EurekaMag.com logo
+ Site Statistics
References:
53,869,633
Abstracts:
29,686,251
+ Search Articles
+ Subscribe to Site Feeds
EurekaMag Most Shared ContentMost Shared
EurekaMag PDF Full Text ContentPDF Full Text
+ PDF Full Text
Request PDF Full TextRequest PDF Full Text
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter
Follow on LinkedInFollow on LinkedIn

+ Translate

Effect of hyperoxia arterial partial pressure of oxygen 50 90 mmhg on fetal breathing movements in the unanesthetized fetal sheep



Effect of hyperoxia arterial partial pressure of oxygen 50 90 mmhg on fetal breathing movements in the unanesthetized fetal sheep



Journal of Developmental Physiology (Eynsham) 14(4): 235-241



Hypoxia inhibits fetal breathing movements but after birth it stimulates breathing. These differences have long been thought to involve central nervous inhibitory mechanisms. Such mechanisms might exert a tonic inhibition of fetal breathing movements at normal fetal PaO2 and the rise in PaO2 at birth might lift this inhibitory effect. To test this hypothesis 7 fetal sheep were chronically instrumented at 125-130 days for recording electrocortical activity (ECoG), and the electromyograph (EMG) activity of the diaphragm and neck muscles. Catheters were placed in a fetal carotid and a brachial artery and in the fetal trachea. For an extracorporeal membrane oxygenation system a 12 F gauge sylastic catheter was placed in the right atrium for draining fetal blood and a 9.6 F gauge catheter was placed in a carotid artery to return oxygenated blood. Three days after operation the fetuses were connected to the extracorporeal membrane oxygenation system and fetal PaO2 was raised to 65.2 .+-. 4.4 mmHg (SEM) for 6 to 19 h without changing pH or PaCO2. Neither the incidence of high voltage ECoG (48.5 .+-. SEM 2.0% vs 52.8 .+-. 3.3%) nor of fetal breathing movements (37.3 .+-. 2.6% vs 23.8% .+-. 5.9%) changed during the periods of hyperoxia. Since fetal breathing movements did not become continuous, we conclude that the lower PaO2 in the fetus compared to the neonate does not exert a tonic inhibitory influence on fetal breathing movements.

(PDF emailed within 1 workday: $29.90)

Accession: 007250005

Download citation: RISBibTeXText



Related references

Effect of hyperoxia (PaO2 50-90 mmHg) on fetal breathing movements in the unanaesthetized fetal sheep. Journal of Developmental Physiology 14(4): 235-241, 1990

Effects of fetal behavioral states on renal sympathetic nerve activity and arterial pressure of unanesthetized fetal sheep. American Journal of Physiology. Regulatory, Integrative and Comparative Physiology 285(4): R908-R916, 2003

Interdependence of arterial partial pressure of oxygen and oxygen consumption in the fetal sheep. Journal of Developmental Physiology (Eynsham) 13(4): 205-214, 1990

The effect of fetal breathing movements on pulmonary blood flow in fetal sheep. Pediatric Research 35(4 Pt 1): 484-489, 1994

Effect of morphine on fetal electrocortical activity and breathing movements in fetal sheep. Developmental Pharmacology and Therapeutics 8(2): 115-128, 1985

Effect of alterations of oxygen pressure and carbon di oxide pressure on fetal breathing movements in rhesus monkeys. Gynecologic Investigation 6(1/2): 74, 1975

Phenyl iso propyl adenosine causes alteration in fetal electro corticogram patterns and cessation of fetal breathing movements in the fetal sheep. Pediatric Research 18(4 PART 2): 160A, 1984

Effects of fetal seizure activities on fetal heart rate, blood pressure and breathing movements in fetal lambs. American Journal of Obstetrics & Gynecology 174(1 PART 2): 380, 1996

Effect of maternal ethanol infusion on fetal breathing movements and brainstem extracellular fluid adenosine and prostaglandin E2 in near-term fetal sheep. Alcoholism Clinical & Experimental Research 25(5 Supplement A): 34A, 2001

Effect of prolonged catecholamine infusion on heart rate, blood pressure and breathing movements in fetal sheep. American Journal of Obstetrics & Gynecology 168(1 PART 2): 327, 1993

The effects of raising intracranial pressure on breathing movements, eye movements and electrocortical activity in fetal sheep. Journal of Developmental Physiology 8(2): 105-116, 1986

Comparison of continuous trans cutaneous oxygen partial pressure measurement with intermittent arterial oxygen partial pressure determinations in fetal lambs. Obstetrics & Gynecology 57(2): 248-252, 1981

Effect of acutely-induced lactic acidemia on fetal breathing movements, heart rate, blood pressure, ACTH and cortisol in sheep. Journal of Developmental Physiology 16(1): 45-50, 1991

Ethanol and ovine fetal breathing movements, fetal breathing movements, fetal prostaglandin E-2 and myometrial activity. Alcoholism Clinical & Experimental Research 17(2): 459, 1993

The incidence of fetal breathing movements fetal trunk movements and total fetal activity in normal growth retarded and diabetic pregnancies and factors influencing fetal activity. British Journal of Radiology 53(630): 624, 1980