THE EFFECT OF INCREASED BLOOD FLOW ON THE RATIO BETWEEN OXYGEN CONSUMPTION AND PULMONARY VENTILATION

1928 ◽  
Vol 86 (2) ◽  
pp. 274-284 ◽  
Author(s):  
Edward D. Churchill
Keyword(s):  
Blood Flow ◽  
Oxygen Consumption ◽  
Pulmonary Ventilation ◽  
Increased Blood Flow

Role of adenosine in postprandial and reactive hyperemia in canine jejunum

1992 ◽  
Vol 263 (4) ◽  
pp. G487-G493 ◽  
Author(s):  
D. R. Sawmiller ◽  
C. C. Chou
Keyword(s):  
Blood Flow ◽  
Oxygen Consumption ◽  
Adenosine Deaminase ◽  
Reactive Hyperemia ◽  
Concentration Difference ◽  
Adenosine Concentration ◽  
Anesthetized Dogs ◽  
Series Of Experiments ◽  
Increased Blood Flow

The role of adenosine in postprandial jejunal hyperemia was investigated by determining the effect of placement of predigested food into the jejunal lumen on blood flow and oxygen consumption before and during intra-arterial infusion of dipyridamole (1.5 microM arterial concn) or adenosine deaminase (9 U/ml arterial concn) in anesthetized dogs. Neither drug significantly altered resting jejunal blood flow and oxygen consumption. Before dipyridamole or deaminase, food placement increased blood flow by 30-36%, 26-42%, and 21-46%, and oxygen consumption by 13-22%, 21-22%, and 26-29%, during 0- to 3-, 4- to 7-, and 8- to 11-min placement periods, respectively. Adenosine deaminase abolished the entire 11-min hyperemia, whereas dipyridamole significantly enhanced the initial 7-min hyperemia (45-49%). Both drugs abolished the initial 7-min food-induced increase in oxygen consumption. Dipyridamole attenuated (14%), whereas deaminase did not alter (28%), the increased oxygen consumption that occurred at 8-11 min. Adenosine deaminase also prevented the food-induced increase in venoarterial adenosine concentration difference. In separate series of experiments, luminal placement of food significantly increased jejunal lymphatic adenosine concentration and release. Also, reactive hyperemia was accompanied by an increase in venous adenosine concentration and release. This study provides further evidence to support the thesis that adenosine plays a role in postprandial and reactive hyperemia in the canine jejunum.

Effect of solute-coupled volume absorption on oxygen consumption in cat ileum.

1979 ◽  
Vol 236 (2) ◽  
pp. E198
Author(s):  
J D Valleau ◽  
D N Granger ◽  
A E Taylor
Keyword(s):  
Blood Flow ◽  
Oxygen Consumption ◽  
Glucose Absorption ◽  
Tyrode Solution ◽  
Recovery Method ◽  
Volume Absorption ◽  
All Solutions ◽  
Volume Recovery ◽  
Oxygen Requirements ◽  
Increased Blood Flow

The effects of solute-coupled volume absorption on blood flow, oxygen consumption, and vascular resistance were analyzed in autoperfused segments of cat ileum. Intestinal absorption was stimulated by placing either Tyrode solution, Tyrode + glucose, or Tyrode + taurocholate into the ileal lumen. Net volume absorption rates (Jv,m) were determined using a volume recovery method. Oxygen consumption (VO2) increased during the absorption of all solutions. The absorption of Tyrode solution plus glucose caused the greatest increase in VO2, whereas Tyrode plus taurocholate resulted in the smallest increase. For Tyrode solution and Tyrode plus glucose absorption, the increased VO2 was due predominantly to an increased blood flow, whereas the increased VO2 with taurocholate resulted from an increased oxygen extraction. A linear relationship between the change in VO2 during transport and Jv,m was aquired for Tyrode solution, and Tyrode + glucose. The results indicate that the oxygen requirements of the absorbing intestine are dependent on both the rate of transport and the solutes being transported.

Oxygen consumption in skeletal muscle during reactive hyperemia

1959 ◽  
Vol 197 (1) ◽  
pp. 190-192 ◽  
Author(s):  
Lloyd R. Yonce ◽  
W. F. Hamilton
Keyword(s):  
Blood Flow ◽  
Oxygen Consumption ◽  
Time Course ◽  
Reactive Hyperemia ◽  
Control Level ◽  
Arterial Occlusion ◽  
Gracilis Muscle ◽  
Oxygen Deficit ◽  
Oxygen Difference ◽  
Increased Blood Flow

The surgical technique of isolation of the blood supply of the gracilis muscle of the dog has been developed for analysis of the oxygen consumption during reactive hyperemia. The time course of the blood flow, A-V oxygen difference and the oxygen consumption follow the same pattern. Immediately after the release of the arterial occlusion, there is an increase in all three values which decay and go below the control level that existed just prior to the occlusion. The increased oxygen consumption during reactive hyperemia is possible primarily by the increased blood flow, although the A-V oxygen difference is increased also. A theoretical oxygen deficit is overpaid by the oxygen consumption during the period of increased blood flow but essentially repaid if the period of decreased blood flow is included.

