Journal of Applied Physiology, Vol 64, Issue 2 759-766, Copyright © 1988 by American Physiological Society
Effects of meclofenamate on breathing movements in fetal sheep before delivery
L. D. Wallen, D. T. Murai, R. I. Clyman, C. H. Lee, F. E. Mauray and J. A. Kitterman
Cardiovascular Research Institute, University of California, San Francisco 94143.
There is evidence that prostaglandins (PG), specifically PGE2, participate
in the regulation of fetal breathing movements (FBM). During late
gestation, when FBM occur intermittently and primarily during low-voltage
electrocortical activity, the concentration of PGE2 in fetal plasma
([PGE2]) is high. During the days before delivery [PGE2] increases and FBM
decrease. To determine whether the increase in [PGE2] is responsible for
the concurrent decrease in FBM, we infused the prostaglandin synthase
inhibitor, meclofenamate (0.7 mg.kg-1.h-1), into eight fetal sheep
continuously for 5-13 days before delivery; five control fetuses received a
continuous infusion of the solvent for 5-11 days before delivery. Compared
with control infusion, meclofenamate caused a significant decrease in [PGE
2] until the day of delivery and a significant increase in FBM [overall and
during high-voltage electrocortical activity (HVA)] until 2 days before
delivery. Although there were significant correlations between [PGE2] and
FBM (overall and during HVA), both groups showed similar decreases in FBM
during the 2 days before delivery. We conclude that the decrease in FBM
before delivery is not dependent on the concurrent increase in [PGE2].
