| Abstract: | Young adult Louis rats were implanted for chronic sleep recording to test the effect of diethyldithiocarbamate (DDC) on sleep. Recordings of EEG and EMG were done continuously for 12 h during the 12 consecutive days. There were 2 days of baseline recording, 3 days of recording with a single daily injection of placebo, 3 days of recording with a single daily injection of DDC (500 mg/kg i.p.), and 3 days of DDC withdrawal recording with placebo injection. Placebo injections did not change the proportion of time spent in different behavioural states. With daily injection of DDC there was an increase in wakefulness, no change in slow-wave sleep and elimination or drastic reduction in paradoxical sleep (PS). There was no PS rebound during the DDC withdrawal days. These results suggest that the reduction of PS produced by DDC and the absence of PS rebound may be due to a lowering in norepinephrine in the brain. In other experiments rats were injected with DDC (500 mg/kg i.p.) daily for 3 days and whole brains were analysed chemically. Norepinephrine was significantly decreased, while 5-hydroxytryptamine, 5-hydroxyindolacetic acid, dopamine and homovanilic acid were unchanged. Seizure activity appeared during relaxed wakefulness in all rats treated with DDC. Taken together it seems that lowering of brain NE is responsible for the appearance of seizure activity and also, for PS reduction. PS reduction might, per se, produce seizure activity. |
