Estimated regional blood flow by rubidium 86 distribution during arousal from hibernation

1962 ◽  
Vol 203 (2) ◽  
pp. 266-270 ◽  
Author(s):  
Robert W. Bullard ◽  
Gordon E. Funkhouser
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Ground Squirrel ◽  
Regional Blood Flow ◽  
Regional Distribution ◽  
Arousal Level ◽  
Blood Flows

The local organ or tissue blood flows during the process of arousal from hibernation have been estimated in the 13-lined ground squirrel by the Sapirstein method, which consists of the measurement of the regional distribution of injected rubidium 86. The studies demonstrated that during arousal there is a confinement of blood flow to the thoracic regions. After the heart rate has attained 100 beats/min, blood flow increases to the anterior portions of the animal. At the arousal level characterized by a heart rate of 200 beats/min, blood flow to anterior and thoracic tissue had attained levels almost equal to control flows. Posterior tissue flows were still much lower than control flows. The centralization of blood flow to thoracic and anterior tissues did not occur in the rat in the hypothermic state.

Regional blood flow in conscious resting rats determined by microsphere distribution

1993 ◽  
Vol 74 (1) ◽  
pp. 203-210 ◽  
Author(s):  
I. Kuwahira ◽  
N. C. Gonzalez ◽  
N. Heisler ◽  
J. Piiper
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Regional Blood Flow ◽  
Sampling Technique ◽  
Organ Blood Flow ◽  
Sprague Dawley ◽  
Blood Flows ◽  
Hindlimb Muscles ◽  
Acclimation Period ◽  
The Difference

To determine organ blood flow in the resting state, a box was designed to keep conscious untrained rats minimally disturbed. Blood pressure, heart rate, and organ blood flow, determined by the microsphere distribution and reference sampling technique, were measured in 11 Sprague-Dawley rats. After an acclimation period, 15-microns-diameter microspheres labeled with 113Sn were infused into the ascending aorta, a reference blood sample was withdrawn from the caudal artery, and organ blood flows were computed according to standard procedures. The average values of heart rate (365 beats/min) and blood flow to the brain (45 ml.min-1.100 g-1) and hindlimb muscles (15 ml.min-1.100 g-1) were significantly lower than most values reported earlier, whereas splanchnic blood flow was significantly higher (106 ml.min-1.100 g-1). Blood flow to the soleus muscle, which is considered the most active for postural maintenance, was relatively high (99 ml.min-1.100 g-1). The combination of low skeletal muscle and high visceral blood flows observed in these experiments suggests a low sympathetic tone, which is consistent with the low level of circulating catecholamines also observed in this study. It is hypothesized that the difference between our present and previous results is a lower level of stress, attributable to a more complete acclimation to the experimental environment.

Regional distribution of blood flow of dogs during graded dynamic exercise

1987 ◽  
Vol 63 (6) ◽  
pp. 2269-2277 ◽  
Author(s):  
T. I. Musch ◽  
D. B. Friedman ◽  
K. H. Pitetti ◽  
G. C. Haidet ◽  
J. Stray-Gundersen ◽  
...  
Keyword(s):  
Blood Flow ◽  
Maximal Exercise ◽  
Regional Blood Flow ◽  
Regional Distribution ◽  
Work Load ◽  
Work Intensity ◽  
Semitendinosus Muscle ◽  
Blood Flows ◽  
Flow Response ◽  
Semimembranosus Muscle

The regional blood flow response to progressive treadmill exercise was measured with radioactive microspheres in 25 untrained mongrel dogs. Incremental increases in work intensity resulted in corresponding increases in blood flows to the gracilis, gastrocnemius, semimembranosus, and semitendinosus muscles of the hindlimb and to the heart. During maximal exercise, blood flow was greatest in the semimembranosus muscle and lowest in the semitendinosus muscle (342 and 134 ml–1.100 g tissue-1.min-1, respectively). Exercise produced a decrease in blood flow to the temporalis muscle, which was classified as nonlocomotive in function. Blood flows to the stomach, pancreas, and large intestine decreased at the lowest exercise work load and remained diminished throughout the continuum to maximal exercise. Blood flows to the small intestine and spleen were maintained during submaximal exercise but were reduced by 50% at maximal O2 consumption (VO2max). No changes in blood flows to the kidneys, adrenal glands, liver, and brain were found. These results demonstrate that 1) renal blood flow is maintained at resting levels during exercise in untrained dogs; 2) blood flow changes in the various organs of the splanchnic region of dogs during exercise are heterogeneous; and 3) blood flows to the working skeletal muscles of dogs progressively increase with increasing work loads up to VO2max.

