Effect of O2 and CO2 in N2, He, and SF6 on chick embryo blood pressure and heart rate

1981 ◽  
Vol 51 (4) ◽  
pp. 1017-1022 ◽  
Author(s):  
H. Tazawa
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Gas Exchange ◽  
Chick Embryo ◽  
Sulfur Hexafluoride ◽  
Inert Gases ◽  
Maximum Pressure ◽  
Chick Embryos ◽  
Respiratory Gas Exchange ◽  
Made In

Arterial pressure of chick embryos was measured electromanometrically to investigate the effect of altered gaseous environments on blood pressure (BP) and heart rate (HR). The experiments were made in eggs incubated for 14–16 days at 38 degrees C without impeding the diffusive respiratory gas exchange through the shell and chorioallantois. In air, the HR was counted 260–270 beats/min and the BP increased from 14/7 Torr at day 14 to 21/12 Torr at day 16. Both the BP and HR decreased with hypoxia, whereas hyperoxia affected a slight increase in BP and little change in HR. Hypercapnia decreased the HR and tended to enhance a systolic maximum pressure. The effect of hypoxia was augmented markedly in the presence of hypercapnia and vice versa. When N2 was replaced with helium (He), the effect of hypoxia was mitigated significantly. On the contrary, replacement of N2 with sulfur hexafluoride (SF6) augmented the effect of hypoxia. Because the respiratory gas exchange of the egg takes place by diffusion through the shell and chorioallantoic capillaries, the effect of He and SF6 atmospheres on BP and HR is attributed to an altered diffusivity of O2 and CO2 in these inert gases.

Measurement of blood pressure of chick embryo with an implanted needle catheter

1981 ◽  
Vol 51 (4) ◽  
pp. 1023-1026 ◽  
Author(s):  
H. Tazawa
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Gas Exchange ◽  
Chick Embryo ◽  
Venous Pressure ◽  
Blood Gases ◽  
Hypodermic Needle ◽  
Chick Embryos ◽  
Polyethylene Tube ◽  
Physiological Values

A catheter, consisting of a hypodermic needle and polyethylene tube, was implanted in the allantoic artery and/or vein of chick embryos ranging in incubation ages from 13 to 17 days. The procedure was performed through a small hole opened in the shell (less than 1 cm2). The hole was covered after implantation of the catheter, ensuring the adequate gas exchange by the chorioallantois and physiological values of blood gases. Blood pressure was measured with an electromanometric transducer. The arterial pressure lacked a dicrotic elevation. Both the systolic and diastolic pressures increased markedly with days of incubation, but the heart rate showed no significant change. The venous pressure was pulsatile in some eggs, and the pulsations became prominent after administration of epinephrine.

Evidence that blood pressure controls heart rate in the chick embryo prior to neural control

Development ◽  
1976 ◽  
Vol 36 (3) ◽  
pp. 685-695
Author(s):  
G. M. Rajala ◽  
J. H. Kalbfleisch ◽  
S. Kaplan
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Chick Embryo ◽  
Heart Muscle ◽  
Neural Control ◽  
Isolated Heart ◽  
Fluid Pressure ◽  
Chick Embryos ◽  
Isolated Hearts ◽  
Increased Pressure

Blood pressure increases will increase heart rate in intact chick embryos, prior to tne development of neural control. Similarly, in surgically isolated hearts, increases in intraventricular fluid pressure will increase the rate of beat. However, fluid pressure applied equally to both interior and exterior surfaces of the isolated heart does not result in increased heart rate. Therefore, we conclude that the increased pressure stretches the heart muscle and that this stretch stimulates the increased heart rate. While heart rate is clearly influenced by blood pressure, the reverse is not true. Propranolol reduces the heart rate to about half normal in intact embryos but does not significantly alter the blood pressure.

scholarly journals Coca chewing for exercise: hormonal and metabolic responses of nonhabitual chewers

1996 ◽  
Vol 81 (5) ◽  
pp. 1901-1907 ◽  
Author(s):  
Roland Favier ◽  
Esperanza Caceres ◽  
Laurent Guillon ◽  
Brigitte Sempore ◽  
Michel Sauvain ◽  
...  
Keyword(s):  
Heart Rate ◽  
Gas Exchange ◽  
Oxygen Uptake ◽  
Metabolic Responses ◽  
Physiological Data ◽  
Respiratory Gas Exchange ◽  
Gum Chewing ◽  
Arterial Blood ◽  
Before And After ◽  
Exercise Induced

