title: Vasopressin-deficient rats show a reduced amplitude of the circadian sleep rhythm.
abstract: The hypothalamic suprachiasmatic nuclei are responsible for the generation of many circadian rhythms, including the rhythm of arginine vasopressin (AVP) in the cerebrospinal fluid (CSF). We used cortical EEG recordings taken from AVP-deficient (Brattleboro strain) rats to investigate the possible role of AVP in the generation of circadian sleep/arousal rhythms. When housed either in a light-dark cycle or in constant light, Brattleboro rats showed circadian rhythms of arousal, slow-wave sleep, and paradoxical sleep. However, the amplitudes of the slow-wave and paradoxical sleep (but not arousal) rhythms in these animals were significantly lower than in controls. The results indicate that hypothalamic synthesis of AVP is not necessary for the generation of circadian sleep rhythms, but the amplitude of the rhythms may be modulated by the circadian release of AVP into CSF.
authors.affiliation: Department of Psychology, Michigan State University, East Lansing 48824-1117.
authors.forename: M H
authors.initials: MH
authors.lastname: Brown
authors.forename: A A
authors.initials: AA
authors.lastname: Nunez
mesh_terms: D000818:Animals; D001127:Arginine Vasopressin / Q000502:physiology*; D001143:Arousal / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology*; D004569:Electroencephalography; D051381:Rats; D011910:Rats, Brattleboro / Q000502:physiology*; D011922:Rats, Mutant Strains / Q000502:physiology*; D012894:Sleep Stages / Q000502:physiology*; D012895:Sleep, REM / Q000502:physiology; D013493:Suprachiasmatic Nucleus / Q000502:physiology*
chemical_list: D001127:Arginine Vasopressin