An autoradiographic study of regional distribution of gastric mucosal blood flow

1988 ◽  
Vol 254 (4) ◽  
pp. G566-G574
Author(s):  
W. J. Angerson ◽  
J. G. Geraghty ◽  
D. C. Carter
Keyword(s):  
Blood Flow ◽  
Regional Distribution ◽  
Mucosal Blood Flow ◽  
Gastric Mucosal Blood Flow ◽  
Autoradiographic Study ◽  
Acute Injury ◽  
Antral Mucosa ◽  
Blood Flows ◽  
Greater Curvature ◽  
Mucosal Folds

Iodo[14C]antipyrine autoradiography was used to measure gastric mucosal blood flow in anesthetized rats and to study regional distribution. Blood flows of 61 +/- 8 ml.100 g-1.min-1 (means +/- SE) in corpus and 84 +/- 9 ml.100 g-1.min-1 in antral mucosa compared well with previously reported measurements by hydrogen clearance. Blood flow in the crests of corpus mucosal folds was significantly higher than in the valleys between folds, indicating that the greater susceptibility of the former areas to acute injury, documented in several studies, is not associated with a perfusion defect in the resting stomach. Corpus mucosal blood flow was also higher in the side walls of the stomach than in the greater curvature region, and in distal than in proximal locations. No systematic regional variations within antral mucosa were demonstrated.

Regional circulatory responses to hypocapnia and hypercapnia in bar-headed geese

1986 ◽  
Vol 250 (3) ◽  
pp. R499-R504 ◽  
Author(s):  
F. M. Faraci ◽  
M. R. Fedde
Keyword(s):  
Blood Flow ◽  
Regional Blood Flow ◽  
Muscle Blood Flow ◽  
Pectoral Muscle ◽  
Blood Flows ◽  
Arterial Blood ◽  
Blood Flow Reduction ◽  
Extreme Altitude ◽  
Anser Indicus ◽  
O2 Delivery

To investigate mechanisms that may allow birds to tolerate extreme high altitude (hypocapnic hypoxia), we examined the effects of severe hypocapnia and moderate hypercapnia on regional blood flow in bar-headed geese (Anser indicus), a species that flies at altitudes up to 9,000 m. Cerebral, coronary, and pectoral muscle blood flows were measured using radioactive microspheres, while arterial CO2 tension (PaCO2) was varied from 7 to 62 Torr in awake normoxic birds. Arterial blood pressure was not affected by hypocapnia but increased slightly during hypercapnia. Heart rate did not change during alterations in PaCO2. Severe hypocapnia did not significantly alter cerebral, coronary, or pectoral muscle blood flow. Hypercapnia markedly increased cerebral and coronary blood flow, but pectoral muscle blood flow was unaffected. The lack of a blood flow reduction during severe hypocapnia may represent an important adaptation in these birds, enabling them to increase O2 delivery to the heart and brain at extreme altitude despite the presence of a very low PaCO2.

Regional blood flow and capillary permeability in the ethylnitrosourea-induced rat glioma

1981 ◽  
Vol 55 (6) ◽  
pp. 922-928 ◽  
Author(s):  
Kazuo Yamada ◽  
Toru Hayakawa ◽  
Yukitaka Ushio ◽  
Norio Arita ◽  
Amami Kato ◽  
...  
Keyword(s):  
Blood Flow ◽  
Brain Tissue ◽  
Evans Blue ◽  
Capillary Permeability ◽  
Regional Blood Flow ◽  
Blue Staining ◽  
Content Type ◽  
Rat Glioma ◽  
Blood Flows ◽  
Diameter Reduction

✓ Regional cerebral blood flow and capillary permeability of rat brains bearing ethylnitrosourea-induced gliomas of various size were investigated with 14C-antipyrine autoradiography and Evans blue staining. In the small tumors (<2 mm in diameter), blood flow was uniformly reduced when compared to the adjacent brain. Even in tiny tumors (0.3 to 0.4 mm in diameter), reduction in blood flow was evident. In the medium (2 to 4 mm in diameter) and large (> 4 mm in diameter) tumors, the blood flow increased or decreased depending on the part of the tumor examined. The necrotic center and peripheral edge had low blood flows, whereas the viable portion adjacent to the necrotic center had high blood flows. Blood flow in the brain tissue adjacent to medium and large tumors was lower than control brain tissue, probably due to local edema. Leakage of intravenous Evans blue in the tissue was only evident in the large tumors with central necrosis. The present findings suggest that neovascularization of the tumor may occur when the tumor reaches a certain size, and leaky new vessels may be the cause of brain edema associated with tumor.

