Varying the Temperature Around the Scrotum of a Conscious Dog Between 15 °C and 31 °C does not Affect Respiration or Metabolism

1973 ◽  
Vol 51 (3) ◽  
pp. 197-204 ◽  
Author(s):  
J. L. Plewes ◽  
D. B. Jennings
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Respiratory Function ◽  
Perfusion System ◽  
Similar Time ◽  
Conscious Dog ◽  
Scrotal Temperature ◽  
Series Of Experiments ◽  
Temperature Controlled ◽  
Stimulation Of

A jockstrap which contained a temperature-controlled water perfusion system was placed around the scrotum of a resting conscious dog. Two series of experiments (five studies each) were carried out. In one series scrotal perfusion temperature was lowered in steps at 30-min intervals at temperatures of 31, 27, 23, 19, and 15 °C. Another comparable series of experiments was carried out except that the scrotal perfusion temperature was increased in the same steps from 15 to 31 °C. In both experiments there was a fall in hypothalamic and rectal temperatures with time but this was not different from control studies over a similar time in which scrotal perfusion temperature was maintained constant. Warming the scrotal area resulted in an increase in scrotal temperature and cooling the scrotal area resulted in a decrease in scrotal temperature. Despite these changes in local perfusion and scrotal temperatures, there were no significant changes in respiration or oxygen consumption. There was only a small increase in heart rate in the order of 12 beats/min with scrotal warming. It is unlikely that changes in thermal stimulation of the scrotum due to postural variations in resting conscious dogs are primarily responsible for variations in cardio–respiratory function for the conditions of this study.

VARIOUS EFFECTS OF THYROXINE ANALOGUES ON THE HEART AND SERUM CHOLESTEROL IN THE RAT

1960 ◽  
Vol 21 (1) ◽  
pp. 25-32 ◽  
Author(s):  
G. S. BOYD ◽  
M. F. OLIVER
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Serum Cholesterol ◽  
Rate Ratio ◽  
Heart Weight ◽  
Liver Cholesterol ◽  
Response Curves ◽  
Experimental Conditions ◽  
Cholesterol Levels ◽  
Stimulation Of

SUMMARY A series of twelve iodinated thyroxine analogues was studied for thyro-activity in the rat. Each analogue produced antigoitrogenic activity, increased oxygen consumption, heart rate and heart weight, and decreased serum and liver cholesterol levels. A 'serum cholesterol/heart rate ratio' may be computed for these analogues under fixed experimental conditions. While the dose-response curves for different analogues in any of these assays are rarely parallel, it is, nevertheless, clear that under certain experimental conditions some iodothyronines cause a relatively greater depression of cholesterol levels and less stimulation of heart rate than others. Some of the most active in this respect are DT4, DT3, DT2 and T4F.

A mapping study of cardiorespiratory responses to chemical stimulation of the midline medulla oblongata in ventilated and freely breathing rats

2004 ◽  
Vol 287 (2) ◽  
pp. R411-R421 ◽  
Author(s):  
Todd A. Verner ◽  
Ann K. Goodchild ◽  
Paul M. Pilowsky
Keyword(s):  
Heart Rate ◽  
Medulla Oblongata ◽  
Phrenic Nerve ◽  
Respiratory Activity ◽  
Inhibitory Neurons ◽  
Nerve Activity ◽  
Homocysteic Acid ◽  
Anesthetized Rats ◽  
Series Of Experiments ◽  
Stimulation Of

The aim of this study was to examine the cardiorespiratory effects of chemically stimulating neurons in the midline medulla oblongata (MM) of artificially ventilated and freely breathing anesthetized rats. Earlier studies reported that stimulation of the MM elicits increases or decreases in mean arterial pressure (MAP) and phrenic nerve activity, depending on the mode and site of stimulation, anesthetic, and species. In the first series of experiments, rats were anesthetized with urethane, artificially ventilated, paralyzed, and bilaterally vagotomized. The rostrocaudal extent of the MM was mapped by microinjections of dl-homocysteic acid or l-glutamate (both 100 mM, 100 nl), and, in line with previous studies, most injections produced only small responses in MAP, heart rate, and splanchnic sympathetic nerve activity. Increases in respiratory parameters were evoked in caudal regions. However, activation of a discrete region of the MM at the level of the caudal pole of the facial nucleus (CP7) consistently caused a dramatic reduction in phrenic nerve amplitude and/or frequency and, in six rats, produced a prolonged apnea. The second series of experiments was carried out on freely breathing pentobarbitone sodium-anesthetized rats, with a diaphragmatic electromyogram used to monitor respiratory activity. Respiratory activity could again be abolished at CP7 after microinjections of glutamate (100 mM, 50 nl); however, these responses were accompanied by large decreases in MAP and moderate reductions in heart rate. This depression of respiratory activity may be due to activation of propriobulbar inhibitory neurons that project to known respiratory centers in the brain stem.

