OXIDIZED GLUTATHIONE PROMOTES SLEEP IN RABBITS

Glutatione is implicated in sleep regulation. There are circadian chan ges in brain glutathione levels, and nocturnal intracerebroventricular (i.c.v.) slow infusion of oxidized glutathione (GSSG) or reduced glut athione (GSH) promotes rapid-eye-movement sleep (REMS) and non-REMS (N REMS) in rats. In the present experiments, we tested the effects of GS SG on duration of sleep, NREMS intensity, and brain temperature in ano ther species, rabbits. Male New Zealand rabbits were injected with iso tonic NaCl on a baseline day and one dose of GSSG on the test day [0.1 5, 1.5, 15, and 150 mu g/rabbit, i.c.v., or 1.5 or 15 mg/kg intravenou sly (i.v.)]. Electroencephalogram (EEG), motor activity, and brain tem perature were recorded for 6 h, Injection of 15 mu g GSSG i.c.v. signi ficantly increased the time spent in NREMS in the first 3 h after the injection. Injection of 0.15, 1.5, and 150 mu g i.s.v. GSSG, as well a s systemic injections of GSSG did not affect NREMS. Intensity of NREMS as measured by EEG slow-wave activity during NREMS, and brain tempera ture were not affected by any of the treatments. These results are con sistent with the hypothesis that glutathione may be a sleep-inducing f actor in the brain. (C) 1998 Elsevier Science Inc.