Effects of autonomic blockade on pulmonary and systemic circulation before and after birth

Vaughn, D; Kirschbaum, Thomas H.; Bersentes, T; Assali, N.S.

doi:10.1152/ajplegacy.1967.212.2.436

Cited by 15 publications

(10 citation statements)

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“…17 The autonomic nervous system does not seem to play a significant role in the pressure increase since complete ganglionic blockade prior to umbilical cord interruption and onset of respiration did not diminish the magnitude of the changes in the neonatal systemic pressure. 4 Our present data, however, show that on the basis of the arterial pressure response to autonomic antagonists, the systemic circulation of the newborn Iamb is under a neurohumoral control, the magnitude of which decreases progressively with neonatal growth. During the 1st week of neonatal life the systemic hypotension that followed ganglionic blockade was of the same magnitude as that observed in the full-term fetus.…”

Section: The Resting Systemic Arterial and Pulmonary Arterial Pressurcontrasting

confidence: 53%

“…4, APRIL 1977 selected for assessing a given autonomic activity was administered through the jugular vein in the selected doses listed in table 1; all agents except trimethaphan were administered as single bolus intravenous injections; trimethaphan was given by constant infusion as previously. [1][2][3][4] (3) A recovery period until all parameters had returned to control values. During the testing and recovery periods, phasic and integrated pressure signals were recorded continuously on an Offner Dynograph; heart rate was obtained from the pulsatile pressure signal through a cardiotachometer; blood respiratory gases and pH were analyzed at frequent intervals.…”

Section: Methodsmentioning

confidence: 99%

“…1-3 - 4 For statistical treatment of the data each animal was used as its own control. The response to a given agent and the percentage changes were related to the average of all the readings obtained during the 30-to 40-minute control period prior to each test.…”

Section: Methodsmentioning

confidence: 99%

“…4 ' 5t 8 - l7 We have previously demonstrated in the experimental animal and by mathematical simulation that the arterial pressure rise is related to (1) elimination of the low resistance system of the placental vascular bed, and (2) closure of the various vascular shunts. 17 The autonomic nervous system does not seem to play a significant role in the pressure increase since complete ganglionic blockade prior to umbilical cord interruption and onset of respiration did not diminish the magnitude of the changes in the neonatal systemic pressure.…”

Section: The Resting Systemic Arterial and Pulmonary Arterial Pressurmentioning

confidence: 99%

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Autonomic control of cardiovascular functions during neonatal development and in adult sheep.

Woods¹,

Dandavino²,

Murayama³

et al. 1977

Circulation Research

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SUMMARY We studied the autonomic control of resting heart rate and of systemic and pulmonary vascular blood pressures (BP) in chronically instrumented neonatal lambs 1-8 weeks of age. The maximum response to ganglionic blockade and sympathetic and parasympathetic antagonists was taken as an index of the magnitude of the total neural, adrenergic, and cholinergic tones. The reactivity of the circulatory parameters to adrenergic and cholinergic agonists also was investigated. All findings were compared with those in adult nonpregnant sheep studied concomitantly and with data previously obtained from term fetal lambs. The results of our studies show: (1) resting heart rate declines spontaneously throughout the 8 weeks of neonatal life approaching that of adult sheep; (2) the progressive bradycardia is not related to changes in the parasympathetic or sympathetic tone; (3) resting systemic BP is under strong neurohumoral control during the first two to three weeks of neonatal life; the control decreases progressively, becoming similar to that of adult sheep; (4) resting pulmonary artery pressure of neonatal and adult sheep has no neurohumoral control; (5) the systemic BP response of the neonate to autonomic agonists is greater than that of the term fetus and is similar to that of the adult; (6) in neonatal and adult sheep, compared to the term fetus, the pressor response to norepinephrine is accompanied by a baroreceptormediated bradycardia, and acetylcholine-induced systemic hypotension is accompanied by a "paradoxical" tachycardia mediated through /3-adrenergic stimulation; (7) in contrast to our finding for the fetus, the pulmonary vascular pressure of neonatal and adult sheep is unresponsive to autonomic agonists.PREVIOUS studies on fetal lambs between 60 days and term gestation (fetal weight, 300-5,00,0 g) have shown that (1) the sympathetic control of the cardiovascular functions begins earlier during fetal development than the parasympathetic control; (2) the influence of both systems on the fetal circulation increases with fetal growth until term; and (3) the fetal cardiovascular response to autonomic agonists increases during intrauterine development mainly because of maturation of the effector system. 1 ' 2The present report deals with data that compare the changes in the neurohumoral control of the heart rate, systemic arterial pressure, and pulmonary vascular pressure of the neonatal lamb (3-60 days of age) with changes in the adult nonpregnant sheep. MethodsNear-term ewes of mixed breed with well dated gestation were allowed to deliver spontaneously in our animal facilities; hence, the exact age of each lamb was known. The lambs were housed with their mothers so that normal lactation could be accomplished until they were able to eat the same alfalfa diet given to the ewes and drink on their own during the period of observation. Each lamb was allowed a 2-to 3-day period of neonatal adjustment before it was subjected to surgery. Chronic instrumentation of the lamb or the adult sheep was accomplished under a...

