Journal of Applied Physiology, Vol 47, Issue 4 818-826, Copyright © 1979 by American Physiological Society
Effect of cerebral extracellular fluid acidity on total and regional cerebral blood flow
S. L. Britton, L. O. Lutherer and D. G. Davies
Total and regional cerebral blood flow (CBF), and cerebrospinal fluid
(CSF), and arterial blood acid-base status were measured in 26
chloralose-urethan-anesthetized dogs before and after 30 and 60 min of
ventriculocisternal perfusion with artificial CSF equilibrated with 7% CO2
and containing either low (8.7 or 9.1 meq/l), normal (19.6 meq/l), or high
(34.7 meq/l) bicarbonate ion concentration ([HCO3-]). An inverse linear
relationship was observed between the CSF pH and total CBF. Regional blood
flow changes were greater in structures that were closest to the
ventricular system. In addition, regional blood flow changes were greater
in all tissues studied after 60 min of perfusion than after 30. Perfusion
with the control [HCO3-] caused no significant changes in either acid-base
status or CBF. We believe that the regional cerebral blood flow changes are
the result of changes in the H+ concentration gradient across the cerebral
extracellular fluid (ECF) space due to the diffusional exchange of HCO3-
between CSF and ECF. It is concluded that cerebral ECF acidity is important
in the local regulation of cerebral blood flow.
