title: Circadian activity rhythms in rats with midbrain raphe lesions.
abstract: The dorsal and median mesencephalic raphe nuclei provide a robust projection to the hypothalamic suprachiasmatic nucleus, the site of a putative neuronal circadian pacemaker. Although it has been suggested that the raphe may play a role in the circadian timing system, this role has not yet been specified. In the present report, we examined the circadian activity patterns of rats with large mid-brain lesions aimed at the median and dorsal raphe nuclei under conditions of light-dark entrainment, and while free-running in constant light and constant darkness. The results indicate that midbrain raphe lesions may interfere with the expression of free-running circadian activity rhythms.
mesh_terms: D000818:Animals; D001931:Brain Mapping; D002940:Circadian Rhythm; D005260:Female; D008636:Mesencephalon / Q000502:physiology*; D009043:Motor Activity / Q000502:physiology*; D011903:Raphe Nuclei / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000502:physiology; D013493:Suprachiasmatic Nucleus / Q000502:physiology
chemical_list: D012701:Serotonin