Respiratory Metabolism During Pregnancy in the Guinea Pig

1957 ◽  
Vol 190 (3) ◽  
pp. 425-428 ◽  
Author(s):  
Richard M. Hoar ◽  
William C. Young
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Guinea Pig ◽  
Metabolic Rate ◽  
Adrenal Cortex ◽  
Guinea Pigs ◽  
Sharp Decrease ◽  
Zona Fasciculata ◽  
Respiratory Metabolism ◽  
Morphological Differences

Oxygen consumption and heart rate during pregnancy were measured in untreated, thyroxin-injected and thyroidectomized guinea pigs given I131. From impregnation until parturition, oxygen consumption increased 7.9% in untreated females. The increase continued until 5 days postpartum when a sharp decrease occurred. The increase is not accounted for by growth of the fetal mass. Comparable increases occurred in thyroxin-injected (16.2%) and thyroidectomized (11.9%) females, although the levels throughout were higher and lower, respectively, than in intact females. Heart rate did not increase. On the contrary, statistically significant decreases occurred in the untreated and thyroxin-injected females. Although the mechanism associated with the increased metabolic rate is not known, the possibility of thyroid participation would seem to be excluded. Involvement of the adrenal cortex is suggested by morphological differences in the cells of the zona fasciculata in pregnant and nonpregnant females and by evidence cited from other studies.

Effect of Acetaldehyde on the Isolated, Non-working Guinea-Pig Heart: Independence of the Coronary Flow Increase from Changes in Heart Rate and Oxygen Consumption

1974 ◽  
Vol 52 (3) ◽  
pp. 602-612 ◽  
Author(s):  
Minh-Hau Nguyen ◽  
L. Gailis
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Guinea Pig ◽  
Gas Phase ◽  
Coronary Flow ◽  
Constant Pressure ◽  
Guinea Pig Heart ◽  
Bicarbonate Buffer

Guinea-pig hearts were perfused at constant pressure with Krehs–Henseleit bicarbonate buffer equilibrated with 95% O2 – 5% CO2. Acetaldehyde at 1 and 5 mM increased coronary flow, oxygen consumption, and heart rate. At 0.2 mM, it increased coronary flow and oxygen consumption only. In the rapidly paced heart, 1 mM acetaldehyde increased coronary flow, but not heart rate or oxygen consumption. Acetaldehyde increased coronary flow and oxygen consumption of the potassium-arrested heart. Acetaldehyde increased all parameters of the hypoxic heart (25% O2 gas phase), but the anoxic heart was not affected (coronary flow was already maximal).Reserpine (in vivo) and catecholamine β blockers (dichloroisoproterenol and propranolol) (in vitro) blocked the heart rate increases and moderated the rise in oxygen consumption. Dichloroisoproterenol plus phentolamine blocked the increases of both heart rate and oxygen consumption. None of the compounds affected the increase of coronary flow produced by acetaldehyde. Epinephrine, norepinephrine, and tyramine increased the heart rate and oxygen consumption, but not the coronary flow. Theophylline increased all three parameters. Neither tranylcypromine nor atropine modified the acetaldehyde effect. We conclude that the increase in heart rate is mediated by catecholamine β receptors. The increase in coronary flow is independent of the increase in heart rate or oxygen consumption and is not mediated by catecholamines.

Effects of restraint on oxygen consumption of the cold exposed guinea pig

1959 ◽  
Vol 14 (1) ◽  
pp. 46-48 ◽  
Author(s):  
R. G. Bartlett
Keyword(s):  
Oxygen Consumption ◽  
Data Collection ◽  
Guinea Pig ◽  
Heat Loss ◽  
Heat Production ◽  
Guinea Pigs ◽  
Muscular Activity ◽  
Physiological Changes

The oxygen consumption of cold exposed, restrained guinea pigs is significantly greater than that of cold exposed, nonrestrained controls. Similar observations have been made for the rat ( Canad. J. Biochem. & Physiol. 33:654, 1955). These data strongly suggest that heat production is greater in the restrained animal than in the nonrestrained control. The hypothermia, then, accompanying restraint in the cold cannot be laid to a decreased muscular activity (muscular activity is actually increased) and a consequently lessened heat production, as suggested by some ( J. Appl. Physiol. 12:214, 1958). It must be due, as demonstrated for the rat ( Am. J. Physiol. 193:557, 1958), to an increased rate of heat loss. The marked physiological changes accompanying restraint should serve as a warning to the investigator who uses restraint for convenience in data collection. Submitted on July 11, 1958

Comparison of the response of muskrat, rabbit, and guinea pig heart muscle to hypoxia

1982 ◽  
Vol 243 (3) ◽  
pp. R245-R250
Author(s):  
T. McKean ◽  
R. Landon
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Guinea Pig ◽  
Coronary Blood Flow ◽  
Guinea Pigs ◽  
Cell Damage ◽  
Isolated Heart ◽  
Ether Anesthesia ◽  
Peak Tension ◽  
Time To Peak