Regional distribution of blood flow in awake heat-stressed baboons

1979 ◽  
Vol 237 (6) ◽  
pp. H705-H712 ◽  
Author(s):  
J. R. Hales ◽  
L. B. Rowell ◽  
R. B. King
Keyword(s):  
Blood Flow ◽  
Heat Stress ◽  
Regional Blood Flow ◽  
Regional Distribution ◽  
Renal Vasoconstriction ◽  
Suitable Animal Model ◽  
Mean Pressure ◽  
Subcutaneous Adipose ◽  
Arterial Po2 ◽  
The Brain

Radioactive microspheres (containing six different nuclide labels) were used to measure blood flow (BF) to most major organs of eight conscious baboons during heat stress. Cardiac output (CO), arterial mean pressure, and arterial PO2, PCO2, and pH did not change, but heart rate increased and stroke volume fell as body temperature increased by as much as 2.56 degrees C. Skin BF increased in all regions sampled so that the fraction of CO distributed to skin (not including feet and hands) increased from 3% (control) to 14%. Increased skin BF was compensated for by decreases in splanchnic (intestines, stomach, pancreas, and spleen) (35%), renal (27%), and possibly muscle BF. There was no change in BF to the brain, spinal cord, coronary, or subcutaneous adipose tissue during heating. Therefore, baboons show a generalized redistribution of BF during heat stress, so that increments in skin BF are provided without increases in CO, whereas man depends on changes in both; despite this latter difference between the baboon and man, the similarity in magnitude of the splanchnic and renal vasoconstriction between the two primates may indicate that the baboon would be a suitable animal model for investigations into mechanisms of changes in regional blood flow in man during heat stress.

The effects of artificial lung inflation on pulmonary blood flow and heart rate in the turtle Trachemys scripta.

1997 ◽  
Vol 200 (19) ◽  
pp. 2539-2545
Author(s):  
J Herman ◽  
T Wang ◽  
A W Smits ◽  
J W Hicks
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Lung Volume ◽  
Pulmonary Blood Flow ◽  
Trachemys Scripta ◽  
Spontaneous Ventilation ◽  
Lung Inflation ◽  
Cardiovascular Changes ◽  
Blood Flows ◽  
Stimulation Of

As for most ectothermic vertebrates, the breathing pattern of turtles is episodic, and pulmonary blood flow (Qpul) and heart rate (fH) normally increase several-fold during spontaneous ventilation. While some previous studies suggest that these cardiovascular changes are caused by stimulation of pulmonary stretch receptors (PSRs) during ventilation, it has been noted in other studies that blood flows often change prior to the initiation of breathing. Given the uncertainty regarding the role of PSRs in the regulation of central vascular blood flows, we examined the effect of manipulating lung volume (and therefore PSR stimulation) on blood flows and heart rate in the freshwater turtle Trachemys scripta. Turtles were instrumented with blood flow probes on the left aortic arch and the left pulmonary artery for measurements of blood flow, and catheters were inserted into both lungs for manipulation of lung volume. In both anaesthetized and fully recovered animals, reductions or increases in lung volume by withdrawal of lung gas or injection of air, N2, O2 or 10% CO2 (in room air) had no effect on blood flows. Furthermore, simulations of normal breathing bouts by withdrawal and injection of lung gas did not alter Qpul or fH. We conclude that stimulation of PSRs is not sufficient to elicit cardiovascular changes and that the large increase in Qpul and fH normally observed during spontaneous ventilation are probably caused by a simultaneous feedforward control of central origin.