Aestivation of the African Lungfish Protopterus Aethiopicus: Cardiovascular and Respiratory Functions

1974 ◽  
Vol 61 (1) ◽  
pp. 111-128 ◽  
Author(s):  
R. G. DELANEY ◽  
S. LAHIRI ◽  
A. P. FISHMAN
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Oxygen Consumption ◽  
Respiratory Function ◽  
Control Range ◽  
Arterial Blood ◽  
Arterial Ph ◽  
Sensory Disturbances ◽  
The Mean ◽  
African Lungfish

The present study was undertaken to elicit the temporal sequence of changes in cardiovascular and respiratory function during aestivation. Twelve lungfish (2-6 kg) equipped with ECG electrodes, arterial and buccal cannulae, were studied while aestivating in mud or in artificial cloth-bag nests. The periods of observation ranged from 0.5 to 9.5 months. The mean arterial blood pressure gradually decreased from control values of 20-28 mm Hg to a range of 14-18 mmHg during the first 30 days of aestivation, whereas the heart rate dropped more gradually (22-30 beats/min to 11-16 beats/min in 6o days). Ventilatory frequency increased 2- to 5-fold during the first 30 days of encystment and then returned to the control range (2-10 h) within 45 days. The arterial PCOCO2 increased from control values of 25-30 mm Hg to 45-70 mmHg; arterial pH decreased concomitantly from 7.55-7.60 to 7.40-7.26 after the cocoon was formed. The arterial POO2 increased from the control range of 25-40 to 50-58 mmHg during the first 10 days and then returned to the control range. Therefore, the sequential cardiopulmonary changes during the onset of aestivation are gradual and do not parallel the decline in oxygen consumption. Aestivating lungfish also respond promptly to sensory disturbances and thus do not appear to be in a deep torpor. Aestivation is pictured as a state of dormancy, gradual in onset, and the consequence of a complicated physiological interplay.

Physiological effects of active and passive exercise

1964 ◽  
Vol 19 (6) ◽  
pp. 1212-1214 ◽  
Author(s):  
F. B. Benjamin ◽  
L. Peyser
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Body Temperature ◽  
Heat Production ◽  
Temperature Factor ◽  
Physiological Effects ◽  
Passive Exercise ◽  
Series Of Experiments ◽  
End Tidal

A comparison of the physiological effects of active and passive exercise was accomplished using two methods. In the first series of experiments, the exercise was held constant. In the second method, an attempt to match oxygen consumption was employed. The results, evaluated in view of preceding investigations in the same area, indicate that: 1) Passive exercise inincreases ventilation in excess of the metabolic need. The greater ventilation increases the ventilating equivalent and lowers the end-tidal Pco2, possibly causing respiratory alkalemia. 2) The increase in ventilation accompanying passive exercise does not produce a corresponding increase in heart rate. 3) Passive exercise increases heat production beyond the level indicated by oxygen consumption. These findings support the concept of a temperature factor being involved in the hyperventilation of exercise. ventilation equivalent in exercise; oxygen consumption in exercise; body temperature in exercise Submitted on March 25, 1964

CARDIORESPIRATORY SYSTEM UNDER BICYCLE ERGOMETER TEST IN SKIERS WITH DIFFERENT TRAINING STATUS (KOMI REPUBLIC)

2019 ◽  
pp. 76-84
Author(s):  
Yu.G. Solonin ◽  
T.P. Loginova ◽  
I.O. Garnov ◽  
A.L. Markov ◽  
A.A. Chernykh ◽  
...  
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Komi Republic ◽  
Rate Pressure Product ◽  
Training Status ◽  
Maximum Oxygen Consumption ◽  
Bicycle Ergometry ◽  
Cardiorespiratory System ◽  
Unit Pulse ◽  
Ski Racers

The aim of the study is to examine the impact of training status on ski racers (Komi Republic) at rest and under bicycle ergometry evaluating their cardiorespiratory system parameters. Materials and Methods. The authors examined male ski racers with different training status: 22 first-rank sportsmen, 22 candidates for Master of Sports and 22 Masters of Sports. Athletes underwent bicycle ergometry loads up to refusal. Oxycon Pro system (Germany) was used. Then authors studied the complex of cardiorespiratory parameters, calculating maximum oxygen consumption and unit physiological cost. Results. At rest and under standard physical load (200 W) Masters of Sports demonstrate significantly increased training status among ski racers in such cardiorespiratory system parameters as heart rate, rate pressure product and oxygen pulse. Under standard physical load (200 W) statistically significant differences between first-rank sportsmen and candidates for Master of Sports are detected by heart rate, rate pressure product, respiration rate, respiratory minute volume and oxygen utilization coefficient. Such deviations indicate differences in training status. Under maximum load, the highest training status is found in Masters of Sports: bicycle ergometry load power and duration; unit pulse, pressor and cardiac cost, bulk and unit values of maximum oxygen consumption. Heart rate values, unit pulse and heart-vent cost indicate a high training status in candidates for Master of Sports under load up to refusal, if compared with first-rank sportsmen. Athletes’ organism under load up to refusal works more efficiently than under moderate load (200 W). The training status in ski racers (Komi Republic) is manifested in the saving cardiorespiratory system functions, both at rest and under standard bicycle ergometry, as well as in parameters of unit physiological cost under loads up to refusal and increased values of maximum oxygen consumption. Keywords: ski racers, Komi Republic, training status, bicycle ergometry loads, cardiorespiratory system, maximum oxygen consumption.

Electrical stimulation of the carotid sinus lowers arterial pressure and improves heart rate variability in l-NAME hypertensive conscious rats

2020 ◽  
Vol 43 (10) ◽  
pp. 1057-1067 ◽  
Author(s):  
Gean Domingos-Souza ◽  
Fernanda Machado Santos-Almeida ◽  
César Arruda Meschiari ◽  
Nathanne S. Ferreira ◽  
Camila A. Pereira ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Electrical Stimulation ◽  
Arterial Pressure ◽  
Carotid Sinus ◽  
Conscious Rats ◽  
Stimulation Of

Accuracy of the Heart Rate Index Equation to Assess Oxygen Consumption in Obese Patients

2014 ◽  
Vol 46 ◽  
pp. 169-170
Author(s):  
Roger L. Sacks ◽  
Barry Franklin ◽  
Judy Boura ◽  
James Van Loon
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Obese Patients

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.

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