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 (PaO2 50-90 mmHg) on fetal breathing movements in the unanaesthetized fetal sheep



Effect of hyperoxia (PaO2 50-90 mmHg) on fetal breathing movements in the unanaesthetized fetal sheep



Journal of Developmental Physiology 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 silastic 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: 039924446

Download citation: RISBibTeXText

PMID: 2129170



Related references

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, 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

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

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

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

Rebound increase in fetal breathing movements after 24-h prostaglandin E2 infusion in fetal sheep. Journal of Applied Physiology 80(1): 166-175, 1996

Influence of fetal breathing movements on pulmonary hemodynamics in fetal sheep. Pediatric Research 56(6): 932-938, 2004

The central effects of morphine on fetal breathing movements in the fetal sheep. Journal of Developmental Physiology 8(4): 297-305, 1986

Prostaglandin E2 decreases fetal breathing movements, but not pulmonary blood flow, in fetal sheep. Journal of Applied Physiology 78(4): 1477-1484, 1995

Phentolamine increases the incidence of fetal breathing movements both in normoxia and in hypoxia in term fetal sheep. Journal of Physiology (Cambridge) 452: 320P, 1992

Low dose indomethacin via fetal vein or cerebral ventricle stimulates breathing movements in fetal sheep. Canadian Journal of Physiology and Pharmacology 75(2): 135-142, 1997

Effects of maternal cigarette smoking on fetal trunk movements fetal breathing movements and the fetal heart rate. British Journal of Obstetrics & Gynaecology 91(7): 657-661, 1984

Fetal breathing movements and maternal hyperoxia. British Journal of Obstetrics & Gynaecology 87(12): 1084-1086, 1980