Regional blood flow in canine atria during exercise

1993 ◽  
Vol 265 (2) ◽  
pp. H629-H632 ◽  
Author(s):  
R. P. Bauman ◽  
J. C. Rembert ◽  
J. C. Greenfield
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Left Atrial ◽  
Regional Blood Flow ◽  
Similar Degree ◽  
Moderate Exercise ◽  
Nutrient Flow ◽  
Right Atria

Global and regional atrial blood flow was measured with radioisotope-labeled microspheres in eight dogs during rest and two levels of exercise. Both mean right and left atrial blood flow increased significantly (P < 0.05) to a similar degree with each level of exercise (right atria: 0.27 +/- 0.04, 0.89 +/- 0.11, and 1.57 +/- 0.21 ml.min-1 x g-1; left atria: 0.35 +/- 0.04, 0.90 +/- 0.09, and 1.61 +/- 0.17 ml.min-1 x g-1). Atrial blood flow during exercise is greater than anticipated if increased heart rate was the sole cause. In both right and left atria the ratio of appendage to nonappendage flow was significantly (P < 0.005) less than one during resting conditions (0.42 +/- 0.04 and 0.81 +/- 0.05, respectively), not different from unity during mild exercise, and significantly (P < 0.02) greater than one during moderate exercise (1.10 +/- 0.03 and 1.16 +/- 0.05, respectively). This disparity in the blood flow to the appendage and nonappendage regions suggests that the appendage plays an augmented hemodynamic role during exercise, thus requiring a larger proportion of the nutrient flow.

Cardiovascular adjustments to laboratory diving in beavers and nutria

1982 ◽  
Vol 242 (5) ◽  
pp. R434-R440
Author(s):  
T. McKean
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Regional Blood Flow ◽  
Castor Canadensis ◽  
Venous Blood ◽  
Regional Distribution ◽  
Blood Gases ◽  
Myocastor Coypus ◽  
Recovery From Anesthesia ◽  
Rate Of Decline

Beavers (Castor canadensis) and nutria (Myocastor coypus) were anesthetized with halothane and catheters placed in the left ventricle, aorta and pulmonary artery, right ventricle or right atrium. The animals were strapped to a board and following recovery from anesthesia the following measurements were taken: regional distribution of blood flow, cardiac output, O2 consumption, arterial and venous blood gases, and pH. The animal was then immersed in 15-20 degrees C water for up to 2.75 min (nutria) or 4 min (beaver) and the measurements repeated. Heart rate and cardiac output decreased by 80 and 75%, respectively. Arterial and venous oxygen partial pressure and content fell as did pH whereas CO2 pressures rose during diving. Oxygen consumption at rest was 124 and 102% of that predicted on the basis of body mass for the beaver and nutria, respectively. Rate of decline of O2 stores during diving decreased by 93% in beavers and 89% in nutria compared to the predive value. Regional blood flow decreased to all organs except the adrenals, heart, and lungs. Blood flow to the brain increased during diving.

Age-related changes in regional blood flow in the rat

1985 ◽  
Vol 249 (3) ◽  
pp. H485-H491 ◽  
Author(s):  
R. F. Tuma ◽  
G. L. Irion ◽  
U. S. Vasthare ◽  
L. A. Heinel
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Cardiac Index ◽  
Regional Blood Flow ◽  
Adult Rats ◽  
Blood Flows ◽  
Arterial Blood ◽  
Anesthetized Rats ◽  
Regional Blood Flows ◽  
Central Hemodynamic

The purpose of this investigation was to characterize the changes in regional blood flow and central hemodynamic measures that occur in the rat as a result of the aging process. The isotope-labeled microsphere technique was used to measure cardiac output and regional blood flows in conscious and anesthetized adult (12 mo) and senescent (24 mo) Fischer 344 virgin female rats. No significant changes were observed in central hemodynamic measurements or regional blood flows in conscious rats with the exception of a 25% reduction in splenic blood flow. Pentobarbital anesthesia significantly reduced cardiac index and heart rate but elevated total peripheral resistance and mean arterial blood pressure. There was a decrease in blood flow to skeletal muscle, spleen, duodenum, stomach, and brain tissue samples and increased hepatic arterial blood flow in both age groups. The use of anesthesia caused a greater reduction in the cardiac index and brain blood flow in the senescent anesthetized rats than in the adult rats. Heart and kidney blood flows were decreased by anesthesia in the senescent rats but not in the adult rats. Skeletal muscle blood flow, however, was significantly greater in the senescent anesthetized rats than in the younger anesthetized animals. Although body weight and organ weights of the liver, spleen, kidneys, stomach, heart, and brain were significantly greater for the senescent rats, no differences could be demonstrated in tibial length or lean body mass.

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