Journal of Applied Physiology, Vol 48, Issue 2 355-361, Copyright © 1980 by American Physiological Society
Relationship of CSF pH, O2, and CO2 responses in metabolic acidosis and alkalosis in humans
G. B. Irsigler, M. J. Stafford and J. W. Severinghaus
The effect of induced metabolic acidosis (48 h of NH4Cl ingestion, BE -
10.6 +/- 1.1) and alkalosis (43 h of NaHCO3- ingestion BE 8.8 +/- 1.6) on
arterial and lumber CSF pH, Pco2, and HCO3- and ventilatory responses to
CO2 and to hypoxia was assessed in five healthy men. In acidosis lumbar CSF
pH rose 0.033 +/- 0.02 (P less than 0.05). In alkalosis CSF pH was
unchanged. Ventilatory response lines to CO2 at high O2 were displaced to
the left in acidosis (9.0 +/- 1.4 Torr) and to the right in alkalosis (4.5
+/- 1.5 Torr) with no change in slope. The ventilatory response to hypoxia
(delta V40) was increased in acidosis (P less than 0.05) and it was
decreased in four subjects in alkalosis (P, not significant). We conclude
that the altered ventilatory drives of steady-state metabolic imbalance are
mediated by peripheral chemoreceptors, and in acidosis the medullary
respiratory chemoreceptor drive is decreased.
