Theophylline stimulates fetal breathing movements during hypoxia.
The respiratory responses to theophylline during normoxia and hypoxia were determined in 13 unanesthetized fetal sheep. Theophylline (plasma levels approximately 111 mumol/L) increased the incidence of fetal breathing movements measured over 120 min from 37.7 +/- 4.8% to 61.1 +/- 5.7% (SEM) in normoxic fetuses. In isocapnic hypoxia (arterial O2 tension approximately 1.86 kPa), theophylline increased the incidence from 20.0 +/- 6.3 to 52.0 +/- 6.1%. Theophylline also resulted in an increase in the slope of inspiration during both normoxia and hypoxia. We conclude that adenosine modulates fetal respiratory drive during normoxia and hypoxia.
Department of Obstetrics and Gynecology, Oregon Health Sciences University, Portland 97201.
J M
JM
Bissonnette
A R
AR
Hohimer
C R
CR
Chao
S J
SJ
Knopp
N F
NF
Notoroberto
D000241:Adenosine / Q000037:antagonists & inhibitors / Q000502:physiology; D000818:Animals; D005260:Female; D005311:Fetal Hypoxia / Q000503:physiopathology*; D005333:Fetus / Q000187:drug effects* / Q000502:physiology; D011247:Pregnancy; D015656:Respiratory Mechanics / Q000187:drug effects* / Q000502:physiology; D012756:Sheep; D013806:Theophylline / Q000494:pharmacology*
D013806:Theophylline; D000241:Adenosine