Glucose Transport across the Rat Blood—Brain Barrier during Anesthesia

Abstract

Blood-brain barrier (BBB) glucose transport kinetics in awake rats and in pentobarbital and halothane anesthetized rats, using a 3H2O/14C-D-glucose double-indicator method corrected for cerebral blood flow at glucose concentrations from 1-80 mM, were studied. At normal glucose concentrations (5 mM), total brain glucose influx was unaltered by pentobarbital. Halothane attenuated glucose transport capacity from 1.9 to 0.4 .mu.mol/g per min and increased diffusional transport. Km was decreased 6-fold, from 12 to 2 mM. Halothane might inhibit BBB glucose transport by competing for the glucose carrier and by altering the affinity of the carrier for glucose, perhaps by altering the environment of the carrier or the carrier itself. The finging of halothane-induced increased diffusional transport of glucose across the BBB supported evidence that halothane increases the permeability of the BBB to diffusional processes.