Lithium/nutrition interaction in the brain: A single lithium administration impairs spreading depression in malnourished, but not in well-nourished rats

Abstract

Lithium salts exert electrophysiological and behavioral effects in animals and humans and have been used clinically in the treatment of bipolar disorders. Little is known about the lithium/nutrition interaction in the developing brain. This work aimed to determine, in adult rats, whether treatment with a single dose of lithium chloride (LiCl) would influence the propagation of the brain excitability-related phenomenon known as cortical spreading depression (CSD). Male well-nourished (W; fed a lab chow diet with 22% protein; n=22) and previously protein-malnourished rats (M; fed a low-quality 8% protein diet; proteins mostly from vegetable source; n=20) were treated at 75-80 days of age with a single intraperitoneal injection of either 50 mg/kg LiCl (n=9 W and 10 M rats) or saline (n=13 W and 10 M rats). When the pups were 90-110 days, CSD was elicited at the frontal cortex and recorded during 4 hours at two cortical parietal points. In malnourished, but not in well-nourished rats, lithium treatment lowered CSD velocities (P < 0.05), in comparison with saline-injected animals. In a third group (n=23), in which the low-protein diet was quantitatively corrected to 22%, the lithium effect disappeared (n=12), compared to saline (n=11). Our results demonstrate a facilitating effect of malnutrition on the CSD-impairing action of a single lithium administration, suggesting a lithium/nutrition interaction.