Effect of sleep and sleep deprivation on serotonergic neurotransmission in the hippocampus: a combined in vivo microdialysis/EEG study in rats - Peñalva, R G; Lancel, M; Flachskamm, C; Reul, J M; Holsboer, F; Linthorst, A C (Eur J Neurosci, 2003)