CARDIOVASCULAR EFFECTS OF PRONETHALOL IN THE DOG

1965 ◽  
Vol 43 (3) ◽  
pp. 411-420 ◽  
Author(s):  
M. A. Chiong ◽  
P. F. Binnion ◽  
J. D. Hatcher
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Oxygen Consumption ◽  
Stroke Volume ◽  
Peripheral Resistance ◽  
Systolic Pressure ◽  
Cardiovascular Effects ◽  
Stroke Work ◽  
Right Ventricular Systolic Pressure ◽  
Ventricular Systolic Pressure

The cardiovascular effects of an intravenous injection of pronethalol (2.5 mg/kg) and the effect of this agent on the cardiovascular changes induced by an infusion of adrenaline (0.2 μg/kg per minute) were investigated in intact anaesthetized dogs. Fifteen minutes after the administration of pronethalol, significant increases were observed in oxygen consumption, right ventricular systolic pressure, and haematocrit, and decreases in arterial blood pressure and total peripheral resistance. Arterial hypotension and a fall in stroke work were the only changes noted at 30 minutes. There was considerable variability in cardiac output, stroke volume, and heart rate but, on the average, no significant change was observed. Pretreatment with pronethalol abolished or significantly reduced the adrenaline-induced rises in cardiac output, heart rate, stroke volume, stroke work, oxygen consumption, right ventricular systolic pressure, and arterial haematocrit, and reversed the changes in diastolic arterial pressure and peripheral resistance. It is concluded that pronethalol is not devoid of sympathomimetic activity and that it effectively blocks the adrenaline responses mediated by β-receptors.

Hemodynamic responses to acute carboxyhemoglobinemia in the rat

1983 ◽  
Vol 244 (3) ◽  
pp. H320-H327 ◽  
Author(s):  
W. E. Kanten ◽  
D. G. Penney ◽  
K. Francisco ◽  
J. E. Thill
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Mean Arterial Pressure ◽  
Cardiac Index ◽  
Arterial Pressure ◽  
Stroke Volume ◽  
Peripheral Resistance ◽  
Systolic Pressure ◽  
Left Ventricular ◽  
Stroke Work

The effects of carbon monoxide on the hemodynamics of the adult rat were investigated. A number of parameters were measured using an open-chest, chloralose-urethan anesthetized preparation. Our experiments showed this anesthetic agent to have several advantages over pentobarbital sodium. One group inhaled 150 ppm CO for 0.5-2 h, carboxyhemoglobin (HbCO) reaching 16%. Heart rate, cardiac output, cardiac index, dF/dtmax (aortic), and stroke volume rose significantly; mean arterial pressure, total peripheral resistance, and left ventricular systolic pressure fell, whereas stroke work, left ventricular dP/dtmax, and stroke power changed little. These effects were evident at a HbCO saturation as low as 7.5% (0.5 h). A second group inhaled 500 ppm CO for 5-48 h, HbCO reaching 35-38%. The same parameters changed in the same direction as in the first group, with mean arterial pressure and peripheral resistance remaining depressed, while heart rate, cardiac output, cardiac index, and stroke volume remained elevated. Heart rate and arterial systolic pressure were also monitored in conscious rats; rats in one group inhaled 500 ppm CO for 24 h, and rats in a second group were injected with a bubble of pure CO ip. In both cases heart rate was sharply elevated and blood pressure depressed as HbCO saturation increased. Both parameters recovered on CO washout. There was no significant difference between the response to inhaled vs. injected CO.

Cardiovascular Effects of Moxibustion at Jen Chung (Go-26) during Halothane Anesthesia in Dogs

1975 ◽  
Vol 03 (03) ◽  
pp. 245-261 ◽  
Author(s):  
Do Chil Lee ◽  
Myung O. Lee ◽  
Donald H. Clifford
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Stroke Volume ◽  
Total Peripheral Resistance ◽  
Venous Pressure ◽  
Peripheral Resistance ◽  
Cardiovascular Effects ◽  
Halothane Anesthesia

The cardiovascular effects of moxibustion at Jen Chung (Go-26) in 10 dogs under halothane anesthesia were compared to 5 dogs under halothane anesthesia without moxibustion and 5 dogs under halothane anesthesia in which moxibustion was effected at a neutral or non-acupuncture site. Cardiac output, stroke volume, heart rate, mean arterial pressure, central venous pressure, total peripheral resistance, pH, PaCO2, PaO2 and base deficit were measured over a two-hour period. A significant increase in cardiac output and stroke volume and a significant decrease in the total peripheral resistance were observed in the group which was stimulated by moxibustion at Jen Chun (Go-26). Heart rate, mean arterial pressure and pulse pressure were significantly increase during the early part of the two-hour period in the same group. The cardiovascular effects of moxibustion at Jen Chung (Go-26) which were observed at the end of the two hours were also present in two dogs in which measurements were continued for two additional hours.