Papillary muscles were removed from anesthetized muskrats and rabbits and mounted in a muscle chamber maintained at 29 degrees C. Muscles were stimulated at a rate of 12/min and subjected to 30 min of hypoxia followed by 30 min of reoxygenation. Peak tension in muskrats declined less than peak tension in rabbits during oxygen deprivation. During reoxygenation, peak tension in muskrats rapidly returned to control levels and then exceeded control, whereas peak tension in rabbits never recovered. Time to peak tension was largely unaffected in muskrats during hypoxia and decreased in rabbits. During reoxygenation, time to peak tension increased in muskrats and returned to control in rabbits. Hearts from muskrats and guinea pigs were removed under ether anesthesia and perfused retrograde with a physiological saline solution. Developed tension, heart rate, coronary blood flow, and lactate dehydrogenase (LDH) output were monitored. During 30 min of hypoxia, muskrat hearts developed a profound bradycardia compared to guinea pigs. Coronary flow increased in both species but less so in muskrats. Guinea pig hearts developed contracture whereas muskrat hearts relaxed. During reoxygenation heart rate and coronary blood flow returned toward normal but cells released large amounts of LDH, indicating cell damage. It is concluded that the isolated heart of the muskrat, a diving mammal, is better able to deal with hypoxia than the heart of the nondividing guinea pig and rabbit.

Cardiovascular and metabolic responses during burn shock in the guinea pig

1976 ◽  
Vol 231 (3) ◽  
pp. 892-897 ◽  
Author(s):  
RR Wolfe ◽  
HI Miller
Keyword(s):  
Cardiac Output ◽  
Oxygen Consumption ◽  
Guinea Pig ◽  
Core Temperature ◽  
Plasma Glucose ◽  
Guinea Pigs ◽  
Tissue Perfusion ◽  
Metabolic Responses ◽  
Burn Shock ◽  
Lactate Levels

The hemodynamic and metabolic responses of fatally burned, nonfatally burned, and unburned control guinea pigs were compared. The burns were induced in temporarily anesthetized animals by immersion to either the xyphoid process (70% fatal) or the midabdomen (100%survival) in boiling water for 3 s. Although cardiac output was reduced in all animals postburn, the survivors (MAG) has higher cardiac outputs at lower arterial pressures than the nonsurvivors (XPN). The postburn lactate levels in the XPN were higher than in the MAG, and the postburn values for pH, oxygen consumption, and core temperature were lower in the XPN. In each group, hyperglycemia was evident for 8 h postburn and terminal plasma glucose concentrations were usually elevated or similar to the prevalue. It was concluded that fatal and nonfatal burn shock were distinguished primarily by differences in tissue perfusion.

ÜBER DEN EINFLUSS VON OESTRADIOL AUF DIE RESTITUTIONSPHASE DER NEBENNIERENRINDE NACH LANGFRISTIGER CORTISONVORBEHANDLUNG

1962 ◽  
Vol 40 (3) ◽  
pp. 410-420 ◽  
Author(s):  
M. Herrmann ◽  
G. Winkler
Keyword(s):  
Adrenal Cortex ◽  
Guinea Pigs ◽  
Diphtheria Toxin ◽  
Zona Fasciculata ◽  
Tissue Lesion ◽  
Haemorrhagic Necrosis

ABSTRACT Male guinea pigs were simultaneously treated with cortisone and oestradiol-dipropionate. Observations were made on the nuclear volumes of the cells of the zona fasciculata of the adrenal cortex, the urinary 17-hydroxycorticoids and the haemorrhagic necrosis after intoxication with diphtheria-toxin. The comparatively long restitution phase of the adrenals following the long-term pretreatment with cortisone only may be considerably reduced by application of oestradioldipropionate, which is shown by the following results: the nuclear volumes of fasciculata cells of the adrenal cortex stay normal or show higher values after termination of the pretreatment. Haemorrhagic necrosis in the adrenal cortex after intoxication with diphtheria-toxin is observed on the 2nd day after long-term pretreatment with cortisone and oestradioldipropionate. In animals treated with cortisone only this tissue lesion is observed at first on the 8th day after termination of the pretreatment. The excretion of 17-hydroxycorticoids does not correspond with this accelerated reaction of the adrenal cortex.