Jejunal adenosine increases during food-induced jejunal hyperemia

1990 ◽  
Vol 258 (3) ◽  
pp. G370-G376 ◽  
Author(s):  
D. R. Sawmiller ◽  
C. C. Chou
Keyword(s):  
Blood Flow ◽  
Oxygen Consumption ◽  
Normal Saline ◽  
Venous Blood ◽  
Adenosine Release ◽  
Adenosine Concentration ◽  
Anesthetized Dogs ◽  
Arterial Plasma ◽  
Induced Changes ◽  
Increased Blood Flow

If adenosine mediates postprandial intestinal hyperemia, increases in local adenosine release must accompany the hyperemia. We tested this by determining jejunal venous and arterial plasma adenosine concentrations, jejunal blood flow, and oxygen consumption before and during placement of normal saline or predigested food plus bile into the jejunal lumen of anesthetized dogs. Adenosine concentrations were measured by high-pressure liquid chromatography. Luminal placement of food significantly increased blood flow (+46%), oxygen consumption (+40%), venous adenosine concentration (+56 nM), and adenosine release (+1.7 nmol.min-1.100 g tissue-1) during the initial 3 min of placement. Whereas blood flow and oxygen consumption remained elevated for the entire 15-min placement period, venous adenosine concentration and release returned to control levels at 7 and 11 min after placement, respectively. Placement of the same volume of normal saline did not significantly alter any variables measured, indicating that the food-induced changes were because of constituents of food. In conclusion, introduction of predigested food into the jejunal lumen significantly increases adenosine releases into the local venous blood during the initial several minutes of food placement. The increased adenosine production and release may play a role in postprandial jejunal hyperemia.

Diastolic pressure and peripheral resistance during stellate ganglion stimulation

1963 ◽  
Vol 204 (1) ◽  
pp. 71-72 ◽  
Author(s):  
Edward D. Freis ◽  
Jay N. Cohn ◽  
Thomas E. Liptak ◽  
Aristide G. B. Kovach
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Cardiac Output ◽  
Total Peripheral Resistance ◽  
Diastolic Pressure ◽  
Stellate Ganglion ◽  
Peripheral Resistance ◽  
Resistance Vessels ◽  
Left Stellate Ganglion ◽  
Increased Blood Flow

The mechanism of the diastolic pressure elevation occurring during left stellate ganglion stimulation was investigated. The cardiac output rose considerably, the heart rate remained essentially unchanged, and the total peripheral resistance fell moderately. The diastolic rise appeared to be due to increased blood flow rather than to any active changes in resistance vessels.

alpha-Adrenergic control of oxygen delivery to myocardium during exercise in conscious dogs

1982 ◽  
Vol 242 (5) ◽  
pp. H805-H809 ◽  
Author(s):  
G. R. Heyndrickx ◽  
P. Muylaert ◽  
J. L. Pannier
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Oxygen Consumption ◽  
Coronary Blood Flow ◽  
Coronary Sinus ◽  
Oxygen Delivery ◽  
Left Ventricular ◽  
Conscious Dogs ◽  
Adrenergic Blockade ◽  
Adrenergic Control

alpha-Adrenergic control of the oxygen delivery to the myocardium during exercise was investigated in eight conscious dogs instrumented for chronic measurements of coronary blood flow, left ventricular (LV) pressure, aortic blood pressure, and heart rate and sampling of arterial and coronary sinus blood. After alpha-adrenergic receptor blockade a standard exercise load elicited a significantly greater increase in heart rate, rate of change of LV pressure (LV dP/dt), LV dP/dt/P, and coronary blood flow than was elicited in the unblocked state. In contrast to the response pattern during control exercise, there was no significant change in coronary sinus oxygen tension (PO2), myocardial arteriovenous oxygen difference, and myocardial oxygen delivery-to-oxygen consumption ratio. It is concluded that the normal relationship between myocardial oxygen supply and oxygen demand is modified during exercise after alpha-adrenergic blockade, whereby oxygen delivery is better matched to oxygen consumption. These results indicate that the increase in coronary blood flow and oxygen delivery to the myocardium during normal exercise is limited by alpha-adrenergic vasoconstriction.

Effects of nicotine on canine intestinal blood flow and oxygen consumption

1984 ◽  
Vol 246 (2) ◽  
pp. G195-G203
Author(s):  
R. H. Gallavan ◽  
Y. Tsuchiya ◽  
E. D. Jacobson
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Oxygen Consumption ◽  
Muscle Tension ◽  
Intestinal Blood Flow ◽  
Mesenteric Blood Flow ◽  
State Response ◽  
Arterial Blood ◽  
Intestinal Circulation

The purpose of this study was to determine the effects of nicotine on intestinal blood flow and oxygen consumption. The intravenous infusion of nicotine at doses corresponding to those experienced by smokers produced a transient increase in systemic arterial blood pressure and mesenteric blood flow. Subsequently a steady-state response developed that consisted of a reduction in mesenteric blood flow due to both a decrease in blood pressure and an increase in intestinal vascular resistance. This increase in resistance was probably due to increased levels of circulating catecholamines. The intra-arterial infusion of nicotine into the intestinal circulation at doses experienced by the average smoker had no effect on either intestinal blood flow or oxygen consumption. Similarly, under in vitro conditions nicotine had no direct effect on intestinal vascular smooth muscle tension. Thus, nicotine appears to reduce intestinal blood flow indirectly as a result of its systemic effects.

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