Evidence for an endogenous clock in the retina of rainbow trout: II. Circadian rhythmicity of serotonin metabolism.
The purpose of the present study was to investigate patterns of circadian rhythmicity in the retina of a salmonid fish, the rainbow trout (Oncorhynchus mykiss). Our data present the first demonstration of intraretinal variations of serotonergic substances under light/dark-conditions (LD) and during continuous darkness (DD). All substances examined (serotonin, N-acetyl serotonin, 5-hydroxytryptophol, 5-hydroxyindole acetic acid) were rhythmic in LD. Serotonin, N-acetyl-serotonin, and 5-hydroxyindole acetic acid showed a preservation of specific features of rhythmicity in DD indicating the involvement of an endogenous pacemaker in the regulation of serotonin metabolism in the rainbow trout eye.
Zaunreiter
M
M
Department of General Zoology, Morphology and Ecology, University of Salzburg, Austria.
Brandstätter
R
R
Goldschmid
A
A
D000818:Animals; D002940:Circadian Rhythm; D003624:Darkness; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism; D006917:Hydroxytryptophol / Q000378:metabolism; D008027:Light; D017686:Oncorhynchus mykiss / Q000502:physiology*; D017440:Photoperiod; D012160:Retina / Q000378:metabolism*; D012701:Serotonin / Q000031:analogs & derivatives / Q000378:metabolism*
D006917:Hydroxytryptophol; D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; C006389:N-acetylserotonin