Diltiazem potentiates pentobarbital-induced hypnosis via 5-HT1A and 5-HT2A/2C receptors: Role for dorsal raphe nucleus

► DRN is a possible site at which diltiazem could potentiate pentobarbital sleep. ► Diltiazem prolongs pentobarbital sleep via 5-HT1A and 5-HT2A/2C receptors. ► DRN multi-modulates sleep-wake cycle rather than being arousal nuclei only. ► The role of each DRN subdivision in sleep modulation needs to be further evaluated.