Mechanism of higher oxygen consumption rate: pressure-loaded vs. volume-loaded heart

1982 ◽  
Vol 242 (6) ◽  
pp. H942-H948 ◽  
Author(s):  
H. Suga ◽  
R. Hisano ◽  
S. Hirata ◽  
T. Hayashi ◽  
I. Ninomiya
Keyword(s):  
Oxygen Consumption ◽  
Stroke Volume ◽  
Consumption Rate ◽  
Systolic Pressure ◽  
Ventricular Wall ◽  
Stroke Work ◽  
Ventricular Systolic Pressure ◽  
Pressure Load ◽  
Volume Load ◽  
Ejection Pressure

The greater cardiac oxygen consumption (VO2) under pressure than under volume load has been accounted for by the greater ventricular wall force under pressure load. We cannot fully agree with this because the wall force has not always been uniquely correlated with VO2. We attempted to account for the greater VO2 under pressure load by the ventricular systolic pressure-volume area (PVA), which we previously showed uniquely correlated with VO2. In isolated supported canine hearts, we produced servo-controlled ejecting contractions the stroke work (SW) of which was doubled from control by doubling ejection pressure (P) with comparable stroke volume (SV) and by doubling Sv with comparable P. Despite comparable increments in SW from 370 to 680 mmHg.ml under two different loads, VO2 and PVA increased significantly more under pressure load (from 0.033 ml O2/beat and 800 mmHg.ml to 0.0560 and 1,800, respectively) than under volume load (increasing to 0.038 and 1,200, respectively; P less than 0.01). These results suggested to us a new mechanism underlying the greater VO2 under pressure load.

Inhibition of the Cardiovascular Effects of Acupuncture (Moxibustion) by Phenotolamine in Dogs During Halothane Anesthesia

1976 ◽  
Vol 04 (02) ◽  
pp. 153-161 ◽  
Author(s):  
Myung O. Lee ◽  
Do Chil Lee ◽  
Donald H. Clifford
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Stroke Volume ◽  
Total Peripheral Resistance ◽  
Peripheral Resistance ◽  
Cardiovascular Effects ◽  
Blocking Agent ◽  
Halothane Anesthesia

The cardiovascular effects of acupuncture, moxibustion by electrocautery, at Jen Chung (Go-26) and phentolamine (0.1 mg/kg-i.v.) alone were compared to phentolamine (0.1 mg/kg-i.v.) prior to moxibustion at Go-26 in groups of ten dogs under 0.75 percent halothane anesthesia. Cardiac output, stroke volume, heart rate, mean arterial pressure, central venous pressue, total peripheral resistance, pH, PaCO2, PaO2 and base deficit were measured over a two hour period. A significant increase (5% level) in cardiac output, stroke volume, heart rate, mean arterial pressure, pulse pressure and significant decrease in total peripheral resistance were observed following acupuncture, moxibustion with electrocautery, at Jen Chung (Go-26) in dogs under halothane anesthesia. These effects were inhibited by pretreatment with the alpha blocking agent, phentolamine (0.1mg/kg-i.v.). The cardiovascular effects of phentolamine (0.1mg/kg-i.v.) alone were similar to those of dogs in which phenotolamine was administered prior to moxibustion.

Cardiovascular response to graded exercise in the sympathectomized-vagotomized dog

1963 ◽  
Vol 204 (2) ◽  
pp. 291-296 ◽  
Author(s):  
Edmundo Ashkar ◽  
William F. Hamilton
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Oxygen Consumption ◽  
Mean Arterial Pressure ◽  
Stroke Volume ◽  
Cardiovascular Response ◽  
Peripheral Resistance ◽  
Graded Exercise ◽  
Oxygen Difference

Seven dogs who ran well on a motor-driven treadmill were completely sympathectomized (including adrenal denervation) and subjected to unilateral vagotomy below the recurrent laryngeal branch. After recovery and retraining, a terminal experiment was performed in which, after completing the vagotomy, direct Fick determinations of cardiac output and continuous recordings of mean arterial pressure, heart rate, and oxygen consumption were made at rest and during increasing exercise The results were compared with those described by Barger et al. ( Am. J. Physiol. 184: 613, 1956) for normal dogs running at smaller speeds and grades. The heart rate of the operated dogs increased from 117 to 134. Barger's normal dogs doubled their heart rate. The A-V oxygen difference increased with work slightly less than Barger's normal dogs but the scatter in both groups was wide, as was the case with the stroke volume. The resting cardiac output was nearly normal in the operated dogs but increased only 34% with exercise, as against 200–300% in Barger's normals. Oxygen consumption increased about twofold as against the expected normal of three- to sevenfold. Peripheral resistance in both groups went down about 40%. The blood pressure in the normal increased substantially while that in the operated dogs fell about 20% to an average of 60 mm Hg.

