Ventilatory sensitivities of peripheral and central chemoreceptors of young piglets to inhalation of CO2 in air.
In 20 piglets aged 2-12 d (mean 6.8 d) and anesthetized with alpha-chloralose-urethane, we investigated the contribution of the peripheral and central chemoreceptors to the ventilatory response to inhalation of CO2 in air. For this purpose we used the dynamic end-tidal forcing technique, applying square-wave changes in end-tidal CO2 tension of 1.5-2.0 kPa at a constant end-tidal O2 tension of 15 kPa. Each response, measured on a breath-to-breath basis, was separated into a fast peripheral and a slow central component by fitting the sum of two exponentials to the measured ventilation. Each component was characterized by a CO2 sensitivity, a time constant, a time delay, and an apneic threshold. The results showed that in 2- to 12-d-old piglets the peripheral chemoreceptors are responsive to CO2 during air breathing. The contribution of the peripheral chemoreceptors in mediating the response to CO2 averaged 30 +/- 10%. Within this age range we could not demonstrate a significant correlation of the parameters characterizing the dynamic ventilatory response to CO2 with postnatal age.
Wolsink
J G
JG
Department of Physiology, University of Leiden, The Netherlands.
Berkenbosch
A
A
DeGoede
J
J
Olievier
C N
CN
D000367:Age Factors; D000388:Air; D000818:Animals; D000831:Animals, Newborn; D002245:Carbon Dioxide; D002490:Central Nervous System / Q000502:physiology; D002628:Chemoreceptor Cells / Q000502:physiology*; D005260:Female; D008297:Male; D010525:Peripheral Nerves / Q000502:physiology; D015656:Respiratory Mechanics / Q000502:physiology*; D013552:Swine
D002245:Carbon Dioxide