ARACHIDONIC-ACID STIMULATES GLUCOSE-UPTAKE IN CEREBRAL CORTICAL ASTROCYTES

Arachidonic acid (AA) has recently been shown to influence various cel lular functions in the central nervous system. Here we report that AA increases, in a time- and concentration-dependent manner, 2-deoxy-D-[1 -H-3]glucose ([H-3]2DG) uptake in primary cultures of astrocytes prepa red from the cerebral cortex of neonatal mice. This effect is mimicked by an unsaturated fatty acid such as linolenic acid, while palmitic a nd arachidic acids, two saturated fatty acids, are inactive. Pharmacol ogical agents that increase the endogenous levels of AA by stimulating AA release (melittin) or by inhibiting its reacylation (thimerosal) a lso promote [H-3]2DG uptake by astrocytes. We also report that norepin ephrine (NE) stimulates the release of [H-3]AA from membrane phospholi pids, with an EC50 of 3 muM; this effect is accompanied, with a tempor al delay of almost-equal-to 4 min, by the stimulation of [H-3]2DG upta ke, for which the EC50 of NE is 1 muM. Since the cerebral cortex, the brain region from which astrocytes used in this study were prepared, r eceives a massive noradrenergic innervation, originating from the locu s coeruleus, the effects of NE reported here further stress the notion that certain neurotransmitters may play a role in the regulation of e nergy metabolism in the cerebral cortex and point at astrocytes as the likely targets of such metabolic effects.