Submaximal Cardiovascular Responses to Exercise in Children: Treadmill versus Cycle Ergometer

1997 ◽  
Vol 9 (4) ◽  
pp. 331-341
Author(s):  
Kenneth R. Turley ◽  
Jack H. Wilmore
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Regression Analysis ◽  
Oxygen Consumption ◽  
Stroke Volume ◽  
Peripheral Resistance ◽  
Cardiovascular Responses ◽  
Cycle Ergometer ◽  
Individual Values ◽  
Oxygen Difference

This study investigated whether cardiovascular responses at a given submaximal oxygen consumption (V̇O2, L · min-1) are different between the treadmill (TM) and cycle ergometer (CE). Submaximal cardiovascular measurements were obtained at three work rates on both the TM and CE in 7- to 9-year-old children (12 males and 12 females). Using regression analysis, it was determined that there were no differences between the TM and CE in cardiac output (L · min-1), stroke volume (SV, ml · beat-1) or heart rate (beats · min-1) at a given V̇O2 (L · min-1). There were differences in the total peripheral resistance (TPR, units) and arterial-venous oxygen difference (a-vO2 diff, ml · 100 ml-1) to V̇O2 (L · min-1) relationship. While there were statistically significant differences in TPR and a-vO2 diff between the two modalities, there was substantial overlap of individual values at any given submaximal V̇O2, thus the physiological significance is questionable. Hence, we conclude that in 7- to 9-yearold children there are no differences in submaximal cardiovascular responses between the CE and TM.

Cardiovascular changes in the exercising emu

1983 ◽  
Vol 104 (1) ◽  
pp. 193-201 ◽  
Author(s):  
B. Grubb ◽  
D. D. Jorgensen ◽  
M. Conner
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Oxygen Consumption ◽  
Stroke Volume ◽  
Oxygen Content ◽  
Body Mass ◽  
Fold Increase ◽  
Exercise Heart Rate ◽  
Rate Of Oxygen Consumption ◽  
Cardiovascular Variables

Cardiovascular variables were studied as a function of oxygen consumption in the emu, a large, flightless ratite bird well suited to treadmill exercise. At the highest level of exercise, the birds' rate of oxygen consumption (VO2) was approximately 11.4 times the resting level (4.2 ml kg-1 min-1). Cardiac output was linearly related to VO2, increasing 9.5 ml for each 1 ml increase in oxygen consumption. The increase in cardiac output is similar to that in other birds, but appears to be larger than in mammals. The venous oxygen content dropped during exercise, thus increasing the arteriovenous oxygen content difference. At the highest levels of exercise, heart rate showed a 3.9-fold increase over the resting rate (45.8 beats min-1). The mean resting specific stroke volume was 1.5 ml per kg body mass, which is larger than shown by most mammals. However, birds have larger hearts relative to body mass than do mammals, and stroke volume expressed per gram of heart (0.18 ml g-1) is similar to that for mammals. Stroke volume showed a 1.8-fold increase as a result of exercise in the emus, but a change in heart rate plays a greater role in increasing cardiac output during exercise.

Effect of sympathetic blockade on diurnal variation of hemodynamic patterns

1989 ◽  
Vol 256 (3) ◽  
pp. R778-R785 ◽  
Author(s):  
M. I. Talan ◽  
B. T. Engel
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Total Peripheral Resistance ◽  
Peripheral Resistance ◽  
Base Line ◽  
Sympathetic Blockade ◽  
Selective Blockade ◽  
Arterial Blood

