Relationship of CSF pH, O2, and CO2 responses in metabolic acidosis and alkalosis in humans.
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.
D000138:Acidosis / Q000134:cerebrospinal fluid*; D000328:Adult; D000471:Alkalosis / Q000134:cerebrospinal fluid*; D002245:Carbon Dioxide / Q000134:cerebrospinal fluid*; D002344:Carotid Body / Q000502:physiology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008526:Medulla Oblongata / Q000502:physiology; D008875:Middle Aged; D010100:Oxygen / Q000134:cerebrospinal fluid*; D012119:Respiration
D002245:Carbon Dioxide; D010100:Oxygen