Effects of serotonin synthesis inhibition on sleep in hippocampectomized rats

In adult rats an anterodorsal bilateral hippocampectomy produced an increase in motor activity without modification of the amount of the different sleep stages. In hippocampectomized rats p-chlorophenylalanine produced an insomnia which can be reversed by 5-HTP. These results show that the insomnia produced by brain serotonin depletion is not a result of the hyperactivity produced by the treatments which cause such depletion.