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Section: The Resting Systemic Arterial and Pulmonary Arterial Pressurcontrasting

confidence: 53%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: The Resting Systemic Arterial and Pulmonary Arterial Pressurmentioning

confidence: 99%

See 2 more Smart Citations

Autonomic control of cardiovascular functions during neonatal development and in adult sheep.

Woods¹,

Dandavino²,

Murayama³

et al. 1977

Circulation Research

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show abstract

“…These procedures were similar in detail to those reported previously (1,(5)(6)(7)(8)(9). Uteroplacental and fetal oxygen transfer was also studied on this group of animals but data on these studies will not be included in this report.…”

Section: Study Of Uteroplacental and Umbilical Hemodynamicsmentioning

confidence: 95%

Effects of Hyperbaric Oxygen on Uteroplacental and Fetal Circulation

Assali

Kirschbaum

Dilts

1968

Circulation Research

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The effects of hyperbaric oxygen (at 3 atmospheres absolute) on uteroplacental and fetal circulations were studied in pregnant ewes near term. The ewe was given spinal anesthesia, the fetus was marsupialized to the abdominal walls to protect the umbilical circulation, and the fetal head was covered with a saline-filled glove to prevent breathing. During hyperbaric oxygenation, maternal arterial blood Po 2 rose to 1,300 mm Hg while umbilical vein blood Poo rose to 300 mm Hg; umbilical arterial Po 2 rose to only 50 mm Hg. Maternal and fetal arterial pressures did not change significantly, but uteroplacental and umbilical flows decreased slightly. Ductus arteriosus blood flows decreased strikingly when the oxygen tension of the pulmonary blood rose; net pulmonary blood flow increased markedly because of a decrease in pulmonary vascular resistance produced by oxygen. Ascending aortic flow increased, but effective fetal cardiac output (aortic plus ductus arteriosus flows) decreased. These studies indicate that the fetal pulmonary vascular bed is sensitive to oxygen in that it undergoes vasodilatation when the oxygen tension of the blood passing through it rises; the ductus arteriosus responds to the same stimulus by constricting. Hyperbaric oxygenation seems to establish a circulatory pattern in the fetus similar to that of the early neonatal period.From the

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Neural and Endocrine Regulation of Circulation in the Fetus and Newborn

Mott

Walker

1983

Comprehensive Physiology

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Effects of autonomic blockade on pulmonary and systemic circulation before and after birth

Cited by 15 publications

References 0 publications

Autonomic control of cardiovascular functions during neonatal development and in adult sheep.

Autonomic control of cardiovascular functions during neonatal development and in adult sheep.

Effects of Hyperbaric Oxygen on Uteroplacental and Fetal Circulation

Neural and Endocrine Regulation of Circulation in the Fetus and Newborn

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