Physiological variability in neonatal armadillo quadruplets: within- and between-litter differences

2000 ◽  
Vol 203 (11) ◽  
pp. 1733-1740 ◽  
Author(s):  
B. Bagatto ◽  
D.A. Crossley ◽  
W.W. Burggren
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Ventilation Rate ◽  
Dasypus Novemcinctus ◽  
Genetic Components ◽  
Physiological Variability ◽  
In Captivity ◽  
Flow Through ◽  
Physiological Characters

The role of genetics on neonatal physiological variability was examined in the nine-banded armadillo (Dasypus novemcinctus). Since armadillos give birth to only monozygous quadruplets, the genetic variation within litters is essentially zero. Quadruplets born in captivity were isolated and weighed within 8 h of birth. Oxygen consumption (V.(O2)) was measured in resting neonates by flow-through respirometry, heart rate obtained from an electrocardiogram and ventilation was measured by impedance techniques. Following the measurements, neonates were returned to the mother. Measurements were repeated at 4 and 8 days after birth. Mean heart rate significantly increased from 132 beats min(−1) on the day of birth to 169 beats min(−1) on day 8. Mean ventilation rate significantly decreased from 81 breaths min(−1) on the day of birth to 54 breaths min(−1) on day 8. During this same developmental period, mean mass significantly increased from 100 g to 129 g, and mean mass-specific oxygen consumption significantly decreased from 32.2 ml O(2)kg(−1)min(−1) to 28.6 ml O(2)kg(−1) min(−1). For all variables measured, within-litter variability was always significantly less than between-litter variability, confirming a ‘sibling effect’ that we attribute to the genetic components determining physiological characters.

scholarly journals 582 THE ROLE OF HYPERVOLEMIA AND STROKE VOLUME IN THE HEART RATE AND OXYGEN CONSUMPTION RELATIONSHIP FOLLOWING INTENSE TRAINING

1993 ◽  
Vol 25 (Supplement) ◽  
pp. S104
Author(s):  
R. S. Richardson ◽  
D. Verestraete ◽  
A. Hochstein ◽  
W. Schultz ◽  
S. C. Johnson ◽  
...  
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Stroke Volume ◽  
Intense Training

Some physiological responses of man to workload and environment

1961 ◽  
Vol 16 (3) ◽  
pp. 413-420 ◽  
Author(s):  
C. W. Suggs ◽  
W. E. Splinter
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Relative Humidity ◽  
Oxygen Consumption Rate ◽  
Consumption Rate ◽  
Mechanical Efficiency ◽  
Prediction Equation ◽  
Ventilation Rate ◽  
Three Dimensions ◽  
High Workload

The heart rate, ventilation rate, oxygen consumption rate, and mechanical efficiency responses of a subject to a series of temperatures, relative humidities, and workloads were observed. A quadratic prediction equation of each of the responses as steady-state functions of the independent variables was derived. Each of the equations represents a four-dimensional hypersurface. For the heart rate, ventilation rate, and oxygen consumption rate the hypersurfaces are quite similar, the responses increasing rapidly with respect to workload and about one-third as rapidly with respect to temperature. The effect of relative humidity was present primarily as interactions. Mechanical efficiency was represented by a more complex hypersurface. In three dimensions, with relative humidity as a parameter, the response was a saddle-shaped surface with the highest efficiency at a condition of low temperature, high workload. At constant environment, the heart rate responses of 19 subjects to workloads was observed and found to be linear with a normal distribution of slopes. Submitted on May 2, 1960

Neuropeptide Y and coronary vasoconstriction: role of thromboxane A2

1992 ◽  
Vol 263 (4) ◽  
pp. H1045-H1053
Author(s):  
S. E. Martin ◽  
J. T. Kuvin ◽  
S. Offenbacher ◽  
B. M. Odle ◽  
R. E. Patterson
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Oxygen Consumption ◽  
Neuropeptide Y ◽  
Coronary Blood Flow ◽  
Myocardial Oxygen Consumption ◽  
Thromboxane A2 ◽  
Coronary Resistance ◽  
Txa2 Receptor