Favier, Roland, Esperanza Caceres, Laurent Guillon, Brigitte Sempore, Michel Sauvain, Harry Koubi, and Hilde Spielvogel. Coca chewing for exercise: hormonal and metabolic responses of nonhabitual chewers. J. Appl. Physiol. 81(5): 1901–1907, 1996.—To determine the effects of acute coca use on the hormonal and metabolic responses to exercise, 12 healthy nonhabitual coca users were submitted twice to steady-state exercise (∼75% maximal O2 uptake). On one occasion, they were asked to chew 15 g of coca leaves 1 h before exercise, whereas on the other occasion, exercise was performed after 1 h of chewing a sugar-free chewing gum. Plasma epinephrine, norepinephrine, insulin, glucagon, and metabolites (glucose, lactate, glycerol, and free fatty acids) were determined at rest before and after coca chewing and during the 5th, 15th, 30th, and 60th min of exercise. Simultaneously to these determinations, cardiorespiratory variables (heart rate, mean arterial blood pressure, oxygen uptake, and respiratory gas exchange ratio) were also measured. At rest, coca chewing had no effect on plasma hormonal and metabolic levels except for a significantly reduced insulin concentration. During exercise, the oxygen uptake, heart rate, and respiratory gas exchange ratio were significantly increased in the coca-chewing trial compared with the control (gum-chewing) test. The exercise-induced drop in plasma glucose and insulin was prevented by prior coca chewing. These results contrast with previous data obtained in chronic coca users who display during prolonged submaximal exercise an exaggerated plasma sympathetic response, an enhanced availability and utilization of fat (R. Favier, E. Caceres, H. Koubi, B. Sempore, M. Sauvain, and H. Spielvogel. J. Appl. Physiol. 80: 650–655, 1996). We conclude that, whereas coca chewing might affect glucose homeostasis during exercise, none of the physiological data provided by this study would suggest that acute coca chewing in nonhabitual users could enhance tolerance to exercise.

scholarly journals FLUORESCEIN CIRCULATION TIME AS A PROGNOSTIC SIGN IN EXPERIMENTAL TRAUMATIC SHOCK

1946 ◽  
Vol 84 (6) ◽  
pp. 549-558 ◽  
Author(s):  
S. C. Wang ◽  
E. E. Painter ◽  
R. R. Overman
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Vascular System ◽  
Peripheral Circulation ◽  
Traumatic Shock ◽  
Systemic Circulation ◽  
The Other ◽  
Circulation Time ◽  
Peripheral Vascular ◽  
Made In

Repeated determinations of the circulation time by the fluorescein method were made in normal and shocked dogs. In normal animals the circulation time ranges from 9 to 16 seconds with an average of 12.6 seconds. In traumatic shock the circulation time is invariably prolonged. For prognosis in the traumatized animal two determinations of fluorescein circulation time separated by an interval of 1 hour are essential. If the second circulation time is longer than the first and both are over 30 seconds, the animal will not survive without therapy. On the other hand, if the second circulation time is below 25 seconds or is considerably shorter than the first, the prognosis is good. In many of these experiments the change in circulation time appeared to be the earliest index of eventual recovery or death. It gave a clue to the fate of the animal when no decisive judgment could be made from the blood pressure and heart rate. In three dogs the cyanide and fluorescein circulation times were compared during shock. It was found that the cyanide circulation time, though increased in shock, remained at a fairly constant value while over the same period the fluorescein circulation time showed progressive changes. This discrepancy between the cyanide and fluorescein methods may be explained by the fact that the former does not include the minute peripheral systemic circulation. Since the study of shock is concerned with tissue anoxia and is primarily a phenomenon of the failure of the peripheral circulation, it is important to choose procedures such as the fluorescein method as a measure of the condition of the peripheral vascular system.

Hemodynamics in awake rabbits during hyperbaric helium-oxygen exposure

1980 ◽  
Vol 48 (2) ◽  
pp. 281-283 ◽  
Author(s):  
L. E. Boerboom ◽  
J. N. Boelkins
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Cardiac Output ◽  
Cardiovascular System ◽  
Systemic Vascular Resistance ◽  
Elevated Pressure ◽  
Inert Gases ◽  
Gas Mixture ◽  
Organ Blood Flow

Although man is being exposed to hyperbaric environments more frequently, the effects of these environments and the inert gases used are not clearly defined. We therefore designed an experiment to examine both the effects of helium and elevated pressure on the cardiovascular system in conscious rabbits exposed to normoxic levels of a helium-oxygen (He-O2) gas mixture at 1 and 11 atmospheres absolute (ATA) for 2 h. Variables studied included heart rate, blood pressure, cardiac output, systemic vascular resistance, organ blood flow, and resistance to flow. The only change observed was a decrease in heart rate from a control of 284 +/- 7 (mean +/- SE) to 246 +/- 12 beats/min after 2 h of breathing He-O2 at 1 ATA. We therefore conclude that the cardiovascular system is not adversely affected by helium or elevated pressure as used in this experiment.

Stimulatory and persistent effect of acute hyperoxia on respiratory gas exchange of the chick embryo

1985 ◽  
Vol 62 (2) ◽  
pp. 217-230 ◽  
Author(s):  
Michael K. Stock ◽  
Mary Ann Asson-Batres ◽  
James Metcalfe
Keyword(s):  
Gas Exchange ◽  
Chick Embryo ◽  
Respiratory Gas Exchange ◽  
Persistent Effect
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