AJP - Gastrointestinal and Liver Physiology, Vol 244, Issue 2 145-G150, Copyright © 1983 by American Physiological Society
Acute respiratory alkalosis and acidosis and rabbit intestinal ion transport in vivo
A. N. Charney, M. Arnold and N. Johnstone
The effects of acute respiratory alkalosis and acidosis on electrolyte
transport in the rabbit ileum, colon, and gallbladder were studied. During
in situ perfusion, anesthetized animals were ventilated with 0, 3, or 8%
CO2 gas, creating states of alkalosis (pH 7.49 +/- 0.01, PCO2 = 27.0 +/-
0.9 mmHg, HCO3 = 21.7 mM), normocapnia (pH 7.38 +/- 0.02, PCO2 = 41.3 +/-
1.1 mmHg, HCO3 = 25.9 +/- 0.4 mM), and acidosis (pH 7.21 +/- 0.01, PCO2 =
66.3 +/- 1.3 mmHg, HCO3 = 28.1 +/- 0.8 mM). In the ileum alkalosis
decreased the net absorption of water (-36%), sodium (-44%), and chloride
(-27%), whereas acidosis had the opposite effect on water (+69%), sodium
(+98%), and chloride (+32%) absorption and reduced bicarbonate secretion.
Small changes in net potassium absorption occurred in the direction of
water movement. There was no effect on the ileal transmural potential
difference (PD). The colon and gallbladder did not respond to the acid-base
disorders with changes in electrolyte transport or PD. These results
suggest that systemic pH and/or PCO2 affect an electroneutral sodium
chloride absorptive process in the rabbit ileum. The simple presence of
this absorptive process in the gallbladder was not a sufficient basis for
this organ to respond to alterations in systemic pH.