We previously reported that coronary constriction following neuropeptide Y (NPY) was alleviated by cyclooxygenase blockade. To determine the role of thromboxane A2 (TxA2), anesthetized dogs received two paired doses of NPY given 2 h apart. Nine control dogs received NPY alone. Nine test dogs received one of three TxA2 receptor antagonists given between the doses of NPY. Also, five dogs received NPY during which prostaglandins were measured. In controls, NPY decreased coronary blood flow and increased aortic pressure; coronary resistance was increased significantly. Heart rate fell, and myocardial oxygen consumption was unchanged. Thromboxane receptor blockers significantly relieved the coronary constrictor effect of NPY. The reduction in coronary blood flow was blunted, while heart rate, first derivative of left ventricular pressure, and myocardial oxygen consumption were unchanged. Alleviation by TxA2 receptor blockade paralleled that reported for cyclooxygenase inhibitors. Also, significant increases in coronary venous TxA2 were seen at the time of maximal increases in coronary resistance, while prostacyclin was unchanged. In summary, TxA2 appears to mediate part of the coronary constrictor effect of NPY.

Acute Cardio-respiratory responses of Spangled Perch, Leiopotherapon unicolor (Gunther 1859), to Sublethal concentrations of Zinc, Temephos and 2,4-D

1988 ◽  
Vol 39 (6) ◽  
pp. 767 ◽  
Author(s):  
PC Gehrke
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Gas Exchange ◽  
Respiratory System ◽  
Ventilation Rate ◽  
Cholinesterase Inhibition ◽  
Gill Epithelium ◽  
Arterial Blood ◽  
Sublethal Concentrations ◽  
Respiratory Responses

Spangled perch, Leiopotherapon unicolor, were exposed to concentrations of 5.0, 10 or 20 mg 1-1 zinc, 0.1, 1.0 or 10 mg 1-1 temephos or 0.1, 1.0 or 10 mg 1-1 2,4-D at 25�C for 2 h, during which time ventilation rate, heart rate and oxygen consumption were continuously monitored. Fish exposed to 10 and 20 mg 1-1 zinc demonstrated a significant increase in ventilation rate; those exposed to 20 mg 1-1 also developed a significant bradycardia. Exposure to 10 mg 1-1 temephos caused an immediate reduction in ventilation rate and oxygen consumption, and also reduced heart rate during the second hour of exposure. Fish exposed to 10 mg 1-1 temephos died within 12 h. Responses of fish to 2,4-D gave no indication of toxic effects on the cardio-respiratory system. Cardio-respiratory responses to zinc are attributed to damage caused to the gill epithelium, which results in impaired gas exchange and lowered oxygen tension in arterial blood. Effects of exposure to temephos correspond to cholinesterase inhibition in nerves supplying the respiratory musculature and the heart.

Effects of self-contained breathing apparatus on ventricular function during strenuous exercise

2009 ◽  
Vol 106 (2) ◽  
pp. 395-402 ◽  
Author(s):  
Michael D. Nelson ◽  
Mark J. Haykowsky ◽  
Jonathan R. Mayne ◽  
Richard L. Jones ◽  
Stewart R. Petersen
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Oxygen Consumption ◽  
Systolic Blood Pressure ◽  
Ventricular Function ◽  
Esophageal Pressure ◽  
Ventilation Rate ◽  
Strenuous Exercise ◽  
Protective Equipment ◽  
Breathing Apparatus

The purpose of this study was to investigate left-ventricular function during strenuous exercise with the self-contained breathing apparatus (SCBA). With the use of two-dimensional echocardiography, images of the left ventricle (LV) were acquired during sustained exercise (3 × 10 min) under two conditions: 1) SCBA, or 2) low resistance breathing valve. Twenty healthy men volunteered for the study, and in each condition subjects wore fire protective equipment. Heart rate, systolic blood pressure, cavity areas during systole and diastole (ESCA and EDCA, respectively), esophageal pressure, ventilation rate, oxygen consumption, perceived physical, thermal and respiratory distress, and core temperature were measured at regular intervals. Urine specific gravity (<1.020 g/ml) and hematological variables were used to infer hydration status. All subjects began both trials in a euhydrated state. No differences were found between conditions for heart rate, systolic blood pressure, ventilation rate, oxygen consumption, perceived distress, or any hematological variables. Peak expiratory esophageal pressure was always higher ( P < 0.05), while EDCA and stroke area (SA) were significantly lower ( P < 0.05) with the SCBA. ESCA, end-systolic transmural pressure (ESTMP), and LV contractility (ESTMP/ESCA) were similar between conditions. Sustained exercise with fire protective equipment resulted in significant reductions in EDCA, ESCA, and SA from the start of exercise, which was associated with a 6.3 ± 0.8% reduction in plasma volume, an increase in core temperature (37.0 ± 0.4 to 38.8 ± 0.3°C), and a significant increase in heart rate (146.9 ± 2.1 to 181.7 ± 2.4 beats/min) throughout exercise. The results from this study support research by others showing that increased intrathoracic pressure reduces LV preload (EDCA); however, the novelty of the present study is that when venous return is compromised by sustained exercise and heat stress, SA cannot be maintained.

