Journal of Applied Physiology, Vol 55, Issue 1 177-182, Copyright © 1983 by American Physiological Society
Regulation of CSF composition--blocking chloride-bicarbonate exchange
H. Frankel and H. Kazemi
The possibility that the increase in cerebrospinal fluid (CSF) [HCO-3]
observed during respiratory acidosis could be the result of a decrease in
CSF [Cl-] was studied by blocking a putative Cl--HCO-3 exchange transport
system. Anesthetized dogs (pentobarbital 30 mg, iv) were given either
4,4'-diisothiocyano-2,2'-disulfonate stilbene (DIDS, 0.02 mumol/kg) or
pyridoxal 5-phosphate (P-5-P, 4 mumol/kg) in the lateral cerebral
ventricles and maintained either normocapnic (RA) or hypercapnic (5% CO2).
CSF and arterial Pco2, pH, [Na+], [K+], [Ca2+], [Cl-], and [lactate] were
determined. [HCO-3] was calculated. Samples were drawn before and 4 h after
the drug was administered. In control dogs on RA no significant change was
observed in any measured parameter after 4 h. Dogs receiving either DIDS or
P-5-P and on RA had decreased CSF [Na+] of 2-4 meq/l and CSF [Cl-] of 6
meq/l. CSF [HCO-3] in DIDS dogs decreased approximately 5 meq/l. There was
no significant change in CSF [HCO-3] in P dogs. After 4 h of 5% CO2,
control dogs had decreased CSF [Cl-] of 3 meq/l and CSF [HCO-3] increased
approximately 4 meq/l. Dogs receiving DIDS or P-5-P and breathing 5% CO2
for 4 h had decreased CSF [Cl-] of 6-9 meq/l and [HCO-3] increased of 7-9
meq/l. CSF [Na+] did not change during respiratory acidosis in any group.
It was concluded the Cl- transport in CSF can be interfered with by use of
blocking agents which inhibit Cl--HCO-3 exchange channels.
