Cerebral blood flow, glucose use, and CSF ionic regulation in potassium-depleted rats.
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.
D000136:Acid-Base Equilibrium; D000818:Animals; D001921:Brain / Q000378:metabolism*; D002245:Carbon Dioxide / Q000032:analysis; D002560:Cerebrovascular Circulation; D003847:Deoxyglucose / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007477:Ions / Q000134:cerebrospinal fluid*; D007773:Lactates / Q000134:cerebrospinal fluid; D019344:Lactic Acid; D008297:Male; D011191:Potassium Deficiency / Q000378:metabolism* / Q000503:physiopathology; D051381:Rats; D011919:Rats, Inbred Strains
D007477:Ions; D007773:Lactates; D002245:Carbon Dioxide; D019344:Lactic Acid; D003847:Deoxyglucose; D005947:Glucose