Role of the Thyroid in Metabolic Response to Low Temperature

1956 ◽  
Vol 188 (1) ◽  
pp. 40-44 ◽  
Author(s):  
A. C. L. Hsieh ◽  
L. D. Carlson
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Low Temperature ◽  
Metabolic Response ◽  
Muscular Activity ◽  
Half Time ◽  
High Metabolic Rate ◽  
Cold Adapted ◽  
Exposure To Cold

Cold-adapted rats, kept at 5°C, and warm-adapted rats, kept at 28°C, were curarized and oxygen consumption; heart rate; muscular activity; rectal, foot and room temperatures recorded during a period at 30°C and during exposure to cold. The experiments were performed before and at varying intervals after thyroidectomy. Oxygen consumption measured at 30°C reached a minimum 8 days after thyroidectomy in the rats kept at 5°C and 12 days after thyroidectomy in the rats kept at 28°C. The half-time for the decline was twice as long for the rats kept at 28°C, indicating that thyroxin stores were being utilized twice as fast by the rats kept at 5°C. Upon exposure to cold the rats responded by an increase in oxygen consumption. Since the response persisted after thyroxin stores had been depleted it is concluded that the metabolic response to cold is not directly dependent upon the amount of circulating thyroxin. Rats kept at 5°C reduced their food intake and lost weight following thyroidectomy, but maintained a high metabolic rate. The significance of these findings are discussed.

Role of autonomics in the initiation of electromechanical dissociation

1981 ◽  
Vol 241 (3) ◽  
pp. R213-R216
Author(s):  
D. R. Kostreva ◽  
A. Castaner ◽  
J. P. Kampine
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Cardiac Tamponade ◽  
Early Onset ◽  
Increase Heart Rate ◽  
Apparent Effect ◽  
Cardiac Work ◽  
Double Product ◽  
Bilateral Vagotomy

The onset of electromechanical dissociation during acute cardiac tamponade in mongrel dogs is significantly prolonged by either surgical or pharmacologic sympathectomy. Bilateral vagotomy does not have any apparent effect on the initiation of electromechanical dissociation. Pretreatment with isoproterenol just prior to tamponade does not significantly increase heart rate or the double product. Cardiopulmonary sympathetic efferent stimulation significantly decreases the time to the onset of electromechanical dissociation by increasing the heart rate and double product. The early onset of electromechanical dissociation appears to be related to cardiac work and oxygen consumption.

Haemolymph flow distribution, cardiac performance and ventilation during moderate walking activity in Cancer magister (Dana) (Decapoda, Crustacea)

1996 ◽  
Vol 199 (3) ◽  
pp. 627-633 ◽  
Author(s):  
B Wachter ◽  
B Mcmahon
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Relative Proportion ◽  
Flow Distribution ◽  
Ventilation Rate ◽  
Arterial System ◽  
Cancer Magister ◽  
Walking Activity ◽  
Flow Through

Adult male Cancer magister (Dana) were equipped with pulsed-Doppler flowmeters and pressure transducers for simultaneous measurement of heart and ventilation frequencies, haemolymph flow through each of the major arterial systems and cardiac output and for calculation of stroke volume. Each variable was measured at rest and during two consecutive periods of moderate treadmill walking activity and recovery. During activity, haemolymph flow through the sternal and anterolateral arteries increased, while flow through the hepatic arterial system decreased. This resulted in a redistribution of haemolymph flow in which a proportion of cardiac output was shifted from the anterior, posterior and hepatic arterial systems to the sternal arterial system. The relative proportion of the cardiac output flowing through the anterolateral artery remained constant. This indicated that oxygen supply was shifted away from the digestive system to the muscles of the walking legs and the respiratory system. Cardiac output, heart rate and stroke volume all increased in response to activity. The increase in cardiac output is the result of a large increase in stroke volume and a small increase in heart rate. A doubling of ventilation rate also occurred during activity. Both the circulatory and ventilatory systems were restored to pre-activity values by 60 min of recovery.

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