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.
Bissonnette
J M
JM
Department of Obstetrics and Gynecology, Oregon Health Sciences University, Portland 97201.
Hohimer
A R
AR
Chao
C R
CR
Knopp
S J
SJ
Notoroberto
N F
NF
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