[Effect of DL-tryptophan on photic evoked potentials and basic activity of the EEG]

The effects of DL-tryptophan on photic evoked potentials (photic after discharges--PhNE, photic recruitment--PhR, photic evoked primary potential--PhEP) and basic activity of EEG were investigated in freely moving rats with chronically implanted electrodes in various areas of cortex. DL-tryptophan increased the number of PhNE potentials and particularly the number of NE potentials per answered lightflashes (NE/bLB). The effects depend on dosage of DL-tryptophan. The double impulse stimulation confirmed these results. The power spectral show an increased synchronization of the background EEG activity. The results are discussed in connection with local serotoninergic effects and influences on vigilance by 5-hydroxytryptamine.