Journal of Applied Physiology, Vol 59, Issue 2 575-579, Copyright © 1985 by American Physiological Society
Denervation of peripheral chemoreceptors decreases breathing movements in fetal sheep
D. T. Murai, C. C. Lee, L. D. Wallen and J. A. Kitterman
The role of the peripheral chemoreceptors in the control of fetal breathing
movements has not been fully defined. To determine whether denervation of
the peripheral chemoreceptors affects fetal breathing movements, we studied
14 chronically catheterized fetal sheep from 120 to 138 days of gestation.
In seven fetuses the chemoreceptors were denervated by bilateral section of
the vagus and carotid sinus nerves; in seven others, sham operations were
performed. We compared several variables during two study periods: 0-5 and
6-13 days after operation. In the denervated fetuses there were significant
decreases in the incidence and amplitude of fetal breathing movements
during both study periods. There were no differences between the two groups
in incidence of low-voltage electrocortical activity, arterial pH and blood
gas tensions, fetal heart rate, mean arterial blood pressure, or duration
of survival after operation or birth weight. We conclude that denervation
of the peripheral chemoreceptors decreases fetal breathing movements. These
results indicate that the peripheral chemoreceptors are active during fetal
life and participate in the control of fetal breathing movements.
