethanol in the range of doses studied did not result in changes in blood glucagon levels. Rats fed ethanol-containing diets for 4 wk and withdrawn for 18 h had the same response to acute oral ethanol as did naive rats. It is suggested that ethanol metabolism mediates the effects of ethanol on splanchnic blood flow. An increase in splanchnic blood flow when concurrent with an increase in liver O2 consumption induced by ethanol might protect the liver from hypoxic damage.

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