Journal of Applied Physiology, Vol 65, Issue 4 1611-1616, Copyright © 1988 by American Physiological Society
Intracisternal DIDS enhances ventilatory response to rebreathing CO2 in rats
J. M. Adams and N. L. Johnson
Department of Biomedical Engineering, University of Virginia, Charlottesville 22901.
In 11 anesthetized rats, we tested the hypothesis that carrier-mediated
anion transport in part determines the medullary chemoreceptor response to
acute hypercapnia by infusing the transport inhibitor
4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) in mock
cerebrospinal fluid (CSF) into the cisterna magna. In five additional rats
with sham CSF infusion, we found no effect of mock CSF on the response to
rebreathing CO2. Dye infused into the cistern stained the putative
chemoreceptor areas on the ventral surface of the medulla. DIDS, at 10 to
1,000 nM, increased the respiratory response to CO2 in a dose-related
manner but had no effect on arterial pressure or heart rate. At 1,000 nM,
the hypercapnic minute ventilation response was almost doubled because of
both volume and rate of breathing. We conclude that the net effect of anion
transport is to mitigate the stimulus to the medullary chemoreceptors
during acute hypercapnia.