Ergonomic Considerations of Fin Size for Working Divers

1982 ◽  
Vol 26 (6) ◽  
pp. 525-529 ◽  
Author(s):  
I. B. Mekjavic ◽  
P. A. Rowe ◽  
J. B. Morrison
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Metabolic Rate ◽  
Cardiovascular System ◽  
Surface Area ◽  
Minute Ventilation ◽  
Metabolic Cost ◽  
Breathing Frequency ◽  
Work Period ◽  
Ventilatory Volume

Four divers conducted two identical work protocols, consisting of swimming against a graded resistance on an underwater ergometer at a depth of ten feet. In one protocol the divers used fins each having a surface area of 540 cm2 and in the second protocol they used fins whose surface area was 940 cm2. Oxygen consumption, heart rate, ventilation, breathing frequency and kick rate were monitored throughout the twenty minute work period. The 540 cm2 fins demanded a siqnificantly higher metabolic rate than the 940 cm2 fins (50.85 ± 1.54 compared to 46.99 ± 1.52 ml.min.-1.kg-1). The smaller fins also elicited higher heart rates (171.8 ± 4.3 min.-1) than the larger fins (142.5 ± 8.7 min.-1) and induced a higher kicking frequency than was required with the larger fins (43 ± 4 min.-1 and 32 ± 1 min.-1 respectively). Ventilatory volume at the end of the final workload was 128.6 ± 7 1/min. with small fins and 111.1 ± 6.5 1/min. with large fins. These data suggest that the larger fins are more economical in terms of minute ventilation and metabolic cost and are less demanding on the cardiovascular system. Subjectively, the larger fins were perceived as less fatiguing than the smaller fins.

THE EFFECT OF OESTRONE ON THE MAMMARY GLAND OF ADRENALECTOMIZED GUINEA-PIGS

1957 ◽  
Vol 16 (2) ◽  
pp. 227-NP ◽  
Author(s):  
E. O. HÖHN
Keyword(s):  
Mammary Gland ◽  
Guinea Pig ◽  
Adrenal Cortex ◽  
Guinea Pigs ◽  
Growth Response ◽  
Alcoholic Solution ◽  
Survival Period ◽  
Alveolar Development ◽  
Average Survival

SUMMARY In the guinea-pig progesterone is not required for alveolar development of the mammary gland. In order to test the hypothesis that this can be accounted for by endogenous progesterone produced by the adrenal cortex in this species, the growth response of the mammary gland to oestrone of adrenalectomized castrated male guinea-pigs has been studied. Oestrone applied to the nipples as an alcoholic solution in doses of 15 μg/day for 14 days resulted in the formation of clusters of mammary alveoli in animals subjected merely to castration. In eleven castrated and adrenalectomized animals which survived oestrone treatment for periods of 11–28 days only duct proliferation with occasional formation of isolated alveoli was observed. Nipple growth in response to oestrone, as indicated by changes in nipple length, was much the same in both groups. Administration of oestrone to adrenalectomized animals was found to be toxic. The average survival of oestrone-treated, adrenalectomized castrated animals was only 4 days, compared with an average survival period of 16·6 days in similar animals not treated with oestrone.

Respiratory Metabolism of Pumpkinseed (Lepomis gibbosus) in Relation to Swimming Speed

1965 ◽  
Vol 22 (2) ◽  
pp. 405-409 ◽  
Author(s):  
J. R. Brett ◽  
D. B. Sutherland
Keyword(s):  
Oxygen Consumption ◽  
Metabolic Rate ◽  
Swimming Speed ◽  
Aggressive Behaviour ◽  
Lepomis Gibbosus ◽  
Respiratory Metabolism ◽  
Metabolic Rates

By use of a "tunnel" respirometer the relation between oxygen consumption (Y, mg O2/kg/hr) and swimming speed (X, body lengths/sec) for 45-g pumpkinseed at 20 °C was found to follow the equation log10Y = 1.65 4 + 0.31 X. Standard and active metabolic rates were 45 ± 6.6 and 408 ± 39 mg O2/kg/hr, respectively. Maximum 60-min sustained swimming speeds averaged 3.01 ± 0.27 lengths/sec.At low velocities, with more than one fish present, elevation of the metabolic rate occurred from aggressive behaviour, reaching one-half the active rate.

Left ventricular heat production during induced tachycardia in the intact dog

1965 ◽  
Vol 209 (1) ◽  
pp. 33-36 ◽  
Author(s):  
Skoda Afonso ◽  
David H. McKenna ◽  
George S. O'Brien ◽  
George G. Rowe ◽  
Charles W. Crumpton
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Oxygen Consumption ◽  
Metabolic Rate ◽  
Coronary Blood Flow ◽  
Heat Production ◽  
Myocardial Oxygen Consumption ◽  
Left Ventricular ◽  
Metabolic Parameters ◽  
Heat Control

It is well established that heart rate is a determinant of myocardial oxygen consumption. However, it has not been demonstrated that the increase of oxygen consumption at faster rates actually represents loss of energy, degraded as heat. Control measurements of systemic and coronary hemodynamic and metabolic parameters and left ventricular heat production (measured by a recently reported method) were obtained in 10 dogs. Tachycardia was then induced electrically and the same parameters redetermined. Significant increases occurred in coronary blood flow, cardiac metabolic rate of oxygen, and left ventricular heat production. The elevated myocardial oxygen consumption at higher rates is associated with increased heat production.

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