Melatonin or a melatonin agonist corrects age-related changes in circadian response to environmental stimulus.
The effects of a melatonin agonist, S-20098, included in the diet were tested on a specific effect of aging in hamsters: the marked decline in the phase shifting effects of a 6-h pulse of darkness on a background of constant light. In contrast to young hamsters, old hamsters fed with the control diet showed little or no phase shifts in response to a dark pulse presented in the middle of their inactive or active period. Old hamsters fed with S-20098 showed phase shifts that were ~70% of the ones in young animals and significantly greater than those in old controls. The phase advancing response to a dark pulse presented during the inactive period was dose dependent and reversed after S-20098 discontinuation. Melatonin included in the diet showed comparable restorative effects on the phase shifting response to a dark pulse in old hamsters. Replacement therapy with melatonin or melatonin-related compounds could prove useful in treating, preventing, or delaying disturbances of circadian rhythmicity and/or sleep in older people.
Van Reeth
O
O
Centre d'Etudes des Rythmes Biologiques, School of Medicine, Hôpital Erasme, Université Libre de Bruxelles, 1070 Brussels, Belgium. ovanree@ulb.ac.be
Weibel
L
L
Olivares
E
E
Maccari
S
S
Mocaer
E
E
Turek
F W
FW
D000081:Acetamides / Q000097:blood / Q000494:pharmacology*; D000375:Aging / Q000502:physiology*; D000818:Animals; D002940:Circadian Rhythm / Q000187:drug effects / Q000502:physiology*; D006224:Cricetinae; D003624:Darkness; D008027:Light; D008297:Male; D008550:Melatonin / Q000819:agonists / Q000494:pharmacology*; D008647:Mesocricetus; D009043:Motor Activity / Q000187:drug effects* / Q000502:physiology; D017440:Photoperiod; D009281:Naphthalenes
D000081:Acetamides; D008550:Melatonin; C084711:agomelatine; D009281:Naphthalenes