Rats were kept on a low-K+ diet for 25 or 70 days. Local cerebral blood flow (LCBF) and local cerebral glucose utilization (LCGU) were measured in 31 different structures of the brain by means of the [14C]iodoantipyrine and [14C]2-deoxy-D-glucose method. After 25 and 70 days of K+ depletion LCBF was decreased significantly in 27 and 30 structures, respectively, the average decrease being 19 and 25%. In contrast, average LCGU was not changed. Cisternal cerebrospinal fluid (CSF) K+ concentration decreased significantly from 2.65 +/- 0.02 mM in controls to 2.55 +/- 0.02 mM and 2.47 +/- 0.02 mM in the two treated groups (P less than 0.01). CSF [HCO3-], pH, and PCO2 were increased in K+-depleted animals. These data show that K+ depletion induces an increase in CSF pH and a decrease in CSF K+ concentration, both of which cause a reduction in cerebral blood flow. The increased CSF PCO2 is secondary to the reduction of blood flow, since brain metabolism and arterial PCO2 remained constant.
Effects of Buflomedil on survival rate, local cerebral blood flow and glucose utilization after cerebral ischemia in spontaneously hypertensive rats.