title: How does the circadian clock send timing information to the brain?
abstract: This paper discusses circadian output in terms of the signaling mechanisms used by circadian pacemaker neurons. In mammals, the suprachiasmatic nucleus houses a clock controlling several rhythmic events. This nucleus contains one or more pacemaker circuits, and exhibits diversity in transmitter content and in axonal projections. In Drosophila, a comparable circadian clock is located among period -expressing neurons, a sub-set of which (called LN-vs) express the neuropeptide PDF. Genetic experiments indicate LN-vs are the primary pacemakers neurons controlling daily locomotion and that PDF is the principal circadian transmitter. Further definition of pacemaker properties in several model systems will provide a useful basis with which to describe circadian output mechanisms.
authors.affiliation: Department of Anatomy & Neurobiology, Box 8108, Washington University School of Medicine, 660 South Euclid Avenue, Saint Louis, MO 63110, USA. taghertp@pcg.wustl.edu
authors.forename: P H
authors.initials: PH
authors.lastname: Taghert
mesh_terms: D000818:Animals; D001683:Biological Clocks / Q000235:genetics / Q000502:physiology; D001921:Brain / Q000502:physiology*; D002940:Circadian Rhythm; D004330:Drosophila / Q000235:genetics / Q000502:physiology; D029721:Drosophila Proteins; D015870:Gene Expression; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism; D008322:Mammals; D009474:Neurons / Q000502:physiology; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D013493:Suprachiasmatic Nucleus / Q000502:physiology*; D014667:Vasopressins / Q000235:genetics / Q000502:physiology
chemical_list: D029721:Drosophila Proteins; D019476:Insect Proteins; D009479:Neuropeptides; C113883:pdf protein, Drosophila; D014667:Vasopressins