Cardiovascular Effects of Electrical Stimulation of the Forebrain in the Fetal Lamb

Williams, Robert L.; Hof, Robert P.; Heymann, Michaël; Rudolph, Abraham M.

doi:10.1203/00006450-197601000-00008

Cited by 12 publications

(4 citation statements)

References 10 publications

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“…19 Conversely, electrical stimulation of the hypothalamus in a fetal sheep model increases heart rate and blood pressure, a response which is blocked by an alpha-adrenoceptor antagonist. 20 Stimulation of the medial prefrontal cortex (in animal model), which has connections with the amygdala, hippocampus, thalamus, hypothalamus, parabrachial nucleus, and the NTS, induces bradycardia and hypotension and modulates gastric secretion. 9 Activation of the insula, an important visceral sensorimotor area, induces hypertension, tachycardia, piloerection, pupillary dilation, salivation, and alters gastrointestinal function.…”

Section: Anatomy and Function Of The Developing Central Ansmentioning

confidence: 99%

The Critical Role of the Central Autonomic Nervous System in Fetal-Neonatal Transition

Mulkey

Plessis

2018

Seminars in Pediatric Neurology

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Objective: The objective of this article is to understand the complex role of the central autonomic nervous system in normal and complicated fetal-neonatal transition and how autonomic nervous system dysfunction can lead to brain injury. Findings: The central autonomic nervous system supports coordinated fetal transitional cardiovascular, respiratory, and endocrine responses to provide safe transition of the fetus at delivery. Fetal and maternal medical and environmental exposures can disrupt normal maturation of the autonomic nervous system in utero, cause dysfunction, and complicate fetal-neonatal transition. Brain injury may both be caused by autonomic nervous system failure and contribute directly to autonomic nervous system dysfunction in the fetus and newborn. Conclusion: The central autonomic nervous system has multiple roles in supporting transition of the fetus. Future studies should aim to improve real-time monitoring of fetal autonomic nervous system function and in supporting typical autonomic nervous system development even under complicated conditions.

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Section: Anatomy and Function Of The Developing Central Ansmentioning

confidence: 99%

The Critical Role of the Central Autonomic Nervous System in Fetal-Neonatal Transition

Mulkey

Plessis

2018

Seminars in Pediatric Neurology

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“…Chemoreceptors in the carotid sinus may respond to low arterial oxygen tension by initiating a vagal reflex. Recently, electrical stimulation of the fetal hypothalamus has been shown to increase (12) vagal tone. The low arterial oxygen, therefore, may stimulate autonomic centers in the fetal central nervous system to increase parasympa thetic output.…”

Section: Baroreflexmentioning

confidence: 99%

Cardiovascular Responses to Autonomic Blockade in Hypoxemic Fetal Lambs

Lewis

Donovan

Platzker³

1980

Neonatology

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The cardiovascular responses of 11 fetal lambs in utero to hypoxemia were evaluated before and after autonomic blockade. Hypoxemia was produced by lowering the maternally inspired oxygen or by progressive constriction of the umbilical cord by a cuff occluder. The animals were studied serially from 112 days’ gestation to term. Fetal carotid arterial pO₂ fell from 24 to 12 torr and was accompanied by a 35% decline in heart rate and 32% rise in blood pressure. Parasympathetic blockade with atropine produced a 114% increase in heart rate in the hypoxemic fetuses compared to 26% in the normoxemic controls. Pretreatment with atropine prevented the hypoxemia-induced bradycardia without altering the hypertensive response. α-Adrenergic blockade resulted in a 22% decrease in blood pressure in the hypoxemic group, three times greater than the controls. Pre-hypoxemia α-blockade prevented the hypertension without affecting the fall in fetal heart rate. It is concluded that fetal bradycardia in response to hypoxemia is due to a direct increase in parasympathetic activity rather than secondary to a hypertension-induced baroreflex. The α-mediated increase in systemic vascular resistance and blood pressure may be a compensatory mechanism to maintain placental blood flow despite the decline in combined ventricular output.

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“…Recently, Williams et al (2) have reported that electrical stimulation of the fetal hypo thalamus resulted in three cardiovascular re sponse patterns: a tachycardia response abol ished by propranolol; a bradycardia response blocked by atropine; and a pressor-tachycardia response abolished by phentolamine and pro pranolol, respectively. They concluded that a suprabulbar framework exists in the fetal lamb above 0.6 gestation which may have a role in the central nervous regulation of circulation.…”

Section: Discussionmentioning

confidence: 99%

“…Recently, Williams et al (2) demonstrated autonomically mediated changes in heart rate and blood pressure follow ing electrical stimulation of the fetal hypothala mus and suggested that a suprabulbar neural ' The authors gratefully acknowledge the technical assistance of Reuben Wade and the preparation of the manuscript by Mrs. '/Allah Brye. framework exists in the fetal lamb which can influence the cardiovascular system.…”

mentioning

confidence: 99%

Cardiovascular Responses to Autonomic Blockade in Brain-Injured Fetal Lambs

Lewis¹,

Nestor²,

Dahms³

et al. 1978

Neonatology

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The cardiovascular responses to autonomic blockade were investigated in 15 late-gestation fetal lambs in utero. 4 animals had normal brains and 11 had hydranencephalic-like cerebral injury secondary to bilateral carotid artery obstruction (BCO). Following atropine administration, heart rate increased only 0.7 ± 0.7% in the BCO lambs compared to 25.7 ± 5.2% in the controls. α-Blockade with phentolamine resulted in a small decrease in systolic (2.2 ± 0.8%) and diastolic (1.8 ± 1.4%) blood pressure, and β-blockade with propranolol produced a small decrease in heart rate (2.5 ± 0.8%) as compared to control fetuses. Post mortem examination revealed extensive destruction of the cerebrum but normal hypothalamus and brain stem. These data suggest that supramedullary modification of autonomic cardiovascular control involves the cerebrum.

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Cardiovascular Effects of Electrical Stimulation of the Forebrain in the Fetal Lamb

Cited by 12 publications

References 10 publications

The Critical Role of the Central Autonomic Nervous System in Fetal-Neonatal Transition

The Critical Role of the Central Autonomic Nervous System in Fetal-Neonatal Transition

Cardiovascular Responses to Autonomic Blockade in Hypoxemic Fetal Lambs

Cardiovascular Responses to Autonomic Blockade in Brain-Injured Fetal Lambs

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