title: Melatonin has differential effects on age-induced stoichiometric changes in daily chronomics of serotonin metabolism in SCN of male Wistar rats.
abstract: Suprachiasmatic nucleus (SCN) controls various physiological, endocrine and behavioral functions by regulating conversion of serotonin (5-HT) to melatonin (MEL). Aging leads to alterations in the neural and temporal organization of the SCN leading to circadian dysfunction. Age-induced stoichiometric alterations in daily chronomics of various components of 5-HT metabolism were studied by constructing interactomes between parameters. The levels of tryptophan (TRP), 5-hydroxytryptophan (5-HTP), 5-hydroxytryptamine (5-HT), N-acetylserotonin (NAS), N-acetyl 5-methoxytryptamine (MEL), 5-hydroxyindoleacetic acid (5-HIAA), 5-methoxyindole acetic acid (5-MIAA), 5-hydroxytryptophol (5-HTOH), 5-methoxytryptophol (5-MTOH) and N-acetyltryptamine (NAT) were measured at (Zeitgeber time 0, 6, 12 and 18) in male rat SCN of 3, 12 and 24 months age groups. Age-induced decrease was observed in mean levels of NAS, MEL, 5-HIAA, 5-MIAA, 5-MTOH, and NAT and increase was observed in TRP, 5-HTP, 5-HT and 5-HTOH in rat SCN. Daily pulses decreased with aging significantly for TRP, 5-HT, NAS, MEL, 5-HIAA, 5-MIAA and NAT. We report here, the age-induced change in interactions between various 5-HT metabolism components by middle age (12 m) changing further by 24 m. The daily rhythms persisted with aging for NAS, MEL and 5-HTOH. Though, rhythms were abolished for TRP, 5-HTP, 5-HIAA, 5-MIAA, 5-MTOH and NAT differentially at 12 and 24 m. The MEL administration showed restoration in 5-HT ratio with 5-HTP, MEL and 5-HTOH in 24 m and NAS and 5-HIAA in 12 m SCN. Thus, MEL administration effects alterations of age-induced stoichiometry in levels and chronomics of serotonin metabolic network interactomes.
authors.affiliation: Neurobiology and Molecular Chronobiology Laboratory, Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad, 500046, India.
authors.forename: M Y
authors.initials: MY
authors.lastname: Reddy
authors.forename: Anita
authors.initials: A
authors.lastname: Jagota
mesh_terms: D006916:5-Hydroxytryptophan / Q000378:metabolism; D000375:Aging / Q000378:metabolism*; D000818:Animals; D002909:Chronobiology Phenomena / Q000187:drug effects* / Q000502:physiology; D002940:Circadian Rhythm / Q000187:drug effects / Q000502:physiology; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism; D008297:Male; D008550:Melatonin / Q000494:pharmacology*; D023421:Models, Animal; D051381:Rats; D017208:Rats, Wistar; D012701:Serotonin / Q000031:analogs & derivatives / Q000378:metabolism*; D013493:Suprachiasmatic Nucleus / Q000378:metabolism*
chemical_list: D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D006916:5-Hydroxytryptophan; D008550:Melatonin; C006389:N-acetylserotonin