Heart rate, stroke volume, and intra-arterial blood pressure were monitored continuously in each of four monkeys, 18 consecutive h/day for several weeks. The mean heart rate, stroke volume, cardiac output, systolic and diastolic blood pressure, and total peripheral resistance were calculated for each minute and reduced to hourly means. After base-line data were collected for approximately 20 days, observation was continued for equal periods of time under conditions of alpha-sympathetic blockade, beta-sympathetic blockade, and double sympathetic blockade. This was achieved by intra-arterial infusion of prazosin, atenolol, or a combination of both in concentration sufficient for at least 75% reduction of response to injection of agonists. The results confirmed previous findings of a diurnal pattern characterized by a fall in cardiac output and a rise in total peripheral resistance throughout the night. This pattern was not eliminated by selective blockade, of alpha- or beta-sympathetic receptors or by double sympathetic blockade; in fact, it was exacerbated by sympathetic blockade, indicating that the sympathetic nervous system attenuates these events. Because these findings indicate that blood volume redistribution is probably not the mechanism mediating the observed effects, we have hypothesized that a diurnal loss in plasma volume may mediate the fall in cardiac output and that the rise in total peripheral resistance reflects a homeostatic regulation of arterial pressure.

Cardiopulmonary effects of continuous pressure breathing in hypothermic dogs

1965 ◽  
Vol 20 (4) ◽  
pp. 669-674 ◽  
Author(s):  
J. Salzano ◽  
F. G. Hall
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Oxygen Consumption ◽  
Stroke Volume ◽  
Negative Pressure ◽  
Alveolar Ventilation ◽  
Positive Pressure ◽  
Negative Pressure Breathing ◽  
Continuous Positive Pressure ◽  
Respiratory Dead Space

Continuous pressure breathing was studied in hypothermic anesthetized dogs. Alveolar ventilation decreased during continuous positive-pressure breathing and increased during continuous negative-pressure breathing. The changes in alveolar ventilation were due to changes in respiratory rate as well as in respiratory dead space. Cardiac output fell significantly during continuous positive-pressure breathing due to a reduction in heart rate and stroke volume. During continuous negative-pressure breathing cardiac output was only slightly greater than during control as a result of a fall in heart rate and an increase in stroke volume. Oxygen consumption was reduced to 60% of control during continuous positive-pressure breathing of 16 cm H2O but was 25% greater than control during continuous negative-pressure breathing. Qualitatively, CO2 production changed as did O2 consumption but was different quantitatively during continuous negative-pressure breathing indicating hyperventilation due to increased respiratory rate. Mean pulmonary artery pressures and pulmonary resistance varied directly with the applied intratracheal pressure. The results indicate that the hypothermic animal can tolerate an imposed stress such as continuous pressure breathing and can increase its oxygen consumption during continuous negative-pressure breathing as does the normothermic animal. hypothermia; respiratory dead space; metabolic rate; cardiac output Submitted on December 8, 1964

Orthostatic intolerance after spaceflight

1996 ◽  
Vol 81 (1) ◽  
pp. 7-18 ◽  
Author(s):  
J. C. Buckey ◽  
L. D. Lane ◽  
B. D. Levine ◽  
D. E. Watenpaugh ◽  
S. J. Wright ◽  
...  
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Space Shuttle ◽  
Orthostatic Intolerance ◽  
Peripheral Resistance ◽  
Systemic Hemodynamic ◽  
Vasoconstrictor Response ◽  
Before And After ◽  
Underlying Mechanisms

Orthostatic intolerance occurs commonly after spaceflight, and important aspects of the underlying mechanisms remain unclear. We studied 14 individuals supine and standing before and after three space shuttle missions of 9-14 days. After spaceflight, 9 of the 14 (64%) crew members could not complete a 10-min stand test that all completed preflight. Pre- and postflight supine hemodynamics were similar in both groups except for slightly higher systolic and mean arterial pressures preflight in the finishers [15 +/- 3.7 and 8 +/- 1.2 (SE) mmHg, respectively; P < 0.05]. Postflight, finishers and nonfinishers had equally large postural reductions in stroke volume (-47 +/- 3.7 and -48 +/- 3.3 ml, respectively) and increases in heart rate (35 +/- 6.6 and 51 +/- 5.2 beats/min, respectively). Cardiac output during standing was also similar (3.6 +/- 0.4 and 4.1 +/- 0.3 l/min, respectively). However, the finishers had a greater postflight vasoconstrictor response with higher total peripheral resistance during standing (22.3 +/- 1.2 units preflight and 29.4 +/- 2.3 units postflight) than did the nonfinishers (20.1 +/- 1.1 units preflight and 19.9 +/- 1.4 units postflight). We conclude that 1) the primary systemic hemodynamic event, i.e., the postural decrease in stroke volume, was similar in finishers and nonfinishers and 2) the heart rate response and cardiac output during standing were not significantly different, but 3) the postural vasoconstrictor response was significantly greater among the finishers (P < 0.01).

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